Marvin E. Steinberg

Classification and management of acetabular abnormalities in total hip arthroplasty

Total hip arthroplasty, for both primary and revision operations, frequently involves bony abnormalities of the acetabulum. No standard nomenclature currently exists for the definition of acetabular deficiencies. A classification system is presented to assist in the preoperative evaluation and to provide a treatment protocol for these defects.

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.

Distinguishing transient osteoporosis from avascular necrosis of the hip.

Transient osteoporosis of the hip is an uncommon, usually self-limited, distinct clinical entity of unknown etiology6633 3639465355 . Classically, it is characterized by disabling pain in the hip without antecedent trauma and by striking radiographic evidence of osteopenia that is isolated to the hip. The syndrome is not widely recognized, perhaps because of its relative infrequency, and radiographs may be unrevealing early in its course. Therefore, transient osteoporosis may be confused with a variety of other conditions6385#{176}’5355 , with avascular necrosis perhaps being the most common misdiagnosis. Although it may be difficult to distinguish between these two conditions in the early stages, it is essential to make the differential diagnosis so that an appropriate treatment plan can be selected. Transient osteoporosis usually resolves spontaneously in six to eight months, after only protected weight-bearing and treatment of the symptoms; avascular necrosis is usually progressive, but early operative intervention may delay the progression or reduce the symptoms in some patients9’#{176}54 . Curtiss and Kincaid’3, in 1959, reported transient demineralization of the hip in three women during the last trimester of pregnancy; this was apparently the first well documented description of what was later termed transient osteoporosis of the hip by Lequesne38, in 1968. Transient osteoporosis has had many names, including transitory demineralization, migratory osteolysis, algodystrophy of the hip, and, most recently, bone-marrow edema syndrome. Unlike avascular necrosis, transient osteoporosis seems to be uncommon, with less than 200 cases having been reported in the literature since its first description53. Typically, patients are initially seen with acute, progressive pain in the hip; an antalgic gait; and a functional disability involving the affected extremity. Approximately one month after the onset of the symptoms, radiographs reveal demineralization of the femoral head and neck without involvement of the joint space. The spontaneous resolution of the symptoms af-

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 nonoperatively 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.

Classification of femoral abnormalities in total hip arthroplasty

Bony abnormalities of the femur can significantly complicate total hip arthroplasty both for the primary and revision operations. No standard nomenclature exists for the description of these femoral abnormalities. A classification system is presented to standardize nomenclature, assist in preoperative planning, and to assist in the reporting of these defects.

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.

Urinary-bladder management after total joint-replacement surgery

We conducted a randomized study of 100 patients to examine the efficacy and risks of two methods of urinary-bladder management after total joint-replacement surgery. Patients who had hip or knee replacement were randomly assigned either to Group I, in which indwelling catheters were placed during the operation and removed the next morning, or Group II, in which urinary retention was treated by intermittent catheterization as needed. After the removal of the indwelling catheter, the patients in Group I had a lower incidence of urinary retention than those in Group II (27 vs. 52 percent; P less than 0.01). Bladder distention (volume above 700 ml) was more common in Group II (45 percent as compared with 7 percent in Group I; P less than 0.01) and was associated with an increased need for subsequent long-term catheterization. There was no significant difference between the groups in the rates of urinary tract infection (11 vs. 15 percent). We could not identify patients at high risk for retention or infection on the basis of preoperative urinary symptoms, previous urinary tract surgery, previous urinary tract infection or urinary retention, high-risk medical conditions, sex, type of anesthesia, or age (in the absence of prophylactic treatment). We conclude that the short-term use of an indwelling catheter after extended surgery, such as joint replacement, reduces the incidence of urinary retention and bladder overdistention, without increasing the rate of urinary tract infection.

Total hip arthroplasty in patients with avascular necrosis of the femoral head : A 2- to 10-year followup

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.

Avascular Necrosis of the Femoral Head

Avascular or aseptic necrosis of bone was probably first described in 1738 by Alexander Munro.68 In 1794 James Russell published a text on necrosis of bone,84 and between 1829 and 1842 Jean Cruveilhier, the noted French anatomist, recorded gross deformation of the femoral head as a late complication of trauma, presumably as a result of vascular damage.26,57,64,67 Kragelund in 1886 and Konig in 1888 published more comprehensive reports on this subject.26,57 Freund, however, is generally credited with the first detailed description of bilateral idiopathic aseptic necrosis of the femoral heads.34,47 The more recent works by Phemister and his associates have become classics on the etiology, pathogenesis, and treatment of this condition.58,79–81

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.