Core decompression with bone grafting for osteonecrosis of the femoral head.

Although core decompression is one of the more popular procedures for treating avascular necrosis, considerable controversy exists concerning its safety and effectiveness. The current authors review the results of a prospective study of 406 hips in 285 patients treated by one surgeon with core decompression and bone grafting. Patients were followed up for 2 to 14 years. The outcome was determined by the change in the Harris hip score, quantitative radiographic measurements, and need for total hip replacement. These hips were compared with 55 hips in 39 patients treated non-operatively and with historic controls. Five complications occurred after 406 procedures including two fractures that resulted from falls during the first postoperative month. Of the 312 hips in 208 patients with a minimum 2-year followup, 36% of hips (113 hips in 90 patients) required hip replacement at a mean of 29 months: 18 of 65 hips (28%) with Stage I disease; 45 of 133 hips (34%) with Stage II disease; three of 13 hips (23%) with Stage III disease; and 45 of 92 hips (49%) with Stage IV disease. Before femoral head collapse (Stages I and II combined) hip replacement was performed in 10 of 77 hips (14%) with small lesions (A), 33 of 68 hips (48%) with intermediate lesions (B), and 20 of 48 hips (42%) with large lesions (C). Results as determined by changes in Harris hip scores and radiographic progression were similar. Patients who underwent core decompression and bone grafting have a very low complication rate. In patients treated before femoral head collapse, the outcome is significantly better than in patients who received symptomatic treatment. The results are correlated with the stage and the size of the necrotic lesion.

A mobile mammography program in the workplace. Successful program.

United States companies recognize health care costs are rising and the prevention, early detection, and treatment of disease can help with cost control. Onsite mobile mammography can provide a convenient, effective, and time saving service for employees. Establishing a mobile mammography program requires some planning, but is relatively easy to administer and maintain.

The early history of arthroplasty in the United States.

Arthroplasty is defined in the broadest sense as a reconstructive procedure that alters the structure or function of a joint. The first recorded procedures done in the United States in the early nineteenth century and the introduction of modern total joint replacement in the 1970s will be discussed. Although major surgical procedures occasionally were performed in the early 1800s, it was not until the introduction of general anesthesia and antiseptic techniques during the latter half of the nineteenth century that the field of surgery could be developed. Procedures involving the major joints of the upper and lower extremities are described. These procedures include resection and interposition arthroplasties, joint debridement, procedures done to correct complications of hip fractures and developmental dysplasia of the hip, cup arthroplasties, endoprosthetic replacement, hinge arthroplasties, resurfacing procedures, and early total joint replacement.

Does lesion size affect the outcome in avascular necrosis?

The size of the necrotic lesion may be a significant factor in predicting outcome and determining treatment in hips with avascular necrosis. However, to date most reports on the treatment of this condition have not attempted to correlate outcome with lesion size. Seventy-three hips with avascular necrosis were evaluated, 11 in Stage I and 62 in Stage II. All were treated with core decompression and bone grafting. Patients were followed up 2 to 6 years (mean, 39 months). The results were determined by change in Harris hip score, degree of radiographic progression, and the need for total hip replacement. Outcome was correlated with the lesion size, stage, etiology, and other factors. In Stage I, the true three-dimensional size of the lesion was measured with a new technique of quantitative magnetic resonance imaging. In Stage II, measurements were obtained from radiographs using a modular system for quantitative digital analysis. Hips were divided into three groups based on lesion size: Group A, less than 15% of femoral head involvement; Group B, 15% to 30%; and Group C, greater than 30%. There were no significant differences in outcome between Stages I and II and no relationship to etiology or other demographic factors. When correlated with lesion size, radiographs on a 21-point scale showed progression by 1.1, 4.2, and 4.3 points; the Harris hip score showed an improvement of 10.6 and 3.3 points and a loss of 3.6 points; and total hip replacement was required in 7%, 31%, and 33% of Group A, B, and C lesions, respectively. The difference in outcome between small lesions and large or medium lesions was statistically significant, but no significant differences were seen between medium and large lesions. These observations emphasize the importance of lesion size in predicting outcome after core decompression and grafting and possibly after other surgical and nonsurgical methods of managing hips with avascular necrosis. They also encourage the use of methods of evaluation and staging that include a determination of lesion size and stage.

