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Hamate and CMC Fracture-Dislocation Fixation

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Overview¶
Hamate and carpometacarpal (CMC) fracture-dislocations require a treatment strategy dictated by displacement and associated instability. Undisplaced fractures may be managed conservatively with good results [2], while displaced fractures or those with metacarpal subluxation are better treated with open reduction and internal fixation to minimize residual deformity and dysfunction [2]. For ulnar CMC joint dislocations, nonoperative treatment is a successful option if diagnosis is early and a concentric, stable reduction is initially achieved, requiring close follow-up for the first week [11]. Timely diagnosis, adequate sedation with muscle relaxation, and gentle reduction maneuvers allow for near-anatomic reduction of acute closed dislocations of the second through fourth CMC joints, which are adequately treated conservatively with minimal disability at 7-month follow-up [15].
Operative management of CMC fracture dislocations results in good-to-excellent functional outcomes despite relatively high surgical complication rates [3]. Favorable outcomes were observed after open reduction and internal fixation of the hamate body fracture with interfragmentary screws combined with stabilization of the CMC dislocation with percutaneous Kirschner wires [1]. The clinically appropriate fixation method should be selected according to the experience of the surgeon and the degree and type of fracture and dislocation [5]. Open reduction and internal fixation is recommended for patients with delayed presentation of CMC fracture dislocations [8], as delayed diagnosis makes closed reduction difficult and is associated with less favorable radiographic outcome [9].
The superiority of any treatment strategy for little finger carpometacarpal joint fracture-dislocations cannot presently be determined, and higher quality comparative data is urgently needed [17]. Careful evaluation of intraoperative and postoperative imaging, particularly CT, is important to detect rare persistent palmar trapezoid dislocations that may be missed on standard radiographs [14].
Anatomy & Pathophysiology¶
Bony Anatomy and Kinematics¶
The hand skeleton comprises 27 bones, 19 of which are long bones [23]. The base of each metacarpal articulates with the distal row of the carpus [23]. The wrist possesses three axes of movement, permitting the hand to assume any spatial configuration [23]. The fifth metacarpal is semi-independent and articulates with the hamate [30]. It exhibits a range of flexion–extension of approximately 20 degrees, whereas the ring metacarpal has about 10 degrees of mobility in flexion and extension [30]. The second to fifth metacarpals are bound together by the deep transverse intermetacarpal ligament [30]. This structure is also named the interglenoid ligament because it ties together the anterior glenoid ligaments of the metacarpophalangeal articulations [30]. The opponens digiti quinti arises from the pisohamate ligament and the hook of the hamate, inserting onto the ulnar side of the diaphysis of the fifth metacarpal [27]. The abductor digiti quinti and flexor digiti quinti brevis arise from the fifth metacarpal [27].
Ligamentous and Soft Tissue Constraints¶
The lack of bony constraints of the CMC joint to the ring and small fingers adds to their propensity for injury [24]. In contrast, the central digits are more protected from deformity secondary to the stabilizing effect of the deep transverse intermetacarpal ligaments and bony constraints imparted at the CMC joint [24]. The motor branch of the ulnar nerve is in proximity to the fifth CMC joint [24].
Injury Mechanisms and Pathophysiology¶
The most common mechanism for CMC joint dislocations or fracture–dislocations of the fingers is an axial load with a clenched fist [24]. If force is applied when the metacarpal head is depressed, a dislocation of the fourth and fifth CMC joint will result [24]. In higher-energy injuries, a fracture of the base of the small finger metacarpal or of the hamate articular surface may occur [24]. Multiple CMC dislocations tend to be higher-energy injuries and carry a worse prognosis secondary to the energy imparted on the hand [24]. Hamate fractures constitute 2–4% of all carpal fractures, while hamate-metacarpal fracture-dislocations constitute 10–15% of carpometacarpal region fracture-dislocations [20]. The most common mechanisms for hamate body fractures are striking a solid object with a clenched fist (52%) and falls (22%) [19]. Dorsal oblique coronal hamate fractures are most commonly associated with punching injuries, whereas falls from height are more common in coronal splitting types of hamate fractures [18]. Concomitant fractures occurred in 82.8% of cases of coronal hamate body fractures with CMC instability, most frequently involving the fourth metacarpal base [18]. Persistent palmar trapezoid dislocations may be missed on standard radiographs and require CT for detection [14].
