SILICONE
RUBBER
S. D. SAGERMAN,
DISTAL ULNAR ARTHROPLASTY
J. G. SEILER,
L. L. FLEMING
REPLACEMENT and E. LOCKERMAN
From the Emory University School of Medicine, Department of Orthopaedics, Atlanta, Georgia, USA
We retrospectively reviewed 42 patients who underwent resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis (45 wrists). Two prostheses were used: the original Swanson prosthesis, and a prosthesis of our own design. Follow-up X-rays showed migration or breakage of 63% of the prostheses. No statistically significant correlation existed between the quality of functional outcome and the integrity of the prostheses. There was no significant difference between pre-operative and post-operative range of motion for the entire group or between patients with broken or intact prostheses. Histological confirmation of silicone synovitis was documented in one patient who required implant removal. We suggest that destabilization and breakage of prostheses result from fatigue failure secondary to the torque generated at the distal radio-ulnar joint during repeated pronation and supination. Use of a silicone rubber ulnar head prosthesis following distal ulna resection is not recommended. Journal of Hand Surgery (British Volume, 1992) 17B: 689-693
fibrous ingrowth and a stay suture; this was used in the remaining 27 cases (Fig. 1).
Following early reports of satisfactory clinical results, an integral part of our surgical management of the wrist affected by inflammatory or degenerative arthritis has been resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis, either alone or in conjunction with total wrist arthroplasty. A retrospective review has been carried out to assess the long-term outcome of this procedure.
MATERIAL
RESULTS 19 patients (19 wrists) were available for follow-up at the time of this study, on average 91 months after operation (range 31-129 months). 74% (14 of 19) of these patients experienced significant pain relief. 95% (18 of 19) reported being satisfied with the result. The range of motion was limited in all patients preoperatively and was not significantly improved following the procedure (Table 1). No statistically significant relationship existed between range of motion and the condition of the prosthesis as determined by radiographic examination. Serial X-rays were available for 35 patients (83%). Review of these showed that 22 (63%) of the prostheses had migrated or broken. 13 implants (37%) were stable,
AND METHODS
All patients who underwent resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis at Emory University affiliated hospitals from 1976 to 1986 have been included in this study. Hospital records and clinic notes of all patients were reviewed for pre-operative diagnosis, type of prosthesis, pre-operative range of motion, and length of follow-up. Standard postoperative serial radiographs were reviewed to identify implant loosening, fracture of the prostheses, and maintenance of bone stock in the distal ulna. For clinical follow-up, patients were questioned about pain relief, functional limitations, and overall satisfaction with the procedure. Range of motion was measured. A total of 42 patients (45 wrists) who received a silicone rubber ulnar head prosthesis were reviewed in this study. 15 patients (17 wrists) received a total wrist arthroplasty in conjunction with the distal ulnar prosthesis while the remaining 27 patients (28 wrists) received the ulnar head implant alone. The indications for surgery were rheumatoid arthritis in 35 patients (83x), post-traumatic malunion in five (12x), psoriatic arthritis in one (2x), and Madelung’s deformity in one (2%). The original Swanson prosthesis, constructed of Silastic silicone rubber (Dow Corning Wright, Arlington, Tennessee, USA), was implanted in 18 wrists. A Silflex silicone rubber prosthesis (Sutter Corporation, San Diego, California, USA) was designed, and includes a dacron polyester sleeve for
Fig. 1
689
The original Swanson distal ulnar cap prosthesis (right) was made of silicone rubber. Later designs of this prosthesis included a stay suture to provide immediate fixation (not shown). Our design, the Silflex silicone rubber distal ulnar prosthesis (left), incorporates a stay suture as well as a dacron polyester sleeve to promote fibrous ingrowth into the stem.
690 Table l-Range
THE JOURNAL
OF HAND SURGERY
VOL. 17B No. 6 DECEMBER
1992
of motion for patients with distal ulnar prostheses Pre-
Flexion (degrees) Extension (degrees) Supination (degrees) Pronation (degrees)
39 26 60 64
Post-operative ROM
38 33 64 81
38 35 63 73
ROM = range of motion. a Post-operative range of motion in patients with intact prostheses. b Post-operative range of motion in patients with fractured or migrated prostheses. No statistically significant difference was found between post-operative ROM for those with intact and broken prostheses; paired f-test.