Revision total hip arthroplasty in patients with avascular necrosis.

This retrospective study compared the results of revision total hip arthroplasty (THA) in patients with avascular necrosis to patients with osteoarthritis. Twenty-two revision THAs (34 components) in 19 patients with avascular necrosis were compared with 35 revision THAs (55 components) in 31 patients with osteoarthritis. All of the procedures were performed by a single surgeon between 1981 and 1994, and all patients had a minimum of 2 years of follow-up. At the time of revision surgery, the average age was 54 years for the avascular necrosis patients and 67 years for the osteoarthritis patients (P=.002). Clinical and radiographic follow-up was performed for an average of 7 years (range: 2-12 years). Six (18%) components in the avascular necrosis group and nine (16%) components in the osteoarthritis group required re-revision for aseptic loosening an average of 7 years after the original revision (range: 2-11 years). Statistical analysis demonstrated no significant difference between the two groups in regard to the incidence of failure, time to failure, Harris Hip Score, and radiographic appearance. Contrary to expectations derived from the literature on primary THA, no difference was found between the outcome and survivorship of revision THA in patients with avascular necrosis and patients with osteoarthritis, despite a significant difference in age.

Acetabular involvement in osteonecrosis of the femoral head.

When an arthroplasty is needed to treat osteonecrosis of the femoral head, the use of a component that replaces or resurfaces only the femoral head is often considered as an alternative to total hip replacement if the acetabulum appears radiographically normal. However, the long-term results of the use of endoprostheses have often been poor, secondary in part to progressive degeneration of the acetabular cartilage and to protrusio acetabuli. To help to explain these observations, we examined the acetabular cartilage in forty-one hips in which a primary total hip replacement had been performed because of osteonecrosis of the femoral head in association with a radiographically normal acetabulum. The cartilage in the superior, weight-bearing region of the acetabulum was grossly abnormal in forty of the forty-one hips and it was histologically abnormal in all thirty-three hips that were so evaluated. In all but one hip, gross degeneration of the cartilage was apparent, involving less than 20 percent of the acetabulum; the degeneration was graded as mild (superficial fibrillation and slight irregularity of the surface) in sixteen hips, moderate (moderate fibrillation, alteration in color and consistency, and thinning of cartilage without complete erosion to bone) in twenty hips, and severe (marked fibrillation, alteration in color and consistency, and marked thinning of cartilage with areas of complete erosion to bone) in four hips. These observations emphasize the fact that radiographs cannot demonstrate early degeneration of cartilage and that, by the time that an arthroplasty is needed, degenerative changes are already present in the acetabular cartilage of a high percentage of hips with osteonecrosis, even when radiographs of the acetabulum show no abnormalities. These findings should be kept in mind when a decision is being made regarding which type of arthroplasty should be done in a patient who has osteonecrosis of the femoral head and regarding when to do the procedure.

Carry it on the bad side!

Patients with diseased hips often must carry objects while walking, yet they are rarely instructed which hand to use because little has been published on the subject. We sought to evaluate the situation mathematically by determining the hip forces that result when a load is carried in the ipsilateral versus the contralateral hand. Using a free-body diagram of single-leg supported stance, we found that when a load was carried in the contralateral hand, the resultant forces on the hip were increased considerably. Conversely, when the weight was carried in the ipsilateral hand, the forces were actually lower than when no weight was carried at all. Thus, carrying a weight on the opposite side resulted in hip forces that were substantially greater than when the weight was carried on the same side.

Drain entrapment and titanium to ceramic head deposition: two unique complications following closed reduction of a dislocated total hip arthroplasty.

Postoperative dislocation remains one of the most frequent complications following total hip replacement. In this report, a case is presented that illustrates two potential concerns with postoperative dislocation and subsequent closed reduction. The first complication presented in this report is entrapment of a closed drainage system tube in the joint space following closed reduction. The second complication, transfer of metallic debris to a ceramic femoral head from contact with an acetabular shell during closed reduction, was documented by analysis of a femoral head using scanning electron microscopy and energy dispersive x-ray spectrometry. This report emphasizes the need for the surgeon to express caution when relocating a dislocated hip, particularly when a closed drainage system is used postoperatively.

