- Email: [email protected]
Type IV flexor digitorum profundus avulsion
Vol. lSA, No. 5 September 1990
Dorsal wrist synovectomies in rheumatoid hands
patients have increasing intraatticular destruction and slightly more than one half of the patients with increasing intraarticular destruction require revision surgery.
REFERENCES
6.
7.
1. Aschan W, Moberg E. A long-term study of the effect
of early synovectomy in rheumatoid arthritis. Bull Hosp Jt Dis (Ortho Institute) 1984;44: 106-21. 2. Mongan ES, Boger WM, Gilliland BC, Meyerowitz S. Synovectomy in rheumatoid arthritis. Arth Rheum 1970; 13:761-8. 3. Abernathy PJ, Dennyson WG. Decompression of the extensor tendons at the wrist in rheumatoid arthritis.
8.
9. 10.
J Bone Joint Surg 1979;61B:64-8.
4. Clayton ML. Surgical treatment
at the wrist in rheumatoid arthritis. J Bone Joint Surg 1965;47A:741-50. 5. Edstrom B, Lugnegard H, Syk B. Late synovectomy of
11.
the hand in rheumatoid arthritis. Stand J Rheumatol 1976;5:184-90. Kessler I, Vainio K. Posterior (dorsal) synovectomy for rheumatoid involvement of the hand and wrist. J Bone Joint Surg 1966;48A: 1085-94. Lipscomb P. Synovectomy of the wrist for rheumatoid arthritis. JAMA 1965;194:655-9. Millender L, Nalebuff EA, Albin R, Ream RJ, Gordon M. Dorsal tenosynovectomy and tendon transfer in the rheumatoid hand. J Bone Joint Surg 1974;56A:601-10. Straub L, Ranawat C. The wrist in rheumatoid arthritis. J Bone Joint Surg 1969;51A:l-20. Thirupathi RG, Ferlic DC, Clayton ML. Dorsal wrist synovectomy in rheumatoid arthritis-a long-term study. J Hand Surg 1983;8:848-56. Brumfield RH Jr. Ranch0 Los Amigos Functional Test. Contemp Orthop 1984;8:67-71.
Type IV flexor digitorum profundus avulsion Flexor diitorum
profundus avulsions, are well-documented
a distal phalanx fragment.
injuries OccasionaIIy associated with
While the injury may involve primarily
either tendon or bone, a
rarely observed variant combines both tendon aud bone avuisions. A type IV variant seen after two sequential iqjuries is described. (J HAND SURC 1990;15A:735-9.)
W. Andrew Eglseder, Bethesda, h4d.
A v&ions
LCDR, MC, USNR, and John M. Russell, CDR, MC, USN,
of the flexor digitorum
pro-
From the Hand Surgery Service, Department of Orthopaedics, Naval Hospital, Bethesda, Md. The assertions or opinions contained herein are the private ones of the authors and are not to be construed as official or as reflecting the views of the Uniformed Services University of the Health Sciences (USUHS), Department of the Navy or the Department of Defense. Received for publication Feb. 16, 1989; accepted in revised form Oct. 12, 1989. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: W. Andrew Eglseder, LCDR, MC, USNR, Director, Hand Surgery Service, Department of Orthopaedics, Naval Hospital, Bethesda, MD 20814-5011. 3/l/17894
fundus (FDP) have become well-known injuries. I-5 Emphasis in diagnosis and timely repair is the key to successful management. The injury patterns most readily recognized are those classified by Leddy and Packer,6* ’ based primarily on the level of retraction of the injured tendon. Type I avulsions involve retraction of the FDP to the palm level. Type II retract to the level of the proximal interphalangeal (PIP) joint or super& cialis decussation and may contain a small fragment of bone, and type III are retained at the A4 pulley usually carrying a large fragment of distal phalanx. An extension of this classification system has been suggested by Smith.’ These designated type IV avulsions consist of a bone fragment avulsion from the distal phalanx and an associated tendon avulsion from the fragment with subsequent retraction of the tendon. The following case represents a variant of the type IV avulsions.
THE JOURNALOF HANDSURGERY735
736
The Journal of HAND SURGERY
Eglseder and Russell
Fig. 1. Lateral radiograph of right ring finger shows a displaced intraarticular distal phalanx fracture and dorsal subluxation
of the distal phalanx.
