Abdel, Matthew P.

AimsVarus-valgus constrained (VVC) implants are often used during revision total knee arthroplasty (TKA) to gain coronal plane stability. However, the increased mechanical torque applied to the bone-cement interface theoretically increases the risk of aseptic loosening. We assessed mid-term survivorship, complications, and clinical outcomes of a fixed-bearing VVC device in revision TKAs.MethodsA total of 416 consecutive revision TKAs (398 patients) were performed at our institution using a single fixed-bearing VVC TKA from 2007 to 2015. Mean age was 64 years (33 to 88) with 50% male (199). Index revision TKA diagnoses were: instability (n = 122, 29%), aseptic loosening (n = 105, 25%), and prosthetic joint infection (PJI) (n = 97, 23%). All devices were cemented on the epiphyseal surfaces. Femoral stems were used in 97% (n = 402) of cases, tibial stems in 95% (n = 394) of cases; all were cemented. In total, 93% (n = 389) of cases required a stemmed femoral and tibial component. Femoral cones were used in 29%, and tibial cones in 40%. Survivorship was assessed via competing risk analysis; clinical outcomes were determined using Knee Society Scores (KSSs) and range of movement (ROM). Mean follow-up was four years (2 to 10).ResultsThe five-year cumulative incidence of subsequent revision for aseptic loosening and instability were 2% (95% confidence interval (CI) 0.2 to 3, number at risk = 154) and 4% (95% CI 2 to 6, number at risk = 153), respectively. The five-year cumulative incidence of any subsequent revision was 14% (95% CI 10 to 18, number at risk = 150). Reasons for subsequent revision included PJI (n = 23, of whom 12 had previous PJI), instability (n = 13), and aseptic loosening (n = 11). The use of this implant without stems was found to be a significant risk factor for subsequent revision (hazard ratio (HR) 7.58 (95% CI 3.98 to 16.03); p = 0.007). KSS improved from 46 preoperatively to 81 at latest follow-up (p < 0.001). ROM improved from 96° prerevision to 108° at latest follow-up (p = 0.016).ConclusionThe cumulative incidence of subsequent revision for aseptic loosening and instability was very low at five years with this fixed-bearing VVC implant in revision TKAs. Routine use of cemented and stemmed components with targeted use of metaphyseal cones likely contributed to this low rate of aseptic loosening. Cite this article: Bone Joint J 2020;102-B(4):458–462.

AbstractThe dense formation of abnormal scar tissue after total knee arthroplasty results in arthrofibrosis, an unfortunate sequela of inflammation. The purpose of this study was to use a validated rabbit model to assess the effects on surgically‐induced knee joint contractures of two combined pharmacological interventions: celecoxib (CXB) loaded on an implanted collagen membrane, and subcutaneously (SQ) injected ketotifen. Thirty rabbits were randomly divided into five groups. The first group received no intervention after the index surgery. The remaining four groups underwent intra‐articular implantation of collagen membranes loaded with or without CXB at the time of the index surgery; two of which were also treated with SQ ketotifen. Biomechanical joint contracture data were collected at 8, 10, 16, and 24 weeks. At the time of necropsy (24 weeks), posterior capsule tissue was collected for messenger RNA and histopathologic analyses. At 24 weeks, there was a statistically significant increase in passive extension among rabbits in all groups treated with CXB and/or ketotifen compared to those in the contracture control group. There was a statistically significant decrease in COL3A1, COL6A1, and ACTA2 gene expression in the treatment groups compared to the contracture control group (P < .001). Histopathologic data also demonstrated a trend towards decreased fibrous tissue density in the CXB membrane group compared to the vehicle membrane group. The present data suggest that intra‐articular placement of a treated collagen membrane blunts the severity of contracture development in a rabbit model of arthrofibrosis, and that ketotifen and CXB may independently contribute to the prevention of arthrofibrosis. Statement of clinical significance: Current literature has demonstrated that arthrofibrosis may affect up to 5% of primary total knee arthroplasty patients. For that reason, novel pharmacologic prophylaxis and treatment modalities are critical to mitigating reoperations and revisions while improving the quality of life for patients with this debilitating condition.

Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved.Cite this article: Bone Joint J 2020;102-B(3):276–279.

Background: The efficacy and safety of tranexamic acid (TXA) in primary total knee arthroplasty (TKA) have been well established. However, there have been limited data for revision TKAs. The primary aim was to assess the impact of intravenous TXA on transfusion rates and symptomatic venous thromboembolic events (VTEs) in a large revision TKA cohort with or without intravenous TXA utilization. Methods: A retrospective review of revision TKAs performed from 2005 to 2014 was performed, identifying 2,951 procedures (2,219 patients), in which TXA was utilized in 1,144 procedures (39%). The mean age was 65 years with 52% female patients in the TXA revision group and 67 years with 52% female patients in the non-TXA revision group. Transfusion rates and symptomatic VTEs were the primary outcomes assessed. Comparisons were performed between cohorts, utilizing a unique propensity model to mitigate bias, on the basis of TXA use and subsequently for aseptic or septic revision etiology. Results: Significant reductions in transfusion rates with use of TXA were identified in revision TKAs overall (13% compared with 39%; p < 0.001 [adjusted relative risk, 1.7]), including revisions for both aseptic etiology (6% with TXA compared with 28% without TXA; p < 0.001) and septic etiology (31% with TXA compared with 54% without TXA; p < 0.001). The risk of a postoperative symptomatic VTE was not significantly different (adjusted p = 0.63) with use of TXA at 11 events (1.0%) compared with 24 events (1.3%) in the non-TXA group). Conclusions: Intravenous TXA significantly reduced transfusion rates in revision TKAs by approximately twofold, including cohorts revised for aseptic and septic etiologies. There was a very low rate of VTEs (1.2%) with no significant difference in the number of VTEs between groups after adjusting risk utilizing propensity modeling. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

There is continued debate as to whether cemented or cementless implants should be utilized in particular cases based upon chronological age. This debate has been rekindled in the UK and other countries by directives mandating certain forms of acetabular and femoral component fixation based exclusively on the chronological age of the patient. This editorial focuses on the literature-based arguments to support the use of cementless total hip arthroplasty (THA), while addressing potential concerns surrounding safety and cost-effectiveness.Cite this article: Bone Joint Res. 2019;8(12):604–607.

Metagenomic shotgun sequencing for the identification of pathogens is being increasingly utilized as a diagnostic method. Interpretation of large and complicated data sets is a significant challenge, for which multiple commercial tools have been developed. Three commercial metagenomic shotgun sequencing tools, CosmosID, One Codex, and IDbyDNA, were compared to determine whether they result in similar interpretations of the same sequencing data.

