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Absent Ring Finger Flexor Digitorum Profundus Presenting as a Jersey Finger
CASE REPORT
Absent Ring Finger Flexor Digitorum Profundus Presenting as a Jersey Finger: Case Report and Review of the Literature Brad Hyatt, MD,* Peter C. Rhee, DO, MS,* Steven L. Moran, MD,† Scott P. Steinmann, MD† We report the case of a patient who presented with an apparent acute avulsion of the ring finger flexor digitorum profundus (FDP), or jersey finger. At surgery, the FDP to the ring finger was found to be absent; also absent were the lumbrical to the ring finger and the A5 pulley. Absence of the FDP was confirmed with postoperative imaging. Although absent profundus tendons have been previously reported, none have involved the FDP to the ring finger. However, various reports have described abnormal connections between the ring and little finger flexor tendons. (J Hand Surg Am. 2016;-(-):-e-. Copyright Ó 2016 by the American Society for Surgery of the Hand. All rights reserved.) Key words Absent ring finger flexor digitorum profundus, Jersey finger, FDP.
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profundus (FDP) tendons to the digits has been reported in only 5 cases1e4; however, none of these has involved the ring finger. Avulsion injuries to the FDP tendon, called “Jersey finger,” are common among athletes, with the ring finger accounting for 75% of cases.5 We present a case of a suspected acute FDP avulsion injury to the ring finger with congenital absence of the FDP confirmed intraoperatively and with advanced imaging of the upper extremity. HE ABSENCE OF FLEXOR DIGITORUM
CASE REPORT A 19-year-old right handedominant man presented with right ring finger pain after an injury while participating in collegiate football practice. The index, middle, ring, and little fingers were caught in an opponent’s helmet and were forced into hyperextension. He denied From the *Department of Orthopaedic Surgery and Rehabilitation, San Antonio Military Medical Center, Fort Sam Houston, TX; and the †Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN. Received for publication March 12, 2015; accepted in revised form February 3, 2016. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Scott P. Steinmann, MD, Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; e-mail: [email protected]. 0363-5023/16/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2016.02.003
previous trauma to the right hand. The pain was most severe at the ring finger proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints. At rest, the ring finger was found to have soft tissue edema and slight flexion at the PIP and MCP joints; no flexion was noted at the DIP joint. The lengths of the phalanges were proportional to the hand and symmetric to the contralateral side. There were normal skin creases at the MCP, PIP, and distal interphalangeal (DIP) joints. He was tender to palpation along the volar aspects of the PIP and MCP joints. There was no tenderness at the volar base of the distal phalanx or within the palm along the course of the flexor tendons to the ring finger, although there was pain with passive range of motion of the DIP joint, as well as the PIP and MCP joints. Isolated testing of the FDS tendon to the ring finger indicated that it was intact. However, testing of the FDP revealed an inability to flex the DIP of the ring finger digit in isolation. The FDP and FDS tendons to the remaining digits were all intact. Plain radiographs showed no fracture (Fig. 1). The presumptive diagnoses were FDP tendon avulsion and PIP joint volar plate injury. Surgery was offered for repair of a presumed FDP tendon avulsion. The patient underwent surgery 7 days after the injury. The ring finger was approached with a Bruner incision centered on the DIP and the base of the distal phalanx was exposed. The FDP tendon was absent at
Ó 2016 ASSH
r
Published by Elsevier, Inc. All rights reserved.
r
1
2
ABSENT RING FINGER FDP: JERSEY FINGER
FIGURE 2: Ring finger PIP joint flexion with traction on FDS; note the absence of FDP.