14 (40%) had migrated distally or were significantly angulated, two (6%) were completely dislodged, and six (17%) were fractured. A similar percentage of both the Swanson prosthesis (67%; eight out of 12) and our prosthesis (61%; 14 out of 23) failed radiographically. Of the 17 wrists which had both total wrist and distal ulnar prostheses implanted, a similar percentage (59%) of the distal ulnar prostheses failed. There was no correlation between those patients with subjective complaints of pain and radiographic evidence of prosthetic breakage. Loss of bone stock in the distal ulna occurred commonly in conjunction with prosthetic migration as shown in Figure 2. One patient showed radiographic signs of bone resorption consistent with silicone synovitis and required implant removal (Fig. 3). The prosthesis was found to be broken. Histological examination of the surrounding tissue confirmed a particle-induced foreign body reaction and synovial hyperplasia. DISCUSSION In 1966, the silicone rubber distal ulnar prosthesis was introduced for arthritic conditions of the distal radioulnar joint. The goals were to improve stability following total wrist replacement, preserve function of the extensor carpi ulnaris tendon, prevent subsequent tendon rupture, prevent overgrowth of the distal ulna, and preserve physiological length following resection of the distal ulna (Swanson, 1973). The original design (Fig. 1) included a dome-shaped head and cylindrical intramedullary stem. Swanson’s original report (1973) of 73 implants showed quite favourable results, though the length of follow-up was not given. They produced an increase in grip strength and range of motion, but there was distal migration of the implant in five cases which he attributed to a lack of suitable articulation to support the head of the prosthesis in the early stages of healing. Clinical results were not affected in those patients. Swanson later changed his design by attaching a longitudinally oriented suture to the implant. Our prosthesis was also designed to improve the initial stability of the prosthesis while allowing for fibrous ingrowth into the dacron polyester mesh which covers the stem (Fig. 1). However, in our series, this
Fig. 2
X-ray showing a broken stock in the distal ulna.
Silflex prosthesis
with loss of bone
resulted in no improvement in the incidence of migration and breakage compared to Swanson’s original design. Swanson’s view that virtually all patients benefitted from the prosthesis has not been universally accepted (Swanson, 1973; Kleinert and Lister, 1986). Davis et al (1982) believed that addition of a distal ulnar prosthesis contributed to stability following total wrist replacement, provided that capsular reconstruction was performed. Goodman et al (1980) left the decision to use a prosthesis to the surgeon’s preference but also stressed the need for satisfactory reconstruction of the joint capsule. Fatti et al (1986) reported a high incidence of breakage of the prosthesis and have since abandoned its use. McMurtry et al (1990) recently published a follow-up study of the distal ulnar prosthesis in rheumatoid and
Fig. 3
(a) The wrist of a 50-year-old female patient with rheumatoid arthritis and a failed Swanson ulnar head prosthesis, (b) X-ray, three years after operation, showing fracture of the prosthesis and angulation of the head of the prosthesis. (c) Photograph of the prosthesis as it appeared after removal. Note fragmentation of the head and fracture at the junction of the head with the stem. (d) Histological section of synovial tissue specimen taken when the fractured implant was removed, showing a foreign body giant cell reaction to silicone rubber particles (arrow).