Fracture Morphology and Patterns¶
Coronal hamate body fractures are classified as dorsal oblique or coronal splitting types based on computed tomography findings [18]. In a retrospective review of 58 patients, dorsal oblique fractures occurred more frequently than coronal splitting fractures [18]. Dorsal oblique fractures were most commonly associated with punching injuries, while falls from height were more common in coronal splitting types [18]. Concomitant fractures occurred in 82.8% of cases involving coronal hamate body fractures with CMC instability, most frequently involving the fourth metacarpal base [18]. Hamate body fractures predominantly occur in the dominant arm of young adult males [19]. A review of 120 cases in the literature showed that 96% of patients with hamate body fractures were male, with an average age of 29 years, and 93% had injuries involving their dominant hand [19]. The most common mechanisms reported for hamate body fractures were striking a solid object with a clenched fist (52%) and falls (22%) [19]. In a specific study series, 100% of patients sustained injuries exclusively from striking a solid object with a clenched fist [19].
Classification Systems¶
The first classification of hamate fractures was established by Milch et al. in 1934 and does not include coronal fractures [20]. Cain’s classification focuses on the dislocation of the fifth CMC and further co-fractures of the hamate [20]. Ebraheim’s classification focuses on the course of the fracture line through the hamate body [20]. Ebraheim’s variant of subdivision is used for preoperative planning to provide information necessary for treatment considerations [20]. Treatment for carpometacarpal fracture-dislocations associated with hamate fractures should be individualized, taking into account the limitations of existing classification systems [19].
Clinical Presentation¶
Epidemiology and Demographics¶
Hamate fractures, encompassing hook and body fractures, account for 2–4% of all carpal fractures [20]. The hamate-metacarpal fracture-dislocation specifically constitutes 10–15% of carpometacarpal region fracture-dislocations [20]. A review of 120 cases in the literature demonstrated that 96% of patients were male, with an average age of 29 years, and 93% sustained injuries to their dominant hand [19]. In a specific study series, 100% of patients were young males, with 94% of injuries affecting the dominant hand [19].
Mechanism of Injury¶
The most common mechanism for CMC joint dislocations or fracture–dislocations of the fingers is an axial load applied to a clenched fist, such as during punching [24]. When force is applied while the metacarpal head is depressed, dislocation of the fourth and fifth CMC joints results [24]. Higher-energy injuries may produce a fracture of the base of the small finger metacarpal (reverse Bennett's fracture) or of the hamate articular surface [24]. Multiple CMC dislocations can occur and tend to be higher-energy injuries [24]. Dorsal oblique coronal hamate fractures were most commonly associated with punching (OR, 4.9; p = 0.01) [18]. Conversely, falls from height were more common in coronal splitting types of hamate fractures [18].
Physical Examination and Assessment¶
CMC dislocations and fracture–dislocations occur most often in the small and ring fingers, as well as the thumb [24]. The lack of bony constraints of the CMC joint to the ring and small fingers, in addition to the thumb, adds to their propensity for injury [24]. Inspection of the hand should look for obvious deformities and malrotation of the digits [24]. Loss of knuckle height, excessive CMC extrusion (shelf deformity for the thumb), or scissoring can alert the examiner to a CMC joint injury [24]. Pain with range of motion of the hand, tenderness to palpation about the CMC joints, or lack of ability to open and close the hand warrants radiographs [24]. The motor branch of the ulnar nerve must be evaluated given its proximity to the fifth CMC joint [24]. Multiple CMC dislocations should be identified and compartment syndrome should be considered given the significant amount of force involved and resulting hand swelling [24].
