Available online at
ScienceDirect www.sciencedirect.com Chirurgie de la main 34 (2015) 44–48
Clinical case
Tendon rupture of the flexor digitorum profundus of the little finger secondary to hamate non-union Pseudarthrose de l’hamulus de l’hamatum responsable d’une rupture de tendon fléchisseur profond du cinquième rayon J. Gaillard a,*, S. Roy-Maillot a, E.-H. Masmejean b a
Service de chirurgie orthopédique et traumatologique & SOS main, hôpital Saint-Antoine, 184, rue du Faubourg-Saint-Antoine, 75571 Paris cedex 12, France b Service de chirurgie orthopédique et traumatologique & SOS main, hôpital européen Georges-Pompidou, 20, rue Leblanc, 75908 Paris cedex 15, France Received 31 May 2014; received in revised form 1 October 2014; accepted 5 October 2014 Available online 8 December 2014
Abstract 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. # 2014 Elsevier Masson SAS. All rights reserved. Keywords: Carpus; Non-union; Hamate; Flexor tendon; Rupture
Résumé Plusieurs cas de fractures et pseudarthroses de l’hamatum ont été rapportés. Son hamulus agit comme une poulie de réflexion pour les tendons fléchisseurs des cinquième et quatrième rayons. Les pseudarthroses de l’hamulus de l’hamatum sont souvent associées à un syndrome irritatif des structures adjacentes. Nous rapportons le cas d’un patient présentant une pseudarthrose de la base de l’hamulus de l’hamatum, diagnostiquée à distance devant une rupture du tendon fléchisseur profond du cinquième doigt, associée à une tendinopathie des deux tendons fléchisseurs du quatrième doigt. # 2014 Elsevier Masson SAS. Tous droits réservés. Mots clés : Carpe ; Pseudarthrose ; Hamatum ; Tendon fléchisseur ; Rupture
1. Introduction Carpal bones fractures are common and mainly affect the scaphoid; the other carpal bones are not fractured as often. Hamate fractures only make up 2% of carpal fractures [1,2]. Fractures of the hook-like process of the hamate (hamulus) are
* Corresponding author. E-mail address: [email protected] (J. Gaillard). http://dx.doi.org/10.1016/j.main.2014.10.147 1297-3203/# 2014 Elsevier Masson SAS. All rights reserved.
rare. Tessier et al. identified 42 published cases in 1983 [3]. The most common complications were injuries to the neighboring flexor tendons (ring and little finger). Cases of irritation of adjacent nerve pedicles (ulnar and median) have been described on rare occasions, leading to entrapment neuropathy in certain cases. This article reports the case of a patient who was diagnosed with hook of the hamate non-union only after finding a ruptured flexor digitorum profundus (FDP) tendon in the little finger and signs of flexor tendinopathy in the ring finger. The diagnosis was made 4 years after the initial injury event.
J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
45
2. Case report This was a 57-year-old, right-handed male patient who did not smoke and had no significant medical history. The clinical history went back to 2009, at which point the patient suffered an injury to his left hand while working with a tool. The patient had been treated with courses of non-steroidal anti-inflammatory drugs. Due to persistent pain, he consulted with a rheumatologist who twice injected corticosteroids into the metacarpophalangeal joint of the little finger; this provided transient pain relief but did not help him regain his strength. In March 2013, ultrasonography revealed tenosynovitis of the flexor tendons in the little finger. A/P and lateral radiographs were normal (Fig. 1A, B). An electromyogram (EMG) confirmed there was no peripheral nerve injury. He had been on sick leave for 3 months when he was referred to us. Clinically, the patient had carpal pain during passive finger curling, which was reproduced by specifically palpating the volar side of the hamate. The passive range of motion of the finger joints was complete and painless. There was reduced active flexion of the distal interphalangeal (DIP) joint of the little finger, which the patient indicated was present before the corticosteroid injections (Fig. 2A), and loss of tenodesis grasp with absence of flexion in the fifth DIP joint (Fig. 2B) during wrist extension. His average muscle strength measured on a Jamar dynamometer was 38 kg for the right hand and 18 kg for the left. A second ultrasonography exam revealed a rupture of the FDP tendon in the little finger with the proximal stump retracted to the distal volar wrist crease and the distal stump located at the shaft of the fifth metacarpal. CT scan revealed a non-union at the base of the hook of the hamate, with small subchondral cysts on both sides, but without osteophytes or condensation. The flexor tendons of the little finger and the FDP of the ring finger pass along the lateral side of this non-union (Fig. 3A). Magnetic resonance imaging (MRI) revealed additional injuries: tendinopathy of the flexor digitorum superficialis (FDS) of the little finger, tendinopathy of the FDP and FDS of the ring finger and subchondral cysts in the medial part of the head of the capitate (Fig. 3B–D). Surgical treatment was performed on an outpatient basis with regional anesthesia and a tourniquet. The approach consisted of a Brunner zigzag incision over the non-union site
Fig. 1. A/P (A) and lateral (B) radiographs of the wrist.