692
non-rheumatoid wrist deformities. Although 78% of their patients experienced satisfactory results for pain and function, radiographic examination revealed a 20% incidence of prosthetic fracture as well as progressive osteolysis of the distal ulna. As in our study, they found no significant difference in any radiographic parameter between those patients with satisfactory and unsatisfactory subjective results, and they have abandoned the use of the Swanson prosthesis except in elderly patients with rheumatoid arthritis. A recent study in rheumatoid patients found no advantage in the use of the prosthesis compared with resection of the distal ulna alone (White, 1986). Five out of seven prostheses were significantly tilted, and their use was complicated by a bone-resorptive process resulting from a foreign body reaction. Although infrequent, this process has been histologically confirmed by other authors (Kleinert and Lister, 1986; McMurtry et al, 1990). Our study documents a case of histologically proven siliconeinduced synovitis which necessitated implant removal. Moreover, several of the patients in White’s series required re-operation for implant migration and pain associated with bone resorption. Our study supports his finding that implant instability and migration is a common occurrence. The fact that, in our study, a broken and/or migrated prosthesis provided the same functional outcome as an intact prosthesis supports White’s conclusion that there is no benefit from the use of the prosthesis compared to simple resection of the distal ulna. His description of silicone synovitis associated with implant arthroplasty provides a very plausible explanation to account for prosthetic loosening and instability which we observed in our series. We believe that failure of the prosthesis may result from the repetitive stresses occurring at the distal radioulnar joint. The cause of migration and fracture of ulnar head prosthesis could result from the shear loads imposed upon the prosthesis by torque generated during supination and pronation of the forearm (Fig. 4). Because the hemispherical head of the prosthesis is not adequately stabilized, it twists in response to this torque, generating shear strain in the material of the prosthesis. Depending on the quality of fixation of the stem in the medullary canal, the prosthesis either fractures or migrates. McMurtry et al (1990) frequently observed pistoning of the prosthesis as it moved distally with supination and proximally with pronation. This finding is consistent with our hypothesis on implant failure. As suggested by Beabout and Linscheid (1986), proper orientation of a prosthesis in relation to the bone in which it is implanted does not guarantee proper functioning in the normal arc of motion. Capsular and ligamentous laxity resulting from bone and soft tissue resection at the time of implantation may produce radio-ulnar joint instability, and thus contribute additional stresses on the implant. Our finding that the most common site of fracture was at the junction of the head and stem, where maximum shear stress is produced, supports our theory.
THE
JOURNAL
Fig. 4
OF HAND
SURGERY
VOL.
17B No. 6 DECEMBER
1992
Supination and pronation generate torque on the head of the prosthesis. Depending on the fixation of the stem in the medullary canal, the prosthesis either fractures or migrates in response to this torque.
Others (Bowers, 1985; Watson et al, 1986; Tulipan et al, 1991) have described the use of hemiresection of the distal ulna in combination with a soft tissue rebalancing procedure as an alternative to implantation of a silicone rubber prosthesis. Currently, we are doing this with a tenodesis utilizing the extensor carpi ulnaris for distal ulnar stabilization. Acknowledgement The authors wish to thank Marian Miller for editorial Cline for preparation of the manuscript.
assistance
and Deborah
References BEABOUT. J. W. and LINSCHEID. R. L. (1986). Total ioint arthroolastv of hands and wrists. Seminars in Roentgenoiogy, il : 1: 86-89. I ’ BOWERS, W. H. (1985). Distal radioulnarjoint arthroplasty: The hemiresectioninterposition technique. The Journal of Hand Surgery, 10A: 2: 169-178. DAVIS, R. F., WEILAND, A. J. and DOWLING, S. V. (1982). Swanson implant arthroplasty of the wrist in rheumatoid patients. Clinical Orthopaedits and Related Research, 166: 132-137. FATTI, J. F., PALMER, A. K. and MOSHER, J. F. (1986). The long-term results of Swanson silicone rubber interpositional wrist arthroplasty. Journal ofHand Surgery, 11A: 2: 166-175. GOODMAN, M. J., MILLENDER, L. H., NALEBUFF, E. A. and PHILIPS, C. A. (1980). Arthroplasty of the rheumatoid wrist with silicone rubber: An early evaluation. Journal of Hand Surgery, 5: 2: 114-121. KLEINERT, .I. M. and LISTER, G. D. (1986). Silicone implants. Hand Clinics, 2: 2: 271-290. McMURTRY. R. Y.. PALEY. D.. MARKS. P. and AXELROD. T. (1990). A , critical analysis of Swanson ulnar head replacement arthroplasty: Rheumatoid versus nonrheumatoid. Journal of Hand Surgery, 15A : 2: 224-23 1. I
DISTAL
ULNAR
693
ARTHROPLASTY
SWANSON, A. B. (1973). Implant arthroplasty for disabilities of the distal radioulnarjoint : Use of a silicone rubber capping implant following resection of the ulnar head. Orthopedic Clinics of North America, 4: 2: 373-382. TULIPAN, D. .I., EATON, R. G. and EBERHART, R. E. (1991). The Darrach procedure defended: Technique redefined and long-term follow-up. Journal of Hand Surgery, 16A : 3 : 438-444. WATSON, H. K., RYU, J. and BURGESS, R. C. (1986). Matched distal ulnar resection. Journalof Hand Surgery, 1lA: 6: 812-817.
