Compression Screw Fixation of Lunate Fracture: Case Report and Review of the Literature

Abstract

Background  Isolated traumatic lunate fractures without other surgical carpal bone or ligamentous injuries are extremely rare, with few published reports available to guide management. Lunate fracture management is controversial, and depends on concurrent injuries of adjacent carpal bones, ligaments, risk of ischemia, and displacement.

Case Description  A 48-year-old right hand dominant man suffered a crush injury to the left hand caught between a forklift and a metal shelf. Radiographs and computed tomography imaging of the left hand and wrist were significant for a displaced Teisen IV fracture of the lunate. A dorsal ligament sparing approach was utilized to access, reduce, and fixate the fracture using a headless compression screw. After immobilization and rehab, at 9 months after initial injury, the patient was back to work on full duty without restriction and pleased with the results of his treatment.

Literature Review  A literature review of lunate fracture compression screw fixation was performed and revealed a total of three reports indicating successful treatment of fractures, with patients returning to full activity.

Clinical Relevance  Lunate fractures are rare, often missed, and treating these injuries can be challenging, particularly in the setting of acute trauma. Based on our limited experience, we believe that open reduction and internal fixation of isolated Teisen IV lunate fractures with a headless compression screw is a viable treatment modality with satisfactory outcomes.

Lunate fractures are rare injuries, with a reported incidence of approximately 1% of all carpal bone fractures. These cases of fractures are most typically seen in the setting of perilunate injuries or in advanced Kienböck's disease. Isolated traumatic lunate fractures without other surgical carpal bone or ligamentous injuries are rare, with few published reports available to guide management. We present a unique case of a patient with a crush injury resulting in a Teisen IV lunate fracture treated with compression screw fixation and a review of the relevant literature.

Case Report

A 48-year-old right hand dominant man suffered a crush injury to the left hand caught between a forklift and a metal shelf. Injuries noted on exam were a 3-cm laceration through the dorsoulnar wrist involving the digital extensor tendons, a 4-cm first web space laceration with exposed thenar musculature, and a 6-cm dorsal hand laceration overlying the long finger with exposed metacarpal bone and wrist capsule.

Imaging of the left hand and wrist was notable for a displaced Teisen IV fracture of the lunate ( Fig. 1A–C ), fracture of the distal first metacarpal, and small fracture fragments of the dorsal distal radius and trapezium. The scaphoid appeared in its normal anatomical position without apparent injury while subluxation of the third carpometacarpal joint was noted attesting to the initial severity of trauma. The patient was admitted, started on intravenous antibiotics, and taken to the operating room for open reduction and internal fixation (ORIF).

Fig. 1.

Plain radiograph and computed tomography images displaying Teisen IV fracture of the lunate.

A ligament sparing approach described by Berger et al ¹ was used to access the lunate fracture after it was determined intraoperatively that transcarpal percutaneous fixation through the triquetrum was not possible. The dorsal intercarpal ligament was elevated off of the lunate dorsally to access the fracture. Temporary fixation of the lunate was obtained using a penetrating towel clamp. Stable lunate fixation was achieved via a 2 × 12 mm headless Stryker (Stryker, Kalamazoo, MI) cannulated compression screw over a Kirschner wire (K-wire) ( Figs. 2 and 3 ). The patient's intraoperative exam demonstrated no axial instability in the remaining carpus and no frank lunotriquetral injury. The capitate, hamate, and 3rd/4th metacarpal heads did not require stabilization. The remaining superficial wounds were closed. The patient's postoperative course was complicated by cellulitis, which resolved with intravenous antibiotics and elevation. He was discharged home on postoperative day 2 with oral antibiotics.

Fig. 2.

Intraoperative dorsal view of fracture line (arrow).

Fig. 3.

Intraoperative fluoroscopy displaying Kirschner wire (K-wire) fixation and subsequent compression screw fixation of fracture.

Postoperative follow-up imaging showed stable anatomic position of the lunate ( Fig. 4 ). The wrist was placed in a splint with the wrist extended for 4 weeks postoperatively. At the 6-month postoperative mark, patient had improved range of motion and strength, but developed scarring and contracture at the first web space, requiring a double opposing Z-plasty with Y-V advancement flap reconstruction. At 9 months after initial injury, the patient was back to work on full duty without restriction. At 3-year follow-up via telehealth visit, the patient stated he was overall satisfied with the outcome of his surgery. A QuickDASH-9 score of 49.5 showed moderately reduced function in his affected wrist, which he reported compensating with his dominant right hand. Pain score of 2 was reported in the setting of using the left hand and wrist for gripping as well as carrying/load-bearing activities. Range of motion of the left wrist was estimated at 80% of the uninjured right wrist, with no difficulties in activities of daily living or social interactions.

Fig. 4.

Four-month postoperative radiograph displaying stable anatomic alignment and healing of lunate.

