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Flexor digitorum profundus rupture of the small finger secondary to nonunion of the hook of hamate: A case report
Flexor Digitorum Profundus Rupture of the Small Finger Secondary to Nonunion of the Hook of Hamate: A Case Report JamesM. Hartford, MD, JamesM. Murphy, MD, Lebanon, NH
Sponlaneous rupture of the flexor tendons generally occurs because of weakening of the tendon due to a pathologic process) Complete rupture of the flexor digitorum profandus (FDP) of the small finger due to a nonunion of the hook of hamate is a rare injury. To ot~r knowledge, there have been only nine cases reported in the English literature. We present an additional case, which illustrates the evaluation and treatment of a spontaneous rupture of a flexor tendon, including magnetic resonance imaging and examination of x-ray films. A review of the recent literature is also presented.
Case Report A 49-year-old right-hand-dominant man noted a month prior to presentation that he was unable to flex the little finger of his left hand. The patient works as a lathe operator and was unable to account for any recent or remote history of trauma. He did not have any prior steroid injections. He claimed to be otherwise healthy. On evaluation, the patient was unable to flex either the distal or proximal interphalangeal joints of the left little finger, but did not have any pain or local tenderness about the hand. No masses were palpable in the palm. Routine x-ray
From Lhe Section o• Orthopaedic SurgeD; Depa~ment of Surgery, Dartmouth Hitehcock Medical Center, l.ebmm~, NH. Received for pablJcatio~ March 23, 1995; accepted in rev'ised form Dec. 5, 1995. No benefits in any form have been recdved or will be lvce~ved from commercial party rented directly or indirecdy to the subject of this article~ Reprint requests: .I-runes M. Mmphy, MD, Section of Orthopaedic Surgery, Depm'tment o[" Sargery, Dartmot~th Hiteheook Medical Center, Lebanot~, ~ 03756.
fi Ires from the referring physician provided no diagnostic clues. The clinical history and findings of the physical examination were dissonant, and this prompted a magnetic resonance imaging (MRI) scan. Magnetic resonance imaging revealed a rupture of the EDP of the little linger (Fig. 1) and a corticared bony ossicle at the level o f the hook of hamate consistent with a bony nonunion of the hook (Fig. 2). With the dissonance of the clinical history and physical examination findings, the diagnosis was not clear. The MRI helped to clarify the site of rupture, the etiology, and the treatment options. A subsequent carpal tunnel vicw farther defined a nonunion of the hook of hamate (Fig. 3). The patient underwent release of the carpal tunnel and Guyon's canal followed by exploration o f the flexor tendons of the little finger. The nonunion of the hook of hamate was identified and the bony ossicle excised. The FDP and the flexor digitorum superficialis to the small finger were both ruptured. The flexor tendons to the ring finger were not involved, The flexor digitorum superficialis of the ring finger was u-ansferred to the FDP of the little finger, At the 8-month follow-up examination, the patient had normal sensation and was able to actively flex his small finger to within 1 cm of his distal palmar crease. He returned to his regular occupation within 4 months without restriction.
Discussion To our knowledge, there are only nine cases of complete tendon rupture due to a fi:acture of the hook of hamate reported in the English literature 1-7 (Table t). In two cases, the specific tendons involved Thejourna[ of Hand Surgery 621
622
Harff~rd and Murphy/FDP Rupture and Nonunion of Hook of Hamate
Figure 2. Magnetic resonance image of the hook of hamate nonunion.
Figure 1, Magnetic resonance image of the ruptured flexor digitorum profundus of the little finger. Note the absence of tendon ;)n one of two cuts.
were n o t identified. 3 Six o f the c a s e s involved the .FDP tendon o f the ill.fie linger. O f these six cases, five were related directly to the nonunion o f the hook o f hamate, and in one case the patient had received steroid injectiolls into the r e g i o n o f the tendon p r i o r to rupture. F l e x o r tendon rupt.ures due to h o o k o f h a m a t e fractures typically inw)lve the ring and little finger. A larger n u m b e r o f litlle-linger tend.ons involved is related to the finger's p r o x i m i t y to the h o o k o f hamate, T h e e t i o l o g y o f the attritional rupture o f the flexor tendons has b e e n a t m b u t e d to the r o u g h b o n y
Figure 3. C ~ p a l runnel vicw of the hook of hamatc.