Case report A 3 l-year-old, right-handed white man had sequential hyperextension injuries to his right ring finger at the distal interphalangeal joint (DIP). The injury occurred October 3, 1987 by an unknown mechanism while playing football. Evaluation by the senior author was delayed until October 6, 1987. His initial complaints included swelling of the ring finger, pain with finger motion, and inability to flex the DIP. Additional questioning revealed an injury to the same ring finger in May 1987 while water skiing. The recalled mechanism involved hooking the ring finger on the tow rope. Subsequent to his May 1987 injury, he noted an inability to flex the DIP joint for approximately 2 weeks, followed by restoration of about 25% to 50% of DIP motion. He also noticed a subjective reduction in grip strength for an extended period. Pertinent positive physical examination findings included an inability to flex the DIP, distal digital swelling, and tenderness. There were no palmar findings and the digit was neurovascularly intact. Radiographs showed an avulsion fracture at the palmar base of the distal phalanx comprising approximately 30% of the articular surface. The fragment was rotated 90 degrees and there was an associated dorsal subluxation of the distal phalanx (Fig. 1). A presumptive diagnosis of a Leddy type III injury was made before operation. A palmar Bruner approach was performed October 14, 1987. Initial exploration showed the avulsed fragment, rotated 90 degrees. It was reduced, stabilized with a 2.0 cortical screw to allow compression and avoid transarticular Kirschner (K)wire fixation, and a rotation-controlling 24-gauge pull-out wire. The palmar plate remained attached to the fragment; however, the quantity of FDP fibers attached to the fragment
appeared grossly inadequate. Inspection of the cascade demonstrated persistent extension at the DIP. Proximal exploration showed partial scarring of the avulsed FDP fibers to the palmar plate. The bulk of the avulsed FDP was located at the level of the A2 pulley. The tendon was hemorrhagic with a few central fibers sharply frayed, presumed ruptured in the recent injury, with peripheral fibers rolled smooth, suggesting chronic changes (Fig. 2). A pseudotendon was not encountered. The FDP was advanced through the pulley system and attached to the distal phalanx with a 4.0 pull-out wire with cascade restoration (Fig. 3). His postoperative management consisted of a dorsal block splint with dynamic traction allowing active and passive extension of the DIP. Night extension splinting commenced 2 weeks after operation. On December 4, 1987 the screw and interosseous wire were removed and a portion of the tendon was inserted into the screw hole. The patient resumed occupational therapy with active range of motion only. Scheduling difficulties precluded removal of the pull-out wire until January 4, 1988. The final clinical evaluation on July 12, 1988 showed resumption of full daily and athletic activities without restrictions. The patient did note mild discomfort at the PIP joint while gripping a tennis racket, despite a sensation of improved grip strength with a racketball racket. His range of motion was metacarpophalangeal85/0, PIP 98/ + 10, DIP 62/5, for a PIP/DIP TAM of 165 degrees (Fig. 4, A and B). (The patient had mild hyperextension of the PIP on initial presentation.) JAMAR grip dynamometer testing showed essentially symmetric grip strength. He displayed a normal nail and had a very slightly positive Tinel’s sign at the distal palmar aspect of the incision over the distal phalanx.
Vol. 15A, No, 5
September 1990
Type IV flexor digitorum
profundus
avulsiorl
737
Fii. 2. Avulsed flexor digitorum protimdus of ring finger retrieved through a transverse window between A2 and Cl pulley. (Straight arrow), acute changes. (Curved arrow), chronic changes.
Fig. 3. Lateral radiograph of distal phalanx after open reduction out wire and hook for dynamic traction.
Discussion F’DP injuries are not uncommon, with early diagnosis, classification, and treatment critical to clinical success. The type I, II, III classification system advanced by Leddy and Packer remains unchallenged; however, it has been supplemented with the Smith type IV variant. Among the spectrum of FDP avulsions, the ring finger is involved in approximately 75% of the cases. 3Our case is representative of the involvement of
and internal fixation; with pull-
the ring finger. Accepted predispositions include reduced breaking strength of the ring finger FDP insertion, and the prominence of ring finger -during grasp initiation. More controversial issues hinge on the pathodynamic mechanism of the avulsion. The lack of independent motion of the ring finger is a consistently implicated theme in the injury. GunteP states that the common profundus muscle belly of the long, ring, and small fingers account for the less independent motion
738
The Journal of HAND SURGERY
Eglseder and Russell
Fig. 4. A-B, Final active range of motion of right ring finger. A, Flexion. B, Extension. demonstrating mild hyperextension interphalangeal joint.
