Fracture of the hook of the hamate

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.

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.

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.

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.

Isolated hook of hamate fracture in sports that require a strong grip comprehensive literature review

BACKGROUND

The aim of the study was to report characteristics of isolated hook of hamate fractures related to sports that require a strong grip and to identify factors affecting early diagnosis and recovery period.

METHODS

A comprehensive literature search was conducted using MEDLINE, EMBASE, SCOPUS, Web of Science, the Cochrane Central Register of Controlled Trials, the World Health Organization International Clinical Trials Registry Platform, and the clinical trials registry and database of the US National Institutes of Health (ClinicalTrials.gov). There were no limits on the language or year of publication.This article included case reports and literature reviews for patients with isolated hook of hamate fractures related to sports that require a strong grip from 1977 to 2016.Two experienced reviewers extracted data from each study. The following data were extracted: sample size, patient's characteristics, cause of injury, injury side, time to diagnosis and symptoms, physical examination results, diagnostic work-up, treatment, complications, and recovery period.

RESULTS

A total of 21 case reports and literature reviews with 120 patients satisfied our inclusion criteria. There was no significant difference in the time to diagnosis between the group before computed tomography (CT) was widely used and the group after CT was widely used. Recovery period showed a positive relationship with age (coefficient = 0.418, P < .01), time from injury to diagnosis or surgery (coefficient = 0.206, P < .05), and type of athlete (coefficient = 0.270, P < .01). On multiple stepwise regression analysis, recovery period was significantly associated with age (β = 0.418, P = .00), but not with time from injury to diagnosis or surgery.

CONCLUSIONS

Advance in diagnostic techniques does not guarantee early diagnosis of hook of hamate fractures. Strong suspicion of the disease with physical examination and carefully hearing patient's history are important for early diagnosis and management for patients with hook of hamate fractures.

Closed Rupture of the Flexor Tendons of the Little Finger Secondary to Non-Union of Fractures of the Hook of the Hamate

We report six patients with closed flexor tendon rupture affecting the little finger, occurring secondarily to non-union of the hook of the hamate bone. The ununited fragments were separated from the basal part of the hook by more than 1 mm. The fragments were also rounded and showed marginal sclerosis. Non-union was located in the middle part of the hook in three patients, the tip in two, and the base in one. At operation, the fragments were removed in all patients. Five patients were treated by free tendon grafts using three palmaris and two plantaris grafts and one underwent tendon transfer. Postoperative total range of active motion of the little finger averaged 218° (range 185–265°). All patients returned to their original employment. This series would suggest that flexor tendon rupture can occur after fracture of the hook of the hamate bone, even when the ununited fragment is small and/or rounded.

Tendon rupture of the flexor digitorum profundus of the little finger secondary to hamate non-union

Several cases of hamate fracture and non-union have been reported. The hook of the hamate acts as a pulley for the flexor tendons for the little and ring fingers. Hamate non-union is frequently associated with irritation of the adjacent soft tissues. We report the case of hamate non-union that was only detected because of a flexor digitorum profundus tendon rupture in the little finger, associated with tendinopathy of both flexor tendons of the ring finger.

HIGH INCIDENCE OF HAMATE HOOK FRACTURES IN UNDERWATER RUGBY PLAYERS: DIAGNOSTIC AND THERAPEUTIC IMPLICATIONS

Hamate hook fractures are rare injuries but appear to occur frequently in underwater rugby, the reason for which was investigated in this study.

High-level underwater rugby players with hook fractures diagnosed during a five-year interval (2005–2010) were studied retrospectively. Medical data on these patients were reviewed for information on the mechanism of injury, type of fracture, radiological imaging, treatment, and outcome.

In ten patients, hook fractures of the leading hand were confirmed by computed tomography, all of which were associated with specific injuries during underwater rugby games. Conservative treatment resulted in delayed healing or non-union, wherefore fragment excision and open reduction and internal fixation was performed in ten and five patients, respectively, while two patients declined surgery. After surgery, all patients were able to play underwater rugby again.

In underwater rugby, hook fractures occur frequently due to high and repeated forces applied to the leading hand during games.

