Childhood diseases involving the proximal femoral epiphysis often cause abnormalities that can lead to end-stage arthritis at a relatively young age and the need for total hip arthroplasty (THA). The young age of these patients makes hip resurfacing arthroplasty (HRA) an alternative and favorable option due to the ability to preserve femoral bone. Patients presenting with end-stage hip arthritis as sequelae of childhood diseases such as Legg-Calves-Perthes (LCP) and slipped capital femoral epiphysis (SCFE) pose altered femoral anatomy, making HRA more technically complicated. LCP patients can result in coxa magna, coxa plana and coxa breva causing altered femoral head-to-neck ratio. There can also be acetabular dysplasia along with the proximal femoral abnormalities. SCFE patients have altered femoral head alignment. In particular, the femoral head is rotated medially and posteriorly, reducing the anterior and lateral offset. Additionally, many of these patients have retained hardware, making resurfacing more complicated. We report findings of a cohort of patients, with history of either LCP or SCPE who underwent HRA to treat end-stage arthritis. Data was retrospectively collected for patients who had HRA for hip arthritis as a result of either LCP (n=67) or SCFE (n=21) between 2004 and 2014 performed by two surgeons. Demographic information, clinical examination and improvement was collected pre and postoperatively. Improvement was determined using Harris Hip Scores (HHS) and UCLA activity scores. Anteroposterior radiographs were measured pre and postoperatively to determine leg length discrepancy. Radiographs were inspected postoperatively for radiolucent lines, implant loosening and osteolysis. Kaplan-Meier survivorship for freedom from reoperation for any reason was calculated. Paired student t-tests were used to compare groups.INTRODUCTION
METHODS
The optimal surgical treatment for osteonecrosis of the femoral head has yet to be elucidated. To evaluate the role of femoral fixation techniques in hip resurfacing, we present a comparison of the results for two consecutive groups: Group 1 (75 hips) received hybrid hip resurfacing implants with a cemented femoral component; Group 2 (103 hips) received uncemented femoral components. Both groups received uncemented acetabular components. We retrospectively analyzed our clinical database to compare failures, reoperations, complications, clinical results, metal ion test results, and x-ray measurements. Using consecutive groups caused time interval bias, so we required all Group 2 patients be at least two years out from surgery; we compared results from two years and final follow-up.Background
Methods
Traditionally, an inpatient hospital stay has been required for joint replacement surgery. The three primary drivers of cost for joint replacement have been implant cost, other hospital charges and postoperative rehabilitation costs. The three primary reasons that have made hospitalization necessary are pain control, blood loss / transfusion, and monitoring patients with comorbidities. Advances in surgical technique, implants, comprehensive blood management, and multimodal pain management have allowed a marked reduction in the hospital stay required and have eliminated the need for extensive formal rehabilitation. The purpose of this study is to evaluate if hip resurfacing can be performed safely and cost-effectively as an outpatient procedure. We present the short-term outcome of our first 125 hip resurfacings done as an outpatient procedure performed by two experienced surgeons. Young patients without major medical co-morbidities were selected. The average age was 53±7 years old (range: 38 to 66), there were 98 men and 27 women. The mean ASA score was 1.7±0.5 (range 1 to 3). The diagnosis was OA in 92, dysplasia in 22, and osteonecrosis in 9, and trauma in 2. There were no major complications noted in the first 6 weeks postoperative. There was one ER visit, and there were no hospitalizations required.Purpose
Methods
Traditionally an inpatient hospital stay has been required for all joint replacement surgery. The three primary drivers of cost for joint replacement have been implant cost, other hospital charges and postoperative rehabilitation costs. The three primary reasons that have made hospitalization necessary are pain control, therapy and possible transfusion. Advances in surgical technique, implants, comprehensive blood management, and multimodal pain management have allowed a marked reduction in the hospital stay required, eliminated the need for extensive formal rehabilitation. The purpose of this study is to evaluate if hip resurfacing can be performed safely and cost-effectively as an outpatient procedure. We present the short-term outcome of our first 77 hip resurfacings done as an outpatient procedure performed by two experienced surgeons. Young patients without major medical co-morbidities were selected. The average age was 53±6 years old (range: 38 to 66), there were 57 men and 20 women. The mean ASA score was 1.6±0.5 (range 1 to 2). The diagnosis was OA in 56, dysplasia in 17, avascular necrosis in 2, and others in 2.Introduction
