Does total knee joint replacement with the soft tissue balancing surgical technique maintain the natural joint line?

Introduction The outcomes of 106 total knee arthroplasties implanted using a soft tissue balancing surgical technique at one surgical centre were used to assess the accuracy maintaining the knee’s original joint line (JL). The aim of the study was to determine whether there is a shift of the presumed joint line after surgery.Materials and methods Preoperative and post-operative radiographs were compared to determine any changes in the articulation height. The preoperative distance of the fibular head to the natural joint line was measured and compared with the post-operative measurement of the fibular head to the femoral articulation line (measured on the radiograph and defined as Rxmm). Based on the actual medio-lateral dimension of the tibial metal back, the measured difference (RXmm) could be converted into true distances (in mm). The Blackburn–Peel index was assessed as an additional outcome prior to and following surgery.Results Preoperatively, the average distance from the fibular head to the joint line was 15.1 Rxmm (SD 4.3) while the post-surgical distance was 15.5 Rxmm (SD 5.6). The average deviation of the post-surgical JL in relation to the original JL amounted to 0.4 Rxmm (SD 3.7). The average deviation of the joint line converted into the true distance was −0.3 mm (with a range of −5.9 mm in distal direction to + 8.3 mm in the proximal direction). Valgus position appeared to generate rather a shift in proximal direction whereas varus deformity favours a shift in distal direction. Seven patients exhibited a deviation of more than 5 mm in either the distal or proximal direction. All of the patients of this subgroup had a preoperative anatomical abnormality including a severe malalignment, serious bone destruction or had previously undergone a high tibial osteotomy.Conclusion An exact reconstruction of the natural Joint Line is achievable when using the described soft tissue balancing surgical technique with the posterior cruciate ligament (PCL) retaining prosthesis design used in this series.     

Does the joint line matter in revision total knee replacement?

We identified 148 patients who had undergone a revision total knee replacement using a single implant system between 1990 and 2000. Of these 18 patients had died, six had developed a peri-prosthetic fracture and ten had incomplete records or radiographs. This left 114 with prospectively-collected radiographs and Bristol knee scores available for study. The height of the joint line before and after revision total knee replacement was measured and classified as either restored to within 5 mm of the pre-operative height or elevated if it was positioned more than 5 mm above the pre-operative height. The joint line was elevated in 41 knees (36%) and restored in 73 (64%). Revision surgery significantly improved the mean Bristol knee score from 41.1 (SD 15.9) pre-operatively to 80.5 (SD 15) post-operatively (p < 0.001). At one year post-operatively both the total Bristol knee score and its functional component were significantly better in the restored group than in the elevated group (p < 0.01). Overall, revision from a unicondylar knee replacement required less use of bone graft, fewer component augments, restored the joint line more often and gave a significantly better total Bristol knee score (p < 0.02) and functional score (p < 0.01) than revision from total knee replacement. Our findings show that restoration of the joint line at revision total knee replacement gives a significantly better result than leaving it unrestored by more than 5 mm. We recommend the greater use of distal femoral augments to help to achieve this goal.     

The patellofemoral joint in total knee arthroplasty: is the design of the trochlea the critical factor?

The outcome at 10 years is reported of a prospective study of 2 cohorts of total knee arthroplasties treated with (center A) or without (center B) patellar replacement. The same tibiofemoral components were used in all knees. The cohorts were demographically similar. A total of 124 patellae were treated by replacement, and 143 were treated without replacement. The clinical outcome and the patellofemoral revision rates were the same in the 2 cohorts: 1 patient required analgesia for anterior knee pain after replacement, and 1 without replacement required patellar replacement for pain. In the replaced group, patellofemoral survival on a best-case scenario was 100% at 10 years; on a worst-case scenario, 96%. One of the unreplaced patellae had been resurfaced for pain by 10 years. In view of the satisfactory and similar outcomes with and without replacement, we suggest that an appropriate design for the prosthetic trochlea, rather than the replacement or otherwise of the patella, is the main determinant of patellofemoral outcome in total knee arthroplasty. Patella replacement may be optional. Desirable trochlea design features are described.     