WHITE, R. E. (1986). Resection of the distal ulna with and without implant arthroplasty in rheumatoid arthritis. Journal of Hand Surgery, 1IA: 4: 514518. Accepted: 13 February 1992 J G. Seller III, Emory University School of Medicine. Department Street, SE, Atlanta, Georgia 30303, USA. 0 1992 The British Society for Surgery of the Hand
ofOrthopaedics,
69 Butler
RUBBER
S. D. SAGERMAN,
DISTAL ULNAR ARTHROPLASTY
J. G. SEILER,
L. L. FLEMING
REPLACEMENT and E. LOCKERMAN
From the Emory University School of Medicine, Department of Orthopaedics, Atlanta, Georgia, USA
We retrospectively reviewed 42 patients who underwent resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis (45 wrists). Two prostheses were used: the original Swanson prosthesis, and a prosthesis of our own design. Follow-up X-rays showed migration or breakage of 63% of the prostheses. No statistically significant correlation existed between the quality of functional outcome and the integrity of the prostheses. There was no significant difference between pre-operative and post-operative range of motion for the entire group or between patients with broken or intact prostheses. Histological confirmation of silicone synovitis was documented in one patient who required implant removal. We suggest that destabilization and breakage of prostheses result from fatigue failure secondary to the torque generated at the distal radio-ulnar joint during repeated pronation and supination. Use of a silicone rubber ulnar head prosthesis following distal ulna resection is not recommended. Journal of Hand Surgery (British Volume, 1992) 17B: 689-693
fibrous ingrowth and a stay suture; this was used in the remaining 27 cases (Fig. 1).
Following early reports of satisfactory clinical results, an integral part of our surgical management of the wrist affected by inflammatory or degenerative arthritis has been resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis, either alone or in conjunction with total wrist arthroplasty. A retrospective review has been carried out to assess the long-term outcome of this procedure.
MATERIAL
RESULTS 19 patients (19 wrists) were available for follow-up at the time of this study, on average 91 months after operation (range 31-129 months). 74% (14 of 19) of these patients experienced significant pain relief. 95% (18 of 19) reported being satisfied with the result. The range of motion was limited in all patients preoperatively and was not significantly improved following the procedure (Table 1). No statistically significant relationship existed between range of motion and the condition of the prosthesis as determined by radiographic examination. Serial X-rays were available for 35 patients (83%). Review of these showed that 22 (63%) of the prostheses had migrated or broken. 13 implants (37%) were stable,
AND METHODS
All patients who underwent resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis at Emory University affiliated hospitals from 1976 to 1986 have been included in this study. Hospital records and clinic notes of all patients were reviewed for pre-operative diagnosis, type of prosthesis, pre-operative range of motion, and length of follow-up. Standard postoperative serial radiographs were reviewed to identify implant loosening, fracture of the prostheses, and maintenance of bone stock in the distal ulna. For clinical follow-up, patients were questioned about pain relief, functional limitations, and overall satisfaction with the procedure. Range of motion was measured. A total of 42 patients (45 wrists) who received a silicone rubber ulnar head prosthesis were reviewed in this study. 15 patients (17 wrists) received a total wrist arthroplasty in conjunction with the distal ulnar prosthesis while the remaining 27 patients (28 wrists) received the ulnar head implant alone. The indications for surgery were rheumatoid arthritis in 35 patients (83x), post-traumatic malunion in five (12x), psoriatic arthritis in one (2x), and Madelung’s deformity in one (2%). The original Swanson prosthesis, constructed of Silastic silicone rubber (Dow Corning Wright, Arlington, Tennessee, USA), was implanted in 18 wrists. A Silflex silicone rubber prosthesis (Sutter Corporation, San Diego, California, USA) was designed, and includes a dacron polyester sleeve for
Fig. 1
689
The original Swanson distal ulnar cap prosthesis (right) was made of silicone rubber. Later designs of this prosthesis included a stay suture to provide immediate fixation (not shown). Our design, the Silflex silicone rubber distal ulnar prosthesis (left), incorporates a stay suture as well as a dacron polyester sleeve to promote fibrous ingrowth into the stem.