surfaces o f the fractured h o o k o f hamate. "~-s-7Several authors r e c o m m e n d excision o f the h o o k of hamate, f o l l o w e d b y rcconstitution o f p r o f u n d u s f u n c t k m to the involved finger?, s S t a r k et al, advocate e x c i s i o n
l h b l e 1. Spontaneous Tendon Rupture Secondary to Hook o f Hamate Fracture Auzhor(s)
N~. Patients"
Tendons Involved
Steroid Injection
Fracture 7~eatment
Tendon Treatmenf
Bishop and Beckenbaugh 2 Boyes et al.J
1
FDS V, FDP V
No
1"
'1"
1
No
"l"
'l"
Clayton.~ Crosby and Linscheid4 Minami et al.s
2 2
FDP IV, b'DS V, FDI' V Patients 1 &2: FDR FDS Patient 1: FDP IV Patient 2: FDS V, FDP V FDP V
No No
]Direct repair
Stark et al. 6,7.
2
]Excision of bony fragment Excision of bony fragment Excision ef bony fiagment
[
Patient l : FDS IV, FDP IV.. I-'DSV, bDP V Patient 2: FDS IV. FDS V, FDP V
No Yes, in patient I
*Patient 1 described in both references. q~Treatment ncg describe& FD]; flexor digitorum pmfundus; FDS, flexor digitorum superficialis.
FDS of 2ing finger to FDP of li;tie finger Tendon graft
The Iournal of ] land Surgery / Vol, 21A No. 4 Ju[y 1996
of the fragment even in asymptomatic patients in whom the fracture is discovered by an x-ray fihn examination obtained for other reasons? Ours is the seventh case of FDP rupture of the little finger due to fi'acture of the hook of hamate. The patient did ~ot have any prodromal symptoms sugges rive of tenosynovitis, which the literature suggests is often present. Magnetic resonance imaging and a c~wpal tunnel view x-ray film reveMed the site mad etiology of rupture. With an exact diagnosis, u-eatment options were clarified. A trm~sfer of the flexor digitorum superficialis of the ling finger to the I-'DP of the small finger has been recommended in the literature and was performed in our patient, Primary repair, if possible, and free tendon graft reconstructkm are also recognized as two viable alternatives?, 7 This report illuslratcs the benefit of magnetic resonance imaging and carpal tunnel view x-ray films in the evaluation (ff spontaneous flexor tendon ruptures in certain cases. In those cases in which fracture of the hook of hamate is the cause of the rupture, excision of the osseous fragment with smoothing of the rough bony surfaces is uniformly recommended.
623
Restorauon of FDP funclion to the affected finger is then performed, with uniformly good results,
References I. Be)yesJH, Wilson :IN, Smith JW. Flexor tendon ruptttrcs in [he ft~rearm and hand. J Bone Joint Snrg 1960;42A: 637-4~46. 2. Bishop AT, Beckenbaugh RD. Fracture of the hamate t~ook, J Hand Surg 1988;13A:135-139. 3. CLaytonML. Rupture of the flexortendons in the carpal tunnel (nonrheumatoid) with specific rc~izrence to fracture uf the hook uf tlae Hmnatc. J Bone Joint Surg t969;5 IA:798--799. 4. Crosby EB, Linsheid RI,. Rupture of the flexor profundus tertdon of the ring linger secondary to ancient fractme of the hook of the H:~mate: review cff the literature and report of two cases. J Bone Joint Surg 1974;56A:1076-1078. 5. Mhlami A, Ogino T, Usui M, lshii S. Finger tendon rupture secoMary to fi-acture of the Hmnate. Acta Orthop Seand 1985;56:96-97. 6. Stark HI-I, Chat E, Zeme NP, Rickard TA, Ashworth CR. Fracture of the hook of the Hamate. J BorneJ o l t Su• 1989; 71A:1202--1207. 7. Stark HH, Jobe FW, Boyes JH, Ashworth CR. Fractm'e of the hook of the Hamate in athletes. J Bone Joint Surg 1977; 59A:S75-582.