(Fig. 4A). The hypothenar eminence and carpal tunnel were opened to assess the extent of the damage (Fig. 4B). Non-union at the base of the hook of the hamate was confirmed (Fig. 4C). The FDP tendon in the little finger had ruptured, while the FDP tendon in the ring finger was inflamed but still intact. There were visible signs of inflammatory tendinopathy. The hook of the hamate was excised and the non-union site was leveled to prevent the tendon from being damaged when it rubs against the remainder of the hook’s base (Fig. 4D). The distal stump of the torn FDP was retrieved at the base of the fifth metacarpal and the proximal stump was retracted to the wrist and left in place (Fig. 4E). Because of the excessively large tendon defect, tenodesis of the distal stump of the torn FDP tendon to the FDS tendon was carried out by direct suture with a physiologically tensioned Pulvertaft weave (Fig. 5A, B). The repaired tendon was protected with a Duran brace for six weeks, which allowed for immediate protected mobilization. 3. Discussion The hamate has a hook-like process called the hamulus. This process is thin and elongated. The hook of the hamate can be palpated 1.5 to 2 cm distal to the pisiform on an angled line drawn from the pisiform bone and the head of the second metacarpal [4]. It can be compared to the mast of a ship, to which the transverse carpal ligament and pisohamate ligament
Fig. 2. Active flexion deficit of the DIP in the little finger (A) and loss of tenodesis grasp of the DIP in the same finger (B).
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J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
Fig. 3. CT scan reveals non-union at the base of the hook of the hamate, with small subchondral cysts on both sides (A). T1-weighted axial MRI slice showing tendinopathy of the FDP tendon of the ring finger and empty sheaths of the little finger over the fracture site (B). T1-weighted axial MRI slice showing tendinopathy of the FDP tendon of the ring finger and the proximal stump of the ruptured FDP in the little finger (C). T2-weight axial MRI slice of the metacarpal shafts showing the distal stump of the ruptured FDP tendon in the little finger and FDP tendinopathy in the ring finger (D).
are attached; this extends the distal tendon of the flexor carpi ulnaris, which has a hammock shape, and makes up the floor of Guyon’s canal [5,6]. The radial aspect of the hook acts as the medial margin of the carpal tunnel. The two-flexor tendons of the little finger bend around its concave surface. Its ulnar aspect forms the lateral edge of Guyon’s canal [6]. During finger flexion with the wrist in ulnar deviation, the FDP tendon of the little finger bends around a trochlea formed by the radial edge of the hook of the hamate [4]. The hook of the hamate can fracture in three locations: base, body and tip. In the patient described here, the fracture was located at the base. This is the most common type of fracture described in published studies. Stark et al. found that 47 out of 62 patients had a base fracture [5]. Of the 27 cases of flexor tendon rupture due to non-union of the hook of the hamate, the exact fracture site was only reported in eight studies [7–14]. Contrary to the findings of Pajares-López et al. [10], the hook of the hamate is fractured most often at its base [5]. The location of the non-union does not seem to be related the flexor tendon rupture [7]. The most common fracture mechanism is a direct impact to the hook itself [2–5,8]. This can occur after a patient falls and lands on the hypothenar side of the carpus or more typically, in those who participate in sports such as golf, squash, tennis or baseball. These sports all require use of a club, racket or bat where the distal stump of the handle presses against the ulnar side of the hook of the hamate. The handle is held in the dominant hand by a tennis player, but in the non-dominant hand by golfers and batters [5]. More rarely, the fracture occurs indirectly by traction on the flexor retinaculum, which stretches to either side of the thenar and hypothenar eminences. Palmer
