Perioperative mortality after hemiarthroplasty related to fixation method

Background and purpose

The appropriate fixation method for hemiarthroplasty of the hip as it relates to implant survivorship and patient mortality is a matter of ongoing debate. We examined the influence of fixation method on revision rate and mortality.

Methods

We analyzed approximately 25,000 hemiarthroplasty cases from the AOA National Joint Replacement Registry. Deaths at 1 day, 1 week, 1 month, and 1 year were compared for all patients and among subgroups based on implant type.

Results

Patients treated with cemented monoblock hemiarthroplasty had a 1.7-times higher day-1 mortality compared to uncemented monoblock components (p < 0.001). This finding was reversed by 1 week, 1 month, and 1 year after surgery (p < 0.001). Modular hemiarthroplasties did not reveal a difference in mortality between fixation methods at any time point.

Interpretation

This study shows lower (or similar) overall mortality with cemented hemiarthroplasty of the hip.The frequency of hip fractures is increasing with our ageing population, with an annual incidence of between 1.4 and 5 per 103 per year (Lonnroos et al. 2006, Icks et al. 2008, Varez-Nebreda et al. 2008). Health model projections have estimated that 6.3 million hip fractures will occur annually worldwide within the next 40 years (Cooper et al. 1992), imposing a significant economic health burden. There is a large reported perioperative mortality rate in this population, ranging from 2.4% to 8.2% at 1 month (Parvizi et al. 2001, Radcliff et al. 2008) and over 25% at 1 year (Elliott et al. 2003, Jiang et al. 2005). Furthermore, it was recently reported that the current mortality rate is higher now than 25 years ago (Vestergaard et al. 2007a). Today, it is generally accepted that displaced intracapsular fractures are best treated with arthroplasty rather than internal fixation (Keating et al. 2006, Leighton et al. 2007). In the at-risk population, however, multiple comorbidities are common and the best form of component fixation is in question.Bone cement implantation syndrome is a well-described complication of cemented hip arthroplasty. It is characterized by a systemic drop in systolic blood pressure, hypoxemia, pulmonary hypertension, cardiac dysrhythmias, and occasionally cardiac arrest and death (Rinecker 1980, Orsini et al. 1987, Parvizi et al. 1999). The prevailing theory to explain the pathophysiology of this phenomenon is embolism of fat, marrow contents, bone, and to some degree methylmethacrylate to the lung (Rinecker 1980, Elmaraghy et al. 1998, Parvizi et al. 1999, Koessler et al. 2001). An increased degree of pulmonary insult with fat microemboli has been demonstrated (mostly in randomized controlled trials) during insertion of a cemented femoral stem rather than an uncemented implant (Orsini et al. 1987, Ries et al. 1993, Christie et al. 1994, Pitto et al. 1999), presumably due to increased intramedullary femoral canal pressures in the cemented group (Kallos et al. 1974, Orsini et al. 1987). These pressures can be reduced by the use of distal venting holes in the femur during stem insertion (Engesæter et al. 1984). It has been shown previously by single-institutional review that patients undergoing cemented hip arthroplasty have a higher intraoperative mortality rate relative to uncemented arthroplasty, presumably due to a reduced incidence of fat embolism in the latter group (Parvizi et al. 1999). The increased mortality risk was also present at 30 days in the treatment of acute fractures with cemented arthroplasty, also from a single-institutional review (Parvizi et al. 2004). Although cement-related mortality is rare (Dearborn and Harris 1998, Parvizi et al. 1999, 2001, 2004, Weinrauch et al. 2006), it is a devastating complication—often reported through observational studies or literature reviews. Proponents of uncemented hip arthroplasty often cite this concern to support their reluctance to use cemented hip arthroplasty in both elective procedures and fracture management. However, many different types of studies have been unable to identify any increased mortality risk with the use of cement (Lausten and Vedel 1982 (observational), Emery et al. 1991 (RCT), Lo et al. 1994 (observational), Khan et al. 2002a,b (literature review), Parker and Gurusamy 2004 (literature review)) and others have shown a decrease in mortality at 30 days when cement is used (Foster et al. 2005).Cemented hip hemiarthroplasty appears to offer improved rate of return to baseline function, reduced postoperative pain, and superior long-term survivorship relative to uncemented arthroplasty (Khan et al. 2002a, b, Parker and Gurusamy 2004). We reasoned that failure to return to baseline function after hemiarthroplasty may be another risk factor for perioperative mortality (Hannan et al. 2001, Braithwaite et al. 2003). Lower revision rates for cemented prostheses and increased mortality at revision surgery contribute further to reducing the overall mortality risk. We evaluated the relationship between the method of fixation of hip arthroplasty and perioperative mortality using a large national joint replacement registry.     

Role of preoperative pain,muscle function,and activity level in discharge readiness after fast-track hip and knee arthroplasty

Methods Before surgery, hip pain (THA) or knee pain (TKA), lower-extremity muscle power, functional performance, and physical activity were assessed in a sample of 150 patients and used as independent variables to predict the outcome (dependent variable)—readiness for hospital discharge —for each type of surgery. Discharge readiness was assessed twice daily by blinded assessors.Results Median discharge readiness and actual length of stay until discharge were both 2 days. Univariate linear regression followed by multiple linear regression revealed that age was the only independent predictor of discharge readiness in THA and TKA, but the standardized coefficients were small (≤ 0.03).Interpretation These results support the idea that fast-track THA and TKA with a length of stay of about 2–4 days can be achieved for most patients independently of preoperative functional characteristics.Over the last decade, length of stay (LOS) with discharge to home after primary THA and TKA has declined from about 5–10 days to about 2–4 days in selected series and larger nationwide series (Malviya et al. 2011, Raphael et al. 2011, Husted et al. 2012, Kehlet 2013, Hartog et al. 2013, Jørgensen and Kehlet 2013). However, there is a continuing debate about whether selected patients only or all patients should be scheduled for “fast-track” THA and TKA in relation to psychosocial factors and preoperative pain and functional status (Schneider et al. 2009, Hollowell et al. 2010, Macdonald et al. 2010, Antrobus and Bryson 2011, Jørgensen and Kehlet 2013), or whether organizational or pathophysiological factors in relation to the surgical trauma may determine the length of stay (Husted et al. 2011, Husted 2012).We studied the role of THA and TKA patients’ preoperative pain and functional characteristics in discharge from 2 orthopedic departments with well-established fast-track recovery regimens (Husted et al. 2010).     

Congenital pseudarthrosis of the tibia treated with a combination of Ilizarov��s technique and intramedullary rodding: 15 cases followed for mean 4.5 years

Background and purpose

Ilizarov’s technique and intramedullary rodding have often been used individually in congenital pseudarthrosis of the tibia. In this series, we attempted to combine the advantages of both methods while minimizing the complications.

Methods

We reviewed 15 cases of congenital pseudoarthrosis of the tibia (CPT) who were treated with a combination of Ilizarov’s apparatus and antegrade intramedullary nailing between 2003 and 2008. The mean age at surgery was 7.5 (3–12) years and the mean limb length discrepancy was 2.5 (1.5–5) cm. At a mean follow-up time of 4.5 (1.6–7.2) years after the index surgery, the patients were evaluated clinically and radiographically for ankle function (AOFAS score) and for malalignment, signs of union, limb length discrepancy, and complications.

Results

14 patients achieved union, in 6 patients primary union and in 8 patients after secondary procedures. The AOFAS score improved from a preoperative mean of 40 (20–57) to 64 (47–75). The main complication was refracture in 1 patient, and non-union in 1 patient.

