Abdel, Matthew P

ABSTRACTArthrofibrosis is a common complication following total knee arthroplasty caused by pathologic fibroblast activation and excessive collagen deposition around a synovial joint leading to debilitating loss of motion. Treatment options are limited because the pathologic mechanisms remain to be characterized. Dysregulation of the inflammatory cascade may lead to communication between myofibroblasts and immune cells triggering tissue metaplasia, and excessive collagen deposition described clinically as arthrofibrosis. We explored the novel use of celecoxib (selective cyclooxygenase‐2 [COX‐2] inhibitor) to disrupt the downstream effects of the post‐traumatic inflammatory cascade and inhibit scar tissue formation in a validated rabbit model of arthrofibrosis combined with new parameters for quantifying the stiffness of the posterior capsule. Biomechanical and molecular analyses, of contracted rabbit knee posterior capsule tissue after COX‐2 inhibition revealed increased maximal passive extension and down‐regulation of collagen messenger RNA compared with controls. Histopathologic examination suggested a trend of decreased quantities of dense fibrous connective tissue with COX‐2 inhibition. These data may suggest that inhibiting the inflammatory cascade could potentially reduce pathologic myofibroblast activation, thereby reducing scar tissue formation and increasing the range of motion in arthrofibrotic joints. Implementing a multi‐modal pharmacologic approach may simultaneously target numerous cellular components contributing to the complex process of arthrofibrogenesis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2609–2620, 2019

Background: Stiffness is a common reason for suboptimal clinical outcomes after primary total knee arthroplasty (pTKA). There is a lack of consensus regarding its definition, which is often conflated with its histopathologic subcategory—i.e., arthrofibrosis. There is value in refining the definition of acquired idiopathic stiffness in an effort to select for patients with arthrofibrosis. We conducted a systematic review and meta-analysis to establish a consensus definition of acquired idiopathic stiffness, determine its prevalence after pTKA, and identify potential risk factors for its development. Methods: MEDLINE, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Scopus databases were searched from 2002 to 2017. Studies that included patients with stiffness after pTKA were screened with strict inclusion and exclusion criteria to isolate the subset of patients with acquired idiopathic stiffness unrelated to known extrinsic or surgical causes. Three authors independently assessed study eligibility and risk of bias and collected data. Outcomes of interest were then analyzed according to age, sex, and body mass index (BMI). Results: In the 35 included studies (48,873 pTKAs), the mean patient age was 66 years. In 63% of the studies, stiffness was defined as a range of motion of <90° or a flexion contracture of >5° at 6 to 12 weeks postoperatively. The prevalence of acquired idiopathic stiffness after pTKA was 4%, and this did not differ according to age (4%, I 2 = 95%, among patients <65 years old and 5%, I 2 = 96%, among those ≥65 years old; p = 0.238). The prevalence of acquired idiopathic stiffness was significantly lower in males (1%, I 2 = 85%) than females (3%, I 2 = 95%) (p < 0.0001) as well as in patients with a BMI of <30 kg/m 2 (2%, I 2 = 94%) compared with those with a BMI of ≥30 kg/m 2 (5%, I 2 = 97%) (p = 0.027). Conclusions: Contemporary literature supports the following definition for acquired idiopathic stiffness: a range of motion of <90° persisting for >12 weeks after pTKA in patients in the absence of complicating factors including preexisting stiffness. The mean prevalence of acquired idiopathic stiffness after pTKA was 4%; females and obese patients were at increased risk. