Comparison of Existing and New Total Knee Arthroplasty Implant Systems From the Same Manufacturer: A Prospective, Multicenter Study.

INTRODUCTION: This study evaluated total knee arthroplasty (TKA) outcomes for an Existing-TKA versus New-TKA from the same manufacturer. METHODS: TKA outcomes for 752 with Existing-TKA versus 1129 subjects with New-TKA were followed through 2 years using patient-reported outcome measures (PROMs). Responders were assessed per Outcome Measures in Rheumatology-Osteoarthritis Research Society International criteria. Kaplan-Meier implant survivorship was estimated. Radiographs had an independent radiographic review. RESULTS: Two-year follow-up was 84.6% (636/752) for Existing-TKA and 82.5% (931/1129) for New-TKA. Two-year PROMs mean outcomes for New-TKA versus Existing-TKA at 2 years were: Knee Injury and Osteoarthritis Outcome Score (ADL: 89.0 versus 86.8, P = 0.005; pain: 88.9 versus 87.1, P = 0.019; symptoms: 84.1 versus 82.2, P = 0.017; Sport/Rec: 63.9 versus 58.8, P = 0.001; and QOL: 77.0 versus 73.5, P = 0.003), Patient's Knee Implant Performance (overall: 76.5 versus 73.5, P = 0.003; confidence: 8.4 versus 8.1, P = 0.004; stability: 8.6 versus 8.3, P = 0.006; satisfaction: 8.3 versus 8.1, P = 0.042; and modifying activities: 6.6 versus 6.4, P = 0.334), Oxford Knee Score (41.9 versus 41.1, P = 0.027), and EQ5D-3L (0.88 versus 0.88, P = 0.737). Two-year responder rates using WOMAC were 93.9% versus 90.6% (P = 0.018) for New-TKA versus Existing-TKA. Independent radiographic review showed that tibial and femoral radiolucencies ≥2 mm were similar (P ≥ 0.05) or favored New-TKA. Implant survivorship was similar between groups (log-rank P = 0.9994). DISCUSSION: New-TKA versus Existing-TKA demonstrated slightly better PROMs with similar radiographic and implant survivorship outcomes.

Preoperative body mass index and physical function are associated with length of stay and facility discharge after total knee arthroplasty.

BACKGROUND: Hospital length of stay (LOS) and facility discharge are primary drivers of the cost of total knee arthroplasty (TKA). We sought to identify modifiable patient factors that were associated with increased LOS and facility discharge after TKA. METHODS: Prospective data were reviewed from 716 consecutive, primary TKA procedures performed by two arthroplasty surgeons between 2006 and 2012 at a single institution. Preoperative body mass index (BMI), Veterans RAND-12 (VR-12) physical component score (PCS), and hemoglobin level were collected in addition to other adjusters. Multivariate linear and logistic models were constructed to predict LOS and facility discharge, respectively. RESULTS: After adjustment, higher BMI was associated with increased LOS in a dose-response effect: Compared to normal weight (BMI <25) overweight (25-29.9) was associated with longer LOS by 0.32days (P=0.038), class-I obesity (30-34.9) by 0.33days (P=0.024), class-II obesity (35-39.9) by 0.67days (P=0.012) and class-III obesity (>40) by 1.15days (P<0.001). Class-III obesity was associated with facility discharge (odds ratio=2.08, P=0.008). Poor PCS was associated with increasing LOS: compared to PCS≥50, PCS 20-29 was associated with a LOS increase of 0.40days (P=0.014) and PCS<20 with a LOS increase of 0.64days (P=0.031). CONCLUSION: Patient BMI has a dose-response effect in increasing LOS. Poor PCS was associated similarly with increased LOS. These associations for of BMI and PCS suggest that improvement preoperatively, by any amount, may potentially translate to decreased LOS and perhaps lower the cost associated with TKA.

Early Patient Outcomes After Primary Total Knee Arthroplasty with Quadriceps-Sparing Subvastus and Medial Parapatellar Techniques: A Randomized, Double-Blind Clinical Trial.

