Faculty Bibliography

Introduction/UNASSIGNED:This article describes our technique of adding a custom-made antibiotic-coated stem to an articulating spacer to improve fixation and effectively deliver antibiotics to the medullary canal in the treatment of infection following total knee arthroplasty. Step 1 Obtain Items Required for Intraoperative Assembly/UNASSIGNED:Make sure all required items are ready prior to the start of the operation. Step 2 Remove the Components and Perform Thorough Debridement/UNASSIGNED:Remove the components and debride all cement and necrotic, devitalized, and infected tissue. Step 3 Size the Spacers/UNASSIGNED:Use the polyethylene insert to size the tibial spacer and the anteroposterior dimension of the explanted femoral component to size the femoral spacer. Step 4 Construct the Stems/UNASSIGNED:Divide the rod, coat the rods with antibiotic cement, and connect them to the articulating components. Step 5 Implant the Spacers/UNASSIGNED:Apply the cement only to the metaphysis and undersurface of the tibial spacer and place a large amount of cement on the medial and lateral condyles of the femoral spacer. Step 6 Postoperative Protocol/UNASSIGNED:Patients should walk with partial weight-bearing with a brace locked in extension for three to four weeks. Results/UNASSIGNED:. What to Watch For/UNASSIGNED:IndicationsContraindicationsPitfalls & Challenges.

BACKGROUND: The Rejuvenate modular-neck stem implant (Stryker Orthopaedics, Mahwah, New Jersey) was recently recalled due to corrosion at the femoral neck-stem junction. The purpose of this study was to investigate the rate of corrosion-related failure and survivorship of this implant and analyze the correlation of implant and patient factors with serum metal ion levels and revisions. METHODS: From June 2009 to July 2012, 123 Rejuvenate total hip arthroplasty stems (ninety-seven modular and twenty-six non-modular) were implanted in 104 patients by a single surgeon. Serum cobalt (Co) and chromium (Cr) levels (micrograms per liter [mug/L]) were measured postoperatively for all patients. Patients with persistent hip pain or elevated metal ion levels underwent magnetic resonance imaging for assessment of osteolysis or adverse local tissue reactions. Correlation of implant factors (stem size, head size, head length, and femoral head-neck offset) and patient factors (age, sex, and body mass index) with serum metal ion levels and revisions were analyzed with use of logistic regression models. RESULTS: The mean duration of follow-up (and standard deviation) was 2.7 +/- 0.6 years. The mean Co and Cr levels were 5.4 +/- 5.7 mug/L (range, 0.2 to 31 mug/L) and 2.1 +/- 1.5 mug/L (range, 0.1 to 4.3 mug/L), respectively. The differences in Co and Cr levels between the two groups (modular and non-modular) were significant: 48% of the total hip arthroplasties in the modular group resulted in elevated metal ion levels (Co >4.0 mug/L and Cr >2.0 mug/L; p < 0.05). The metal ion levels in the non-modular group were normal. In the modular group, higher metal ion levels were significantly correlated with younger age and a higher femoral head-neck offset (p = 0.04). Pain and high Co serum levels were significant predictors of revision surgery (p = 0.006). The rate of revision at the time of this study was 28% in the modular group, with the majority of the revisions performed in the second year after surgery; the Kaplan-Meier survivorship was 40% at four years. CONCLUSIONS: The short-term high rate of corrosion-related revision with Rejuvenate modular-neck stems is striking.

