Joseph P. Bogdan, M.D.,
William G. Mackenzie, M.D., S. Jay Kumar, M.D.
Alfred I. duPont Institute
1600 Rockland Road
Wilmington, Delaware 19803
INTRODUCTION: The hereditary motor and sensory neuropathy (Charcot-Marie-Tooth) is characterized by diminished reflexes, symmetric distal weakness, and atrophy more marked in the lower extremities. The orthopaedic manifestations of type I (hypertrophic form) and type II (neuronal form) include drop foot gait, pes cavovarus, scoliosis, and patellar dislocations. In 1985, Kumar et al. reported an association between hip dysplasia and CMT. The study by Kumar et al. suggests the initial short term results of operative treatment to be satisfactory.
PURPOSE:
MATERIALS AND METHODS: This study was a retrospective review of charts, radiographs, and follow-up questionnaire assessing the long term results of operative management of hip dysplasia in CMT. Nine patients were treated operatively (1977 - 1996). The group included 7 females and 2 males; 8 type I and 1 type II. The average age at time of surgery was 12+2 y.o. with a average follow-up of 10 yrs.
This study is the largest collection of patients treated operatively for dysplasia in association with CMT. Chart review focused on the pre and post operative pain level and ambulation. Radiographic measurements included: neck shaft angle, acetabular angle (Sharp's angle), acetabular index, Wiberg's center edge angle.
RESULTS: Upon presentation 5 of 8 were symptomatic for mild pain, and 4 of 8 complained of a limp. Hip dysplasia was unilateral in 3 pts. and bilateral in 6 pts. Post operatively 6 of 9 patients had no pain. 2 of the 3 asymptomatic pts. developed a limp, both had bilateral VDRO.
The types of surgical procedures were varied:
Types of pelvic osteotomy:
R Salter osteotomy / shelf.
L Chiari osteotomy / shelf.
Combined proximal femoral varus rotational osteotomy:
The average neck shaft angle pre op 153.7* / post op 142.7* (6 tx with VDRO).
The center edge angle, acetabular index / angle all improved post op with CE angle >25*.
The earlier surgical procedures were noted to have a higher rate of complications. The initial and short term complications included sciatic nerve injury, prolonged rehab., new limp. The long term complications included the progression of DJD, requiring conversion to a total hip arthroplasty. The patients treated with reconstructive pelvic osteotomy were without pain except for 1 patient from the original study who under went total hip arthroplasty at 17 years post- op the index procedure. The patients treated with salvage procedures including shelf and Chiari were doing well but complained of mild to moderate pain with activity.
DISCUSSION: In 1985 Kumar et al. described five girls with CMT and hip dysplasia from three families. The initial short term results of operative management in these patients were encouraging. This study followed four of the initial five patients an additional ten years with post-op follow up of 12 to 19 years. An additional five patients were included with follow up ranging from 2 to 9 years. The operative treatment of hip dysplasia associated with CMT at long term follow up continues to show satisfactory results. One of nine patients required an additional surgical procedure (THA) secondary to degenerative joint disease. Patients reported a persistent limp after proximal femoral varus rotational osteotomy. Reconstructive pelvic osteotomy showed a decrease in reported pain. The hip dysplasia in Kumar's original group and in this expanded group was either minimally symptomatic or asymptomatic at presentation. A high index of suspicion is needed for the diagnosis of this dysplasia.
CONCLUSION: The surgical treatment of dysplasia in the symptomatic patient is necessary to prevent further subluxation and decrease the likelihood of DJD. Osteotomy to address either pelvic or acetabular dysplasia is required. Rigid fixation is mandatory, and early mobilization is beneficial. Avoid excessive varus since a persistent limp may develop. The use of newer acetabular reorientation osteotomy may improve outcome. Consider the use of a Salter, Pemberton, or Dega. Take extra care to avoid pressure on neural structures since they tend to be hypersensitive. To objectively document the reported limp patients should be evaluated by physical exam or gait analysis.
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