BACKGROUND: Techniques that reduce injury to the knee extensor mechanism may cause less pain and allow faster recovery of knee function after primary total knee arthroplasty. A quadriceps-sparing (QS) subvastus technique of total knee arthroplasty was compared with medial parapatellar arthrotomy (MPPA) to determine which surgical technique led to better patient-reported function and less postoperative pain and opioid utilization. METHODS: In this prospective, double-blind study, 129 patients undergoing total knee arthroplasty were randomized to the QS or the MPPA group after skin incision. All surgical procedures utilized minimally invasive surgery principles and standardized anesthesia, implants, analgesia, and rehabilitation. The Knee Society Score (KSS) was obtained at baseline and one and three months after surgery. Weekly telephone interviews were used to collect patient-reported outcomes including ambulatory device use, the UCLA (University of California Los Angeles) activity score, performance of daily living activities, and opioid utilization. RESULTS: No differences between groups were seen in opioid utilization, either during the acute hospitalization or in the eight weeks after surgery. The QS group reported significantly less pain at rest on postoperative day one and with activity on day three (p = 0.04 for each). Compared with baseline, both groups showed significant improvements in the KSS at one month (MPPA, p = 0.0278; QS, p = 0.0021) and three months (p < 0.0001 for each) as well as week-to-week gains in walking independence through five weeks after surgery. Independence from ambulatory devices outside the home lagged behind independence indoors by about two weeks in both groups. CONCLUSIONS: When primary total knee arthroplasty was performed with contemporary minimally invasive surgery principles and standardized implants, anesthesia, and postoperative pathways, the QS technique yielded no significant early functional advantages or differences in opioid utilization compared with the MPPA technique. However, the mean pain scores reported by patients in the QS group were slightly lower at rest on postoperative day one and during activity on day three. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Cost-effectiveness of preoperative nasal mupirocin treatment in preventing surgical site infection in patients undergoing total hip and knee arthroplasty: a cost-effectiveness analysis.

OBJECTIVE: To perform a cost-effectiveness analysis to evaluate preoperative use of mupirocin in patients with total joint arthroplasty (TJA). DESIGN: Simple decision tree model. SETTING: Outpatient TJA clinical setting. PARTICIPANTS: Hypothetical cohort of patients with TJA. INTERVENTIONS: A simple decision tree model compared 3 strategies in a hypothetical cohort of patients with TJA: (1) obtaining preoperative screening cultures for all patients, followed by administration of mupirocin to patients with cultures positive for Staphylococcus aureus; (2) providing empirical preoperative treatment with mupirocin for all patients without screening; and (3) providing no preoperative treatment or screening. We assessed the costs and benefits over a 1-year period. Data inputs were obtained from a literature review and from our institution's internal data. Utilities were measured in quality-adjusted life-years, and costs were measured in 2005 US dollars. MAIN OUTCOME MEASURE: Incremental cost-effectiveness ratio. RESULTS: The treat-all and screen-and-treat strategies both had lower costs and greater benefits, compared with the no-treatment strategy. Sensitivity analysis revealed that this result is stable even if the cost of mupirocin was over $100 and the cost of SSI ranged between $26,000 and $250,000. Treating all patients remains the best strategy when the prevalence of S. aureus carriers and surgical site infection is varied across plausible values as well as when the prevalence of mupirocin-resistant strains is high. CONCLUSIONS: Empirical treatment with mupirocin ointment or use of a screen-and-treat strategy before TJA is performed is a simple, safe, and cost-effective intervention that can reduce the risk of SSI. S. aureus decolonization with nasal mupirocin for patients undergoing TJA should be considered. LEVEL OF EVIDENCE: Level II, economic and decision analysis.

Cost-effectiveness of antibiotic-impregnated bone cement used in primary total hip arthroplasty.

BACKGROUND: Antibiotic-impregnated bone cement is infrequently used in the United States for primary total hip arthroplasty because of concerns about cost, performance, and the possible development of antibiotic resistance and because it has been approved only for use in revision arthroplasty after infection. The purpose of this study was to model the use of antibiotic-impregnated bone cement in primary total hip arthroplasty for the treatment of osteoarthritis to determine whether use of the cement is cost-effective when compared with the use of cement without antibiotics. METHODS: To evaluate the cost-effectiveness of each strategy, we used a Markov decision model to tabulate costs and quality-adjusted life years (QALYs) accumulated by each patient. Rates of revision due to infection and aseptic loosening were estimated from data in the Norwegian Arthroplasty Register and were used to determine the probability of undergoing a revision arthroplasty because of either infection or aseptic loosening. The primary outcome measure was either all revisions or revision due to infection. Perioperative mortality rates, utilities, and disutilities were estimated from data in the arthroplasty literature. Costs for primary arthroplasty were estimated from data on in-hospital resource use in the literature. The additional cost of using antibiotic-impregnated bone cement ($600) was then added to the average cost of the initial procedure ($21,654). RESULTS: When all revisions were considered to be the primary outcome measure, the use of antibiotic-impregnated bone cement was found to result in a decrease in overall cost of $200 per patient. When revision due to infection was considered to be the primary outcome measure, the use of the cement was found to have an incremental cost-effectiveness ratio of $37,355 per QALY compared with cement without antibiotics; this cost-effectiveness compares favorably with that of accepted medical procedures. When only revision due to infection was considered, it was found that the additional cost of the antibiotic-impregnated bone cement would need to exceed $650 or the average patient age would need to be greater than seventy-one years before its cost would exceed $50,000 per QALY gained. CONCLUSIONS: When revision due to either infection or aseptic loosening is considered to be the primary outcome, the use of antibiotic-impregnated bone cement results in an overall cost decrease. When only revision due to infection is considered, the model is strongly influenced by the cost of the cement and the average age of the patients. With few patients less than seventy years of age undergoing total hip arthroplasty with cement in the United States, the use of antibiotic-impregnated bone cement in primary total hip arthroplasty may be of limited value unless its cost is substantially reduced.