Interpretation

The combination of the Ilizarov technique and conventional antegrade intramedullary nailing was successful in achieving union with few complications, though this should be shown in long-term studies lasting until skeletal maturity.Congenital pseudarthrosis of the tibia (CPT), also called congenital tibial dysplasia, is difficult to treat with a substantial risk of non-union, refractures, leg length discrepancy (LLD), and malalignment of the tibia and the ankle (Plawecki et al. 1990, Paley et al. 1992). Treatment procedures can be broadly classified into 3 groups: (1) Intramedullary rodding (usually trans-ankle) with bone grafting (Johnston 2002, Dobbs et al. 2004), (2) microvascular fibular transfer (Ohnishi et al. 2005), and (3) the Ilizarov technique with its various modifications (Paley et al. 1992, Boero et al. 1997, Johnston and Birch 2008). However, no single treatment has been shown to be uniformly effective.Intramedullary rodding, usually retrograde through the calcaneum to the tibia, has been used relatively widely with success in achieving union and protection against refracture (Johnston 2002, Shah et al. 2011). However, concerns still exist about ankle stiffness and arthritic changes in the ankle following the nailing (Dobbs et al. 2005). On the other hand, various series using the Ilizarov technique have shown high union rates with good ankle function (Paley et al. 1992, Boero et al. 1997). However, there is a risk of refracture with this technique. We therefore wanted to make use of the advantages of both techniques. We have found only 1 report on this combined method (Mathieu et al. 2008) involving 10 cases.We report the clinico-radiographical outcomes of 15 patients with CPT who were treated with a combination of the Ilizarov technique and intramedullary rodding.     

Survival and prognostic factors in chondrosarcoma: results in 115 patients with long-term follow-up

Background and purpose

There have been few long-term studies on the outcome of chondrosarcoma and the findings regarding prognostic factors are controversial. We examined a homogeneous group of patients with primary central chondrosarcoma of bone who were treated according to a uniform surgical protocol at our institution, in order to determine the factors that influence survival and identify potential improvements to our therapeutic algorithm.

Patients and methods

We performed a retrospective analysis of 115 patients with primary central chondrosarcoma of bone who presented with localized disease and who had a minimum follow-up of 5 years after diagnosis. 68 tumors were localized in the extremities and 47 in the axial skeleton or pelvis. 59 patients had a high-grade (II and III) and 56 a low-grade (I) tumor. 94 patients underwent surgical resection with adequate (wide or radical) margins, while 21 patients had inadequate (marginal or intralesional) margins.

Results

Tumor grade and localization were found to be statistically significant independent predictors of disease-related deaths in multivariate analysis. The quality of surgical margins did not influence survival. The AJCC staging system was able to predict prognosis in patients with chondrosarcoma of the extremities, but not in those with tumors of the axial skeleton and pelvis. Long-term survival after secondary metastatic disease was only observed when metastases were resected with wide margins. Patients with metastases who received further treatment with conventional chemotherapy, radiotherapy, and/or further surgery had significantly better survival compared to those who received best supportive care.

Interpretation

The outcome in patients with primary central chondrosarcoma of bone who present with localized disease is mostly affected by tumor-related parameters.Chondrosarcoma is the second most common primary malignant solid tumor of bone, and accounts for approximately 25% of all bone sarcomas (Bertoni et al. 2002). It is largely considered to be resistant to conventional chemotherapy and radiotherapy (Healey and Lane 1986, Campanacci 1999, Gelderbloom et al. 2008). As such, surgical resection has been the cornerstone of treatment for over 50 years (Dahlin and Henderson 1956, Healey and Lane 1986, Gelderbloom et al. 2008). However, in recent years several novel therapeutic approaches have been evaluated in experimental studies (Morioka et al. 2003, Gouin et al. 2006, Klenke et al. 2007, Delaney et al. 2009, Schrage et al. 2009, 2010).There is no consensus on prognostic factors to determine which patients have a higher risk of treatment failure and disease-related deaths, although several papers have addressed this issue (Evans et al. 1977, Pritchard et al. 1980, Gitelis et al. 1981, Björnsson et al. 1998, Lee et al. 1999, Rizzo et al. 2001, Fiorenza et al. 2002). One reason may be that most studies have included patients treated over several decades, with no account for the different surgical criteria, indications, and methods applied over the years. Furthermore, most studies have included patients with short follow-up, despite the fact that a high rate of late recurrence and metastasis has been reported for chondrosarcoma patients compared to those with other primary bone sarcomas (Evans et al. 1977, Pritchard et al. 1980), as well as patients with rare histopathological subtypes that have a distinct biologic behavior (Lee et al. 1999, Bertoni et al. 2002, Gelderbloom et al. 2008) such as dedifferentiated chondrosarcoma, mesenchymal chondrosarcoma, and clear cell chondrosarcoma, thus reducing the validity of the results.The purpose of this long-term retrospective study was to examine a group of patients with primary central chondrosarcoma of bone who presented with localized disease and were treated with a uniform surgical protocol at our institution, in order to determine the factors that influence overall and event-free survival. We further aimed at identifying potential improvements to our therapeutic algorithm.     

Wrist function recovers more rapidly after volar locked plating than after external fixation but the outcomes are similar after 1 year

Background and purpose

Promising results have been reported after volar locked plating of unstable dorsally displaced distal radius fractures. We investigated whether volar locked plating results in better patient-perceived, objective functional and radiographic outcomes compared to the less invasive external fixation.

Patients and methods

63 patients under 70 years of age, with an unstable extra-articular or non-comminuted intra-articular dorsally displaced distal radius fracture, were randomized to volar locked plating (n = 33) or bridging external fixation. Patient-perceived outcome was assessed with the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire and the Patient-Rated Wrist Evaluation (PRWE) questionnaire.

Results

At 3 and 6 months, the volar plate group had better DASH and PRWE scores but at 12 months the scores were similar. Objective function, measured as grip strength and range of movement, was superior in the volar plate group but the differences diminished and were small at 12 months. Axial length and volar tilt were retained slightly better in the volar plate group.

Interpretation

Volar plate fixation is more advantageous than external fixation, in the early rehabilitation period.The risk of a poor outcome after a fracture of the distal radius increases with malunion (Grewal and MacDermid 2007) and in highly unstable fractures, operative fixation is required to maintain a satisfactory anatomical position. Closed reduction and bridging external fixation rely on ligamentotaxis to reduce and keep the fracture in alignment. It has been used for unstable distal radius fractures for several decades. External fixation requires 5–6 weeks of immobilization, and some fracture redisplacement often occurs after the fixation device has been removed (Dicpinigaitis et al. 2004, Handoll et al. 2007). In later years, there has been a strong trend towards open reduction and internal fixation with volar locked plating in the management of unstable, dorsally displaced, fractures of the distal radius. Volar locked plating facilitates an anatomical reduction of the fracture, it stabilizes the fracture during the entire healing process, and it allows early wrist mobilization. Good results in terms of patient-rated outcome scores, objective function, and radiographic outcome have been reported both in younger and older patients (Orbay and Fernandez 2002, 2004, Kamano et al. 2005, Chung et al. 2006, Oshiege et al. 2007, Jupiter et al. 2009). Several studies have compared dorsal plating (Grewal et al. 2005, Kateros et al. 2010), fragment-specific systems (Abramo et al. 2009), or a mixture of dorsal and volar plating techniques (Kreder et al. 2005, Leung et al. 2008) with external fixation, but there is no substantial evidence to support the use of internal fixation instead of external fixation (Margaliot et al. 2005). Few studies have compared volar locked plating with external fixation, and there is still insufficient evidence regarding which gives the best outcome (Wright et al. 2005, Egol et al. 2008, Rizzo et al. 2008, Wei et al. 2009).We have carried out a randomized comparison of open reduction with volar locked plating and closed reduction with bridging external fixation for unstable dorsally displaced extra-articular and non-comminuted intra-articular fractures of the distal radius. Our hypothesis was that volar locked plating would result in better patient-perceived, objective functional, and radiographic outcome after 12 months than external fixation.     

Longer hospital stay,more complications,and increased mortality but substantially improved function after knee replacement in older patients: A study of 3,144 primary unilateral total knee replacements

Background and purpose

Total knee replacement (TKR) is being increasingly performed in elderly patients, yet there is little information on specific requirements and complication rates encountered by this group. We assessed whether elderly patients undergoing TKR had different length of stay, requirements, complication rates, and functional outcomes compared to younger counterparts.

