Finger dislocations comprise approximately 5% of upper extremity injuries, with the metacarpophalangeal (MCP) joint dislocation commonly resulting from forceful hyperextension following a fall on an outstretched hand ^[1]. These dislocations may involve the proximal phalanx dislocating dorsally or volarly, with dorsal dislocations being more prevalent ^[2]. MCP joint dislocations reducible through closed techniques are classified as simple dislocations, while those necessitating surgical intervention are characterized as complex dislocations ^[3,4]. Closed reduction techniques typically involve hyperextending the MCP joint and gently guiding the proximal phalanx back over the metacarpal head ^[5]. However, repeated failed reduction attempts can complicate a simple dislocation into a complex one. Longitudinal traction, which risks interposing the proximally torn volar plate within the MCP joint, should be avoided ^[6]. Although rare, complex dislocations mostly affect the index finger, followed by the thumb. In the little finger, they are extremely rare, and only sporadic cases have been reported ^[7,8]. The aim of the current case report is to present an uncommon case of a complex and irreducible dislocation of the MCP joint of the little finger, which was treated successfully with open reduction and stabilization of the affected MCP joint with a K-wire. The postoperative management that was followed is also highlighted.

A 48-year-old male presented to the Emergency Department (ED) of our hospital with a left-hand injury sustained during a soccer match, caused by being kicked by an opponent. Clinical examination revealed pain, deformity, and restricted range of motion in the little finger. The patient had no significant medical or surgical history and reported no paresthesia. Sensation and capillary refill time were normal in the affected finger. Radiographs (anteroposterior [AP], oblique views) depicted a dorsal dislocation of the metacarpophalangeal (MCP) joint (Fig. 1). Close reduction was attempted twice in the ED without success. The patient was informed about the need for surgery and taken to the operating room.

Initially, closed reduction under fluoroscopy was attempted under general anesthesia, which was again unsuccessful (Fig. 2). A volar approach to the MCP joint was undertaken using a 4 cm curvilinear incision. The A1 pulley was released, and the neurovascular bundle was carefully identified and preserved. The head of the fifth metacarpal was found to be dislocated to the volar side. Reduction was complicated by the dorsally displaced ruptured volar plate, which was trapped between the metacarpal head and the proximal phalanx. Using a Freer elevator as a lever and applying gentle traction and flexion, the intervening volar plate was pushed ventrally, allowing for the joint’s reduction. No osteochondral fragments were identified. The volar plate was reconstructed using absorbable sutures (Fig. 3). Closure was conducted in layers.

The reduction was confirmed under fluoroscopy. To stabilize the finger, a single 1.9 mm dorsal K-wire was placed at a 45° angle. The choice of a single wire was based on the intraoperative assessment, which confirmed adequate joint stability following reduction and volar plate repair. Given the absence of associated fractures or significant soft-tissue compromise, additional K-wires or external fixation were not deemed necessary. The patient was discharged on the day of surgery without any complications (Fig. 4). The K-wire was removed 15 days postoperatively (post-op), allowing for early mobilization and minimizing the risk of joint stiffness. The decision for a relatively short duration of immobilization was supported by the stability observed intraoperatively and during early follow-up.

After K-wire removal, the patient began gentle range-of-motion physiotherapy, progressively increasing the movement until achieving a full range of motion. Skin sutures were removed on postoperative day 21, slightly longer than standard practice. This timing was chosen due to the volar incision’s proximity to a high-movement area and to ensure optimal soft tissue healing. No signs of infection or wound-related complications were noted. At 2 months post-operative, the patient regained nearly normal range of motion in the MCP joint without pain. Hand grip and overall function were satisfactory, enabling a full return to pre-injury activities. Follow-up X-rays confirmed a proper and stable reduction. Finally, 3 months after surgery, the patient returned to his previous sports-related activities.