[15] was the first to describe a type 2 fracture of the tubercle of the trapezium. Fractures of the hook of the hamate, which often occur in combination with pisiform fractures, have also been reported during violent muscle contractions [1,16]. This fracture occurs most often in young male athletes. The clinical picture is that of a persistent wrist sprain that mainly manifests itself during wrist movements, such as when the patient tries to catch a ball or makes a fist, thereby restricting the athlete from sports participation. The pain can be reproduced by directly pressing on the hook of the hamate [5]. Nevertheless, patients may not experience any pain because of the padding provided by the hypothenar area. Edema may be present in the acute phase of the injury [8]. Given that the hook of the hamate acts as a simple pulley for the FDP tendon of the little finger, distinct pain can be triggered upon flexion of the little finger across the hand, while placing the wrist in ulnar deviation. When the injury becomes chronic, the unhealed bone fragments can sever the flexor tendons of the ring and little finger. A patient will have early signs of flexor tendinopathy in the little finger [5]. In some cases, shifting of the bone fragments can irritate neighboring nerve structures. Some cases of entrapment neuropathy have been reported, mainly involving the ulnar nerve, but also the median nerve [17,18]. It is not rare for the diagnosis of hamate fracture to be made belatedly when faced with these complications [8]. The incidence of tendon injuries associated with hook of the hamate fractures is estimated to be 17% [9]. Nevertheless, differential diagnoses must be eliminated when faced with DIP flexion deficit, namely pisotriquetral osteoarthritis [19], trigger finger with distinct pain on the A1 pulley, along with FDP rupture at its distal insertion (Jersey finger).
J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
47
Fig. 4. Surgical treatment: Brunner incision over the non-union site (A). Dissection of the hypothenar eminence and ulnar pedicle (B). Exposure of the non-union site (C). Resection of the hook of the hamate (D). Distal stump of ruptured FDP tendon of the little finger; the FDS tendon is intact (E).
Standard radiographs with orthogonal views will not be useful in making the diagnosis of hook of the hamate fracture or non-union. Carpal tunnel and 3/4 views with 458 supination and radial deviation are recommended instead. Yamazaki et al. [7] found this fracture in two of four patients who had an oblique lateral view with the wrist supinated and five of five patients who had carpal tunnel views. On the other hand, CT scan images always provide evidence to support the diagnosis. Ultrasonography and MRI are useful in identifying ligament damage. However, MRI cannot be used to eliminate the possibility of non-union [7]. Additional examinations such as EMG are not needed unless there are associated nerve complications.
Typical surgical treatment consists of resecting the hook portion of the hamate when non-union is present. Watson et al. [20] prefer to fix the fragment after freshening of the site/ grafting so as to preserve the hook’s pulley capacity for the flexor tendons of the little finger. More recently, some teams have proposed new fixation methods, namely the use of a hookplate [21] or the use of a cannulated screw through a dorsal percutaneous approach [22]. In most cases, the tendon injuries are repaired during the same procedure. In cases with tendon retraction or defect after trimming the ruptured tendon ends, various techniques have been used: tendon graft [3–7], FDS transfer from the ring finger [23] or end-to-side suture of the distal stump of the fifth FDP
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J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
References
Fig. 5. Results of the tenodesis of the FDP stump in the little finger to its FDS tendon (A). Immediate recovery of the tenodesis grasp for the little finger (B).
