Introduction

The different types of treatment for osteonecrosis of the femoral head have not led to a consensus about which treatment is best for the different stages. Particularly in the later stages of osteonecrosis, the disease still progresses to destruction of the femoral dome. The purpose of our study was to check the outcome of bone impaction grafting used for the head-preserving treatment of severe femoral head osteonecrosis. In order to preserve the femoral head, the sphericity and mechanical properties of the femoral dome must be contained and further collapse prevented.

Introduction: Since 2004, in addition to the original curved varus osteotomy for osteonecrosis of the femoral head, we have intentionally performed anterior or posterior rotation without incising the articular capsule to obtain a more extensive viable area in the loaded portion. We investigated the extent of viable area on the loaded portion after this modified operation.

Materials and Methods: Subjects included 11 patients (13 joints: anterior, 12 joints; posterior, 1 joint) who underwent a modified curved varus osteotomy and anterior or posterior rotation. We investigated the percent of viable area in the preoperative vs. the postoperative weighted portion. In addition, we measured the extent of viable area in the loaded portion when the extent of curved varus osteotomy without rotation was performed based on a schematic drawing.

Results: In this study, the combination of transtrochanteric curved varus osteotomy and anterior or posterior rotation significantly increased the percent viable area from 66% to 85%.

Discussion: The extent of postoperative viable area on the loaded portion might have been increased more than in the original procedure.

Introduction: We evaluated antero-posterior instability of the hip with osteonecrosis immediately after anterior rotational osteotomy using Dynamic CT and investigated the relationship between the instability and the developing marginal osteophyte of the femoral head postoperatively.

Materials and Methods Twenty-three hips in 21 patients with non-traumatic osteonecrosis undergoing anterior rotational osteotomy were studied. There were 19 men and 2 women with a mean age of 39 years at operation. All patients were followed up for more than 2 years (mean: 4). The etiologic factors were steroid administration in 10, alcoholic abuse in 12, and both in 1. According to the staging system by the Japanese Ministry of Health, Labor, and Welfare, there were 11 hips in stage 3a (collapse less than 3 mm), 9 in 3b (collapse 3 mm or greater), and 3 in stage 4. Dynamic CT, taken in both neutral and 45 degrees flexion positions, studied the antero-posterior shift of the femoral head. In addition, we analyzed marginal osteophytes with more than 2 mm in size on follow-up A-P radiographs.

Results: Seven hips (30%) with 5 hips in stage 3b and 2 hips in stage 4 showed instability. Marginal osteophytes were shown in 8 hips including all of 7 hips with the instability. However, these hips had no joint narrowing.

Conclusions: From these results, hip instability immediately after anterior rotational osteotomy occurs in cases with an extensive necrotic lesion and marked collapse preoperatively. Developing marginal osteophytes may prevent the instability.

Introduction: In cases of small and middle size osteonecrosis on conventional antero-posterior (AP) radiographs, we studied the extent of the lesion on AP radiographs at the 45 degrees flexion position for lesions of the anterior area of the femoral head.

Materials and Methods: Classification of Japanese organizing committee was applied for the extent of the lesion on joint surface. Type A lesions occupy the medial one-third or less; Type B, the medial two-thirds or less; Type C-1 occupies more than the medial two-thirds; and Type C-2 extends laterally to the acetabular edge at the neutral position on conventional AP radiographs. Thirty-three hips (25 patients) with small or middle size lesions (Type A;11, Type B;22) were studied. On AP radiographs taken at the 45 degrees flexion position, the extent of the lesion was studied in 33 hips.

Results: Seven of 11 hips of Type A on neutral position showed Type A lesions. For the remaining 4 hips, 2 were Type B, 2 were on Type C-1 at 45 degrees flexion position. For 22 hips with Type B on neutral position, 6 were Type B, 12 were Type C-1, 4 were Type C-2 found at the 45 degrees flexion position.

Discussion: AP radiographs at the 45 degrees flexion position revealed more extensive necrotic area in cases of small and middle size lesions comparing with the neutral position. This finding may be related to progression of the disease.

Introduction: We investigated the necrotic area and its shrinkage on stage 1 femoral head necrosis with band pattern low intensity on MRI.

Materials and Methods: Eleven femoral heads (6 patients) with a history of steroid treatment were studied. In heads, band pattern was detected by MRI. The mean age was 40 years.

The location of the lesion shown by the band pattern low intensity was determined by Japanese investigation committee as follows. Type A lesion occupies the medial one-third or less; Type B occupies the medial two-thirds or less; Type C-1 occupies more than the medial two-thirds; and Type C-2 extends laterally to the acetabular edge at the neutral position. Types were observed on initial and final MRIs. The mean follow up was 4 years and 3 months. For the repair patterns, the direction was observed in the anterior and posterior slices of MRIs.

