Results of Revision Surgery and Causes of Unstable Total Knee Arthroplasty

Background

The aim of this study was to evaluate causes of unstable total knee arthroplasty and results of revision surgery.

Methods

We retrospectively reviewed 24 knees that underwent a revision arthroplasty for unstable total knee arthroplasty. The average follow-up period was 33.8 months. We classified the instability and analyzed the treatment results according to its cause. Stress radiographs, postoperative component position, and joint level were measured. Clinical outcomes were assessed using the Hospital for Special Surgery (HSS) score and range of motion.

Results

Causes of instability included coronal instability with posteromedial polyethylene wear and lateral laxity in 13 knees, coronal instability with posteromedial polyethylene wear in 6 knees and coronal and sagittal instability in 3 knees including post breakage in 1 knee, global instability in 1 knee and flexion instability in 1 knee. Mean preoperative/postoperative varus and valgus angles were 5.8°/3.2° (p = 0.713) and 22.5°/5.6° (p = 0.032). Mean postoperative α, β, γ, δ angle were 5.34°, 89.65°, 2.74°, 6.77°. Mean changes of joint levels were from 14.1 mm to 13.6 mm from fibular head (p = 0.82). The mean HSS score improved from 53.4 to 89.2 (p = 0.04). The average range of motion was changed from 123° to 122° (p = 0.82).

Conclusions

Revision total knee arthroplasty with or without a more constrained prosthesis will be a definite solution for an unstable total knee arthroplasty. The solution according to cause is very important and seems to be helpful to avoid unnecessary over-constrained implant selection in revision surgery for total knee instability.     

Minimally invasive percutaneous osteosynthesis for proximal humeral shaft fractures with the PHILOS through the deltopectoral approach

Purpose

The aim of this study was to evaluate clinical outcomes and complications following minimally invasive plate osteosynthesis (MIPO) with the proximal humeral internal locking system (PHILOS) for treating proximal humeral shaft fracture through the deltopectoral approach.

Methods

Between November 2008 and March 2010, 74 patients with unilateral proximal humeral shaft fractures were treated using the MIPO technique with the PHILOS through the deltopectoral approach. Patients received an average follow-up of 16.9 (range, 12–24) months, and the final follow-up included anteroposterior and lateral imaging and recording of postoperative complications. The Constant–Murley shoulder score was used to evaluate function.

Results

No intraoperative complications occurred. Postoperative complications included subacromial impingement in four patients. There was no deep infection, neurovascular damage, breakage or implant loosening. All fractures united in an average time of 17.4 (15–25) weeks. In terms of function, the Constant–Murley score was 85.8 points on average (range, 67–100). The range of motion of the involved shoulder was satisfactory, and pain-free in 83.8 % of patients.

Conclusions

Using the MIPO technique with the PHILOS through the deltopectoral approach is a valid and safe method of treating proximal humeral shaft fractures.     

Can the Ream and Run Procedure Improve Glenohumeral Relationships and Function for Shoulders With the Arthritic Triad?

Background

The arthritic triad of glenoid biconcavity, glenoid retroversion, and posterior displacement of the humeral head on the glenoid is associated with an increased risk of failure of total shoulder joint replacement. Although a number of glenohumeral arthroplasty techniques are being used to manage this complex pathology, problems with glenoid component failure remain. In that the ream and run procedure manages arthritic pathoanatomy without a glenoid component, we sought evidence that this procedure can be effective in improving the centering of the humeral head contact on the glenoid and in improving the comfort and function of shoulders with the arthritic triad without the risk of glenoid component failure.

Questions/purposes

We asked, for shoulders with the arthritic triad, whether the ream and run procedure could improve glenohumeral relationships as measured on standardized axillary radiographs and patient-reported shoulder comfort and function as recorded by the Simple Shoulder Test.

Methods

Between January 1, 2006 and December 14, 2011, we performed 531 primary anatomic glenohumeral arthroplasties for arthritis, of which 221 (42%) were ream and run procedures. Of these, 30 shoulders in 30 patients had the ream and run procedure for the arthritic triad and had two years of clinical and radiographic follow-up. These 30 shoulders formed the basis for this case series. The average age of the patients was 56 ± 8 years; all but one were male. Two of the 30 patients requested revision to total shoulder arthroplasty within the first year after their ream and run procedure because of their dissatisfaction with their rehabilitation progress. For the 28 shoulders not having had a revision, we determined on the standardized axillary views before and after surgery the glenoid type, glenoid version (90° minus the angle between the plane of the glenoid face and the plane of the body of the scapula), and location of the humeral contact point with respect to the anteroposterio dimension of the glenoid (the ratio of the distance from the anterior glenoid lip to the contact point divided by the distance between the anterior and posterior glenoid lips). We also recorded the patient’s self-assessed shoulder comfort and function before and after surgery using the 12 questions of the Simple Shoulder Test.

