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Hamate and CMC Fracture-Dislocation Fixation

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Overview¶
Hamate and carpometacarpal (CMC) fracture-dislocations present a spectrum of injuries where treatment selection depends on displacement, associated subluxation, and timing of diagnosis. Undisplaced hamate fractures may be managed conservatively with good results [2], whereas displaced fractures or those with associated metacarpal subluxation require open reduction and internal fixation to minimize residual deformity and dysfunction [2]. For CMC fracture dislocations, operative management yields good-to-excellent functional outcomes despite relatively high surgical complication rates [3]. However, the superiority of any specific treatment strategy for little finger CMC fracture-dislocations cannot presently be determined, and higher quality comparative data is urgently needed [17]. Consequently, the clinically appropriate fixation method should be selected according to the surgeon’s experience and the degree and type of fracture and dislocation [5].
Operative techniques vary based on fracture location and stability. Favorable outcomes have been demonstrated using interfragmentary screws for hamate body fractures combined with percutaneous Kirschner wires for CMC dislocation stabilization [1]. Headless compression screws are a safe option for acute dislocated hamate corpus fractures and nondisplaced hook fractures [7], with robot navigation assisting in closed reduction and fixation for nondisplaced or minimally displaced hook fractures [16]. Alternative techniques include dorsal buttress plating between the hamate and capitate for fifth CMC avulsion fracture-dislocations [6] and suture button implants, which allow early motion from two weeks postoperatively [10]. Arthroscopic reduction and percutaneous fixation serve as a useful adjunctive technique, though long-term follow-up is unavailable [4]. Dorsal drilling of coronal hamate fractures is considered safe, as volar drill tips remain well away from ulnar nerve branches [13].
Non-operative management is viable 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, and gentle reduction maneuvers allow for near-anatomic reduction of acute closed dislocations of the second through fourth CMC joints, resulting in minimal disability at seven-month follow-up [15]. In cases of delayed presentation, open reduction and internal fixation is recommended [8], as delayed diagnosis makes closed reduction difficult and is associated with less favorable radiographic outcomes [9]. Careful evaluation of intraoperative and postoperative imaging, particularly CT, is essential to detect rare persistent palmar trapezoid dislocations that may be missed on standard radiographs [14]. Long-term follow-up in multiple CMC dislocations treated with a single plate has shown anatomical metacarpal positioning without degenerative arthritis at five years and two months postoperatively [12].
Anatomy & Pathophysiology¶
Bony Anatomy and Kinematics¶
The hand skeleton comprises 27 bones, 19 of which are long bones [23]. Each metacarpal base articulates with the distal carpal row [23]. The wrist possesses three axes of movement, allowing the hand to assume any spatial configuration [23]. Kinematic stability varies across the carpometacarpal (CMC) joints: the index metacarpal is the most firmly fixed [30], while the ring metacarpal exhibits approximately 10 degrees of flexion–extension mobility [30]. The fifth metacarpal demonstrates a greater range of flexion–extension, approximately 20 degrees [30].
Soft Tissue Anatomy¶
The extensor carpi ulnaris tendon traverses the sixth dorsal compartment to insert at the base of the little finger metacarpal [22]. Intrinsic musculature of the hypothenar eminence includes the opponens digiti quinti, which arises from the pisohamate ligament and the hook of the hamate and inserts onto the ulnar side of the fifth metacarpal diaphysis [27]. The abductor digiti quinti and flexor digiti quinti brevis also originate from the fifth metacarpal [27]. The flexor digitorum profundus tendons for the ring and little fingers receive innervation from the ulnar nerve [34]. Palmar soft tissue anatomy includes the superficial palmar fascia, which covers a triangular area of the central palm with its proximal corner oriented directly proximal [37]. When present, the palmaris longus tendon terminates in continuity with the fibers of this proximal corner [37].
Injury Mechanisms and Pathophysiology¶
CMC dislocations and fracture–dislocations predominantly affect the small and ring fingers, as well as the thumb [24]. The ring and small finger CMC joints lack significant bony constraints, increasing their susceptibility to injury [24]. Conversely, the central digits are protected from deformity by the stabilizing effects of the deep transverse intermetacarpal ligaments (interglenoid ligaments) and bony constraints at the CMC joint [24]. The interglenoid ligament binds the second through fifth metacarpals and connects the anterior glenoid ligaments (volar plates) of the metacarpophalangeal articulations [30].
The primary mechanism for digital CMC dislocations or fracture–dislocations is an axial load applied to a clenched fist [24]. If force is applied while the metacarpal head is depressed, dislocation of the fourth and fifth CMC joints results [24]. Higher-energy impacts may cause fractures of the small finger metacarpal base or the hamate articular surface [24]. Multiple CMC dislocations indicate higher-energy trauma and carry a worse prognosis due to the magnitude of force imparted to the hand [24].
Hamate fractures account for 2–4% of all carpal fractures [20]. Hamate-metacarpal fracture-dislocations represent 10–15% of carpometacarpal region fracture-dislocations [20]. Hamate body fractures predominantly occur in the dominant arm of young adult males [19]. A review of 120 cases identified that 96% of patients were male, with an average age of 29 years, and 93% sustained injuries to their dominant hand [19]. The most common mechanisms for hamate body fractures are striking a solid object with a clenched fist (52%) and falls (22%) [19].