Associated Injuries¶
The most commonly associated injuries with CMC joint dislocations or fracture–dislocations include neurovascular compromise of the ulnar nerve (especially the ulnar motor branch given its proximity to the small finger CMC joint), carpal fractures (e.g., hamate fracture, trapezium fracture), concomitant metacarpal fracture, or multiple CMC dislocations or fracture–dislocations [24].
Investigations¶
Physical Examination: A careful physical examination is essential to direct care and future testing for hand and wrist injuries, as diagnostic tests such as imaging can be expensive, time-consuming, and often nonspecific [21].
Plain Radiography: Persistent palmar trapezoid dislocations following surgical treatment of second through fifth carpometacarpal fracture dislocations may be missed on standard radiographs [14].
CT: Computed tomography is required for careful evaluation of intraoperative and postoperative imaging to detect persistent palmar trapezoid dislocations that may be missed on standard radiographs [14].
Other Considerations: Delayed diagnosis of carpometacarpal fracture-dislocations makes closed reduction difficult and is associated with less favorable radiographic outcomes [9].
Treatment¶
Non-Operative¶
Undisplaced hamate fractures may be treated conservatively with good results [2]. If the diagnosis of an ulnar CMC joint dislocation or fracture–dislocation is early accomplished and a concentric and stable reduction is initially achieved, nonoperative treatment may be a successful option requiring close follow-up for the first week [11]. Timely diagnosis, adequate sedation with muscle relaxation, and gentle reduction maneuvers allowed for near-anatomic reduction of acute closed dislocations of the second through fourth CMC joints, which were adequately treated conservatively with minimal disability at 7-month follow-up [15].
Operative¶
Indications: Displaced hamate fractures or those with associated metacarpal subluxation are better treated with open reduction and internal fixation to minimize residual deformity and dysfunction [2]. In patients with delayed presentation of CMC fracture dislocations, open reduction and internal fixation is recommended [8].
Surgical Approach / Technique: Open reduction and internal fixation of the hamate body fracture with interfragmentary screws, combined with stabilization of the CMC dislocation with percutaneous Kirschner wires, showed favorable outcomes [1]. Nondisplaced or minimally displaced hamate hook fractures can be successfully treated by closed reduction and internal fixation with a headless compression screw with the assistance of robot navigation, allowing accurate fixation of small fragments with minimal iatrogenic injury [16]. Arthroscopic reduction and percutaneous fixation of fifth CMC fracture dislocations should be viewed as a useful adjunctive technique unlikely to supplant more time-tested open procedures, as long-term follow-up is unavailable [4]. Open reduction and multiple screw fixation of the hamate using a K-wire-guided technique, with supplementary Kirschner wire stabilization for associated metacarpal base fractures or CMC joint instability, was used in a study of coronal hamate body fractures with CMC instability [18].
Implant Selection: The clinically appropriate fixation method for fractures with dislocation or subluxation of the base of the fourth and fifth metacarpal bones should be selected according to the experience of the surgeon and the degree and type of fracture and dislocation [5].
Other Considerations: In a study of 35 patients with coronal hamate body fractures and CMC instability treated surgically, 34 achieved successful healing [18]. In a study of 33 patients with functional outcome data following surgical treatment of coronal hamate body fractures with CMC instability, the mean DASH score was 3.0 and mean grip strength was 94.1% of the contralateral side [18]. One patient treated 45 days post-injury for a coronal hamate body fracture with CMC instability showed recurrent subluxation and poorer outcome [18]. No differences in functional outcomes were observed between dorsal oblique and coronal splitting fracture types in a study of coronal hamate body fractures with CMC instability [18]. Excellent functional recovery and union rates were observed following surgical fixation of coronal plane hamate fractures, primarily using a single screw and K-wire stabilization [19]. Five years and two months postoperatively, radiographs showed anatomical positioning of the metacarpals and no degenerative arthritis of the carpometacarpal joints in a case of open reduction and internal fixation of multiple carpometacarpal dislocation using one plate [12]. Careful evaluation of intraoperative and postoperative imaging, particularly CT, is important to detect rare persistent palmar trapezoid dislocations that may be missed on standard radiographs following surgical treatment of second through fifth CMC fracture dislocation [14]. The superiority of any treatment strategy for fracture-dislocations of the little finger carpometacarpal joint cannot presently be determined, and higher quality comparative data is urgently needed [17].