Patients and methods

We analyzed prospectively gathered data on 3,144 consecutive primary TKRs (in 2,092 patients aged less than 75 years, 694 patients aged between 75 and 80 years, and 358 patients aged over 80 years at the time of surgery).

Results

Incidence of blood transfusion, urinary catheterization, postoperative confusion, cardiac arrhythmia, and 1-year mortality increased with age, even after adjusting for confounding factors, whereas the incidences of chest infection and mortality at 1 month were highest in those aged 75–80. Rates of thromboembolism, prosthetic infection, and revision were similar in the 3 age groups. All groups showed similar substantial improvements in American Knee Society (AKS) knee scores, which were maintained at 5 years. Older patients had smaller improvements in AKS function score, which deteriorated between 3 and 5 years postoperatively, in contrast to the younger group.

Interpretation

Elderly people stand to gain considerably from TKR, particularly in terms of pain relief, and they should not be denied surgery based solely on age. However, they should be warned that they can expect a longer length of stay, a higher requirement for blood transfusion and/or urinary catheterization, and more medical complications postoperatively. Mortality was also higher in the older age groups. The risks have been quantified to assist in perioperative counselling, informed consent, and healthcare planning.Healthcare systems and medical professionals will need to cater for increasing numbers of total knee replacements (TKRs) in elderly people in the coming years (Carr et al. 2012), but little is known about inpatient requirements and the postoperative complications suffered by this particular patient group. Some studies have shown good joint-specific pain relief and functional benefits from TKR in the elderly (Anderson et al. 1996, Birdsall et al. 1999), although it has been suggested that elderly patients may attain lower global function than their younger counterparts (Clement et al. 2011, Kennedy et al. 2013). However, studies attempting to describe complications in the elderly undergoing TKR have been small (Zicat et al. 1993, Hosick et al. 1994, Joshi et al. 2003), have lacked comparator groups (Hosick et al. 1994, Joshi et al. 2003), or have failed to quantify the time scales within which complications have occurred (Clement et al. 2011, Kennedy et al. 2013). Other studies and registries have been based on discharge summary databases without specific patient follow-up (Kreder et al. 2005, Mahomed et al. 2005, Scottish Arthroplasty Project, 2012). They therefore relied on third-party coding of discharge summaries and reported only on mortality during the index admission (Kreder et al. 2005) or selected complications requiring hospital re-admission within 30 or 90 days (Kreder et al. 2005, Mahomed et al. 2005, Scottish Arthroplasty Project, 2012).The aim of this study was to determine whether elderly patients undergoing TKR had different postoperative length of stay, inpatient requirements (i.e. blood transfusion and urinary catheterization), complication rates, and mortality rates to those of their younger counterparts. Functional outcomes were assessed as a secondary outcome measure, to determine whether elderly patients gained benefit comparable to that of their younger counterparts, independently of recorded admission requirements and complications.     

Why still in hospital after fast-track hip and knee arthroplasty?

Background and purpose

Length of stay (LOS) following total hip and knee arthroplasty (THA and TKA) has been reduced to about 3 days in fast-track setups with functional discharge criteria. Earlier studies have identified patient characteristics predicting LOS, but little is known about specific reasons for being hospitalized following fast-track THA and TKA.

Patients and methods

To determine clinical and logistical factors that keep patients in hospital for the first postoperative 24–72 hours, we performed a cohort study of consecutive, unselected patients undergoing unilateral primary THA (n = 98) or TKA (n = 109). Median length of stay was 2 days. Patients were operated with spinal anesthesia and received multimodal analgesia with paracetamol, a COX-2 inhibitor, and gabapentin—with opioid only on request. Fulfillment of functional discharge criteria was assessed twice daily and specified reasons for not allowing discharge were registered.

Results

Pain, dizziness, and general weakness were the main clinical reasons for being hospitalized at 24 and 48 hours postoperatively while nausea, vomiting, confusion, and sedation delayed discharge to a minimal extent. Waiting for blood transfusion (when needed), for start of physiotherapy, and for postoperative radiographic examination delayed discharge in one fifth of the patients.

Interpretation

Future efforts to enhance recovery and reduce length of stay after THA and TKA should focus on analgesia, prevention of orthostatism, and rapid recovery of muscle function.Total hip and total knee arthroplasty (THA and TKA) are frequent operations with an average length of stay (LOS) of about 6–12 days in the United Kingdom, Germany, and Denmark (Husted et al. 2006, Bundesauswertung 2009, NHS 2010).During the last decade, however, there has been increased interest in optimal multimodal perioperative care to enhance recovery (the fast-track methodology). Improvement of analgesia; reduction of surgical stress responses and organ dysfunctions including nausea, vomiting, and ileus; early mobilization; and oral nutrition have been of particular interest (Kehlet 2008, Kehlet and Wilmore 2008). These principles have also been applied to THA and TKA, resulting in improvements in pain treatment with multimodal opioid-sparing regimens including a local anesthetic infiltration technique (LIA) or peripheral nerve blocks to facilitate early mobilization (Ilfeld et al. 2006a, b, 2010a, Andersen et al. 2008, Kerr and Kohan 2008), and allowing functional rehabilitation to be initiated a few hours postoperatively (Holm et al. 2010)—ultimately leading to a reduction in LOS (Husted et al. 2008, Barbieri et al. 2009, Husted et al. 2010a, b). Using these evidence-based regimens combined with an improved logistical setup, LOS is reduced to about 2–4 days (Kerr and Kohan 2008, Husted et al. 2010 a,b,c, Lunn et al. 2011).Having well-defined functional discharge criteria is imperative in order to ensure a safe discharge—and it is mandatory if meaningful comparison of LOS is done following alterations in the track (Husted et al. 2008). In the same fast-track setting, an earlier study focused on patient characteristics predicting LOS (Husted et al. 2008). However, little is known about the specific reasons for why patients are hospitalized during the first 1–3 days after THA or TKA; i.e. why can patients not be discharged?We therefore analyzed clinical and organizational factors responsible for being hospitalized in a well-defined prospective setup in a fast-track unit. This unit had previously documented LOS of about 2–3 days (Andersen et al. 2008, Holm et al. 2010, Husted et al. 2010b, c, Lunn et al. 2011).     

Metal-backed versus all-polyethylene tibial components in primary total knee arthroplasty

Background and purpose

The choice of either all-polyethylene (AP) tibial components or metal-backed (MB) tibial components in total knee arthroplasty (TKA) remains controversial. We therefore performed a meta-analysis and systematic review of randomized controlled trials that have evaluated MB and AP tibial components in primary TKA.

Methods

The search strategy included a computerized literature search (Medline, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials) and a manual search of major orthopedic journals. A meta-analysis and systematic review of randomized or quasi-randomized trials that compared the performance of tibial components in primary TKA was performed using a fixed or random effects model. We assessed the methodological quality of studies using Detsky quality scale.

Results

9 randomized controlled trials (RCTs) published between 2000 and 2009 met the inclusion quality standards for the systematic review. The mean standardized Detsky score was 14 (SD 3). We found that the frequency of radiolucent lines in the MB group was significantly higher than that in the AP group. There were no statistically significant differences between the MB and AP tibial components regarding component positioning, knee score, knee range of motion, quality of life, and postoperative complications.

