Short-term Results of Birmingham Hip Resurfacing in the United States.

Previous data on the survivorship of the Birmingham Hip Resurfacing (BHR) implant have come from design surgeons and large national databases outside of the United States, and there is a lack of reported outcomes of surface replacement arthroplasty from US centers. A retrospective study was undertaken of 1271 hips treated with a BHR system (Smith & Nephew, Memphis, Tennessee) between June 2006 and September 2008 at 6 high-volume total joint centers in the United States. Demographic features, Harris Hip Score (HHS), and radiographic findings were recorded. Patients who did not have a 2-year follow-up visit were contacted by telephone. All patients were asked about complications, reoperations, or failure of the implants. Of the treated hips, 1144 (90%) had a minimum of 2 years of clinical follow-up (mean, 2.9 years; range, 1.8-4.2 years). Mean age was 52.3 years, and 75% of patients were men. Mean HHS improved from 55.8 preoperatively to 97.4 at the most recent follow-up (P<.001). There were 16 (1.4%) revisions to total hip arthroplasty (THA) for fracture (7), early dislocation (3), acetabular component malpositioning with pain (3; 1 with metallosis), infection (1), femoral loosening (1), and pseudotumor (1). There were 9 additional complications (0.8%) that did not require revision, including 3 dislocations treated with closed reduction, 2 fractures, 3 nerve injuries, and 1 pseudotumor. At 2 to 4 years of follow-up, the revision rate and the major complication rate with the BHR system were similar to those in previous reports of primary THA. Excellent clinical results were observed, but further follow-up is necessary to assess mid- and long-term results with the BHR system in US patients.

Lack of early dislocation following total hip arthroplasty with a new dual mobility acetabular design.

Dual mobility implant designs minimise the risk of dislocation without sacrificing range of motion. Between 1st September 2008 and 31st July 2011, 5 institutions examined early clinical outcomes of a new dual mobility bearing hip system implanted in 485 primary THAs in 452 patients. Patient demographics were 46% female, a mean age of 67 years and a mean BMI of 30. Complications at a minimum of 2 years after surgery included 1 femur fracture, 1 DVT and 4 unrelated deaths. There were no dislocations. For functional outcomes, Harris Hip Scores increased from 41 to 86 (p<0.001), while VAS pain scores decreased from 5.9 to 0.7 (p<0.001). Minimal complications, excellent early clinical outcomes and the absence of early dislocations demonstrate the improved stability of this dual mobility implant system.

Hip resurfacing arthroplasty in severely obese patients.

We conducted a study of outcomes of modern hip resurfacing arthroplasty (HRA) in severely obese patients. Patients who had undergone HRA and been followed for a minimum of 2 years were divided into 2 groups, those with body mass index under 35 (control, 366 hips) and those with body mass index of 35 or above (study, 63 hips). At mean follow-up of 41 months, there was no significant difference between the groups with respect to postoperative Harris Hip Scores, complication rates, and need for revision. Six revision surgeries were required in the control group (98.4% survival), and 2 were required in the study group (96.8% survival). These results suggest that severely obese patients should be considered candidates for HRA.

Prevention of VTE Following total hip and knee arthroplasty in Hemophilia patients.

The often debilitating condition of hemophilic arthropathy is treated with elective total joint arthroplasty. Little has been published addressing the role of thromboembolic prophylaxis in the hemophilic patient population following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Although the American College of Chest Physicians and the American Academy of Orthopaedic Surgeons have set guidelines for thromboembolic prophylaxis in the general population, no such standard of care is in place for hemophilic patients. While the risk of thrombosis in hemophilic patients following THA and TKA is thought to be lower, cases have been reported of pulmonary embolism and deep vein thrombosis (DVT) in hemophilic patients.

The learning curve for adopting hip resurfacing among hip specialists.

UNLABELLED: Patient demand and surgeon interest in hip resurfacing has recently increased, but surgeons in the United States are relatively inexperienced with this procedure. We determined the learning curve associated with hip resurfacing and compared the rate of early complications of the first 650 hip resurfacings between five experienced hip surgeons and a national safety survey database study we previously published, which included 89 surgeons and 537 hip resurfacings. Patient demographics and adverse events were recorded. Specific features on pre- and postoperative radiographs were measured in a blinded fashion by a single observer. There were 13 major complications (2.0%), which is 3.7 times lower than our national safety survey complication rate of 7.4%. All fractures occurred in the first 25 cases performed. The complication rate was higher for the first 25 procedures (5.6%) compared with the second 25 procedures (1.6%). For experienced hip surgeons, the learning curve for avoiding early complications was short, 25 cases or less. The learning curve for achieving the desired component positioning radiographically was much longer, 75 to 100 cases or more. If achieving some ideal component position proves important for long-term function and implant survival, improved instrumentation and surgical techniques would be necessary to shorten the learning curve. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Initial American experience with hip resurfacing following FDA approval.

UNLABELLED: In May 2006, the US Food and Drug Administration approved the first metal-on-metal total hip resurfacing. Surgeons wanting to implant this device were required to undergo formal industry-sponsored training before performing their first case and a technical specialist attended their initial 10 cases. Safety surveys were completed on the first 537 cases performed and included patient age, gender, diagnosis, and occurrence of any unexpected events perioperatively or postoperatively. Intraoperative data were available for all 537 cases (100%), hospital discharge and six-week data were available for 524 cases (97.6%), three-month data were available for 523 cases (97.4%), six-month data were available for 509 cases (94.3%) and one-year data were available for 449 cases (83.6%); the mean followup was 10.4 months. We documented adverse events in 40 (32 major, 8 minor) of the 537 cases including nine nerve injuries and eight dislocations. There were 14 component revisions (3.1%) [corrected] within the first year, including 10 for femoral neck fracture, two for dislocations, and two for acetabular component loosening. Complications were frequently seen among patients older than 55 years of age and in women, emphasizing the importance of appropriate patient selection for the procedure. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.