of proximal interphalangeal
of the ring finger increasing susceptibility to the injury. Leddy and Packeti. ’ attribute the predisposition to reduced ring finger MP extension imposed by the extensor juncturae check-reins of the small and fingers. The independent action of the index finger and a rapid drop out of the small finger during grasp subjects the long and ring fingers to the final resistive action of a pullaway flexion as cited by Manske and Lasker.” Lunn and Lamb” concluded that the ring finger bipennate lumbrical muscle tethers the FDP leading to rupture. Finally, Bynum and Gilbert” have recently reported that the ring finger tip is most prominent during grasp ini-
joint and flexion contracture
of distal
tiation and is exposed to the greatest force during pullaway testing. The unique feature of this case is the suggested time sequence in the “double avulsion.” Profundus injuries, including simultaneous bone and tendon avulsions, have been previously recognized. Bohler noted in Carroll’s* article a 50% association of tendon avulsion with bone fragments. This was not specifically addressed by Carroll. Robins and Dobyns13cited two cases of the double rupture phenomenon; however, Smith’s report of this entity is credited with the addition of the type IV avulsion injury to the Leddy and Packer clas-
Vol. 15A, No. 5 September 1990
sification. Lange and Posner have subsequently reported another case.14All reported cases presume a double rupture with a single acute injury. This case fulfills criteria for a type IV injury pattern, with the history suggesting a previously unreported delayed double avulsion. The patient appears to have sustained a partial avulsion of the FDP or an FDP avulsion with tethering by tbe vinculae brevis, as implied by his reported return of DIP motion a couple of weeks after his initial injury. The absence of a pseudotendon mitigates against complete rupture with continuity restored by scarring. Inspection of the avulsed tendon at operation showed one central area with acute injury features including sharp fraying and central hemorrhage. The peripheral fibers demonstrated findings consistent with chronic changes, i.e., smooth, rounded fibers without associated hemorrhage .
Potential mechanisms for the apparent delayed “double avulsion” include a partial FDP avulsion at the initial injury with completion of the avulsion and fracture of the distal phalanx through the insertion of the palmar plate during hyperextension. Another consideration is tethering of the FDP by the vinculae brevis, allowing some DIP motion with completion of the avulsion and subsequent fracture by the retention effect of the palmar plate during hyperextension. REFERENCES 1. Blazina ME, Lane C. Rupture of the insertion of the flexor digitorum profundus tendon in student athletes. J Am Co11 Health Ass 1966;14:248-9.
Type IVJle.xor
digitorum
profundus
awlsion
739
2. Carroll RE, Match RM. Avulsion of the flexor profundus
tendon insertion. J Trauma 1970;10:1109-18. 3. Chang WH, Thorns OJ, White WL. Avulsion injury of the long flexor tendons. Plast Reconstr Surg 197250: 260-4. 4. Wenger DR. Avulsion of the profundus tendon insertion in football players. Arch Surg 1973;106:145-9. 5. Reef TC . Avulsion of the flexor digitorum profundus: an athletic injury. Am J Sports Med 1977;5:281-5. 6. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J HAND SURG 1977;2:66-9. 7. Leddy JP. Avulsion of the flexor digitorum profundus. Hand Clinics 1985;1:77-83. 8. Smith JH. Avulsion of a profundus tendon with simultaneous intraarticular fracture of the distal phalanx-case report. J HAND SURC 198 1;6:600-1. 9. Gunter GS. Traumatic avulsion of the insertion of flexor digitorum profundus. Aust N Z J Surg 1960;30:1-8. 10. Manske PR, Lesker PA. Avulsion of the ring finger flexor digitorum profundus: an experimental study. The Hand 1978;10:52-5. 11. Lunn PG, Lamb DW. “Rugby finger”-avulsion of profundus of ring finger. J HAND SURG 1984;9B:69-71. 12. Bynum DK, Gilbert JA. Avulsion of the flexor digitorum profundus: anatomic and biomechanical considerations. J HAND SURG 1984;13A:222-7. 13. Robins PR, Dobyns JH. Avulsion of the insertion of the flexor digitorum profundus tendon associated with fracture of the distal phalanx. A.A.O.S. Symposium on tendon surgery. March 1974:151-6. 14. Langa V, Posner MA. Unusual rupture of a flexor profundus tendon. J HAND SURG 1986;l lA:227-9.
