Conservative Treatment for Hook of Hamate Fracture: A Case Series of 18 Patients

doi:10.21203/rs.3.rs-5296304/v1

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Conservative Treatment for Hook of Hamate Fracture: A Case Series of 18 Patients

https://doi.org/10.21203/rs.3.rs-5296304/v1

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Background

The cause of hook of hamate fractures is either a fatigue fracture type because of repetitive stress on the hook of hamate from athletes involved in gripping sports (e.g., golf, tennis, and baseball) or a traumatic occurrence because of falls or other injuries. The recommended treatment involves the excision of bone fragments to facilitate athletes’ early return to sports; excision surgery is also performed in cases of trauma. However, some patients prefer nonsurgical treatment options, and conservative treatment should be considered. This study aimed to present a case series of 18 patients who were conservatively treated for hook of hamate fractures.

Methods

This study included 18 (13 males and 5 females, with 6 cases on the right side and 12 on the left) patients who desired conservative treatment and could be followed up until bone union was achieved. The average age of the patients was 49.7 (range, 24–72) years. The average time from injury to consultation was 4.7 (range, 0.2–21.4 weeks). The treatment involved 4 weeks of casting from the forearm to the metacarpophalangeal joint, followed by 8 weeks of splint fixation of the wrist. Follow-up computed tomography scans were performed every 4 weeks.

Results

Bone union was achieved in all patients. The average duration of casting was 3.3 (range, 0–5) weeks, and the average duration of splint fixation thereafter was 9.3 (range, 0–28) weeks. No complications were associated with cast immobilization.

Conclusion

Conservative treatment with external fixation may be an option for hook of hamate fractures.

Conservative Treatment

Hook of Hamate

Fracture

A common cause of ulnar-sided wrist pain is a hook of hamate fracture, a relatively rare condition that accounts for approximately 2% of all carpal bone fractures [1]. Its mechanism of injury often involves direct trauma (such as falling onto an outstretched hand) or repetitive stress, making this fracture more common in active individuals than in sedentary individuals. The hook of hamate plays a critical role in hand function, serving as an attachment site for important structures, such as the transverse carpal ligament and flexor tendons. Because of their location, fractures of the hook can result in significant pain and functional impairment. However, diagnosing these fractures is challenging because they are often missed on standard radiographs, particularly when specialized views, such as oblique or carpal tunnel X-rays, are not used. This frequently leads to a delayed diagnosis and increases the risk of nonunion and persistent pain [2].

Generally, surgical excision is the preferred treatment for these fractures, especially in athletes seeking a quick return to activity. Surgery can relieve symptoms by removing the fractured fragment; however, it is associated with postoperative complications, such as reduced grip strength and ulnar nerve irritation. Although surgery is often successful in resolving symptoms, it is not without risks, and not all patients, especially those who are not professional athletes, require or desire surgical intervention.

In this report, we present a case series of 18 patients who were conservatively treated for hook of hamate fractures. We aimed to demonstrate that conservative management is a viable and effective option for these fractures, particularly in patients who prefer nonsurgical treatment. We discussed the clinical outcomes, including factors contributing to successful bone healing, and the conditions under which conservative treatment may be the most appropriate. The aim of this study is to clarify the clinical course of conservative treatment in the management of hook of hamate fractures and to propose a conservative approach as an alternative to surgery for specific patients.

The study was conducted in accordance with the principles outlined in the Declaration of Helsinki. This retrospective case-control study, classified as Level III evidence, involved a review of a database to identify clinical cases of patients with hook of hamate fractures who underwent conservative treatment. This study included 18 patients diagnosed with a hook of hamate fracture between January 2016 and June 2024, with a period of 8 years and 6 months. These patients opted for conservative treatment and were followed up until bone union was confirmed. We investigated the patient's symptoms, medical history, clinical symptoms, imaging findings, treatment options, complications, and treatment course. The cohort included 13 males and 5 females, with 6 on the right side and 12 on the left side. The average age of the patients was 49.7 (range, 24–72) years.

For immobilization, we applied a cast extending from the proximal one-third of the forearm to the metacarpophalangeal (MP) joint. Subsequently, additional immobilization was performed using a cock-up splint. To confirm the bone union, computed tomography (CT) scans were performed every 4 weeks.