tendon to the fourth FDP tendon [9]. Recently, Jeong et al. [24] presented a case of hook of the hamate non-union leading to FDP and FDS tendon rupture in the ring and little finger; the tendon repair was performed in two stages. No matter which technique is used, the outcomes were satisfactory. 4. Conclusion Fractures of the hook of the hamate often go unrecognized. Although rare, they can lead to non-trivial tendon complications. It is important to look for this injury in every case of acute wrist trauma. The clinician must also eliminate the possibility of hook of the hamate non-union when a patient presents with tendinopathy or spontaneous rupture of the flexor tendons in the little finger, especially if there are associated signs of irritation in neighboring structures, such as flexor tendinopathy in the ring finger and entrapment neuropathy. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
[1] Andress MR, Peckar VG. Fracture of the hook of the hamate. Br J Radiol 1970;43:141–3. [2] Nisenfield FG, Neviaser RJ. Fracture of the hook of the hamate: a diagnosis easily missed. J Trauma 1974;14:612–6. [3] Teissier J, Escare P, Asencio G, Gomis R, Allieu Y. Rupture of the flexor tendons of the little finger in fractures of the hook of the hamate bone. Reprint of two cases. Ann Chir Main 1983;2:319–27. [4] Carter PR, Eaton RG, Littler JW. Ununited fracture of the hook of the hamate. J Bone Joint Surg Am 1977;59:583–8. [5] Stark HH, Jobe FW, Boyes JH, Ashworth CR. Fractures of the hook of the hamate in athletes. J Bone Joint Surg Am 1977;59:575–82. [6] Kamina P. 4e éd., Précis d’anatomie clinique, 1, 4e éd. Paris: Maloine; 2005. [7] Yamazaki H, Kato H, Nakatsuchi Y, Murakami N, Hata Y. Closed rupture of the flexor tendon of the little finger secondary to non-union of the hook of the hamate. J Hand Surg Br 2006;31:337–41. [8] Foucher G, Schuind F, Merle M, Brunelli F. Fracture of the hook of the hamate. J Hand Surg Br 1985;10:205–10. [9] Milek MA, Boulas HJ. Flexor tendon ruptures secondary to hamate hook fractures. J Hand Surg Am 1990;15:740–4. [10] Pajares-López M, Hernández-Cortés P, Robles-Molina MJ. Rupture of small finger flexor tendons secondary to asymptomatic non-union of the hamate hook. Orthopedics 2011;34:142. [11] Hartford JM, Murphy JM. Flexor digitorum profundus rupture of the small finger secondary to non-union of the hook of hamate: a case report. J Hand Surg Am 1996;21:621–3. [12] Minami A, Ogino T, Usui M, Ishii S. Finger tendon rupture secondary to fracture of the hamate. A case report. Acta Orthop Scand 1985;56:96–7. [13] Takami H, Takahashi S, Ando M. Rupture of flexor tendon associated with previous fracture of the hook of the hamate. Hand 1983;15:73–6. [14] Yang SS, Kalainov DM, Weiland AJ. Fracture of the hook of hamate with rupture of the flexor tendons of the small finger in a rheumatoid patient: a case report. J Hand Surg Am 1996;21:916–7. [15] Palmer AK. Trapezial ridge fractures. J Hand Surg Am 1981;6:561–4. [16] Murray WT, Meuller PR, Rosenthal DI, Jauernek RR. Fracture of the hook of the hamate. AJR Am J Roentgenol 1979;133:899–903. [17] Sugawara O, Katayama K, Togiya S. Fracture of the hamate hook presenting as median nerve palsy. Arch Orthop Trauma Surg 1998;117: 173–4. [18] Shea JD, McClain EJ. Ulnar nerve compression syndromes at and below the wrist. J Bone Joint Surg Am 1969;51:1095–103. [19] Saitoh S, Kitagawa E, Hosaka M. Rupture of flexor tendons due to pisotriquetral osteoarthritis. Arch Orthop Trauma Surg 1997;116:303–6. [20] Watson HK, Rogers WD. Non-union of the hook of the hamate: an argument for bone grafting the non-union. J Hand Surg Am 1989;14: 486–90. [21] Taleb C, Murachowsky J, Ruggiero GM. Hamate hook non-union treated with a hook plate: case report and surgical technique. Tech Hand Up Ext Surg 2012;16:194–7. [22] Scheufler O, Radmer S, Andresen R. Dorsal percutaneous cannulated mini-screw fixation for fractures of the hamate hook. Hand Surg 2012;17:287–93. [23] Jackson T, Rayan GM. Avulsion fracture of the hamulus from clay gunshot sport: a case report. J Hand Surg Am 2005;30:702–5. [24] Jeong SH, Gu JH, Han SK, Kim WK. Two-staged tendon reconstruction in flexor tendon ruptures secondary to fracture of the hamate hook. Ann Plast Surg 2012;69:157–60.
