- Email: [email protected]
Post-traumatic irreducible nondissociative carpal instability: A case report
Post-traumatic Irreducible Nondissociative Carpal Instability: A Case Report Donald M. Arms, MD, Robert A. Martin, MD, William B. Strecker, MD, Louis A. Gilula, MD, St. Louis, MO We present a case that is unusual in two respects. To our knowledge, it is the first clearly documented instance in the literature of a post-traumatic, irreducible nondissociative volar intercalated carpal instability to result from a known wrist flexion force and a known dorsal capsuloligamentous tear. Second, the same wrist revealed a coalition at both intraosseous levels of the proximal carpal row: a synfibrosis at the scapholunate joint and a synostosis at the lunotriquetral joint. Treatment by open removal of an interposed capsuloligamentous flap from the radiocarpal joint, followed by alignment of carpal elements, temporary internal fixation, and repair of the damaged dorsal capsule and ligaments gave an excellent result. (J Hand Surg 1995;20A:778-780.)
The diagnosis, treatment, and classification of carpal instability continues to evolve. Most classification systems identify the extent of injury in combination with roentgenographic and physical examination findings. In 1972, Linscheid et al. classified two types of carpal instability, dorsal and volar intercalated instability (DISI and VISI).' Cooney et al. more recently defined carpal instability as being either nondissociative (CIND) or dissociative (CID). 2 Nondissociative carpal instability presents with a carpal deformity (VISI or DISI) where the proximal carpal row acts as a unit. In CIND, there is no scapholunate or lunotriquetral dissociation, and therefore the entire proximal carpal row moves together. This pattern of VISI may be caused by
pathology at either the midcarpal or radiocarpal joints. 2 Most investigators report injury to the anterior radiocarpal ligaments as causing CIND deformities? However, more recent studies indicate that the dorsal ligaments also provide important control in carpal stability, such that disruption of the dorsal ligaments can cause both clinical and radiographic evidence of static anterior intercalated segment instability deformity. 4,5 These studies have been of dissociative instability (CID-VISI), but we report a case of post-traumatic irreducible nondissociative carpal instability of the CIND-VISI pattern, wherein similar dorsal ligament disruption seems to be a significant factor. Neither this cause nor the treatment, which we found to be effective, has been to our knowledge clearly outlined in the literature.
From the Department of Orthopedic Surgery and the Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO. Received for publication March 9, 1993; accepted in revised form Nov. 1, 1994. 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: Donald M. Arms, MD, Department of Orthopedic Surgery, Washington University School of Medicine, Suite 11300, West Pavilion, One Barnes Plaza, St. Louis, MO 63110.
Case Report
778
The Journal of Hand Surgery
A 17-year-old right-hand dominant man had fallen on his pronated palmarflexed left hand. Physical examination revealed diffuse swelling and tenderness over the midcarpal and radiocarpal joints dorsally and abrasions on the dorsum of the wrist. The patient's description of his injury and left upper extremity position during the fall were reliable. The
The Io)~r
posteroanterior x-ray film showed the entire proXimal carpal row to be foreshortened, with marked overlap of the distal carpal row by the proximal carpal row. The revised carpal height ratio (carpal height divided by capitate length) wag markedly abnormal. The scaphoid lay distally and dorsally with the lunate (Fig. 1A). Lateral x-ray films demonstrated abnormal capitolunate, radiocapitate, radioscaphoid, and radiotriquetral angles with a VISI deformity. The abnormality involved the radial, central, and ulnar columns (Fig. 1B). A wrist instability series showed bilateral lunotriquetral coalition, in addition to the previously described deformity. An attempt at closed reduction using 15 lbs of longitudinal traction and additional m~in~taltraction by the two operating surgeons was unsuc~e~s-fuL Surgical exploration via a dorsal approach r~vealed failure of segmentation Of both fne--l~n-otriquetral and scapholunate joints, with the tmtire proximal carpal row appearing as a single car~al bone. The scapholunate coalition appeared to be.a synfibrosis and formed a true bond between the scaphoid and lunate. The scapholunate joint was filled with fibrous tissue. There was a transverse rent in ~he dorsal capsule, which