Do joint mobilizations assist in the recovery of lateral elbow tendinopathy? A systematic review and meta-analysis

Study DesignSystematic review.IntroductionNo consensus exists as to which are the most effective methods to treat the symptoms associated with lateral elbow tendinopathy (LET). Research has suggested that joint mobilizations may assist in the recovery of patients with LET.Purpose of the StudyTo determine if joint mobilizations are effective in improving pain, grip strength, and disability in adults with LET.MethodsSearches in 3 databases were performed to identify relevant clinical trials. Reviewers independently extracted data and assessed the methodological quality. Summary measures of quantitative data were extracted or calculated where possible. Appropriate data were pooled for meta-analysis using a random-effects model.ResultsA total of 20 studies met the inclusion criteria; 7 were included in the meta-analysis. Studies were broadly classified into 3 groups: mobilization with movement (MWM), Mill's manipulation, and regional mobilization techniques. Pooled data across all time periods demonstrated a mean effect size of 0.43 (95% confidence interval [CI]: 0.15-0.71) for MWM on improving pain rating, and 0.31 (95% CI: 0.11-0.51) for MWM on improving grip strength, 0.47 (95% CI: 0.11-0.82) for Mill's manipulation on improving pain rating. A mean effect size of ?0.01 (95% CI: ?0.27 to ?0.26) shows Mill's manipulation did not improve pain free grip strength. Functional outcomes varied considerably among studies. Pain, grip strength, and functional outcomes were improved with regional mobilizations.ConclusionThere is compelling evidence that joint mobilizations have a positive effect on both pain and/or functional grip scores across all time frames compared to control groups in the management of LET.     

Does unilateral total hip arthroplasty improve pain and function in the non-operative hip joint?

European Journal of Orthopaedic Surgery & Traumatology - Some reports suggested that the status of the opposite-side hip affects clinical outcomes of unilateral total hip arthroplasty (THA) for...     

What design factors influence wear behavior at the bearing surfaces in total joint replacements?

Bearing surface wear in total joint replacements arises from local stresses that exceed the mechanical strength of the articulating materials. Because both the tensile/compressive principal stresses and maximum shear stress near the bearing surface increase when contact stresses increase, minimizing contact stresses has been a central design goal, especially in total knees. Wear rates increase with factors such as increased sliding distance in metal-on-polyethylene bearings, or suboptimal fluid film lubrication in the case of hard-on-hard total hip implants. These factors in turn depend directly on implant design. Advanced preclinical assessment technologies such as laboratory physical simulators and finite element analyses have provided means by which the dependence of wear rate on mechanical design factors can be quantified. However, untoward complexities occurring in vivo, such as impingement or third-body challenge, can appreciably compromise wear performance even for implants that are well-designed in terms of bearing surface stress minimization.     

Normal CRP and WBC values in total hip arthroplasty (THA) with signs of loosening. Do we need a joint aspiration?

PurposeOverall Total hip arthroplasty (THA) is a very successful procedure. However, in case of complication dedicated management is required. Two major complications of THA failures are aseptic loosening (AL) and periprosthetic joint infection (PJI). The primary hypothesis of this study was that joint aspirations in patients with signs of loosening after THA are capable to detect PJI in suspected AL with negative serologic testing.MethodsIn this study a total of 108 symptomatic patients with radiographic signs of prosthetic loosening and hip pain in THA were included. Based on a standardized algorithm all patients underwent serological testing followed by joint aspiration preoperatively. Intraoperatively harvested samples were subjected to microbiological testing and served as the gold standard in differential diagnosis. Demographics, as well as the results of serologic and microbiological testing were collected from the medical records.ResultsOf the included patients 85 were finally diagnosed with an AL and 23 with PJI. Within the patients with PJI 13 (56%) patients demonstrated elevated CRP and WBC counts, as well as positive synovial cultures after joint aspiration. In ten patients (44%) diagnosed with PJI neither CRP nor WBC were abnormal.ConclusionThe diagnosis of PJI can be difficult in THA with radiographic signs of loosening. Clinical features including pain, fever, and local sings of infection are uncommon especially a long period after index operation. First-line screening testing relies on serological evaluation of CRP and WBC. However, normal CRP and WBC values cannot rule out a PJI. These cases can be detected by joint aspiration and synovial cultures reliably.     

