Reconstruction of Disrupted Extensor Mechanism After Total Knee Arthroplasty

Background

Disruption of the extensor mechanism after total knee arthroplasty (TKA) is a debilitating complication that results in extension lag, limited range of motion, difficulty in walking, frequent falls, and chronic pain. This study presents the clinical and radiographic results of reconstruction after extensor mechanism disruption in TKA patients.

Survivorship of Extensor Mechanism Allograft Reconstruction After Total Knee Arthroplasty

Background

Extensor mechanism disruption remains a devastating complication after total knee arthroplasty. The purpose of this study is to describe the outcomes of extensor mechanism allograft (EMA) reconstruction in a large single-center case series.

Evaluation of Extensor Mechanism in Revision Knee Arthroplasty

Background

The success of revision total knee arthroplasty depends on adequate exposure that does not produce complications. The purpose of this study was to compare the results of revision total knee arthroplasty between V-Y quadricepsplasty (QP) and quadriceps snip (QS) approaches.

A Rare Mode of Extensor Mechanism Failure in Total Knee Arthroplasty

We reported a rare mode of extensor mechanism failure in total knee arthroplasty. The patellar tendon was elongated and thin instead of disruption at the bone-tendon junction. We also described the surgical technique for reconstruction of patellar tendon. Patellar tendon was shortened by a precalculated amount. It was then augmented by autologous semitendinosus tendon graft and protected by tension band wire. Active full knee extension could be achieved at postoperative 10 months after the removal of wire loop.     

Stiffness After Revision Total Knee Arthroplasty

Stiffness after a revision total knee arthroplasty (TKA) is a disabling complication that has largely been overlooked in the literature. This study attempts to define the prevalence of stiffness after revision TKA and to determine the risk factors that may lead to its development. Thirty-two knees (4.0%) presented with stiffness that we defined as a range of motion less than 90°. Risk factors were found to be poor preoperative range of motion, stiffness as primary indication for revision, younger age, shorter interval between index primary and revision TKA, presence of well-fixed components at the time of revision, postoperative wound drainage, and lower Charlson index. Because of the challenges of treating stiffness, efforts should be invested in preventing this complication.     

Intraoperative Fracture During Aseptic Revision Total Knee Arthroplasty

Bone encountered during revision knee arthroplasty is compromised and predisposed to fracture. This study reports the rate, location, timing, treatment, and outcome of intraoperative fractures occurring during revision knee arthroplasty. Between 1997 and 2011, 2836 aseptic revisions were performed. Ninety-seven fractures were identified in 89 patients (3%). Fifty occurred in femora, 42 in tibiae, and 5 in patellae. Forty-six occurred during exposure, 21 during bony preparation, 17 during trialing, and 13 during final component placement. Treatment included fixation (n = 43), observation (n = 21), component build-up (n = 17), bone grafting (n = 6), and a combination (n = 3). Ninety-four percent of fractures united. Fifteen patients required a re-revision (17%), of which infection was the leading cause (n = 5).     

Anthropometry of the Proximal Tibia of Patients With Knee Arthritis in Shanghai

We measured the resected bony surface of the proximal tibia from reconstructed 3D models of the 179 arthritis knees using CT data. We found that the mediolateral (ML) dimension (69.6 ± 9.2 mm) and anteroposterior (AP) dimension (46.1 ± 6.1 mm) were less than those of Westerners. It was observed the medial anteroposterior (MAP) dimension (47.1 ± 7.2 mm) was much larger and closer to middle point of ML dimension than lateral anteroposterior (LAP) dimension (42.9 ± 6.3 mm). The aspect ratio (AR) (1.5 ± 0.07) was constant in Shanghai population. Only half of the prostheses we used in clinic mostly matched the resected bony surface of Shanghai population very well in ML, AP and AR dimension.     

