We have reviewed 20 patients with stage-iiib and

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1 Radial osteotomy for late-stage Kienböck s disease WEDGE OSTEOTOMY VERSUS RADIAL SHORTENING N. Iwasaki, A. Minami, N. Oizumi, N. Suenaga, H. Kato, M. Minami From Hokkaido University School of Medicine and Hokkaido Orthopaedic Memorial Hospital, Sapporo, Japan We have reviewed 20 patients with stage-iiib and stage-iv Kienböck s disease in order to examine the efficacy of two forms of radial osteotomy, namely radial wedge osteotomy and radial shortening. Lateral closing wedge osteotomies and radial shortenings were carried out on 11 and nine patients, respectively. There were no preoperative differences with respect to age, gender, and radiological stage. After a mean follow-up of 29 months, all patients, in both groups, had either a good or an excellent outcome. After the lateral closing wedge osteotomy, the radioscaphoid angle significantly increased and the Ståhl index significantly decreased. Progression of the degenerative changes at the radioscaphoid joint was found in two patients in this group. By contrast, there were no significant changes in any radiological parameters after radial shortening. Both procedures gave acceptable clinical results in stage-iiib and stage-iv Kienböck s disease. J Bone Joint Surg [Br] 2002;84-B: Received 5 July 2001; Accepted after revision 12 October 2001 The aetiology of Kienböck s disease, or lunate malacia, remains unclear. Treatment includes conservative measures and surgical procedures such as excision arthroplasty, 1-3 radial osteotomy (shortening and wedge resection), 4-10 limited intercarpal fusions, and vascularised bone grafting. 15 Hulten 16 recognised that there was a positive correlation between Kienböck s disease and negative ulnar variance. N. Iwasaki, MD, Assistant Professor A. Minami, MD, Professor N. Oizumi, MD, Hand Fellow N. Suenaga, MD, Assistant Professor H. Kato, MD, Assistant Professor Department of Orthopaedic Surgery, Hokkaido University School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo , Japan. M. Minami, MD, Consultant Orthopaedic Surgeon Hokkaido Orthopaedic Memorial Hospital, Hiragishi-7-13, Toyohira-ku, Sapporo , Japan. Correspondence should be sent to Dr N. Iwasaki British Editorial Society of Bone and Joint Surgery X/02/ $2.00 Joint-levelling procedures, either by lengthening the ulna or shortening the radius, are based on this concept. A number of biomechanical and clinical studies have supported jointlevelling procedures as being an effective extra-articular method of unloading the lunate. 4,6-8,10,17-22 Tsumura et al, 23,24 however, described a radial wedge osteotomy which decreased radial inclination, also referred to as a lateral closing osteotomy, as another extra-articular procedure for the treatment of Kienböck s disease, with either negative or positive ulnar variance. Using a two-dimensional rigidbody spring model, they showed that this osteotomy reduced the compressive force on the affected lunate. A satisfactory outcome has been reported after this procedure. 5,9 Although favourable clinical results have been reported after radial osteotomies, they cannot restore an already collapsed lunate and malrotation of the scaphoid. Therefore the effect of radial osteotomy remains questionable in the treatment of patients with advanced stages of Kienböck s disease. Our aim therefore was to determine whether radial osteotomies, including radial wedge osteotomy and radial shortening, affect Kienböck s disease of stage IIIB and stage IV of Alexander and Lichtman 25 (Table I), and whether there are differences between the postoperative results of these procedures. Patients and Methods Between 1983 and 1999 we treated 20 patients by either radial wedge osteotomy or radial shortening for Kienböck s disease of stage IIIB and stage IV (Table II). Lateral closing wedge osteotomies of the radius were carried out on 11 patients with ulna-zero or ulna-plus variance (CW group), and radial shortenings were performed on nine patients with ulnar-minus variance (RS group). The right hand was dominant in all patients. There were no significant differences between the groups in terms of age, stage of disease and duration of follow-up. The patients were evaluated clinically and radiologically. Clinical evaluation was based on a modification of the scoring system of Nakamura et al 5 (Table III) in which radiological assessment was excluded. Revascularisation or healing of the diseased lunate and the progression of degenerative changes were determined on standard antero- VOL. 84-B, NO. 5, JULY

