BEWARE THE SPRAINED WRIST

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1 BEWARE THE SPRAINED WRIST THE INCIDENCE AND DIAGNOSIS OF SCAPHOLUNATE INSTABILITY W. A. JONES From Broadgreen Hospital, Liverpool A consecutive series of 100 cases of wrist injury, other than those referred with a radial fracture, have been reviewed to determine the incidence of acute scapholunate instability; a clenched fist radiograph was used in addition to the routine scaphoid views. Of 19 patients with an increase in the scapholunate gap, five were eventually considered to have significant scapholunate instability, two in association with Colles fractures. Injuries producing significant ligamentous damage and carpal instability may be as common as scaphoid fractures. They require special consideration in diagnosis and management. Sprained wrist is a common diagnosis in accident departments, but which of the carpal ligaments are sprained and to what extent they have been disrupted is rarely considered. Since the classic article by Linscheid et a!. (197) much has been written on carpal instability, but the diagnosis is often made only after chronic patterns of instability have become established. Mayfie!d, Johnson and Kilcoyne (1980) have shown that a combination of dorsiflexion, ulnar deviation and intercarpa! supination of the wrist and carpus can result in a spectrum of bony and ligamentous injuries culminating in perilunate and lunate dislocations and their variants. The injury usually begins with damage to the scapholunate ligament complex ; this consists of the scapholunate interosseous membrane, the volar radioscapholunate ligament, and the superficial dorsal scapholunate ligament. Complete injuries to all of these components result in complete scapholunate dissociation, which is also described as rotatory subluxation of the scaphoid. Partial injuries to this ligament complex have been recognised as causing symptoms of instability (Linscheid et al. 1983; Beckenbaugh 1984). Mayfield (1984) described two patterns of partial failure and Sebald, Dobyns and Linscheid (1974) outlined how, with the passage of time and further ligament attenuation, these injuries may evolve into better recognised patterns of chronic instability. The radiographic changes seen with W. A. Jones, MCh(Orth), FRCS, FRCS Ed, Senior Orthopaedic Registrar Broadgreen Hospital, Thomas Drive, Liverpool L14 3LB, England. Requests for reprints should be sent to Mr W. A. Jones, 4 Field Lane, Fazakerley, Liverpool Ll0 OAG, England British Editorial Society of Bone and Joint Surgery 030l60X/88/059 $.00 J Bone Joint Surg [Br] 1988:70B:937. these partial lesions are often subtle and frequently missed. An attempt was therefore made to discover the true incidence of acute scapholunate instability among cases of wrist injury (excluding those with obvious fractures of the radius) referred from the Accident Department for wrist radiographs. PATIENTS AND METHOD From October 1986 all patients referred for radiographs of the wrist had an additional anteroposterior view performed with the fist clenched. This view was taken on the same cassette as the three standard views, so there was little additional cost. When the fist is clenched a compressive force across the midcarpa! joint is transmitted to the scapholunate junction by the head of the capitate. If there is any scapholunate instability, radiographic separation of the bones becomes apparent or is increased (Linscheid et a!. 197; Sebald et a!. 1974; Dobyns et al. 1975; Gilu!a and Weeks 1978). One hundred consecutive cases were reviewed and all abnormalities were documented. In all patients, the scapholunate interval was measured between the proxima! poles of the two bones on standard PA views (static gap) and on the AP clenchedfist views (enhanced gap). Those with a static or enhanced scapholunate separation ofmore than mm (Linscheid et al. 197) were reviewed clinically. Enquiry was made into the mechanism of injury, the initial treatment, and the persistence of symptoms. Any persistent tenderness and the range of wrist movements were recorded. At followup further PA, true lateral, and clenchedfist radiographs were taken of both wrists. From these the scapholunate interval and scapholunate angle on each side were compared, and the presence of a carpa! collapse or of the scaphoid cortical ring sign was noted. VOL. 70B, No., MARCH

