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Locking of the forearm in pronation due to extensor carpi ulnaris tendon dislocation with dorsal distal ulna dislocation
Locking of the Forearm in Pronation Due to Extensor Carpi Ulnaris Tendon Dislocation With Dorsal Distal Ulna Dislocation Satoshi Araki, MD, Satoru Kachi, MD, Shinji Mishima, MD, Toyota City, Japan
Dislocation of the extensor carpi ulnaris (ECU) tendon is known to cause pain or snapping of the ulnar side of the wrist and dorsal instability of the distal ulna. We report here a case of locking of the forearm in the pronated position caused by a dorsal dislocation of the distal ulna and palmar displacement of the ECU tendon. Case Report
dislocated anterior to the ulna and the ECU tendon sheath had disappeared. When supination was attempted, the ECU tendon pushed the ulnar head dorsally, locking the forearm in pronation (Fig. 2). After the ECU tendon was reduced to the dorsal side of the ulna, the forearm unlocked from the pronated position and the displaced ulnar head was also reduced in the normal position by the palmar direction force of the ECU tendon, As the ECU tendon was
A 13-year-old girl occasionally felt pain on the ulnar side of her right wrist before her right forearm abruptly locked in the pronated position while playing basketball. She had no pain or swelling after the injury; and after a month of therapy, she was seen at our hospital. On physical examination, the right forearm was locked in 70” pronation. When supination was attempted, the patient felt pain and the forearm remained fixed in pronation. X-ray films showed an ulna plus configuration and a dorsal dislocation of the distal ulna (Fig. 1). Our preoperative diagnosis was that dislocation of the distal ulna caused the locking, and we planned to reduce the distal radioulnar joint dislocation and shorten the ulna. At surgery, the ECU tendon was From the Department of Orthopaedic Surgery, Kamo Hospital, Toyota City, Japan. Received for publication Nov. 27, 1992; accepted in revised form Oct. 16, 1993. 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: Satoshi Araki. MD, Department of Otthopaedic Surgery, Kamo Hospital, 3-17 Motoshiro-cho, Toyota City, 471. Japan. 402
The Journal
of Hand
Surgery
Figure 1. (A) Posteroanterior and lateral x-ray the right wrist showing an ulnar plus variance. continues)
films of (Figure
.The Journal of Hand Surgery / Vol.
19A No. 3 May
1994
403
Figure 3. X-ray films 18 months after surgery showing the distal ulna reduced.
Discussion In 1970, Spinner and Kaplan’ described the ECU tendon as having an important role in stabilizing the distal radioulnar joint. This tendon works as the most important force against the dorsal dislocation force of the distal ulna.‘-’ In this case. the ECU Figure 1. (continued)
(B) Dorsal dislocation
of the distal
ulna.
unstable, it was fixed in the normal position by wrapping it with the extensor retinaculum, which was partially turned over and flapped. After surgery, the forearm was placed in a plaster bandage in supination for 6 weeks. Active exercises were then begun, and 3 months later, the patient resumed normal activities. Two years after the injury, forearm motion was almost normal and painless. Eighteen months later, x-ray films showed the ulnar head to be reduced (Fig. 3).
Figure 2. Palmar dislocation tendon.
of the extensor car-pi ulnaris
F
ECU subsheath
dw
ECU
Figure 4. The mechanism of occurrence of locking in the pronated position. (A) Normal relationship of the radius, ulna, and extensor carpi ulnaris (ECU) tendon. (B) Subluxation of the ECU tendon and dorsal subluxation of the ulnar head. (C) Palmar dislocation of the ECU tendon and dorsal dislocation of the ulnar head.
404
Araki
et al. I Dislocation
of the ECU Tendon
tendon lost its stabilizing effect by dislocating palmar to the distal ulna, locking the forearm in pronation (Fig. 4).
References 1. Spinner M, Kaplan E. Extensor carpi ulnaris: its relationship to the stability of the distal radioulnar joint. Clin Orthop 1970;68: 124-9. dislocation of 2. Eckhardt WA, Palmer AK. Recurrent
extensor carpi ulnaris tendon. J Hand Surg 1981:6: 629-3 1. 3. Burkhart SS, Wood MB, Linscheid RL. Posttraumatic recurrent subluxation of the extensor carpi ulnaris tendon. J Hand Surg 1982;7:1-3. 4. Vulpius J. Habitual dislocation of the extensor carpi ulnaris tendon. Acta Orthop Stand 1964;34: 105-8. 5. Cargouri BGR, Moula T. Luxation habituelle posttraumatique du tendon cutibal posterieur. Rev Chir Orthop 1989;75:345-6.