Results

For the 28 unrevised shoulders the mean followup was 3.0 years (range, 2–9.2 years). In these patients, the ream and run procedure resulted in improved centering of the humeral head on the face of the glenoid (preoperative: 75% ± 7% posterior; postoperative: 59% ± 10% posterior; mean difference 16% [95% CI, 13%–19%]; p < 0.001), notably this improved centering was achieved without a significant change in the glenoid version. Patient-reported function was improved (preoperative Simple Shoulder Test: 5 ± 3, postoperative Simple Shoulder Test: 10 ± 4, mean difference 5 [95% CI, 4–6], p < 0.001).

Conclusions

For shoulders with the arthritic triad, the ream and run procedure can provide improvement in humeral centering on the glenoid and in patient-reported shoulder comfort and function without the risk of glenoid component failure. In that ream and run is a new procedure, substantial additional clinical research with long-term follow-up is needed to define specifically the shoulder characteristics, the patient characteristics and the technical details that are most likely to lead to durable improvements in the comfort and function of shoulders with the challenging pathology known as the arthritic triad.

Level of Evidence

Level IV, therapeutic study.     

Revision knee arthroplasty with a rotating-hinge design in elderly patients with instability following total knee arthroplasty

Background

Revision knee arthroplasty with a rotating-hinge design could be an option for the treatment of instability following total knee arthroplasty (TKA) in elderly patients.

Purpose

To evaluate the clinical and radiographic results of revision arthroplasties in TKAs with instability using a rotating-hinge design in elderly patients.

Methods

We retrospectively reviewed 96 rotating-hinge arthroplasties. The average age of the patients was 79 years (range, 75–86 years); the minimum follow-up was 5 years (mean, 7.3 years; range, 5–10 years). Patients were evaluated clinically (Knee Society score) and radiographically (position of prosthetic components, signs of loosening, bone loss).

Results

At a minimum followup of 5 years (mean, 7.3 years; range, 5–10 years), Knee Society pain scores improved from 37 preoperatively to 79 postoperatively, and function scores improved from 34 to 53. ROM improved on average from −15° of extension and 80° of flexion before surgery to −5° of extension and 120° of flexion at the last followup (p = 0.03). No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in 2 knees. One patient required reoperation because of a periprosthetic infection.

Conclusions

Revision arthroplasty with a rotating-hinge design provided substantial improvement in function and a reduction in pain in elderly patients with instability following TKA.

Level of evidence

Level IV, therapeutic study.     

Implant Design Variations in Reverse Total Shoulder Arthroplasty Influence the Required Deltoid Force and Resultant Joint Load

Background

Reverse total shoulder arthroplasty (RTSA) is widely used; however, the effects of RTSA geometric parameters on joint and muscle loading, which strongly influence implant survivorship and long-term function, are not well understood. By investigating these parameters, it should be possible to objectively optimize RTSA design and implantation technique.

Questions/purposes

The purposes of this study were to evaluate the effect of RTSA implant design parameters on (1) the deltoid muscle forces required to produce abduction, and (2) the magnitude of joint load and (3) the loading angle throughout this motion. We also sought to determine how these parameters interacted.

Methods

Seven cadaveric shoulders were tested using a muscle load-driven in vitro simulator to achieve repeatable motions. The effects of three implant parameters—humeral lateralization (0, 5, 10 mm), polyethylene thickness (3, 6, 9 mm), and glenosphere lateralization (0, 5, 10 mm)—were assessed for the three outcomes: deltoid muscle force required to produce abduction, magnitude of joint load, and joint loading angle throughout abduction.

Results

Increasing humeral lateralization decreased deltoid forces required for active abduction (0 mm: 68% ± 8% [95% CI, 60%–76% body weight (BW)]; 10 mm: 65% ± 8% [95% CI, 58%–72 % BW]; p = 0.022). Increasing glenosphere lateralization increased deltoid force (0 mm: 61% ± 8% [95% CI, 55%–68% BW]; 10 mm: 70% ± 11% [95% CI, 60%–81% BW]; p = 0.007) and joint loads (0 mm: 53% ± 8% [95% CI, 46%–61% BW]; 10 mm: 70% ± 10% [95% CI, 61%–79% BW]; p < 0.001). Increasing polyethylene cup thickness increased deltoid force (3 mm: 65% ± 8% [95% CI, 56%–73% BW]; 9 mm: 68% ± 8% [95% CI, 61%–75% BW]; p = 0.03) and joint load (3 mm: 60% ± 8% [95% CI, 53%–67% BW]; 9 mm: 64% ± 10% [95% CI, 56%–72% BW]; p = 0.034).

Conclusions

Humeral lateralization was the only parameter that improved joint and muscle loading, whereas glenosphere lateralization resulted in increased loads. Humeral lateralization may be a useful implant parameter in countering some of the negative effects of glenosphere lateralization, but this should not be considered the sole solution for the negative effects of glenosphere lateralization. Overstuffing the articulation with progressively thicker humeral polyethylene inserts produced some adverse effects on deltoid muscle and joint loading.

Clinical Relevance

This systematic evaluation has determined that glenosphere lateralization produces marked negative effects on loading outcomes; however, the importance of avoiding scapular notching may outweigh these effects. Humeral lateralization’s ability to decrease the effects of glenosphere lateralization was promising but further investigations are required to determine the effects of combined lateralization on functional outcomes including range of motion.     