2 674 N. IWASAKI, A. MINAMI, N. OIZUMI, N. SUENAGA, H. KATO, M. MINAMI Table I. The radiological classification of Kienböck s disease according to Alexander and Lichtman 25 Stage Radiological findings I Normal except for the possibility of either a linear or a compression fracture II Definite changes in density apparent in the lunate relative to the other carpal bones IIIA Collapse of the entire lunate without fixed rotation of the scaphoid IIIB Collapse of the entire lunate with fixed rotation of the scaphoid IV As for stage III with generalised degenerative changes in the carpus Table II. Details of the 11 patients treated by a lateral closing wedge (CW) osteotomy and the nine treated by radial shortening (RS) CW RS Mean (range) age in years 35.8 (13 to 60) 31.9 (17 to 59) Gender M 8 4 F 3 5 Site Right 9 3 Left 2 6 Lichtman stage 25 IIIB 10 8 IV 1 1 Mean (range) follow-up in months 27 (12 to 66) 31 (12 to 108) Table III. Scoring system for the assessment of clinical results after radial osteotomy according to Nakamura et al 5 Points Pain in the wrist None 10 Mild with strenuous activity 7 Mild with light work 4 Grip strength (% of unaffected side) Increase in range of extension/flexion arc (degrees) > to to 9 3 Overall grade (maximum points 21) Excellent 15 to 21 Good 9 to 14 Fair/poor <8 posterior (AP) and lateral radiographs of the wrist. Any progression of degenerative change was detected by the appearance of a bony spur, joint narrowing or of subchondral bone sclerosis. Healing of the lunate depended on improvement in the sclerotic or cystic changes. Radiological parameters including the radioscaphoid angle, carpal height ratio and Ståhl s index, were also measured. The radioscaphoid angle is the angle between a line drawn along the palmar aspect of the scaphoid from its proximal pole to the tuberosity and the axis of the radius on the lateral radiograph. The carpal height ratio is defined on the AP radiograph as the carpal height divided by the length of the third metacarpal. 2 Ståhl s index uses lateral radiographs to quantify collapse of the lunate. The height of the lunate (proximal-distal dimension) is divided by its diameter (AP dimension). 26 The lateral closing wedge osteotomy reduced the radial inclination of 15 by resecting a radially based wedge and closing the gap. Radial shortening was achieved by making two parallel transverse cuts to remove a segment of bone, the length of which equalled the amount of negative ulnar variance measured on the preoperative radiograph. In both procedures, fixation was provided by a five- or six-hole dynamic compression plate. A below-elbow splint was applied for two weeks. Statistical comparisons were carried out using paired and unpaired t-tests. Differences were considered to be significant for p < Results Clinical evaluation. Table IV summarises the clinical outcome at follow-up. In the CW group, six of the 11 patients were free from pain and the remaining five had mild wrist pain on strenuous activity. All patients in the RS group were free from pain in the wrist. In both groups, no patient had pain in the distal radio-ulnar joint or at the site of the osteotomy. The postoperative range of extension and flexion of the wrist significantly increased only in the CW group. The grip strength of the affected side, compared with that of the contralateral unaffected side, improved significantly after both procedures. After lateral closing wedge osteotomy all patients except one were able to resume previous sports and work