FIGURE 1: A Anteroposterior and B lateral views of the involved ring finger. Note soft tissue swelling about the proximal phalanx and absence of avulsion.
the DIP joint level. There was no evidence of fracture and no hematoma with an intact volar plate. Furthermore, the A5 pulley was not present. A second incision was made at the level of the A1 pulley and extending proximally, which revealed no FDP tendon, hematoma, or tenosynovitis (Fig. 2). Proximal excursion of the FDS into this incision showed absence of the normal decussation; Camper chiasm was not evaluated. A third incision was made in the volar distal forearm, where FDP tendons to the middle and small fingers were identified; however, the FDP tendon to the ring finger was absent. The palmar and forearm incisions were incorporated into an extensile exposure of zones 3 and 4 of the flexor tendons. An abnormal tendinous connection was found between the little finger profundus tendon proximally (zone 4) and the ring finger superficialis tendon just proximal to the A1 pulley, without a muscle belly for the FDP of the ring finger (Fig. 3). In addition, no lumbrical muscles to the ring finger or ring finger contribution to the little finger lumbrical were identified. After surgery, advanced imaging with ultrasound and MRI confirmed intraoperative findings of the absence of the FDP musculotendinous unit to the ring finger (Fig. 4). The patient did have an intact FDP tendon to the ring finger on the uninjured extremity by physical examination. He also could not recall any deficiencies in his ability to flex the ring finger normally before the J Hand Surg Am.
FIGURE 3: Abnormal tendinous connection between the little finger FDP tendon proximally (white arrow) to the ring finger FDS tendon distally (black arrow) with absence of the ring finger FDP and lumbricals.
injury. Six weeks after surgery, he returned to play collegiate football with no reports of notable dysfunction in the right hand. DISCUSSION Whereas the FDS to the little finger is absent in up to 6% to 16% of patients,6 an absent FDP is much less common, with 5 cases reported in the literature: 1 index1 and 2 little2,3 fingers with complete FDP absence, and 2 instances of an absent FDP muscle belly.4 Miura et al3 described a 54-year-old woman who sustained a right little finger FDS avulsion in the setting of congenital absence of the FDP to the little finger. Complete absence of the little finger FDP and avulsion of the FDS with retraction to the level of the PIP joint were confirmed by both preoperative MRI and inspection during surgery. Furrer et al2 reported on a 9-year-old boy with an absent FDP to the little finger associated with hypoplasia of the metacarpal and phalanges resulting in 5 mm of shortening compared with the contralateral little finger. FDP absence was confirmed with MRI. r
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ABSENT RING FINGER FDP: JERSEY FINGER
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FIGURE 4: Postsurgical MRI image at the level of A metacarpal heads and B carpus show an absence of the FDP tendon within the ring finger. The FDS and FDP to all remaining digits are identifiable.
Kay and Lees1 described a child with absence of the FDS and FDP tendons to the index finger. At surgery, the authors found an adequate FDP muscle belly with a proximal tendon anlage. The FDP tendon ended with diffuse soft tissue attachments, and they identified “a thin, atrophic band of fibrous tissue occupying the fibrous flexor canal distal to [the] superficialis insertion.” Our patient’s perceived acute loss of active DIP flexion and the presence of a DIP flexion crease may be explained by an anomalous diminutive tendinous or membranous extension to the ring finger distal phalanx that could have ruptured before or during the current injury. Although a remote rupture of a normal FDP tendon is a possible explanation, a congenital abnormality is more likely, given no history of tendon injury, the lack of tendon remnants and fibrosis, and the absence of the A5 pulley and lumbrical muscles. Hypoplastic profundus and superficialis tendons to the little finger have been reported in 2 patients.4 In both patients, the FDS and FDP tendons to the little finger had normal insertions but proximally transitioned to membranous tissue and were not in continuity with any muscle fibers. Two instances of abnormal FDP tendons are also noteworthy.7,8 Masaki et al7 reported on a 26-year-old man who injured the little finger when he firmly gripped an opponent’s clothing during a rugby game. In this case the distal tendon stump extended to zone 3. The proximal FDP tendon to the little finger was not found despite intraoperative exploration within the forearm. Magnetic resonance imaging of the contralateral hand identified an FDP tendon to the little finger that branched from the FDP to the ring at the midpalmar level, which suggesting that on the injured side, the rupture occurred at the point where the shared tendon branched into little finger and ring finger contributions. Finally, Scalan et al8 described a 47-year-old man who sustained complete laceration of the little finger
J Hand Surg Am.