Future Patient Demand for Shoulder Arthroplasty by Younger Patients: National Projections

Background

The outcomes of shoulder arthroplasties in younger patients (55 years or younger) are not as reliable compared with those of the general population. Greater risk of revision and higher complication rates in younger patients present direct costs to the healthcare system and indirect costs to the patient in terms of quality of life. Previous studies have suggested an increased demand for shoulder arthroplasties overall, but to our knowledge, the demand in younger patients has not been explored.

Questions/purposes

We asked: (1) What was the demand for shoulder arthroplasties between 2002 and 2011 in the United States for all patients and a specific subpopulation of patients who were 55 years old or younger? (2) How is the demand for shoulder arthroplasties in younger patients projected to change through 2030? (3) How is procedural demand projected to change in younger patients through 2030, and specifically, what can we anticipate in terms of hemiarthroplasty volume compared with that of total shoulder arthroplasty?

Methods

We used the National Inpatient Sample database to identify primary shoulder arthroplasties performed between 2002 and 2011. A Poisson regression model was developed using the National Inpatient Sample data and United States Census Bureau projections on future population changes to predict estimated national demand for total shoulder arthroplasties and hemiarthroplasties in all patients and in the subpopulation 55 years old or younger. This model was projected until 2030, with associated 95% CIs. We then specifically analyzed the projected demand of hemiarthroplasties and compared this with demand for all arthroplasty procedures in the younger patient population.

Results

Demand for shoulder arthroplasties in patients 55 years or younger is increasing at a rate of 8.2% per year (95% CI, 7.06%–9.35%), compared with a growth rate of 12.1% (95% CI, 8.35%–16.02%) per year for patients older than 55 years. In 2002, 15.9% (3587 of 22,617 captured in the National Inpatient Sample) of primary shoulder arthroplasties were performed in patients 55 years old or younger. In 2011, the relative size of the younger patient population had decreased to 11.0% (7001 of 63,784) of all recipients of shoulder arthroplasties. The demand for primary shoulder arthroplasties among younger patients is projected to increase by 333.3% (95% CI, 257.0%–432.5%) from 2011 to 2030. However, in patients older than 55 years demand is projected to increase by 755.4% (95% CI, 380.7%–1511.1%). Therefore, despite the increased predicted demand for shoulder arthroplasties in younger patients, they are predicted to account for only 4% of all recipients by 2030. The rate of hemiarthroplasties in patients 55 years or younger showed a 16.5% decline per year (95% CI, 16.1%–17.1%) from 2002 (53.6% of all arthroplasties) to 2011 (34.2% of all arthroplasties). By 2030, hemiarthroplasties are projected to account for only 23.5% of all shoulder arthroplasties in patients 55 years or younger.

Conclusions

The demand for shoulder arthroplasties in younger patients continues to increase in the United States; however, rates of hemiarthroplasties are declining. The demand has substantial implications for future revision arthroplasties, which include the direct healthcare costs of revision arthroplasty, the indirect societal burden of missed productivity owing to time away from work, and the increased burden of the need for qualified surgeons to meet the demand. Despite the increasing rate of arthroplasties performed in younger patients, current and projected demands remain greater for older patients, indicating a disproportionately greater need for shoulder arthroplasties in older patients. This is in contrast to the trends observed in the literature regarding hip and knee arthroplasties that show projected demands to be greater in younger patients. Factors responsible for the difference in demand require further investigation but may be related to changing indications, reported poorer outcomes in younger patients, the increased popularity of reverse shoulder arthroplasties in the elderly, or the evolution of nonarthroplasty options.

Level of Evidence

Level III, prognostic study.     

What Are Risk Factors for Intraoperative Humerus Fractures During Revision Reverse Shoulder Arthroplasty and Do They Influence Outcomes?

Background

With the increase in shoulder arthroplasty rates, the number of perioperative complications, such as periprosthetic fractures, continues to be a rise; however, the risk factors and incidence of intraoperative complications, such as fractures, during revision reverse shoulder arthroplasty are not well established.

Questions/purposes

We evaluated patients receiving a reverse shoulder arthroplasty to determine (1) the frequency and characteristics of intraoperative humerus fractures, (2) the risk factors for fracture, (3) the complications associated with treatment of fractures, and (4) clinical and functional outcomes after treatment.

Methods

Using one institution’s total joint registry, we performed a retrospective analysis of medical records of 224 patients (230 shoulders) who underwent revision surgery to reverse shoulder arthroplasty, from 2005 to 2012, for failed total shoulder arthroplasty. Reverse shoulder arthroplasty was used when there was a deficient rotator cuff, prior instability, or deficient glenoid bone stock. Intraoperative periprosthetic humerus fractures occurred in 36 shoulders (16%) (36 patients). The clinical outcome analysis included 29 patients with a minimum 2-year clinical followup (mean followup, 3.1 years; range, 2.0−6.3 years). The control group consisted of 188 patients (194 shoulders), and it was used for risk-factor calculation; whereas only 150 patients (154 shoulders) in the control group had a minimum 2-year followup, and thus only 150 patients (154 shoulders) made up the comparators (controls) for outcome-analysis comparisons. Risk factors were assessed using univariate analysis with odds ratios (OR), whereas implant survival and complications were assessed using the Kaplan-Meier method.