Interpretation

Based on evidence obtained from this study, the AP tibial component was comparable with or better than the MB tibial component in TKA. However, high-quality RCTs are required to validate the results.The design of the tibial component is an important factor for implant failure in total knee arthroplasty (TKA) (Pagnano et al. 1999, Forster 2003, Gioe et al. 2007b, Willie et al. 2008, Garcia et al. 2009, KAT Trial Group 2009). The metal-backed (MB) design of tibial component has become predominant in TKA because it is thought to perform better than the all-polyethylene (AP) design (Muller et al. 2006, Gioe et al. 2006, 2007a,b). In theory, the MB tibial component reduces bending strains in the stem, reduces compressive stresses in the cement and cancellous bone beneath the baseplate (especially during asymmetric loading), and distributes load more evenly across the interface (Bartel et al. 1982, 1985, Taylor et al. 1998). However, critics of the MB tibial component claim that there are expensive implant costs, reduced polyethylene thickness with the same amount of bone resection, backside wear, and increased tensile stresses at the interface during eccentric loading (Bartel et al. 1982, 1985, Pomeroy et al. 2000, Rodriguez et al. 2001, Li et al. 2002, Muller et al. 2006, Blumenfeld and Scott 2010, Gioe and Maheshwari 2010).In the past decade, several randomized controlled trials (RCTs) have been performed to assess the effectiveness of the MB tibial component (Adalberth et al. 2000, 2001, Gioe and Bowman 2000, Norgren et al. 2004, Hyldahl et al. 2005a, b, Muller et al. 2006, Gioe et al. 2007, Bettinson et al. 2009, KAT Trial Group 2009). However, data have not been formally and systematically analyzed using quantitative methods in order to determine whether the MB tibial component is indeed optimal for patients in TKA. In this study, we wanted (1) to determine the scientific quality of published RCTs comparing the AP and MB tibial components in TKA using Detsky score (Detsky et al. 1992) and (2) to conduct a meta-analysis and systematic review of all published RCTs that have compared the effects of AP and MB tibial components on the radiographic and clinical outcomes of TKA.     

Metal release and metal allergy after total hip replacement with resurfacing versus conventional hybrid prosthesis: 5-year follow-up of 52 patients

Background

Metal-on-metal (MOM) total hip arthroplasties were reintroduced because of the problems with osteolysis and aseptic loosening related to polyethylene wear of early metal-on-polyethylene (MOP) arthroplasties. The volumetric wear rate has been greatly reduced with MOM arthroplasties; however, because of nano-size wear particles, the absolute number has been greatly increased. Thus, a source of metal ion exposure with the potential to sensitize patients is present. We hypothesized that higher amounts of wear particles result in increased release of metal ions and ultimately lead to an increased incidence of metal allergy.

Methods

52 hips in 52 patients (median age 60 (51–64) years, 30 women) were randomized to either a MOM hip resurfacing system (ReCap) or a standard MOP total hip arthoplasty (Mallory Head/Exeter). Spot urine samples were collected preoperatively, postoperatively, after 3 months, and after 1, 2, and 5 years and tested with inductively coupled plasma-sector field mass spectrometry. After 5 years, hypersensitivity to metals was evaluated by patch testing and lymphocyte transformation assay. In addition, the patients answered a questionnaire about hypersensitivity.

Results

A statistically significant 10- to 20-fold increase in urinary levels of cobalt and chromium was observed throughout the entire follow-up in the MOM group. The prevalence of metal allergy was similar between groups.

Interpretation

While we observed significantly increased levels of metal ions in the urine during the entire follow-up period, no difference in prevalence of metal allergy was observed in the MOM group. However, the effect of long-term metal exposure remains uncertain.In the 1960s and 1970s, the articulations of hip implants were mainly metal-on-metal (MOM). The implants released cobalt, chromium, and nickel, which could be found in high levels in the blood, hair, and urine (Coleman et al. 1973, Benson et al. 1975, Elves et al. 1975, Gawkrodger 2003). Furthermore, the patients became sensitized to the metals released and an association with early loosening was observed (Coleman et al. 1973, Benson et al. 1975, Elves et al. 1975, Gawkrodger 2003, Jacobs et al. 2009). Gradually, MOM implants were abandoned and the work by Sir John Charley with the metal-on-polyethylene (MOP) bearing advanced hip replacement substantially. However, the MOM articulation was reintroduced in the 1990s, as it became clear that polyethylene debris caused osteolysis, which was a significant clinical issue—especially in young and active patients (Marshall et al. 2008). The MOM Hip Resurfacing System has been proposed to have advantages such as enhanced longevity (Chan et al. 1999, Sieber et al. 1999, Firkins et al. 2001), enhanced implant fixation (Grigoris et al. 2006), lower dislocation rate (Scifert et al. 1998), better reproduction of hip mechanics, and more native femoral shaft bone stock left for revision surgery (Shimmin et al. 2008).MOM articulations have greatly reduced the volumetric wear rate of hip prostheses; however, because of nano-sized metal wear particles, the absolute number of wear particles has greatly increased (Doorn et al. 1998, Chan et al. 1999, Sieber et al. 1999, Firkins et al. 2001, Rieker and Kottig. 2002). Also, Hallab et al. (2004) suggested that the prevalence of metal allergy could be higher in patients with implant failure. In both cases, a source of metal ion exposure with the potential to sensitize patients is present, but the long-term biological effect of the metal wear debris remains unknown.Metal hypersensitivity is a well-established phenomenon and is common, affecting about 10–15% of the general population (Thyssen and Menne 2010). Metal allergy can develop after prolonged or repeated cutaneous exposure to metal, usually from consumer products. Affected individuals typically suffer from allergic contact dermatitis and react with cutaneous erythema, papules, and vesicles after skin contact. This reaction is categorized as a type-4 T-cell-mediated hypersensitivity reaction. Also, metal hypersensitivity may develop following internal exposure to metal-releasing implants. Theoretically, metal hypersensitivity could lead to a powerful reaction to prosthesis implantation (Pandit et al. 2008).We hypothesized that an increased number of wear particles from MOM hip resurfacing arthroplasty (HRA) would lead to increased blood levels and urinary excretion of metal ions, and ultimately to an increased prevalence of metal allergy.     

Hospital volume affects outcome after total knee arthroplasty: A nationwide registry analysis of 80 hospitals and 59,696 replacements

ResultsThe greater the volume of the hospital, the shorter was the average LOS and LUIC. Smaller hospital volume was not unambiguously associated with increased revision, re-admission, or MUA rates. The smaller the annual hospital volume, the more often patients were discharged home.InterpretationLOS and LUIC ought to be shortened in lower-volume hospitals. There is potential for a reduction in length of stay in extended institutional care facilities.Total knee replacement (TKR) is one of the most common orthopedic procedures, and it is expected to increase markedly in volume (Kurtz et al. 2007). Due to the potentially severe complications and the high economic impact of the procedure, efforts to minimize the risks and optimize perioperative efficiency are important.It has been suggested that increased hospital volume and reduction in length of stay (LOS) at the operating hospital after TKR are related, but there is no consensus (Yasunaga et al. 2009, Marlow et al. 2010, Paterson et al. 2010, Bozic et al. 2010, Styron et al. 2011). In addition, results on the association of hospital volume with re-admission rates (Soohoo et al. 2006b, Judge et al. 2006, Bozic et al. 2010, Cram et al. 2011) and revision risk have been inconclusive (Shervin et al. 2007, Manley et al. 2009, Bozic et al. 2010, Paterson et al. 2010). No-one has tried to study the association between length of uninterrupted institutional care (LUIC), incidence of manipulation under anesthesia (MUA) after TKR, and hospital volume.By combining 5 national-level registries, we examined possible associations between hospital volume and LOS, LUIC, discharge disposition, number of re-admissions within 14 and 42 days, MUA, and revisions after TKR for all knee arthroplasties performed in Finland between 1998 and 2010.     

The influence of age, delay of repair, and tendon involvement in acute rotator cuff tears: structural and clinical outcomes after repair of 42 shoulders

Background and purpose

Few authors have considered the outcome after acute traumatic rotator cuff tears in previously asymptomatic patients. We investigated whether delay of surgery, age at repair, and the number of cuff tendons involved affect the structural and clinical outcome.

Patients and methods

42 patients with pseudoparalysis after trauma and no previous history of shoulder symptoms were included. A full-thickness tear in at least 1 of the rotator cuff tendons was diagnosed in all patients. Mean time to surgery was 38 (6–91) days. Follow-up at a mean of 39 (12–108) months after surgery included ultrasound, plain radiographs, Constant-Murley score, DASH score, and western Ontario rotator cuff (WORC) score.

Results

At follow-up, 4 patients had a full-thickness tear and 9 had a partial-thickness tear in the repaired shoulder. No correlation between the structural or clinical outcome and the time to repair within 3 months was found. The patients with a tendon defect at follow-up had a statistically significantly lower Constant-Murley score and WORC index in the injured shoulder and were significantly older than those with intact tendons. The outcomes were similar irrespective of the number of tendons repaired.

