Ultrasound of the Hook of Hamate Region: Pictorial Review.

The hook of hamate is a complex anatomical region with many small but important structures. A sound knowledge of anatomy along with a systematic ultrasound technique can help delineate a variety of disorders. In this pictorial review, we discuss the ultrasound anatomy and the possible pathologies that can be encountered in this region.

Minimally invasive percutaneous screw internal fixation under robot navigation for the treatment of a hamate bone fracture.

PURPOSE: Hamate fractures are rare fractures of the wrist and there is still no consensus on the optimal treatment for these fractures, especially hook of hamate fractures. Herein, the authors present a case study of a series of patients who were treated with closed reduction and minimally invasive percutaneous fixation under robot navigation. METHODS: This retrospective study reviewed 14 patients who had nondisplaced or minimally displaced hamate fractures on computerized tomography images and were treated using the treatment in our centre from November 1, 2019, to October 31, 2022. At the final follow-up, the flexion-extension and radial-ulnar range of motion of the wrist were measured, and the grip strength and pinch strength were measured. The pain of the wrist was assessed using the visual analogue scale (VAS). The Mayo wrist score reflected the recovery of the wrist. RESULTS: The mean total operative duration was 40.1 min. All the fractures showed union at a mean of 3.0 months. At a mean follow-up of 23.3 months (range 6-36 months), the mean VAS score was 0.7, the average Mayo wrist score was 95, and the mean pinch strength and grip strength were 11.3 and 38.7 kg, respectively. The flexion-extension arc was 138.3°, the mean radial and ulnar deviation arc was 63.8°, and the mean pronation-supination arc was 172.3°. And the time of return to the original occupation was mean 4 months (3~6 months). There were no complications, such as infection or nerve paralysis. CONCLUSIONS: This study suggests that 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.

Bennett fracture combined with hamate fracture: carpometacarpal joint 'diagonal' fracture and dislocation: a case report.

BACKGROUND: Multiple carpometacarpal fractures and dislocations are rare. This case report describes a novel multiple carpometacarpal injury, namely, 'diagonal' carpometacarpal joint fracture and dislocation. CASE PRESENTATION: A 39-year-old male general worker sustained a compression injury to his right hand in the dorsiflexion position. Radiography indicated a Bennett fracture, hamate fracture, and fracture at the base of the second metacarpal. Subsequent computed tomography and intraoperative examination confirmed an injury to the first to fourth carpometacarpal joint along a diagonal line. The normal anatomy of the patient's hand was successfully restored via open reduction combined with Kirschner wire and steel plate fixation. CONCLUSION: Our findings highlight the importance of taking the injury mechanism into account to avoid a missed diagnosis and to choose the best treatment approach. This is the first case of 'diagonal' carpometacarpal joint fracture and dislocation to be reported in the literature.

Retrospective interobserver agreement on diagnoses of 4th and 5th carpometacarpal fracture-dislocation and hamate fracture in plain X-ray - Is CT essential after ulnar carpometacarpal pain?

OBJECTIVE: To determine interobserver agreement and reliability of different radiological parameters in the assessment of fracture-dislocation of the 4th and 5th carpometacarpal joints (FD CMC 4-5) and associated hamate fracture on radiographs. MATERIALS AND METHODS: A retrospective, consecutive case series of 53 patients diagnosed with FD CMC 4-5. Emergency room diagnostic radiology images were reviewed by four independent observers. The reviews included assessment of radiological patterns and parameters in relation to CMC fracture-dislocations and associated injuries previously described in the literature, to analyze their diagnostic power (specificity and sensitivity) and reproducibility (interobserver reliability). RESULTS: Among 53 patients, mean age 35.3 years, dislocation of the 5th CMC joint was present in 32/53 (60%) of patients, mostly (11/32 [34%]) associated with 4th CMC dislocation and base of 4th and 5th metacarpal fracture. The most common presentation of hamate fracture, in 4/18 (22%), was associated with combined 4th and 5th CMC dislocation and base of metacarpal fracture. Computed tomography (CT) was performed in 23 patients. Performing CT scan was significantly associated with hamate fracture diagnosis (p < 0.001). Interobserver agreement was slight (0-0.641) for most of the parameters and diagnoses. Sensitivity ranged from 0 to 0.61. Overall, the described parameters had low sensitivity. CONCLUSION: Radiological parameters described for assessment of fracture-dislocation of the 4th and 5th CMC joints and associated hamate fracture have a slight interobserver agreement index in plain X-ray and low sensitivity for diagnostic assessment. These results suggest the need for emergency medicine diagnostic protocols that include CT scan for such injuries. GOV IDENTIFIER: NCT04668794.