2 94 w. A. JONES The radiographic features of established scapholunate dissociation are shown in Figure 1. On the PA view, there is widening of the scapholunate gap (normally mm or less) and a cortical ring sign is seen. This latter sign is produced by the flexed attitude adopted by the scaphoid ; its distal part is seen endon. The dissociated lunate, because of its wedged shape, is pushed into dorsiflexion by the capitate, producing flexion at the lunatecapitate joint. This collapse deformity of the carpus is best seen on the lateral view and is termed dorsiflexed intercalated segment instability (DISI). The dorsiflexion of the lunate and the palmarfiexion of the scaphoid give an increase in the scapholunate angle from the normal value of 40#{176} to 60#{176} (Linscheid et al. 197). Table I. Final diagnosis in 100 consecutive patients with wrist injuries, after excluding obvious fractures of the distal radius Diagnosis Fracture of scaphoid Waist Proximal pole Number Flake fracture of triquetrum 3 Fracture of distal radius I Fracture of distal radius plus scapholunate instability Scapholunate instability 3 Normal 76 Total RESULTS Ofthe 100 patients whose radiographs were reviewed, 19 were found to have a scapholunate gap in excess of mm on either the static or dynamic views and were therefore examined in more detail. A summary of the findings in all 100 wrists is given in Table I. In 14 of the 19 patients a similar radiographic appearance was present in both wrists ; these patients were not considered to have sustained significant injuries to the scapholunate ligament complex. All but one of the 14 patients were asymptomatic and normal on examination when reviewed an average of 10 weeks after injury. The symptomatic patient also had abnormal clinical signs ; he was a 0yearold who had fallen on a palmarflexed wrist and his radiographs showed a static 3 mm scapholunate gap on radiographs taken 10 days apart. Radiographs taken eight weeks after injury showed a proximal scaphoid fracture. The mean static scapholunate gap in these 14 patients was. mm in their injured wrist, and.0 mm in their uninjured wrist (range, mm to 3.5 mm on both sides). The mean enhanced scapholunate gap was 3 mm (range.5 mm to 3.5 mm) in both wrists. The mean scapho!unate angle was 57#{176} in the injured wrist and 55#{176} in the uninjured wrist. Only two of these patients had static scapholunate gaps greater than mm, one being the patient with a scaphoid fracture, the other showing gaps of 3.5 mm in both wrists, and scapholunate angles of 54#{176} and 55#{176}. In the remaining 1 patients a gap of greater than mm had appeared only in the clenchedfist views. These values appear to reflect normal variation in the scapholunate interval. The remaining five patients (those with significant unilateral changes) were all thought to have significant injury to the scapholunate ligament complex, with clinical and radiographic evidence of instability. Details ofthese five patients are given in Table II and illustrated in Figures to 6. At the scapholunate joint, the mean static gap at presentation was.9 mm rising to a mean enhanced gap of 3.5 mm. The mean scapholunate angle was 70#{176}. The corresponding mean values for the normal wrist were mm static, mm (enhanced) and 56#{176}. At the time of review, a mean of 1 weeks after Fig. Ia The radiographic signs of complete scapholunate dissociation. 1. Widening of the scapholunate gap.. Cortical ring sign. 3. Dorsiflexed intercalated segment instability of the carpus (see text). 4. Increase in the scapholunate angle. THE JOURNAL OF BONE AND JOINT SURGERY

3 BEWARE THE SPRAINED WRIST 95 injury (range 6 to 0 weeks) all five patients still had symptoms. In two of these patients a malunited Colles fracture probably caused most of the symptoms, but in both there was also radiographic evidence of scapholunate instability. In three of the five this was present on the initial film, but in the other two, scapholunate Separation was apparent only on the clenchedfist views. DISCUSSION Case 1. Clenchedfist views of both wrists showing an increase in the scapholunate gap on the left. Fig. 3 Fig. 4 Figure 3 Case. Static increase in the scapholunate gap seen six weeks after the initial injury Figure 4 Case 3. Static scapholunate gap seen six weeks after injury. There is a united fracture of the scaphoid tubercle. Fig. 5a Fig. Sb Case 4. The PA view (Fig. Sa) shows a static scapholunate gap in association with a Colles fracture. The lateral view (Fig. Sb) shows secondary carpal collapse following malunion. The increase in scapholunate angle to 84#{176} is only possible if there is also some scapholunate dissociation. Fig. 6a Fig. 6b Case 5. Radiographs of a displaced Colles fracture in plaster. An increased scapholunate gap is evident and on the lateral view secondary carpal collapse is seen. The increased scapholunate angle again suggests