The adult patient with dysplasia often presents with symptoms long before joint replacement can be considered as a lifetime solution1,2. Fortunately, surgical realignment of the congruous dysplastic acetabulum can improve symptoms for years in a majority of appropriately selected patients, even in those with some degree of preoperative arthrosis3-5. Pelvic reorientation osteotomy was first devised by Salter6,7 in the 1950s, before the advent of total hip replacement. Salter's innominate osteotomy was novel in concept but limited in both amount and direction of correction. The subsequent five decades have seen major advances in the surgical techniques of acetabular realignment, beginning in the 1960s with the independent innovation of rotational acetabular osteotomy by Ninomiya and Tagawa in Japan8 and Wagner9,10 in Germany. In 1988, Ganz et al.11 described a new periacetabular osteotomy that offered improved fixation, easier medialization of the acetabular fragment, and the possibility of abductor-sparing surgical approaches. Salter et al.3 and subsequent authors12-14 observed that achievement and/or maintenance of femoroacetabular congruity is essential to good long-term outcome following acetabular realignment.
The real and perceived technical challenges represented by acetabular realignment osteotomies may be a factor that limits their application. Therefore, reports of the learning curve associated with periacetabular osteotomy are pertinent15,16. Peters et al. offer an honest report of their first eighty-three periacetabular osteotomies, which were performed between 1997 and 2003. They have carefully documented the education and the preparation undertaken by the senior surgeon before he began performing the procedure.
Eleven of the twelve reported complications occurred within the time span of the first thirty procedures. Only one complication, a transient femoral nerve palsy, occurred within the time span of the last fifty-three operations. A high proportion of the patients achieved greatly improved function at the time of follow-up, as reflected by improvement in the mean Harris Hip Score from 54 preoperatively to 87 at the time of follow-up. Failure occurred in four hips, three of which were converted to a total hip replacement because of progressive arthrosis and one of which underwent revision periacetabular osteotomy as treatment for femoroacetabular incongruity. All four of these failed hips were in the first group of thirty hips that underwent the procedure, perhaps again reflecting a learning curve in terms of both operative technique and/or patient selection.
Peters et al. clearly and frankly describe the evolution of their surgical treatment program for the skeletally mature patient with symptomatic acetabular dysplasia. They describe their current techniques of preoperative evaluation (including complex imaging) and intraoperative techniques (including attention to intraarticular pathology, assessment of acetabular version, and potential femoroacetabular impingement), which represent the state of the art in this field as it is practiced in North America in 2006. Though Dr. Peters did not, as he frankly admits, train directly in Berne, he is clearly a worthy disciple of the Bernese principles of joint preservation procedures in treating acetabular dysplasia. His paper offers a useful roadmap for the surgeon wishing to undertake the practice of joint-preserving surgery for hip dysplasia, and it may serve to diminish the learning curve for future surgeons.
In a most interesting article, Yasunaga et al. report their extremely positive experience in the use of rotational acetabular osteotomy in forty-three hips at an advanced stage of osteoarthritis, analogous to Tönnis grade II17. The mean age of the patients at the time of surgery was 43.8 years, and the mean duration of follow-up for these forty-three hips was 8.5 years.
Clinical results as assessed with use of the Merle d'Aubigné score improved from a mean of 13.3 preoperatively to 15.4 points at the time of follow-up, with a mean improvement of 2.4 points in the pain score, a slight decrease in mean mobility of 0.1 point, and no change in the score for walking ability. Postoperatively, the clinical score was <14 points in nine hips, with five of these hips having end-stage arthritis radiographically and two of them having been converted to total hip arthroplasty.
Radiographic results showed disappearance of preexisting cysts in six hips, appearance of new cysts in four previously noncystic hips at follow-up, and no change in the cystic appearance in the rest of the twenty-three cystic hips.
Radiographic factors associated with radiographic signs of progression after revision acetabular osteotomy included fair rather than good preoperative congruence, preoperative joint space of <2.2 mm, and postoperative joint space of <2.5 mm.
The Kaplan-Meier survivorship analysis predicted a ten-year survival rate of 72.2%.
This report by Yasunaga et al. is remarkable and important for several reasons. First, in many parts of the world, patients with this degree of arthrosis, even with demonstrated congruity in abduction, have only infrequently been considered as candidates for joint-preserving acetabular redirection osteotomy. Second, this is a report of a reasonably large number of patients, followed for a reasonably long period of time. The results are quite good at three and ten years following revision acetabular osteotomy, with only two hips having been converted to arthroplasty.
Should surgeons in other parts of the world attempt to apply this positive experience of Yasunaga et al. to their own practices, they should be aware that differences in patient population, surgical technique, and postoperative treatment may lead to dramatically different results. For example, it may be more important to correct intraarticular pathology in the non-Japanese dysplastic hip. The relatively prolonged and gradual resumption of weight-bearing, which is not usually practiced in North American and European centers, may or may not be critically important in this particular patient group with established arthrosis.
In summary, Yasunaga et al. have set a high standard for joint-preserving surgery in this group of patients with dysplasia and congruous moderate arthrosis. While many surgeons may prefer to manage these patients with total hip arthroplasty, joint replacement clearly should not be the only surgical option considered.
*The author did not receive grants or outside funding in support of his research for 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.
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