profundus in the forearm but retained partial active flexion at the DIP joint. The authors performed dissections on 2 cadavers and found that one of the specimens exhibited tendinous connections between the ring and little finger profundus tendons at the level of the lumbrical. Our patient, however, was found to have an anomalous tendinous connection between the little finger profundus and the ring finger superficialis tendons without lumbricals to the ring finger. Abnormalities of the ring finger profundus tendon are rare; abnormal connections to the little finger profundus tendon are more common than complete absence of the musculotendinous unit. This case illustrates a patient with unilateral absence of the ring finger FDP musculotendinous structure, which can pose a diagnostic challenge when the history and examination suggest an acute avulsion of the ring finger FDP tendon. REFERENCES 1. Kay SPJ, Lees VC. Anomalies of digital flexor tendons. In: Gupta A, Kay SPJ, Sheker LR, eds. The Growing Hand. 1st ed. London, UK: Mosby; 2000:326e329. 2. Furrer M, Schweizer A, Meuli-Simmen C. Aplasia of the flexor digitorum profundus tendon of the small finger. J Hand Surg Eur Vol. 2007;32(1):111e112. 3. Miura T, Tokuyama N, Ohya J. Spontaneous rupture of the flexor digitorum superficialis tendon of the little finger with aplasia of the flexor digitorum profundus tendon. J Hand Surg Eur Vol. 2010;35(3): 237e238. 4. Fukuoka M, Takayama S, Seki A. Congenital defects of the flexor digitorum profundus tendon of the little finger. Hand Surg. 2014;19(2): 253e256. 5. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J Hand Surg Am. 1977;2(1):66e69. 6. Tan JS, Oh L, Louis DS. Variation of the flexor digitorum superficialis as determined by an expanded clinical examination. J Hand Surg Am. 2009;34(5):900e906. 7. Masaki F, Isao T, Aya Y, Ryuuji I, Yohjiroh M. Spontaneous flexor tendon rupture of the flexor digitorum profundus secondary to an anatomic variant. J Hand Surg Am. 2007;32(8):1196e1199. 8. Scanlan MW, Ehrlich RV, Straugh RJ. Partially retained small finger flexor digitorum profundus function despite complete tendon loss in the forearm. J Hand Surg Am. 2004;29(4):591e594.
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Vol. -, - 2016
Absent Ring Finger Flexor Digitorum Profundus Presenting as a Jersey Finger: Case Report and Review of the Literature Brad Hyatt, MD,* Peter C. Rhee, DO, MS,* Steven L. Moran, MD,† Scott P. Steinmann, MD† We report the case of a patient who presented with an apparent acute avulsion of the ring finger flexor digitorum profundus (FDP), or jersey finger. At surgery, the FDP to the ring finger was found to be absent; also absent were the lumbrical to the ring finger and the A5 pulley. Absence of the FDP was confirmed with postoperative imaging. Although absent profundus tendons have been previously reported, none have involved the FDP to the ring finger. However, various reports have described abnormal connections between the ring and little finger flexor tendons. (J Hand Surg Am. 2016;-(-):-e-. Copyright Ó 2016 by the American Society for Surgery of the Hand. All rights reserved.) Key words Absent ring finger flexor digitorum profundus, Jersey finger, FDP.