Sponlaneous rupture of the flexor tendons generally occurs because of weakening of the tendon due to a pathologic process) Complete rupture of the flexor digitorum profandus (FDP) of the small finger due to a nonunion of the hook of hamate is a rare injury. To ot~r knowledge, there have been only nine cases reported in the English literature. We present an additional case, which illustrates the evaluation and treatment of a spontaneous rupture of a flexor tendon, including magnetic resonance imaging and examination of x-ray films. A review of the recent literature is also presented.
Case Report A 49-year-old right-hand-dominant man noted a month prior to presentation that he was unable to flex the little finger of his left hand. The patient works as a lathe operator and was unable to account for any recent or remote history of trauma. He did not have any prior steroid injections. He claimed to be otherwise healthy. On evaluation, the patient was unable to flex either the distal or proximal interphalangeal joints of the left little finger, but did not have any pain or local tenderness about the hand. No masses were palpable in the palm. Routine x-ray
From Lhe Section o• Orthopaedic SurgeD; Depa~ment of Surgery, Dartmouth Hitehcock Medical Center, l.ebmm~, NH. Received for pablJcatio~ March 23, 1995; accepted in rev'ised form Dec. 5, 1995. No benefits in any form have been recdved or will be lvce~ved from commercial party rented directly or indirecdy to the subject of this article~ Reprint requests: .I-runes M. Mmphy, MD, Section of Orthopaedic Surgery, Depm'tment o[" Sargery, Dartmot~th Hiteheook Medical Center, Lebanot~, ~ 03756.
fi Ires from the referring physician provided no diagnostic clues. The clinical history and findings of the physical examination were dissonant, and this prompted a magnetic resonance imaging (MRI) scan. Magnetic resonance imaging revealed a rupture of the EDP of the little linger (Fig. 1) and a corticared bony ossicle at the level o f the hook of hamate consistent with a bony nonunion of the hook (Fig. 2). With the dissonance of the clinical history and physical examination findings, the diagnosis was not clear. The MRI helped to clarify the site of rupture, the etiology, and the treatment options. A subsequent carpal tunnel vicw farther defined a nonunion of the hook of hamate (Fig. 3). The patient underwent release of the carpal tunnel and Guyon's canal followed by exploration o f the flexor tendons of the little finger. The nonunion of the hook of hamate was identified and the bony ossicle excised. The FDP and the flexor digitorum superficialis to the small finger were both ruptured. The flexor tendons to the ring finger were not involved, The flexor digitorum superficialis of the ring finger was u-ansferred to the FDP of the little finger, At the 8-month follow-up examination, the patient had normal sensation and was able to actively flex his small finger to within 1 cm of his distal palmar crease. He returned to his regular occupation within 4 months without restriction.
Discussion To our knowledge, there are only nine cases of complete tendon rupture due to a fi:acture of the hook of hamate reported in the English literature 1-7 (Table t). In two cases, the specific tendons involved Thejourna[ of Hand Surgery 621
622
Harff~rd and Murphy/FDP Rupture and Nonunion of Hook of Hamate
Figure 2. Magnetic resonance image of the hook of hamate nonunion.
Figure 1, Magnetic resonance image of the ruptured flexor digitorum profundus of the little finger. Note the absence of tendon ;)n one of two cuts.
were n o t identified. 3 Six o f the c a s e s involved the .FDP tendon o f the ill.fie linger. O f these six cases, five were related directly to the nonunion o f the hook o f hamate, and in one case the patient had received steroid injectiolls into the r e g i o n o f the tendon p r i o r to rupture. F l e x o r tendon rupt.ures due to h o o k o f h a m a t e fractures typically inw)lve the ring and little finger. A larger n u m b e r o f litlle-linger tend.ons involved is related to the finger's p r o x i m i t y to the h o o k o f hamate, T h e e t i o l o g y o f the attritional rupture o f the flexor tendons has b e e n a t m b u t e d to the r o u g h b o n y
Figure 3. C ~ p a l runnel vicw of the hook of hamatc.