Results

Three displaced and 33 nondisplaced fractures occurred during revision reverse total shoulder arthroplasties. Most of the fractures (81%) occurred during component removal of cemented (n = 11) and cementless (n = 25) components. Intraoperative fractures only were treated with stabilization of the prosthetic stem in 28 patients, while adjunctive internal fixation was used in eight patients. Risk of intraoperative periprosthetic fractures was increased by factors including female sex (n =18 women; OR, 2.41; range, 1.11−5.68; p = 0.03); history of instability (n = 27; OR, 2.65; range, 1.18−5.93; p = 0.02); and prior hemiarthroplasty (n = 22; OR, 2.34; range, 1.13−4.84; p = 0.03). There were two postoperative fractures in patients who had an intraoperative fracture and both were treated nonoperatively. Overall, three (8%) revision procedures were performed in patients with intraoperative fractures, with 2- and 5-year survivorship estimates of 94% and 85%, respectively, compared with 89% and 84%, respectively for patients without an intraoperative fracture (p = 0.45). At latest followup, patients experienced good postoperative pain relief, improved shoulder abduction, and good American Shoulder and Elbow Surgeon and Simple Shoulder Test scores.

Conclusions

Intraoperative humeral fractures occur in approximately 16% of shoulders undergoing revision surgery. Fractures during revision reverse TSA are not uncommon secondary to the risks of component removal in revision surgery and poor remaining bone stock. The risk seems to be greatest for female patients, patients with instability, and patients who have undergone previous hemiarthroplasties. Intraoperative humeral fractures should be approached in a systematic way to achieve anatomic reduction and stable fixation. When properly stabilized, these fractures appear not to substantially influence overall final outcome. This study provides a foundation for future investigation of methods to reduce the risk for intraoperative humeral fractures attributable to reverse revision TSA.

Level of Evidence

Level III, therapeutic study.     

Closed retrograde multiple intramedullary Kirschner wires fixation for humeral shaft fractures with the limb flexed over an articulated support

Objective

To evaluate the results of multiple closed intramedullary Kirschner wiring via a supracondylar entry point for humeral shaft fractures.

Patients and methods

The charts of 37 patients with humeral shaft fractures treated with the Hackethal''s technique between January 2007 and December 2011 were reviewed retrospectively. The operation was performed with the patient lying in supine (n = 22) or lateral (n = 15) position. The elbow was flexed over an articulated support with the arm kept in a vertical position. Thirty-three patients were available for final evaluation with a mean follow-up delay of 14 (range, 6–24) months. We were concerned about fracture union, range of motion of the shoulder and the elbow, and complications. Final evaluation used the criteria by Qidwai.

Results

Bone union rate was 94%. Restriction of ranges of motion of the shoulder more than 20° was noticed in two patients due to protruding wires. Three patients developed limitation of elbow extension owing to backing out of the wires. The overall results were excellent (n = 26; 79%), good (n = 4; 12%), and poor (n = 3; 9%).

Conclusion

Closed Hackethal''s technique using K-wires gives satisfactory results in terms of bone union and elbow and shoulder function in selected humeral shaft fractures. The articulated support precludes the transolecranon traction.     

Anterior and Anterolateral Approaches for THA Are Associated With Lower Dislocation Risk Without Higher Revision Risk

Background

Lack of consensus continues regarding the benefit of anteriorly based surgical approaches for primary total hip arthroplasty (THA). The purpose of this study was to evaluate the risk of aseptic revision, septic revision, and dislocations for various approaches used in primary THAs from a community-based healthcare organization.

Questions/purposes

(1) What is the incidence of aseptic revision, septic revision, and dislocation for primary THA in a large community-based healthcare organization? (2) Does the risk of aseptic revision, septic revision, and dislocation vary by THA surgical approach?

Methods

The Kaiser Permanente Total Joint Replacement Registry was used to identify primary THAs performed between April 1, 2001 and December 31, 2011. Endpoints were septic revisions, aseptic revisions, and dislocations. The exposure of interest was surgical approach (posterior, anterolateral, direct lateral, direct anterior). Patient, implant, surgeon, and hospital factors were evaluated as possible confounders. Survival analysis was performed with marginal multivariate Cox models. Hazard ratios (HRs) and 95% confidence intervals (CIs) are reported. A total of 42,438 primary THAs were available for analysis of revision outcomes and 22,237 for dislocation. Median followup was 3 years (interquartile range, 1–5 years). The registry’s voluntary participation is 95%. The most commonly used approach was posterior (75%, N = 31,747) followed by anterolateral (10%, N = 4226), direct anterior (4%, N = 1851), and direct lateral (2%, N = 667).