activities. No statistically significant differences were found in the mean clinical scores of either group. According to the modified criteria of Nakamura et al, 5 a good or excellent outcome was achieved in all patients of both groups. There were six excellent and five good results in the CW group and seven excellent and two good results in the RS group. There were no serious complications after either procedure. Radiological evaluation. In the CW group, the mean radial inclination decreased from 27.3 before to 14.4 after operation. After radial shortening, the mean ulnar variance increased from to mm. Bony union at the site of the osteotomy was achieved within three months in all patients. Radiological improvement, indicating lunate revascularisation, developed in one patient in the CW group and in four in the RS group (Fig. 1). Progression of joint narrowing at the radioscaphoid joint was found in two patients in the CW group (Fig. 2). Table V summarises the altered radiological parameters after each operation. After lateral closing wedge osteotomy, the radioscaphoid angle significantly increased and Ståhl s index significantly THE JOURNAL OF BONE AND JOINT SURGERY

3 RADIAL OSTEOTOMY FOR LATE-STAGE KIENBÖCK S DISEASE 675 Table IV. Clinical outcome (mean ± SD) after either a lateral closing wedge (CW) osteotomy or a radial shortening (RS) At diagnosis At follow-up CW group Range of wrist extension/flexion arc of the wrist in degrees 91.8 ± ± 29.6* Percentage grip strength of unaffected side 62.5 ± ± 19.4* Clinical score 16.0 ± 3.9 RS group Range of wrist extension/flexion arc of the wrist in degrees 95.0 ± ± 27.9 Percentage grip strength of unaffected side 42.1 ± ± 22.2 Clinical score 17.1 ± 3.0 * p < 0.05 at diagnosis compared with follow-up p < at diagnosis compared with follow-up Fig. 1a Fig. 1b Fig. 1c Preoperative AP (a) and lateral (b) radiographs of a 17-year-old girl with stage-iiib Kienböck's disease on the right side and an AP radiograph (c) 30 months after radial shortening with improvement of cystic changes in the diseased lunate. Fig. 2a Fig. 2b Fig. 2c A 47-year-old man with stage-iiib Kienböck's disease on the right side. Preoperative AP (a) and lateral (b) radiographs and an AP radiograph (c) at 29 months after a lateral closing wedge osteotomy of 15 with progression of joint narrowing at the radioscaphoid joint. VOL. 84-B, NO. 5, JULY 2002

4 676 N. IWASAKI, A. MINAMI, N. OIZUMI, N. SUENAGA, H. KATO, M. MINAMI Table V. Changes of radiological parameters (mean ± SD) after either a lateral closing wedge (CW) osteotomy or radial shortening (RS) At diagnosis At follow-up CW group Radioscaphoid angle in degrees 68.7 ± ± 10.3* Stähl s index 0.31 ± ± 0.06 Carpal height ratio 0.51 ± ± 0.05 RS group Radioscaphoid angle in degrees 67.3 ± ± 7.2 Stähl s index 0.29 ± ± 0.10 Carpal height ratio 0.48 ± ± 0.04 * p < 0.05 at diagnosis compared with follow-up p < at diagnosis compared with follow-up decreased, but after radial shortening there were no significant changes in any radiological parameter. Discussion Although a number of studies have reported acceptable clinical results after radial osteotomies for Kienböck s disease, the outcome of these procedures remains uncertain in the treatment of advanced stages of this disease Our study showed good or excellent clinical results after both types of radial osteotomy for stage IIIB and stage IV of Kienböck s disease. In addition, we found radiological improvement of the lunate in one patient in the CW group and four patients in the RS group. Degenerative changes at the radioscaphoid joint and progression of scaphoid malrotation were observed only after lateral closing wedge osteotomy. These radiological findings indicate that lateral closing wedge osteotomy does not prevent the radiological progression of advanced Kienböck s disease. The clinical results suggest, however, that both osteotomies are effective in stage IIIB and stage IV of Kienböck s disease. Several experimental studies have suggested that radial shortening can unload the lunate by moving the