Michael J. Grecula

The relationship between the design, position, and articular wear of acetabular components inserted without cement and the development of pelvic osteolysis.

Between 1983 and 1987, an acetabular component with a unique chamfered-cylinder design was inserted without cement in 134 hips. With use of this design, initial stability is achieved through a cylindrical interference fit with the peripheral rim of the acetabulum, without the need for pegs, spikes, or screws. At an average of sixty-four months (range, forty to ninety-six months) after implantation, follow-up data were available for 113 hips (ninety-three patients). No component had been revised for loosening or was radiographically loose. However, the prevalence of balloon-like osteolysis of the pelvis was 17 per cent (nineteen hips). This bone loss was generally not associated with pain or other symptoms. Ten of the nineteen hips that were associated with pelvic osteolysis (including six of the nine that were associated with osteolysis of the ilium) had been reconstructed with use of an acetabular component that had no holes in the shell (that is, the shell was completely solid). This finding indicates that, while elimination of holes through the acetabular shell may have advantages, it will not prevent pelvic osteolysis. The osteolysis of the ilium was associated with a lateral opening of the acetabular component of more than 50 degrees (p < 0.0001). All of the hips in this series had insertion of a porous-ingrowth femoral resurfacing component made of titanium alloy. These components are no longer used. Revision of the femoral side due to osteolysis provided a unique opportunity to inspect directly forty-two clinically well functioning acetabular components. All of the polyethylene liners and acetabular shells were found to be rigidly fixed. Inflammatory tissue at the periphery of the implant-bone interface resulted in circumferential resorption of periacetabular bone despite rigid fixation of the component. This is direct evidence that a process of bone resorption similar to that reported at the cement-bone interface of cemented acetabular components can occur at the implant-bone interface of components inserted without cement. At the reoperation, a communication that had led to the pelvic osteolysis was found through areas of bone resorption at the periphery of the implant-bone interface. These areas were essentially cystic and were filled with a mixture of fluid and friable, yellow-tan tissue. It appeared that the osteolytic process had expanded into the soft cancellous bone and marrow while being contained by the denser cortical shell of the pelvic bones.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of changing indications and techniques on total hip resurfacing.

Recently, improved metal-on-metal bearing technology has led to the reemergence of resurfacing as a reasonable option for total hip arthroplasty. During the course of a prospective multicenter FDA-IDE evaluation of metal-on-metal total hip resurfacings, we modified our indications and emphasized surgical technique where the femoral surface area was small due to femoral cysts and small component size. We assessed the influence of these changes on complication rates in the first cohort of 292 patients and the second of 724, and then compared these outcomes in the second cohort with historical reports of resurfacing. We had a minimum followup of 24 months (mean, 33 months; range, 24-60 months). After changes were made in the indications and technique, the overall complication rate decreased from 13.4% to 2.1% with the femoral neck fracture rate reduced from 7.2% to 0.8%. The outcomes of the second cohort compare with modern-day resurfacing devices and appear superior to historical results. The data suggest patients should be carefully selected and technique optimized to reduce complications. Long-term followup is required to see if these promising results will be maintained.Level of Evidence: Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The efficacy of prophylaxis with low-dose warfarin for prevention of pulmonary embolism following total hip arthroplasty.

The selection of a prophylaxis regimen and its implementation have been influenced considerably by the decreased duration of hospital stays and the pressures of cost containment. The purpose of the present study was to determine the rate of symptomatic pulmonary embolism both before and after discharge, the number of days required to achieve an adequate level of anticoagulation, and the complications associated with the use of low-dose wafarin after total hip arthroplasty. Between 1987 and 1993, 1099 primary and revision total hip arthroplasties were performed in 940 patients who received low-dose warfarin for prophylaxis against thromboembolic disease. The average duration of prophylaxis was fifteen days (range, one to twenty-nine days). The target level of anticoagulation (as indicated by a prothrombin time of fourteen to seventeen seconds) was achieved an average of three days (range, one to sixteen days) after the operation. The level of anticoagulation was lower than the target range at the time of discharge after 257 total hip arthroplasties (23.4 per cent), and the target level was never achieved during the period of hospitalization after fifty-four such procedures (4.9 per cent). Twelve total hip arthroplasties were associated with a symptomatic pulmonary embolism; the over-all prevalence of this complication therefore was 1.1 per cent (95 per cent confidence interval, 0.4 to 1.9 per cent). Four pulmonary emboli were diagnosed before discharge and eight, after discharge. A fatal pulmonary embolism occurred after one procedure (0.1 per cent). Patients who had a history of symptomatic venous thromboembolic disease had a significantly increased risk of symptomatic pulmonary embolism after total hip arthroplasty (p = 0.001, Fisher exact test). A major bleeding episode occurred after thirty-two total hip arthroplasties (2.9 per cent). Patients who had a prothrombin time of more than seventeen seconds had a significantly increased risk of hematoma formation (p = 0.003, chi-square analysis). Prophylaxis with low-dose warfarin is safe and effective for the prevention of pulmonary embolism after total hip arthroplasty.