BACKGROUND: A high hip center total hip arthroplasty (THA) for dysplasia allows more complete socket coverage by native bone at the expense of abnormal hip biomechanics. Despite poor results with cemented components, intermediate-term results with cementless cups at a high hip center have been promising, but there are few reports at long-term followup without bone graft. QUESTIONS/PURPOSES: The purpose of this study was to examine (1) survivorship; 2) radiographic results; and 3) hip scores at a minimum of 10 years for patients treated with high hip center cementless THA for Crowe II and III dysplasia without bone graft. METHODS: We reviewed charts and radiographs of 32 patients with Crowe II or III dysplasia who were treated with high hip center cementless THA; at a mean followup of 12 years (range, 10-21 years), 23 patients (27 hips) were available for review. We sought to medialize cups to the inner table to achieve bony coverage of > 75%. At final followup, the WOMAC and Harris hip scores were recorded. Radiographic analysis including computerized wear evaluation was performed. Radiographic parameters were compared with a control group of 23 patients with Crowe I dysplasia who had cementless cups placed at an anatomic hip center; among the high hip center reconstructions, we also compared wear between those in the superolateral and superomedial quadrants. RESULTS: Kaplan-Meier survivorship for all-cause revisions was 97% (95% confidence interval, 79%-99%) in the high hip center group; this was no different from the anatomic hip center group. There were no revisions for acetabular loosening. Wear rates did not differ significantly between the high hip center and the control group, but lateralized high hip centers were associated with higher (p = 0.002) wear. Hip scores were excellent in both groups. CONCLUSIONS: In Crowe II and III dysplasia, a high hip center cementless cup obviates the need for bone graft and provides durable fixation beyond 10 years. Medialization of these reconstructions seems important to decrease wear. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: Some orthopaedic procedures, including TKA, enjoy high survivorship but leave many patients dissatisfied because of residual pain and functional limitations. An important cause of patient dissatisfaction is unfulfilled preoperative expectations. This arises, in part, from differences between provider and patient in their definition of a successful outcome. WHERE ARE WE NOW?: Patients generally are less satisfied with their outcomes than surgeons. While patients are initially concerned with symptom relief, their long-term expectations include return of symptom-free function, especially in terms of activities that are personally important. While surgeons share their patients' desire to achieve their goals, they are aware this will not always occur. Conversely, patients do not always realize some of their expectations cannot be met by current orthopaedic procedures, and this gap in understanding is an important source of discrepancies in expectations and patient dissatisfaction. WHERE DO WE NEED TO GO?: An essential prerequisite for mutual understanding is information that is accurate, objective, and relevant to the patient's condition and lifestyle. This critical information must also be understandable within the educational and cultural background of each patient to enable informed participation in a shared decision making process. Once this is achieved, it will become easier to formulate similar expectations regarding the likely level of function and symptom relief and the risk of adverse events, including persistent pain, complications, and revision surgery. HOW DO WE GET THERE?: Predictive models of patient outcomes, based on objective data, are needed to inform decision making on the individual level. This can be achieved once comprehensive data become available capturing the lifestyles of patients of diverse ages and backgrounds, including data documenting the frequency and intensity of participation in sporting and recreational activities. There is also a need for greater attention to the process of informing patients of the outcome of orthopaedic procedures, not simply for gaining more meaningful consent, but so that patients and providers may achieve greater alignment of expectations and increased acceptance of both the benefits and limitations of alternative treatments.

This is the first long-term (mean 11.6years), prospective, matched-pair study (based on age, gender, BMI and UCLA scores) using MAVRIC (multi-acquisition variable-resonance image combination) magnetic resonance imaging to analyze reactive synovitis and osteolysis between rotating-platform posterior-stabilized (RP-PS), fixed-bearing metal-back (FB-MB), and all-polyethylene tibial (APT) in active patients (24 total, 8 in each group, mean age of 64years, mean UCLA of 8.5) with identical femoral component and polyethylene. Reactive synovitis was observed in 6 RP-PS (75%), all 8 FB-MB (100%), and 6 APT (75%). There was a significant difference between the RP-PS and FB-MB knees in volumetric synovitis (P=0.023). Osteolysis with bone loss more than 4mm was seen in 3 FB-MB, 2 APT and none for RP-PS. These were not statistically significant.

The aim of this study was to assess peri-operative complications, safety and efficacy of non-cemented femoral fixation in total hip arthroplasty (THA) as compared to cemented femoral fixation in the elderly population. Fifty-two matched pair analysis of patients with 75 years of age and older (104 patients), who underwent primary THA from June 1997 to December 2004, was performed based on age, sex, BMI, and Charnley classification. Mean age was 81 years (75-101) and the average follow up was 3.1 +/- 2.9 years (1.2-6.4). There was no difference in peri-operative cardiopulmonary complications, pulmonary failures, deep venous thrombosis, pulmonary embolus, length of stay, or discharge deposition between the two groups. Non-cemented fixation is safe and effective in patients older than 75 years of age.

