Commentary & Perspective
Commentary & Perspective on
"Periacetabular Osteotomy for the Treatment of Severe Acetabular Dysplasia"
by John C. Clohisy, MD, et al.
Commentary & Perspective by
Michael B. Millis, MD*,
Children's Hospital, Boston, Massachusetts
Clohisy and coauthors report a very favorable experience with the use of the Bernese periacetabular osteotomy in the treatment of sixteen symptomatic, highly dysplastic hips in a group of young patients who were between the ages of thirteen to 31.8 years. All hips were classified as having severe periacetabular dysplasia (at least group IV according to the Severin classification), and eight femoral heads lay within a secondary acetabulum. Selection criteria for the procedure included retention of at least 110° of hip flexion and "sufficient" hip joint congruity on functional flexion-abduction radiographs.
Both the radiographic and clinical improvement was impressive in this very difficult group of patients, with an average improvement to 44.6° in the lateral center-edge angle and to 51° in the anterior center-edge angle. Average improvement in acetabular roof obliquity was also noteworthy, with improvement from a preoperative mean of 37.3° to a near-normal postoperative mean obliquity of 11.4°. Clinically, eleven of the thirteen patients were "satisfied with the result of the surgery." One of the dissatisfied patients had progression of osteoarthritis from grade 1 (according to the Tönnis classification) before the operation to grade 3 at the three-year follow-up, yet she was working full time despite the hip pain. The second dissatisfied patient had recurrent moderate hip pain at three years, despite "minimal secondary osteoarthritis."
No patients in this series had exploratory arthrotomy at the time of periacetabular osteotomy. It is possible that treatable rim or labral pathology may have been present in some of these hips, and perhaps the dissatisfied patients might have had better clinical results if the joints had been explored.
Viewed objectively, the results of treatment in this patient population are compelling. One should not expect clinical or radiographic perfection in such hips following surgery. Reasonable goals in this difficult patient group include improvement in symptoms and gait for some years, improvement in bone stock for the arthroplasty that will inevitably occur in most of them, and avoiding complications that could compromise either function in the short term or subsequent surgery in the long term.
An important question that must have been confronted by the authors when contemplating this procedure for such patients is whether another operative procedure or treatment program could have similar outcomes. Certainly nonoperative treatment would have been futile, given the symptoms already present. No other rotational osteotomy is likely to have done as well, given the satisfying medialization achieved. Chiari osteotomy would not have provided as satisfactory an articulation in these still congruous hips. Arthroplasty in this young patient population with reasonable cartilage space remaining would have been inappropriate and premature.
In 2005, one would expect this group of patients to be evaluated preoperatively with magnetic resonance imaging, such as the dGEMRIC technique of Kim et al.1, and to undergo intraoperative anterior arthrotomy. Improved precision in the preoperative analysis might allow the surgeon to counsel the patient and family regarding the quality of the expected clinical results. Intraoperative arthrotomy potentially could help not only to determine a more accurate prognosis but also to improve the clinical results if problematic rim pathology can be treated.
In summary, Clohisy et al. offer encouraging results in treating an extremely difficult clinical problem. I would emphasize, however, that the most important next step in improving the results of treatment of anatomically severe dysplasia in the mature hip is to improve our methods of early diagnosis and to perform earlier surgical treatment.
*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.
References
1. Kim YJ, Jaramillo D, Millis MB, Gray ML, Burstein D. Assessment of early osteoarthritis in hip dysplasia with delayed gadolinium-enhanced magnetic resonance imaging of cartilage. J Bone Joint Surg Am. 2003;85:1987-92.