25

A healthy 25-year-old man presented to the ED after accidentally injuring his left hand with a circular saw while cutting lumber.

On presentation, the patient had a 10-cm dorsal hand laceration at the level of the metacarpophalangeal (MCP) joints of the index, middle, ring and small fingers. All fingers were well perfused with normal oxygen saturation in all digits and had intact sensation. On initial radiographs, he was found to have fractures of the metacarpals of the index, middle and ring fingers, as well as the proximal phalanx of the small finger (Figure 1). The same day, he was taken to the OR for irrigation and debridement and surgical fixation of the fractures of the left index, middle and ring finger metacarpals, as well as small finger proximal phalanx. We also performed tendon repairs of the extensor pollicis longus tendon, extensor indicis proprius tendon and extensor digitorum communis tendons of digits two to five (Figure 2).

At the 4-month postoperative visit, he had a complaint of stiffness in the left ring and small fingers. On examination, he had extensor lags of 7° at the ring finger MCP joint and 10° at the small finger proximal interphalangeal (PIP) joint and limited small finger PIP joint flexion from 10° to 30°. Radiographs demonstrated hypertrophic nonunion of the index metacarpal (Figure 3).

The following week, he underwent irrigation and debridement and nonunion repair of the left index metacarpal fracture, as well as ring and small finger extensor tenolysis and small finger PIP joint dorsal capsulotomy (Figure 4). Purulence was noted at the index metacarpal nonunion site. Intraoperative cultures were negative. The intramedullary screw was removed and revision fixation was performed using a 2-mm locking plate. The patient completed a 7-day course of antibiotic treatment with oral Bactrim (trimethoprim and sulfamethoxazole, Sun Pharma).

The patient presented with worsening pain and swelling over the ring finger MCP joint 11 months after his injury and index procedure. He had full range of motion of the ring finger MCP joint but continued to have a 20° small finger PIP joint extensor lag. The patient also had mild scissoring of his index finger over the middle finger. Radiographs were taken that demonstrated avascular necrosis of the ring finger metacarpal head, as well as persistent nonunion of the index finger metacarpal (Figure 5).

See answer below.

We discussed treatment options for avascular necrosis of the ring finger metacarpal head in addition to repeat nonunion repair of the index finger metacarpal fracture. After considering various treatment modalities for the ring finger, we decided on MCP pyrocarbon arthroplasty to provide pain relief while maintaining range of motion. For the index finger, we recommended nonunion repair with distal radius autograft and repair of the MCP joint index finger radial collateral ligament as he also had radial laxity of the MCP joint.

The patient was positioned supine on the operating table with a hand table. Following IV sedation, a Bier block was administered by the anesthesiology team. The left upper extremity was prepped and draped in the usual sterile fashion.

A longitudinal incision was made over the dorsal aspect of the index finger metacarpal through skin and subcutaneous tissue. The extensor tendons were retracted, and the periosteum was sharply elevated off the index metacarpal. The prior plate over the index metacarpal was removed and an osteotome was used to mobilize the nonunion site which was then debrided with a curette. The patient had a hypertrophic nonunion. Next, a distal radius autograft was harvested from the distal radius. A longitudinal incision was made over the dorsal aspect of the left wrist just ulnar to Lister’s tubercle. From this incision, a 1-by-1-cm corticocancellous bone graft was harvested off Lister’s tubercle as well as cancellous bone graft. The cancellous bone graft was packed into the nonunion site along with the 1-by-1-cm corticocancellous bone graft.A 2-mm locking T-plate was contoured to the radial aspect of the index metacarpal followed by proximal and distal screw fixation. The index finger MCP joint was stressed under fluoroscopy and was noted to have significant radial laxity at the MCP joint. The patient had avulsion of the index finger MCP joint radial collateral ligament off its insertion at the base of the proximal phalanx. A 2.2-mm suture anchor (Arthrex) was placed over the radial base of the index finger proximal phalanx followed by advancement of the radial collateral ligament with the MCP joint in 30° of flexion and radial deviation. This stabilized the MCP joint.

