Use of National Joint Registries to Evaluate a New Knee Arthroplasty Design.

BACKGROUND: The introduction of new technology in joint replacement surgery requires close monitoring to identify early successes and failures. This monitoring can be effectively performed through the analysis of registry data and radiostereometric analysis studies. This study examined the revision rates of a contemporary knee system for total knee arthroplasty (TKA) using National Joint Replacement Registries. METHODS: A review of the literature was performed to identify comparative studies and registry databases reporting the revision rates of a specific contemporary knee design between 2013 and 2018. The total number of TKA cases performed using this implant was recorded. The latest follow-up or duration of monitoring through a registry database was used to report implant survivorship. RESULTS: There were 4 registry databases and 1 comparative study reporting the revision rates of the contemporary knee system. A total of 41,483 cases were identified with a follow-up range of 1.5-5.0 years. The all-cause revision rate ranged from 0.7% to 2.5% at latest follow-up. This was comparable to all-cause revision rates of other knee systems reported in the registries, ranging from 0.8% to 5.6% over similar follow-up periods. CONCLUSIONS: Evaluation of data from multiple national joint registries demonstrated the revision rate for this contemporary knee system to be comparable to other TKA systems at latest follow-up. None of the registries have identified any concerning rates of revision compared to other devices at this length of follow-up. National Joint Registries are an important resource in evaluating the short-term, mid-term, and long-term results of new implant designs introduced to the market.

Infection After Unicompartmental Knee Arthroplasty: A High Risk of Subsequent Complications.

BACKGROUND: Unicompartmental knee arthroplasty restores function and improves pain in appropriately selected patients. Scant evidence exists regarding the treatment of periprosthetic joint infection (PJI) after unicompartmental knee arthroplasty (UKA). QUESTIONS/PURPOSES: (1) What was the overall survivorship free from reinfection? (2) What is the survivorship free of all-cause revision? (3) What are the Knee Society scores (KSS) and complications after surgical treatment of UKA PJI? METHODS: This retrospective study with data drawn from a longitudinally maintained institutional registry identified 15 UKA PJIs between 1992 and 2014. The median age at PJI diagnosis was 58 years (range, 41-82 years), nine of 15 were men, and the median body mass index was 29 kg/m (range, 23-36 kg/m). Ten patients (10 of 15) satisfied major Musculoskeletal Infection Society diagnostic criteria. There were five patients (five of 15) with early postoperative infections, five (five of 15) with acute hematogenous infections, and five (five of 15) with chronic PJIs. Two-stage exchange was performed in four patients with PJIs (four of 15), and débridement, antibiotics, and implant retention (DAIR) was performed in 11 patients (11 of 15) with PJIs. We performed Kaplan-Meier survivorship analysis for reinfection and revision procedures. Thirteen patients had a minimum of 2 years' followup and were included in the clinical analysis. Median followup was 4 years (range, 2-6 years). We calculated KSS. RESULTS: Infection-free survivorship was 71% at 5 years (95% confidence interval [CI], 46%-96%). Treatment success was higher for patients undergoing two-stage exchange (100% at 5 years; 95% CI, 100%-100%) versus DAIR (61% at 5 years; 95% CI, 31%-92%). Four of 11 patients undergoing DAIR had developed a reinfection at final followup. Survivorship free of any revision was 49% at 5 years (95% CI, 19%-79%). One patient from the two-stage exchange cohort underwent femoral component revision for aseptic loosening 5 years after PJI treatment, and two patients from the DAIR group were converted to TKA for disease progression at a mean of 4 years. In patients with a minimum of 2 years' followup, median KSS improved from 73 (range, 50-93) before index UKA to 94 (range, 55-100; p = 0.016). CONCLUSIONS: Treatment of UKA PJI with DAIR was associated with a lower infection-free survivorship at 5 years compared with two-stage exchange with conversion to TKA. Among those patients who were infection-free, a number needed reoperations for disease progression (in the DAIR group) or component loosening (in both groups). UKA PJI results in substantial morbidity, and patients with these infections should be followed closely for aseptic causes of failure in addition to infection recurrence. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Periprosthetic Joint Infection With Fungal Pathogens.