load towards the distal ulna. 21,22,27 Werner et al, 21 using a cadaver model, showed that relative lengthening of the ulna by 2.5 mm transferred the load on the lunate from the radiolunate to the ulnolunate articulation. Horii et al, 27 using a two-dimensional rigid-body spring model, also showed an increased ulnar load after simulating a lengthening of the ulna by 4 mm. Tsumura et al, 23,24 however, reported that a lateral closing wedge osteotomy reduced the load on the lunate by increasing the load on the radioscaphoid joint without increasing the load on the ulnocarpal space. These biomechanical data indicate that the lateral closing wedge osteotomy shifts the compressive load radially. Our radiological findings also suggest that this osteotomy moves the load from the lunate to the scaphoid. Using CT osteo-absorptiometry, we have shown that the load was moved radially with progression of Kienböck s disease in living subjects. 28 On the basis of these results, there is a relatively high probability of progressive degeneration of the joints adjacent to the scaphoid after a lateral closing wedge osteotomy. The choice of surgical procedure for stage-iiib Kienböck s disease remains controversial. In Lichtman s radiological classification, stage-iiib wrists are defined as having gross collapse of the lunate with fixed rotation of the scaphoid. Some biomechanical studies have emphasised that correction of malrotation of the scaphoid is a critical factor in reducing the excessive force on the lunate. 29,30 Therefore, radial osteotomies, which cannot correct the scaphoid rotation, have been thought to be ineffective for stage-iiib cases. Condit et al 17 showed that the clinical outcome was not good after radial shortening when the preoperative radioscaphoid angle was greater than 60. This suggests that malrotation of the scaphoid was a negative predictive factor regarding the outcome of stage-iii Kienböck s disease treated by this operation. By contrast, in all four wrists which Weiss et al 10 analysed the clinical and functional results of radial shortening for stage-iiib cases were excellent, despite the lack of radiological improvement. Our results also showed a major decrease in wrist pain, as well as improved movement of the wrist and grip strength after radial osteotomy. The procedures which we describe are relatively simple, with few postoperative complications. Relief from pain with acceptable functional improvement after radial osteotomy must be advantageous when compared with that achieved after limited intercarpal fusion or proximal row carpectomy. In spite of radiological progression after lateral closing wedge osteotomies, both radial osteotomies were successful in reducing pain in the wrist and improving function, even in patients with advanced stages of Kienböck s disease. Because of the relatively short follow-up period, degenerative changes at the radioscaphoid joint may develop later without affecting the postoperative clinical result. Since there was only one stage-iv patient in each surgical group, we cannot evaluate the outcome of radial osteotomy for this stage. In our stage-iv patients there were only early generalised degenerative changes in the carpus, and therefore we suggest that radial osteotomy should be carried out THE JOURNAL OF BONE AND JOINT SURGERY

5 RADIAL OSTEOTOMY FOR LATE-STAGE KIENBÖCK S DISEASE 677 only for stage-iv wrists with early changes. A more extensive study is required. In spite of the significant limitations mentioned above, our study has shown the effectiveness of radial osteotomy for the treatment of patients with advanced Kienböck s disease. 