METACARPAL AND PHALANGEAL LENGTHENING OF THE HAND;

UTILITY OF DISTRACTION OSTEOGENESIS

Abstract

Objectives: To present our experience of distraction osteogenesis in Metacarpal and Phalangeal lengthening of the hand and
analyze the factors which influence the period of healing. Design: Experimental study. Period: December 2008 to April 2011. Setting:
Department of Plastic and Reconstructive Surgery, Khyber Teaching Hospital, Peshawar. The patients were admitted through out-patient
department and detailed history, clinical examination and necessary investigations were carried out. Informed consent was taken. Distraction
has been performed in six metacarpal bones and four phalangeal bones in nine patients. The age ranged from 3 to 59 years. All the digits had
traumatic amputations. The injury was in the right hand (dominant) in 6 patients and in the left hand in 3 patients. An isolated injury to the thumb
was seen in 4 patients, while in the remaining patients other fingers had been injured. All patients were operated by the same surgeon using
similar lengthening technique. Patients were followed regularly and assessed for bone lengthening by clinical and radiological methods.
Results: The achieved elongation of the metacarpal bones varied from 26 mm to 30 mm (average 27.66 mm), and of the digital phalanges from
10 mm to 17 mm (average 13.5 mm). Average healing time was 2.05 months (range from 1.8 – 2.5). Average healing index was 0.75 month/cm
(range from 0.65 – 0.88). Complications observed were pin tract infection (3 cases), necrosis of free grafted skin (2 cases), delayed
spontaneous bone union (2 cases) and volar angulation (1 case). Webplasty was performed in all cases. Strength of pinch improved by an
average of 37% and that of grasp by 48% compared to the preoperative values. All patients were able to pick up a paper and a cup of water.
Conclusions: Distraction osteogenesis is a successful and reliable method for the lengthening of short metacarpals and phalanges. However,
severe complications such as stiffness, angulation, subluxation of the MCP joint and delayed union or non-union are associated with this
procedure. To avoid these complications, we suggest protection of the periosteum, refraining from distraction rates of more than 2×0.25 mm/day
and, if possible, avoid lengthening a bone by more than 40% or not more than 20 mm of the preoperative bone length.