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Povidone-iodine (PI) irrigation is often used prior to wound closure in total joint arthroplasty, but there are limited reports evaluating its efficacy in decreasing joint infections. The goal of this study was to compare the rate of any reoperation for infection (both superficial and deep) in primary total hip arthroplasty (THA) and primary total knee arthroplasty (TKA) among patients who did and did not receive PI irrigation prior to wound closure. Methods: Using our institution’s total joint registry, we identified 5,534 primary THA and 6,204 primary TKA procedures performed from 2013 to 2017. Cases were grouped on the basis of whether or not the wound was irrigated with 1 L of 0.25% PI prior to closure. PI irrigation was used in 1,322 (24%) of the THA cases and in 2,410 (39%) of the TKA cases. The rates of reoperation for infection at 3 months and 1 year were compared between the 2 groups. The same comparisons were then performed using propensity scores to account for differences in baseline characteristics. Results: The rate of reoperation for infection as assessed at 3 months following THA was similar between those who received dilute PI irrigation (0.9%) and who did not (0.7%) (p = 0.7). At 1 year, the rate of reoperation for infection was similar between those who received dilute PI irrigation (0.7%) and those who did not (0.9%) (p = 0.6). After using the propensity score, there was no difference between the groups in the risk of septic reoperations. For TKA, the rate of reoperation as assessed at 3 months was similar between those who received dilute PI irrigation (0.8%) and those who did not (0.3%) (p = 0.06). At 1 year, there was a greater rate of reoperations for infection among those who received dilute PI irrigation (1.2%) compared with those who did not (0.6%) (p = 0.03). However, there was no difference in the risk of septic reoperations between the groups after using the propensity score. Conclusions: Despite enthusiasm for and progressive adoption of the use of dilute PI irrigation at our institution, there was not a significant reduction in the risk of reoperation for infection as assessed at 3 months and 1 year following primary THA and TKA. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Postoperative infection remains a major challenge in revision total hip arthroplasty (THA) and revision total knee arthroplasty (TKA). Wound irrigation with dilute povidone-iodine (PI) solution has emerged as a simple, inexpensive, and potentially successful means of reducing postoperative infections. The aim of this study was to assess its effectiveness in reducing infection following revision THA and TKA in, to our knowledge, the largest revision cohort to date. Methods: Using our institution’s total joint registry, we identified 1,402 revision THAs and 1,482 revision TKAs performed during the study period (2013, when the PI irrigation protocol was first implemented, to 2017). The PI lavage protocol was employed in 27% of the revision THA cases and 34% of the revision TKA cases; in the remaining cases, the protocol was not used. Demographics, comorbid conditions, underlying surgical diagnoses, and whether the revision was for a septic or an aseptic etiology were compared between the groups (use or no use of PI irrigation). Any reoperation due to infection, as assessed at 3 and 12 months following revision arthroplasty, was compared between the groups and propensity scores were calculated to account for differences in baseline characteristics between the groups. Results: After adjusting for baseline differences between the groups using the propensity-score weighted models, we found no significant difference in the rate of reoperation for infection at 3 months (p = 0.58 for revision THA, and p = 0.06 for revision TKA) and at 12 months (p = 0.78 for revision THA, and p = 0.06 for revision TKA). Nonetheless, the hazard ratios from the propensity-score model trended higher for patients who received PI lavage: 1.6 and 1.3 for revision THA at 3 and 12 months, respectively, and 2.9 at both 3 and 12 months for revision TKA. Conclusions: PI wound lavage demonstrated no benefit in reducing any reoperation for infection following revision THA and TKA. Moreover, the trend toward higher rates for reoperation for infection among patients who received PI irrigation merit further consideration. