Clinical features and treatment of unilateral congenital upper limb myohypertrophy

Abstract

Objective To investigate the clinical features and treatment principles of unilateral congenital upper limb myohypertrophy.Methods A retrospective review of the cases of unilateral congenital upper limb myohypertrophy treated by the author from May 1992 to October 2012 was conducted.There were 12 cases with 7 males and 5 females.Patients' age averaged 5.5 years (range,3 to 17 years).They had the following clinical and morphological characteristics:congenital; unilateral hypertrophy of the upper extremity on both the flexion and extension side; more severe involvement of the hand than the forearm and upper arm with splayed fingers and broad hand; hyperabduction of the thumb towards radial and palmar side with a hypermegalia web space; ulnar/radial deviation and flexion deformity at the metacarpophalangeal joints (similar to windblown hand deformity) most prominent in the index and middle fingers.When primary or secondary macromelia is excluded,clinical diagnosis of unilateral congenital upper limb myohypertrophy could be made based on the above characters.Final diagnosis depended on the intraoperative findings of multiple aberrant intrinsic and extrinsic muscles with abnormal origin/insertion and orientation,and increased volume.All these 12 patients had functional impairment of the hand and went through 1 to 4 operations which included coarctation of the thumb web space,debulking of the thenar and hypothenar eminence,excision of aberrant muscles,stabilization of the metacarpophalangeal joint central slip,metacarpal osteotomy,skin release and dermatoautoplasty at the volar aspect of the metacarpophalangeal joint.Intraoperatively,the abnormal conditions of muscles in the operation area were carefully explored.These surgical procedures were carried out individually or simultaneously when up to 3 of them were combined at the same time.Results All the patients were followup by the surgeon for an average of 2.5 years.The radialhyperabduction of the thunb was reduced by an average of 25°.22 joints were underwent operations to correct lateral deviation,and 4 had recurrence.The osteotomy healed in all 5 cases.Flexion deformity of the metacarpophalangeal joints was improved by an average of 12°.60％ of the parents were satisfied with the appearance of the limb while 40％ were not.As for functions of the operated limb,50％ of the parents were satisfied versus 50％ dissatisfied.Conclusion Unilateral congenital upper limb myohypertrophy is a rare congenital anomaly with independent morphological characteristics.The appearance and function of the hand are severely affected,mainly attributed to congenital aberrant intrinsic and extrinsic muscles with abnormal insertions and orientation,and increased volume.Surgical corrections can partially improve the appearance and function of the hand. Key words: Upper extremity deformities, congenital; Retrospective studies; Treatment outcome; Morphological characteristics