To evaluate effectiveness and safety of acute ulnar lengthening osteotomy in Madelung's deformity associated with Hereditary Multiple Exostoses (HME)

Seventeen ulnas in 13 patients had acute ulnar lengthening for HME associated forearm deformity. Defined radiographic parameters were compared pre- and post-operatively using student's t-test; ulnar variance, carpal slip, radial bowing, radial articular angle. All complications were noted.

Mean follow-up was 27 months (range 1.5 – 72months). An increase in ulna length by a mean of 15.4mm (range 4.5 – 29.3mm) was achieved acutely, corresponding to an increase of 9.3% of total ulnar length. Negative ulnar variance was improved from a pre-operative mean of 12.4mm (range 6.1–16.5mm) to a post-operative mean of 4.6mm (range 0–11.25mm) (p=<0.00001). Carpal slip was significantly improved by a mean of 2.2mm (p=0.02). No significant change in radial bowing (p=0.98) or radial articular angle (p=0.74) was observed. Inter-rater reliability was excellent (r=0.96, Pearson Correlation).

Three patients required second procedures for recurrence of deformity at 18 months – 6 years following their primary operation. There were no incidences of compartment syndrome, neurovascular injury nor infection. One ulna fractured intra-operatively requiring a longer plate. One patient had a non union which united on revision surgery.

Significant radiographic improvements in forearm and wrist alignment were seen with acute ulnar lengthening. The procedure is safe, with no compartment syndrome nor neurovascular injury and low complications rate. Recurrence rates in the skeletally immature patients are comparable to that reported with gradual lengthening. Acute ulnar lengthening for forearm deformity associated with HME has been demonstrated to be a safe, reproducible and effective surgical procedure.