ScienceDirect www.sciencedirect.com Chirurgie de la main 34 (2015) 44–48
Clinical case
Tendon rupture of the flexor digitorum profundus of the little finger secondary to hamate non-union Pseudarthrose de l’hamulus de l’hamatum responsable d’une rupture de tendon fléchisseur profond du cinquième rayon J. Gaillard a,*, S. Roy-Maillot a, E.-H. Masmejean b a
Service de chirurgie orthopédique et traumatologique & SOS main, hôpital Saint-Antoine, 184, rue du Faubourg-Saint-Antoine, 75571 Paris cedex 12, France b Service de chirurgie orthopédique et traumatologique & SOS main, hôpital européen Georges-Pompidou, 20, rue Leblanc, 75908 Paris cedex 15, France Received 31 May 2014; received in revised form 1 October 2014; accepted 5 October 2014 Available online 8 December 2014
Abstract 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. # 2014 Elsevier Masson SAS. All rights reserved. Keywords: Carpus; Non-union; Hamate; Flexor tendon; Rupture
Résumé Plusieurs cas de fractures et pseudarthroses de l’hamatum ont été rapportés. Son hamulus agit comme une poulie de réflexion pour les tendons fléchisseurs des cinquième et quatrième rayons. Les pseudarthroses de l’hamulus de l’hamatum sont souvent associées à un syndrome irritatif des structures adjacentes. Nous rapportons le cas d’un patient présentant une pseudarthrose de la base de l’hamulus de l’hamatum, diagnostiquée à distance devant une rupture du tendon fléchisseur profond du cinquième doigt, associée à une tendinopathie des deux tendons fléchisseurs du quatrième doigt. # 2014 Elsevier Masson SAS. Tous droits réservés. Mots clés : Carpe ; Pseudarthrose ; Hamatum ; Tendon fléchisseur ; Rupture
1. Introduction Carpal bones fractures are common and mainly affect the scaphoid; the other carpal bones are not fractured as often. Hamate fractures only make up 2% of carpal fractures [1,2]. Fractures of the hook-like process of the hamate (hamulus) are
* Corresponding author. E-mail address: [email protected] (J. Gaillard). http://dx.doi.org/10.1016/j.main.2014.10.147 1297-3203/# 2014 Elsevier Masson SAS. All rights reserved.
rare. Tessier et al. identified 42 published cases in 1983 [3]. The most common complications were injuries to the neighboring flexor tendons (ring and little finger). Cases of irritation of adjacent nerve pedicles (ulnar and median) have been described on rare occasions, leading to entrapment neuropathy in certain cases. This article reports the case of a patient who was diagnosed with hook of the hamate non-union only after finding a ruptured flexor digitorum profundus (FDP) tendon in the little finger and signs of flexor tendinopathy in the ring finger. The diagnosis was made 4 years after the initial injury event.
J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
45
2. Case report This was a 57-year-old, right-handed male patient who did not smoke and had no significant medical history. The clinical history went back to 2009, at which point the patient suffered an injury to his left hand while working with a tool. The patient had been treated with courses of non-steroidal anti-inflammatory drugs. Due to persistent pain, he consulted with a rheumatologist who twice injected corticosteroids into the metacarpophalangeal joint of the little finger; this provided transient pain relief but did not help him regain his strength. In March 2013, ultrasonography revealed tenosynovitis of the flexor tendons in the little finger. A/P and lateral radiographs were normal (Fig. 1A, B). An electromyogram (EMG) confirmed there was no peripheral nerve injury. He had been on sick leave for 3 months when he was referred to us. Clinically, the patient had carpal pain during passive finger curling, which was reproduced by specifically palpating the volar side of the hamate. The passive range of motion of the finger joints was complete and painless. There was reduced active flexion of the distal interphalangeal (DIP) joint of the little finger, which the patient indicated was present before the corticosteroid injections (Fig. 2A), and loss of tenodesis grasp with absence of flexion in the fifth DIP joint (Fig. 2B) during wrist extension. His average muscle strength measured on a Jamar dynamometer was 38 kg for the right hand and 18 kg for the left. A second ultrasonography exam revealed a rupture of the FDP tendon in the little finger with the proximal stump retracted to the distal volar wrist crease and the distal stump located at the shaft of the fifth metacarpal. CT scan revealed a non-union at the base of the hook of the hamate, with small subchondral cysts on both sides, but without osteophytes or condensation. The flexor tendons of the little finger and the FDP of the ring finger pass along the lateral side of this non-union (Fig. 3A). Magnetic resonance imaging (MRI) revealed additional injuries: tendinopathy of the flexor digitorum superficialis (FDS) of the little finger, tendinopathy of the FDP and FDS of the ring finger and subchondral cysts in the medial part of the head of the capitate (Fig. 3B–D). Surgical treatment was performed on an outpatient basis with regional anesthesia and a tourniquet. The approach consisted of a Brunner zigzag incision over the non-union site
Fig. 1. A/P (A) and lateral (B) radiographs of the wrist.