“Meniscal” scar as a landmark for the joint line in revision total knee replacement

AIM To determine whether tissue identified at the joint line was actually remnant meniscal scar tissue or not. METHODS Nine patients undergoing revision knee surgery following informed consent had meniscal scar tissue sent to the histology department for analyses. All revisions were performed where joint line had been raised or lowered at earlier surgery. Although preoperative radiographic evaluations suggested that the joint line had been altered, intraoperatively there was scar tissue at the level of the recreated joint line. This scar tissue has traditionally been described as meniscal scar, and to identify the origins of this tissue, samples were sent for histological analyses. The tissue samples were stored in formalin, and embedded and sectioned before undergoing histochemical staining. All samples underwent macroscopic and microscopic examination by a histopathologist who was blind to the study aims. The specific features that were examined included tissue organisation, surface and central composition, cellular distribution including histiocytes, nuclear ratio and vasculature. Atypical and malignant features, inflammation and degeneration were specifically looked for. A statistical review of the study was performed by a biomedical statistician.RESULTS The histological findings for the nine patients showingthe macroscopic and microscopic findings, and the conclusion are outlined in a Table. The histological analyses were reviewed to determine whether the tissue samples were likely to be meniscal scar tissue. The response was yes(2, 22%), no(6, 67%) and maybe(1,11%) based on the conclusions. The results were yeswhen on macroscopy, firm cream tissue was identified.In these two yes samples, microscopic analyses showed organised fibrous tissue with focal degenerative areas with laminated pattern associated with histiocytes peripherally but no inflammation. The no samples were assessed macroscopically and microscopically and were deemed to have appearances representing fibrous synovial tissue and features in keeping with degenerate scar tissue or connective tissue. One sample was indeterminate and microscopically contained fibrocollagenous tissue with synovial hyperplasia. It also contained some degenerate hyalinised tissue that may represent cartilage, but the appearances were not specific. CONCLUSION Based on our pilot study, we recommend reliance on a number of markers to identify the joint line as outlined above, and to exercise caution in using the meniscalscar.     

Does the immune system play a role in loosening and osteolysis of total joint replacements?

Total joint replacement is a highly successful surgical procedure with an excellent outcome over many years. However, because this procedure is now being performed in younger patients, and because the average age of our population continues to increase, greater expectations have been placed on joint implants in the hope that they will last forever. Aseptic loosening and osteolysis of total joint replacements are the main processes limiting long-term implant survival. This paper focuses on the possible role of immunological mechanisms in the processes of loosening and osteolysis of joint replacements, with special emphasis on polymeric materials. This topic is very controversial: In vitro experiments and in vivo studies in animals and humans are reviewed and provide evidence for both sides of the debate. In some patients, immunological processes appear to be activated after a total joint replacement has been implanted. Specific materials or their by-products might function as haptens and elicit a T-lymphocyte-mediated, delayed hypersensitivity reaction. Many factors probably are important, including the genetic makeup and immune competence of the patient, prior exposure to the same or similar materials, degree of exposure (rate of generation of particles and the efficacy of clearance mechanisms), and characteristics of the particles themselves.     

Basal joint osteoarthritis of the thumb: trapeziectomy, with or without tendon interposition, or total joint arthroplasty? A prospective study

Background

There is no consensus in the literature concerning the choice of surgical procedure for thumb basal joint—trapeziometacarpal joint—osteoarthritis.

Method

Three treatments for osteoarthritis of the trapeziometacarpal joint of the thumb were compared: trapeziectomy (N = 22), trapeziectomy with ligament reconstruction and tendon interposition (LRTI) (N = 34) and a total cemented joint arthroplasty (N = 40). The mean follow-up was, respectively, 34, 26 and 26 months.