Interpretation

A delay of 3 months to repair had no effect on outcome. The patients with cuff defects at follow-up were older and they had a worse clinical outcome. Multi-tendon injury did not generate worse outcomes than single-tendon tears at follow-up.“Codman''s trauma theory” postulated that trauma may rupture healthy rotator cuff tendons but that the rupture most often occurs in cases where aged tendons are weakened by overuse or degeneration (Fukuda 2000, Sorensen et al. 2007). Still, cuff ruptures with sudden pseudoparalysis occurring after trauma are usually considered acute, and immediate repair has been recommended (Bassett and Cofield 1983, Lahteenmaki and Lawrence 2007, Petersen and Murphy 2011). Almost all previous studies concerning rotator cuff repair have included patients with both acute and chronic degenerative tears. In the clinical setting, it is difficult to distinguish an acute tear from a degenerative one with acute symptoms after trauma (Bassett and Cofield 1983, Lahteenmaki and Lawrence 2007, Sorensen et al. 2007, Petersen and Murphy 2011). Since there have been few studies, with few participants and including only acute traumatic tears, little is known about the result after repair in this group of patients (Bassett and Cofield 1983, Lahteenmaki and Lawrence 2007, Petersen and Murphy 2011).The Swedish national guidelines state that acute full-thickness tears with pseudoparalysis after trauma in previously asymptomatic patients should be repaired within 3 weeks (Swedish National Musculoskeletal Competence Centre 2006). There is little support for this guideline in the literature. To our knowledge, only a few previous studies have examined the effect of time to surgery after acute traumatic tear. Bassett and Cofield (1983) found that early repair within 3 weeks resulted in better shoulder function but Petersen and Murphy (2011) stated that the clinical outcome is not affected by a surgical delay of 4 months. As stated by Codman and others (Fukuda 2000, Sorensen et al. 2007, Perry et al. 2009, Duquin et al. 2010), most traumatic cuff tears occur in aged tendons. However, the influence of age on the results after acute cuff repair has not been studied in detail.The number of cuff tendons injured has been reported to affect the structural and clinical outcomes in chronic tears, but as far as we know the same correlations have not been reported in patients with acute tears (Jost et al. 2006, Zingg et al. 2007, Nho et al. 2009a, Oh et al. 2009, 2010). Structural defects following repair of chronic tears have been reported to range between 13% and 94% (Fuchs et al. 2006, Jost et al. 2006, Zingg et al. 2007, Oh et al. 2009). To our knowledge, there have been no reports regarding maintenance of tendon integrity following repair of acute tears.We investigated whether the structural and clinical outcomes after surgical repair of an acute rotator cuff tear in a previously asymptomatic patient are influenced by delay in repair, age at repair, and the extent of the initial cuff injury.     

PCR-hybridization after sonication improves diagnosis of implant-related infection

Purpose

We wanted to improve the diagnosis of implant-related infection using molecular biological techniques after sonication.

Methods

We studied 258 retrieved implant components (185 prosthetic implants and 73 osteosynthesis implants) from 126 patients. 47 patients had a clinical diagnosis of infection (108 components) and 79 patients did not (150 components). The fluids from sonication of retrieved implants were tested in culture and were also analyzed using a modified commercial PCR kit for detection of Gram-positive and Gram-negative bacteria (GenoType BC; Hain Lifescience) after extraction of the DNA.

Results

38 of 47 patients with a clinical diagnosis of infection were also diagnosed as being infected using culture and/or PCR (35 by culture alone). Also, 24 patients of the 79 cases with no clinical diagnosis of infection were identified microbiologically as being infected (4 by culture, 16 by PCR, and 4 by both culture and PCR). Comparing culture and PCR, positive culture results were obtained in 28 of the 79 patients and positive PCR results were obtained in 35. There were 21 discordant results in patients who were originally clinically diagnosed as being infected and 28 discordant results in patients who had no clinical diagnosis of infection.

Interpretation

For prosthetic joint infections and relative to culture, molecular detection can increase (by one tenth) the number of patients diagnosed as having an infection. Positive results from patients who have no clinical diagnosis of infection must be interpreted carefully.Management of orthopedic implant-related infections starts with a proper etiological diagnosis, which is required for specific antibiotic treatment. Different approaches are used to obtain such a diagnosis (Trampuz et al. 2006, Del Pozo and Patel 2009) and these must take into account the importance of the development of bacterial biofilms in the pathogenesis and management of implant-related infections (Trampuz et al. 2003, 2006, Costerton 2005).The use of low-intensity ultrasound that releases biofilms is an alternative to classical culture methods from implants, and several protocols have been developed for this purpose (Trampuz et al. 2007, Dora et al. 2008, Esteban et al. 2008, Piper et al. 2009, Achermann et al. 2010). In these reports, the use of sonication of retrieved implants was reported to have similar sensitivity to or higher sensitivity than conventional techniques. Nevertheless, there are still patients with a clinical diagnosis of infection and negative cultures (Berbari et al. 2007). Previous use of antibiotics has been implicated as one of the main causes of this problem (Trampuz et al. 2007), but other causes are also possible. To solve the problem, molecular biological techniques have been proposed in order to obtain faster and more accurate results than conventional culture (Tunney et al. 1999, Sauer et al. 2005, Dempsey et al. 2007, Fihman et al. 2007, Moojen et al. 2007, Gallo et al. 2008, Kobayashi et al. 2008, Vandercam et al. 2008, De Man et al. 2009, Piper et al. 2009, Achermann et al. 2010, Riggio et al. 2010, Marin et al. 2012). Most of these reports were based on protocols that were developed in-house, which are difficult to integrate into clinical microbiology routines, even though they may give good results. Recently, however, commercial kits have been designed to work under common routine laboratory conditions. Here, we describe a study on the diagnosis of infection in a broad range of orthopedic implant-related infections, comparing conventional culture with detection of microbial DNA using a commercial kit—in both cases after sonication of retrieved implants.     

CRP and leukocyte-count after lumbar spine surgery: fusion vs. nucleotomy

Background

Despite the fact that C-reactive protein (CRP) levels and white blood cell (WBC) count are routine blood chemistry parameters for the early assessment of wound infection after surgical procedures, little is known about the natural history of their serum values after major and minimally invasive spinal procedures.

Methods

Pre- and postoperative CRP serum levels and WBC count in 347 patients were retrospectively assessed after complication-free, single-level open posterior lumbar interlaminar fusion (PLIF) (n = 150) for disc degeneration and spinal stenosis and endoscopically assisted lumbar discectomy (n = 197) for herniated lumbar disc. Confounding variables such as overweight, ASA classification, arterial hypertension, diabetes mellitus, and perioperative antibiotics were recorded to evaluate their influence on the kinetics of CRP values and WBC count postoperatively.

Results

In both procedures, CRP peaked 2–3 days after surgery. The maximum CRP level was significantly higher after fusion: mean 127 (SD 57) (p < 0.001). A rapid fall in CRP within 4–6 days was observed for both groups, with almost normal values being reached after 14 days. Only BMI > 25 and long duration of surgery were associated with higher peak CRP values. WBC count did not show a typical and therefore interpretable profile.

