Midcarpal Impaction Syndromes as a Rare Cause of Ulnar-Sided Wrist Pain: A Review.

Ulnar-sided wrist pain remains a commonly encountered diagnostic challenge, and its successful management requires a comprehensive understanding of the multiple conditions that can present with this symptom. Midcarpal impaction syndromes in the form of Hamato-lunate and Triquetro-hamate impingement have both previously been reported as rare potential causes of ulnar-sided wrist pain. Despite this, they remain poorly recognized and incompletely understood. This article reviews existing literature that describes the diagnosis and management of these clinical entities.

Symptomatic Congenital Coalition of the Pisiform and Hamate - A Case Report.

We describe a 13-year-old boy with piso-hamate coalition confirmed by X-ray. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed type 1 coalition according to the classification of DeVilliers Minnaar. Piso-hamate coalition is rare, and suspicions should be raised in instances of chronic ulnar-sided wrist pain, particularly in individuals with a history of elevated hand usage, especially amongst athletes engaging in intensive hand grip activities. Surgical resection of the synchondrosis site between the pisiform and the hamate is an efficacious intervention that can mitigate pain. Level of Evidence: Level V (Therapeutic).

The aetiology of fracture and nonunion in the hook of the hamate.

Fractures of the hook of the hamate are traditionally thought to be caused by direct trauma. A review of the anatomy and function of the hamate hook suggests that fracture is more likely as a result of a fatigue response that develops in the hook from repetitive load applied by the adjacent deep flexor tendons. Additional vascular compromise, from direct pressure of the tendons on critical local vessels, reduces blood flow leading to both mechanical and vascular effects that create pathological osseous change and weakening. These changes are likely to predispose to stress fracture and nonunion in repetitive gripping activities and are consistent with radiological findings.

Comparison of hamate versus second or third toe osteochondral graft using magnetic resonance imaging for reconstruction of proximal interphalangeal fracture-dislocations.

Hemi-hamate arthroplasty is a method used to reconstruct complex fracture-dislocations of the proximal interphalangeal joint of the fingers. Other graft sites, including the toe second and third phalanges, have been proposed as alternatives to hemi-hamate arthroplasty due to variable clinical outcomes and anatomy. Through a prospective magnetic resonance imaging (MRI)-based study in asymptomatic individuals, we aimed to characterize the anatomy of the proximal interphalangeal joint and compare this with the hamate, second and third toes to determine the closest anatomical match using pre-determined measurements. Our results show that the second and third toes have greater anatomical similarity to the proximal interphalangeal joint of the fingers compared to the hamate. High-resolution MRI is a reliable method of characterizing the anatomy of these structures and could be a useful clinical tool in determining reconstructive options in the management of this challenging injury.Level of evidence: II.

Excision of the hook of hamate in athletes using the carpal tunnel approach.

BACKGROUND: Hook of the hamate fractures can be managed conservatively or fixed using a screw, but excision is recommended for prompt return to activities. Although various approaches have been described, there is no gold standard. Herein, the authors have described their clinical experiences in excising the hook of the hamate using the carpal tunnel approach, in athletes. METHODS: A total of 36 athletes underwent excision of the hamate hook using the carpal tunnel approach. The mean age of the patients was 23 years, and most of them were baseball players (n = 31). RESULTS: The mean operation time was 33 min. None of the patients presented with any complications aside from transient pillar pain in five cases. All of them returned to their sports activities within an average of 27 days. CONCLUSIONS: In our study, excision of the hook of the hamate was performed safely via the carpal tunnel. The carpal tunnel approach reportedly provides superior benefits over other approaches.

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.

Hamate vs. capitate grafting for proximal interphalangeal joint fracture-dislocation: an MRI-based study of 35 hands.

We examined the MRI scans of 35 adult hands to assess the feasibility of the hamate and the capitate as potential donor grafts in the management of comminuted intra-articular fractures at the base of the middle phalanges. Essentially neither the hamate nor the capitate were perfect anatomic matches in most digits, but the capitate had the advantage of having more uniform facets, and the capitate facet shapes were similar to those of the little finger. The measurement of angles in the coronal and sagittal plane showed that in some respects the differences between the potential graft and the base of the middle phalanges were smaller for the capitate than for the hamate. Moreover, the sagittal morphology of the capitate made it less prone to joint overstuffing than the hamate. We conclude that the capitate may be considered as a graft donor in selected cases, especially for the little finger.

A Comparison of the Outcomes of Excision of the Fractured Hook of Hamate via a Carpal Tunnel Approach versus a Lateral Approach.