Prior Knee Arthroscopy Is Associated With Increased Risk of Revision After Total Knee Arthroplasty

BackgroundKnee arthroscopy (KA) is frequently performed to provide improved joint function and pain relief. However, outcomes following total knee arthroplasty (TKA) after prior KA are not fully understood. The purpose of this study is to determine the relationship between prior KA within 2 years of TKA on revision rates after TKA.MethodsData were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2006 to 2017. Subjects were identified using Current Procedural Terminology and International Classification of Diseases procedure codes to identify primary TKA. Patients were stratified into 2 groups based upon a history of prior KA. Univariate and multivariate analyses were conducted to determine association between KA and outcomes at 2-year postoperative period.ResultsIn total, 138,019 patients were included in this study, with 3357 (2.4%) patients receiving a KA before TKA and 134,662 (97.6%) patients who did not. The most common reason for KA was osteoarthritis (40.0%), followed by medial tear of the meniscus (26.0%) and chondromalacia (21%.0). After adjustment, prior KA was associated with increased revision rate (odds ratio [OR], 1.392; P = .003), postoperative stiffness (OR, 1.251; P = .012), periprosthetic joint infection (OR, 1.326; P < .001), and aseptic loosening (OR, 1.401; P = .048).ConclusionPrior KA is significantly associated with increased 2-year TKA revision rate. The most common etiology for arthroscopy was osteoarthritis. The results of the study, showing that arthroscopy before TKA substantially increases the rates of revision, PJI, aseptic loosening, and stiffness, lend further credence to the idea that patients may be better served by nonsurgical management of their degenerative pathology until they become candidates for TKA. Subjecting this population to arthroscopy appears to offer limited benefit at the cost of poorer outcomes when they require arthroplasty in the future.Level of EvidenceLevel III therapeutic study.     

Extensor Mechanism Reconstruction with Achilles Tendon Allograft in TKA: Results of an Abbreviate Rehabilitation Protocol

Various treatment alternatives address extensor mechanism failure after total knee arthroplasty. We present the results of a protocol utilizing Achilles tendon allograft followed by an abbreviated immobilization program to treat extensor mechanism disruptions after TKA in 29 knees (27 patients). Failed reconstruction was defined as mechanical allograft failure requiring re-intervention, extension lag > 30°, recurrent falls, regression to a lower ambulatory status, and revision due to infection. With mean follow-up of 3.5 years, seventeen cases (58.6%) had satisfactory results, eleven cases (37.9%) were considered failures, and one case was lost to follow-up. Among failures, eight (27.5%) underwent reoperation with four (13.8%) due to late infections. Our observational data suggest that 1) a shortened immobilization protocol yields less favorable results than expected, and 2) continuous monitoring of patients who had allograft reconstruction for possible development of late infection is recommended.     

Long-Term Mortality Trends After Revision Total Knee Arthroplasty

Background

Long-term mortality following primary total knee arthroplasty (TKA) is lower than the general population. However, it is unknown whether this is true in the setting of revision TKA. We examined long-term mortality trends following revision TKA.

Revision Total Knee Arthroplasty in Young Patients: Higher Early Reoperation and Rerevision

BackgroundRevision total knee arthroplasty (rTKA) rates are increasing in younger patients. Few studies have assessed outcomes of initial aseptic rTKA performed for younger patients compared with traditional-aged patients.MethodsA detailed medical record review was performed to identify patient demographics, medical comorbidities, surgical rTKA indications, timing from index TKA to rTKA, subsequent reoperation rates, component rerevision rates, and salvage procedures for 147 young patients (158 knees) aged 55 years and younger and for a traditional older cohort of 276 patients (300 knees) between 60 and 75 years. Univariate analysis was performed to assess differences in these primary variables, and a log-rank test was used to estimate 5-year implant survival based on either reoperation or component revision and salvage procedures.ResultsYounger TKA patients were more likely to undergo initial aseptic rTKA within 2 years of their primary TKA (52.5% vs 29.0%, P < .001) and were more likely to undergo early reoperation (17.7% vs 9.7%, P = .02) or component rerevision (11.4% vs 6.0%, P < .05) after rTKA. Infection and extensor mechanism complications were more commonly noted in younger patients. Estimated 5-year survival was also lower for both reoperation (59.4% vs 65.7%, P = .02) and component rerevision or salvage (65.8% vs 80.1%, P = .02).ConclusionEarly reoperation and component re-rTKA were performed nearly twice as often in younger rTKA than traditional-aged TKA patients. Care should be given to reduce perioperative infection and extensor mechanism failures after rTKA in younger patients.     