Reverse Hemi-Hamate Autograft for Volar Proximal Interphalangeal Joint Fracture-Dislocations.

Volar proximal interphalangeal joint fracture-dislocations are rare injuries. Treatment is challenging when they are not identified acutely, with poor outcomes reported. We report a surgical technique to treat chronic volar proximal interphalangeal joint fracture-dislocations: a reverse hemi-hamate autograft.

Medial femoral condyle free flap for carpo-metacarpal instability following hamate comminute fracture.

Complete reconstruction of the hamate bone has been reported in the literature mostly following cancer excision or avascular necrosis. For the exiguity of the tissue deficit, bone grafting has usually been used as treatment option for its rapidity and easiness to perform, even if a variable amount of bone resorption may occur. In traumatic cases, microbial contamination may jeopardize the success of a well performed bone graft and vascularised bone grafts may represent a better reconstructive option. Here we describe the first case reported in the literature of a patient underwent complete hamate reconstruction following trauma with an osseous medial femoral condyle free flap as vascularized arthrodesis between the capitate and the 4th MTC base, in order to stabilize the 4th and 5th finger and the ulnar carpo-metacarpal joint.

Dorsal Fixation of Coronal Hamate and Fifth Metacarpal Base Fractures: An Anatomic Evaluation of the Ulnar Nerve.

PURPOSE: Traumatic drill overshoot during dorsal fixation of coronal hamate and fifth metacarpal base fractures risks iatrogenic ulnar nerve injury. This study describes the anatomic relationships between exiting volar drill tips and ulnar nerve branches. METHODS: Dorsal drilling of hamate bones and fifth metacarpal bases was performed on cadavers. Dorsal hamate bodies were subdivided into 4 quadrants: (1) distal-ulnar, (2) distal-radial, (3) proximal-ulnar, and (4) proximal-radial. Screws measuring 5 mm more than the dorsal-to-volar bone depths were placed in each quadrant to represent drill exit trajectories with consistent overshoot. A single screw was similarly placed 5 mm distal to the midline articular surface of the dorsal fifth metacarpal base. Distances between estimated drill tips and ulnar nerve branches were measured. RESULTS: Ten cadaver hands were examined. The fifth metacarpal base screw tips directly abutted the ulnar motor branch in 6 hands, and were within 1 mm in 4 hands (mean, 0.4 ± 0.5 mm). Distances from the tips to the ulnar motor and sensory branches were largest in the distal-radial quadrant (11.8 ± 0.8 mm and 9.2 ± 1.9 mm, respectively) and smallest in the proximal-ulnar quadrant (7.3 ± 1.5 mm and 4.3 ± 1.1 mm, respectively). Distances to the ulnar motor and sensory branches were similar between the proximal-ulnar and distal-ulnar quadrants, and between the proximal-radial and distal-radial quadrants. CONCLUSIONS: Dorsal drilling of coronal hamate fractures appears to be safe, as volar drill tips are well away from ulnar nerve motor and sensory branches. Distances to ulnar nerve branches are largest, and theoretically safest, with dorsal drilling in the distal-radial hamate. Dorsal drilling of fifth metacarpal base fractures appears to carry a high risk for potential ulnar motor nerve injury. CLINICAL RELEVANCE: These findings may help minimize potential risks for iatrogenic ulnar nerve injury with dorsal drilling of hamate and fifth metacarpal base fractures.

Upper Extremity Injuries in Rock Climbers: Diagnosis and Management.

Rock climbing places substantial stress on the upper extremities and can lead to unique injuries not common to other sports. With increasing popularity of the sport, hand surgeons are expected to see more patients with these pathologies. An understanding of the sport, accurate diagnoses, and appropriate treatment protocols are critical to maintain climbers' competitive abilities.

Hook of Hamate Fractures in Major and Minor League Baseball Players.

