Leg Length Equalization by Correction of Pelvic Obliquity and Acetabular Dysplasia

Lee, Duk Yong; Kim, Yong Hoon; Hwang, Kyu Chun

Abstract

Fixed pelvic obliquity refers to a composite deformity induced by contractures both above and below the pelvis and the elements of this deformity are frequently interrelated during the period of growth. From the functional standpoint, leg length discrepancy is caused by deformities of the pelvis and lower extremities, such as pelvic obliquity and acetabular dysplasia, as well as by inequality of true limb bone length, and these deformities either aggravate or compensate functional discrepancy. During fhe fourteen years period, from August 1968 to August 1982, at the Department of Orthopaedic Surgery, Seoul National University Hospital, we treated 35 cases of fixed pelvic obliquity and acetabular dysplasia associated with true or functional limb length discrepancy by means of lumbodorsal fasciotomy or pelvic osteotomies such as Salters innominate osteotomy or Steels triple osteotomy, combined, if necessary, with contralateral abductor fasciotomy to gain functional limb length as well as to improve posture and balance. In many cases of residual poliomyelitis, epiphysiodesis was also performed when indicated. These cases were reviewed and following observations were made: 1. Of the 35 cases, residual poliomyelitis with 29 cases (83%) was by far the main cause of leg length discrepancy. Cerebral palsy (2cases), Legg-Perthes disease (2 cases), and fibrous ankylosis secondary to septic hip (2 cases) comprised the remainder. 2. The male-to-female ratio was about equal, being 17 to 18. 3. The average age at the time of operation was 17.9 years, the youngest being 7 years and the oldest being 30 years. The average age at the time of current follow-up was 18.8 years. 67% of those followed was skeletally mature. 4. An average of 1.35cm of bone length was gained radiographically by pelvic osteotomies. Steels triple osteotomy was more effective in gain than Salters innominate osteotomy. 5. An average of 2.43cm of functional length when standing was gained radiographically by lumbodorsal fasciotomy alone. 6. An average of 2.61cm of functional length when standing was gained radiographically by lumbodorsal fasciotomy and combined contralateral Soutters or Campbells fasciotomy. 7. An average of 3.57cm of functional length when standing was gained radiographically by lumbodorsal fasciotomy and combined ipsilateral Steel's triple osteotomy. 8. An average of 1.73cm of functional lengthening when standing was corrected radiographically by ipsilateral Soutter's fasciotomy. 9. When lumbodorsal fasciotomy and Steel's triple osteotomy were combined with contralateral Soutter's or Campbell's fasciotomy, the average radiographic gain in standing length was 3.77cm. 10. Leg length discrepancy in terms of true bone length is conventionally corrected either by epiphysiodesis or bone shortening on the longer limb, or by bone lengthening on the shorter limb. We believe that when leg length discrepancy is associated with fixed pelvic obliquity, frequently aggravating the disability functionally, lumbodorsal fasciotomy and/or pelvic osteotomies on the shorter side and, combined if necessary, Soutters or Campbells fasciotomy on the longer side, can, in many instances, successfully correct or reduce functional limb discrepancy and improve balance, posture and function. Any residual discrepancy, true or functional, may then be corrected by conventional methods.