Regarding the informed consent process, the data used in this retrospective study were reviewed under an "opt-out" consent policy, in accordance with our institutional ethics guidelines. This policy allowed for the use of patient data collected during routine clinical care without the need to re-contact participants for additional consent, thereby avoiding the burdensome process of re-consent for each participant included in the study.

The case presentations are presented in Table 1. The causes of injury were a fall on an outstretched hand in 16 patients and a golf swing in 2 patients. According to the fracture classification [3], there was 1 case of type I (fracture at the tip), 2 cases of type II (fracture at the central portion), and 15 cases of type III (fracture at the base). The average time from injury to consultation was 4.7 (range, 0.2–21.4) weeks. The average duration of cast immobilization was 3.3 (range, 0–5) weeks, followed by an average of 9.3 (range, 0–28) weeks of splint immobilization. All patients achieved bone union and returned to their pre-injury level of activity. One case of recurrence occurred after a golf swing that required re-immobilization. No associated injuries, such as flexor tendon rupture or nerve damage, were observed. The following are case presentations:

Case 7 (Fig. 1)

A 43-year-old man sustained a left hand injury when he extended his arm forward during a fall. He initially sought treatment at a local clinic but remained undiagnosed, with pain persisting for 4 months before he sought further evaluation. He reported pain during golf swings and when putting weight on his hand. Upon clinical examination, tenderness was noted at the hook of hamate on the proximal ulnar side of the palm, and a type III hook of hamate fracture was confirmed on CT. The patient was treated with 4 weeks of cast immobilization and 8 weeks of splint immobilization, with instructions to avoid overexertion of the ring and little fingers. Two months after his initial clinic visit, the fracture healed, and remodeling was observed by the third month. Six months later, the patient was pain-free and had normal daily life.

Case 12 (Fig. 2)

A 72-year-old woman sustained an injury from a fall while running and was treated with 6 weeks of cast immobilization at another hospital. However, owing to the development of nonunion, the patient was referred to our clinic. CT revealed separation at the fracture site. Considering that 7 weeks had passed since the injury, conservative treatment was selected. The patient underwent 4 weeks of cast immobilization, during which early bone bridging was observed, indicating callus formation. Splint immobilization was continued while the patient was under observation. During the splint period, no restrictions were placed on the patient’s participation in running or marathons. Full bone union was achieved 7 months after the injury.

Case 18 (Fig. 3)

A 50-year-old man who played golf once a week and practiced twice a week experienced pain during a golf swing. Owing to persistent pain, he visited our clinic 3 months after the injury. Tenderness was noted at the hook of hamate, and the patient was treated with cast immobilization for 4 weeks, followed by splint immobilization. His symptoms resolved, and he was able to return to golf. Two years later, the patient returned with the same symptoms, and refracture at the same site was confirmed. As the patient did not wish to undergo surgery, conservative treatment was administered. Bone union was achieved, and since then, he has been enjoying golf pain-free after changing the way he grips the club.

The hook of hamate protrudes prominently into the palmar region, forming Guyon’s canal on its ulnar side, together with the pisiform and pisohamate ligaments, through which the motor and sensory branches of the ulnar nerve pass. On the radial side, the transverse carpal ligament is attached to the tip of the hook of hamate, forming a part of the carpal tunnel. Muscles and ligaments that directly attach to the hook of hamate include the flexor digiti minimi brevis, opponens digiti minimi, and pisohamate ligament. Although the flexor digitorum profundus tendon does not directly attach to the hook of hamate, it wraps around the radial side of the hook during wrist ulnar deviation and little finger flexion, allowing the hook of hamate to function like a pulley [4, 5].

Hook of hamate fractures have several characteristics. First, they are rare, accounting for only approximately 2% of all carpal bone fractures [1]. Their injury mechanisms often include stress fractures caused by repetitive forces during sports, such as golf, baseball, and racket sports [6]. These fractures can also occur because of direct trauma, such as falling onto an outstretched hand [7]. One characteristic of hook of hamate fractures is the difficulty in achieving bone union. Blood supply to the hook of hamate is provided by one vessel from the radial side, nourishing the radial side of the base, and two smaller vessels from the medial side, nourishing the medial base and tip [8, 9]. Although vascular issues have been considered, there are no reports of avascular necrosis, suggesting that muscle and ligament forces are more likely to affect healing than vascular factors [7]. Second, hook of hamate fractures are classified into three types based on their anatomical locations: type I, distal tip; type II, middle part; and type III, base of the hook. Type III fractures account for 75% of all hook of hamate fractures, and it is more difficult to achieve bone union in type II fractures [3]. However, in our study, bone union was achieved across all fracture types. Finally, diagnosing hook of hamate fractures can be difficult. Oblique and carpal tunnel radiographs are necessary, but fracture lines are often obscured by overlapping carpal bones [10]. CT or magnetic resonance imaging is useful for definitive diagnosis [2, 10], In this study, we used CT for both the diagnosis and follow-up of bone healing.

