Treatment and Outcomes of Missed Perilunate Dislocations: A Case Series.

Background Perilunate dislocations are devastating injuries that occur relatively rarely, accounting for only 7% of injuries to the carpus. Unfortunately, approximately 25% of these injuries are missed on initial evaluation. Acutely diagnosed perilunate dislocations may be successfully treated with ligament and osseous repair, depending on the injury pattern. Chronic dislocations, however, are primarily treated with salvage procedures. This case series was performed to investigate the outcomes of patients who sustained a perilunate dislocation that was diagnosed in a delayed fashion and look for any treatment patterns that could be more widely applied to future patients. Methods Patients presenting to a single institution between 2016 and 2018 with a perilunate injury that either presented in a delayed fashion or was missed on initial assessment were identified and their characteristics were evaluated. The surgical management of these patients was assessed as was their postoperative course at their 2-week, 6-week, 3-month, and 6-month clinic follow-up visits. Results Eight patients were identified with perilunate dislocations that were diagnosed in a delayed fashion. On average, these dislocations were diagnosed 133 days following the date of injury. All patients were males and 7/8 of them were between 17 and 20 years of age at the time of their injury (mean age: 25.5). They were treated with either primary repair, wrist fusion, proximal row carpectomy, or scaphoid excision and four-corner fusion (SEFCF). Both pain and range of motion improved following surgical management of these injuries. Conclusion Perilunate dislocations are rare injuries that are notorious for being diagnosed late, at which point primary repair is oftentimes no longer feasible. Salvage procedures are able to improve the range of motion and pain of patients who are found to have chronic dislocations. Our case series highlights the importance of treating each missed perilunate injury individually and avoiding a "one-size-fits-all" approach.

Current concepts: mallet finger.

Loss of the extensor mechanism at the distal interphalangeal (DIP) joint leads to mallet finger also known as baseball finger or drop finger. This can be secondary to tendon substance disruption or to a bony avulsion. Soft tissue mallet finger is the result of a rupture of the extensor tendon in Zone 1, and a bony mallet finger is the result of an avulsion of the extensor tendon from the distal phalanx with a small fragment of bone attached to the avulsed tendon. Mallet finger leads to an imbalance in the distribution of the extensor force between the proximal interphalangeal (PIP) and DIP joints. If left untreated, mallet finger leads to a swan neck deformity from PIP joint hyper extension and DIP joint flexion. Most mallet finger injuries can be managed non-surgically, but occasionally surgery is recommended for either an acute or a chronic mallet finger or for salvage of failed prior treatment.

Volar collapse after dorsal plating of comminuted distal radius fractures.

Between 1997 and 2001, 58 patients received dorsal plating for comminuted distal radius fractures. In 8 of these patients, subsequent collapse led to palmar flexion deformity, loss of rotation, and hardware prominence. In retrospectively reviewing this subgroup's range of motion, radiographic volar tilt, and complications, including tenosynovitis and extensor tendon rupture, we found that (1) with both palmar and dorsal comminution of distal radius fractures, dorsal plating may not prevent palmar cortex collapse; (2) deformity of the distal radius fragment causes palmar displacement of the radius relative to the intact ulna; (3) resultant incongruity at the distal radioulnar joint causes a significant loss of supination; and (4) palmar distal radius displacement leads to dorsal hardware prominence and may contribute to tenosynovitis and attritional extensor tendon ruptures.