Dislocated Lunar Facet Fragments and Radioscapholunate Arthrodesis

79 Dislocated Lunar Facet Fragments and Radioscapholunate Arthrodesis

Christoph Pezzei

79.1 Patient History Leading to the Specific Problem

A 49-year-old man fell on his hand in November 2006. It resulted in a complex intra-articular distal radius fracture. The ulnar facet was displaced and the carpus was subluxated volarly (Fig. 79.1). Open reduction and internal fixation with a fixed-angle plate was performed on the next day. Focused on the small ulnar fragment, the plate was placed very distally and ulnar. The postoperative X-ray showed a good result (Fig. 79.2). A short arm cast was applied for 5 weeks. Although the plate was placed very carefully, the small ulnar fragment could not be addressed sufficiently. The X-ray 3 weeks after the operation showed a re-dislocation of the ulnar fragment and a palmar shift of the carpus (Fig. 79.3). The patient rejected the urgent recommended reoperation. This situation persisted for 6 months.

79.2 Anatomic Description of the Patient’s Current Status

The fracture healed in malunion. As a result of the volar subluxation of the carpus and hardware irritation, the cartilage of the lunate was completely destroyed (Fig. 79.4). The patient had constant swelling at the left wrist; pain occurred only during heavy working. The range of motion (ROM) in extension/flexion was 30–0-40 degrees. The forearm rotation was not affected.

79.3 Recommended Solution to the Problem

Anatomical reconstruction of the radiocarpal articular surface is not possible; the cartilage is destroyed and shows progressive osteoarthritis.

Wrist denervation is a successful treatment of pain in the wrist with some useful remaining ROM, but contraindicated with obvious inflammation or edema.

Wrist arthroplasty could be one option in severe arthritis. The primary reasons for wrist replacement surgery are to relieve pain and to maintain function in the wrist without heavy demands in daily use.

Total wrist fusion is an option for treating such cases. High fusion rates are reported, and good pain relief can be achieved, but especially in young people the loss of wrist motion causes limitations in performing their daily activities.

As the midcarpal joint was unaffected, a radioscapholunate (RSL) fusion as salvage procedures was our preferred method. Typically, RSL arthrodesis is carried out from a dorsal approach. The advantage of the volar approach is that previously placed hardware can be removed without an additional dorsal incision. Distal scaphoidectomy in RSL arthrodesis increases the ROM in flexion and radial deviation and decreases the level of pain.

79.3.1 Recommended Solution to the Problem

Wrist denervation for pain management.

Wrist arthroplasty in severe arthritis.

Total wrist fusion for pain relief, but it has limitations.

Our preferred method to increase ROM is RSL fusion.

79.4 Technique

The volar approach was used for hardware removal and RSL arthrodesis. The incision was extended distally to the radial side to expose the scaphoid sufficiently. Previous hardware was removed. The complete palmar rim of the radius was cut off using a chisel to ensure there was no tendon irritation from the incoming plate.

The distal quarter of the scaphoid is resected. This unlocks the midcarpal joint, decreases the rate of nonunion, and increases the postoperative ROM. The articular surfaces of the scaphoid, lunate, and distal radius were exposed under maximal extension. The cartilage surface was denuded until cancellous bone was exposed. During this procedure, particular care must be taken to avoid damage to the midcarpal joint. The scapholunate ligaments were intact and left untouched.

The extracted part of the scaphoid and palmar rim of the radius were used for the cancellous bone graft, and no additional bone harvesting was necessary. K-wires in the scaphoid and lunate are used as joysticks to control the position of the carpus. Then under image intensification, temporary fixation of the lunate and scaphoid to the radius was achieved with two 1.2-mm K-wires. It is very important to avoid any dorsal intercalated segment instability (DISI) or volar intercalated segment instability (VISI) position of the lunate.

For the final fixation, we use a straight polyaxial locking frame plate (Fig. 79.5). It is important that the plate is not placed too distally to avoid intra-articular placement of the screws. Two screws were placed in the lunate and scaphoid under image intensification. The variable angle locking system allows exact screw placement in the carpal bones. The K-wires are removed, and the cancellous bone graft is compacted (Fig. 79.6). The patient was put under postoperative immobilization using a short arm cast for 5 weeks.

Dec 2, 2021 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Dislocated Lunar Facet Fragments and Radioscapholunate Arthrodesis
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