Cartilage hair hypoplasia: characteristics and orthopaedic manifestations

PURPOSE

Cartilage hair hypoplasia (CHH) is a rare metaphyseal chondrodysplasia characterized by short stature and short limbs, found primarily in Amish and Finnish populations. Cartilage hair hypoplasia is caused by mutations in the RMRP gene located on chromosome 9p13.3. The disorder has several characteristic orthopaedic manifestations, including joint laxity, limited elbow extension, ankle varus, and genu varum. Immunodeficiency is of concern in most cases. Although patients exhibit orthopaedic problems, the orthopaedic literature on CHH patients is scant at best. The objective of this study was to characterize the orthopaedic manifestations of CHH based on the authors' unique access to the largest collection of CHH patients ever reported.

METHODS

The authors examined charts and/or radiographs in 135 cases of CHH. We analyzed the orthopaedic manifestations to better characterize and further understand the orthopaedic surgeon's role in this disorder. In addition to describing the clinical characteristics, we report on our surgical experience in caring for CHH patients.

RESULTS

Genu varum, with or without knee pain, is the most common reason a patient with CHH will seek orthopaedic consultation. Of the cases reviewed, 32 patients had undergone surgery, most commonly to correct genu varum.

CONCLUSION

This paper characterizes the orthopaedic manifestations of CHH. Characterizing this condition in the orthopaedic literature will likely assist orthopaedic surgeons in establishing a correct diagnosis and appreciating the orthopaedic manifestations. It is important that the accompanying medical conditions are appreciated and evaluated.

Surgical treatment of symptomatic accessory tarsal navicular

We report a retrospective review of 50 consecutive patients (75 feet) with chronically symptomatic accessory tarsal naviculars that failed to improve with conservative treatment. Surgical treatment consisted of excision of the accessory tarsal navicular or medial protuberance of a prominent cornuate-shaped navicular combined with simple replication of the tibialis posterior tendon without altering its course. Good and excellent results were obtained in 45 (70 feet) of the 50 patients (90%). The procedure has a low rate of minor complications, is easy to perform, and is extremely well accepted by the patients.

Redisplacement after closed reduction of forearm fractures in children

Reangulation and displacement after closed reduction of pediatric forearm fractures were reviewed in 90 patients treated with 1978-1984. All fractures were remanipulated and followed to union. No complications occurred and all had a functionally satisfactory result. Both intrinsic and extrinsic factors were identified as contributing to the complication of reangulation/displacement. Nonepiphyseal fractures were safely remanipulated up to 24 days postfracture, with the majority at 1-2 weeks. We conclude that 7% of pediatric forearm fractures treated by closed reduction are subject to reangulation and/or displacement following routine acceptable primary treatment, and that remanipulation provides a safe, effective means to obtain and maintain reduction.

Use of pins and plaster in the treatment of unstable pediatric forearm fractures

The treatment of unstable forearm fractures in children remains a challenging and controversial subject. There are times when more rigid fixation is needed to obtain and maintain fracture reduction. Open reduction/internal fixation or intramedullary nailing can be avoided by the use of the technique of pins and plaster. This study reviewed 20 forearm fractures treated between 1978 and 1984. All fractures healed uneventfully in satisfactory alignment. No complications were encountered. We conclude that the method of pins and plaster is a safe and reliable method to treat unstable pediatric forearm fractures.

Maturation factors in slipped capital femoral epiphysis

Several maturation factors relative to growth and epiphyseal development were reviewed retrospectively in 191 patients with slipped capital femoral epiphysis, including bone age, height and weight, thyroid functions, sex hormone levels, and growth hormone levels. Seventy-one percent of 138 patients had weights above the 80th percentile. Active thyroid (T3) was significantly low in 25% of 80 patients studied. Testosterone levels were markedly depressed in 76% of 64 patients tested. In this same group, 87% had low growth hormone levels. The consistently low testosterone and growth hormone levels, along with a tendency toward hypothyroidism, lend support to the biochemical theory of a delicate hormonal imbalance in slipped capital femoral epiphysis.