Discussion

We are not aware of previous reports on ORIF of an isolated Teisen-classified lunate fracture by single headless compression screw. Most reports of carpal bone fractures describe treatment with closed reduction and immobilization or open reduction and K-wire fixation. A literature review of lunate fracture compression screw fixation was performed and revealed a total of three reports indicating that lunate fractures can be resolved and patients can return to full activity.

Hand fractures account for approximately 19% of all reported fractures. ² Lunate fractures account for roughly 1% of all carpal fractures ³ and are typically found in the setting of perilunate fracture dislocations. These injuries typically occur after a fall onto an outstretched hand (FOOSH) and are commonly associated with scaphoid fractures. Isolated lunate fractures occur rarely and are usually found in the setting of Kienböck's disease. ⁴ The relatively large amount of insensate cartilage and the position of the lunate centrally amidst other carpal bones make clinical diagnosis based on acute pain alone difficult. ⁵ Up to 30% of lunate fractures are occult on initial radiographs. ⁴ In our case, the lunate fracture was noted on plain radiographs. Computed tomography (CT) is also recommended to characterize lunate injury and surrounding structures. Our protocol for preoperative CT imaging further displayed mild subluxation of the third metacarpal base as well as small nonoperative fractures of the trapezium and distal radius. Both CT and magnetic resonance imaging (MRI) modalities have been described in literature regarding traumatic lunate injury evaluation, ^{6 7} although there are no current guidelines for situational preference of one modality versus the other. A single-center retrospective study reviewed MRI evaluation of lunate injury, showing Kienböck's disease, ulnar impaction syndrome, and intraosseous ganglia were the most common etiologies of abnormal lunate signal. Less frequently seen were degenerative or traumatic injuries. ⁸ A separate study assessing arthroscopic versus MRI findings of lunate chondromalacia suggested that MRI can be considered for routine evaluation of articular cartilage defects. ⁹

Lunate fracture management is controversial, and depends on concurrent injuries of adjacent carpal bones, ligaments, risk of ischemia, and displacement/instability. Teisen I fractures are the most prevalent, with full body fractures such as Teisen IV and V being the least common. ¹⁰ Gelberman et al ¹¹ showed that, in the setting of Kienböck's disease, the proximal lunate is most likely to suffer from ischemic injury. Panagis et al ¹² had previously shown that 20% of lunates were supplied by a single palmar artery. More recently, Dubey et al ¹³ demonstrated that the lunate typically has at least two main vascular sources, originating from the dorsal and palmar branches of the radial artery and entering the lunate on its dorsal and palmar surface. This study also found minor contributions from the anterior interosseous artery and both intercarpal arches. ¹³ Thus, a Teisen IV fracture is likely to disrupt minor intraosseous vascular anastomoses without disrupting the main dorsal and volar blood supply to the lunate. ¹⁴

Isolated lunate fractures can also occur in the setting of high-energy trauma within the wrist. Although our patient had some minor ligamentous and bony injuries, most of the carpal structure and stability was maintained. Based on the injury pattern, it is likely that the force was transmitted directly to the lunate through the soft tissues in a dorsal-volar load. ORIF of perilunate fracture dislocations is usually via a dorsal approach, which was also implemented in our patient through a preexisting dorsal laceration.

Hsu and Hsu ¹⁵ described a case of a young manual laborer with osteogenesis imperfecta who suffered FOOSH injury 3 months prior to presentation that was treated with immobilization. ¹⁵ He was discovered to have an isolated chronic Teisen V pattern lunate fracture. They performed a dorsal open reduction and placed two microscrews (16 and 14 mm) across the fracture for fixation. This patient had bony union and resolution of symptoms at 7 months after operative fixation.

Dana et al ¹⁶ described the case of another young male who presented 3 weeks after FOOSH injury while snowboarding with signs and symptoms of scapholunate instability. Imaging revealed a Teisen III lunate fracture, with an avulsed dorsal fragment attached to the scapholunate ligament. An arthroscopic approach was utilized for percutaneous placement of a 3.5 × 13 mm cannulated screw for definitive fixation. The patient returned to full activity after 6 weeks.

Barrera-Ochoa et al ¹⁷ described a series of 11 patients who had Teisen V fractures of the lunate in the setting of Lichtman IIIC stage Kienböck's disease. ¹⁷ Dorsolateral radial osteotomy and lunate 2 mm headless compression screw fixation through an open dorsal approach was performed for each of these patients with stable union and persistent resolution of symptoms at the 3-year (average) follow-up mark.

Lunate fractures are rare, often missed, and treating these injuries can be challenging, particularly in the setting of acute trauma. Our case shows that single compression screw fixation resulted in stable alignment with primary healing, moderate resolution of pain, and return of acceptable range of motion without signs of avascular necrosis. Our patient reported moderate-range QuickDASH scores suggesting a favorable outcome. We believe that the unique nature of lunate injury, combined with single screw fixation, is clinically interesting and addresses elements of surgical management of carpus fractures.

Funding Statement

Funding None.