PURPOSE: The purpose of this study was to describe an approach to surgical management of the hook of hamate fractures in professional baseball players. METHODS: A retrospective chart review was performed on Major and Minor League Baseball players who underwent surgical excision for the hook of hamate fracture between the years 2003 and 2019 by a single surgeon. Patient demographics, the mechanism and timing of the injury, diagnostic and operative details, postoperative complications, and timeline to return to baseball activities were recorded. RESULTS: A total of 145 professional baseball players affiliated with 17 Major League Baseball organizations were studied, with the majority of athletes playing at the Minor League Baseball level (91.7%). Subacute or chronic patterns of injury (81.7%) were found to be more common than acute patterns based on radiographic and intraoperative findings. Two patients reported transient numbness in the fourth and fifth digits after surgery, 6 patients reported pisotriquetral pain when returning to a hitting program, and 1 patient developed heterotopic ossification after surgery. All complications resolved during a strength and conditioning program. On average, players in our cohort began a hitting program at 4.6 weeks after surgery and were released into full baseball activities at 7.1 weeks after surgery. CONCLUSIONS: Surgical excision remains an effective method of management, with a low risk of minor complications for both acute and chronic hook of hamate fractures in professional baseball players. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic Level IV.

Atypical osteochondroma of the hamate that presented clinically as carpal tunnel syndrome: report of an extremely rare case and literature review.

BACKGROUND: Osteochondroma is a benign tumor that occurs mainly at the metaphysis of long bones and seldom arises from carpal bones. We describe an extremely rare case of osteochondroma of the hamate without a typical cartilaginous cap and with a spiky bony protrusion in an elderly patient. CASE PRESENTATION: A 78-year-old right-handed female housekeeper had a multilobed osteochondroma of the hamate, which caused carpal tunnel syndrome and irritation of the flexor tendons. Radiological examinations showed a morphological abnormality of the hamate comprising a spiky bony protrusion into the carpal tunnel and a free body proximal to the pisiform. Open carpal tunnel release and resection of the spiky bony protrusion on the hook of the hamate were performed. The flexor digitorum profundus tendons of the ring and little fingers displayed synovitis and partial laceration in the carpal tunnel. Histological examination also showed atypical findings: only a few regions of cartilaginous tissue were seen in the spiky bony protrusion, whereas the free body proximal to the pisiform contained thick cartilaginous tissue such as a cartilaginous cap typical of osteochondroma. We speculated that the bony protrusion to the carpal tunnel had been eroded by mechanical irritation caused by gliding of the flexor tendon and had resulted in the protruding spiky shape with less cartilaginous tissue. The fractured cartilaginous cap had moved into the cavity within the carpal tunnel proximal to the pisiform and had become a large free body. CONCLUSIONS: Osteochondroma of the carpal bone may take various shapes because the carpal bone is surrounded by neighboring bones and tight ligaments, which can restrict tumor growth. This type of tumor is likely to present with various symptoms because of the close proximity of important structures including nerves, tendons, and joints. The diagnosis of osteochondroma of the carpal bone may be difficult because of its rarity and atypical radiological and histological findings, such as the lack of a round cartilaginous cap. We suggest that surgeons should have a detailed understanding of this condition and should make a definitive diagnosis based on the overall findings.

An Analysis of Hamate Morphology Relevant to Hemi-Hamate Arthroplasty.

PURPOSE: Dorsal fracture-dislocations of the proximal interphalangeal (PIP) joint can lead to joint incongruity from loss of the buttress function of the middle phalanx volar base. Hemi-hamate arthroplasty can reconstruct the volar articular surface of the middle phalangeal base where repair is not possible. We compared the anatomy of the hamate graft with the middle phalanx base. METHODS: Forty unique skeletal specimens (40 hamates, 160 middle phalanges) were sampled. Anatomical features relevant to hemi-hamate reconstruction were measured, including the articular surface areas, the axial ridge angles, and the sagittal inclination angles of the hamate and the middle phalanx base specimens. Facets of the articular surfaces were classified as concave, convex, or flat. Calibrated measurements were made using digital photographs of the cadaveric specimens. Descriptive and univariate statistics were performed. RESULTS: There was greater variability in the distal hamate than in the middle phalanx base. The ring finger facet of the distal hamate was concave in 39 of 40 specimens, whereas the little finger facet was convex in 31 of 40 specimens. The hamate axial ridge angle (66.0° ± 3.7°) was significantly different from the middle phalanx base (90.4° ± 0.4°). The hamate articular sagittal inclination (3.2° ± 4.1°) was significantly different from the middle phalanx base (51.2° ± 1.3°). The hamate articular surface area (1.96 cm2) was significantly greater than the middle phalanx base (mean index/middle/ring finger = 0.85 cm2 and mean little finger = 0.59 cm2). CONCLUSIONS: The distal articular surface of the hamate is not anatomically identical to the middle phalanx base. The differences may still preclude anatomical reconstruction in the setting of a dorsal PIP fracture-dislocation, thereby affecting short- and long-term outcomes. CLINICAL RELEVANCE: Knowledge of the anatomical differences between the distal hamate and the middle phalanx base may improve graft harvest and inset during reconstruction.