BACKGROUND: Data regarding outcomes following intralesional curettage and cryosurgical treatment of low-grade chondrosarcoma of bone are limited. The aim of this study was to assess the long-term oncologic and functional outcomes of two different cryosurgery techniques. METHODS: Forty-three low-grade chondrosarcoma lesions (in forty-two patients) were treated with intralesional curettage and cryosurgery from June 1983 to October 2006. Eleven lesions were treated with cryoprobes and thirty-two were treated with the modified direct-pour Marcove technique. The mean patient age was 44.9 +/- 11.3 years (range, 21.8 to 66.4 years), and the mean duration of follow-up was 10.2 +/- 4.6 years (range, five to 22.5 years). Indications for treatment included a radiographic appearance consistent with a cartilage tumor with evidence of aggressive behavior. Pearson correlation and multivariate analyses were used to evaluate the relationships between predictive factors (including lesion size, soft-tissue extension, and location, patient age, cortical erosion, and presence of preoperative pain) and outcomes. RESULTS: The mean overall Musculoskeletal Tumor Society (MSTS) score was 26.5 +/- 3.1 (range, 17 to 30). There were four local recurrences, all in patients who had had tumor extension out of the bone with soft-tissue involvement at initial presentation. The mean time to recurrence was 2.4 +/- 2.3 years (range, 0.6 to 5.6 years). No patients developed metastatic disease during the follow-up period. There were no differences between the cryoprobe and Marcove techniques with respect to the MSTS score, fracture, or local recurrence. A significant correlation between tumor recurrence and soft-tissue extension was found (r = 0.79). Kaplan-Meier survivorship, with freedom from recurrence as the end point, was 90.7%. CONCLUSIONS: Intralesional curettage and cryosurgery for low-grade chondrosarcoma is safe and effective in selected patients. The presence of preoperative cortical breakthrough and soft-tissue extension was the strongest predictor of local recurrence following use of this technique. LEVEL OF EVIDENCE: Therapeutic level IV. See instructions for authors for a complete description of levels of evidence.

Cup positioning is an important variable for short and long term function, stability, and durability of total hip arthroplasty (THA). This novel method utilizes internal and external bony landmarks, and the transverse acetabular ligament for positioning the acetabular component. The cup is placed parallel and superior to the transverse ligament and inside the anterior wall notch of the true acetabulum, then adjusted for femoral version and pelvic tilt and obliquity based on weight bearing radiographs. In 78 consecutive THAs, the mean functional anteversion and abduction angles were 17.9 degrees +/- 4.7 degrees and 41.7 degrees +/- 3.8 degrees , respectively. 96% of the functional anteversion measurements and 100% of the functional abduction angles were within the safe zone. This technique is an easy, reproducible, and accurate method for functional cup placement.

BACKGROUND: Ceramic femoral heads produce less wear of the opposing polyethylene than do metal femoral heads in wear simulation studies. This is a matched-pair analysis of the wear of ceramic and metal femoral heads on conventional polyethylene in uncemented total hip replacements in young, active patients at a minimum of fifteen years of follow-up. METHODS: From June 1989 to May 1992, thirty-one matched pairs of alumina ceramic or cobalt-chromium metal femoral heads were identified. Patients were matched on the basis of age, sex, body weight, diagnosis, and activity level. The mean age was 55 +/- 9 years (range, twenty-three to sixty-five years) at the time of surgery. All procedures were performed with a posterolateral surgical approach by a single surgeon using press-fit Ranawat-Bernstein femoral stems, Harris-Galante-II acetabular cups, GUR 4150 conventional polyethylene (sterilized in argon), and 28-mm-diameter femoral heads. Wear measurements were performed by two independent observers using the computer-assisted Roman software. RESULTS: The average duration of follow-up was 17 +/- 1.7 years (range, fifteen to twenty years). The mean Hospital for Special Surgery hip scores (and standard deviation) in the ceramic and metal groups were 39 +/- 4 and 40 +/- 3 at the time of final follow-up. The University of California Los Angeles activity score at the time of the final follow-up was 6 +/- 2 for both groups. The mean wear rates for the ceramic group and the metal group were 0.086 +/- 0.05 mm/yr and 0.137 +/- 0.05 mm/yr, respectively (p = 0.0015). There was one reoperation in the ceramic group because of distal femoral osteolysis. There were three failures in the metal group, requiring isolated liner exchange in two hips and revision of the acetabular component in one hip because of wear-induced osteolysis and/or loosening that caused symptoms. Five hips in the ceramic group and six hips in the metal group had radiographic evidence of acetabular or femoral osteolysis, but none were symptomatic. CONCLUSIONS: Ceramic femoral heads produced significantly less wear on conventional polyethylene liners at the time of long-term follow-up than did metal heads in this matched-pair analysis of young and active patients with uncemented fixation.