BACKGROUND: Although there is abundant information about bacterial periprosthetic joint infections (PJIs), there is a notable paucity of information about fungal PJIs. The goals of this study are to describe the patient demographics, diagnostic findings, and treatment results of fungal PJIs after total joint arthroplasty. METHODS: We identified 31 fungal PJIs (13 total hip arthroplasties and 18 total knee arthroplasties) in 31 patients treated between 1996 and 2014. This represented 0.9% of the 3525 PJIs treated at our institution during this time period. Candida species accounted for 81% of infections. The mean patient age at diagnosis of fungal PJI was 68 years. Mean follow-up after initiation of treatment was 4 years. RESULTS: In the total hip arthroplasty cohort, survivorship free from all-cause revision or implant removal was 44% at 2 years. Survivorship free from reinfection was 38% at 2 years. Mean Harris hip score was 27 at final follow-up.In the total knee arthroplasty cohort, survivorship free from all-cause revision was 70% at 2 years. Survivorship free from reinfection was 76% at 2 years. Mean Knee Society scores were 36 at final follow-up. CONCLUSION: Fungal PJIs are rare (0.9% of diagnosed PJIs). Survivorship free of all-cause revision or implant removal was very low in the hip group (44% at 2 years), but slightly better in the knee group (70% at 2 years). Moreover, clinical outcomes were poor with high perioperative complication rates. Improved treatment regimens are needed for this unsolved clinical problem.

Is There a Role for Preoperative Iron Supplementation in Patients Preparing for a Total Hip or Total Knee Arthroplasty?

BACKGROUND: Several treatment modalities exist for the treatment of perioperative anemia. We determined the effect of oral iron supplementation on preoperative anemia, and the use of blood-conserving interventions before total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: A total of 3435 total joint arthroplasties (1461 THAs and 1974 TKAs) were analyzed during 2 phases of a blood conservation program. The first phase used erythropoietin alfa (EPO) or intravenous (IV) iron for patients at risk for perioperative anemia. The second phase included these interventions, as well as preoperative iron supplementation. The effect on preoperative hemoglobin (Hb) and serum ferritin, as well as EPO and IV iron utilization, was determined. RESULTS: Oral iron therapy increased preoperative Hb level by 6 g/L (P < .001) and 7 g/L (P < .001) in the hip and knee cohorts, respectively. Serum ferritin level rose by 80 µg/L (P < .001) and 52 µg/L (P < .001) in the hip and knee cohorts, respectively. The number of patients with an Hb level <130 g/L was significantly reduced (P < .001 for both cohorts), as were patients with serum ferritin levels <35 µg/L (P = .002 for hip and P < .001 for knee cohorts). Utilization of EPO reduced from 16% to 6% (P < .001) and 18% to 6% (P < .001) in the hip and knee cohorts, respectively. Utilization of IV iron reduced from 4% to 2% (P = .05) and 5% to 2% (P < .001) in the hip and knee cohorts, respectively. CONCLUSION: Oral iron therapy reduced the burden of perioperative anemia and reduced utilization of other blood-conserving therapies before THA and TKA. Future research should delineate the cost-effectiveness of oral iron therapy.

Retained Antibiotic Spacers After Total Hip and Knee Arthroplasty Resections: High Complication Rates.

BACKGROUND: Prolonged retention of an antibiotic spacer is occasionally chosen during treatment of periprosthetic joint infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The purpose of our study was to evaluate the outcome of extended spacer retention. METHODS: We reviewed 1106 cases of periprosthetic joint infection after THA (n = 308) and TKA (n = 798) and identified 17 (5.5%) retained hip and 34 (4.3%) retained knee spacers. Most patients (35 of 51, 69%) underwent spacer retention because they were medically unfit for further surgery. The remaining patients (16 of 51, 31%) had acceptable function and forewent further surgery. Competing risk analyses, with death as the competing risk, determined the cumulative incidence of reinfection and spacer revision. Radiographic analysis and clinical outcomes were analyzed. RESULTS: The 2-year cumulative incidence for reinfection was 7% for retained hip and 13% for retained knee spacers. The cumulative incidence for all-cause spacer revision was 28% at 4 years for hips and 21% at 2 years for knees. The most common complications were implant migration and femoral spacer subsidence in the hip cohort, and supracondylar femur fractures and spacer dislocations in the knee cohort. The cumulative incidence for radiographic signs of mechanical failure was 72% and 87% at late follow-up for the hip and knee groups, respectively. The latest Harris Hip Score and Knee Society Score were 62 and 63, respectively. CONCLUSION: Antibiotic spacer retention is a rare event in the course of planned 2-stage treatment of infected THA or TKA. Failure secondary to recurrent infection is uncommon; however, failure for mechanical reasons is frequent and clinical outcomes are relatively poor.