Precision-fit surface hemiarthroplasty for femoral head osteonecrosis. Long-term results

Cemented Ti-6Al-4V components were used to resurface ten femoral heads in nine young adult patients with osteonecrosis of the femoral head (average age 32 years; range 20 to 51). There were eight hips at Ficat stage III and two at stage IV. Five hips have maintained satisfactory function for an average period of 11.2 years (10 to 12.2) with no radiographic evidence of component loosening or osteolysis; five have been revised after an average period of 7.8 years (3.3 to 10.3) for pain caused by deterioration of the acetabular cartilage. No component required revision for loosening and the specimens retrieved at revision showed no evidence of osteolysis despite burnishing of the titanium bearing surface and the presence of particulate titanium debris in the tissues.

Impact of implant design on femoral head hemiresurfacing arthroplasty

Two consecutive series of cemented femoral hemiresurfacing arthroplasty for patients with Ficat Stage III and early Stage IV osteonecrosis of the femoral head were studied to identify the impact of design on the clinical and radiographic results. Group I (30 patients, 33 hips) components had a cobalt chrome shell with a tapered inner dimension, no stem, and sizes in 2-mm increments. Group II (37 patients, 51 hips) components differed by adding a proportional stem, increased spherical coverage, and sizes in 1-mm increments. The average age for the patients in both groups was 40 years. Fifty percent of the patients in Group I were men; in 43′ of patients osteonecrosis was associated with steroid use and in 21′ of patients it was associated with alcohol use. Thirty-three percent of the patients in Group II were men; in 41′ of patients osteonecrosis was associated with steroid use and in 17′ of patients it was associated with alcohol use. The average followup is 42 months for Group I and 24 months for Group II. Neither group experienced infections, nerve palsies, dislocations, or loosening. In Group I, two patients died of unrelated causes and five patients had reoperations, two for femoral neck fractures, and three for unsatisfactory pain relief. No patients in Group II had femoral neck fractures but three patients had reoperations for unsatisfactory pain relief. The stemmed component in Group II has resulted in an improvement in component position and elimination of femoral neck fractures in this series.

Disparities in utilization of outpatient rehabilitative care following hip fracture hospitalization with respect to race and ethnicity.

OBJECTIVE To compare the prevalence of discharge home to self-care after hip fracture hospitalization among the elderly in 3 racial groups: whites, Hispanics, and blacks. DESIGN Secondary data analysis. SETTING US hospitals. PARTICIPANTS Patients (N=34,203) aged 65 and older with Medicare insurance discharged after hip fracture hospitalization between 2001 and 2005. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE Discharge home to self-care. RESULTS Bivariate analyses showed higher rates of discharge home to self-care among minorities, 16.4% for Hispanics, 8.7% for blacks, and 5.9% for whites. Hispanics had 3-fold higher odds of being discharged home to self-care, and blacks had about 50% higher odds of being discharged home to self-care after adjusting for age, sex, Klabundes comorbidity index, income, year of admission, type of hip fracture, surgical stabilization procedure, and length of hospital stay. CONCLUSIONS The higher rate of discharge home to self-care among minorities underscores the risk of suboptimal outpatient rehabilitative care among minorities with hip fracture.

The impact of rheumatoid arthritis on rehabilitation outcomes after lower extremity arthroplasty.