690 Table l-Range
THE JOURNAL
OF HAND SURGERY
VOL. 17B No. 6 DECEMBER
1992
of motion for patients with distal ulnar prostheses Pre-
Flexion (degrees) Extension (degrees) Supination (degrees) Pronation (degrees)
39 26 60 64
Post-operative ROM
38 33 64 81
38 35 63 73
ROM = range of motion. a Post-operative range of motion in patients with intact prostheses. b Post-operative range of motion in patients with fractured or migrated prostheses. No statistically significant difference was found between post-operative ROM for those with intact and broken prostheses; paired f-test.
14 (40%) had migrated distally or were significantly angulated, two (6%) were completely dislodged, and six (17%) were fractured. A similar percentage of both the Swanson prosthesis (67%; eight out of 12) and our prosthesis (61%; 14 out of 23) failed radiographically. Of the 17 wrists which had both total wrist and distal ulnar prostheses implanted, a similar percentage (59%) of the distal ulnar prostheses failed. There was no correlation between those patients with subjective complaints of pain and radiographic evidence of prosthetic breakage. Loss of bone stock in the distal ulna occurred commonly in conjunction with prosthetic migration as shown in Figure 2. One patient showed radiographic signs of bone resorption consistent with silicone synovitis and required implant removal (Fig. 3). The prosthesis was found to be broken. Histological examination of the surrounding tissue confirmed a particle-induced foreign body reaction and synovial hyperplasia. DISCUSSION In 1966, the silicone rubber distal ulnar prosthesis was introduced for arthritic conditions of the distal radioulnar joint. The goals were to improve stability following total wrist replacement, preserve function of the extensor carpi ulnaris tendon, prevent subsequent tendon rupture, prevent overgrowth of the distal ulna, and preserve physiological length following resection of the distal ulna (Swanson, 1973). The original design (Fig. 1) included a dome-shaped head and cylindrical intramedullary stem. Swanson’s original report (1973) of 73 implants showed quite favourable results, though the length of follow-up was not given. They produced an increase in grip strength and range of motion, but there was distal migration of the implant in five cases which he attributed to a lack of suitable articulation to support the head of the prosthesis in the early stages of healing. Clinical results were not affected in those patients. Swanson later changed his design by attaching a longitudinally oriented suture to the implant. Our prosthesis was also designed to improve the initial stability of the prosthesis while allowing for fibrous ingrowth into the dacron polyester mesh which covers the stem (Fig. 1). However, in our series, this
Fig. 2
X-ray showing a broken stock in the distal ulna.
Silflex prosthesis
with loss of bone
resulted in no improvement in the incidence of migration and breakage compared to Swanson’s original design. Swanson’s view that virtually all patients benefitted from the prosthesis has not been universally accepted (Swanson, 1973; Kleinert and Lister, 1986). Davis et al (1982) believed that addition of a distal ulnar prosthesis contributed to stability following total wrist replacement, provided that capsular reconstruction was performed. Goodman et al (1980) left the decision to use a prosthesis to the surgeon’s preference but also stressed the need for satisfactory reconstruction of the joint capsule. Fatti et al (1986) reported a high incidence of breakage of the prosthesis and have since abandoned its use. McMurtry et al (1990) recently published a follow-up study of the distal ulnar prosthesis in rheumatoid and
Fig. 3
(a) The wrist of a 50-year-old female patient with rheumatoid arthritis and a failed Swanson ulnar head prosthesis, (b) X-ray, three years after operation, showing fracture of the prosthesis and angulation of the head of the prosthesis. (c) Photograph of the prosthesis as it appeared after removal. Note fragmentation of the head and fracture at the junction of the head with the stem. (d) Histological section of synovial tissue specimen taken when the fractured implant was removed, showing a foreign body giant cell reaction to silicone rubber particles (arrow).