Conclusion

CRP is a predictable and responsive serum parameter in postoperative monitoring of inflammatory responses in patients undergoing spine surgery, whereas WBC kinetics is unspecific. We suggest that CRP could be measured on the day before surgery, on day 2 or 3 after surgery, and also between days 4 and 6, to aid in early detection of infectious complications.In spinal surgery, the rate of postoperative deep wound infection depends on the type of surgery and on patients'' premorbidity, and ranges from 0.7% for simple nucleotomy to over 3.5% for fusion with instrumentation, and can reach 20% in patients with metastatic disease (Wimmer et al. 1998, Weinstein et al. 2000). Early detection of postoperative infection, especially in spine surgery, can be difficult. Numerous plasma values have been used in monitoring of infection-related responses after spine surgery. These plasma determinations range from simple and inexpensive tests such as erythrocyte sedimentation rate (ESR) (Thelander and Larsson 1992, Meyer et al. 1995) to the complex determination of soluble biomarkers of inflammatory response such as quantification of cytokines (Huang et al. 2005). The value of ESR as an early marker of infection has been disputed (Larsson et al 1990, Meyer et al. 1995, Khan et al. 2006) and the latter methods are complicated and difficult to interpret, and are also very expensive.The acute-phase-related C-reactive protein (CRP) is a feasible parameter for detection and monitoring of postoperative wound infections and systemic inflammatory response syndromes (Foglar and Lindsey 1998, Neumaier et al. 2006, Takahashi et al. 2006). Serial CRP measurements are useful not only as a diagnostic tool for infection, but also for monitoring the effect of treatment and for the early detection of relapse (Larsson et al 1990, Codine et al. 2005, Mok et al. 2008). As with other orthopedic surgical procedures, surgery of the spine induces a temporary rise in CRP (Garnavos et al. 2005, Neumaier et al. 2006, Mok et al. 2008). One prerequisite for the use of CRP as a diagnostic aid after spine surgery in the early detection of postoperative infection is an understanding of the natural CRP response induced by the procedure. To establish this baseline, we examined CRP levels and white blood cell (WBC) count after 2 types of surgical procedures of the lumbar spine. In addition, we assessed the degree to which postoperative CRP kinetics is influenced by patient comorbidity and by perioperative administration of prophylactic antibiotics.     

Locking plate osteosynthesis in displaced 4-part fractures of the proximal humerus

Background and purpose

There is considerable uncertainty about the optimal treatment of displaced 4-part fractures of the proximal humerus. Within the last decade, locking plate technology has been considered a breakthrough in the treatment of these complex injuries.

Methods

We systematically identified and reviewed clinical studies on the benefits and harms after osteosynthesis with locking plates in displaced 4-part fractures.

Results

We included 14 studies with 374 four-part fractures. There were 10 case series, 3 retrospective observational comparative studies, 1 prospective observational comparative study, and no randomized trials. Small studies with a high risk of bias precluded reliable estimates of functional outcome. High rates of complications (16–64%) and reoperations (11–27%) were reported.

Interpretation

The empirical foundation for the value of locking plates in displaced 4-part fractures of the proximal humerus is weak. We emphasize the need for well-conducted randomized trials and observational studies.There is considerable uncertainty about the optimal treatment of displaced 4-part fractures of the proximal humerus (Misra et al. 2001, Handoll et al. 2003, Bhandari et al. 2004, Lanting et al. 2008). Only 2 small inconclusive randomized trials have been published (Stableforth 1984, Hoellen et al. 1997). A large number of interventions are used routinely, ranging from a non-operative approach to open reduction and internal fixation (ORIF), and primary hemiarthroplasty (HA).In the last decade, locking plate technology has been developed and has been heralded as a breakthrough in the treatment of fractures in osteoporotic bone (Gautier and Sommer 2003, Sommer et al. 2003, Haidukewych 2004, Miranda 2007). Locking plate technique is based on the elimination of friction between the plate and cortex, and relies on stability between the subchondral bone and screws. Multiple multidirectional convergent and divergent locking screws enhance the angular stability of the osteosynthesis, possibly resulting in better postoperative function with reduced pain. Reported complications include screw cut-out, varus fracture collapse, tuberosity re-displacement, humeral head necrosis, plate impingement, and plate or screw breakage (Hall et al. 2006, Tolat et al. 2006, van Rooyen et al. 2006, Agudelo et al. 2007, Gardner et al. 2007, Khunda et al. 2007, Ring 2007, Smith et al. 2007, Voigt et al. 2007, Egol et al. 2008, Kirchhoff et al. 2008, Owsley and Gorczyca 2008, Brunner et al. 2009, Micic et al. 2009, Sudkamp et al. 2009). The balance between the benefit and harms of the intervention seems delicate.Several authors of narrative reviews and clinical series have strongly recommended fixation of displaced 4-part fractures of the humerus with locking plates (Bjorkenheim et al. 2004, Hente et al. 2004, Hessler et al. 2006, Koukakis et al. 2006, Kilic et al. 2008, Korkmaz et al. 2008, Shahid et al. 2008, Papadopoulos et al. 2009, Ricchetti et al. 2009) and producers of implants unsurprisingly strongly advocate them (aap Implantate 2010, Stryker 2010, Synthes 2010, Zimmer 2010). Despite the increasing use of locking plates (Illert et al. 2008, Ricchetti et al. 2009), we have been unable to identify systematic reviews on the benefits and harms of this new technology in displaced 4-part fractures. Thus, we systematically identified and reviewed clinical studies on the benefits and harms after osteosynthesis with locking plates in displaced 4-part fractures of the proximal humerus.     

Hydroxyapatite coating does not improve uncemented stem survival after total hip arthroplasty!: An analysis of 116,069 THAs in the Nordic Arthroplasty Register Association (NARA) database

ResultsUnadjusted 10-year survival with the endpoint revision of any component for any reason was 92.1% (CI: 91.8–92.4). Unadjusted 10-year survival with the endpoint stem revision due to aseptic loosening varied between the stem brands investigated and ranged from 96.7% (CI: 94.4–99.0) to 99.9% (CI: 99.6–100). Of the stem brands with the best survival, stems with and without HA coating were found. The presence of HA coating was not associated with statistically significant effects on the adjusted risk of stem revision due to aseptic loosening, with an HR of 0.8 (CI: 0.5–1.3; p = 0.4). The adjusted risk of revision due to infection was similar in the groups of THAs using HA-coated and non-HA-coated stems, with an HR of 0.9 (CI: 0.8–1.1; p = 0.6) for the presence of HA coating. The commonly used Bimetric stem (n = 25,329) was available both with and without HA coating, and the adjusted risk of stem revision due to aseptic loosening was similar for the 2 variants, with an HR of 0.9 (CI: 0.5–1.4; p = 0.5) for the HA-coated Bimetric stem.InterpretationUncemented HA-coated stems had similar results to those of uncemented stems with porous coating or rough sand-blasted stems. The use of HA coating on stems available both with and without this surface treatment had no clinically relevant effect on their outcome, and we thus question whether HA coating adds any value to well-functioning stem designs.Hydroxyapatite (HA) is thought to improve early implant ingrowth and long-term stability in bone (Overgaard et al. 1997), and many stems intended for uncemented total hip arthroplasty (THA) are thus manufactured with HA coating. Several uncemented stems are only available with HA coating. Some HA-coated stems have excellent long-term outcomes in terms of the risk of revision, both for any reason and due to aseptic loosening (Capello et al. 2003, Shah et al. 2009). Registry data from Norway and Finland also indicate that certain HA-coated stems have excellent survivorship up to 10 years (Eskelinen et al. 2006, Hallan et al. 2007, Makela et al. 2008).On the other hand, a number of studies on stem survival in the setting of randomized trials or smaller observational studies have failed to show beneficial effects of HA coating on clinical outcome and implant survival when compared to alternatives such as porous coating and sand-blasted rough surfaces (McPherson et al. 1995, Tanzer et al. 2001, Kim et al. 2003, Parvizi et al. 2004, Sanchez-Sotelo et al. 2004). Meta-analyses that have pooled data from randomized or cohort studies have come to the conclusion that there is “[…] no clinically beneficial effect to the addition of HA to porous coating alone in primary uncemented hip arthroplasty” (Gandhi et al. 2009, Li et al. 2013). In addition, a Danish registry analysis found that the use of HA coating does not reduce the risk of stem revision (Paulsen et al. 2007). Furthermore, a comparison of 4,772 uncemented Bimetric stems with or without HA coating implanted between 1992 and 2009 did not reveal any difference in survival between the 2 variants (Lazarinis et al. 2011).HA was initially introduced as an implant coating to speed up and facilitate ongrowth and ingrowth of bone and thereby improve fixation, based on comprehensive preclinical and promising clinical documentation (Geesink et al. 1987, Bauer et al. 1991, Overgaard et al. 1997, Karrholm et al. 1998). Later on, concerns were raised due to findings of delamination and generation of HA particles originating from the coating with the potential to trigger osteolysis, acceleration of polyethylene wear, and subsequent implant loosening (Bloebaum and Dupont 1993, Morscher et al. 1998, Lazarinis et al. 2010). Today, there is renewed interest in HA coatings due to possible properties as a carrier for agents aimed at preventing infection (Ghani et al. 2012). Theoretical arguments for and against the use of HA coating can therefore be found. Given the renewed interest in uncemented stems—instigated by favorable outcomes after uncemented stem fixation in younger patients—the question of whether HA coating is beneficial or not is highly relevant (Eskelinen et al. 2006, Hooper et al. 2009, Swedish Hip Arthroplasty Register 2011). We therefore investigated uncemented stems with and without HA coating that are in frequent use in the Nordic countries, regarding early and long-term survival.     

