71 Scaphoid Revision Nonunion
71.1 Patient History Leading to the Specific Problem
This man was hit by a soccer ball at the age of 18 years. X-rays were taken 1 week later with no signs of fracture. Because of persistent pain, new X-rays were done 1 year later, showing proximal pole pseudarthrosis of the right scaphoid. Colleges in Austria then performed a nonvascularized cancellous bone transplantation from the iliac crest and fixed the scaphoid using a scaphoid screw by a dorsal approach. After the surgery, he was put in a cast for 8 weeks.
Due to persistent nonunion, 1 year later a shock wave therapy, followed by another 8 weeks of immobilization, was performed in another hospital in Vienna. The patient was sent to the author 5 years after the accident in a situation as described in the following section.
71.2 Anatomic Description of the Patient’s Current Status
The patient has no signs of osteoarthritis in the radiocarpal and midcarpal joint (▶Fig. 71.1). The alignment of the carpal bones is normal. He still has a good range of motion. Grip strength is less than on the opposite side.
71.3 Recommended Solution to the Problem
In the author’s experience, saving the proximal pole by use of an osteoperiosteal free flap or avascular graft from iliac crest gives only unsecure healing prognosis. So a complete replacement of the proximal pole of the scaphoid by use of a medial free vascularized osteochondral graft from the medial femoral condyle (MFC) is the author’s recommended treatment to avoid a salvage procedure like a proximal row carpectomy or a midcarpal fusion.
In January 2006, the author performed his first osteochondral free flap from the MFC for the reconstruction of the proximal scaphoid pole. Now, 12 years later, he has replaced nearly all local pedicled bone flaps as well as free microvascular iliac crest grafts for carpal indications by free microvascular grafts from the medial and the lateral region of the knee. Since January 2006, the author has performed more than 280 of these grafts, 179 from the medial trochlea (MFC-[C]) and 101 from the lateral trochlea (LFC-[C]).
In the author’s practice, the healing rate of these grafts is superior compared to all the different free and pedicled flaps that he used before. The use of supramicrosurgical techniques is trainable; the insertion and stabilization of the graft remains challenging.
In scaphoid nonunion both, the MFC-(C) and the LFC-(C) can be successfully applied. Depending on the indication, the proximal or distal pole can be completely replaced or the flap can be applied as an inlay graft without cartilage.
71.4 Technique
The patient is placed in a supine position with pneumatic arm and leg tourniquet. The donor vessels are prepared first (▶Fig. 71.2). When available, the author mainly uses the palmar branches of the radial artery in an end-to-end fashion with a USP 10–0 or 11–0 suture. Alternatively, the radial artery can be used for an end-to-side anastomosis. For venous drainage, the deep accompanying veins or superficial skin veins can be used either in an end-to-end or in an end-to-side fashion. To avoid kinking, the author prefers a short pedicle. The further preparation is radial to the flexor carpi radialis tendon. The nonunion is exposed and it is decided whether to keep the proximal pole and use a medial femur graft without cartilage as an interposition graft or to replace the proximal pole. If the proximal scaphoid is avital, it is resected “on bloc” or gradually and an osteochondral flap is performed. The scaphoid fossa is inspected and as far as valuable the corresponding lunate and hamate.
Fig. 71.1 (a, b) X-rays presenting persistent scaphoid nonunion. (c) Corresponding CT scan of the same patient.
Then a template out of bone cement is formed to reduce the donor morbidity and to keep the graft as small as is necessary, especially in the cartilage-bearing area of the knee joint (▶Fig. 71.3). The author uses bone wax or bone cement in a silicon sheet to form the template. On the template, the author marks the planes (distal scaphoid, capitate, lunate, and cartilage).
Now, the flap can be harvested. The flap (medial condyle osteochondral flaps; MFC-C) is based on either the descending genicular or the medial superior genicular artery. The descending genicular artery is described to be present in 89% of the cases. The descending genicular artery arises from the superficial femoral artery and vein proximal to the adductor hiatus at a mean of 13.7 cm proximal to the joint line. Should it be absent or too small, the medial superior genicular artery is larger and should be selected instead. The surgical approach is through a longitudinal skin incision overlying the adductor magnus in the distal medial thigh. By retracting the vastus medialis anteriorly, the descending genicular vessels are found on the adductor magnus tendon and the superomedial genicular vessels are between the proximal medial condyle and the adductor tendon. These vessels form an arching arcade on the surface of the MFC.
Loop magnification (×2.5–4.5) is strongly recommended. In a bloodless field, the incision starts at the level of the knee joint and runs mid-sided proximally.
The fascia is opened in a longitudinal direction (▶Fig. 71.4). The vastus muscle is mobilized anteriorly. The ligated perforator leads you to a superficial and then deep periosteal network of vessels. A longitudinal branch supplies the periosteum and the distal femur and a transverse ascending branch supplies the proximal anterior articular cartilage. The arteria and the veins can now be dissected epiperiosteal in direction to the popliteal vessels. For complete pole replacement, the ascending osteochondral branch is selected, the proximal end of the cartilage is palpated, and the knee joint is carefully opened. Closed to the graft, the epiperiosteal dissection is changed into a subperiosteal one. According to the template, the graft is cut with an oscillating saw. There is no need to make a cut in the cartilage surface opposite to the patella (hard to be reached) of the knee; it can be carefully broken out if the other cuts have the same deepness. (The author measures or makes a mark on the saw.)