In-Hospital Cost Analysis of Total Hip Arthroplasty: Does Surgical Approach Matter?

The purposes of this study were to determine the impact of surgical approach on costs of total hip arthroplasty (THA) from a hospital perspective and to provide an updated cost estimation of THA. A prospective, microcosting analysis was performed on 118 patients undergoing a THA through an anterior, lateral, or posterior approach. We determined that overall costs (intraoperative costs and hospital stay) were significantly less for the anterior ($7300.22; 95% confidence interval [CI], 7064.49-7535.95) vs lateral ($7853.10; 95% CI, 7577.29-8128.91; P = .031) and anterior vs posterior approach ($8287.46; 95% CI, 7906.42-8668.51; P < .001). A reduction in hospital length of stay when THA was performed through an anterior approach contributed significantly to an overall reduction in costs from a hospital perspective.

Perioperative Predictors of Length of Stay After Total Hip Arthroplasty.

BACKGROUND: Few studies had examined whether specific patient variables or performance on functional testing can predict length of stay (LOS) after total hip arthroplasty (THA). Such tools would enable providers to minimize prolonged LOS by planning appropriate discharge dispositions preoperatively. METHODS: We prospectively recruited 120 patients undergoing a THA through an anterior (n = 40), posterior (n = 40), or lateral (n = 40) approach. Patients performed a timed up-and-go (TUG) test preoperatively to determine if it was predictive of hospital LOS after THA. Other variables of interest included patient age, body mass index, age-adjusted Charlson Comorbidity Index, mean procedure time, and time spent in the postanesthetic care unit. A logistic regression analysis was performed to determine which variables predicted LOS greater than 48 hours, which is our institution's target time to discharge. RESULTS: The TUG test was predictive of LOS beyond 48 hours. For every 5-second interval increase in TUG time, patients were twice as likely to stay in hospital beyond 48 hours (odds ratio [OR] = 2.02, 95% confidence interval [CI] = 1.02-4.01, P = .043). Patient age (OR = 0.97, 95% CI = 0.90-1.05, P = .46), body mass index (OR = 1.01, 95% CI = 0.86-1.18, P = .90), Charlson Comorbidity Index (OR = 1.29, 95% CI = 0.68-2.44, P = .44), mean procedure time (OR = 1.05, 95% CI = 0.97-1.14, P = .27), and mean time in the postanesthetic care unit (OR = 1.00, 95% CI = 0.99-1.00, P = .94) were not predictive of increased LOS. CONCLUSION: The TUG test was predictive of hospital LOS after THA. It is a simple functional test that can be used to assist with discharge planning preoperatively to minimize extended hospital stays.

Mid-term survivorship and clinical outcomes of cobalt-chrome and oxidized zirconium on highly crosslinked polyethylene.