Background:Medical rehabilitation after lower extremity arthroplasty is an integral part of recovery and a critical step in returning to independent mobility. We hypothesized that rehabilitation may take longer for patients with rheumatoid arthritis (RA) versus osteoarthritis (OA) because joint pain, swelling, and deformities are generally worse among persons with RA. Objectives:To determine the impact of RA on length of rehabilitation stay and rehabilitation functional status gain after arthroplasty. Methods:We conducted a retrospective cohort analysis using a national registry of US medical rehabilitation inpatients admitted after a lower extremity arthroplasty between 1994 and 2001. Sample included 1361 patients with RA and 26,096 patients with OA. The main outcome measure was functional status gain as assessed by the functional independence measure (FIM). Our primary analytic method was linear regression. Covariates were age, gender, race/ethnicity, other comorbidity, admission FIM, and site of arthroplasty. Results:Mean length of stay for patients with RA was 11.3 ± 7.1 days (mean ± standard deviation) versus 10.3 ± 6.5 days for those with OA. Mean weekly gain was 18.6 ± 12.1 for patients with RA versus 20.6 ± 12.0 for those with OA. After adjusting for covariates, RA was associated with longer stay (0.7 day) and lower FIM gain (2.6). Conclusions:RA was associated with longer length of rehabilitation stay and lower FIM gain in patients with lower extremity arthroplasty. Such patients may require additional monitoring to ensure sufficient rehabilitation.

The Impact of Race/Ethnicity on Preoperative Time to Hip Stabilization Procedure after Hip Fracture

Background: We sought to examine the preoperative time for hip stabilization procedure among Hispanics, non-Hispanic blacks (blacks) and non-Hispanic whites (whites). Methods: This was a secondary data analysis using Medicare claims data. Our analysis included 40,321 patients admitted for hip fracture hospitalization from 2001-2005. Our primary analysis was generalized linear modeling, and our dependent variable was preoperative time. Our independent variable was race/ethnicity (Hispanics, blacks versus whites), and covariates were age, gender, income, type of hip fracture and comorbidities. Results: Bivariate analyses showed that both Hispanics and blacks experienced a longer preoperative time (P < 0.01). The average (mean) of days to surgery was 1.2 for whites, 1.6 for blacks and 1.7 for Hispanics. The delayed preoperative time among Hispanics and blacks persisted after adjusting for covariates. Conclusions: The delayed preoperative time among minorities suggests the need to closely monitor care among minorities with hip fracture to determine how to best address their developing needs.

CORR Insights®: Which Classification System Is Most Useful for Classifying Osteonecrosis of the Femoral Head?

Osteonecrosis of the femoral head (ONFH) generally presents in the third to fifth decade of life and is the final pathway of several conditions that eventually result in bone necrosis. The disease progresses in more than half of the patients who have it [9], leading to femoral head collapse and secondary arthritis. However, not all patients experience progression, and a few may experience resolution of the condition in its earlier stages [2]. Many attempts have been made to classify the disease process; there are at least 16 different classification schemes. Of these, only four have been commonly used [8]: Ficat and Arlet [3] (63%), Steinberg [13] (20%), Association Research Circulation Osseous (ARCO) [4] (12%), and system of the Japanese Orthopedic Association developed by the Japanese Investigation Committee (JIC) [14] (5%). Their common classification parameters include patient symptoms, MRI, and radiographic findings including size and location of the lesion, presence of a crescent sign, amount of head depression (collapse), and presence of acetabular changes. In the early stages of ONFH, before collapse, the size and location of the necrotic lesion is considered an indicator and can be predictive of a collapse [12]. Methods to quantitate the lesion size and location include volumetric measurements (Steinberg [13] and ARCO [4]), angular measurements on the AP and lateral radiographic views (Kerboul [5]), index of angular sizes measured on mid-sagittal and mid-coronal slices of the MRI scan (Koo [6]), and location of the lesion in respect to the weight bearing surface (JIC [14]). But each of these methods have their own pitfalls. Volumetric measurements may be too complicated for routine clinical use. Angular measurements can be influenced by lesion shape and distance from the articular surface. Location classification assumes that larger lesions are more lateral, but does not specifically evaluate lesion size. If the femoral head lesion is referenced relative to the acetabular weight bearing surface, this can be influenced by the positioning of the hip during the imaging study. In their current study, Takashima and colleagues [15] conducted a retrospective study and compared the Steinberg (volumetric method), Kerboul (angular method), and Japanese Investigation Committee (JIC) (location) classification systems. They found that all of the classifications worked well in the sense that as the ONFH increased in grade within each classification, the risk of collapse likewise increased.