Surgical excision of the fracture fragment is frequently performed (8), and open reduction and internal fixation (ORIF) is also an option [11, 12]. However, postoperative complications have been reported in 25–59% of cases, with some residual symptoms. Sheridan et al. performed excision surgery on 145 professional baseball players, reporting postoperative ulnar nerve numbness in 2 patients, pain at the surgical site in 6 patients, and heterotopic ossification in 1 patient [6]. Additionally, a decrease in grip strength of 11–15% following excision of the hook of hamate has been noted [4, 13, 14]. Although not without risk, excision remains the first-line treatment for athletes seeking a quick return to sports [3]. In terms of bone union, the average duration of ORIF is 12.3 weeks [15], similar to the 12.6 weeks of immobilization in our cases of combined cast and splinting.

Among our cases, two golfers were treated conservatively, and both achieved bone union. Despite the high risk of nonunion associated with conservative treatment, causes of nonunion include poor blood supply to the hook of hamate [8], repetitive stress on the small fracture area [8], and delayed diagnosis [2]. The reported rates of nonunion are 6/25 (24%) (16), 5/6 (83%) [15, 16], and 3/3 (100%) [8], with many of these cases requiring excision after 6 weeks of immobilization failed to achieve bone union. Early diagnosis and timely surgical intervention are often recommended [17], which is understandable. In our study, 4 of 18 (22%) patients presented > 6 weeks after injury, and although the healing process was slower, all patients eventually achieved full bone union. Whalen et al. reported that all six cases of acute fractures treated conservatively healed after an average immobilization period of 11 weeks, and one of two delayed cases achieved bone union after 28 weeks [17].

Two key factors likely contributed to successful outcomes. First, it is important to maintain the patients’ motivation for continued treatment. This can be achieved by showing the progression of CT scans from successfully healed cases, helping them understand the healing process. Additionally, allowing them to observe their own CT progress enables them to experience the effectiveness of the treatment first. Second, during the initial 4 weeks of cast immobilization (up to the MP joints), the patients were allowed to move their fingers freely but were advised to avoid lifting heavy objects with their ring and little fingers.

One limitation of this study is that four sports-related cases underwent excision surgery during the same period. As observed in case 3, fractures caused by repetitive stress are prone to recurrence and may not be suitable for conservative treatment. Another limitation is that this is not a comparative study. Patient satisfaction may need to be evaluated in a future study with a comparative design.

In 18 patients with hook of hamate fractures, conservative treatment resulted in bone union without complications. Conservative treatment can be considered an option for hook of hamate fractures. Sharing the progress of fracture healing with patients is essential for ensuring the continuation of treatment.

Computed tomography

Metacarpophalangeal

ORIF

Open reduction and internal fixation

Ethics approval and consent to participate

This study was conducted in accordance with the principles of the Declaration of Helsinki and with the approval of the ethics committee of our institute.

Consent for publication

Written consent for publication was obtained from all study participants.

Availability of data and materials

The datasets used and/or analyzed in the present study are available from the corresponding author upon reasonable request.

Competing interests

No benefits in any form were received or will be received from any commercial party directly or indirectly related to the subject of this study.

Funding

Not applicable.

Author Contributions:

TT: Conception and analyzed the data, interpreted the data, and wrote the manuscript.

RF: Acquired and analyzed the data and revised the manuscript.

YY: Analyzed the data, interpreted the data, and revised the manuscript.

All authors were fully involved in the study and have approved the final version of the manuscript.

Acknowledgments

Not applicable

‘Clinical trial number:

Not applicable.

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Table 1 is available in the Supplementary Files section.

No competing interests reported.

Table1.xlsx
Table 1 List of all cases. Background and treatment duration

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Conservative Treatment for Hook of Hamate Fracture: A Case Series of 18 Patients

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Abstract

Background

Methods

Results

Conclusion

Figures

Background

Methods

Results

Discussion

Conclusions

Abbreviations

Declarations

References

Table 1

Additional Declarations

Supplementary Files

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