scapholunate dissociation. Ligament injuries range from minor sprains with no instability to complete rupture with gross instability. Between these two extremes there may be variable ligament disruption with different degrees of instability. Of 100 patients with wrist injuries, five were identified with injury to the scapholunate ligament complex sufficient to cause instability, though none appeared to have complete dissociation. This finding suggests that these injuries are more common than is usually recognised. In two cases, scapholunate instability was associated with a Co!!es fracture. Linscheid et a!. (197) have described a secondary collapse deformity of the carpus following ma!union of Colles fractures; this usually responds to osteotomy of the radius. Taleisnik (1980) classifies this deformity with dorsal carpal translocation amongst his proximal carpal instabilities and has also described midcarpal instability caused by malunion of distal radial fractures (Taleisnik and Watson 1984). These instability patterns are secondary to malunion of a fracture and not necessarily due to intercarpal injuries occurring at the time of the injury. Although the carpal collapse in these two cases (Fig. Sb and Fig. 6) would seem to be secondary to the malunion, the unilateral increase in scapholunate separation suggests the simultaneous occurrence of the Colles fracture and the scapholunate injury. Cooney, Dobyns and Linscheid (1980) also report this association: they reviewed 565 Colles fractures, and found five with associated intercarpal injuries, four of whom required reconstruction of the scapholunate ligament. This combination of injuries was also produced experimentally by Mayfield (1984). Obvious fractures of the distal radius were at first excluded from the series but of the 14 which slipped the net, two had associated scapholunate instability. This seems a high proportion, and one wonders about the true incidence ofthis association. This is likely to be higher in comminuted fractures, particularly those with loose, ligamentbearing volar fragments. In most instances the!igamentous injury presumably heals unrecognised whilst the fracture is uniting in plaster. Three patients showed partial injury of the scapholunate ligament complex. The subtlety of the radiographic changes and the difficulties of diagnosis have been emphasised by Sebald et a!. (1984). Scapholunate gaps of VOL. 70B, No., MARCH 1988

4 96 w. A. JONES Table II. Details of five patients with scapholunate instability : all patients fell on the outstretched left hand (changes in the scapholunate gap and angle are given) Affected wrist Normal wrist Gap (mm) Scapholunate Gap (mm) Scapholunate Time in angle angle Follow up plaster Case Age Sex Static Enhanced (degrees) Static Enhanced (degrees) (weeks) (weeks) I 53 F Remained painful with restricted Fig movement and slight DISI. 8 M 4 Slight discomfort but improving. Fig tender with restricted movement Aftera 6week interval 3 3 M Plaster applied for fracture of Fig scaphoid tubercle; diastasis increased in plaster 4 69 F 3.5 Fig Associated Colles fracture: 4 malunion with carpal collapse F Associated Colles fracture: Fig Loss of position in plaster; malunion with carpal collapse DISI, dorsiflexed intercalated segment instability 4 mm or more and scapholunate angles of over 85#{176} are easy to diagnose ; but when the scapholunate gap is under 4 mm and the angle is from 60#{176} to 80#{176} there may be no clear distinction between normality and abnormality. Angulatory changes may be present without a gap and vice versa. These difficulties have been clearly shown. The difference in mean values between the 14 patients without significant injury and the five who had instability is not very striking; the importance of comparing appearances with the normal wrist is evident. The importance of this injury may be doubted; clinics are not full of patients with chronic wrist sprains, but many patients do remain symptomatic for prolonged periods after injury, others return with established chronic instability and some may find that minor symptoms are tolerable but may later develop degenerative changes. Increased awareness of these injuries will clarify the natural history. 