Absenteeism among employees who participated in a workplace influenza immunization program.

To assess the effectiveness of a free workplace immunization program at 3M's St. Paul, Minnesota locations, we examined the difference in sick leave hours taken from November 15, 1996, through March 15, 1997, for employees who had and did not have an influenza vaccination prior to the previous year's four-month influenza season (November 15, 1995-March 15, 1996). Among the 2,622 employees who self-reported that they were not immunized in the previous year, there were, on average, 1.2 fewer hours of sick leave taken during the 1996-1997 influenza season than the comparable time period one year earlier (P < 0.05), although the exact reason for the absenteeism was not determined. In particular, we observed that female employees younger than 50 years of age with two or more children took 3.1 hours less sick leave in the year they were immunized, compared with the preceding year (P < 0.0001). Among the 895 subjects who were immunized in both years, employees took 0.7 hours more sick leave during the 1996-1997 influenza season than the previous year (P = 0.46). Based on our findings, consideration should be given to workplace immunization programs. However, we urge caution in applying a "one-size fits all" approach to any cost-savings analysis from a company-sponsored immunization program because the workplace is not a homogeneous [corrected] environment, with regard to employees' age, gender, medical history, and home environment. All of these factors may directly or indirectly contribute to the risk of acquiring influenza and any of its complications.

Total hip arthroplasty in patients with avascular necrosis of the femoral head: a 2- to 10-year follow-up.

One hundred twenty-three total hip arthroplasties were performed in 85 patients with osteonecrosis of the femoral head. There were 51 males and 34 females with an average age of 45 years. The average followup time was 4.6 years with a range of 2 to 10 years. All femoral stems and 71 sockets were fixed with acrylic cement. Fifty-two of the sockets used were placed without cement. The average Harris hip score improved from 45 points preoperatively to 92 points at the time of last followup. Of the 246 components used, 6 acetabular and 4 femoral prostheses in 7 patients have been revised (4%). Two components (0.8%) were revised for infection, 2 (0.8%) for repeated dislocation, and 6 (2.5%) for aseptic loosening. There is current radiographic loosening in 3 acetabular and 2 femoral components (2%). None of the noncemented acetabular components was either radiographically loose or revised. Within the subset of the 36 patients (52 hips) with a minimum 5-year followup (average, 6.6 years), 5 components (5%) were revised and 4 (4%) components are radiographically loose. The overall revision rate for cemented and hybrid hips at 2 to 10 years followup was 4%. The revision rate for hybrid hips alone was 2.5% in the entire series and 2% for hips with a minimum followup of 5 years. These results seem significantly better than previously reported. Using modern cement techniques and components, total hip arthroplasty can give excellent results in the young patient with avascular necrosis and may be the treatment of choice when reconstructive surgery is required.

Magnetic resonance venography versus contrast venography to diagnose thrombosis after joint surgery.

Magnetic resonance venography is a recently developed, noninvasive means of visualizing the proximal veins of the lower extremity and pelvis. Magnetic resonance venography is compared with standard contrast venography in the diagnosis of proximal deep vein thrombosis after total joint arthroplasty. Two hundred seven extremities were evaluated in a blinded study 5 to 7 days after surgery. Standard contrast venography identified 11 proximal deep vein thromboses. Initial interpretations of the magnetic resonance venographies by staff radiologists identified 5 of the proximal vein thromboses (sensitivity 45%). Two patients with negative standard contrast venographies were identified as positive (specificity 99%). A retrospective review of all magnetic resonance venographies by a dedicated magnetic resonance angiographer identified 10 of 11 deep vein thromboses seen on standard contrast venography (sensitivity 91%). Both false negatives were identified as positives. Standard contrast venography remains the gold standard for identifying proximal vein thromboses. Emerging magnetic resonance imaging techniques have created a potential alternative modality by which to identify deep vein thrombosis. The present study suggests that standard contrast venography continues to be the most accurate modality currently available. Although magnetic resonance venography seems to be accurate, its interpretation requires experience. As costs diminish and experience increases, magnetic resonance venography will have increased importance in the clinical recognition of deep vein thrombosis.

Deep venous thrombosis after total joint arthroplasty. The role of compression ultrasonography and the importance of the experience of the technician.

