Vascularized Interphalangeal Unicondylar Transfer effective technique for complicated injuries of Interphalangeal joints

Interphalangeal joints (IPJ) play a key role in hand function for performing activities of daily living and are frequently involved in complicated injuries resulting in significant functional limitations such as secondary arthritis and stiffness being the most challenging. In adult patients with more than 5 mm bone loss of the proximal articular surface who request a functional interphalangeal joint with minimal pain a vascularized joint transfer is a treatment choice.

A unicondylar loss more than 5 mm wide in a 22-year-old carpenter is reported and illustrates the experience with a vascularized unicondylar transfer showing the advantages compared to the "classic" total joint transfer or distal interphalangeal (DIP) joint arthrodesis. By using this technique at the 12-month follow-up, the authors (Stefano Lucchina et al) achieved no donor site complications, a good graft alignment, a good joint congruity, complete bone healing and a normal vascular patency with no signs of bone malunion or resorption of the graft.

Dimensions of the desired graft are determined from radiographs of the injured digit and the toes of the donor foot. The recipient site is prepared via a midlateral incision and a radical debridement of local soft tissues with identification of all missing elements is performed. The selected palmar digital artery at the middle phalanx (P2) is prepared and a dorsal vein of equivalent diameter is chosen. The size of the bony defect and the required length of vessels are then measured intra-operatively for a short transfer. The defect is templated and a corresponding osteochondral graft is harvested from the head of the 2nd toe proximal phalanx (P1) of the ipsilateral foot.

The toe dissection is carried out through a 4 cm curvilinear incision centered on the dorsal side of the PIP joint and extended to the 2nd web. Two-thirds of the P1 head are harvested with a saw blade osteotomy. One dorsal vein with a bulky fat cuff and the plantar lateral digital artery is dissected in the second web to guarantee the vascular contribution to the composite tissue graft. The digital nerve is also harvested to improve the vascular network of the graft or to reconstruct a concomitant nerve lesion. A slightly larger graft than required is harvested, allowing for in situ adjustment. The toe phalanx is trimmed to size and shaped to fit into the recipient bone.

The osteochondral graft and medial collateral ligament, partial extensor tendon, the ipsilateral artery, vein and digital nerve can be harvested and transferred to the finger. The toe PIP joint is fused with one axial 1.4 mm K-wire after resecting the remaining interphalangeal surfaces. The osteochondral graft is fashioned to be congruent with the contour of the remaining articular surface and is secured to the recipient P2 head with 2 transverse 1.0 mm K-wires. All other composite tissues are sutured to the recipient site. The remnants of the palmar plate of the DIP joint are secured with one mattress suture to prevent secondary DIP joint dorsal instability. The perivascular fat is positioned over the skin loss, one palmar digital artery and one dorsal vein are then anastomosed with 10/0 sutures.

The collateral ligament is secured with double "U" sutures with 4/0 polyester suture and the extensor tendon in zone I is reconstructed with the grafted extensor tendon with a double mattress suture with 4/0 polypropylene sutures. A full-thickness skin graft 1×1 cm wide is harvested from the ulnar side of the volar wrist and transferred on the fat cuff for final coverage. Prompt perfusion of the fat and small perforator vessels from the digital artery to the condyle is checked after tourniquet deflation.

The finger was immobilized in a thermoplastic splint including the PIP joint for the first two weeks and post-operative management included elevation of the hand and foot. The patient was discharged in one week with a protective boot (VACOped®). An early mobilization protocol of the injured finger was started on day 7, ranging the PIP joint 0 to 45° of flexion in the first two weeks, and increasing to full motion over four weeks. Passive and active-controlled mobilization was started after three weeks at the DIP joint, ranging the PIP joint 0 to 30° of flexion over 8 weeks until K-wires removal. At 8 weeks postoperative the two K-wires were removed from both finger and foot and the patient started to perform exercises of free mobilization against resistance. At 12-month follow-up performed by an independent hand therapist, a pain-free active PIP joint range of motion (AROM) of 10–85° and DIP ROM of 10–50° were obtained, with a grip strength of 42 lbs. Therefore, the clinical result was classified as "excellent" according to the evaluation method established by Ishida and Ikuta.

Further reading:

Is a Vascularized Interphalangeal Unicondylar Transfer Worth the Eforts? Surgical Technique and Clinical Application

Stefano Lucchina, Takako Kanatani, Marco Guidi

Indian Journal of Orthopaedics (2022) 56:1464–1468

https://doi.org/10.1007/s43465-022-00664-x