T
profundus (FDP) tendons to the digits has been reported in only 5 cases1e4; however, none of these has involved the ring finger. Avulsion injuries to the FDP tendon, called “Jersey finger,” are common among athletes, with the ring finger accounting for 75% of cases.5 We present a case of a suspected acute FDP avulsion injury to the ring finger with congenital absence of the FDP confirmed intraoperatively and with advanced imaging of the upper extremity. HE ABSENCE OF FLEXOR DIGITORUM
CASE REPORT A 19-year-old right handedominant man presented with right ring finger pain after an injury while participating in collegiate football practice. The index, middle, ring, and little fingers were caught in an opponent’s helmet and were forced into hyperextension. He denied From the *Department of Orthopaedic Surgery and Rehabilitation, San Antonio Military Medical Center, Fort Sam Houston, TX; and the †Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN. Received for publication March 12, 2015; accepted in revised form February 3, 2016. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Scott P. Steinmann, MD, Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; e-mail: [email protected]. 0363-5023/16/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2016.02.003
previous trauma to the right hand. The pain was most severe at the ring finger proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints. At rest, the ring finger was found to have soft tissue edema and slight flexion at the PIP and MCP joints; no flexion was noted at the DIP joint. The lengths of the phalanges were proportional to the hand and symmetric to the contralateral side. There were normal skin creases at the MCP, PIP, and distal interphalangeal (DIP) joints. He was tender to palpation along the volar aspects of the PIP and MCP joints. There was no tenderness at the volar base of the distal phalanx or within the palm along the course of the flexor tendons to the ring finger, although there was pain with passive range of motion of the DIP joint, as well as the PIP and MCP joints. Isolated testing of the FDS tendon to the ring finger indicated that it was intact. However, testing of the FDP revealed an inability to flex the DIP of the ring finger digit in isolation. The FDP and FDS tendons to the remaining digits were all intact. Plain radiographs showed no fracture (Fig. 1). The presumptive diagnoses were FDP tendon avulsion and PIP joint volar plate injury. Surgery was offered for repair of a presumed FDP tendon avulsion. The patient underwent surgery 7 days after the injury. The ring finger was approached with a Bruner incision centered on the DIP and the base of the distal phalanx was exposed. The FDP tendon was absent at
Ó 2016 ASSH
r
Published by Elsevier, Inc. All rights reserved.
r
1
2
ABSENT RING FINGER FDP: JERSEY FINGER
FIGURE 2: Ring finger PIP joint flexion with traction on FDS; note the absence of FDP.
FIGURE 1: A Anteroposterior and B lateral views of the involved ring finger. Note soft tissue swelling about the proximal phalanx and absence of avulsion.
the DIP joint level. There was no evidence of fracture and no hematoma with an intact volar plate. Furthermore, the A5 pulley was not present. A second incision was made at the level of the A1 pulley and extending proximally, which revealed no FDP tendon, hematoma, or tenosynovitis (Fig. 2). Proximal excursion of the FDS into this incision showed absence of the normal decussation; Camper chiasm was not evaluated. A third incision was made in the volar distal forearm, where FDP tendons to the middle and small fingers were identified; however, the FDP tendon to the ring finger was absent. The palmar and forearm incisions were incorporated into an extensile exposure of zones 3 and 4 of the flexor tendons. An abnormal tendinous connection was found between the little finger profundus tendon proximally (zone 4) and the ring finger superficialis tendon just proximal to the A1 pulley, without a muscle belly for the FDP of the ring finger (Fig. 3). In addition, no lumbrical muscles to the ring finger or ring finger contribution to the little finger lumbrical were identified. After surgery, advanced imaging with ultrasound and MRI confirmed intraoperative findings of the absence of the FDP musculotendinous unit to the ring finger (Fig. 4). The patient did have an intact FDP tendon to the ring finger on the uninjured extremity by physical examination. He also could not recall any deficiencies in his ability to flex the ring finger normally before the J Hand Surg Am.
FIGURE 3: Abnormal tendinous connection between the little finger FDP tendon proximally (white arrow) to the ring finger FDS tendon distally (black arrow) with absence of the ring finger FDP and lumbricals.
injury. Six weeks after surgery, he returned to play collegiate football with no reports of notable dysfunction in the right hand. DISCUSSION Whereas the FDS to the little finger is absent in up to 6% to 16% of patients,6 an absent FDP is much less common, with 5 cases reported in the literature: 1 index1 and 2 little2,3 fingers with complete FDP absence, and 2 instances of an absent FDP muscle belly.4 Miura et al3 described a 54-year-old woman who sustained a right little finger FDS avulsion in the setting of congenital absence of the FDP to the little finger. Complete absence of the little finger FDP and avulsion of the FDS with retraction to the level of the PIP joint were confirmed by both preoperative MRI and inspection during surgery. Furrer et al2 reported on a 9-year-old boy with an absent FDP to the little finger associated with hypoplasia of the metacarpal and phalanges resulting in 5 mm of shortening compared with the contralateral little finger. FDP absence was confirmed with MRI. r
Vol. -, - 2016
ABSENT RING FINGER FDP: JERSEY FINGER
3
FIGURE 4: Postsurgical MRI image at the level of A metacarpal heads and B carpus show an absence of the FDP tendon within the ring finger. The FDS and FDP to all remaining digits are identifiable.
