46 Painful Proximalization of the First Metacarpal after Trapeziectomy
46.1 Patient History Leading to the Specific Problem
A 71-year-old woman suffered from a painful stage III osteoarthritis of the basal thumb according to the Eaton and Littler classification. As surgical treatment, a trapeziectomy was performed. In the postoperative course, there were no complications. Six months after initial surgery, the patient still complained of pain at the base of the first metacarpal. This pain intensified especially with a firm pinch grip and power grip. The active elderly patient was restricted during her sports in the gym as well as in activities of daily living (ADLs) and wanted to get her condition improved.
46.2 Anatomic Description of the Patient’s Current Status
The clinical examination shows pressure pain over the base of the first metacarpal bone. The range of motion was unrestricted. Constant pain occurred over the former first carpometacarpal (CMC 1) joint when the patient performed a pinch or forced grip. The examination reveals a subluxation of the base of the first metacarpal bone. Under tension and pressure, the base of the first metacarpal bone moves 1 cm distally and proximally (▶Fig. 46.1). The Grind test is painful, increasing under pressure and disappearing under tension.
Plain X-rays of the CMC 1 joint show the proximalization of the first metacarpal without direct contact to the scaphoid bone (▶Fig. 46.2a). In a scan, contact between the ulnopalmar edge of the first metacarpal and the oblique surface of the trapezoid is confirmed (▶Fig. 46.2b).
46.3 Recommended Solution to the Problem
Revision surgery was performed. For this purpose, the oblique surface of the trapezoid to the former trapezium is vertically osteotomized (▶Fig. 46.3) in order to avoid contact with the base of the first metacarpal. In order to prevent a re-proximalization, the implantation of a piece of rib cartilage was carried out, which was implanted in the left trapezium space and fixed with a bone anchor on the distal scaphoid bone.
46.3.1 Recommended Solution to the Problem
• Partial horizontal resection of the trapezoid to avoid impingement of the first metacarpal.
• Maintain trapezial space height with the rib cartilage graft.
• Avoid dislocation of the graft with a suture anchor and 4 weeks of immobilization.
Fig. 46.1 Unstable base of the first metacarpal under (a) traction and (b) load.
Fig. 46.2 (a) Proximalization of the first metacarpal without direct contact to the scaphoid bone. (b) Impingement between the ulnopalmar edge of the first metacarpal and the oblique surface of the trapezoid.
Fig. 46.3 CT scan of the wrist. The red area demonstrates the amount of resection of the trapezoid to avoid impingement.
Fig. 46.4 After opening the previous trapezial space, the cartilage defect due to impingement of the first metacarpal is visible on the trapezoid surface at the bottom of the trapezial space.
46.4 Technique
The old scar is excised on the radiodorsal aspect over the CMC 1 joint. The incision is then widened to the proximal and distal direction (2 cm each). In the scar tissue, two sensory branches of the superficial radial nerve have to be microsurgically neurolysed. For this purpose, surgical loupes are highly recommended. This is followed by the exposure of the radial artery. Once these structures are secured, a longitudinal incision of the scar tissue between the base of the first metacarpal bone and the scaphoid bone is performed. The scar tissue is dissected to the side and the left trapezium space is exposed. If the first metacarpal bone is difficult to move, use scissors to dissect the base of the first metacarpal bone out of the scar tissue to mobilize the entire first ray distally. It is important to ensure that the insertion of the abductor pollicis longus (APL) muscle tendon is not detached in this case. After exposure, the oblique articular surface of the trapezoid can be inspected; often a cartilage wear can be seen (▶Fig. 46.4). If so, the trapezoid should be partially resected vertically, leaving a small amount of articular surface to the scaphoid on the ulna side. This prevents contact between the bones.
Subsequently, an approximately 1 × 1 cm large rib cartilage graft is removed from the opposite medial costal arch (▶Fig. 46.5). Therefore, an incision of about 3 to 4 cm over the costal arch at the level of the insertion of abdominis muscle is made in the transverse direction. After subcutaneous dissection, the anterior rectus sheath is opened transversely and the rectus abdominis muscle is split in longitudinal direction and pushed apart. Under the rectus abdominis muscle, the lower costal arch is exposed. Here the perichondrium is opened and the cartilage is exposed ventrally and dorsally with a sharp dissector. It is important not to slip too deep with the dissector to avoid an intrathoracic injury. After passing through the cartilage, it can be resected either with scissors or with small scaphoid chisels. The wound closure is done in layers.
The harvested cartilage is formed to the size of the trapezium space (▶Fig. 46.6a). To prevent later dislocation of the cartilage, a bone anchor is placed into the distal articular surface of the scaphoid next to the capitate. The graft is fixed in the cavity (▶Fig. 46.6b,c). The closure of the joint capsule is done with a 2–0 Monofile absorbable suture. An attempt should be made to close the joint capsule. Radial artery and the sensory nerve branches have to be protected in this step. The exact position of the first metacarpal bone has to be verified in an intraoperative X-ray control (▶Fig. 46.6d). A thumb forearm splint is used for immobilization first; after removal of the skin sutures, a CMC 1 joint orthosis can be applied. Immobilization is necessary for 4 weeks. Forced manual mobilization of the former CMC 1 joint is not allowed until completion of the eighth postoperative week.