We evaluated the influence of the expertise of the technician on the accuracy of compression ultrasonography as a screening test to detect postoperative deep venous thrombosis in patients who had had primary or revision arthroplasty of the hip or the knee. The study was performed in two phases on two groups of patients who were evaluated with both compression ultrasonography and conventional venography. All of the patients received prophylaxis for deep venous thrombosis. In the first phase of the study, adequate venograms and ultrasonograms were made for 126 extremities (121 patients). Venography demonstrated seven thrombi in the proximal veins. Only three ultrasonograms were considered positive. Ultrasonography had a sensitivity of 0 per cent because none of the seven proximal thrombi identified with venography were detected with ultrasonography. Three ultrasonograms were false-positive (that is, the ultrasonogram was positive and the venogram was negative), so the specificity was 97 per cent. The accuracy of compression ultrasonography was 92 per cent. Both tests were performed on a second group of eight-seven extremities (eighty-four patients). Proximal clots were detected with venography in five extremities. The ultrasonogram was positive for seven extremities, including the five in which a clot had been identified with venography. There were no false-negative and two false-positive results. In this phase of the study, ultrasonography had a sensitivity of 100 per cent, a specificity of 98 per cent, and an accuracy of 98 per cent. The only difference that was identified between the two groups of patients was the experience of the ultrasonography technician. It appears that the reliability of compression ultrasonography is directly dependent on the experience of the technician.

Effects of etidronate and oophorectomy on the zeta potential of rat bone.

Recent clinical trials in osteoporotic patients show that cyclical etidronate therapy can increase vertebral bone mass and reduce the incidence of vertebral fractures. Stress generated potentials, which are theorized to participate in a negative feedback arrangement regulating bone and which are electrokinetic in origin, can be characterized in vitro by the zeta potential, a measure of electrical surface charge. Thus, the possible effects of etidronate and oophorectomy on the zeta potential of bone were investigated with respect to bone remodeling, pathophysiology, and osteoporosis. Thirty-two oophorectomized and 48 sham oophorectomized rats received subcutaneous etidronate or saline. The zeta potential magnitude of the control group (sham oophorectomized, vehicle only) increased 23.6% from age 6 to 10 months, a period of bone growth. After 6 weeks of etidronate treatment, which decreased bone turnover, the zeta potential magnitude was decreased 14.9% (0.59 mV) compared with that of controls. Decreased zeta potential magnitudes with etidronate treatment also were observed in sham oophorectomized groups at 16 weeks and in oophorectomized groups at 6 and 16 weeks, but the differences were not statistically significant. A large bolus of etidronate had no effect. The zeta potential of bone is a dynamic quantity that may correlate with bone growth or bone turnover. Whether it exerts a causative effect or is a marker remains unknown.

Aspirin and warfarin for thromboembolic disease after total joint arthroplasty.

This study compares the benefits of aspirin and warfarin prophylactic agents for patients with thromboembolic disease after total joint arthroplasty. It is a prospective randomized study of 388 patients having total hip or total knee surgery. All consecutive patients having total hip or total knee surgery were entered into this study and evaluated with preoperative and postoperative ventilation perfusion scans and a postoperative venogram. The aspirin and warfarin treatment groups were compared by size and location of venographically revealed clots and changes in ventilation perfusion scans. The results showed that there was no difference in the size or location of deep venous thrombosis in the aspirin or warfarin treatment groups. The venogram was negative in 44.5% of patients; 28.8% had small ++calf clots, 16% had large calf clots, 3.9% had popliteal clots, and 6.7% had femoral clots. Patients with total knee replacement had a 2.6 times greater incidence of calf deep venous thrombosis than patients with total hip replacement. There was no difference between the aspirin and warfarin groups in the incidence of changes in ventilation perfusion scans (18.9%). There was no difference between the 2 groups in bleeding complications. The results suggest that aspirin and warfarin are equivalent in prophylaxis against thromboembolic disease, as determined by prevention of venographic changes or changes in ventilation perfusion scans.

Core decompression of the femoral head for avascular necrosis: indications and results.