BACKGROUND: The choice of bearing articulation for total hip arthroplasty in younger patients is amenable to debate. We compared mid-term patient-reported outcomes and survivorship across 2 different bearing articulations in a young patient cohort. METHODS: We reviewed patients with cobalt-chrome or oxidized zirconium on highly crosslinked polyethylene who were followed prospectively between 2004 and 2012. Kaplan-Meier analysis was used to determine predicted cumulative survivorship at 5 years with all-cause and aseptic revisions as the outcome. We compared patient-reported outcomes, including the Harris hip score (HHS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Short-form 12 (SF-12) scores. RESULTS: A total of 622 patients were followed during the study period. Mean follow-up was 8.2 (range 2.0-10.6) years for cobalt-chrome and 7.8 (range 2.1-10.7) years for oxidized zirconium. Mean age was 54.9 ± 10.6 years for cobalt-chrome and 54.8 ± 10.7 years for oxidized zirconium. Implant survivorship was 96.0% (95% confidence interval [CI] 94.9%-97.1%) for cobalt-chrome and 98.7% (95% CI 98.0%-99.4%) for oxidized zirconium on highly crosslinked polyethylene for all-cause revisions, and 97.2% (95% CI 96.2%-98.2%) for cobalt-chrome and 99.0% (95% CI 98.4%-99.6%) for oxidized zirconium for aseptic revisions. An age-, sex- and diagnosis-matched comparison of the HHS, WOMAC and SF-12 scores demonstrated no significant changes in clinical outcomes across the groups. CONCLUSION: Both bearing surface couples demonstrated excellent mid-term survivorship and outcomes in young patient cohorts. Future analyses on wear and costs are warranted to elicit differences between the groups at long-term follow-up.

CONTEXTE: Le choix de la surface d'appui à utiliser dans une arthroplastie totale de la hanche chez de jeunes patients ne fait pas l'unanimité. Nous avons comparé les résultats déclarés par les patients et la survie à moyen terme associés à 2 surfaces d'appui différentes dans une cohorte de jeunes patients. MÉTHODES: Nous avons étudié les cas de patients ayant reçu une prothèse de chrome-cobalt ou de zirconium oxydé couplé au polyéthylène hautement réticulé suivis de façon prospective entre 2004 et 2012. La méthode de Kaplan­Meier a été employée pour déterminer la survie cumulative estimée après 5 ans dans les cas où le résultat est soit la reprise toutes causes confondues, soit la reprise aseptique. Nous avons comparé les résultats déclarés par les patients, notamment au moyen du score de Harris (HHS), de l'indice WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) et des scores issus de la version courte du questionnaire d'évaluation de l'état de santé général SF-12. RÉSULTATS: Au total, 622 patients ont été suivis durant la période de l'étude. En moyenne, le suivi a duré 8,2 ans (plage de 2,0 à 10,6 ans) pour le chrome-cobalt et 7,8 ans (plage de 2,1 à 10,7 ans) pour le zirconium oxydé. L'âge moyen des patients était de 54,9 ± 10,6 ans pour le chrome-cobalt et de 54,8 ± 10,7 ans pour le zirconium oxydé. Le taux de survie de la prothèse était de 96,0 % (IC à 95 % 94,9­97,1 %) pour le chrome-cobalt et 98,7 % (IC à 95 % 98,0­99,4 %) pour le zirconium oxydé couplé au polyéthylène hautement réticulé dans les cas de reprises toutes causes confondues, et de 97,2 % (IC à 95 % 96,2­98,2 %) pour le chrome-cobalt et 99,0 % (IC à 95 % 98,4­99,6 %) pour le zirconium oxydé dans les cas de reprises aseptiques. Une comparaison appariée fondée sur l'âge, le sexe et le diagnostic réalisée entre le HHS, l'indice WOMAC et les scores au questionnaire SF-12 n'a démontré aucun changement significatif entre les groupes quant aux résultats cliniques. CONCLUSION: Les 2 types de surface d'appui ont produit un taux de survie à moyen terme très élevé et d'excellents résultats dans des cohortes de jeunes patients. Il y a lieu de réaliser des analyses sur l'usure et les coûts afin de mettre en évidence les différences entre les groupes suivis à long terme.

Comparing the long-term results of two uncemented femoral stems for total hip arthroplasty.

327 proximal and 185 extensively coated femoral stems with mean 10-year follow-up were reviewed. Implant survivorship, clinical outcomes, and radiographic analyses were compared. Kaplan-Meier implant survivorship was 97.5% for the proximal, and 98.8% for the extensively coated stem for stem-only revisions at 10-years. The proximally coated stem outperformed on the PCS arm of the SF-12 (P = 0.04) and stiffness arm of the WOMAC (P = 0.03). Otherwise, all clinical outcomes were comparable. Thigh pain incidence was 12.5% and 5.3% for the extensive versus proximally coated groups, respectively (P = 0.007). Radiographic review identified more severe stress shielding (P < 0.001) in the extensively coated stems. This study supports the long-term clinical track record of total hip arthroplasty using two different cementless stem designs.