Combined intraarticular fracture of the body and the hook of hamate: an unusual injury pattern

Isolated fractures of the carpal hamate are rare. We describe a case of 28-year-old male patient who sustained a rare pattern of wrist injury: combined intraarticular fracture of the body and the hook of hamate in the non-dominant left hand. The patient was treated with percutaneous pinning of the fracture of hamate body.

Two-staged tendon reconstruction in flexor tendon ruptures secondary to fracture of the hamate hook

We report a case of 2-staged reconstruction of flexor tendons ruptured spontaneously by attrition. A 49-year-old man presented with inability to flex the ring and little fingers of his left hand. Preoperative computed tomographic scans revealed fracture of the hamate hook. At the time of the operation, both the flexor superficialis and profundus of the little finger and the flexor profundus tendon of the ring finger were ruptured adjacent to the fracture site of the hamate. Because the flexor tendon rupture secondary to the fracture of the hamate is extremely rare, and surgical outcomes of previous reports are not satisfactory, a decision was made to perform 2-staged reconstruction of ruptured flexor tendons. The surgical result was excellent with complete restoration of full range of motion. This report describes for the first time to our knowledge, the technique, and rehabilitation of 2-staged tendon reconstruction in a patient with hook of hamate fracture.

Optimierung von konventionellen Röntgenaufnahmen zur Erkennung von Hamulus ossis hamati Frakturen

Fractures of the hook of the hamate are a rare event. The fracture cannot always be detected clinically and standard radiographs do not always provide an overlap-free image of the hook of the hamate, so that fractures can easily be overlooked. The objective of the present study was to examine if the sensitivity of detecting hamulus ossis hamati fractures can further be improved by a modified conventional radiographic projection. After dissection of the hook of the hamate on 10 cadaver hands, a fracture was produced close to the base using a surgical chisel. Conventional radiographs were then performed in four different projections (dorso-palmar, lateral, carpal-tunnel and oblique view). The oblique view was obtained in a 45 degrees supination position, slight extension and radial duction, with the tube tilted from distal to proximal by 30 degrees. An axial spiral CT was used as a reference for detection of the fracture. The highest sensitivity of the conventional radiographs, with 8/10 identified fractures (80%), was achieved by the oblique view. The carpal-tunnel view with 4/10 (40%) and the dorso-palmar projection with 3/10 (30%) were much lower. All fractures were missed in the lateral projection. If all of the conventional radiographic projections are taken into account, the sensitivity is increased to 90%. All of the fractures were reliably detected in the axial CT-image. If a hamulus ossis hamati fracture is suspected clinically, in addition to the dorso-palmar and carpal-tunnel view, the special oblique view described here should be performed as a third projection plane, while the lateral view can be dispensed with. However, even if all projections are taken into account, a negative finding in the conventional radiographic imaging does not exclude a fracture with absolute certainty. In such cases, a CT or MRI should be performed to exclude a fracture.

Therapeutic Alternatives in Nonunion of Hamate Hook Fractures

Symptomatic nonunion frequently results after conservative treatment of hamate hook fractures, emphasizing the need of appropriate surgical strategies. A retrospective analysis of 8 patients with nonunions treated by fragment excision or open reduction and internal fixation (ORIF) at 3 centers was performed. The literature was reviewed for treatment options, as bone grafting and low-intensity pulsed ultrasound. Although fragment excision is advocated as the "gold standard" in nonunion, reports on functional results are controversial, and recent anatomic and biomechanical studies of the hook challenge this opinion. In our patients, complete relief of symptoms and comparable functional results were observed after ORIF or fragment excision. Bone grafting could supplement ORIF in selected cases. Low-intensity pulsed ultrasound may evolve as a conservative treatment option. Several alternatives to hook excision are available aiming at complete anatomic and functional recovery of hamate hook nonunion. Further experience is needed before general recommendations can be formulated.