Background: Debate surrounds the issue of whether peripheral nerve blockade or periarticular infiltration (PAI) should be employed within a contemporary, comprehensive multimodal analgesia pathway for total hip arthroplasty. We hypothesized that patients treated with a continuous posterior lumbar plexus block (PNB) would report less pain and consume less opioid medication than those treated with PAI. Methods: This investigator-initiated, independently funded, 3-arm randomized clinical trial (RCT) performed at a single high-volume institution compared postoperative analgesia interventions for elective, unilateral primary total hip arthroplasty: (1) PNB; (2) PAI with ropivacaine, ketorolac, and epinephrine (PAI-R); and (3) PAI with liposomal bupivacaine, ketorolac, and epinephrine (PAI-L) using computerized randomization. The primary outcome was maximum pain during the morning (06:00 to 12:00) of the first postoperative day (POD) on an ascending numeric rating scale (NRS) from 0 to 10. Pairwise treatment comparisons were performed using the rank-sum test, with a p value of <0.017 indicating significance (Bonferroni adjusted). A sample size of 150 provided 80% power to detect a difference of 2.0 NRS units. Results: We included 159 patients (51, 54, and 54 patients in the PNB, PAI-R, and PAI-L groups, respectively). No significant differences were found with respect to the primary end point on the morning of the first POD (median, 3.0, 4.0, and 3.0, respectively; p > 0.033 for all). Opioid consumption was low and did not differ across groups at any intervals. Median maximum pain on POD 1 was 5.0, 5.5, and 4.0, respectively, and was lower for the PAI-L group than for the PAI-R group (p = 0.006). On POD 2, maximum pain (median, 3.5, 5.0, and 3.5, respectively) was lower for the PNB group (p = 0.014) and PAI-L group (p = 0.016) compared with the PAI-R group. The PAI-L group was not significantly different from the PNB group with respect to any outcomes: postoperative opioid use including rescue intravenous opioid medication, length of stay, and hospital adverse events, and 3-month follow-up data including any complication. Conclusions: In this RCT, we found a modest improvement with respect to analgesia in patients receiving PNB compared with those receiving PAI-R, but not compared with those who had PAI-L. Secondary analyses suggested that PNB or PAI-L provides superior postoperative analgesia compared with PAI-R. For primary total hip arthroplasty, a multimodal analgesic regimen including PNB or PAI-L provides opioid-limiting analgesia. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

AimsKnee osteonecrosis in advanced stages may lead to joint degeneration. Total knee arthroplasty (TKA) for osteonecrosis has traditionally been associated with suboptimal results. We analyzed outcomes of contemporary TKAs for osteonecrosis, with particular emphasis on: survivorship free from aseptic loosening, any revision, and any reoperation plus the clinical outcomes, complications, and radiological results.Patients and MethodsIn total, 156 patients undergoing 167 primary TKAs performed for osteonecrosis between 2004 and 2014 at a single institution were reviewed. The mean age at index TKA was 61 years (14 to 93) and the mean body mass index (BMI) was 30 kg/m2(18 to 51) The mean follow-up was six years (2 to 12). A total of 110 TKAs (66%) were performed for primary osteonecrosis and 57 TKAs (34%) for secondary osteonecrosis. Overall, 15 TKAs (9%) had tibial stems, while 12 TKAs (7%) had femoral stems. Posterior-stabilized designs were used in 147 TKAs (88%) of TKAs. Bivariate Cox regression analysis was conducted to identify risk factors for revision and reoperation.ResultsSurvivorship free from aseptic loosening, any revision, and any reoperation at ten years was 97% (95% confidence interval (CI) 93 to 100), 93% (95% CI 85 to 100), and 82% (95% CI 69 to 93), respectively. No factors, including age, sex, BMI, primary versus secondary osteonecrosis, stem utilization, and constraint, were identified as risk factors for reoperation. Four TKAs (2%) underwent revision, most commonly for tibial aseptic loosening (n = 2). Excluding revisions and reoperations, there was a total of 11 complications (7%), with the most common being a manipulation under anaesthesia (six TKAs, 4%). Mean Knee Society Scores (Knee component) significantly improved from 57 (32 to 87) preoperatively to 91 (49 to 100) postoperatively (p < 0.001). No unrevised TKAs had complete radiolucent lines or radiological evidence of loosening.ConclusionContemporary cemented TKAs with selective stem utilization for osteonecrosis resulted in durable survivorship, a low complication rate, and reliable improvement in clinical outcomes. Cite this article: Bone Joint J 2019;101-B:1356–1361.