Enhanced Biomechanical Performance of a Modern Polyester Surgical Mesh for Extensor Mechanism Reconstruction in Total Knee Arthroplasty

BackgroundExtensor mechanism (EM) disruption following total knee arthroplasty is a devastating postoperative complication. Reconstruction with a synthetic mesh is one treatment option, although the optimal mesh material remains unknown. This study sought to compare the mechanical properties of 2 mesh material types that can be used for EM reconstruction.MethodsMechanical properties of a polypropylene mesh (Marlex mesh) and Ligament Advanced Reinforcement System (LARS) mesh were compared using force-displacement data from a material testing machine simulating knee movement during normal human gait. Tension to failure/ultimate tensile load, stiffness coefficients, axial strain, and cyclic hysteresis testing were measured and calculated.ResultsCompared to polypropylene mesh, LARS mesh demonstrated a significantly higher mean ultimate tensile load (2223 N vs 1245 N, P = .002) and stiffness coefficient (255 N/mm vs 14 N/mm, P = .035) in tension to failure testing, and significantly more energy dissipation (hysteresis) in hysteresis testing (771 kJ vs 23 kJ; P ≤ .040). LARS mesh also demonstrated significantly less maximum displacement compared to the polypropylene mesh (9.2 mm vs 90.4 mm; P ≤ .001).ConclusionCompared to polypropylene mesh, LARS mesh showed superior performance related to force-displacement testing. The enhanced mechanical performance of LARS mesh may correlate clinically to fewer failures, increased longevity, and higher resistance to plastic deformation (extensor lag). Future research should evaluate survivorship and clinical outcomes of these meshes when used for EM reconstruction.     

Treatment of Extensor Tendon Disruption After Total Knee Arthroplasty: A Systematic Review

BackgroundPatellar or quadriceps tendon ruptures after total knee arthroplasty constitute a devastating complication with historically poor outcomes. With advances in soft tissue reconstruction and repair techniques, treatment has become more nuanced. Numerous graft options for reconstruction and suture techniques for repair have been described but there is no consensus regarding optimal treatment.MethodsA search of PubMed, MEDLINE, Embase, and Scopus was conducted. Articles meeting inclusion criteria were reviewed. Type of intervention performed, type of injury studied, outcome measures, and complications were recorded. Quantitative and qualitative analyses were performed.ResultsTwenty-eight articles met inclusion criteria. The complication rate after repair of patellar tendon (63.16%) was higher than the complication rate after repair of quadriceps tendon (25.37%). However, the complication rate for patellar and quadriceps tendon tears after autograft, allograft, or mesh reconstruction was similar (18.8% vs 19.2%, respectively). The most common complication after extensor mechanism repair or reconstruction was extension lag of 30° or greater (45.33%). This was followed by re-rupture and infection (25.33% and 22.67%, respectively). Early ruptures had a higher overall complication rate than late injuries.ConclusionExtensor mechanism disruption after total knee arthroplasty is a complication with high morbidity. Reconstruction of patellar tendon rupture has a much lower complication rate than repair. Our findings support the recommendation of patellar tendon reconstruction in both the early and late presentation stages. Quadriceps rupture can be treated with repair in early ruptures or with reconstruction in the late rupture or in the case of revision surgery.     

Weight Gain After Primary Total Knee Arthroplasty Is Associated With Accelerated Time to Revision for Aseptic Loosening

BackgroundObesity is a major health problem worldwide and is associated with complications after total knee arthroplasty (TKA). It remains unknown whether a change in body mass index (BMI) after primary TKA affects the reasons for revision TKA or the time to revision TKA.MethodsA total of 160 primary TKAs referred to an academic tertiary center for revision TKA were retrospectively stratified according to change in BMI from the time of their primary TKA to revision TKA. The association between change in BMI and time to revision was also analyzed according to indication for revision of TKA using Pearson's chi-square test.ResultsThe mean change in BMI from primary to revision TKA was 0.82 ± 3.5 kg/m². Maintaining a stable weight after primary TKA was protective against late revision TKA for any reason (P = .004). Patients who failed to reduce their BMI were revised for aseptic loosening earlier, at less than 5 years (P = .020), whereas those who reduced their BMI were revised later, at over 10 years (P = .004).ConclusionMaintaining weight after primary TKA is protective against later revision TKA for any reason but failure to reduce weight after primary TKA is a risk factor for early revision TKA for aseptic loosening and osteolysis. Orthopedic surgeons should recommend against weight gain after primary TKA to reduce the risk of an earlier revision TKA in the event that a revision TKA is indicated.     