Complications¶
Instability: Delayed presentation of carpometacarpal fracture dislocations warrants open reduction and internal fixation [8]. In one case involving a coronal hamate body fracture treated 45 days post-injury, the patient exhibited recurrent subluxation and a poorer outcome [18].
Nerve palsy: Dorsal drilling for coronal hamate fractures is considered safe because volar drill tips remain well away from ulnar nerve motor and sensory branches [13].
Other Considerations: Persistent palmar trapezoid dislocations following surgical treatment of second through fifth carpometacarpal fracture dislocations may be missed on standard radiographs and require CT for detection [14]. Arthroscopic reduction and percutaneous fixation of fifth carpometacarpal fracture dislocations lacks long-term follow-up data and is viewed as an adjunctive technique unlikely to supplant open procedures [4]. The superiority of any treatment strategy for little finger carpometacarpal joint fracture-dislocations cannot presently be determined due to a lack of higher quality comparative data [17].
Recovery¶
Non-Operative Management: Timely diagnosis, adequate sedation with muscle relaxation, and gentle reduction maneuvers facilitate near-anatomic reduction of the fracture dislocation. This approach allows for adequate conservative treatment, resulting in minimal disability at 7-month follow-up [15].
Operative Management: Open reduction and internal fixation of the hamate body fracture with interfragmentary screws, combined with stabilization of the CMC dislocation using percutaneous Kirschner wires, yields favorable outcomes [1]. Despite relatively high surgical complication rates, operative management of CMC fracture dislocations results in good-to-excellent functional outcomes [3]. In patients with delayed presentation of CMC fracture dislocations, ORIF is recommended [8]. Surgical treatment using a suture button implant permits early motion from 2 weeks after surgery, which results in good motion of the ulnar CMC joints and increased hand grip [10]. Nondisplaced or minimally displaced hamate hook fractures can be successfully treated by closed reduction and internal fixation with a headless compression screw with the assistance of robot navigation; this technique allows the small fragment of fracture to be accurately fixed with minimal iatrogenic injury [16]. Arthroscopic reduction and percutaneous fixation should be viewed as a useful adjunctive technique unlikely to supplant more time-tested open procedures, as long-term follow-up is unavailable [4].
Outcomes and Complications: Five years and two months postoperatively, radiographs showed anatomical positioning of the metacarpals and degenerative arthritis of the carpometacarpal joints was not observed [12].