The MCP joint facilitates multi-directional motion ^[2]. Its capsule extends from the metacarpal neck to the base of the proximal phalanx and is reinforced by ligaments on all sides. The volar plate, a fibrocartilaginous structure, is located on the palmar side of the MCP joint ^[2,9]. Despite their rarity, MCP joint dislocations can occur in any finger ^[2,10,11]. In the index and little fingers, these dislocations may result from their susceptibility to trauma and the lack of stabilization provided by metacarpal ligaments ^[2,10,11]. Complications of these injuries include joint stiffness, especially when diagnosis is delayed. Late complications, such as degenerative arthritis or osteonecrosis, may also arise. In addition to delayed diagnosis and treatment, a poor prognosis may be linked to factors such as open dislocations, osteochondral fractures, repeated failed attempts at closed reduction, or prolonged immobilization ^[12]. The most commonly employed technique for reducing MCP joint dislocations involves flexing the wrist and proximal interphalangeal joint to relax the flexor tendons while applying pressure to the proximal phalanx base ^[2]. This technique was used in our case; however, two attempts at closed reduction in the Emergency Department were unsuccessful. As mentioned earlier, it is crucial to avoid longitudinal traction of the finger during reduction attempts, as this can transform a reducible dislocation into an irreducible one ^[2,9]. In complex dislocations, the metacarpal head usually becomes entrapped by the volar plate, flexor tendon, and lumbrical muscle ^[13]. In these cases, concerning the little finger, the abductor digiti minimi (ADM) and flexor digiti minimi (FDM) muscles are found at the lateral border of the MCP joint rather than the lumbrical muscles, highlighting an anatomical difference compared to the more frequently reported cases involving the index finger and thumb ^[6]. Surgical intervention is necessary in complex MCP joint dislocations, with two widely accepted approaches: the volar and dorsal techniques ^[7]. The dorsal approach, first described by Farabeuf in 1876, is considered less risky for injuries to the volarly displaced digital neurovascular bundle and provides sufficient exposure for managing osteochondral fractures that might require fixation or excision, based on their size or location ^[14]. However, it does not facilitate the repair of the volar plate, which theoretically could increase the risk of late instability, although this has not been widely observed in clinical practice ^[3]. The volar approach, introduced by Kaplan in 1957, offers the advantage of anatomical repair of the joint and volar plate but is more technically demanding due to the superficial position of the neurovascular bundle ^[7]. In addition, the lateral approach has been proposed for the reduction of complex MCP joint dislocations, though its use remains very restricted ^[15]. Moreover, percutaneous techniques that can be performed without direct visualization of the pathologic joint anatomy have been reported. These methods are straightforward, can be executed in the ED under local anesthesia, and may spare patients the need for open operation ^[9]. However, the data available on the outcomes and efficacy of percutaneous techniques are limited. In our case, since no osteochondral defect was noted preoperatively and considering the potential repair of the volar plate, the volar approach was chosen. A curvilinear incision was made over the MCP joint, and the A1 pulley was released. The neurovascular bundle was carefully identified and preserved, while the entrapped and ruptured volar plate was subsequently reduced and repaired to enhance joint stability and decrease the risk of future dislocation ^[3,7,10]. In general, after surgical reduction, the joint should be immobilized in a functional position for two to three weeks. Longer immobilization could result in degenerative arthritis or decreased range of motion ^[10]. We immobilized the finger at a 45° angle using a dorsal K-wire that was removed 15 days later. This immobilization ensures joint stability and promotes proper healing while minimizing the risk of postoperative complications associated with extended periods of immobilization ^[7]. The use of K-wire is considered more reliable for MCP joint dislocations, as these are unstable injuries ^[10]. Immobilization with a cast would require close follow-up and frequent splint adjustments as swelling subsides.

MCP joint dislocations, although easy to diagnose, should not be underestimated in terms of treatment. In cases where closed reduction proves challenging, the possibility of a complex dislocation requiring open reduction should be considered. Among the surgical approaches that have been reported for treating complex MCP dislocations, the volar and dorsal approaches are the most commonly used, each presenting advantages and disadvantages. The surgeon must be well-versed in both techniques to apply them appropriately.

Clinicians should take into consideration the possibility of a complex dislocation requiring surgical intervention when attempts at closed reduction of MCP joint dislocations are unsuccessful. In the little finger, the volar approach in such cases can yield satisfactory functional outcomes, provided there are no osteochondral defects. In parallel, reconstructing the ruptured volar plate might be crucial to minimizing complications in the affected joint.