Commentary & Perspective by
Marvin E. Steinberg, MD*,
Department of Orthopaedic Surgery, The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
Without specific treatment, >70% of hips with osteonecrosis will eventually collapse and require arthroplasty1. Several techniques are available for the treatment of early-stage osteonecrosis of the hip. Most of these techniques will produce better results than symptomatic management alone, but no technique is completely satisfactory. Core decompression is the method that is most frequently used, but opinions differ as to its effectiveness. Some investigators have reported good results with more invasive techniques, such as osteotomy and various grafting procedures, but these are technically more difficult than core decompression and are associated with a substantial prevalence of complications. It is therefore essential that we continue to seek more effective methods to treat osteonecrosis of the femoral head.
Gangji et al. have reported their experience with direct implantation of autologous bone-marrow cells into the femoral head as a treatment for stage-I or stage-II osteonecrosis. They performed a limited core decompression on eighteen femoral heads, with use of a 3-mm trephine. Autologous bone marrow was implanted into ten, and eight were used as controls. At twenty-four months, the authors found that hips treated with marrow implantation had a better outcome than controls, as determined by clinical improvement, lack of radiographic progression, and need for total hip replacement. The authors concluded that this technique appeared to be effective for early stages of osteonecrosis, but acknowledged that, because of the small number of patients and the short duration of follow-up, additional study is needed to confirm their results. This note of caution is certainly appropriate.
Perhaps the most important indicator of success in the treatment of osteonecrosis of the femoral head is the ability of a technique to eliminate or delay the need for additional surgery, in particular arthroplasty. In this study, two of eight controls and zero of ten treated hips underwent a total hip replacement. This does not represent a significant difference, perhaps because of the small number of hips involved. The authors found that the necrotic lesions occupied a mean of 15.6% and 16.7% of the entire femoral head in treated and control hips, respectively. This is surprising since, in most other series, the lesions were found to be considerably larger and the variation in size was noted to be greater2,3. If the measurements of Gangji et al. are in fact correct, it would indicate that they were dealing with a series of hips that had small areas of necrosis and thus a much better prognosis than that of hips with moderate-to-large lesions2,3. The authors reported a small decrease (5.5%) in lesion size in treated hips and a small increase (3.9%) in lesion size in control hips. However, most other investigators who made use of similar measurement techniques have not found them sensitive enough for accurate detection of such small changes in lesion size3.
The authors refer to their operative procedure as a core decompression, although they used only a single, small 3-mm track. Most other investigators have used one or more 8-mm to 10-mm tracks or several small tracks as a way of reaching a greater portion of the necrotic lesion. Caution is therefore advised when considering the comparability of these techniques.
In an earlier publication cited by the authors, Hernigou and Beaujean2 reported their results after using a very similar method to treat 658 hips, 189 of which had a five to ten-year duration of follow-up. Hip replacement was required in only 3% of stage-I hips and 8% of stage-II hips. Clinical and radiographic results were similar. Hips with small lesions (<25% of femoral-head involvement) had a significantly better outcome than hips with larger lesions (p < 0.05). Better results were also seen in hips that received marrow containing a higher number of nucleated progenitor cells. Unfortunately, their series included no controls; however, their methods yielded results that were significantly better than those reported by other authors for hips that were treated with core decompression as well as for untreated hips1,3.
The osteogenic effects of bone marrow are well established. Bone marrow and marrow concentrates can enhance the healing of fresh fractures and delayed unions4. It is of interest that a single injection of marrow cells into an area of necrotic bone might result in a process of new bone formation and repair that seldom occurs spontaneously. Theoretically, the osteogenic precursor cells from the marrow may serve to repopulate segments of necrotic bone with viable, active cells.
The present study seems to support the conclusions of Hernigou and Beaujean2 and gives us the advantage of including a control group for comparison. Taken together, these two publications should be given serious consideration. They suggest that this technique should be evaluated by other investigators. If these findings can be confirmed, this approach may well represent an important advance in the treatment of early-stage osteonecrosis of the hip.
*The author did not receive grants or outside funding in support of his research or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.
1. Mont MA, Carbone JJ, Fairbank AC. Core decompression versus nonoperative
management for osteonecrosis of the hip. Clin Orthop. 1996;324:169-78.
2. Hernigou P, Beaujean F. Treatment of osteonecrosis with autologous bone marrow grafting. Clin Orthop. 2002;405:14-23.
3. Steinberg ME, Bands RE, Parry S, Hoffman E, Chan T, Hartman KM. Does lesion size affect the outcome in avascular necrosis? Clin Orthop. 1999;367:262-71.
4. Connolly J, Guse R, Lippiello L, Dehne R. Development of an osteogenic bone-marrow preparation. J Bone Joint Surg Am. 1989;71:684-91.