Scar Perception After Two Surgical Approaches for Total Hip Arthroplasty.

BACKGROUND: There is a paucity of literature examining patients' and health-care providers' perception of surgical scars after total hip arthroplasty (THA). This study examined perception of surgical scars after direct anterior (DAA) or posterior approach (PA) for THA using validated scar-assessment scales. MATERIAL AND METHODS: Seventy-five DAA and 75 PA THA patients underwent scar assessment using the Patient Observer Scar Assessment Scale (POSAS) and Stony Brook Scar Evaluation Scales. Mean age was different between the cohorts (DAA 67 vs PA 62 years, P = .01). All patients had subcuticular running closure, secured with skin adhesive glue. Mean time from THA to scar assessment was 3.1 and 3.6 years for the DAA and PA groups, respectively (P = .18). RESULTS: Scar opinion on the POSAS patient-reported scale was graded closer to normal skin more often for DAA than for PA patients (P = .03). More irregularities were graded for the DAA scars on the POSAS observer scale (P = .02) and the Stony Brook Scar Evaluation Scales (P = .04). Age did not predict scar opinion on any of the scales (P > .05). Female gender and a history of keloids predicted poorer scar appearance (P = .001 and P = .02). Overall scar appearance was rated as "good" in 93% of the DAA and 91% of the PA patients (P = .63). CONCLUSION: Differences exist in DAA and PA scar perception based on validated scales. Future randomized trials in scar assessment may control for confounding variables such as age and gender, as well as potential biases when using scar assessment scales.

Catastrophic Vascular Injury After Total Knee Arthroplasty.

Vascular injury is a feared complication of any surgical procedure. This study examined the incidence of vascular injury during total knee arthroplasty (TKA), the circumstances and timing of injury intraoperatively, and acute management. Eighteen cases of catastrophic vascular injury after primary TKA (12 of 19,577; 0.06%) or revision TKA (6 of 4453; 0.1%) were identified. Catastrophic injury was defined as any vascular injury requiring vascular surgery. Chart review was performed to identify the timing of vascular injury, the injured blood vessel, and acute management. The Knee Society Score (KSS) was calculated. Mean follow-up was 8 years. Surgical indications included primary osteoarthritis for 12 cases, reimplantation for infection for 3 cases, and aseptic revision for 3 cases. Vessel injury included the popliteal artery in 10 cases, the popliteal artery and vein in 5 cases, and the popliteal vein in 3 cases. Thirteen injuries occurred during tibial preparation. Management included thrombectomy and reanastomosis in 15 cases and vessel bypass in 3 cases. One patient had thrombosis and limb ischemia 2 days after repair, requiring bypass. No amputations had occurred at late follow-up. Mean KSS was 74 at latest follow-up. Catastrophic vascular injury is more common after revision TKA (1 of 1000) than after primary TKA (6 of 10,000). Most injuries occur during tibial preparation. If identified quickly and addressed promptly by vascular surgery, limb salvage is likely. [Orthopedics. 2022;45(6):340-344.].

Patellar Bone-Grafting for Severe Patellar Bone Loss During Revision Total Knee Arthroplasty.