Kay and Lees1 described a child with absence of the FDS and FDP tendons to the index finger. At surgery, the authors found an adequate FDP muscle belly with a proximal tendon anlage. The FDP tendon ended with diffuse soft tissue attachments, and they identified “a thin, atrophic band of fibrous tissue occupying the fibrous flexor canal distal to [the] superficialis insertion.” Our patient’s perceived acute loss of active DIP flexion and the presence of a DIP flexion crease may be explained by an anomalous diminutive tendinous or membranous extension to the ring finger distal phalanx that could have ruptured before or during the current injury. Although a remote rupture of a normal FDP tendon is a possible explanation, a congenital abnormality is more likely, given no history of tendon injury, the lack of tendon remnants and fibrosis, and the absence of the A5 pulley and lumbrical muscles. Hypoplastic profundus and superficialis tendons to the little finger have been reported in 2 patients.4 In both patients, the FDS and FDP tendons to the little finger had normal insertions but proximally transitioned to membranous tissue and were not in continuity with any muscle fibers. Two instances of abnormal FDP tendons are also noteworthy.7,8 Masaki et al7 reported on a 26-year-old man who injured the little finger when he firmly gripped an opponent’s clothing during a rugby game. In this case the distal tendon stump extended to zone 3. The proximal FDP tendon to the little finger was not found despite intraoperative exploration within the forearm. Magnetic resonance imaging of the contralateral hand identified an FDP tendon to the little finger that branched from the FDP to the ring at the midpalmar level, which suggesting that on the injured side, the rupture occurred at the point where the shared tendon branched into little finger and ring finger contributions. Finally, Scalan et al8 described a 47-year-old man who sustained complete laceration of the little finger
J Hand Surg Am.
profundus in the forearm but retained partial active flexion at the DIP joint. The authors performed dissections on 2 cadavers and found that one of the specimens exhibited tendinous connections between the ring and little finger profundus tendons at the level of the lumbrical. Our patient, however, was found to have an anomalous tendinous connection between the little finger profundus and the ring finger superficialis tendons without lumbricals to the ring finger. Abnormalities of the ring finger profundus tendon are rare; abnormal connections to the little finger profundus tendon are more common than complete absence of the musculotendinous unit. This case illustrates a patient with unilateral absence of the ring finger FDP musculotendinous structure, which can pose a diagnostic challenge when the history and examination suggest an acute avulsion of the ring finger FDP tendon. REFERENCES 1. Kay SPJ, Lees VC. Anomalies of digital flexor tendons. In: Gupta A, Kay SPJ, Sheker LR, eds. The Growing Hand. 1st ed. London, UK: Mosby; 2000:326e329. 2. Furrer M, Schweizer A, Meuli-Simmen C. Aplasia of the flexor digitorum profundus tendon of the small finger. J Hand Surg Eur Vol. 2007;32(1):111e112. 3. Miura T, Tokuyama N, Ohya J. Spontaneous rupture of the flexor digitorum superficialis tendon of the little finger with aplasia of the flexor digitorum profundus tendon. J Hand Surg Eur Vol. 2010;35(3): 237e238. 4. Fukuoka M, Takayama S, Seki A. Congenital defects of the flexor digitorum profundus tendon of the little finger. Hand Surg. 2014;19(2): 253e256. 5. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J Hand Surg Am. 1977;2(1):66e69. 6. Tan JS, Oh L, Louis DS. Variation of the flexor digitorum superficialis as determined by an expanded clinical examination. J Hand Surg Am. 2009;34(5):900e906. 7. Masaki F, Isao T, Aya Y, Ryuuji I, Yohjiroh M. Spontaneous flexor tendon rupture of the flexor digitorum profundus secondary to an anatomic variant. J Hand Surg Am. 2007;32(8):1196e1199. 8. Scanlan MW, Ehrlich RV, Straugh RJ. Partially retained small finger flexor digitorum profundus function despite complete tendon loss in the forearm. J Hand Surg Am. 2004;29(4):591e594.
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Vol. -, - 2016