Pelvic and femoral osteotomy in the treatment of hip disease in the young adult.

Osteotomies of the pelvis and upper femur play a useful and enduring role in the overall management of posttraumatic and developmental conditions of the hip. Rotational osteotomies of the pelvis have supplanted intertrochanteric osteotomies for treatment of most dysplasia-related conditions. In particular, the Bernese (Ganz) periacetabular osteotomy with lateral muscle sparing has emerged as the most effective and widely used pelvic osteotomy. Other methods, such as the Tönnis juxta-articular and triple innominate, also can be successful. These procedures have a risk profile that demands respect for the possible occurrence of significant complications and outcomes that are not uniformly excellent. Once significant arthritis is present, total hip arthroplasty is the procedure of choice in most instances. On the femoral side, the effectiveness of valgus osteotomy for femoral neck nonunion is unquestioned. Precollapse osteonecrosis is not a contraindication. Limb-length inequalities, malrotations, and displacements of posttraumatic deformities can be uniquely benefited by intertrochanteric osteotomy. Grade II slipped capital femoral epiphysis, Legg-Calvé-Perthes disease, and osteonecrosis sometimes can be effectively treated with intertrochanteric osteotomy. All osteotomies should be planned and performed in a manner that anticipates the possible need for future conversion to total hip replacement.

The role of acetabular and femoral osteotomies in reconstructive surgery of the hip: 2005 and beyond.

Femoral and acetabular osteotomies have enduring and useful roles in the ongoing surgical treatment of patients with various hip conditions. The classic indication for intertrochanteric valgus osteotomy is to induce healing of femoral neck nonunions. Additional indications include posttraumatic deformity, limb-length inequality, certain cases of osteonecrosis, and adult sequelae of Legg-Calve-Perthes disease, and slipped capital femoral epiphysis. Isolated intertrochanteric osteotomy is only occasionally indicated for the treatment of arthritis secondary to dysplasia. Rotational osteotomies of the pelvis have overtaken the role once historically played by intertrochanteric osteotomy in the treatment of dysplasia-related hip anomalies. Ideal candidates have prearthritic, activity-related pain associated with radiographic dysplasia. It is imperative that the hip joint be congruous, free of fixed subluxation, and located in the natural acetabulum. Surgical treatment of associated acetabular labral tears and/or detachments and impingement lesions can be done at the same time through antecedent hip arthroscopy (same anesthetic) or open arthrotomy. The direction and magnitude of correction need to be customized to fit the nature of the dysplasia. A standard method of correction likely is to result in unwanted iatrogenic retroversion in some cases. Intertrochanteric osteotomy now is used as a complement to rotational osteotomy for the indications outlined above.

Intertrochanteric femoral osteotomies for developmental and posttraumatic conditions.

Despite the numerous advances in technology and techniques for total hip arthroplasty, this surgery is often not the procedure of choice for all patients or for all hip conditions. Originally described as a treatment for femoral neck nonunions, the intertrochanteric femoral osteotomy retains an enduring role in the treatment of various posttraumatic and developmental hip conditions including femoral neck nonunions, iatrogenic or postsurgical deformities, leg-length inequality, osteonecrosis, slipped capital femoral epiphysis, deformities occurring after Legg-Calvé-Perthes desease, and for certain patients with dysplasia and secondary arthritis. By correcting deformity (either acquired or developmental), the intertrochanteric osteotomy can restore a more normal biomechanical geometry to the hip joint, which can increase the likelihood of improved longevity of the articulation. Excellent results have been reported by numerous authors using this procedure alone or in association with simultaneous or staged osteotomy of the pelvis. Factors that are common to most successful series are an emphasis on proper patient selection, detailed preoperative step-by-step planning, and meticulous intraoperative technique. Surgical intervention prior to the development of irreversible articular deterioration may result in dramatic short-term relief of pain because of improvements in biomechanics and relief of impingement. Long-term results include elimination of the need for total hip arthroplasty or postponement o f the need for this surgery for a meaningful number of years (such as 10 years or more).

Late infection of a total knee arthroplasty with Streptococcus bovis in association with carcinoma of the large intestine.

Infection of a total knee arthroplasty with Streptococcus bovis in a 76-year-old man that led to the diagnosis of a bowel carcinoma is reported. Investigation revealed a malignancy in the ascending colon with extension into the adrenal gland. S bovis in conjunction with colonic neoplasia has been reported in several orthopedic conditions: vertebral osteomyelitis, discitis, lateral neck abscess, and osteomyelitis of the ileum. The relationship of S bovis to endocarditis, meningitis, brain abscesses, and peritonitis has also been well described. However, S bovis is a rare pathogen infecting joint prostheses and should raise the possibility of a gastrointestinal lesion.