Results: Initial MRIs showed types were Types A, B, C-1, and C-2 in 3, 3, 3, and 2 femoral heads, respectively. At the final observation, no band pattern was noted on the weight-bearing surface in 3 Type-A femoral heads. The femoral head surface was repaired, and the lesion was present only in the non-weight-bearing region. In all of the 3 Type-B femoral heads and 5 Type-C1 and -C-2 femoral heads, the lesion shrank to Type A. The articular surface was covered with normal intensity area from the posterior direction in all femoral heads

Discussion: We believe that the repair occurred during the disease process in stage 1 necrosis.

Introduction: Posterior rotational osteotomy has been used in young patients to treat apparent collapse and extensive osteonecrosis of the femoral head. We have reviewed a series of our patients with greater than 3 year follow-up.

Materials and Methods: Forty-three hips in 32 young patients with non-traumatic femoral head osteonecrosis were treated by posterior rotational osteotomy. All heads were apparently collapsed (Greater than 3mm), and 12 hips showed joint narrowing. Extensive lesions were noted on measurements of the area below the acetabular roof on preoperative AP radiographs. The age of the patients at the time of surgery ranged from 15 to 48 years with a mean of 34 years. There were 13 women and 19 men. Nineteen patients received steroid administration, 9 had alcoholic abuse, 6 had no apparent risk factor. Posterior rotational angle was 60–150 degrees with a mean of 124 degrees. We reviewed radiographically at 3 to 17 years follow-up (mean; 7.6 years).

Results: Re-collapse were prevented in 39 hips (91%) on final follow-up AP radiographs. Progressive joint narrowing was found in 6 hips (14%). Of the remodeling, we observed a collapsed area on the medial portion of 19 hips after posterior rotation. Re-spherical contour was noted on 18 hips. In 12 hips with joint narrowing preoperatively, atrophy of acetabular subchondral bone was seen on 12 hips 6 months postoperatively. A newly formed acetabular bony roof was noted in 11 hips at 2 years postoperatively.

Discussion: These results suggest that this operation is effective for young patients with advanced stage osteonecrosis.

Introduction: The results of noncemented press-fit bipolar hip endoprostheses were reviewed in patients with osteonecrosis of the femoral head.

Materials and Methods: Twenty-nine hips in 24 patients with osteonecrosis of the femoral head were studied. The average follow-up period was 12 years and 5 months (range from 9 years 2 months to 17 years 11 months). All hips were classified as stage 3 or 4 (osteonecrosis) before surgery using the classification method of the Japanese Investigation Committee. Acetabular reaming was performed in 5 hips with stage 4 osteonecrosis.

Results: Four prostheses have been revised to a total hip arthroplasty at the time of follow-up examination. The average clinical hip score of Japanese Orthopaedic Association was 88.9 (98–82) with 23 hips rated excellent and good, and 6 hips rated fair. Radiologically, stem subsidence more than 5 mm occurred in 5 hips and stem loosening occurred in 6 hips (21%). Five hips with stage 4 osteonecrosis (3 hips received acetabular reaming, 2 hips in elderly patients with osteoporosis) developed outer head migration more than 4 mm in both superior and axial direction. Osteolytic lesions, seen on 11 hips in the femur and 3 hips in the acetabulum, appeared at an average of 4.2 years postoperatively.

Conclusion: These results suggest that cementless pressfit bipolar endoprosthesis for osteonecrosis demonstrated a high incidence of acetabular protrusio and osteolysis. Cementless THA with a porous coating stem should be recommended for treatment of osteonecrosis of the femoral head.

Introduction: Even in extensive osteonecrosis of the femoral head, a head-preserving method is preferable in younger patients. This study presents the results of bone impaction grafting for osteonecrosis of the femoral head.

Materials and Methods: After a core biopsy and removal of the osteonecrotic area, impacted morsellized bone allografts were used to fill the femoral head to regain sphericity, and to prevent collapse. This prospective, single-surgeon study included 28 consecutive hips in 27 patients with extensive osteonecrotic lesions (ARCO classification Stage 2 (11 hips), Stage 3 (14 hips), and Stage 4 (three hips). Fourteen hips had preoperative collapse. The mean age of the patients was 33 years (range, 15–55 years).

Results: At a mean follow-up of 42 months (range, 24–119 months), eight hips (29%) had been converted to a total hip arthroplasty. Of the 20 reconstructions that were in situ, 18 were clinically successful (90%) and 70% were radiologically successful. Patients who were younger than 30 years at surgery had a significantly better radiologic outcome, even when compared to heads with higher stages of osteonecrosis. Patients with preoperative collapse or a continuous use of corticosteroids had disappointing results.

Discussion: This method is attractive as a salvage procedure for osteonecrosis of the femoral head. It is relatively simple and quick to perform, and it does not intervene with an eventual future hip arthroplasty.