Range of motion and strength after surgery for brachial plexus birth palsy

Background

There is little information about the range of motion (ROM) and strength of the affected upper limbs of patients with permanent brachial plexus birth palsy.

Patients and methods

107 patients who had brachial plexus surgery in Finland between 1971 and 1998 were investigated in this population-based, cross-sectional, 12-year follow-up study. During the follow-up, 59 patients underwent secondary procedures. ROM and isometric strength of the shoulders, elbows, wrists, and thumbs were measured. Ratios for ROM and strength between the affected and unaffected sides were calculated.

Results

61 patients (57%) had no active shoulder external rotation (median 0° (-75–90)). Median active abduction was 90° (1–170). Shoulder external rotation strength of the affected side was diminished (median ratio 28% (0–83)). Active elbow extension deficiency was recorded in 82 patients (median 25° (5–80)). Elbow flexion strength of the affected side was uniformly impaired (median ratio 43% (0–79)). Median active extension of the wrist was 55° (-70–90). The median ratio of grip strength for the affected side vs. the unaffected side was 68% (0–121). Patients with total injury had poorer ROM and strength than those with C5–6 injury. Incongruity of the radiohumeral joint and avulsion were associated with poor strength values.

Interpretation

ROM and strength of affected upper limbs of patients with surgically treated brachial plexus birth palsy were reduced. Patients with avulsion injuries and/or consequent joint deformities fared worst.Most brachial plexus birth palsy (BPBP) patients (66–92%) recover spontaneously (Michelow et al. 1994, Noetzel et al. 2001, Hoeksma et al. 2004, Pöyhiä et al. 2010). Indications for brachial plexus surgery vary (Kay 1998, Rust 2000, O''Brian et al. 2006). However, severe total injury or upper-middle plexus injury with no signs of spontaneous recovery within 3–6 months is widely accepted as an indication for early operative treatment (Gilbert et al. 1988, Clarke and Curtis 1995, Strömbeck et al. 2000, Smith et al. 2004).The severity of neural involvement in BPBP varies from transient neurapraxia to avulsion-type root injuries. Upper plexus (C5-6) injury affects shoulder and elbow function. Furthermore, wrist function is affected to varying degrees in more extensive injuries that involve the upper and middle plexus (C5-7). In total injuries (C5-T1), finger function is also compromised (Bager 1997, Sheburn et al. 1997).Muscle weakness and joint contractures of the affected upper limb are common in patients with permanent BPBP (Zancolli 1981, Waters et al. 1998, Hoeksma et al. 2003, Kirjavainen et al. 2007, Strömbeck et al. 2007). Muscle imbalance in BPBP patients can lead to soft tissue contractures and eventually to joint deformities (Pollock and Reed 1989, Waters et al. 1998, Nath et al. 2007). There is a negative correlation between degree of osseous deformity of the glenohumeral joint and shoulder range of motion (ROM) (Hoeksma et al. 2003, Kozin 2004).In this population-based, cross–sectional, long-term follow-up study, we assessed ROM and isometric maximal muscle strength of the upper limbs of surgically treated BPBP patients.     

Comparison of flanged and unflanged acetabular cup design: An experimental study using ceramic and cadaveric acetabuli

Background and purpose

Adequate depth of cement penetration and cement mantle thickness is important for the durability of cemented cups. A flanged cup, as opposed to unflanged, has been suggested to give a more uniform cement mantle and superior cement pressurization, thus improving the depth of cement penetration. This hypothesis was tested experimentally.

Materials and methods

The same cup design with and without flange (both without cement spacers) was investigated regarding intraacetabular pressure, cement mantle thickness, and depth of cement penetration. With machine control, the cups were inserted into open-pore ceramic acetabular models (10 flanged, 10 unflanged) and into paired cadaver acetabuli (10 flanged, 10 unflanged) with prior pressurization of the cement.

Results

No differences in intraacetabular pressures during cup insertion were found, but unflanged cups tended to migrate more towards the acetabular pole. Flanged cups resulted in thicker cement mantles because of less bottoming out, whereas no differences in cement penetration into the bone were observed.

Interpretation

Flanged cups do not generate higher cementation pressure or better cement penetration than unflanged cups. A possible advantage of the flange, however, may be to protect the cup from bottoming out, and there is possibly better closure of the periphery around the cup, sealing off the cement-bone interface.The main cause of aseptic loosening is inadequate surgical techniques and inferior prosthetic implants (Herberts and Malchau 2000). Sufficient cement penetration (3–5 mm) into cancellous bone and prevention of bottoming out of the cup, as seen from a uniform cement mantle that is at least 2 mm thick (i.e. cement penetration excluded), have been said to be crucial for cup fixation (Huiskes and Slooff 1981, Noble and Swarts 1983, Schmalzried et al. 1993, Mjöberg 1994, Ranawat et al. 1997, Lichtinger and Muller 1998). A clean bony surface with partly exposed cancellous bone together with cement pressurization before prosthetic implantation improves the depth of cement penetration, thus creating a stronger cement-bone interface (Krause et al. 1982, Rey, Jr. et al. 1987, Mann et al. 1997, Flivik et al. 2006, Abdulghani et al. 2007).Absence of postoperative demarcation at the acetabular cement-bone interface has been related to a reduced risk of aseptic cup loosening (Ranawat et al. 1995, Garcia-Cimbrelo et al. 1997, Ritter et al. 1999, Flivik et al. 2005). The use of a flanged polyethylene cup has demonstrated both less postoperative demarcation at the above interface (Hodgkinson et al. 1993) and less loosening (Garellick et al. 2000). This may be due to its ability to increase cement pressurization at the time of implantation and thereby the depth of cement penetration, though conflicting experimental findings have been reported (Oh et al. 1985, Shelley and Wroblewski 1988, Parsch et al. 2004, Lankester et al. 2007). The previous studies addressing the use of flanged cups have all had cups inserted without prior pressurization of cement, and only Parsch et al. (2004) implanted the cup into a porous material (cadaveric bone).Accordingly, we decided to compare the intraacetabular pressures, cement mantle thickness, and depth of cement penetration obtained using flanged and unflanged cups inserted in an open-pore ceramic acetabular model as well as in paired cadaveric acetabuli, using pressurization of the cement before implantation.     

Posttraumatic midshaft clavicular shortening does not result in relevant functional outcome changes: Observations in 32 healed,nonoperatively treated fractures

Background and purpose

Shoulder function may be changed after healing of a nonoperatively treated clavicular fracture, especially in cases of clavicular shortening or mal-union. We investigated scapular orientations and functional outcome in healed clavicular fractures with and without clavicular shortening.

Patients and methods

32 participants with a healed nonoperatively treated midshaft clavicular fracture were investigated. Motions of the thorax, arm, and shoulder were recorded by standardized electromagnetic 3D motion tracking. The DASH score and Constant-Murley score were used to evaluate functional outcome. Orientation of the scapula and humerus at rest and during standardized tasks, and strength and function of the affected shoulders were compared with corresponding values for the uninjured contralateral shoulders.