Methods
Adverse wear related failure (AWRF) after metal-on-metal hip resurfacing arthroplasty (HRA) has been described as a new failure mechanism. We describe the results of revision of these failures. Between July 1999 and Jan 2014, a single surgeon performed 3407 HRA. Nine (9/3407; 0.3%) cases in 8 patients were revised due to AWRF. In two additional revisions for AWRF the primary HRA was done elsewhere. There were a total of 11 revisions (9 women, 2 men) for AWRF cases reported in this study. The primary diagnoses were OA in 7 and dysplasia in 4. At the time of the primary surgery, the average age was 50±5 years and the average BMI was 27±4. The average femoral component sizes were 46±3mm. Only the acetabular component was revised in eight cases, both components were revised in 4 cases (revised to THA), three of these four used metal on metal bearings. A postop CT was requested for all patients after revision. 4 scans were of sufficient quality to analyze implant positions. Algorithms for metal artifact reduction were utilized to obtain high quality 2D images (Figure 1); 3D CAD models of the bones and implants were regenerated in order to calculate the acetabular inclination and anteversion angle (Figure 2).Introduction
Methods
A recent report based on the NARA database (Nordic Arthroplasty Register Association) found that the 10-year survivorship of patients under 50 with traditional total hip arthroplasty was only 83% in 14,600 cases. The purpose of this study was to compare our experience using metal-on-metal hip resurfacing arthroplasty (HRA) to treat these patients. from May 2001 to Feb 2012, a single surgeon performed 1029 metal-on-metal HRA in 855 patients younger than 50 years old. Three different implants were used in consecutive groups of patients, first the Corin hybrid HRA (182); then the Biomet hybrid HRA (306); and finally the Biomet uncemented HRA (541). The primary diagnoses were OA (707); dysplasia (125); osteonecrosis (98); post-trauma (28); Legg-Calve-Perthes (27) and others (44). The average age was 43±6 years; 74% were men; the average BMI was 27±4; mean femoral component size was 50±4 (range 40–62); the average T-score was 0±1. 37% of our patients reported a UCLA Activity level of 9 or 10 (impact sports). Six died with causes unrelated to their HRAs. The rate of follow-up was 94%. Our patients were not selected by any criteria except the surgeon's technical ability to perform an HRA.Introduction
Methods
Most metal-on-metal hip resurfacing implants currently being used worldwide utilize bone ingrowth fixation on the acetabular side, but cement fixation remains the standard method of fixation on the femoral side. Our hypothesis is that bone ingrowth fixation of a fully porous-coated component is superior to cement fixation of the femoral hip resurfacing component. From March 2007 to Jan 2009, 429 consecutive metal-on-metal hip resurfacing arthroplasties were performed by a single surgeon in 396 unselected patients using Biomet uncemented femoral and acetabular components. All of these were at least 5-years postop. Three patients died with causes unrelated to their hip arthroplasty. The three most common primary diagnoses were osteoarthritis in 318 (74%) cases, dysplasia in 66 (15%) hips, and osteonecrosis in 19 (4%) hips. The average size of the femoral component was 50 ± 4 cm. All pre-operative, intra-operative, and post-operative data were prospectively collected and entered into our database for review. All patients are allowed unrestricted activity including impact sports after 6 months.Introduction
Methods
761 cases in 613 patients with minimal two years follow-up had both metal ion levels and quality pelvis X-ray identified in our database and are included in this study. The UCLA activity score, femoral shaft angle, body mass index, weight, American Society of Anesthesiologists (ASA) score, combined range of motion (CROM), diagnosis, age, implant brand, gender, AIA, bearing size, and duration of implantation were analyzed to determine the potential risk factors for elevated metal ion levels with use of uni- and multi-variable logistic regression models. A safe zone for hip resurfacing (RAIL: Relative Acetabular Inclination Limit) was calculated based on implant size and AIA on AP pelvis X-ray. For AIA below the RAIL, there were no adverse wear failures or dislocations, and only 1% of cases with ion levels above 10 μg/L. We have not found a lower limit of AIA where failures occurred. Other than high inclination angle and small bearing size, female gender was the only other factor that correlated with high ion levels in the multivariate analysis. We have described the robust “safe zone” for acetabular component position based on metal ion levels in a large patient cohort for metal-on-metal hip resurfacing arthroplasty. Our study suggests that adverse wear failures with hip resurfacing may be highly predictable and avoidable. If the AIA is below the RAIL, rare dislocations are also prevented.