Results

During the study period 785 hips (2%) were revised for aseptic reasons, 213 (0.5%) for septic reasons, and 276 (1%) experienced a dislocation. The revision rate per 100 years of observation was 0.54 for aseptic revisions, 0.15 for septic revisions, and 0.58 for dislocations. There were no differences in adjusted risk of revision (either septic or aseptic) across the different THA approaches. However, the anterolateral approach (adjusted HR, 0.29; 95% CI, 0.13–0.63, p = 0.002) and direct anterior approach (adjusted HR, 0.44; 95% CI, 0.22–0.87, p = 0.017) had a lower risk of dislocation relative to the posterior approach. There were no differences in any of the outcomes when comparing the direct anterior approach with the anterolateral approach.

Conclusions

Anterior and anterolateral surgical approaches had the advantage of a lower risk of dislocation without increasing the risk of early revision.

Level of Evidence

Level III, therapeutic study.     

Manipulation Under Anaesthesia for Stiffness Following Knee Arthroplasty

INTRODUCTION

Stiffness following knee arthroplasty is a frustrating complication and a significantly disabling problem. We present our experience of knee stiffness requiring manipulation under anaesthesia (MUA) as the first line of treatment following partial or total knee arthroplasty.

PATIENTS AND METHODS

All stiff knees requiring MUA over a 6-month period from March to August 2007 were retrospectively analysed from theatre records and case notes. Data were collected regarding demographics, range of knee motion before and after manipulation and at subsequent follow-up. Complications of the procedure and outcomes were also analysed.

RESULTS

Twenty-one patients (11 female, 10 male) underwent MUA. The average age was 62 years (range, 56–80 years). Sixteen primary and 3 revision total knee replacements underwent manipulation, as did one medial unicompartmental replacement and one patellofemoral arthroplasty. General anaesthesia with good muscle relaxation was used in all but one patient. The mean duration between arthroplasty and MUA was 13.2 weeks (range, 6-32 weeks). The range of knee movement improved from a mean range of 10.4–71.2° in the pre-MUA period to 2.1–94.0° post-MUA and at follow-up was 2.3–91.9°. The mean arc of motion improved from 60.2° (range, 40–80°) pre-MUA to 91.9° (range, 45–120°) post-MUA. The mean improvement in the arc of motion was 31.6° (P < 0.001). At an average follow-up of 3 months (range, 6 weeks to 8 months), the mean arc of motion was 90.4° (range, 40–120°). The mean improvement in knee movement from the pre-MUA at the follow-up was 30.2° (P < 0.001). One patient failed to gain any improvement from MUA. There were no complications noted from the procedure.

CONCLUSIONS

MUA has a role in the treatment of early stiffness with excellent immediate outcomes. We advocate that MUA should be the first line of management for stiff knee arthroplasties after failed physiotherapy.     

Latissimus Dorsi and Teres Major Transfer With Reverse Shoulder Arthroplasty Restores Active Motion and Reduces Pain for Posterosuperior Cuff Dysfunction

Background

In patients with rotator cuff dysfunction, reverse shoulder arthroplasty can restore active forward flexion, but it does not provide a solution for the lack of active external rotation because of infraspinatus and the teres minor dysfunction. A modified L’Episcopo procedure can be performed in the same setting wherein the latissimus dorsi and teres major tendons are transferred to the lateral aspect of proximal humerus in an attempt to restore active external rotation.

Questions/purposes

(1) Do latissimus dorsi and teres major tendon transfers with reverse shoulder arthroplasty improve external rotation function in patients with posterosuperior rotator cuff dysfunction? (2) Do patients experience less pain and have improved outcome scores after surgery? (3) What are the complications associated with reverse shoulder arthroplasty with latissimus dorsi and teres major transfer?

Methods

Between 2007 and 2010, we treated all patients undergoing shoulder arthroplasty who had a profound external rotation lag sign and advanced fatty degeneration of the posterosuperior rotator cuff (infraspinatus plus teres minor) with this approach. A total of 21 patients (mean age 66 years; range, 58–82 years) were treated this way and followed for a minimum of 2 years (range, 26–81 months); none was lost to followup, and all have been seen in the last 5 years. We compared pre- and postoperative ranges of motion, pain, and functional status; scores were drawn from chart review. We also categorized major and minor complications.

Results

Active forward flexion improved from 56° ± 36° to 120° ± 38° (mean difference: 64° [95% confidence interval {CI}, 45°–83°], p < 0.001). Active external rotation with the arm adducted improved from 6° ± 16° to 38° ± 14° (mean difference: 30° [95% CI, 21°–39°], p < 0.001); active external rotation with the arm abducted improved from 19° ± 25° to 74° ± 22° (mean difference: 44° [95% CI, 22°–65°], p < 0.001). Pain visual analog score improved from 8.4 ± 2.3 to 1.7 ± 2.1 (mean difference: −6.9 [95% CI, −8.7 to −5.2], p < 0.001), and Single Assessment Numeric Evaluation score improved from 28% ± 21% to 80% ± 24% (mean difference: 46% [95% CI, 28%–64%], p < 0.001). There were six major complications, five of which were treated operatively. Overall, three patients’ latissimus and teres major transfer failed based on persistent lack of external rotation.