(Fig. 4A). The hypothenar eminence and carpal tunnel were opened to assess the extent of the damage (Fig. 4B). Non-union at the base of the hook of the hamate was confirmed (Fig. 4C). The FDP tendon in the little finger had ruptured, while the FDP tendon in the ring finger was inflamed but still intact. There were visible signs of inflammatory tendinopathy. The hook of the hamate was excised and the non-union site was leveled to prevent the tendon from being damaged when it rubs against the remainder of the hook’s base (Fig. 4D). The distal stump of the torn FDP was retrieved at the base of the fifth metacarpal and the proximal stump was retracted to the wrist and left in place (Fig. 4E). Because of the excessively large tendon defect, tenodesis of the distal stump of the torn FDP tendon to the FDS tendon was carried out by direct suture with a physiologically tensioned Pulvertaft weave (Fig. 5A, B). The repaired tendon was protected with a Duran brace for six weeks, which allowed for immediate protected mobilization. 3. Discussion The hamate has a hook-like process called the hamulus. This process is thin and elongated. The hook of the hamate can be palpated 1.5 to 2 cm distal to the pisiform on an angled line drawn from the pisiform bone and the head of the second metacarpal [4]. It can be compared to the mast of a ship, to which the transverse carpal ligament and pisohamate ligament
Fig. 2. Active flexion deficit of the DIP in the little finger (A) and loss of tenodesis grasp of the DIP in the same finger (B).
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Fig. 3. CT scan reveals non-union at the base of the hook of the hamate, with small subchondral cysts on both sides (A). T1-weighted axial MRI slice showing tendinopathy of the FDP tendon of the ring finger and empty sheaths of the little finger over the fracture site (B). T1-weighted axial MRI slice showing tendinopathy of the FDP tendon of the ring finger and the proximal stump of the ruptured FDP in the little finger (C). T2-weight axial MRI slice of the metacarpal shafts showing the distal stump of the ruptured FDP tendon in the little finger and FDP tendinopathy in the ring finger (D).
are attached; this extends the distal tendon of the flexor carpi ulnaris, which has a hammock shape, and makes up the floor of Guyon’s canal [5,6]. The radial aspect of the hook acts as the medial margin of the carpal tunnel. The two-flexor tendons of the little finger bend around its concave surface. Its ulnar aspect forms the lateral edge of Guyon’s canal [6]. During finger flexion with the wrist in ulnar deviation, the FDP tendon of the little finger bends around a trochlea formed by the radial edge of the hook of the hamate [4]. The hook of the hamate can fracture in three locations: base, body and tip. In the patient described here, the fracture was located at the base. This is the most common type of fracture described in published studies. Stark et al. found that 47 out of 62 patients had a base fracture [5]. Of the 27 cases of flexor tendon rupture due to non-union of the hook of the hamate, the exact fracture site was only reported in eight studies [7–14]. Contrary to the findings of Pajares-López et al. [10], the hook of the hamate is fractured most often at its base [5]. The location of the non-union does not seem to be related the flexor tendon rupture [7]. The most common fracture mechanism is a direct impact to the hook itself [2–5,8]. This can occur after a patient falls and lands on the hypothenar side of the carpus or more typically, in those who participate in sports such as golf, squash, tennis or baseball. These sports all require use of a club, racket or bat where the distal stump of the handle presses against the ulnar side of the hook of the hamate. The handle is held in the dominant hand by a tennis player, but in the non-dominant hand by golfers and batters [5]. More rarely, the fracture occurs indirectly by traction on the flexor retinaculum, which stretches to either side of the thenar and hypothenar eminences. Palmer