Short-to-Midterm Outcomes of Revision Total Knee Arthroplasty Patients With a Total Stabilizer Knee System

Background

Revision total knee arthroplasty (TKA) can often be challenging. The use of a new revision system may aid in providing better stability, improved function, fit, and implant longevity. Therefore, we assessed: (1) survivorship, (2) clinical outcomes, (3) postoperative complications, and (4) radiographic outcomes of patients who underwent revision TKA using this system.

Reduced Infection Rate After Aseptic Revision Total Knee Arthroplasty With Extended Oral Antibiotic Protocol

BackgroundThe optimal postoperative antibiotic duration has not been determined for aseptic revision total knee arthroplasty (R-TKA) where the risk of periprosthetic joint infection (PJI) is 3%-7.5%. This study compared PJI rates in aseptic R-TKA performed with extended oral antibiotic prophylaxis (EOAP) to published rates.MethodsAseptic R-TKAs consecutively performed between 2013 and 2017 at a tertiary care referral center in the American Midwest were retrospectively reviewed. All patients were administered intravenous antibiotics while hospitalized and discharged on 7-day oral antibiotic prophylaxis. Infection rates and antibiotic-related complications were assessed.ResultsSixty-seven percent of the 176 analysis patients were female, with an average age of 64 years and body mass index of 35 kg/m². Instability and aseptic loosening comprised 86% of revision diagnoses. Overall, 87.5% of intraoperative cultures were negative, and the remainder were single positive cultures considered contaminants. PJI rates were 0% at 90 days, 1.8% (95% confidence interval 0.4%-5.3%) at 1 year, and 2.2% (95% confidence interval 0.6%-5.7%) at mean follow-up of approximately 3 years (range, 7-65 months).ConclusionEOAP after aseptic R-TKA resulted in a PJI rate equivalent to primary TKA, representing a 2- to-4-fold decrease compared with published aseptic R-TKA infection rates. Further study on the benefits and costs of EOAP after aseptic R-TKA is encouraged.     

The Fate and Relevance of the Patella in Two-Stage Revision Total Knee Arthroplasty for Periprosthetic Joint Infection

BackgroundIt remains unclear whether reimplantation of a patellar component during a two-stage revision for periprosthetic total knee arthroplasty infection (PJI) affects patient reported outcome measures (PROMs) or implant survivorship. The purpose of this study was to evaluate whether patellar resurfacing during reimplantation confers a functional benefit or increases implant survivorship after two-stage treatment for PJI.MethodsTwo-stage revisions for knee PJI performed by three surgeons at a single tertiary care center were reviewed retrospectively. All original patellar components and cement were removed during resection and the patella was resurfaced whenever feasible during reimplantation. PROMs, implant survivorship, and radiographic measurements (patellar tilt and displacement) were compared between knees reimplanted with a patellar component versus those without a patellar component.ResultsA total of 103 patients met the inclusion criteria. Forty-three patients (41.7%) underwent reimplantation with, and 60 patients (58.3%) without a patellar component. At a mean follow-up of 33.5 months, there were no significant differences in patient demographics or PROMs between groups (P ≥ .156). No significant differences were found in the estimated Kaplan-Meier all-cause, aseptic, or septic survivorship between groups (P ≥ .342) at a maximum of 75 months follow-up. There was no significant difference in the change (pre-resection to post-reimplant) of patellar tilt (P = .504) or displacement (P = .097) between the groups.ConclusionPatellar resurfacing during knee reimplantation does not appear to meaningfully impact postoperative PROMs or survivorship. Given the risk of potential extensor mechanism complications with patellar resurfacing, surgeons may choose to leave the patella without an implant during total knee reimplantation and expect similar clinical outcomes.Level of EvidenceLevel III.     

Gull-Wing Osteotomy for the Treatment of the Deficient Patella in Revision Total Knee Arthroplasty

Reconstruction of the deficient patella remains a challenge in revision total knee arthroplasty. Twelve consecutive patients who had a knee revision in which a nonresurfacable patella was treated with a gull-wing patellar osteotomy were followed using a computerized database. Radiographs revealed successful healing of the osteotomy in all patients with central tracking of the patella in the trochlear groove. There was a significant improvement in the range of motion and Knee Society scores. There were no patellar fractures or significant patellar malalignment in this series. This technique has shown promising results for the treatment of the nonresurfacable patella during revision total knee arthroplasty, and we conclude that it is a viable method of patellar salvage reserved for the most advanced cases of patellar bone stock compromise.