Key Evidence¶
- [Paper] The study showed favorable outcomes after open reduction and internal fixation of the hamate body fracture with interfragmentary screws, when combined with stabilization of the CMC dislocation with percutaneous Kirschner wires. [1] (10.1055/s-0039-1692326)
- [L4] Undisplaced fractures may be treated conservatively with good results, while displaced fractures or those with associated metacarpal subluxation are better treated with open reduction and internal fixation to minimize residual deformity and dysfunction. [2] (10.1177/1753193408098907)
- [L4] Despite relatively high surgical complication rates, operative management of CMC fracture dislocations results in good-to-excellent functional outcomes. [3] (10.1016/j.jhsg.2024.11.003)
- [Paper] Long-term follow-up is unavailable, so the procedure should be viewed as a useful adjunctive technique unlikely to supplant more time-tested open procedures. [4] (10.1016/j.hcl.2011.05.010)
- [L2] The clinically appropriate fixation method should be selected according to the experience of the surgeon and the degree and type of fracture and dislocation. [5] (10.1186/s13018-023-04225-2)
- [Case_report] Dorsal buttress plating between the hamate and the capitate could be an alternative technique for the treatment of fracture-dislocation of the fifth CMC joint with avulsion fracture of the hamate. [6] (10.1007/s00402-018-3072-0)
- [L4] Operative treatment with headless compression screws is a safe procedure with good clinical outcomes for acute dislocated hamate corpus fractures and nondisplaced fractures of the hook of the hamate bone. [7] (10.1055/s-0039-1695765)
- [L4] In patients with delayed presentation of CMC fracture dislocations, we recommend ORIF. [8] (10.1016/j.jhsa.2015.07.017)
- [L4] Delayed diagnosis makes closed reduction difficult and was associated with less favorable radiographic outcome. [9] (10.1177/1558944719852743)
- [L4] The surgical treatment using a suture button implant allowed early motion from 2 weeks after surgery, which resulted in good motion of the ulnar CMC joints and increased hand grip. [10] (10.1055/s-0039-1693051)
- [L4] If the diagnosis of an ulnar CMC joint dislocation or fracture–dislocation is early accomplished and a concentric and stable reduction is initially achieved, the nonoperative treatment may be a successful option to take into account but requiring a close follow-up for the first week. [11] (10.1055/s-0039-1688468)
- [L5] Five years and two months postoperatively, radiographs showed anatomical positioning of the metacarpals and degenerative arthritis of the carpometacarpal joints was not observed. [12] (10.1016/s0020-1383(97)82145-6)
- [L5] Dorsal drilling of coronal hamate fractures appears to be safe, as volar drill tips are well away from ulnar nerve motor and sensory branches. [13] (10.1016/j.jhsa.2022.04.023)
- [L4] This report highlights the importance of careful evaluation of intraoperative and postoperative imaging, particularly CT, to detect rare persistent palmar trapezoid dislocations that may be missed on standard radiographs. [14] (10.1016/j.jhsg.2025.100769)
- [L4] Timely diagnosis, adequate sedation with muscle relaxation, and gentle reduction maneuvers allowed for near-anatomic reduction of the fracture dislocation, which was adequately treated conservatively with minimal disability at 7-month follow-up. [15] (10.1007/s11552-012-9484-3)
- [L4] Nondisplaced or minimally displaced hamate hook fractures can be successfully treated by closed reduction and internal fixation with a headless compression screw with the assistance of robot navigation, and the small fragment of fracture can be accurately fixed with minimal iatrogenic injury. [16] (10.1186/s12891-023-06917-6)
- [L2] The superiority of any treatment strategy cannot presently be determined, and higher quality comparative data is urgently needed. [17] (10.1177/1753193417752317)
- [Paper] [18] (10.1007/s00402-026-06366-5)
- [Paper] [19] (10.52312/jdrs.2025.1997)
- [Paper] [20] (10.3205/iprs000131)
See Also¶
References¶
[1] Carpometacarpal 4/5 Fracture Dislocations: Fracture Morphology and Surgical Treatment. Journal of Hand and Microsurgery. 2020. DOI: 10.1055/s-0039-1692326