A transverse incision was then made over the dorsal aspect of the left hand over the ring finger MCP joint through skin and subcutaneous tissue. The radial sagittal band was incised down to the joint capsule followed by dorsal capsulotomy. The patient had severe arthritic changes in the ring finger MCP joint with complete erosion of the cartilage over the metacarpal head. The medullary canal was opened using a 3-mm surgical burr followed by use of a starting awl. An alignment guide was used over the metacarpal and then connected to the cutting guide. The metacarpal neck cut was made using an oscillating saw. The canal was serially broached up to size 20. This was done under fluoroscopic imaging to ensure the broach was well centered. A size 20 trial was placed which appeared to be a good fit. The trial was removed, and the joint was irrigated with normal saline. The size 20 MCP pyrocarbon prosthesis (Integra) was placed and the joint reduced. The radial sagittal band was repaired with 4-0 nylon sutures and the incision was closed. The patient was placed in a volar short arm plaster splint with the MCP and PIP joints in full extension.

At final follow-up 6 months after his last surgery, the patient reported no pain or instability in his hand and demonstrated full composite extension and flexion of all digits (Figure 6) (Video). Radiographs at this visit demonstrated a healed index metacarpal fracture, as well as well-positioned ring finger MCP joint pyrocarbon prosthesis (Figure 7). He was satisfied with his function and released back to full activities with no restrictions.

Avascular necrosis of the metacarpal head, also known as Dieterich’s disease, is a rare phenomenon, first described in 1927. Fewer than 90 cases have been published since 1932, with most being case reports. The etiology of Dieterich’s disease is unknown and can be idiopathic; however, it is frequently associated with trauma, renal transplantation, systemic lupus erythematosus and steroid use. Literature reviews have reported that the disease is most common in males in their second decade and occurs most commonly in the dominant hand. The middle finger is most affected, followed by the ring finger. Multiple digit and bilateral involvement have also been described. There have also been a few case reports of simultaneous avascular necrosis of both metacarpal head and metatarsal head (Freiberg disease). A vascular anatomy study reported an absence of large nutrient vessels in 35% of metacarpal specimens, which may increase the risk of avascular necrosis at the distal metacarpal epiphysis as the heads have small pericapsular arterioles. Additionally, the prominent position of the metacarpal head can lead to frequent blunt or repetitive trauma, which could cause occult fracture and joint effusion which could tamponade vessels.

Presentations can range from an asymptomatic incidental finding to a painful, swollen and stiff joint with reduced grip strength. Radiographs can demonstrate advanced disease with joint flattening and incongruity, while MRIs can detect osteonecrosis even in occult cases through findings of bone marrow edema, subchondral fracture or joint effusion. There is no clear consensus on optimal treatment for this disease. Treatment options include nonsurgical management, such as rest, activity modification, orthoses and NSAIDs, as well as surgical options, which include debridement, decompression, curettage and bone grafting, flexion corrective osteotomy, osteochondral autograft transfer system, vascularized joint transfer, arthrodesis, arthroplasty and MCP joint denervation.

For patients with intact articular cartilage, curettage of the necrotic bone and bone grafting with autogenous cancellous bone or vascularized pedicled bone graft can be effective for treatment of avascular necrosis of the metacarpal head. However, if the articular surface is eroded, the two main options are arthrodesis or arthroplasty. Alternatively, osteochondral reconstruction with autogenous or allograft osteochondral plugs can be considered for small focal defects. MCP joint arthroplasty is commonly used as a treatment for patients with osteoarthritis and rheumatoid arthritis, but less commonly for posttraumatic arthritis. Ingo Schmidt reported a case of metacarpal head necrosis with secondary osteoarthritis of the metacarpophalangeal joint treated successfully with resurfacing total joint arthroplasty. Matthew R. Claxton, BS, and colleagues published on a series of 44 MCP joint arthroplasties in 30 patients (mean age of 63 years) and demonstrated significantly improved pain and function scores, with a 7% revision rate 5 years after surgery. Implant instability was the most common reason for revision surgery.