Results

There were no differences in outcome concerning pain, function and patient’s satisfaction. The DASH score demonstrated less disability in arthroplasties, but statistical significance was not reached. All patients improved in force and range of motion. The keypinch force correlated with the loss of height of the thumb. In the arthroplasty group, 40% of radiological loosening was seen.

Conclusion

Although the outcome of the three procedures was not significantly different, trapeziectomy scored the lowest in all parameters when compared with the LRTI patients. Arthroplasties were better but the high incidence of loosening is frightening for the future.     

Infection in total joint replacements. Why we screen MRSA when MRSE is the problem?

A retrospective review of MRSA screening showed that of a total of 8911 patients screened pre-operatively between May 1996 and February 2001, 83 (0.9%) had MRSA isolated from one source or another. During the same period, 115 (13.6%) of 844 positive tissue samples taken during surgery grew Staphylococcus aureus. Of these only 1 (0.01%) was reported to be methicillin-resistant (MRSA). However, a total of 366 (43.4%) isolates from tissue samples were reported as coagulase-negative staphylococci (C-NS). Of these, 312 samples were tested for methicillin sensitivity, of which 172 (55.1%) were found to be resistant. Staphylococcus epidermidis is the most prevalent and persistent species found on most skin and mucous membranes, constituting 65% to 90% of all staphylococci. Most isolates in tissue samples were found to be methicillin-resistant coagulase-negative staphylococcus (55.1%). Hence, it may be appropriate to undertake screening for methicillin-resistant Staphylococcus epidermidis in addition to that for MRSA.     

Trends in arthrodeses and total joint replacements in Foot and Ankle surgery in Germany during the past decade—Back to the fusion?

BackgroundThe goal of this study was to analyze trends in Foot and Ankle surgery in Germany during the past ten years.MethodsData of the German Federal Statistical Office from 2008 until 2018 were screened. We focused on the analysis of fusions and total joint replacements.ResultsThe total amount of the surgeries increased (+39.5%). Especially fusions like arthrodesis of the ankle (+31%) and of the MTP-1 joint (+77%) were on the rise. In 2017 60% of ankle arthrodesis were conducted in men, while 69% of MTP-1 arthrodesis were performed in women.The amount of joint replacements showed a decline during the last decade, in TAR (?39%) and in the MTP-1 (?48%).Regarding the patients age while undergoing a TAR, we observed a shift of the peak age group from 65 to 70 years in 2008 towards 55–60 years in 2017.ConclusionOur study represents actual health care reality in Germany and shows a constant increase of ankle arthritis surgeries in the last decade, while there was a massive shift regarding the ratio of TAR in favour of fusion procedures.     

Monitoring the integrity of the cement—metal interface of total joint components in vitro using acoustic emission and ultrasound

Debonding of the cement—metal interface of cemented femoral components of total hip arthroplasty has been shown from clinical and autopsy material to be a common occurrence. Experimentally, debonding has been shown to increase markedly the strains in the adjacent cement mantle. Studies of autopsy-retrieved specimens demonstrate that debonding of the cement—metal interface is a key initiating event in loosening of cemented femoral components of total hip arthroplasty. However, both the radiographic and autopsy evidence of cement—metal interfacial debonding exist after the fact, that is, after debonding has occurred. The lack of prospective data showing that debonding does indeed occur under physiologic loading and occurs prior to other forms of failure of fixation leaves uncertain the issue of debonding and its role in initiating loosening of cemented femoral components. Knowing when, where, and to what extent the cement—metal interface debonds is critical information in understanding the process of loosening of cemented femoral components. Such information would contribute to improving the durability of stems and improving cementing techniques. In this study, the two nondestructive techniques of acoustic emission and ultrasonic evaluation of the cement—metal interface of cemented femoral stems of total hip arthroplasty were combined to investigate when, where, and to what extent cement—metal debonding occurred in vitro in simulated femurs loaded physiologically in fatigue in simulated single-leg stance. Debonding of the cement—metal interface of a cemented femoral component in this model was both an initiating event and a major mechanism of compromise of the cement—metal interface. Additional acoustic emission signals arose from cracks that developed in the cement.