of Hand Surgery / Vol. 20A No. 5 September 1995
779
formed a proximally based flap of the dorsal capsule in the radioscaphoid joint that prevented reduction. The dorsal radiocarpal ligament, a thickened region of the radiocarpal joint capsule, was injured and formed distally and proximally based flaps along with the injured capsule. The injury involved most of the capsule, sparing only the most radial portion. The palmar ligamentous structures appeared intact. The dorsal proximally based flap was removed from the joint, allowing the entire proximal row to rotate easily into a reduced position using mild manual longitudinal traction. There was no significant articular surface damage. The midcarpal and radiocarpal joints were then reduced, and a large Steinmann pin was passed from the third metacarpal, across the capitate and lunate, and into the distal radius. Prior to pin placement, the reduction was relatively stable. However, subluxation of the radiocarpal joint was visualized with axial loading and wrist flexion to about 60 ~. The dorsal capsule was imbricated by overlapping the two flaps. At a 7-month follow-up examination, the patient had slightly decreased grip strength but good painless function. X-ray films revealed no change in his anatomic bony alignment from that seen on films taken immediately before surgery.
Figure 1. X-ray films of patient on presentation. (A) Posteroanterior view. Marked foreshortening of the proximal row is evident. The scaphoid shows a prominent cortical ring sign and the triangular-shaped lunate is tilted. (B) Lateral view. Note the palmar tilting of the scaphoid, lunate, and triquetrum with abnormal capitolunate, radiocapitate, radioscaphoid, and radiotriquetral angles indicative of a VISI configuration.
780
Arms eta[. / Nondissociative Carpal Instability
Figure 2. Seven months after surgery. (A) Posteroanterior and (B) latt,,~ll,@-rayfilms demonstrate normal carpal and radiocarpal.alignment. The lunotriquetral coalitioa is unchanged compared Im (AJ wJaen the slight difference in wrist position is ~onsidered.
Discussion CIND has been described to explain pathologic rotation of the entire proximal carpal row in the absence of intercarpal ligament injury (eg, scapholunate or lunotriquetral ligament injuries). The injury presented in this Ease report fits the criteria of a CIND-VISI pattern. I-I~we~er, unlike almost all cases previously described, our pa~ent had dorsal, not palmar, pathology. Coalitions of both lunotriquetrar and scapho~nate joints were noted at surgery. Even upon a retrospective review of the x-ray films, the scapholunate coalition was not appreciated. These coalitions allowed the entire proximal row to rotate as a unit following injury to the dorsal radiocarpal ligament and associated capsule. The patient's mechanism of injury and previous biomechanicat studies might help explain this unique injury. Viegas et al.5 and Horii et al.4 have noted the importance of the dorsal ligaments in each kinematic study. We suspect that our patient sustained axial and palmar compression and a dorsal stretch (tension) injury as the wrist was forced into full flexion. The hand and both carpal rows were probably subluxed dorsally away from the forearm and could not spontaneously reduce as hand
trod forearm alignment was regained, because the proximally based dorsal capsuloligamentous flap became interposed between the carpus and forearm. This primary dorsal mechanism for nondissociative carpal instability may be more common than is known, but no other reports that we know of so clearly demonstrate mechanism, pathology, and treatment.
References 1. Linscheid RL, Dobyns JH, Beabout JW, Bryan RS. Traumatic instability of the wrist: diagnosis, classification, and pathomechanics. J Bone Joint Surg 1972;54A:1612-32. 2. Cooney WP, Linscheid RL, Dobyns JH. Carpal instability: treatment of ligament injuries of the wrist. AAOS Instructional Course Lectures. Chicago: American Academy of Orthopaedic Surgeons, 1992;41:33-44. 3. Alexander CE, Lichtman DM. Triquetrolunate and midcarpal instability. In: Lichtman DM, ed. The wrist and its disorders. Philadelphia: WB Saunders, 1988:274-85. 4. Horii E, Garcia-Elias M, et al. A kinematic study of lunotriquetral dissociations. J Hand Surg 1991;16A:355-62. 5. Viegas SF, Patterson RM, Peterson PD, et al. Ulnar-sided perilunate instability: an anatomic and biomechanic study. J Hand Surg 1990;15A:268-78.