1 t seems that significant and potentially serious ligamentous disruption may be as common as fracture of the scaphoid, but frequently goes undiagnosed and untreated, being passed off as a simple sprain. It is no longer adequate only to exclude a scaphoid fracture; simple sprains do occur but significant injury will be diagnosed only with a high index of suspicion and improved historytaking and examination (Beckenbaugh 1984). A dynamic clenchedfist view should routinely be included in a scaphoid series. Patients with a history of a fall on the thenar eminence, pain in the anatomical snuffbox or at the scapholunate interval, and with static or enhanced scapholunate gaps of over mm should have radiographs of the contralateral wrist taken, and the scapholunate angles should be measured. An angle of 65#{176} or greater strengthens the diagnosis of scapholunate instability, paricularly if the unaffected wrist is within normal range. Instability which is seen on dynamic views only may be treated in a scaphoid type cast for 6 to 8 weeks, though radiographs should be taken through the cast at intervals to ensure continued reduction. Static scapholunate separation is more difficult to treat. Palmer, Dobyns and Linscheid (1978) suggest that a closed reduction may be achieved and the position held in plaster for 6 to 8 weeks. Persistence of diastasis in a cast is an indication for arthrography to confirm the diagnosis before treatment by either open reduction or percutaneous pinning (Green and O Brien 1980). I would like to acknowledge the invaluable assistance of Dr J. H. E. Carmichael, Senior Consultant Radiologist at Broadgreen Hospital, who assisted with the radiological review. REFERENCES Beckenbaugh RD. Accurate evaluation and management of the painful wrist following injury : an approach to carpal instability. Orthop Clin North Am 1984:15: Cooney WP III, Dobyns JH, Linscheid RL. Complications of Colles fractures. J Bone Joint Surg [Am] 1980:6A :6139. Dobyns JH, Linacheid RL, Chao EYS, Weber ER, Swanson GE. Traumatic instability of the wrist. AAOS Instructional Course Lectures. St Louis: CV Mosby, 1975:4:1899. Gilula LA, Weeks PM. Posttraumatic ligamentous instabilities of the wrist. Radiology 1978:19: THE JOURNAL OF BONE AND JOINT SURGERY

5 BRIEF REPORTS 97 Green DP, O Brien El. Classification and management of carpal dislocations. Clin Orthop 1980:149:557. Linscheid RL, Dobyns JH, Beabout JW, Bryan RS. Traumatic instability of the wrist : diagnosis, classification and pathomechanics. J Bone Joint Surg [Am] 197,54A:16l3. Linscheid RL, Dobyns JH, Beckenbaugh RD, Cooney WP III, Wood MB. Instability patterns of the wrist. J Hand Surg 1983:8(5 Pt )686. Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations : pathomechanics and progressive perilunar instability. J Hand Surg 1980:5:641. Mayfield JK. Wrist ligamentous anatomy and pathogenesis of carpal instability. Orthop Clin North Am 1984:15:0916. Palmer AK, Dobyns JH, Linscheid RL. Management of posttraumatic instability of the wrist secondary to ligament rupture. J Hand Surg 1978 ;3 :5073. Sebald JR, Dobyns JH, Linscheid RL. The natural history of collapse deformities of the wrist. C/in Orthop 1974:104:1408. laleisnik J. Posttraumatic carpal instability. C/in Ort hop 1980; 149:738. laleisnik J, Watson HK. Midcarpal instability caused by malunited fractures of the distal radius. J Hand Surg (Am) 1984:9:3507. PROMINENT RADIAL TUBERCLE CAUSING LIMITED PRONATION: BRIEF REPORT C. OLERUD, B. SAHLSTEDT, S. OLERUD We describe a patient whose symptoms mimicked those of tennis elbow (radial epicondylitis). She remained undiagnosed and unsuccessfully treated for many years, but once the correct diagnosis of enlargement of the radial tuberosity was established a simple operation relieved her symptoms. Case report. In 1973 a 4yearold woman sought help for a slowly progressing ache in her right elbow. There was no history of trauma. The pain was aggravated by exercise but absent at rest. There was slight tenderness over the lateral epicondyle but movements were full. Pain could be provoked by forced pronation and palmarflexion of the wrist. She was thought to have a tennis elbow (radial epicondylitis) and was treated with analgesics and periods of rest which proved adequate for a time. Fig. I Fig. 4 C. Oierud, MD, Dr Med Sc, Department of Orthopaedics B. Sahlstedt, MD, Associate Professor, Department of Radiology S. Olerud, Professor and Head, Department of Orthopaedics University Hospital, , Uppsala, Sweden. Correspondence to Dr C. Olerud British Editorial Society of Bone and Joint Surgery X/88/R44 $.00 J Bone Joint Surg [Br] 1988 :70B :978. Over the years, however, her symptoms grew worse and pronation became increasingly restricted so that, by 198, it was only 5#{176}. She was a postoffice clerk but it was almost impossible for her to write or even to use an ordinary calculator. Her pronation was not improved by local anaesthetic injection. Her radiographs had been considered normal, but new films taken a year later VOL.70B, No., MARCH 1988