OBJECTIVE: To evaluate the effectiveness and safety of core decompression in the treatment of avascular necrosis (AVN) of the femoral head. DESIGN: A case study. SETTING: The department of orthopedic surgery in a major university hospital. PATIENTS: All patients with AVN of the femoral head, stages I to IVA, were included regardless of the cause of the necrosis. Three hundred hips were available for analysis. The follow-up ranged from 2 to 12 years. INTERVENTION: Core decompression of the femoral head was performed with an 8-mm Michele trephine inserted from just below the greater trochanter into the centre of the necrotic lesion to within 5 mm of the articular surface. Two more trephine tracts were made with a 5-mm or 6-mm trephine. The normal portion of cancellous bone recovered from the intertrochanteric region was thinned with a rongeur and was placed loosely into the central decompression channel at the end of the procedure to serve as a graft. MAIN OUTCOME MEASURES: Anteroposterior and lateral radiographs, taken immediately before surgery and at the final follow-up, clinical hip evaluation according to the Harris scoring system, and the need for total hip replacement. RESULTS: One patient sustained a subcapital fracture 1 month after surgery due to a fall. There was one case of nonfatal pulmonary embolism, one case of pneumonia and one case of thrombophlebitis of the thigh. Forty-six percent of operatively managed hips showed no radiographic progression of disease compared with only 19% of nonoperatively managed hips. Thirty-five percent of the operatively managed hips required total hip replacement compared with 77% of nonoperatively managed hips. The results in hips with early (stages I and II) AVN were only slightly better than those of hips with advanced (stages III and IVA) disease. However, the results in hips with small areas of necrosis in both stages I and II were much better than those with larger lesions; only 7% of the former group required total hip replacement after decompression and cancellous bone grafting. CONCLUSIONS: Core decompression with cancellous bone grafting is a safe and effective procedure for the treatment of early AVN of the femoral head. Results with this form of treatment are considerably better than those obtained in patients treated nonoperatively. Decompression with or without bone grafting is the author's treatment of choice for patients with early AVN of the femoral head.

A quantitative system for staging avascular necrosis.

Much of the current confusion and contradiction on the treatment of avascular necrosis of the femoral head is caused by the lack of an agreed efficient, quantitative system for evaluation and staging. We have used a new system to evaluate over 1000 hips with avascular necrosis during a period of 12 years; it has proved to be very valuable. The system is based on the sequence of pathological events known to take place. It allows accurate quantification in both early and later stages, does not use older, invasive diagnostic procedures, and incorporates the newer techniques of bone scanning and MRI. Clinical records of pain and reduced function are not a specific part of the system, although they help to determine treatment and outcome. Hips are first placed into one of seven stages from 0 to VI, based upon the type of radiological change. The extent of involvement is then measured. This allows more accurate evaluation of progression or resolution and better comparison of different methods of management. The system also helps to provide a prognosis and to decide on the best available method of treatment.

Significance of deep venous thrombosis in the lower extremity after total joint arthroplasty.

Thromboembolic disease continues to pose a significant risk to patients undergoing total joint arthroplasty, but the clinical significance of a deep venous thrombosis (DVT) in the postoperative period remains controversial. This report reviews the outcome of 920 patients undergoing prospective obtained venograms after total hip and total knee surgery. Six hundred two patients also obtained postoperative ventilation perfusion scans (V/Q). All patients received one of the following forms of prophylaxis: aspirin (79%), warfarin (16%), or low-molecular-weight heparin (5%). The results show that 39% were without any clot, 36% had small calf thrombi, 19% had large calf thrombi, 2.5% had popliteal thrombi, and 3.8% had femoral thrombi. Calf thrombi occurred almost 2.5 times more frequently after total knee arthroplasty than total hip arthroplasty (67% versus 27%), yet the incidence of pulmonary embolism (PE) is the same in both groups. Intermediate or high probability V/Q results occurred in 103 patients (15%). There was a positive association between the size of a clot and the likelihood of an intermediate- or high-probability V/Q scan. Thromboembolic events resulted in five symptomatic PE (0.5%) and two deaths (0.2%), one in the hospital on warfarin, and one as an outpatient on aspirin. From these data, the authors conclude that calf thrombi by themselves do not place a patient at risk and are not accurate markers of a patient being at risk. Larger clots have a greater likelihood to embolize, but the size of the clot that is clinically significant is undetermined. A significant chance of a PE after discharge from the hospital warrants some form of continuing prophylaxis in outpatients.