Hook of Hamate Fractures: Critical Evaluation of Different Therapeutic Procedures

The treatment of choice in nondisplaced hook of hamate fractures is conservative, with lower arm splinting. Displaced fractures should be treated operatively, whereby excision of the fragment or open reduction and internal fixation are described. A hamulus ossis hamati fracture was verified in 14 patients (mean age, 42 years; range, 21 to 73 years) including 11 men and three women. In six patients (42.9 percent), conservative treatment was initiated immediately after trauma with a lower arm cast for 6 weeks, and eight patients (57.1 percent) were operated on primarily. In five patients (35.7 percent), the fragment was excised, and in three patients (21.4 percent), an open reduction and internal fixation was performed using a screw. In five of six patients treated conservatively, nonunion of the fracture with persisting clinical symptoms developed. All of those patients were treated operatively, whereby three patients underwent excision and two patients underwent screw fixation, which led to elimination of the symptoms. One patient was asymptomatic despite nonunion of the fracture and rejected surgery. All of the eight patients operated on primarily were asymptomatic 3 months after surgery. Therefore, the success rate of primary surgical treatment (eight of eight) was significantly higher compared with conservative treatment(one of six). Finally, all 14 patients were asymptomatic at late postoperative follow-up. The clinical outcome of patients with hook of hamate fractures treated conservatively was disappointing. Therefore, primary surgical treatment is recommended. In our patients, excision and open reduction and internal fixation led to comparable results.

Diagnostic imaging for fracture of the hook of the hamate

We experienced 16 patients with a fracture of the hook of the hamate. The routine posteroanterior view raised the suspicion of fracture in four of 13 patients (31%), the carpal tunnel view showed the actual fractures in six of 14 patients (43%), and the supine oblique radiographic view of the wrist showed fractures in eight of ten patients (80%). Computed tomography corroborated the fracture in all eight patients (100%). Computerized tomography proved most useful for accurate diagnosis of fracture of the hook of the hamate.

Imaging of hamate bone fractures in conventional X-rays and high-resolution computed tomography. An in vitro study

RATIONALE AND OBJECTIVES

To examine the ability to image fractures of the body and hook of the hamate bone in conventional X-rays and high-resolution computed tomography (HR-CT).

MATERIALS AND METHODS

In an in vitro experiment using 18 cadaver hands, the hamate bone was fractured at different places. Before and after fracture, conventional X-rays were taken in different planes (anteroposterior, lateral, oblique, and carpal tunnel), and HR-CT was performed with 2-mm layer thickness in the axial, sagittal, and coronal plane.

RESULTS

Taking into account all the conventional X-ray projections applied, the in vivo experiment revealed a sensitivity of 72.2%, a specificity of 88.8%, and an accuracy of 80.5%. For the HR-CT, the sensitivity was 100%, the specificity was 94.4%, and the accuracy was 97.2%.

CONCLUSIONS

Fractures of the body and hook of the hamate cannot always be detected with certainty in the conventional X-ray image, even if different projectional planes are used. The HR-CT is the imaging procedure of choice for further clarification, and an axial or sagittal plane should be selected.

Hypothenar hammer syndrome caused by recreational sports activities and muscle anomaly in the wrist

A 34-year-old man with digital ischemia is reported. Angiography revealed thromboembolic occlusions of the proper digital arteries of the index, middle, and ring fingers and a tortuous ulnar artery in Guyon's canal. Though hypothenar hammer syndrome was suspected, there was no relevant occupational history. Magnetic resonance imaging and magnetic resonance angiography demonstrated an anomalous muscular sling around the ulnar artery immediately adjacent to the hook of the hamate. The ulnar artery showed mural thrombi in its tortuous segment. These findings were confirmed during operative exploration. After thrombectomy and embolectomy the involved segment of the ulnar artery was replaced by an autologous vein graft. Postoperatively there was complete resolution of the symptoms. Only during convalescence did it become clear that the patient was a passionate golfer.

Nonoperative treatment of acute hamate hook fractures

Six patients with acute and two patients with subacute nondisplaced fractures of the hamate hook were treated with immobilization. The patients with acute fractures were treated within 7 days of the injury, and those with subacute fractures were treated after 7 days. Seven of the eight patients showed documented healing of their fractures. At follow-up (average 8 months) all seven were free of symptoms. One patient with a subacute fracture did not comply with treatment and had a painful nonunion. Our results show that hamate hook fractures that are diagnosed early may heal with nonoperative management. Fractures that fail to heal with immobilization or those with chronic nonunion should be treated with excision of the hook fragment.