[2] Outcome following coronal fractures of the hamate. Journal of Hand Surgery (European Volume). 2009. DOI: 10.1177/1753193408098907
[3] Operative Treatment of Non-Thumb Carpometacarpal Joint Fracture Dislocations. Journal of Hand Surgery Global Online. 2025. DOI: 10.1016/j.jhsg.2024.11.003
[4] Arthroscopic Reduction and Percutaneous Fixation of Fifth Carpometacarpal Fracture Dislocations. Hand Clinics. 2011. DOI: 10.1016/j.hcl.2011.05.010
[5] A comparative study on the clinical efficacy of microplate trans-carpometacarpal joint fixation and non-trans-carpometacarpal joint fixation in treating fractures with dislocation or subluxation of the base of the fourth and fifth metacarpal bones. Journal of Orthopaedic Surgery and Research. 2023. DOI: 10.1186/s13018-023-04225-2
[6] Dorsal buttress plate fixation for the treatment of fracture–dislocation of the fifth carpometacarpal joint with avulsion fracture of the hamate: a case report. Archives of Orthopaedic and Trauma Surgery. 2018. DOI: 10.1007/s00402-018-3072-0
[7] Functional Outcome following Headless Compression Screw Fixation for Hamate Fractures. Journal of Wrist Surgery. 2019. DOI: 10.1055/s-0039-1695765
[8] The Effect of Timing on the Treatment and Outcome of Combined Fourth and Fifth Carpometacarpal Fracture Dislocations. The Journal of Hand Surgery. 2015. DOI: 10.1016/j.jhsa.2015.07.017
[9] Carpometacarpal Fracture-Dislocations: A Retrospective Review of Injury Characteristics and Radiographic Outcomes. HAND. 2019. DOI: 10.1177/1558944719852743
[10] Surgical Treatment for Delayed Ulnar Carpometacarpal Fracture–Dislocations. Journal of Wrist Surgery. 2019. DOI: 10.1055/s-0039-1693051
[11] Nonoperative Treatment of Ulnar Carpometacarpal Fracture–Dislocations. Journal of Wrist Surgery. 2019. DOI: 10.1055/s-0039-1688468
[12] Open reduction and internal fixation of an unusual multiple carpometacarpal dislocation using one plate: a case report. Injury. 1997. DOI: 10.1016/s0020-1383(97)82145-6
[13] Dorsal Fixation of Coronal Hamate and Fifth Metacarpal Base Fractures: An Anatomic Evaluation of the Ulnar Nerve. The Journal of Hand Surgery. 2024. DOI: 10.1016/j.jhsa.2022.04.023
[14] Diagnosis and Management of Persistent Trapezoid Dislocation Following Surgical Treatment of Second through Fifth Carpometacarpal Fracture Dislocation. Journal of Hand Surgery Global Online. 2025. DOI: 10.1016/j.jhsg.2025.100769
[15] Acute Closed Dislocation of the Second through Fourth Carpometacarpal Joints: Satisfactory Treatment with Closed Reduction and Immobilization. HAND. 2013. DOI: 10.1007/s11552-012-9484-3
[16] Minimally invasive percutaneous screw internal fixation under robot navigation for the treatment of a hamate bone fracture. BMC Musculoskeletal Disorders. 2023. DOI: 10.1186/s12891-023-06917-6
[17] Management of fracture-dislocations of the little finger carpometacarpal joint: a systematic review. Journal of Hand Surgery (European Volume). 2018. DOI: 10.1177/1753193417752317
[18] Coronal hamate body fractures with dorsal fourth and fifth carpometacarpal joint instability: fracture patterns, injury mechanisms, surgical strategies, and outcomes. Archives of Orthopaedic and Trauma Surgery. 2026. DOI: 10.1007/s00402-026-06366-5
[19] Surgical treatment of coronal plane hamate fractures: Clinical and radiological outcomes. Joint Diseases and Related Surgery. 2024. DOI: 10.52312/jdrs.2025.1997
[20] Hamate’s coronal fracture: diagnostic and therapeutic approaches based on a long-term follow-up. GMS Interdisciplinary Plastic and Reconstructive Surgery DGPW; 8:Doc05. 2019. DOI: 10.3205/iprs000131
[21] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Anatomy, Evaluation, Clinical Examination, and Imaging > Evaluation and Clinical Examination: Current Concepts.
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[24] Rockwood And Green S Fractures In Adults. 42: Fractures of the Distal Radius and Ulna > Carpometacarpal Joint Dislocations.
[27] Green S Operative Hand Surgery. Interosseous and Hypothenar Muscles.
[30] Exam Of The Hand Wrist 2Ed. The arches of the hand > The metacarpal arch.