Conclusions

In patients with posterior and superior cuff deficiency, reverse shoulder arthroplasty combined with latissimus dorsi and teres major transfer through a single deltopectoral incision can reliably increase active forward flexion and external rotation. Patients experience pain relief and functional improvement but have a high rate of complications; therefore, we recommend the procedure be limited to patients indicated for reverse who have profound external rotation loss and a high grade of infraspinatus/teres minor fatty atrophy.

Level of Evidence

Level IV, therapeutic study.     

Increased Risk of Periprosthetic Femur Fractures Associated With a Unique Cementless Stem Design

Background

Postoperative periprosthetic femur fractures are an increasing concern after primary total hip arthroplasty (THA). Identifying and understanding predisposing factors are important to mitigating future risk. Femoral stem design may be one such factor.

Questions/purposes

The goals of our study were to compare the (1) frequency of periprosthetic femur fracture and implant survivorship; (2) time to fracture in those patients who experienced periprosthetic femur fracture; and (3) predictive risk factors for periprosthetic femur fracture between a unique stem design with an exaggerated proximal taper angle and other contemporary cementless, proximally fixed, tapered stems.

Methods

We reviewed all hips in which a femoral hip component with a uniquely exaggerated proximal taper angle (ProxiLock) was implanted during primary THA at a single academic institution. That group of patients was compared with a cohort of patients who underwent primary THA during the same time interval (1995–2008) in which any other cementless, proximally fixed, tapered stem design was used. The two groups differed somewhat in terms of sex, age, and body mass index, although these differences were of unclear clinical significance. During the study, 3964 primary THAs were performed using six different designs of cementless, proximally fixed, tapered femoral hip prostheses. There were 736 stems in the ProxiLock (PL) patient group and 3228 stems in the non-ProxiLock (non-PL) group. In general, the stem highlighted in this study became the routine cementless stem used for primary THA for three arthroplasty surgeons without specific patient or radiographic indications. Periprosthetic fractures were identified within each group. The incidence, timing, type, and treatment required for each fracture were analyzed. The Kaplan-Meier method was used to determine study patient survival free of any postoperative fracture. Radiographs and the electronic medical record of each patient who sustained a fracture were reviewed. Followup was comparable between groups at all time points.

Results

The Kaplan-Meier estimate for fracture-free patient survival was worse in the PL group at all time points with survival of 98.4% (range, 97.4%–99.3%), 97.1% (range, 95.9%–98.3%), 95.4% (range, 93.8%–97.0%), and 92.6% (range, 89.6%–95.3%) at 30 days, 1 year, 5 years, and 10 years, respectively, for the PL patient group compared with 99.8% (range, 99.7%–99.9%), 99.6% (range, 99.3%–99.8%), 99.3% (range, 99.0%–99.6%), and 98.4% (range, 97.5%–99.1%) in the non-PL patient group (p < 0.001). Patients in the PL group had increased cumulative probability of both early and late fractures with cumulative probabilities of fracture of 2.5% (range, 1.3%–3.6%) at 90 days and 7.4% (range, 4.7%–10.4%) at 10 years compared with probabilities of 0.3% (range, 0.1%–0.5%) at 90 days and 1.6% (range, 0.8%–2.5%) at 10 years in the non-PL group (p < 0.001). Patients in the PL group had an increased risk of postoperative periprosthetic femur fracture (hazard ratio [HR], 5.6; 95% confidence interval [CI], 3.4–9.1; p < 0.001); fracture requiring reoperation (HR, 8.4; 95% CI, 4.4–15.9); p < 0.001); and fracture requiring stem revision (HR, 9.1; 95% CI, 4.5–18.5; p < 0.001). Age older than 60 years was also a risk factor for fracture (HR, 3.7; 95% CI, 2.1–6.4), but sex, body mass index, and preoperative diagnosis were not predictive.

Conclusions

Hips implanted with an uncemented femoral stem, which has a uniquely exaggerated proximal taper angle, had an increased risk of both early and late postoperative periprosthetic femur fracture. The majority of patients with a fracture underwent reoperation or stem revision. The unique proximal geometry, lack of axial support from the smooth cylindrical distal stem as well as resorption of the hydroxyapatite coating and poor ongrowth with subsequent subsidence may contribute to increased risk of fracture. Although this particular stem has recently been discontinued by the manufacturer, these findings are important in regard to followup care for patients with this stem implanted as well as for future cementless stem design in general.

Level of Evidence

Level III, therapeutic study.     

Outcomes after shoulder arthroplasty revision with glenoid reconstruction and bone grafting

Purpose

Extensive glenoid bone loss after failed shoulder arthroplasty represents a challenge for revision arthroplasty. Treatment options vary widely and have been a source of controversy among experts.

Methods

Between 2004 and 2010, a total of 17 patients underwent glenoid reconstruction surgery using an autologous iliac crest bone graft and secondary revision arthroplasty due to extensive glenoid bone loss after failed previous total shoulder arthroplasty. The outcomes were assessed by means of clinical examination, Constant score, and bi-plane radiography as well as pre-, postoperative and follow-up CT.

