Abstract
A vascularised bone segment of the distal radius was harvested as a distally based flap to treat segmental metacarpal bone loss in three patients. One reconstruction followed resection of a giant cell tumour excision and the other two were to replace traumatic bone loss. The bone defects were in the second metacarpal in two cases and in the second and third metacarpal in one case and included three shaft and one distal metacarpal reconstruction. The mean length of the metacarpal defects was 6 cm. All of the flaps survived and no complications occurred at the donor site. Clinical and radiological union was established in all cases after an average of 3 months.
Many methods are reported in literature for the management of metacarpal segmental bone losses. Most use donor sites distant from the upper limb and many require microsurgical expertise.
We report three cases in which an osteofascial radial reverse flap was used to replace metacarpal bone losses without significant soft tissue defects.
CASE REPORTS
Case 1
A 55 year-old man sustained a machinery crush injury of the dorsum of his hand. The resulting defect included the extensor tendons to the index, middle and ring finger and the shafts of the second and third metacarpal bones (Figs 1 and 2). Bone reconstruction was performed after debridement at primary surgery. A reverse osteofascial radial flap 10 ×2.5 cm was harvested (Fig 3), split into two parts while retaining vascularity of both parts through the soft tissues and fixed with miniplates to restore the two metacarpal shaft defects which were both 4.5 cm in length (Figs 4 and 5). The extensor tendons were sutured and the donor site was closed directly. Bone union occurred 3 months after surgery. The ranges of motion of the metacarpophalangeal joints of the reconstructed rays were both 60° at 3 months.
Case 2
A wide resection of a giant cell tumour (Athanasian, 2005) involving the distal second metacarpal was performed on a 45 year-old woman (Fig 6). A bone spacer of acrylic cement was left in place for 6 months for the purpose of oncological follow up. After this period, the distal part of the metacarpal was reconstructed with a distally based osteofascial radial flap with reconstruction of the MCP (Athanasian et al., 1997) as a fibrous ankylosis between the end of the radial bone and the articular cartilage of the base of the proximal phalanx (Fig 7). The patient is free of tumour 3 years after the treatment, with a good aesthetic result and a range of motion of the MCP pseudoarthrosis of 70° (Fig 8). She experiences no pain in this joint except on forced passive flexion.
Case 3
A 34 year-old man sustained a shotgun injury to his left hand from close range which shattered the second metacacarpal bone, leaving a mid-shaft defect after debridement of 3 cm. A reverse osteofascial flap with a bone length of 3 cm was harvested and transposed at primary surgery to replace the missing bone of the metacarpal. The extensor tendons were repaired and the quality of the remaining skin was sufficient for primary closure. Postoperatively, the patient recovered well and the range of motion of the metacarpophalangeal joint of the reconstructed ray was 90°.
RESULTS
Rehabilitation consisted of early mobilisation of all digits with a protective wrist splint for 4 weeks. Rehabilitation was uneventful with no fractures of the radius.
The follow-up period ranged from 3.5 to 36 months. Clinical and radiological union was established in all cases after an average of 3 months. The functional results in terms of range of motion of the fingers of the involved rays were good and, in the giant cell tumour patient, no tumour recurrence was detected. No patient required secondary procedures for immediate or delayed complications.
The donor site of the radial flap was closed directly in all cases as no skin was harvested with these flaps. The donor sites all healed well. The cosmetic results of the hands were also good at final follow-up.
DISCUSSION
Distally based island and free osteocutaneous flaps provide vascularised bone reconstruction which achieves rapid bone union, undergoes little resorption and shows good infection resisting capabilities (Yuceturk et al., 1998).
The osteocutaneous radial forearm flap is widely used, both as a free flap and distally based on the ipsilateral hand (Yang and Morris, 2006). It provides good vascularised bone and is a very reliable method for metacarpal reconstruction. With this flap, up to 12 cm of nearly straight bone can be harvested. The bone can also be divided into two parts safely, with vascular continuity being maintained through the soft tissue adjacent to the bone, to allow double barrelling of the bone or for reconstruction of adjacent metacarpal bone defects. It is also less resource demanding than microsurgical free transfers. The only other option capable of providing enough bone as a distally based pedicled flap is an osteofascial posterior interosseous flap (Akin et al., 2002) or an osteofascial lateral arm flap with a pedicular extension in reverse YV flow (Martin et al., 1997) but these flaps are less reliable and reproducible. The disadvantages of this bone reconstruction is that only a thin segment of bone can be harvested without significant risk of radial fracture. This requires that both the reconstruction and the radius be protected for 4–6 weeks postoperatively. If this precaution is taken, radial fracture is uncommon. Double-barrelling of the reconstruction provides greater strength to the reconstructed bone of the hand.