surfaces o f the fractured h o o k o f hamate. "~-s-7Several authors r e c o m m e n d excision o f the h o o k of hamate, f o l l o w e d b y rcconstitution o f p r o f u n d u s f u n c t k m to the involved finger?, s S t a r k et al, advocate e x c i s i o n
l h b l e 1. Spontaneous Tendon Rupture Secondary to Hook o f Hamate Fracture Auzhor(s)
N~. Patients"
Tendons Involved
Steroid Injection
Fracture 7~eatment
Tendon Treatmenf
Bishop and Beckenbaugh 2 Boyes et al.J
1
FDS V, FDP V
No
1"
'1"
1
No
"l"
'l"
Clayton.~ Crosby and Linscheid4 Minami et al.s
2 2
FDP IV, b'DS V, FDI' V Patients 1 &2: FDR FDS Patient 1: FDP IV Patient 2: FDS V, FDP V FDP V
No No
]Direct repair
Stark et al. 6,7.
2
]Excision of bony fragment Excision of bony fragment Excision ef bony fiagment
[
Patient l : FDS IV, FDP IV.. I-'DSV, bDP V Patient 2: FDS IV. FDS V, FDP V
No Yes, in patient I
*Patient 1 described in both references. q~Treatment ncg describe& FD]; flexor digitorum pmfundus; FDS, flexor digitorum superficialis.
FDS of 2ing finger to FDP of li;tie finger Tendon graft
The Iournal of ] land Surgery / Vol, 21A No. 4 Ju[y 1996
of the fragment even in asymptomatic patients in whom the fracture is discovered by an x-ray fihn examination obtained for other reasons? Ours is the seventh case of FDP rupture of the little finger due to fi'acture of the hook of hamate. The patient did ~ot have any prodromal symptoms sugges rive of tenosynovitis, which the literature suggests is often present. Magnetic resonance imaging and a c~wpal tunnel view x-ray film reveMed the site mad etiology of rupture. With an exact diagnosis, u-eatment options were clarified. A trm~sfer of the flexor digitorum superficialis of the ling finger to the I-'DP of the small finger has been recommended in the literature and was performed in our patient, Primary repair, if possible, and free tendon graft reconstructkm are also recognized as two viable alternatives?, 7 This report illuslratcs the benefit of magnetic resonance imaging and carpal tunnel view x-ray films in the evaluation (ff spontaneous flexor tendon ruptures in certain cases. In those cases in which fracture of the hook of hamate is the cause of the rupture, excision of the osseous fragment with smoothing of the rough bony surfaces is uniformly recommended.
623
Restorauon of FDP funclion to the affected finger is then performed, with uniformly good results,
References I. Be)yesJH, Wilson :IN, Smith JW. Flexor tendon ruptttrcs in [he ft~rearm and hand. J Bone Joint Snrg 1960;42A: 637-4~46. 2. Bishop AT, Beckenbaugh RD. Fracture of the hamate t~ook, J Hand Surg 1988;13A:135-139. 3. CLaytonML. Rupture of the flexortendons in the carpal tunnel (nonrheumatoid) with specific rc~izrence to fracture uf the hook uf tlae Hmnatc. J Bone Joint Surg t969;5 IA:798--799. 4. Crosby EB, Linsheid RI,. Rupture of the flexor profundus tertdon of the ring linger secondary to ancient fractme of the hook of the H:~mate: review cff the literature and report of two cases. J Bone Joint Surg 1974;56A:1076-1078. 5. Mhlami A, Ogino T, Usui M, lshii S. Finger tendon rupture secoMary to fi-acture of the Hmnate. Acta Orthop Seand 1985;56:96-97. 6. Stark HI-I, Chat E, Zeme NP, Rickard TA, Ashworth CR. Fracture of the hook of the Hamate. J BorneJ o l t Su• 1989; 71A:1202--1207. 7. Stark HH, Jobe FW, Boyes JH, Ashworth CR. Fractm'e of the hook of the Hamate in athletes. J Bone Joint Surg 1977; 59A:S75-582.