BACKGROUND: Treatment of severe patellar bone loss during revision total knee arthroplasty (TKA) is difficult. Patellar bone-grafting is a simple procedure that can improve patient outcomes following revision TKA. DESCRIPTION: The patient is prepared and draped in the usual sterile fashion. The previous longitudinal knee incision is utilized for exposure. Scar tissue is excised from the medial gutter. However, tissue in the lateral gutter is largely maintained. An assessment of the surrounding quadriceps and patellar scar tissue ensues. This tissue can be utilized to create an envelope for holding the bone graft in place. If insufficient tissue is present, fascia from the iliotibial band or vastus medialis, allograft fascia, or synthetics can be used.A careful assessment of component fixation and rotation is critical to the success of patellar bone-grafting. Component revision for aseptic loosening or malrotation should be performed in the usual fashion. During component revision, it is recommended to preserve any additional bone as autograft for the patellar bone-grafting procedure. Common sites of autograft harvest include the femoral box cut and proximal tibial resection.The patella is then addressed by carefully removing the previous implant to avoid additional bone loss. This step is performed with a combination of an oscillating saw, osteotomes, and high-speed burr. The retropatellar bone is then prepared by debriding excess soft tissue, cysts, or cement. A high-speed burr is then utilized to produce a punctate bleeding surface for bone-graft incorporation.The harvested tissue is closed around the perimeter of the patella with use of interrupted nonabsorbable sutures, leaving a window to pack in the bone graft. The bone graft (allograft and autograft) is morselized and place through the window.The optimal patellar thickness is variable. After packing the bone graft through the soft-tissue window, the thickness is measured with a caliper. It is recommended to acquire a thickness of >20 mm because bone-graft resorption and remodeling occur with knee range of motion. The remaining soft-tissue window is closed with use of nonabsorbable sutures. The knee is cycled through a range of motion to ensure optimal patellofemoral tracking. If necessary, a lateral release or medial soft-tissue advancement can be performed to ensure patellofemoral tracking is adequate. Finally, the wound is irrigated and closed in layers. ALTERNATIVES: Nonsurgical:Patellar knee braceHinged knee braceSurgical:Gull-wing osteotomyPatellar resurfacing with biconvex patellaBulk allograft reconstructionPartial or complete patellectomyPatelloplastyInterpositional arthroplastyTantalum metal-backed reconstruction. RATIONALE: There is a myriad of surgical options for severe patellar bone loss following TKA. Patellar bone-grafting is simple, reproducible, and relatively cost-effective1,2, and avoids the need for the amount of bone for reconstruction that may be required for metal-backed or biconvex patellar implants3,4. The procedure allows for the restoration of the quadriceps lever arm, which may not be restored with other techniques, such as gull-wing osteotomy or patellectomy5. Patellar bone-grafting avoids the cost and risks of disease transmission associated with allograft reconstruction6. Finally, the procedure provides excellent long-term survivorship and patient-reported outcomes. EXPECTED OUTCOMES: Following this procedure, patients should experience a reduction in knee pain and improved patient-reported outcomes2,6, with a prior study showing that the percentage of patients reporting anterior knee pain decreased from 51% to 27% following patellar bone-grafting. Patients also demonstrated an improvement in knee range of motion, with a mean increase in knee flexion of 7o and knee extension of 2o1. Complications related to this procedure are minimal. Bone stock restoration can be utilized for patellar resurfacing in the future1. Radiographically, patellar bone resorption, loss of patellar height, and patellar remodeling do occur; however, despite these radiographic changes, Knee Society scores increased from 50 to 85 at the time of the latest follow-up. IMPORTANT TIPS: Careful preoperative physical examination should document range of motion, areas of pain, and patellofemoral tracking and/or instabilityBe prepared to revise the femoral and/or tibial components if malrotated in order to optimize patellofemoral trackingRetain any autogenous bone harvested during component revision to use as patellar bone graftEnsure that allograft bone is available to ensure sufficient restoration of patellar thicknessConsider having allograft tissue available in the event that scar tissue in situ is not adequate to create an envelope for packing the bone graftA bleeding retropatellar surface prepared with a high-speed burr will increase the chance of bone incorporationA watertight closure of the soft-tissue envelope is critical to avoid loss of bone graft during knee range of motion.

Intravenous Tranexamic Acid Safely and Effectively Reduces Transfusion Rates in Revision Total Knee Arthroplasties.

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.

Polyethylene Liner and Femoral Head Exchange in Total Hip Arthroplasty: Factors Associated with Long-Term Success and Failure.

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. 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.

Long-Term Results of Patellar Bone-Grafting for Severe Patellar Bone Loss During Revision Total Knee Arthroplasty.

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.

Two-Stage Exchange Protocol for Periprosthetic Joint Infection Following Total Knee Arthroplasty in 245 Knees without Prior Treatment for Infection.