The diagnosis, treatment, and classification of carpal instability continues to evolve. Most classification systems identify the extent of injury in combination with roentgenographic and physical examination findings. In 1972, Linscheid et al. classified two types of carpal instability, dorsal and volar intercalated instability (DISI and VISI).' Cooney et al. more recently defined carpal instability as being either nondissociative (CIND) or dissociative (CID). 2 Nondissociative carpal instability presents with a carpal deformity (VISI or DISI) where the proximal carpal row acts as a unit. In CIND, there is no scapholunate or lunotriquetral dissociation, and therefore the entire proximal carpal row moves together. This pattern of VISI may be caused by
pathology at either the midcarpal or radiocarpal joints. 2 Most investigators report injury to the anterior radiocarpal ligaments as causing CIND deformities? However, more recent studies indicate that the dorsal ligaments also provide important control in carpal stability, such that disruption of the dorsal ligaments can cause both clinical and radiographic evidence of static anterior intercalated segment instability deformity. 4,5 These studies have been of dissociative instability (CID-VISI), but we report a case of post-traumatic irreducible nondissociative carpal instability of the CIND-VISI pattern, wherein similar dorsal ligament disruption seems to be a significant factor. Neither this cause nor the treatment, which we found to be effective, has been to our knowledge clearly outlined in the literature.
From the Department of Orthopedic Surgery and the Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO. Received for publication March 9, 1993; accepted in revised form Nov. 1, 1994. 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: Donald M. Arms, MD, Department of Orthopedic Surgery, Washington University School of Medicine, Suite 11300, West Pavilion, One Barnes Plaza, St. Louis, MO 63110.
Case Report
778
The Journal of Hand Surgery
A 17-year-old right-hand dominant man had fallen on his pronated palmarflexed left hand. Physical examination revealed diffuse swelling and tenderness over the midcarpal and radiocarpal joints dorsally and abrasions on the dorsum of the wrist. The patient's description of his injury and left upper extremity position during the fall were reliable. The
The Io)~r
posteroanterior x-ray film showed the entire proXimal carpal row to be foreshortened, with marked overlap of the distal carpal row by the proximal carpal row. The revised carpal height ratio (carpal height divided by capitate length) wag markedly abnormal. The scaphoid lay distally and dorsally with the lunate (Fig. 1A). Lateral x-ray films demonstrated abnormal capitolunate, radiocapitate, radioscaphoid, and radiotriquetral angles with a VISI deformity. The abnormality involved the radial, central, and ulnar columns (Fig. 1B). A wrist instability series showed bilateral lunotriquetral coalition, in addition to the previously described deformity. An attempt at closed reduction using 15 lbs of longitudinal traction and additional m~in~taltraction by the two operating surgeons was unsuc~e~s-fuL Surgical exploration via a dorsal approach r~vealed failure of segmentation Of both fne--l~n-otriquetral and scapholunate joints, with the tmtire proximal carpal row appearing as a single car~al bone. The scapholunate coalition appeared to be.a synfibrosis and formed a true bond between the scaphoid and lunate. The scapholunate joint was filled with fibrous tissue. There was a transverse rent in ~he dorsal capsule, which
of Hand Surgery / Vol. 20A No. 5 September 1995
779
formed a proximally based flap of the dorsal capsule in the radioscaphoid joint that prevented reduction. The dorsal radiocarpal ligament, a thickened region of the radiocarpal joint capsule, was injured and formed distally and proximally based flaps along with the injured capsule. The injury involved most of the capsule, sparing only the most radial portion. The palmar ligamentous structures appeared intact. The dorsal proximally based flap was removed from the joint, allowing the entire proximal row to rotate easily into a reduced position using mild manual longitudinal traction. There was no significant articular surface damage. The midcarpal and radiocarpal joints were then reduced, and a large Steinmann pin was passed from the third metacarpal, across the capitate and lunate, and into the distal radius. Prior to pin placement, the reduction was relatively stable. However, subluxation of the radiocarpal joint was visualized with axial loading and wrist flexion to about 60 ~. The dorsal capsule was imbricated by overlapping the two flaps. At a 7-month follow-up examination, the patient had slightly decreased grip strength but good painless function. X-ray films revealed no change in his anatomic bony alignment from that seen on films taken immediately before surgery.