Dorsal wrist synovectomies in rheumatoid hands
patients have increasing intraatticular destruction and slightly more than one half of the patients with increasing intraarticular destruction require revision surgery.
REFERENCES
6.
7.
1. Aschan W, Moberg E. A long-term study of the effect
of early synovectomy in rheumatoid arthritis. Bull Hosp Jt Dis (Ortho Institute) 1984;44: 106-21. 2. Mongan ES, Boger WM, Gilliland BC, Meyerowitz S. Synovectomy in rheumatoid arthritis. Arth Rheum 1970; 13:761-8. 3. Abernathy PJ, Dennyson WG. Decompression of the extensor tendons at the wrist in rheumatoid arthritis.
8.
9. 10.
J Bone Joint Surg 1979;61B:64-8.
4. Clayton ML. Surgical treatment
at the wrist in rheumatoid arthritis. J Bone Joint Surg 1965;47A:741-50. 5. Edstrom B, Lugnegard H, Syk B. Late synovectomy of
11.
the hand in rheumatoid arthritis. Stand J Rheumatol 1976;5:184-90. Kessler I, Vainio K. Posterior (dorsal) synovectomy for rheumatoid involvement of the hand and wrist. J Bone Joint Surg 1966;48A: 1085-94. Lipscomb P. Synovectomy of the wrist for rheumatoid arthritis. JAMA 1965;194:655-9. Millender L, Nalebuff EA, Albin R, Ream RJ, Gordon M. Dorsal tenosynovectomy and tendon transfer in the rheumatoid hand. J Bone Joint Surg 1974;56A:601-10. Straub L, Ranawat C. The wrist in rheumatoid arthritis. J Bone Joint Surg 1969;51A:l-20. Thirupathi RG, Ferlic DC, Clayton ML. Dorsal wrist synovectomy in rheumatoid arthritis-a long-term study. J Hand Surg 1983;8:848-56. Brumfield RH Jr. Ranch0 Los Amigos Functional Test. Contemp Orthop 1984;8:67-71.
Type IV flexor digitorum profundus avulsion Flexor diitorum
profundus avulsions, are well-documented
a distal phalanx fragment.
injuries OccasionaIIy associated with
While the injury may involve primarily
either tendon or bone, a
rarely observed variant combines both tendon aud bone avuisions. A type IV variant seen after two sequential iqjuries is described. (J HAND SURC 1990;15A:735-9.)
W. Andrew Eglseder, Bethesda, h4d.
A v&ions
LCDR, MC, USNR, and John M. Russell, CDR, MC, USN,
of the flexor digitorum
pro-
From the Hand Surgery Service, Department of Orthopaedics, Naval Hospital, Bethesda, Md. The assertions or opinions contained herein are the private ones of the authors and are not to be construed as official or as reflecting the views of the Uniformed Services University of the Health Sciences (USUHS), Department of the Navy or the Department of Defense. Received for publication Feb. 16, 1989; accepted in revised form Oct. 12, 1989. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: W. Andrew Eglseder, LCDR, MC, USNR, Director, Hand Surgery Service, Department of Orthopaedics, Naval Hospital, Bethesda, MD 20814-5011. 3/l/17894
fundus (FDP) have become well-known injuries. I-5 Emphasis in diagnosis and timely repair is the key to successful management. The injury patterns most readily recognized are those classified by Leddy and Packer,6* ’ based primarily on the level of retraction of the injured tendon. Type I avulsions involve retraction of the FDP to the palm level. Type II retract to the level of the proximal interphalangeal (PIP) joint or super& cialis decussation and may contain a small fragment of bone, and type III are retained at the A4 pulley usually carrying a large fragment of distal phalanx. An extension of this classification system has been suggested by Smith.’ These designated type IV avulsions consist of a bone fragment avulsion from the distal phalanx and an associated tendon avulsion from the fragment with subsequent retraction of the tendon. The following case represents a variant of the type IV avulsions.
THE JOURNALOF HANDSURGERY735
736
The Journal of HAND SURGERY
Eglseder and Russell
Fig. 1. Lateral radiograph of right ring finger shows a displaced intraarticular distal phalanx fracture and dorsal subluxation
of the distal phalanx.