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 (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.

Long-Term Results of a 2-Stage Exchange Protocol for Periprosthetic Joint Infection Following Total Hip Arthroplasty in 164 Hips.

BACKGROUND: Limited data exist that show the long-term risks of reinfection and mechanical failure with a contemporary 2-stage exchange protocol for periprosthetic joint infection following total hip arthroplasty. The purpose of this study was to determine the long-term reinfection and mechanical failure rates of 2-stage exchange for periprosthetic joint infection after total hip arthroplasty. METHODS: We identified 164 hips (162 patients) with infection after total hip arthroplasty between 1991 and 2006 treated with a 2-stage exchange protocol with no prior treatment for periprosthetic joint infection. With regard to Musculoskeletal Infection Society diagnostic criteria, at least 1 major criterion or 4 of 6 minor criteria were fulfilled in 129 hips (79%). The cumulative incidence with a competing risk of death was calculated for reinfection, aseptic revisions, and all-cause revisions. The risk factors for reinfection were evaluated using Cox proportional hazards regression. Harris hip scores were calculated. The mean age at the time of spacer insertion was 68 years, and 35% of the patients were female. Excluding the patients with <2 years of follow-up, the mean follow-up was 12 years (range, 2 to 21 years). RESULTS: The cumulative incidence of recurrence of infection was 10% at 1 year, 14% at 5 years, and 15% at 10 and 15 years. Seventeen patients (11%) used chronic antibiotic suppression (>6 months), with 7 (41%) of these having recurrent infection at the time of the latest follow-up. Use of chronic antibiotic suppression was the only predictive factor for reinfection (hazard ratio, 4.5 [95% confidence interval (CI), 1.9 to 10.9]; p = 0.001). The cumulative incidence of aseptic femoral and acetabular revisions was 2.6% at 5 years and 3.3% at 10 and 15 years. The cumulative incidence of all-cause revisions was 15% at 5 years and 16% at 10 and 15 years. Dislocation was the most common complication, with 28 dislocations occurring in 20 patients (12%). The mean Harris hip score improved from 52 points prior to spacer insertion to 70 points at 15 years after reimplantation (p < 0.01). CONCLUSIONS: The rate of recurrence of infection of 15% for up to 15 years after total hip arthroplasty was similar to previous shorter-term reports of 2-stage exchange for periprosthetic joint infection. Surgeons should anticipate mitigating instability after reimplantation. Implant survivorship free of aseptic loosening and clinical outcomes were preserved for the long term. The role of chronic antibiotic suppression in the long-term treatment of periprosthetic joint infection requires further investigation. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Gait analysis following release of the short external rotators during an anterior approach for total hip arthroplasty.

BACKGROUND: Cadaveric and clinical studies suggest surgical release of the short external rotators is sometimes necessary to improve exposure during total hip arthroplasty (THA) using an anterior approach. The purpose of this study was to determine the impact of those surgical releases on gait following THA. METHODS: 15 patients undergoing THA using an anterior approach, anterior approach with surgical releases, or posterior approach underwent 3-D gait analysis preoperatively, and at 6 and 12 weeks postoperatively. At each time point, temporal parameters, kinematics, and kinetics were compared. The anterior approach was compared to the anterior approach cohort with surgical releases, and the surgical release cohort was compared to a posterior approach cohort. The mean change score between preoperative and 6 weeks, and 6-week to 12-week analyses were analysed. RESULTS: There were no demographic differences between the groups. There were no significant differences between the groups for the temporal parameters and kinematic analyses at either time point comparison. The surgical release cohort had a lower hip internal rotation moment compared to the anterior approach cohort for the 6- to 12-week comparison ( p = 0.05), and compared to the posterior approach cohort for the preoperative to 6-week ( p = 0.03) and 6- to 12-week comparison ( p = 0.02). CONCLUSION: Releasing the short external rotators during an anterior approach did not cause significant temporal and kinematic changes after THA. However, small changes in hip internal rotation moments can be expected. These findings should be correlated with patient-reported outcome measures to determine if these gait anomalies predict poor outcome following THA.