Figure 1. X-ray films of patient on presentation. (A) Posteroanterior view. Marked foreshortening of the proximal row is evident. The scaphoid shows a prominent cortical ring sign and the triangular-shaped lunate is tilted. (B) Lateral view. Note the palmar tilting of the scaphoid, lunate, and triquetrum with abnormal capitolunate, radiocapitate, radioscaphoid, and radiotriquetral angles indicative of a VISI configuration.
780
Arms eta[. / Nondissociative Carpal Instability
Figure 2. Seven months after surgery. (A) Posteroanterior and (B) latt,,~ll,@-rayfilms demonstrate normal carpal and radiocarpal.alignment. The lunotriquetral coalitioa is unchanged compared Im (AJ wJaen the slight difference in wrist position is ~onsidered.
Discussion CIND has been described to explain pathologic rotation of the entire proximal carpal row in the absence of intercarpal ligament injury (eg, scapholunate or lunotriquetral ligament injuries). The injury presented in this Ease report fits the criteria of a CIND-VISI pattern. I-I~we~er, unlike almost all cases previously described, our pa~ent had dorsal, not palmar, pathology. Coalitions of both lunotriquetrar and scapho~nate joints were noted at surgery. Even upon a retrospective review of the x-ray films, the scapholunate coalition was not appreciated. These coalitions allowed the entire proximal row to rotate as a unit following injury to the dorsal radiocarpal ligament and associated capsule. The patient's mechanism of injury and previous biomechanicat studies might help explain this unique injury. Viegas et al.5 and Horii et al.4 have noted the importance of the dorsal ligaments in each kinematic study. We suspect that our patient sustained axial and palmar compression and a dorsal stretch (tension) injury as the wrist was forced into full flexion. The hand and both carpal rows were probably subluxed dorsally away from the forearm and could not spontaneously reduce as hand
trod forearm alignment was regained, because the proximally based dorsal capsuloligamentous flap became interposed between the carpus and forearm. This primary dorsal mechanism for nondissociative carpal instability may be more common than is known, but no other reports that we know of so clearly demonstrate mechanism, pathology, and treatment.
References 1. Linscheid RL, Dobyns JH, Beabout JW, Bryan RS. Traumatic instability of the wrist: diagnosis, classification, and pathomechanics. J Bone Joint Surg 1972;54A:1612-32. 2. Cooney WP, Linscheid RL, Dobyns JH. Carpal instability: treatment of ligament injuries of the wrist. AAOS Instructional Course Lectures. Chicago: American Academy of Orthopaedic Surgeons, 1992;41:33-44. 3. Alexander CE, Lichtman DM. Triquetrolunate and midcarpal instability. In: Lichtman DM, ed. The wrist and its disorders. Philadelphia: WB Saunders, 1988:274-85. 4. Horii E, Garcia-Elias M, et al. A kinematic study of lunotriquetral dissociations. J Hand Surg 1991;16A:355-62. 5. Viegas SF, Patterson RM, Peterson PD, et al. Ulnar-sided perilunate instability: an anatomic and biomechanic study. J Hand Surg 1990;15A:268-78.