Naoya Kashiwagi

Bilateral humeral lengthening in achondroplasia

Twenty humeral lengthenings were done on 10 achondroplastic dwarfs using the Ilizarov circular fixator. There were five female and five male patients from 6 years 11 months to 17 years 8 months of age (mean, 12 years 10 months) at the time of the operation. Mean length obtained was 7.8 cm (range, 3.5 cm–10 cm). External fixation time ranged from 105 days to 368 days (mean, 221 days). Healing index averaged 30 days/cm (27 days/cm when two patients with radial nerve palsy were excluded). Two half pins in one patient required replacement. Two humeral fractures occurred, one while in the fixator and the other after removal of the apparatus. Transient radial nerve palsy developed during lengthening in two patients, and lengthening was discontinued. Symptoms of radial nerve palsy resolved completely in both patients, but one patient required an additional surgery to explore the radial nerve for persistent paresthesia of the forearm. Although preexisting loose shoulders deteriorate during lengthening and sometimes cause pain and discomfort, they always resolve spontaneously as lengthening proceeds. Bilateral humeral lengthening was very effective for improving function and overall proportion in patients with achondroplasia.

Sequential magnetic resonance imaging in slipped capital femoral epiphysis: assessment of preslip in the contralateral hip.

Thirty-three images using magnetic resonance imaging (MRI) in 10 patients with slipped capital femoral epiphysis were evaluated. The MRI of affected hips delineated typical widening of the physis. Sequential MRI demonstrated the process of premature closure of the physis developing from the posterior portion anteriorly. In 4 of the 10 asymptomatic contralateral hips, physeal widening was clearly observed in the center or posteromedial region of the physis on T1-weighted images. We performed prophylactic pinning for the four cases showing physeal widening on MRI, and none of the other cases developed a slip. MRI accurately documented detailed features of slips, as well as physeal changes, and may provide indicative information on prophylactic pinning for contralateral hips.

Early characteristic findings in bowleg deformities: evaluation using magnetic resonance imaging.

We used magnetic resonance imaging (MRI) to evaluate bowleg deformities in infancy. Twenty-five tibiae of 13 infants were examined and divided into two groups based on MRI findings: group A had high intensity area in the medial epiphyseal cartilage on T2-weighted images. Group B had depression of medial physis and abnormal signal in the perichondrial region in addition to the epiphyseal lesion. At the final follow-up, all cases in group A demonstrated normal lower leg alignments, whereas five cases in group B showed characteristic roentogenographic findings of Blounts disease. The improvement rate of metaphyseal-diaphyseal angle was correlated with this classification. These findings suggested that abnormal findings in physis and perichondrial region might be preliminary findings in early stage of Blounts disease. The high intensity areas in the medial epiphyseal cartilage were commonly found among the cases with bowing deformities, which suggested that there might be a common pathomechanism between physiologic bowing and infantile Blounts disease.

Surgical Treatment for Permanent Dislocation of the Patella in Adults

Permanent dislocation of the patella in adults is a rare condition that presents with complete irreducible lateral dislocation of the patella, combined with secondary changes, such as valgus deformity and leg-length discrepancy. Because these secondary changes cannot heal spontaneously after skeletal maturation if left untreated, the patients frequently possess pathology not limited to the knee joint and extending to the whole lower extremity, such as malalignment or leg-length discrepancy, that can develop into osteoarthritis of the knee. However, to our knowledge, few surgeons advocate the significance of correcting the malalignment in treating adult patients. We treated a 34-year-old woman with permanent dislocation of the patella in a 2-stage surgery, consisting of first-stage correction of valgus deformity and limb shortening using a Ilizarov external fixator and second-stage realignment of the dislocated patella over the trochlea. A follow-up examination conducted 3 years after the second operation revealed plantigrade gait with normal alignment of the lower extremity without limping and medial thrust. The patella was tracking centrally in the patellofemoral groove. Radiographs showed a neutral mechanical axis of the lower extremity, no evidence of patellar subluxation, and no deteriorating osteoarthritic changes at the tibiofemoral joint. This case highlights the importance of correcting secondary changes, such as valgus deformity and leg-length discrepancy, to reduce the risk of future osteoarthrosis and postoperative dislocation, especially when these deformities are substantial.

The prevalence of the complications and their associated factors in humeral lengthening for achondroplasia: retrospective study of 54 cases.

The aim of this study is to evaluate the complications of humeral lengthening and their associated factors. Fifty-four achondroplastic patients were treated by bilateral humeral lengthening. Our original shoulder sling was sufficient to prevent shoulder dislocation. Pre-existing radial head dislocation was observed in 18 patients. Lengthening was accomplished in all cases without a decrease in the elbow function. Seven humeri fractured after the fixator removal. The risk factors for postoperative fracture were a waiting period of less than 5 days, a healing index less than 25, and the concave shape of the callus. There was no radial nerve palsy.