Results

Before the revision surgery, the mean Constant score was 24 ± 17 and improved to 40 ± 13 after the glenoid rebuilding and revision arthroplasty. CT imaging revealed adequate glenoid bone stock restoration with no relevant graft resorption or loosening of the glenoid. The average postoperative antero-posterior diameter of the glenoid was 28 ± 3 mm which had decreased to 25 ± 3 mm at follow-up. The average postoperative version of the glenoid was 95.7° ± 6° and had decreased to 98.5° ± 4° at follow-up. Both the glenoid version and diameter had changed significantly (P < 0.001) comparing postoperative and follow-up CT-scans.

Conclusion

Glenoid reconstruction surgery using an iliac crest bone-block autograft prior to revision arthroplasty represents a valuable salvage procedure in cases of extensive glenoid bone loss after primary shoulder arthroplasty. Sufficient glenoid bone stock restoration is indispensable for reliable fixation of glenoid components and in turn a satisfactory clinical outcome.     

Two-Stage Revision for Infected Total Knee Arthroplasty: Based on Autoclaving the Recycled Femoral Component and Intraoperative Molding Using Antibiotic-Impregnated Cement on the Tibial Side

Background

The purpose of this study was to determine the degree of infection control and postoperative function for new articulating metal-on-cement spacer.

Methods

A retrospective study of 19 patients (20 cases), who underwent a two-stage revision arthroplasty using mobile cement prosthesis, were followed for a minimum of 2 years. This series consisted of 16 women and 3 men, having an overall mean age of 71 years. During the first stage of revision, the femoral implant and all the adherent cement was removed, after which it was autoclaved before replacement. The tibial component was removed and a doughy state, antibiotic-impregnated cement was inserted on the tibial side. To achieve joint congruency, intraoperative molding was performed by flexing and extending the knee joint. Each patient was evaluated clinically and radiologically. The clinical assessments included range of motion, and the patients were scored as per the Hospital for Special Surgery (HSS) and Knee Society (KS) criteria.

Results

The mean range of knee joint motion was 70° prior to the first stage operation and 72° prior to the second stage revision arthroplasty; following revision arthroplasty, it was 113° at the final follow-up. The mean HSS score and KS knee and function scores were 86, 82, and 54, respectively, at the final follow-up. The success rate in terms of infection eradication was 95% (19/20 knees). No patient experienced soft tissue contracture requiring a quadriceps snip.

Conclusions

This novel technique provides excellent radiological and clinical outcomes. It offers a high surface area of antibiotic-impregnated cement, a good range of motion between first and second stage revision surgery for the treatment of chronic infection after total knee arthroplasty, and is of a reasonable cost.     

Rotator Cuff Fatty Infiltration and Atrophy Are Associated With Functional Outcomes in Anatomic Shoulder Arthroplasty

Background

Shoulder arthroplasty provides reliable pain relief and restoration of function. However, the effects of fatty infiltration and atrophy in the supraspinatus and infraspinatus muscles on functional outcomes are not well understood.

Questions/purposes

The purposes of this study were to (1) compare preoperative with postoperative fatty infiltration and atrophy of the supraspinatus and infraspinatus muscles after primary shoulder arthroplasty; and (2) identify any associations between these variables and outcome measures.

Methods

A retrospective analysis was undertaken of 62 patients with a mean age of 67 years (range, 34–90 years) who underwent shoulder arthroplasty. CT scans were conducted preoperatively and at 12 months postoperatively. Outcome variables included the degree of supraspinatus and infraspinatus fatty infiltration (percent fatty infiltration and Goutallier grade), muscle area (percent muscle area and Warner atrophy grade), shoulder strength, and the Western Ontario Osteoarthritis Score (WOOS), American Shoulder and Elbow Surgeons score, and Constant outcome score.

Results

Preoperatively, the mean percent fatty infiltration (FI) within the supraspinatus and infraspinatus was identical at 14%. One year after shoulder arthroplasty, both muscles had less fatty infiltration (6% and 7%, respectively; p < 0.001). Similarly, the Goutallier grade significantly improved postoperatively for the supraspinatus (p = 0.0037) and infraspinatus (p = 0.0007). Conversely, measures of muscle atrophy remained unchanged postoperatively (p > 0.251). Preoperatively, greater supraspinatus percent FI was negatively associated with preoperative shoulder strength (r = 0.37, p = 0.001) and Constant score (r = 0.38, p = 0.001). Postoperative infraspinatus percent FI was negatively associated with postoperative strength (r = 0.3, p = 0.021) and Constant score (r = 0.3, p = 0.04). Multivariable regression analysis of possible predictive factors demonstrated that preoperative supraspinatus percent muscle area (p = 0.016) and the diagnosis of osteoarthritis (p = 0.017) were associated with better followup WOOS scores, and preoperative supraspinatus strength was associated with postoperative strength (p = 0.0024). Higher degrees of preoperative percent FI were not associated with worse patient-reported outcomes postoperatively.