Case report A 3 l-year-old, right-handed white man had sequential hyperextension injuries to his right ring finger at the distal interphalangeal joint (DIP). The injury occurred October 3, 1987 by an unknown mechanism while playing football. Evaluation by the senior author was delayed until October 6, 1987. His initial complaints included swelling of the ring finger, pain with finger motion, and inability to flex the DIP. Additional questioning revealed an injury to the same ring finger in May 1987 while water skiing. The recalled mechanism involved hooking the ring finger on the tow rope. Subsequent to his May 1987 injury, he noted an inability to flex the DIP joint for approximately 2 weeks, followed by restoration of about 25% to 50% of DIP motion. He also noticed a subjective reduction in grip strength for an extended period. Pertinent positive physical examination findings included an inability to flex the DIP, distal digital swelling, and tenderness. There were no palmar findings and the digit was neurovascularly intact. Radiographs showed an avulsion fracture at the palmar base of the distal phalanx comprising approximately 30% of the articular surface. The fragment was rotated 90 degrees and there was an associated dorsal subluxation of the distal phalanx (Fig. 1). A presumptive diagnosis of a Leddy type III injury was made before operation. A palmar Bruner approach was performed October 14, 1987. Initial exploration showed the avulsed fragment, rotated 90 degrees. It was reduced, stabilized with a 2.0 cortical screw to allow compression and avoid transarticular Kirschner (K)wire fixation, and a rotation-controlling 24-gauge pull-out wire. The palmar plate remained attached to the fragment; however, the quantity of FDP fibers attached to the fragment
appeared grossly inadequate. Inspection of the cascade demonstrated persistent extension at the DIP. Proximal exploration showed partial scarring of the avulsed FDP fibers to the palmar plate. The bulk of the avulsed FDP was located at the level of the A2 pulley. The tendon was hemorrhagic with a few central fibers sharply frayed, presumed ruptured in the recent injury, with peripheral fibers rolled smooth, suggesting chronic changes (Fig. 2). A pseudotendon was not encountered. The FDP was advanced through the pulley system and attached to the distal phalanx with a 4.0 pull-out wire with cascade restoration (Fig. 3). His postoperative management consisted of a dorsal block splint with dynamic traction allowing active and passive extension of the DIP. Night extension splinting commenced 2 weeks after operation. On December 4, 1987 the screw and interosseous wire were removed and a portion of the tendon was inserted into the screw hole. The patient resumed occupational therapy with active range of motion only. Scheduling difficulties precluded removal of the pull-out wire until January 4, 1988. The final clinical evaluation on July 12, 1988 showed resumption of full daily and athletic activities without restrictions. The patient did note mild discomfort at the PIP joint while gripping a tennis racket, despite a sensation of improved grip strength with a racketball racket. His range of motion was metacarpophalangeal85/0, PIP 98/ + 10, DIP 62/5, for a PIP/DIP TAM of 165 degrees (Fig. 4, A and B). (The patient had mild hyperextension of the PIP on initial presentation.) JAMAR grip dynamometer testing showed essentially symmetric grip strength. He displayed a normal nail and had a very slightly positive Tinel’s sign at the distal palmar aspect of the incision over the distal phalanx.
Vol. 15A, No, 5
September 1990
Type IV flexor digitorum
profundus
avulsiorl
737
Fii. 2. Avulsed flexor digitorum protimdus of ring finger retrieved through a transverse window between A2 and Cl pulley. (Straight arrow), acute changes. (Curved arrow), chronic changes.
Fig. 3. Lateral radiograph of distal phalanx after open reduction out wire and hook for dynamic traction.
Discussion F’DP injuries are not uncommon, with early diagnosis, classification, and treatment critical to clinical success. The type I, II, III classification system advanced by Leddy and Packer remains unchallenged; however, it has been supplemented with the Smith type IV variant. Among the spectrum of FDP avulsions, the ring finger is involved in approximately 75% of the cases. 3Our case is representative of the involvement of
and internal fixation; with pull-
the ring finger. Accepted predispositions include reduced breaking strength of the ring finger FDP insertion, and the prominence of ring finger -during grasp initiation. More controversial issues hinge on the pathodynamic mechanism of the avulsion. The lack of independent motion of the ring finger is a consistently implicated theme in the injury. GunteP states that the common profundus muscle belly of the long, ring, and small fingers account for the less independent motion
738
The Journal of HAND SURGERY
Eglseder and Russell
Fig. 4. A-B, Final active range of motion of right ring finger. A, Flexion. B, Extension. demonstrating mild hyperextension interphalangeal joint.