Background: The excision of the hook of the hamate is an accepted modality for the treatment of hook of hamate fractures. Three surgical approaches to the hook of hamate have been described in literature. This includes two palmar approaches namely the Guyon canal approach and the carpal tunnel approach, and the lateral approach. The aim of this article is to compare the outcomes of the carpal tunnel approach and the lateral approach. Methods: Twenty-four patients with hook of hamate fractures were treated by excision of the hook of hamate. The hook of hamate was approached via the carpal tunnel in 15 patients and via the lateral approach in 9 patients. The outcomes with regard to duration of the surgery, complications such as pain, sensory disturbance and scar problems and time to return to sports were measured and analysed. Results: There were no significant differences in outcomes between the carpal tunnel and the lateral approach for excision of hook of hamate fractures. Conclusions: The outcomes of excision of the hook of hamate via the carpal tunnel approach and the lateral approach are similar. The decision to choose an approach should be based on the surgeon's familiarity with the approach. Future studies should include a comparison with the Guyon canal approach preferably in a homogenous group of patients. Level of Evidence: Level IV (Therapeutic).

Arthroscopic Excision of Hamate Osteoid Osteoma.

Osteoid osteoma is considered the most common benign bone forming tumor accounting for 12% of all benign bone tumors. The carpus is a rare site for this tumor but quite a few cases were reported before. The lesion can be subperiosteal, cortical or medullary. Computed tomography scan is the gold standard diagnostic study, whereas magnetic resonance imaging can result in delaying the diagnosis as reported in the literature. Open excision with or without grafting was the technique of choice in most reviewed cases in the literature. In this paper we will illustrate a minimally invasive technique using wrist arthroscopy for an osteoid osteoma of hamate proximal pole. This minimally invasive arthroscopic technique provides a rapid recovery for patients with lesions that are accessible to wrist arthroscopy.

Hook of Hamate Fractures.

Hook of hamate fractures are uncommon injuries with unclear prevalence. Classic presenting symptoms include volar-ulnar hand/wrist pain and weakness in grip, with possible ulnar nerve paresthesias. Patient factors, such as activity level and desired return to work/sport, shape the most appropriate treatment regimen although excision of the hook has been adopted by most surgeons. Overall, once patients receive the correct diagnosis and are treated, good outcomes with high satisfaction rates are expected.

First reported case of a coronal hamate fracture associated with intrusion of the fifth metacarpal base, together with a fracture of the fourth metacarpal base.

We present a case reporting a rare combination of base of fourth metacarpal fracture and coronal body of hamate fracture, treated conservatively with excellent results. High index of suspicion for undetected bony injuries drove the execution of a CT scan, which allowed us to make a full correct diagnosis and plan treatment. Moreover, this case becomes the first reported case in the literature of such injury causing the intrusion of the base of the fifth metacarpal within the hamate bone, thus causing the coronal pattern of the hamate fracture. Differently from the common surgical management of this type of injury, we successfully treated this patient with close reduction and immobilisation, with full recovery after 3 months.

Unsuccessful Intervention of CT-Assisted Osteosynthesis for Stress Fractures of the Hook of the Hamate: A Report of 3 Cases.

CASE: We performed computed tomography (CT)-assisted dorsal approach osteosynthesis for stress fractures of the hook of the hamate using the dorsal approach in 3 high school baseball players in the hybrid operating room. Bony union was observed in all patients on CT. All patients were able to play baseball without pain for at least 6 months after surgery. However, refractures were observed in all patients at a mean 9.7 months after surgery. CONCLUSION: The indications of osteosynthesis for stress fractures of the hook of the hamate in baseball players should be carefully considered.

Triquetrum osteotomy to approach an otherwise inaccessible coronal malunion of the hamate.

Fractures of the hamate are rare, and a clear treatment algorithm does not exist. Nonetheless, surgical treatment is generally recommended for displaced fractures using a dorsal approach. There is also a lack of data on hamate malunion. We present a case of a 28-year-old female with a coronal malunion of the hamate and hamate hook fracture. Because the triquetrum prevented direct access to the fracture, we planned and undertook a transtriquetral coronal osteotomy based on three-dimensional computed tomography imaging data. After removing the bone callus, reduction was possible with subsequent fixation. We recommend performing a transtriquetral osteotomy to treat an otherwise inaccessible fracture or malunion of select hamate fractures.

The Effect of Hamatum Curvature Angle on Carpal Tunnel Volumetry: A Mathematical Simulation Model.