[15] was the first to describe a type 2 fracture of the tubercle of the trapezium. Fractures of the hook of the hamate, which often occur in combination with pisiform fractures, have also been reported during violent muscle contractions [1,16]. This fracture occurs most often in young male athletes. The clinical picture is that of a persistent wrist sprain that mainly manifests itself during wrist movements, such as when the patient tries to catch a ball or makes a fist, thereby restricting the athlete from sports participation. The pain can be reproduced by directly pressing on the hook of the hamate [5]. Nevertheless, patients may not experience any pain because of the padding provided by the hypothenar area. Edema may be present in the acute phase of the injury [8]. Given that the hook of the hamate acts as a simple pulley for the FDP tendon of the little finger, distinct pain can be triggered upon flexion of the little finger across the hand, while placing the wrist in ulnar deviation. When the injury becomes chronic, the unhealed bone fragments can sever the flexor tendons of the ring and little finger. A patient will have early signs of flexor tendinopathy in the little finger [5]. In some cases, shifting of the bone fragments can irritate neighboring nerve structures. Some cases of entrapment neuropathy have been reported, mainly involving the ulnar nerve, but also the median nerve [17,18]. It is not rare for the diagnosis of hamate fracture to be made belatedly when faced with these complications [8]. The incidence of tendon injuries associated with hook of the hamate fractures is estimated to be 17% [9]. Nevertheless, differential diagnoses must be eliminated when faced with DIP flexion deficit, namely pisotriquetral osteoarthritis [19], trigger finger with distinct pain on the A1 pulley, along with FDP rupture at its distal insertion (Jersey finger).
J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
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Fig. 4. Surgical treatment: Brunner incision over the non-union site (A). Dissection of the hypothenar eminence and ulnar pedicle (B). Exposure of the non-union site (C). Resection of the hook of the hamate (D). Distal stump of ruptured FDP tendon of the little finger; the FDS tendon is intact (E).
Standard radiographs with orthogonal views will not be useful in making the diagnosis of hook of the hamate fracture or non-union. Carpal tunnel and 3/4 views with 458 supination and radial deviation are recommended instead. Yamazaki et al. [7] found this fracture in two of four patients who had an oblique lateral view with the wrist supinated and five of five patients who had carpal tunnel views. On the other hand, CT scan images always provide evidence to support the diagnosis. Ultrasonography and MRI are useful in identifying ligament damage. However, MRI cannot be used to eliminate the possibility of non-union [7]. Additional examinations such as EMG are not needed unless there are associated nerve complications.
Typical surgical treatment consists of resecting the hook portion of the hamate when non-union is present. Watson et al. [20] prefer to fix the fragment after freshening of the site/ grafting so as to preserve the hook’s pulley capacity for the flexor tendons of the little finger. More recently, some teams have proposed new fixation methods, namely the use of a hookplate [21] or the use of a cannulated screw through a dorsal percutaneous approach [22]. In most cases, the tendon injuries are repaired during the same procedure. In cases with tendon retraction or defect after trimming the ruptured tendon ends, various techniques have been used: tendon graft [3–7], FDS transfer from the ring finger [23] or end-to-side suture of the distal stump of the fifth FDP
48
J. Gaillard et al. / Chirurgie de la main 34 (2015) 44–48
References
Fig. 5. Results of the tenodesis of the FDP stump in the little finger to its FDS tendon (A). Immediate recovery of the tenodesis grasp for the little finger (B).
