The Early Outcome Of the Bernese Periacetabular Osteotomy For Hip Dysplasia In Multiple Epiphyseal Dysplasia

Background:Multiple epiphyseal dysplasia (MED) is a rare congenital bone dysplasia. Patients with MED develop secondary hip osteoarthritis as early as third to the fourth decade. Currently, there is no consensus on how to prevent or slow the process of secondary hip osteoarthritis.The Bernese periacetabular osteotomy is a joint preserving surgery to reshape acetabulum and extend coverage for the hip, however, there is no established evidence of the effectiveness for the MED hips.Patients and methods:A retrospective series of 6 hips in 3 patients with multiple epiphyseal dysplasia treated with the Bernese periacetabular osteotomy were reviewed. The average age at the time of surgery was 14.3 years (range: 11.4 to 17.2 y). Radiographic parameters were analyzed preoperatively and 1-year postoperatively. The hip function was evaluated by the Harris Hip Score (HHS) before and after surgery. Results:The mean follow-up time was 1.7 years. The mean LCEA increased from 3.8° to 47.1° (p = .02), ACEA increased from 7.3° to 35.1° (p = .02), and AI decreased from 27.8° to 14.6° (p=.04). The femoral head coverage ratio increased from 66.8% to 100% (p= .02). The procedure achieved femoral head medialization by decreasing central head distance from 86.7mm preoperatively to 82.7mm postoperatively, however, without statistical significance. (p = .699). The improvement of clinical outcomes by mean HHS was significant from 67.3 preoperatively to 86.7 postoperatively (p=0.05).Conclusion:Bernese PAO is a feasible option for treatment of the hip problems in MED patients. It reshapes acetabular and femoral morphology 3-dimensionally. In our study, the short-term follow-up results showed obvious functional and radiographic improvement. A long-term follow-up is necessary in the future.

A Novel COMP Mutation in a Chinese Family with Multiple Epiphyseal Dysplasia

Background: Multiple epiphyseal dysplasia (MED) is a skeletal disorder characterized by delayed and irregular ossification of the epiphyses and early-onset osteoarthritis. At least 66% of the reported autosomal dominant MED (AD-MED) cases are caused by COMP mutations. Methods: We recruited a four-generation Chinese family with early-onset hip osteoarthritis, flatfoot, brachydactyly, and mild short stature. The assessment of family history, detailed physical examinations, and radiographic evaluations were performed on the proband and other family members, followed by the performance of whole-exome sequencing (WES). The pathogenicity of the candidate mutation was also analyzed. Results: We recruited an AD-MED family with 10 affected members and 17 unaffected members. The main radiographic findings were symmetrical changes in the dysplastic acetabulum and femoral heads, irregular contours of the epiphyses, a shortened femoral neck, and flatfoot. Lower bone density was also observed in the ankle joints, wrist joints, and knees, as well as irregular vertebral end plates. In the proband, we identified the missense mutation c.1153G>T (p. Asp385Tyr), located in exon 11 of the COMP gene. This mutation was assessed as “pathogenic” because of its low allele frequency and its high likelihood of co-segregation with disease in the reported family. Sanger sequencing identified the novel heterozygous mutation c.1153G>T (p. Asp385Tyr) in exon 11 of COMP in all affected individuals in the family. Conclusions: Our result underlined a key role of the Asp385 amino acid in the protein function of COMP, and confirmed the pathogenicity of the COMP (c.1153G>T; p. Asp385Tyr) mutation in AD-MED disease. We have therefore expanded the known mutational spectrum of COMP and revealed new phenotypic information for AD-MED.