In carpal tunnel volume measurements, the angle of the hamatum curvature is not considered a variable, and its effect on carpal tunnel volume has not been investigated. We hypothesize that a change in the anatomical angle of the hamatum curvature changes the carpal tunnel volume. To prove our hypothesis, we used a mathematical simulation model considering the carpal tunnel as a truncated cone. We reviewed the wrist CT scans of 91 adults (>18 years of age), including 51 men and 40 women. We measured the angle of the hamatum curvature in the CT scans. We measured cross-sectional areas at the outlet of the carpal tunnel at the level of the trapezium and hook of hamate (r1) and at the inlet at the level of the scaphoid and pisiform (r2) and the length (h) of the carpal tunnel. We attempted to calculate the effect of 2 degree by 2-degree changes in the angle of the hamatum curvature between the angles of 98° and 140° on the carpal tunnel volume. The mean angle of the hook of hamatum of the subjects was 122.55° ± 8.20° (range, 97.20° - 139.31°). No suitable cutoff point was found for the angle values. There was no difference between the gender groups according to the angle value. The data clearly show that there is a high correlation between carpal tunnel volume and the angle of hamatum curvature. The results of our study emphasize the importance of taking into account the anatomical features of the hamatum bone, especially the angle of curvature, which may play a predisposing role in idiopathic carpal tunnel syndrome.

Coronal Hamate Fractures with Carpometacarpal Dislocation Treated Effectively Using Headless Compression Screws with Percutaneous Pinning Fixation by Using the 2-Directional Approach: A Report of 2 Cases.

CASE: Coronal shear fractures of the hamate are relatively rare injuries. Surgical intervention is recommended for displaced fractures. However, there is no established surgical procedure for the displaced coronal shear fractures of the hamate. Therefore, we present 2 cases of the displaced coronal hamate fracture with metacarpal dislocations, which were successfully managed with open reduction and internal fixation, using the headless compression screw by the 2-directional approach. CONCLUSION: Our procedure ensured that the screw's distal end captured the hamate hook, and the displaced bone fragments were reduced considerably in both cases.

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.

The Effect of Thumb Immobilization on Fractures of the Hook of the Hamate: A Cadaver Study.

Background: Fractures of the hook of the hamate are rare. Nonoperative management has historically been immobilization in a short arm cast (SAC) without thumb immobilization with a high reported incidence of nonunion. The high prevalence of nonunion following nonoperative treatment may be secondary to motion at the fracture site. The transverse carpal ligament's attachment to the hook of the hamate results in movement at the fracture site during thumb motion. Methods: A cadaveric study using 8 fresh frozen cadaver arms amputated at the mid-humeral level was performed. Computed tomography (CT) imaging was used to assess the bony anatomy and assure no preexisting fractures were present. Osteotomy of the hook of the hamate was performed through a skin incision proximal to the hook of the hamate and the transverse carpal ligament. Each arm was then mounted in a jig designed to hold and stabilize the arm and hand in supination. CT scans were performed without cast immobilization with the thumb in extension and abduction, with SAC without thumb carpometacarpal joint immobilization, and SAC with thumb carpometacarpal joint immobilization. Results: Motion of the fractured hook of the hamate was found to occur in all noncasted specimens, greatest with base fractures. SAC without thumb immobilization had little to no effect in eliminating fracture motion. SAC including the thumb reduced fracture motion in all specimens. Conclusions: Previous poor experience with nonoperative management of fractures of the hook of the hamate may be partially due to inability to adequately immobilize the fracture fragment. Fracture motion of the hamate hook occurs during thumb movement, likely from traction on the fracture fragment by the transverse carpal ligament.

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.

Value of cross-sectional area of median nerve by MRI in carpal tunnel syndrome.

BACKGROUND: Carpal tunnel syndrome is diagnosed based on history, physical examination, and nerve conduction testing; however, there are no clear criteria for the diagnosis of carpal tunnel syndrome. Recently, studies have aimed to diagnose carpal tunnel syndrome through ultrasound or MRI. The purpose of this study was to compare and analyze the cross-sectional area of the median nerve between patients with carpal tunnel syndrome and a control group. METHODS: From July 2015 to August 2017, we retrospectively analyzed fishery and white-collar workers (164 people, 37 men, 127 women). Carpal tunnel syndrome was diagnosed on the basis of both physical examination and nerve conduction testing. A negative result in either test led to exclusion from the study. RESULTS: In total, 164 wrist MRI were retrieved, with 67 patients diagnosed with carpal tunnel syndrome and 97 patients allocated to the control group. The mean value of cross-sectional area at the pisiform was 18.8 mm2 in the MRI of the carpal tunnel syndrome patients and 12.1 mm2 (p-value <0.05) in the control group. The mean value of cross-sectional area at the hook of hamate was 11.70 mm2 and that at the control group was 11.67 mm2 (p-value 0.055). CONCLUSION: Cross-sectional area at pisiform in MRI is a valuable factor in the diagnosis of carpal tunnel syndrome and in predicting the duration of pain.