Background: Distal femoral replacement (DFR) is a salvage option for complex primary and revision total knee arthroplasty (TKA). Although excellent immediate fixation and weight-bearing are achieved, there is a paucity of data on long-term outcomes of TKA with DFR. The purpose of the present study was to determine implant survivorship, clinical outcomes, and radiographic results of TKAs with contemporary DFR components in a large series. Methods: We identified 144 consecutive TKAs performed with DFR for non-oncologic indications from 2000 to 2015 at a single academic institution. Indications for the index DFR included 66 (46%) for native (n = 11) or periprosthetic (n = 55) femoral fracture, 40 (28%) for staged treatment of periprosthetic joint infection, 28 (19%) for aseptic TKA loosening, and 10 (7%) for other indications. Porous metal cones were used to augment femoral fixation in 28 patients (19%) and tibial fixation in 38 patients (26%). Outcomes included cumulative incidence of revision and reoperation (utilizing a competing risk model), Knee Society scores, and radiographic results. The mean age at the time of index DFR was 72 years, and 65% of patients were female. The mean follow-up was 5 years (range, 2 to 13 years) for the 111 patients who did not undergo revision, had not died, and were not lost to follow-up. Results: The 10-year cumulative incidences of revision for aseptic loosening, all-cause revision, and any reoperation were 17.0%, 27.5%, and 46.3%, respectively. There was an increased risk of reoperation in patients who underwent index DFR for aseptic TKA loosening (hazard ratio [HR], 2.30; p = 0.026) or periprosthetic joint infection (HR, 2.18; p = 0.022) compared with periprosthetic or native femoral fractures. However, there was no difference in risk of revision for aseptic loosening or all-cause revision based on the original operative indication. The mean Knee Society score increased from 45 preoperatively to 71 at the time of the latest follow-up (p < 0.001). Radiographic loosening was observed in 8 unrevised DFRs (7%). There were 7 above-the-knee amputations performed at the time of the final follow-up, all for intractable periprosthetic joint infection. Conclusions: TKAs with contemporary DFR had high 10-year cumulative incidences of both revision and reoperation, underscoring the salvage nature of this procedure as a final reconstructive option. Most patients experienced substantial clinical improvements with this end-stage revision procedure. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: There is no consensus on managing severe patellar bone loss after total knee arthroplasty. We previously described an initial series involving a novel technique of patellar bone-grafting with a short follow-up. The purpose of this study was to determine long-term survivorship and the radiographic and clinical results of patellar bone-grafting during revision total knee arthroplasty in a larger series with an extended follow-up. Methods: We identified 90 patients from a single institution who underwent 93 patellar bone-grafting procedures for severe patellar bone loss from 1997 to 2014. The mean age of the patients was 70 years, and 46% of patients were female. Forty-five knees (48%) underwent first-time revisions, and 19 knees (20%) had undergone a failed attempt at patellar resurfacings. Intraoperative patellar caliper thickness increased from a mean of 7 to 25 mm after patellar bone-grafting (p < 0.01). Radiographic review determined changes in patellar height, tracking, and remodeling. Knee Society scores (KSSs) were calculated. The mean follow-up was 8 years (range, 2 to 18 years). Kaplan-Meier methods determined survivorship free of any revision and any reoperation. Cox proportional hazards analysis determined predictive factors for failure. Results: Survivorship free of patellar revision was 96% at 10 years. Survivorship free of any revision was 84% at 10 years. Survivorship free of any reoperation was 78% at 10 years. Increasing patient age was the only protective factor against further patellar revision (hazard ratio, 0.95; p < 0.01). When comparing initial radiographs with final radiographs, patellar height decreased from 22 to 19 mm (p < 0.01), 80% compared with 59% of patellae articulated centrally in the trochlea (p = 0.01), and 32% compared with 77% had remodeling over the lateral femoral condyle (p < 0.01). Anterior knee pain decreased from 51% to 27% postoperatively (p = 0.01). The mean knee flexion improved from 101° to 108° (p = 0.03). The mean KSS improved from 50 to 85 points (p < 0.01). Conclusions: Reliable long-term clinical results can be expected with patellar bone-grafting for severe patellar bone loss during revision total knee arthroplasty. Pain, range of motion, and other reported outcomes improve despite radiographic changes to patellar height, tracking, and remodeling. This technique is a durable and reliable option when standard patellar resurfacing is not possible. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.