Radiographic and orthopedic evaluation of wrist trauma

This paper was written to enable radiologists to contribute more usefully to the diagnosis and treatment of various wrist injuries. All imaging modalities are discussed to equip the radiologist for his difficult task. We present a systematic approach to the evaluation of wrist trauma patients beginning with initial plain films and proceeding through more invasive or sophisticated studies in order to achieve a definitive diagnosis. Toward this end a flow chart has been developed as a quick reference source. The authors have then described the anatomy and kinematics of the wrist to further the radiologist's understanding of the forces involved and the injuries produced by trauma. From this foundation individual injuries are then discussed together with the best methods of making the proper diagnosis of each. Criteria for adequate treatment of various injuries are also presented.

An unusual combination of simultaneous fracture of the tuberosity of the trapezium and the hook of the hamate

A case of simultaneous fracture of the tuberosity of the trapezium associated with fracture of the hook of the hamate is described. The mechanism of injury is thought to be traction force through the transverse carpal ligament caused by flattening of the transverse carpal arch.

Excision of the hook of the hamate: a retrospective survey and review of the literature

Fractures of the hook of the hamate frequently fail to unite. In symptomatic nonunion, surgical excision of the hook has provided relief of pain in the few reported cases. In a survey of surgeons, 133 cases of excision of the hook to treat nonunion were reviewed retrospectively. The complication rate associated with excision is three percent. These complications, such as injury to the ulnar nerve or the superficial palmar arch and median nerve paresthesias secondary to retraction are due more to the surgical exposure than the actual excision.

Fracture of the hamate hook

Twenty-one cases of hamulus fracture are presented. Diagnosis depends on clinical acuity. The most common symptom is pain in the palm that is aggravated by grasp. Weakness of grasp and dorsal wrist pain are also common. Ulnar nerve paresthesia or weakness and mild carpal tunnel syndrome are frequently present. Tenderness directly over the hamulus is always present, and grip strength typically is diminished. Tenosynovitis, tendon fraying, or tendon rupture may be demonstrated in 25% of the cases and is not related to the use of steroids. Lateral trispiral tomography is clearly superior to the other diagnostic methods. Excision produced generally excellent results, particularly in patients with an athletic injury or with no associated additional injury. A nonathletic injury or the presence of associated trauma adversely affected results. Immediate immobilization of acute fractures may result in fracture healing and obviate operative intervention. Open reduction and internal fixation is feasible but offers little advantage over excision.

The carpal tunnel view: helpful adjuvant for unrecognized fractures of the carpus

We present four cases of carpal bone fractures which were not recognized on standard anteroposterior (AP) and lateral views of the wrist. When there is clinical suspicion of fractures of the hook of the hamate, pisiform, or trapezium, either because of the mechanism of injury or clinical presentation, a carpal tunnel view of the wrist is often helpful to disclose previously unrecognized fractures.

Hook of the hamate fractures in athletes

Five patients have been treated for six hook of the hamate fractures over the past 8 years by the authors. Of these, four patients were professional baseball players and one patient was an accountant. All fractures occurred while playing baseball; four while swinging a bat, and two secondary to a fall on an outstretched hand. Roentgenographic diagnosis was made by carpal tunnel view alone in two, oblique and carpal tunnel view in one, bone scan and subsequent carpal tunnel view in two, and computerized tomography in one fracture. Five of the fractures were through the base of the hook, while one was toward the tip. All patients ultimately underwent hook resection, four early and two late. The patient who sustained the tip of the hook fracture underwent resection of the fracture only to refracture the same hook at its base 6 months later. All patients returned to their previous level of activity in 6 to 8 weeks after surgery without loss of function. Hence, it is the authors' opinion that the entire hook should be resected to the base of the hamate as the primary form of treatment in hook of the hamate fractures.

Bipartite hamulus with ulnar tunnel syndrome--case report and literature review

Increasing reports of fractured hamate hooks have provided a sharper focus on causes, diagnosis, treatment, and associated anomalies such as ulnar neuropathy, bipartition, and accessory ossicles. This case report, presenting ulnar tunnel syndrome with bilateral hamulus bipartition, illustrates the relation between these anomalies.