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. References 1. Eaton RG. Excision and fascial interposition arthroplasty in the treatment of Kienböck s disease. Hand Clin 1993;9: Kato H, Usui M, Minami A. Long-term results of Kienböck s disease treated by excisional arthroplasty with a silicone implant or coiled palmaris longus tendon. J Hand Surg [Am] 1986;11: Nahigian SH, Li CS, Richey DG, Shaw DT. The dorsal flap arthroplasty in the treatment of Kienböck s disease. J Bone Joint Surg [Am] 1970;52-A: Almquist EE, Burns JF. Radial shortening for the treatment of Kienböck s disease: a 5- to 10-year follow-up. J Hand Surg 1982;7: Nakamura R, Tsuge S, Watanabe K, Tsunoda K. Radial wedge osteotomy for Kienböck s disease. J Bone Joint Surg [Am] 1991;73-A: Rock MG, Roth JH, Martin L. Radial shortening osteotomy for treatment of Kienböck s disease. J Hand Surg [Am] 1991;16: Salmon J, Stanley JK, Trail IA. Kienböck s disease: conservative management versus radial shortening. J Bone Joint Surg [Br] 2000;92-B: Trail IA, Linscheid RL, Quenzer DE, Scherer PA. Ulnar lengthening and radial recession procedures for Kienböck s disease: long-term clinical and radiographic follow-up. J Hand Surg [Br] 1996;21: Watanabe K, Nakamura R, Horii E, Miura T. Biomechanical analysis of radial wedge osteotomy for the treatment of Kienböck s disease. J Hand Surg [Am] 1993;18: Weiss APC, Weiland AJ, Moore JR, Wilgis EFS. Radial shortening for Kienböck s disease. J Bone Joint Surg [Am] 1991;73-A: Minami A, Kimura T, Suzuki K. Long-term results of Kienböck s disease treated by triscaphe arthrodesis and excisional arthroplasty with a coiled palmaris longus tendon. J Hand Surg [Am] 1994;19: Pisano SM, Peimer CA, Wheeler DR, Sherwin F. Scaphocapitate intercarpal arthrodesis. J Hand Surg [Am] 1991;16-A: Sennwald GR, Ufenast H. Scaphocapitate arthrodesis for the treatment of Kienböck s disease. J Hand Surg [Am] 1994;20: Watson HK, Monacelli DM, Milford RS, Ashmead D. Treatment of Kienböck s disease with scaphotrapezio-trapezoid arthrodesis. J Hand Surg [Am] 1996;21: Hori Y, Tamai S, Okuda H, et al. Blood vessel transplantation to bone. J Hand Surg [Am] 1979;4: Hulten O. Über anatomische Variationen der Handgelenkknochen: Ein Beitrag zur Kenntnis der Genese zewi verschiedener Mondbeinveranderungen. Act Radiol 1928;9: Condit DP, Idler RS, Fischer TJ, Hastings H II. Preoperative factors and outcome after lunate decompression for Kienböck s disease. J Hand Surg [Am] 1993;18: Masear VR, Zook EG, Pichora DR, et al. Strain-gauge evaluation of lunate unloading procedures. J Hand Surg [Am] 1992;17: Matsushita K, Firrell JC, Tsai TM. X-ray evaluation of radial shortening for Kienböck s disease. J Hand Surg [Am] 1992;17: Trumble T, Glisson RR, Seaber AV, Urbaniak JR. A biomechanical comparison of the methods for treating Kienböck s disease. J Hand Surg [Am] 1986;11: Werner FW, Palmer AK, Fortino MD, Short WH. Force transmission through the distal ulna: effect of ulna variance, lunate fossa angulation, and radial and palmar tilt of the distal radius. J Hand Surg [Am] 1992;17: Werner FW, Palmer AK. Biomechanical evaluation of operative procedures to treat Kienböck s disease. Hand Clin 1993;9: Tsumura H, Himeno S, Kojimo T, Kido M. Biomechanical analysis of Kienböck s disease. Seikeigeka 1982;33: Tsumura H, Himeno S, An KN, Cooney WP, Chao EYS. Biomechanical analysis of Kienböck s disease. Orthop Trans 1987;11: Alexander AH, Lichtman DM. Kienböck s disease. In: Lichtman DM, ed. The wrist and its disorders. Philadelphia: WB Saunders, 1988: Ståhl F. On lunatemalacia (Kienböck s disease): a clinical and roentgenological study, especially on its pathogenesis and the late results of immobilization treatment. Acta Chir Scand 1947:Suppl Horii E, Garcia-Elias M, Bishop AT, et al. Effect on force transmission across the carpus in procedures used to treat Kienböck s disease. J Hand Surg [Am] 1990;15: Iwasaki N, Minami A, Miyazawa T, Kaneda K. Force distribution through the wrist joint in patients with different stages of Kienböck s disease: using computed tomography osteoabsorptiometry. J Hand Surg [Am] 2000;25: Iwasaki N, Genda E, Minami A, Kaneda K, Chao EY. Force transmission through the wrist joint in Kienböck s disease: a twodimensional theoretical study. J Hand Surg [Am] 1998;23: Short WH, Werner FW, Fortino MD, Palmer AK. Distribution of pressures and forces on the wrist after simulated intercarpal fusion and Kienböck s disease. J Hand Surg [Am] 1992;17: VOL. 84-B, NO. 5, JULY 2002