Results

Mean clavicular shortening was 25 mm (SD 16). Scapula protraction had increased by mean 4.4° in rest position in the affected shoulders. During abduction, slightly more protraction, slightly more lateral rotation, and slightly less backward tilt was found for the affected shoulders. For anteflexion, the scapular orientations of the affected shoulders also showed slightly increased protraction, slightly increased lateral rotation, and slightly reduced backward tilt. Scapulohumeral kinematics, maximum humerus angles, and strength were not associated with the degree of clavicular shortening. All participants had excellent performance on the Constant-Murley score and DASH score.

Interpretation

Scapulohumeral kinematics in shoulders with a healed clavicular fracture differ from those in uninjured shoulders, but these changes are small, do not result in clinically relevant changes in outcome, and do not relate to the amount of clavicular shortening. These findings do not support routine operative reduction and fixation of shortened midshaft clavicular fractures based on the argument of functional outcome.Displaced midshaft clavicular fractures are often treated nonoperatively with good results, despite the frequent presence of initial clavicular shortening (Eskola et al. 1986, Nordqvist and Petersson 1994, Robinson 1998, Hillen et al. 2010). Studies on clinical outcome after clavicular shortening have given conflicting results: some have shown shortening to be associated with poor functional outcome (Eskola et al. 1986, Hill et al. 1997, Lazarides and Zafiropoulos 2006), whereas others have indicated no such relationship (Nordqvist et al. 1997, Oroko et al. 1999, Nowak et al. 2005, Rasmussen et al. 2011). Mal-union of the clavicle leads to an altered position of the scapula relative to the thorax (Ledger et al. 2005, Veeger and van der Helm 2007), which may cause shoulder problems such as acromioclavicular osteoarthritis, reduced arm-shoulder functionality, and symptomatic winging of the scapula (Ledger et al. 2005, Hillen et al. 2012, Ristevski et al. 2013). Primary operative treatment may therefore be preferred in patients with substantial clavicular shortening (Canadian Orthopaedic Trauma Society 2007), or to prevent non-union (McKee et al. 2012). Operative treatment of clavicular midshaft fractures has become more common (Stegeman et al. 2013). However, the influence of shortening on clavicular and scapulohumeral movement and on functional outcome has not been sufficiently studied to substantiate the need for primary operative reduction and fixation of displaced clavicular fractures in order to prevent poor functional outcome.Our main goal was to assess scapular orientation and arm-shoulder kinematics in patients with healed nonoperatively treated midshaft clavicular fracture, and to compare this to their uninjured contralateral shoulder. A secondary goal was to assess the relationship between clavicular shortening and scapular orientation, and between clavicular shortening and functional outcome.     

Corticosteroid administration within 2 weeks after renal transplantation affects the incidence of femoral head osteonecrosis

Background and purpose

It has been suggested that avascular osteonecrosis (AVN) of the femoral head occurs early after systemic steroid administration. The purpose of this study was to investigate the risks regarding development of AVN at a very early stage after renal transplantation.

Methods

The presence or absence of AVN was determined by MRI at 4 weeks, at 6–12 weeks, at 24 weeks, and at 12 months after renal transplantation in 286 patients (183 males) with a mean age of 39 (16–65) years. The relationship between AVN and age, sex, absence or presence of acute rejection (AR), type of transplanted kidney (living or cadaveric), type of immune suppressor, and total dose of orally administered steroids given in the 2-week period after transplantation was investigated.

Results

There were no statistically significant correlations between the development of AVN and age, sex, absence or presence of AR, type of transplanted kidney, or type of immune suppressor. A significant dose-response relationship was found between development of AVN and the total dose of steroid administered in the first 2 weeks after surgery.

Interpretation

We found a relationship between AVN development and steroid dose in the early postoperative period, and we also showed a dose-response relationship.Avascular osteonecrosis (AVN) of the femoral head is one of the major complications of renal transplantation. It is known to develop in the early postoperative phase in 3–40% of patients (Hawkins et al. 1974, Pierides et al. 1975, Tuncay et al. 1998, Veenstra et al. 1999, Takao et al. 2011). The total steroid dose within 3 weeks postoperatively (Harrington et al. 1971), the total dose within 3 months postoperatively (Pierides et al. 1975), the total dose within the first year postoperatively, and the average daily dose (Tang et al. 2000) have been reported to contribute to the development of AVN. In addition, it has been reported that the incidence of acute rejection (AR) after renal transplantation is related to AVN development (Harrington et al. 1971, Tang et al. 2000). Development of AVN was found to be less frequent in a group that received tacrolimus than in a group that received cyclosporine (Sakai et al. 2003, Abbott et al. 2005).In patients who have undergone renal transplantation, T1-weighted MRI shows a band pattern in the femoral head at around 6–12 weeks postoperatively (Kubo et al. 1997, Fujioka et al. 2001). This indicates that AVN occurs very early after renal transplantation. MRI has been reported to have high sensitivity and specificity for the diagnosis of AVN (Sugano et al. 1999), and should be used for precise assessment of AVN development. Only a few reports have used MRI to determine the risk of AVN development in the early period after renal transplantation; this includes studies that have shown statistically significant relationships (1) between AVN development and total dose of steroid within 2 months postoperatively (Shibatani et al. 2008), and (2) between AVN development and delayed renal function (Takao et al. 2011).We wanted to determine the risks regarding development of femoral head AVN at an earlier stage than those evaluated in previous studies after renal transplantation.     

Persistent pain is common 1–2 years after shoulder replacement: A nationwide registry-based questionnaire study of 538 patients

Results 538 patients were available for analysis. The prevalence of persistent pain was 22% (CI: 18–25), and the prevalence of presumed neuropathic pain was 13% (CI: 10–16). Persistent pain was more frequent in fracture patients (29%) than in osteoarthritis patients (16%), while the prevalence of neuropathic pain was similar. Severe pain during the first postoperative week increased the risk of persistent pain. Risk also increased with hemiprosthesis (as compared to total prosthesis) in osteoarthritis patients, and with previous osteosynthesis and pain elsewhere in fracture patients.Interpretation Persistent pain after shoulder replacement is a daily burden for many patients. Further studies should address patient and prosthesis selection, postoperative pain management, and follow-up of these patients.There is a substantial amount of literature documenting that there is a possible risk of persistent pain after almost any surgical procedure (Macrae 2001, Johansen et al. 2012). The prevalence rates are highly dependent on the type of surgery, and vary from 5% to 85% (Kehlet et al. 2006, Macrae 2008). The consequences of chronic or persistent postsurgical pain are significant, not only in terms of suffering and reduced quality of life for the individual patient, but also with regard to the subsequent costs to healthcare services and social services. Many authors have reported putative risk factors for persistent pain, including genetic factors, age, psychosocial factors, type of anesthesia, pain elsewhere than the surgical site, other comorbidities, preoperative pain, and acute postoperative pain (Althaus et al. 2012, VanDenKerkhof et al. 2013). Intraoperative nerve damage and the extent of surgery are also important risk factors (Katz and Seltzer 2009). In fact, many patients with persistent postsurgical pain present with characteristic symptoms of neuropathic pain in the affected area (Kehlet et al. 2006).There is a scarcity of data on persistent postsurgical pain after orthopedic surgery. To our knowledge, previous studies focusing on persistent postsurgical pain in orthopedic patients have concerned mainly amputation or hip or knee replacement (Nikolajsen et al. 2006, Lundblad et al. 2008, Beswick et al. 2012, Liu et al. 2012, Jansen et al. 2014). Trials of shoulder replacement surgery have more commonly reported pain relief, or a composite score including pain, rather than the prevalence of pain at follow-up. There has been very little research on predictive factors for persistent postsurgical pain following shoulder replacement, but the general outcome has been shown to be associated with diagnosis and prosthesis type (Radnay et al. 2007, Fevang et al. 2013) and with previous shoulder surgery, age, and preoperative Short Form-36 mental score and DASH functional score (Simmen et al. 2008). Identification of subgroups at increased risk is important in order to establish interventions to prevent or minimize the impact of persistent postsurgical pain.We investigated the prevalence of, the characteristics of, and risk factors for persistent pain 1–2 years after more than 500 shoulder replacements performed in Denmark.