tendon to the fourth FDP tendon [9]. Recently, Jeong et al. [24] presented a case of hook of the hamate non-union leading to FDP and FDS tendon rupture in the ring and little finger; the tendon repair was performed in two stages. No matter which technique is used, the outcomes were satisfactory. 4. Conclusion Fractures of the hook of the hamate often go unrecognized. Although rare, they can lead to non-trivial tendon complications. It is important to look for this injury in every case of acute wrist trauma. The clinician must also eliminate the possibility of hook of the hamate non-union when a patient presents with tendinopathy or spontaneous rupture of the flexor tendons in the little finger, especially if there are associated signs of irritation in neighboring structures, such as flexor tendinopathy in the ring finger and entrapment neuropathy. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
[1] Andress MR, Peckar VG. Fracture of the hook of the hamate. Br J Radiol 1970;43:141–3. [2] Nisenfield FG, Neviaser RJ. Fracture of the hook of the hamate: a diagnosis easily missed. J Trauma 1974;14:612–6. [3] Teissier J, Escare P, Asencio G, Gomis R, Allieu Y. Rupture of the flexor tendons of the little finger in fractures of the hook of the hamate bone. Reprint of two cases. Ann Chir Main 1983;2:319–27. [4] Carter PR, Eaton RG, Littler JW. Ununited fracture of the hook of the hamate. J Bone Joint Surg Am 1977;59:583–8. [5] Stark HH, Jobe FW, Boyes JH, Ashworth CR. Fractures of the hook of the hamate in athletes. J Bone Joint Surg Am 1977;59:575–82. [6] Kamina P. 4e éd., Précis d’anatomie clinique, 1, 4e éd. Paris: Maloine; 2005. [7] Yamazaki H, Kato H, Nakatsuchi Y, Murakami N, Hata Y. Closed rupture of the flexor tendon of the little finger secondary to non-union of the hook of the hamate. J Hand Surg Br 2006;31:337–41. [8] Foucher G, Schuind F, Merle M, Brunelli F. Fracture of the hook of the hamate. J Hand Surg Br 1985;10:205–10. [9] Milek MA, Boulas HJ. Flexor tendon ruptures secondary to hamate hook fractures. J Hand Surg Am 1990;15:740–4. [10] Pajares-López M, Hernández-Cortés P, Robles-Molina MJ. Rupture of small finger flexor tendons secondary to asymptomatic non-union of the hamate hook. Orthopedics 2011;34:142. [11] Hartford JM, Murphy JM. Flexor digitorum profundus rupture of the small finger secondary to non-union of the hook of hamate: a case report. J Hand Surg Am 1996;21:621–3. [12] Minami A, Ogino T, Usui M, Ishii S. Finger tendon rupture secondary to fracture of the hamate. A case report. Acta Orthop Scand 1985;56:96–7. [13] Takami H, Takahashi S, Ando M. Rupture of flexor tendon associated with previous fracture of the hook of the hamate. Hand 1983;15:73–6. [14] Yang SS, Kalainov DM, Weiland AJ. Fracture of the hook of hamate with rupture of the flexor tendons of the small finger in a rheumatoid patient: a case report. J Hand Surg Am 1996;21:916–7. [15] Palmer AK. Trapezial ridge fractures. J Hand Surg Am 1981;6:561–4. [16] Murray WT, Meuller PR, Rosenthal DI, Jauernek RR. Fracture of the hook of the hamate. AJR Am J Roentgenol 1979;133:899–903. [17] Sugawara O, Katayama K, Togiya S. Fracture of the hamate hook presenting as median nerve palsy. Arch Orthop Trauma Surg 1998;117: 173–4. [18] Shea JD, McClain EJ. Ulnar nerve compression syndromes at and below the wrist. J Bone Joint Surg Am 1969;51:1095–103. [19] Saitoh S, Kitagawa E, Hosaka M. Rupture of flexor tendons due to pisotriquetral osteoarthritis. Arch Orthop Trauma Surg 1997;116:303–6. [20] Watson HK, Rogers WD. Non-union of the hook of the hamate: an argument for bone grafting the non-union. J Hand Surg Am 1989;14: 486–90. [21] Taleb C, Murachowsky J, Ruggiero GM. Hamate hook non-union treated with a hook plate: case report and surgical technique. Tech Hand Up Ext Surg 2012;16:194–7. [22] Scheufler O, Radmer S, Andresen R. Dorsal percutaneous cannulated mini-screw fixation for fractures of the hamate hook. Hand Surg 2012;17:287–93. [23] Jackson T, Rayan GM. Avulsion fracture of the hamulus from clay gunshot sport: a case report. J Hand Surg Am 2005;30:702–5. [24] Jeong SH, Gu JH, Han SK, Kim WK. Two-staged tendon reconstruction in flexor tendon ruptures secondary to fracture of the hamate hook. Ann Plast Surg 2012;69:157–60.