Topographical Analysis of the Hamate for Proximal Pole Scaphoid Nonunion Reconstruction.

PURPOSE: To quantify the similarity of the surface topography of the proximal hamate and proximal pole of the scaphoid for nonunion reconstruction. METHODS: Using previously acquired computed tomographic scans of the wrist of 10 patients, the 2 bones were segmented and subsequently aligned using both a manual and automated technique. Surface error between corresponding articular surfaces was computed to determine the similarity of the shape of the 2 bones. RESULTS: The median distance between the 2 articulating surfaces for each patient was 1 mm or less for all cases. Maximum distance varied from 2.7 to 9.7 mm. The automated method improved alignment such that the maximum distance was 4.1 mm. Visual review of the alignment revealed that the maximum error occurred on or around the margin of the articulating surfaces. CONCLUSIONS: In most cases, the proximal hamate appears to be a suitable donor match to reconstruct proximal pole scaphoid nonunions. CLINICAL RELEVANCE: This study serves as a guide to practitioners when considering the suitability of the proximal hamate autograft for unsalvageable proximal pole scaphoid nonunions.

Non-vascularized partial joint transfer for Finger Proximal Interphalangeal joint reconstruction: a series of 9 patients.

INTRODUCTION: Finger proximal interphalangeal joint (PIP) reconstruction after the destruction of parts of the joint remains challenging. Surgical techniques include implant arthroplasty, arthrodesis, free vascularized joint transfer, and non-vascularized bone and joint transfer. This study analyzes our experience after non-vascularized transfer in terms of range of motion, postoperative rehabilitation, and patient satisfaction. MATERIALS AND METHODS: Between 2009 and 2014, ten patients underwent non-vascularized partial joint transfer for PIP joint reconstruction. One of them was lost to follow-up. Included patients had osteochondral partial joint transplants of 25-50% of the toes (n = 4) and the hand (n = 5). Range of motion (ROM), grip-, and pinch-strength were measured at the last follow-up control and compared to the healthy side. Patients were asked to score the pain at rest/ on load on a visual scale (VAS: 0 = no pain; 10 = excruciating pain). Satisfaction self-assessment was evaluated by asking the patients to grade their postoperative result as excellent, very good, good or poor. RESULTS: Mean follow-up period was 4.0 years (range 1.2-7.9 years). Mean PIP joint flexion was 93 ± 26° at the last follow-up control. Mean grip- and pinch-strength of the operated side at the last control were, respectively, 43 ± 18 kg and 8 ± 5 kg, close to the healthy side values (45 ± 15 kg and 9 ± 4 kg). Mean pain at rest/on load measured on a visual scale was, respectively, 0.3 ± 1 and 1.8 ± 2. Eight patients (89%) rated their operation as excellent, and one as poor. CONCLUSION: In this study, non-vascularized partial joint transfer provides a mobile and stable PIP joint 4 years after reconstruction. The surgical technique presented herein is complex depending on additional injuries but results in great patient satisfaction.

Radiographic prediction of lunate morphology in Asians using plain radiographic and capitate-triquetrum distance analyses: reliability and compatibility with magnetic resonance arthrography (MRA) findings.

BACKGROUND: The purpose of this study was to examine the reliability of plain radiographic methods of determining the lunate type and its compatibility with magnetic resonance arthrography (MRA) findings. METHODS: Plain radiographs of a total of 150 wrists were reviewed by three observers. Lunate types were evaluated using both conventional posteroanterior (PA) radiographic analysis and the capitate-triquetrum distance (CTD) analysis. Cohen kappa and Fleiss kappa statistics were used to estimate intra- and inter-observer reliabilities. Compatibility with the MRA findings, as assessed by each observer, was investigated. RESULTS: The overall intra-observer reliability was 0.517 for the analysis and 0.589 for the CTD analysis. The overall inter-observer agreement was 0.448 for the PA radiographic analysis and 0.581 for the CTD analysis. The PA radiographic analysis and MRA findings for the detection of medial lunate facets were compatible in 119 of the 150 patients (79.3%). Twenty-eight (90.3%) of the 31 incompatible wrists had a medial facet on MRA (Type II), which was not detected in the PA radiographic analysis. In the CTD analysis, the results for 27 of 29 Type II lunates (93.1%) and 39 of 45 Type I lunates (86.7%) were compatible with the MRA. CONCLUSIONS: This study suggests that predicting the lunate type by plain radiographs alone is insufficient, as both radiographic analyses showed moderate intra- and inter-observer reliabilities. Although both radiographic analyses showed good compatibility with the MRA for Type II lunates, clinicians should be alert to undetected medial facets in Type I lunates on PA radiographic analysis.