Conclusions

Supraspinatus and infraspinatus fatty infiltration improves after shoulder arthroplasty, whereas muscle area remains unchanged. Although further study of these variables is required, the negative associations identified between preoperative supraspinatus atrophy and the diagnosis of rheumatoid arthritis and postoperative quality-of-life outcome scores may aid the clinician in selecting the best treatment option for glenohumeral arthrosis and in the management of patient expectations.

Level of Evidence

Level III, prognostic study.     

Tantalum Cones Provide Durable Mid-term Fixation in Revision TKA

Background

Multiple studies have reported favorable short-term outcomes using tantalum cones to reconstruct massive bone defects during revision TKA. However, longer-term followup is needed to determine the durability of these reconstructions.

Questions/purposes

We wished to determine the mid-term (1) reoperation rates for septic and aseptic causes, (2) radiologic findings of osseointegration, and (3) clinical outcomes based on the Knee Society score in patients who underwent revision knee arthroplasty with tantalum cones for severe bone loss.

Methods

We retrospectively evaluated records of 18 patients (18 knees) who underwent revision knee arthroplasty with use of tantalum cones between 2005 and 2008; the primary indications for use of this approach were to reconstruct massive bone defects classified as Anderson Orthopaedic Research Institute Types 2B and 3. During this period, all defects of this type were treated with this approach and no cones were used for more-minor defects. A total of 26 cones (13 tibial and 13 femoral) were implanted. There were 12 female and six male patients with a mean age of 73 years (range, 55–84 years) at the time of revision. The indication for the revision included aseptic loosening (five patients) and second-stage reimplantation for deep infection (13 patients). Patients were followed for a mean of 6 years (range, 5–8 years). No patient was lost to followup. Clinical and radiographic outcomes were assessed with the Knee Society clinical rating system and radiographic evaluation system.

Results

There have been two reoperations for recurrent infection; at surgery, the two cones showed osseointegration. No evidence of loosening or migration of any implant was noted on the most recent radiographs. Knee Society knee scores improved from a mean of 31 points before surgery to 77 points at latest followup (p < 0.001), and function scores improved from a mean of 22 points to 65 points (p < 0.001).

Conclusions

Tantalum cones for reconstruction of massive bone defects in revision knee arthroplasty provided secure fixation with excellent results at average followup of 6 years, although this series included relatively few patients. These devices are a viable option for surgeons to use in situations with severe bone loss. Further studies with longer followups are needed to confirm the durability of these reconstructions.

Level of Evidence

Level IV, therapeutic study.     

Patients Undergoing Total Shoulder Arthroplasty on the Dominant Extremity Attain Greater Postoperative ROM

Background

Total shoulder arthroplasty (TSA) provides excellent functional outcomes and pain relief in appropriately selected patients. Although it is known to affect other shoulder conditions, the role of hand dominance after TSA has not been reported, to our knowledge.

Questions/Purposes

We asked: (1) Does TSA of the dominant arm result in greater postoperative ROM compared with TSA of the nondominant arm? (2) Does hand dominance affect validated outcome scores after TSA?

Methods

We performed a review of all patients who underwent primary TSAs between 2008 and 2011 with a minimum of 12 months followup. During that time, one surgeon performed 156 primary TSAs. One hundred twenty-seven patients met the minimum followup requirement for this analysis (81%), whereas 29 (19%) were lost to followup. Seven patients were excluded for surgical indications other than glenohumeral osteoarthritis. A total of 58 patients underwent TSA of the dominant upper extremity and 62 underwent TSA of the nondominant upper extremity. Patient demographics, preoperative and postoperative ROM, and preoperative and postoperative outcome scores, were collected from the medical records. Student’s t-tests and chi-square tests were used for analysis. Demographics and preoperative ROM did not differ between patients undergoing TSA on the dominant or the nondominant upper extremity.

Results

Dominant-arm TSAs showed greater postoperative forward elevation and external rotation. Postoperative active forward elevation in the dominant group was 151° versus 141° in the nondominant group (mean difference, 10°; 95% CI, 1°–18°; p = 0.033). Postoperative active external rotation was 61° in the dominant group, versus 51° in the nondominant group (mean difference, 10°; 95% CI, 5°–15°; p < 0.001). Active internal rotation did not differ (dominant, 52°, nondominant, 50°; mean difference, 2°; 95% CI, −3° to 7°; p = 0.419). There were no differences in postoperative VAS (dominant, 0.9, nondominant, 1.4; mean difference, 0.5; 95% CI, −0.1 to 1.1; p = 0.129), simple shoulder test (dominant, 9.8, nondominant, 9.2; mean difference, 0.5; 95% CI, −0.5 to 1.5; p = 0.278), and American Shoulder and Elbow Surgeons scores (dominant, 84, nondominant, 80; mean difference, 4; 95% CI, −2 to 10; p = 0.211).

Conclusions

Patients who underwent TSA of their dominant upper extremity had greater postoperative active forward elevation and active external rotation compared with patients who had TSA of their nondominant upper extremity. This average difference of 10° active forward elevation and active external rotation could be useful for preoperative and postoperative counseling of patients. Regardless of hand dominance, similar functional outcomes were achieved.

Level of Evidence

Level III, therapeutic study.