of proximal interphalangeal
of the ring finger increasing susceptibility to the injury. Leddy and Packeti. ’ attribute the predisposition to reduced ring finger MP extension imposed by the extensor juncturae check-reins of the small and fingers. The independent action of the index finger and a rapid drop out of the small finger during grasp subjects the long and ring fingers to the final resistive action of a pullaway flexion as cited by Manske and Lasker.” Lunn and Lamb” concluded that the ring finger bipennate lumbrical muscle tethers the FDP leading to rupture. Finally, Bynum and Gilbert” have recently reported that the ring finger tip is most prominent during grasp ini-
joint and flexion contracture
of distal
tiation and is exposed to the greatest force during pullaway testing. The unique feature of this case is the suggested time sequence in the “double avulsion.” Profundus injuries, including simultaneous bone and tendon avulsions, have been previously recognized. Bohler noted in Carroll’s* article a 50% association of tendon avulsion with bone fragments. This was not specifically addressed by Carroll. Robins and Dobyns13cited two cases of the double rupture phenomenon; however, Smith’s report of this entity is credited with the addition of the type IV avulsion injury to the Leddy and Packer clas-
Vol. 15A, No. 5 September 1990
sification. Lange and Posner have subsequently reported another case.14All reported cases presume a double rupture with a single acute injury. This case fulfills criteria for a type IV injury pattern, with the history suggesting a previously unreported delayed double avulsion. The patient appears to have sustained a partial avulsion of the FDP or an FDP avulsion with tethering by tbe vinculae brevis, as implied by his reported return of DIP motion a couple of weeks after his initial injury. The absence of a pseudotendon mitigates against complete rupture with continuity restored by scarring. Inspection of the avulsed tendon at operation showed one central area with acute injury features including sharp fraying and central hemorrhage. The peripheral fibers demonstrated findings consistent with chronic changes, i.e., smooth, rounded fibers without associated hemorrhage .
Potential mechanisms for the apparent delayed “double avulsion” include a partial FDP avulsion at the initial injury with completion of the avulsion and fracture of the distal phalanx through the insertion of the palmar plate during hyperextension. Another consideration is tethering of the FDP by the vinculae brevis, allowing some DIP motion with completion of the avulsion and subsequent fracture by the retention effect of the palmar plate during hyperextension. REFERENCES 1. Blazina ME, Lane C. Rupture of the insertion of the flexor digitorum profundus tendon in student athletes. J Am Co11 Health Ass 1966;14:248-9.
Type IVJle.xor
digitorum
profundus
awlsion
739
2. Carroll RE, Match RM. Avulsion of the flexor profundus
tendon insertion. J Trauma 1970;10:1109-18. 3. Chang WH, Thorns OJ, White WL. Avulsion injury of the long flexor tendons. Plast Reconstr Surg 197250: 260-4. 4. Wenger DR. Avulsion of the profundus tendon insertion in football players. Arch Surg 1973;106:145-9. 5. Reef TC . Avulsion of the flexor digitorum profundus: an athletic injury. Am J Sports Med 1977;5:281-5. 6. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J HAND SURG 1977;2:66-9. 7. Leddy JP. Avulsion of the flexor digitorum profundus. Hand Clinics 1985;1:77-83. 8. Smith JH. Avulsion of a profundus tendon with simultaneous intraarticular fracture of the distal phalanx-case report. J HAND SURC 198 1;6:600-1. 9. Gunter GS. Traumatic avulsion of the insertion of flexor digitorum profundus. Aust N Z J Surg 1960;30:1-8. 10. Manske PR, Lesker PA. Avulsion of the ring finger flexor digitorum profundus: an experimental study. The Hand 1978;10:52-5. 11. Lunn PG, Lamb DW. “Rugby finger”-avulsion of profundus of ring finger. J HAND SURG 1984;9B:69-71. 12. Bynum DK, Gilbert JA. Avulsion of the flexor digitorum profundus: anatomic and biomechanical considerations. J HAND SURG 1984;13A:222-7. 13. Robins PR, Dobyns JH. Avulsion of the insertion of the flexor digitorum profundus tendon associated with fracture of the distal phalanx. A.A.O.S. Symposium on tendon surgery. March 1974:151-6. 14. Langa V, Posner MA. Unusual rupture of a flexor profundus tendon. J HAND SURG 1986;l lA:227-9.