Radiographic signs of hook of hamate fracture: evaluation of diagnostic utility.

OBJECTIVE: Hook of hamate fracture, the most common swing-related wrist fracture, is commonly seen in high-level athletes. The fracture is rarely diagnosed on routine wrist radiographs, thus generally requiring CT or MR for diagnosis. Surgical excision has a high success rate, however diagnostic delay contributes to a high complication rate. Radiographic signs of hook of hamate fracture have been published, but uncertainty of the diagnostic accuracy limits application. The purpose of this study is to determine accuracy and interobserver reliability of radiographic signs of hook of hamate. MATERIALS AND METHODS: This retrospective case-control study evaluated wrist radiographs of 50 patients, including 24 positive and 26 negative, for hook of hamate fracture, each proven by CT or MR. Five reviewers performed blinded, randomized evaluation of radiographs documenting whether the hook of hamate was normal or fractured, and if fractured, the radiographic signs present (ring sign, ghostly shadow, and diffuse sclerosis) and views that contributed to diagnosis. RESULTS: Radiographic signs demonstrated high sensitivity (85%; 95% CI: 77-91), specificity (92%; 95% CI: 86-96), and accuracy (89%; 95% CI: 84-92) with substantial interobserver reliability (k = 0.652). The ring sign was the most sensitive radiographic sign. Diagnosis was most often supported by the oblique view (38%) and rarely the lateral view (15%). CONCLUSIONS: Radiographic signs of hook of hamate fracture on routine radiographs can accurately and reliably diagnose hook of hamate fractures. Evaluation for discontinuity of the cortical ring will optimize sensitivity, allowing for timely diagnosis and treatment, and a reduction of complications.

Variations in Hook of Hamate Morphology: A Cadaveric Analysis.

PURPOSE: The hook of the hamate is an anatomical structure that separates the ulnar border of the carpal tunnel from Guyon's canal and serves as a landmark for surgeons. The hook of the hamate is also subject to fracture from injury. We hypothesize that there are variations in the hook of the hamate in the general population. METHODS: One thousand pairs of hamates (2,000 hamates) from the Hamann-Todd Collection at the Cleveland Natural History Museum were analyzed. The height of the hook of the hamate and the total height of the hamate bone were measured using digital calipers. The hook height ratio was defined as the hook height divided by the total height of the hamate. Statistical analysis was performed using unpaired Student's t test to determine differences in sex and race. RESULTS: The mean hook height was 9.8 ± 1.4 mm (range, 2.5-15.9 mm), whereas the mean hook height ratio was 0.42 ± 0.04 (range, 0.15-0.56). There was a 3.1% (62/2,000) incidence of abnormally small hooks, which we classified as hypoplastic and aplastic. Of the hypoplastic hooks, 55% (24/44) were bilateral, whereas 44% (8/18) of the aplastic hooks were bilateral. The incidence of variation in size in the hook of the hamate was highest in white females (9.3%) and lowest in black males (1.4%). CONCLUSIONS: Abnormalities in hook of hamate anatomy are common in the general population, especially in white females. CLINICAL RELEVANCE: Knowledge of anatomic variation in the hook of the hamate may provide additional insight into surgeons' palpation of bony anatomy, interpretation of imaging studies, and use of the hook as a landmark during surgery.

A Modified Surgical Approach Through Guyon's Canal and the Proximal Ulnar Border of the Carpal Tunnel Allows for Safe Excision of the Hook of the Hamate.

Hook of the hamate fractures can be treated by various methods including cast immobilization, open reduction, and internal fixation and excision. Usually, those individuals who elect for excision have acute fractures and need to return to sporting activity or work quickly or have nonunions with persistent symptoms. There is a paucity of descriptions in the literature and textbooks of a technique to safely excise the hook of the hamate. The authors present a method of safely exposing and removing the hook of the hamate by visualizing the potential structures at risk: the motor branch of the ulnar nerve, the ulnar digital nerve to the little finger, and the flexor tendons to the ring and little fingers by an approach through Guyon's canal and the proximal ulnar border of the carpal tunnel.