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Marlex mesh reconstruction of the extensor mechanism via a stepwise surgical approach is a viable option to treat disruption of the extensor mechanism after total knee arthroplasty (TKA). Description: Extensor mechanism reconstruction with mesh involves a stepwise surgical approach with a particular monofilament polypropylene mesh (Marlex; C.R. Bard). Prior to incision, the 10 × 14-in (25 × 36-cm) sheet of Marlex mesh is rolled onto itself 8 to 10 times and sewn together. If the tibia is not being revised, a burr is utilized to create a trough in the tibia. Five centimeters of the tapered portion of the mesh are predipped in bone cement. The remaining cement is inserted into the trough. The tapered portion of the mesh is inserted into the tibial trough, ensuring that the mesh is fully seated. After the cement has cured, a lag screw is placed across the mesh and cement and into host bone. If the tibia is being revised at the time of the Marlex mesh reconstruction, the 5 cm of predipped mesh is placed anteriorly in the medullary canal in line with the tibial crest. The remaining procedure is similar regardless of whether the components are revised. At the level of the joint, it is essential to ensure that the mesh is covered with host tissue. Next, the proximal reconstruction, which involves mobilizing the vastus lateralis and vastus medialis obliquus (VMO) distally by releasing all ventral and dorsal soft-tissue adhesions off the muscle bellies, is completed. Finally, the mesh is unitized to the vastus lateralis. With the limb maintained in full extension, the mesh is pulled directly proximally while another assistant pulls the vastus lateralis distally and medially. The vastus lateralis is deep, and the mesh is directly on top of it. Multiple nonabsorbable sutures are placed through the mesh and vastus lateralis. The VMO is then pulled distally and laterally over the mesh (which is now unitized to the vastus lateralis) by an assistant. Multiple nonabsorbable sutures (usually 8) are placed through the VMO, through the mesh, and through the vastus lateralis, unitizing the entire construct. Alternatives: Nonoperative treatments include a drop-lock hinge brace or knee immobilizer. Operative treatments include whole extensor mechanism allograft reconstruction or Achilles tendon allograft reconstruction. Rationale: The procedure avoids the limitations of allograft with regard to availability, cost, and risk of disease transmission. The technique is reproducible and cost-effective, and it has excellent functional and survivorship outcomes.

Background: Some prior reports of total knee arthroplasty after high tibial osteotomy have shown high rates of aseptic loosening. As such, the goal of this study was to analyze the outcomes of contemporary total knee arthroplasty after high tibial osteotomy, with particular emphasis on survivorship free from aseptic loosening, any revision, and any reoperation; complications; radiographic results; and clinical outcomes. Methods: We retrospectively reviewed 207 patients who underwent 231 total knee arthroplasties using cemented prostheses after high tibial osteotomy from 2000 to 2012 through our total joint registry: 87% were after a closing-wedge osteotomy and 13% were after an opening-wedge osteotomy. The mean follow-up from total knee arthroplasty was 8 years. At the time of the total knee arthroplasty, the mean age was 64 years and the mean body mass index was 31 kg/m 2 . The majority of total knee arthroplasties had a posterior-stabilized design (93%), and 4% had a varus-valgus constraint design. Tibial stems were utilized in 8% of cases. Bivariate and multivariate Cox regression analyses were utilized to analyze risk factors for poorer survival. Results: At 10 years, survivorship free from aseptic loosening was 97%, survivorship free from any revision was 90%, and survivorship free from any reoperation was 85%. Fifteen patients (15 total knee arthroplasties [6%]) underwent aseptic revision, most commonly for instability (3%), aseptic loosening (2%), and periprosthetic fracture (1%). On bivariate analysis, patient age of <60 years was a significant risk factor for poorer revision-free survival (hazard ratio, 2.9; p = 0.02); on multivariate analysis, younger age was the only significant risk factor for revision (p = 0.04). There were 14 complications (6%), the most common being a manipulation under anesthesia in 9 cases (4%). No unrevised total knee arthroplasties had definitive radiographic evidence of loosening. Knee Society scores improved from a mean preoperative score of 59 points to a mean postoperative score of 93 points (p < 0.001). Conclusions: Contemporary total knee arthroplasty with a cemented prosthesis after high tibial osteotomy demonstrated excellent long-term durability, with 10-year survivorship free from aseptic loosening of 97%. There was reliable improvement in clinical outcomes, but perfect knee balance was sometimes challenging, as reflected by a 4% prevalence of manipulation under anesthesia and a 3% prevalence of revision for instability. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Cementation of a constrained liner is a viable option for treating instability after total hip arthroplasty (THA) when the acetabular component is well fixed and well aligned. However, concerns regarding long-term mechanical failure and recurrent instability remain. The aim of this study was to evaluate the long-term survivorship, complications, and clinical and radiographic outcomes of constrained polyethylene liners cemented into well-fixed acetabular components at the time of revision THA. Methods: We identified 125 cases in which a constrained liner of 1 design was cemented into a retained, osseointegrated acetabular component during revision THA between 1998 and 2006. The mean patient age at revision was 70 years. Mean follow-up was 7 years. Survivorship data, risk of instability, and clinical and radiographic outcomes were analyzed. Results: Survivorship free from revision for instability was 86% at 5 years and 81% at 10 years. Survivorship free from aseptic acetabular component revision was 78% at 5 years and 65% at 10 years, with the most common failure mechanism being dissociation of the constrained liner from the acetabular component. Survivorship free from revision for any reason was 76% at 5 years and 60% at 10 years. The most common complications were instability and periprosthetic joint infection, with cumulative incidences at 7 years of 18% and 11%, respectively. Harris hip scores did not significantly improve. Cup position did not affect implant survivorship or risk of dislocation. Conclusions: Cementing a constrained liner into a retained acetabular shell at the time of revision THA has durable long-term results, with 8 in 10 patients free from instability at 10 years. Aseptic acetabular survivorship was worse (65%) at 10 years, primarily due to dissociation of the constrained liner from the acetabular component. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Polyethylene (PE) liner and femoral head exchange is commonly used to treat periprosthetic osteolysis associated with PE wear after total hip arthroplasty (THA). The purpose of our study was to determine long-term implant survivorship, risk factors for mechanical failure, clinical outcomes, and complications following PE liner and head exchange. Methods: We identified 116 hips in 110 patients treated with PE liner and head exchange from 1993 to 2004. There were 64 women (58%) in the series, the mean age at revision surgery was 58 years, and the mean follow-up was 11 years (range, 2 to 23 years). Radiographic review determined the location and size of osteolytic defects before the revision surgery. Implant survivorship was determined using Kaplan-Meier survival analysis. Cox regression analysis was used to determine factors that were predictive of failure. Results: Implant survivorship free of repeat revision for any cause was 91% (95% confidence interval [CI] = 86% to 96%) at 5 years, 81% (95% CI = 74% to 90%) at 10 years, and 69% (95% CI = 55% to 84%) at 15 years. Reasons for repeat revision included aseptic acetabular loosening in 5 hips (4%) and subsequent wear of conventional PE with osteolysis in 5 hips (4%). No patient who underwent revision with highly cross-linked PE subsequently had a repeat revision due to wear. The absolute risk of acetabular component loosening was 23% for patients with osteolysis in 3 zones, 40% for those with osteolysis involving more than half the cup circumference, and 21% for those with osteolytic defects of >600 mm 2 . The mean Harris hip score improved from 77 before the PE liner and head exchange to 87 after it (p < 0.001). The most common complication was dislocation, which occurred in 19 hips (16%). Conclusions: PE liner and head exchange provides acceptable long-term implant survivorship with good clinical outcomes. Complications are not uncommon, and steps should be taken to mitigate hip instability. Acetabular revision may be considered when in situ components have a poor track record or are malpositioned, or when preoperative radiographs demonstrate large osteolytic defects threatening cup fixation. Use of highly cross-linked PE at revision was protective against subsequent PE wear and osteolysis, although this did not reach significance. