Abstract

Patients with skeletal dysplasia are prone to developing advanced degenerative knee disease requiring total knee replacement (TKR) at a younger age than the general population. TKR in this unique group of patients is a technically demanding procedure due to the bone deformity, flexion contracture, generalised hypotonia and ligamentous laxity. We set out to retrospectively review the outcome of 11 TKR's performed in eight patients with skeletal dysplasia at our institution using the SMILES custom-made rotating-hinge total knee system. There were 3 males and 5 females with mean age 57 years (range, 41–79 years), mean height 138 cm (range, 122–155 cm) and mean weight 56 kg (range, 40–102 kg). Preoperative diagnoses included achondroplasia, spondyloepiphyseal dysplasia, pseudoachondroplasia, multiple epiphyseal dysplasia, morquio syndrome, diastrophic dysplasia and Larson's Syndrome. Patients were followed clinically and radiographically for a mean of 7 years (range, 3–11.5 years). Knee pain and function improved in all 11 joints. Mean Knee Society clinical and function scores improved from 24 (range, 14–36) and 20 points (range, 5–40) preoperatively to 68 (range, 28–80) and 50 points (range, 22–74) respectively at final follow-up. Four complications were recorded (36%), including a patellar fracture following a fall, a tibial periprosthetic fracture, persistent anterior knee pain and a femoral component revision for aseptic loosening. Our results suggest that custom rotating-hinge TKR in patients with skeletal dysplasia is effective at relieving pain, optimising movement and improving function. It compensates for bony deformity and ligament deficiency and reduces the need for corrective osteotomy. Patellofemoral joint complications are frequent and functional outcome is worse than primary TKR in the general population.

Submission endorsed by Mr Peter Calder, Consultant Orthopaedic Surgeon and Society member

Malformation and hypoplasia of the clavicle can result in pain, impaired function, restricted shoulder movement, subjective feeling of instability and cosmetic deformity. There are no reports of clavicle lengthening by osteotomy and distraction osteogenesis (DO). This is a retrospective review of 5 patients (7 clavicles) who underwent clavicle lengthening by DO using a monolateral external fixator for clavicular hypoplasia. There were 3 males and 2 females with mean age 15 years (9 to 23) and mean follow-up 21 months (8 to 51). Preoperative diagnoses included Klippel-Feil syndrome, cleidocranial dysplasia with torticollis, congenital myopathy and Noonans syndrome and obstetric brachial plexus injury. Mean length gained was 31 mm (15 to 41) which represens an average of 24.7% of overall bone length. Mean time in fixator was 174 days (161 to 263) and mean external fixation index was 56 days/cm. Two patients required internal fixation following fixator removal to consolidate union and one required additional internal fixation for atrophic regenerate. Mean preoperative oxford shoulder score improved from 28.5 to 41 and all patients were extremely satisfied with their result. Two patients developed pin site infections. Clavicular lengthening by distraction osteogenesis for congenital clavicular hypoplasia is a previously unreported technique that enables gradual correction of deformity without risking brachial plexus traction injury following acute correction. It has the potential to improve shoulder pain, function, range of movement and cosmesis. Distraction ≥25% of overall bone length may require additional plate fixation to consolidate union.