Minimally Invasive Fixation With a Volar Approach Using a Cannulated Compression Screw for Acute Hook of Hamate Fractures.

PURPOSE: Optimal treatment of acute hook of hamate fractures (HHF) remains controversial. Isolated acute HHF can be treated nonsurgically or surgically (with excision of the hook or open reduction internal fixation). The authors present the functional outcomes of a case series of patients who were treated with minimally invasive volar fixation for acute HHF. METHODS: This retrospective study reviewed 6 patients with nondisplaced acute HHF treated with a minimally invasive volar approach and cannulated mini-screw fixation. The development of postoperative complications (tendon and ulnar nerve lesions), pain evaluated using a visual analog scale, and radiological union evaluated on computed tomography scan is reported. Wrist range of motion and grip strength were measured bilaterally. Mayo Wrist Score and Quick-Disabilities of the Arm, Shoulder, and Hand were assessed. All outcomes were measured at 1, 2, 3, and 6 months after surgery. RESULTS: Fixation of HHF through the volar approach was achieved in all cases with no complications. The clinical and radiological union rate was 100%. All patients were able to return to their work or hobbies after an average of 7 weeks. CONCLUSIONS: This study suggests that acute HHF can be treated successfully by open reduction internal fixation using a volar approach with minimal morbidity and complications, a good union rate, and a fast return to daily activities. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Evaluation of Articular Surface Similarity of Hemi-Hamate Grafts and Proximal Middle Phalanx Morphology: A 3D Geometric Morphometric Approach.

PURPOSE: Hemi-hamate arthroplasty has been described as a viable treatment option for unstable proximal interphalangeal joint fracture-dislocations. The procedure uses a dorsal distal hamate osteochondral graft to recreate the injured volar middle phalanx (MP) proximal base. The purpose of this study was to evaluate the similarity in shape of these articular surfaces using quantitative 3-dimensional methods. METHODS: Three-dimensional virtual renderings were created from laser scans of the articular surfaces of the dorsal distal hamate and the volar MP bases of the index, middle, ring, and little fingers from cadaveric hands of 25 individuals. Three-dimensional landmarks were obtained from the articular surfaces of each bone and subjected to established geometric morphometric analytical approaches to quantify shape. For each individual, bone shapes were evaluated for covariation using 2-block partial least-squares and principal component analyses. RESULTS: No statistically significant covariation was found between the dorsal distal hamate and volar MP bases of the middle, ring, or little digits. Whereas the volar MP bases demonstrated relative morphologic uniformity among the 4 digits both within and between individuals, the dorsal distal hamates exhibited notable variation in articular surface morphology. CONCLUSIONS: Despite the early to midterm clinical success of hemi-hamate arthroplasty, there is no statistically significant, uniform similarity in shape between the articular surfaces of the dorsal distal hamate and the volar MP base. In addition, there is wide variation in the articular morphology of the hamate among individuals. CLINICAL RELEVANCE: The lack of uniform similarity in shape between the dorsal distal hamate and the volar MP base may result in unpredictable outcomes in HHA. It is recommended that the variation in hamate morphology be considered while reconstructing the injured volar MP base in the procedure.

Dorsal buttress plate fixation for the treatment of fracture-dislocation of the fifth carpometacarpal joint with avulsion fracture of the hamate: a case report.

Fracture-dislocations of the fourth and fifth carpometacarpal (CMC) joints present a complex situation. Misdiagnosis and inadequate treatment may cause malunion and residual subluxation, which lead to painful arthritis and grip weakness. Open reduction along with internal fixation is the treatment of choice, but there is no consensus on an optimal treatment approach. We applied a novel surgical technique to treat a case of a fracture-dislocation of the fifth CMC joint with avulsion fracture of the hamate using a dorsal buttress plate between the hamate and the capitate. This method allowed for achieving rigid fixation without screw insertion across the bone fragments of the hamate. We could avoid the risk of unexpected fragmentation and unexpected damage to the volar neurovascular bundles around the hook of the hamate. Six months postoperatively, bone union was achieved and the reduction of the fourth and fifth CMC joints was maintained. Range of motion of the fourth and fifth CMC joints was almost equal to that on the contralateral side. 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.