Dislocation of the extensor carpi ulnaris (ECU) tendon is known to cause pain or snapping of the ulnar side of the wrist and dorsal instability of the distal ulna. We report here a case of locking of the forearm in the pronated position caused by a dorsal dislocation of the distal ulna and palmar displacement of the ECU tendon. Case Report
dislocated anterior to the ulna and the ECU tendon sheath had disappeared. When supination was attempted, the ECU tendon pushed the ulnar head dorsally, locking the forearm in pronation (Fig. 2). After the ECU tendon was reduced to the dorsal side of the ulna, the forearm unlocked from the pronated position and the displaced ulnar head was also reduced in the normal position by the palmar direction force of the ECU tendon, As the ECU tendon was
A 13-year-old girl occasionally felt pain on the ulnar side of her right wrist before her right forearm abruptly locked in the pronated position while playing basketball. She had no pain or swelling after the injury; and after a month of therapy, she was seen at our hospital. On physical examination, the right forearm was locked in 70” pronation. When supination was attempted, the patient felt pain and the forearm remained fixed in pronation. X-ray films showed an ulna plus configuration and a dorsal dislocation of the distal ulna (Fig. 1). Our preoperative diagnosis was that dislocation of the distal ulna caused the locking, and we planned to reduce the distal radioulnar joint dislocation and shorten the ulna. At surgery, the ECU tendon was From the Department of Orthopaedic Surgery, Kamo Hospital, Toyota City, Japan. Received for publication Nov. 27, 1992; accepted in revised form Oct. 16, 1993. 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: Satoshi Araki. MD, Department of Otthopaedic Surgery, Kamo Hospital, 3-17 Motoshiro-cho, Toyota City, 471. Japan. 402
The Journal
of Hand
Surgery
Figure 1. (A) Posteroanterior and lateral x-ray the right wrist showing an ulnar plus variance. continues)
films of (Figure
.The Journal of Hand Surgery / Vol.
19A No. 3 May
1994
403
Figure 3. X-ray films 18 months after surgery showing the distal ulna reduced.
Discussion In 1970, Spinner and Kaplan’ described the ECU tendon as having an important role in stabilizing the distal radioulnar joint. This tendon works as the most important force against the dorsal dislocation force of the distal ulna.‘-’ In this case. the ECU Figure 1. (continued)
(B) Dorsal dislocation
of the distal
ulna.
unstable, it was fixed in the normal position by wrapping it with the extensor retinaculum, which was partially turned over and flapped. After surgery, the forearm was placed in a plaster bandage in supination for 6 weeks. Active exercises were then begun, and 3 months later, the patient resumed normal activities. Two years after the injury, forearm motion was almost normal and painless. Eighteen months later, x-ray films showed the ulnar head to be reduced (Fig. 3).
Figure 2. Palmar dislocation tendon.
of the extensor car-pi ulnaris
F
ECU subsheath
dw
ECU
Figure 4. The mechanism of occurrence of locking in the pronated position. (A) Normal relationship of the radius, ulna, and extensor carpi ulnaris (ECU) tendon. (B) Subluxation of the ECU tendon and dorsal subluxation of the ulnar head. (C) Palmar dislocation of the ECU tendon and dorsal dislocation of the ulnar head.
404
Araki
et al. I Dislocation
of the ECU Tendon
tendon lost its stabilizing effect by dislocating palmar to the distal ulna, locking the forearm in pronation (Fig. 4).
References 1. Spinner M, Kaplan E. Extensor carpi ulnaris: its relationship to the stability of the distal radioulnar joint. Clin Orthop 1970;68: 124-9. dislocation of 2. Eckhardt WA, Palmer AK. Recurrent
extensor carpi ulnaris tendon. J Hand Surg 1981:6: 629-3 1. 3. Burkhart SS, Wood MB, Linscheid RL. Posttraumatic recurrent subluxation of the extensor carpi ulnaris tendon. J Hand Surg 1982;7:1-3. 4. Vulpius J. Habitual dislocation of the extensor carpi ulnaris tendon. Acta Orthop Stand 1964;34: 105-8. 5. Cargouri BGR, Moula T. Luxation habituelle posttraumatique du tendon cutibal posterieur. Rev Chir Orthop 1989;75:345-6.