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Two-stage exchange is the most common form of treatment of chronic infection following total hip arthroplasty (THA). We examined the prevalence of, and risk factors associated with, hip instability following 2-stage exchange as well as the fate of reimplanted hip prostheses that dislocated. Methods: Data on 515 2-stage exchange THAs performed between 2000 and 2014 at a single institution were retrospectively reviewed. Risk factors for instability as well as postoperative reoperations and revisions were analyzed. The impact of dislocation on these outcomes was evaluated as well. The mean age at the time of reimplantation was 65 years, and the mean duration of follow-up was 5 years (range, 2 to 15 years). Results: Dislocation occurred in 52 hips following reimplantation (cumulative probability = 8.9% at 1 year). There was a higher risk of instability in women (hazard ratio [HR] = 1.8, p = 0.038) and in those who had a history of dislocation prior to the 2-stage revision (HR = 5.1, p < 0.001). Younger age, body mass index, number of previous operations, spacer type, surgical approach, use of a constrained liner, femoral head diameter, and persistent or recurrent infection were not found to be significant risk factors. Patients with an absent or ununited greater trochanter or abductor deficiency also had a higher rate of dislocation (HR = 30, p < 0.001), as did patients who underwent reimplantation with a megaprosthesis (HR = 6.0, p < 0.001). The risk of additional reoperations (HR = 121, p < 0.001) and revision surgery (HR = 13, p < 0.001) was significantly higher in patients who experienced a dislocation after the 2-stage exchange. Conclusions: Dislocation after 2-stage exchange THA continues to be a major concern, with the 1-year cumulative probability found to be 9% in the present study. Female sex, a history of dislocation, an absent or ununited greater trochanter or abductor deficiency, and reimplantation with a megaprosthesis were identified as risk factors for dislocation. There is a remarkable 121-fold increase in the rate of reoperations and a 13-fold increase in the rate of revisions in hips that dislocated after 2-stage exchange THA. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: For patients undergoing 2-stage exchange for the treatment of periprosthetic joint infection (PJI) following total knee arthroplasty, the long-term risk of reinfection and mechanical failure and long-term clinical outcomes are not well known. The purpose of our study was to determine the long-term clinical results of 2-stage exchange for PJI following total knee arthroplasty. Methods: We identified 245 knees that had undergone total knee arthroplasty and were subsequently treated with 2-stage exchange due to infection during the period of 1991 to 2006; the cohort had no prior treatment for PJI. Major, or 4 of 6 minor, Musculoskeletal Infection Society (MSIS) diagnostic criteria were fulfilled by 179 (73%) of the knees. The cumulative incidence of reinfection and of aseptic revision, accounting for the competing risk of death, were calculated. Risk factors for reinfection were evaluated using Cox proportional hazards regression. Knee Society Score (KSS) values were calculated. The mean age at spacer insertion was 68 years; 50% of the patients were female. The mean follow-up was 14 years (range, 2 to 25 years) following reimplantation. Results: The cumulative incidence of reinfection was 4% at 1 year, 14% at 5 years, 16% at 10 years, and 17% at 15 years. Factors that were predictive of reinfection included a body mass index of ≥30 kg/m 2 (hazard ratio [HR], 3.1; p < 0.01), previous revision surgery (HR, 2.8; p < 0.01), and a McPherson host grade of C (HR, 2.5; p = 0.04). The cumulative incidence of aseptic revision for loosening was 2% at 5 years, 5% at 10 years, and 7% at 15 years. Femoral (HR, 5.0; p = 0.04) and tibial (HR, 6.7; p < 0.01) bone-grafting at reimplantation were predictive of aseptic failure. The most common complications were wound-healing issues, requiring reoperation in 12 (5%) of the knees. The rate of death at 2 years following reimplantation was 11%. The mean KSS improved from 45 at PJI diagnosis to 76 at 10 years following reimplantation (p < 0.01). Conclusions: Long-term reinfection rates following 2-stage exchange for PJI after total knee arthroplasty were similar to those of shorter-term reports and were maintained out to 15 years. Mechanical failure rates were low if bone loss was addressed at the time of reimplantation. Improvements in clinical outcomes were maintained at long-term follow-up. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.