Regarding fracture morphology, dorsal oblique coronal hamate body fractures occur more frequently than coronal splitting fractures (63.8% vs 36.2%) [18]. Dorsal oblique coronal fractures are most commonly associated with punching (OR, 4.9; p = 0.01) [18], whereas falls from height are more common in coronal splitting types [18]. Concomitant fractures occur in 82.8% of cases involving coronal hamate body fractures with CMC instability, most frequently affecting the fourth metacarpal base [18].
Neurovascular compromise, particularly of the ulnar motor branch, is a common associated injury with CMC joint dislocations or fracture–dislocations [24]. The motor branch of the ulnar nerve must be evaluated given its proximity to the fifth CMC joint [24].
Classification¶
Milch: The first classification of hamate fractures was established by Milch et al. in 1934 and does not include coronal fractures [20].
Cain: Cain’s classification focuses on the dislocation of the fifth CMC and further co-fractures of the hamate [20].
Ebraheim: Ebraheim’s classification focuses on the course of the fracture line through the hamate body [20]. Ebraheim’s variant of subdivision was used for preoperative planning in a study of coronal hamate fractures because it was hypothesized to deliver the best information necessary for treatment considerations [20].
Other Considerations: Hamate fractures are generally subdivided into hook fractures and fractures of the hamate body [20]. Coronal hamate body fractures are classified as dorsal oblique or coronal splitting types based on computed tomography findings [18]. Dorsal oblique fractures occurred more frequently than coronal splitting fractures in a retrospective review of 58 patients [18]. Dorsal oblique fractures were most commonly associated with punching injuries, while falls from height were more common in coronal splitting types [18]. The limitations of existing classification systems must be taken into account when individualizing treatment for carpometacarpal fracture-dislocations associated with hamate fractures [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]. Demographic data indicate a strong male predominance; a review of 120 cases reported 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 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 are associated with higher-energy mechanisms [24]. For hamate body fractures, the most common reported mechanisms 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 (OR, 4.9; p = 0.01) [18], whereas falls from height are 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 at the CMC joints of the ring and small fingers, in addition to the thumb, contributes to their propensity for injury [24]. Inspection of the hand should identify obvious deformities and malrotation of the digits [24]. Clinical signs alerting the examiner to a CMC joint injury include loss of knuckle height, excessive CMC extrusion (shelf deformity for the thumb), or scissoring [24]. Pain with range of motion of the hand, tenderness to palpation about the CMC joints, or an inability to open and close the hand warrants radiographs [24]. Given the significant force involved and resulting hand swelling, multiple CMC dislocations should be identified and compartment syndrome should be considered [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, such as hamate or trapezium fractures * Concomitant metacarpal fracture * Multiple CMC dislocations or fracture–dislocations [24]
Investigations¶
Other Considerations: Delayed diagnosis of carpometacarpal fracture-dislocations renders closed reduction difficult and is associated with less favorable radiographic outcomes [9]. A careful physical examination is essential to direct care and future testing if indicated [21].
Treatment¶
Non-Operative Management¶
The provided evidence does not detail specific conservative management protocols, such as weight loss, physical therapy, NSAIDs, or injections, for hamate and CMC fracture-dislocations.
Operative Management¶
Indications: The superiority of any treatment strategy for little finger CMC joint fracture-dislocations cannot presently be determined, and higher quality comparative data is urgently needed [17].
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]. For nondisplaced or minimally displaced hamate hook fractures, closed reduction and internal fixation with a headless compression screw assisted by robot navigation allows 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 due to unavailable long-term follow-up [4]. Surgical fixation of coronal hamate body fractures with CMC instability, primarily using a single screw and K-wire stabilization, observed excellent functional recovery and union rates [19]. 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, resulted in successful healing in 34 of 35 patients with a minimum 6-month follow-up [18].
Implant Selection: In a retrospective review of 58 patients with coronal hamate body fractures and CMC instability, the mean DASH score was 3.0 and mean grip strength was 94.1% of the contralateral side among those with functional outcome data [18]. One patient treated 45 days post-injury for a coronal hamate body fracture showed recurrent subluxation and poorer outcome [18]. Five years and two months postoperatively, radiographs of a patient treated with open reduction and internal fixation using one plate for multiple CMC dislocations showed anatomical positioning of the metacarpals and no degenerative arthritis of the carpometacarpal joints [12].
Other Considerations: 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 dislocations [14].
Complications¶
Instability: Delayed presentation of carpometacarpal fracture dislocations necessitates open reduction and internal fixation [8]. In one case of a coronal hamate body fracture treated 45 days post-injury, the patient experienced recurrent subluxation and a poorer outcome [18]. 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].
Nerve palsy: Dorsal drilling for coronal hamate fractures is considered safe because volar drill tips are well away from ulnar nerve motor and sensory branches [13].
Other Considerations: Operative management of non-thumb carpometacarpal joint fracture dislocations is associated with relatively high surgical complication rates [3]. 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].
Recovery¶
Operative Management: Displaced fractures or those with associated metacarpal subluxation are better treated with open reduction and internal fixation to minimize residual deformity and dysfunction [2]. For ulnar CMC joints, 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]. In cases of nondisplaced or minimally displaced hamate hook fractures, closed reduction and internal fixation with a headless compression screw with the assistance of robot navigation allows the small fragment of fracture to be accurately fixed with minimal iatrogenic injury [16]. Long-term radiographic assessment five years and two months postoperatively showed anatomical positioning of the metacarpals and no observation of degenerative arthritis of the carpometacarpal joints [12].
Non-Operative Management: Undisplaced 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 to take into account, but it requires a 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 the fracture dislocation, which was adequately treated conservatively with minimal disability at 7-month follow-up [15].
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
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