692
non-rheumatoid wrist deformities. Although 78% of their patients experienced satisfactory results for pain and function, radiographic examination revealed a 20% incidence of prosthetic fracture as well as progressive osteolysis of the distal ulna. As in our study, they found no significant difference in any radiographic parameter between those patients with satisfactory and unsatisfactory subjective results, and they have abandoned the use of the Swanson prosthesis except in elderly patients with rheumatoid arthritis. A recent study in rheumatoid patients found no advantage in the use of the prosthesis compared with resection of the distal ulna alone (White, 1986). Five out of seven prostheses were significantly tilted, and their use was complicated by a bone-resorptive process resulting from a foreign body reaction. Although infrequent, this process has been histologically confirmed by other authors (Kleinert and Lister, 1986; McMurtry et al, 1990). Our study documents a case of histologically proven siliconeinduced synovitis which necessitated implant removal. Moreover, several of the patients in White’s series required re-operation for implant migration and pain associated with bone resorption. Our study supports his finding that implant instability and migration is a common occurrence. The fact that, in our study, a broken and/or migrated prosthesis provided the same functional outcome as an intact prosthesis supports White’s conclusion that there is no benefit from the use of the prosthesis compared to simple resection of the distal ulna. His description of silicone synovitis associated with implant arthroplasty provides a very plausible explanation to account for prosthetic loosening and instability which we observed in our series. We believe that failure of the prosthesis may result from the repetitive stresses occurring at the distal radioulnar joint. The cause of migration and fracture of ulnar head prosthesis could result from the shear loads imposed upon the prosthesis by torque generated during supination and pronation of the forearm (Fig. 4). Because the hemispherical head of the prosthesis is not adequately stabilized, it twists in response to this torque, generating shear strain in the material of the prosthesis. Depending on the quality of fixation of the stem in the medullary canal, the prosthesis either fractures or migrates. McMurtry et al (1990) frequently observed pistoning of the prosthesis as it moved distally with supination and proximally with pronation. This finding is consistent with our hypothesis on implant failure. As suggested by Beabout and Linscheid (1986), proper orientation of a prosthesis in relation to the bone in which it is implanted does not guarantee proper functioning in the normal arc of motion. Capsular and ligamentous laxity resulting from bone and soft tissue resection at the time of implantation may produce radio-ulnar joint instability, and thus contribute additional stresses on the implant. Our finding that the most common site of fracture was at the junction of the head and stem, where maximum shear stress is produced, supports our theory.
THE
JOURNAL
Fig. 4
OF HAND
SURGERY
VOL.
17B No. 6 DECEMBER
1992
Supination and pronation generate torque on the head of the prosthesis. Depending on the fixation of the stem in the medullary canal, the prosthesis either fractures or migrates in response to this torque.
Others (Bowers, 1985; Watson et al, 1986; Tulipan et al, 1991) have described the use of hemiresection of the distal ulna in combination with a soft tissue rebalancing procedure as an alternative to implantation of a silicone rubber prosthesis. Currently, we are doing this with a tenodesis utilizing the extensor carpi ulnaris for distal ulnar stabilization. Acknowledgement The authors wish to thank Marian Miller for editorial Cline for preparation of the manuscript.
assistance
and Deborah
References BEABOUT. J. W. and LINSCHEID. R. L. (1986). Total ioint arthroolastv of hands and wrists. Seminars in Roentgenoiogy, il : 1: 86-89. I ’ BOWERS, W. H. (1985). Distal radioulnarjoint arthroplasty: The hemiresectioninterposition technique. The Journal of Hand Surgery, 10A: 2: 169-178. DAVIS, R. F., WEILAND, A. J. and DOWLING, S. V. (1982). Swanson implant arthroplasty of the wrist in rheumatoid patients. Clinical Orthopaedits and Related Research, 166: 132-137. FATTI, J. F., PALMER, A. K. and MOSHER, J. F. (1986). The long-term results of Swanson silicone rubber interpositional wrist arthroplasty. Journal ofHand Surgery, 11A: 2: 166-175. GOODMAN, M. J., MILLENDER, L. H., NALEBUFF, E. A. and PHILIPS, C. A. (1980). Arthroplasty of the rheumatoid wrist with silicone rubber: An early evaluation. Journal of Hand Surgery, 5: 2: 114-121. KLEINERT, .I. M. and LISTER, G. D. (1986). Silicone implants. Hand Clinics, 2: 2: 271-290. McMURTRY. R. Y.. PALEY. D.. MARKS. P. and AXELROD. T. (1990). A , critical analysis of Swanson ulnar head replacement arthroplasty: Rheumatoid versus nonrheumatoid. Journal of Hand Surgery, 15A : 2: 224-23 1. I
DISTAL
ULNAR
693
ARTHROPLASTY
SWANSON, A. B. (1973). Implant arthroplasty for disabilities of the distal radioulnarjoint : Use of a silicone rubber capping implant following resection of the ulnar head. Orthopedic Clinics of North America, 4: 2: 373-382. TULIPAN, D. .I., EATON, R. G. and EBERHART, R. E. (1991). The Darrach procedure defended: Technique redefined and long-term follow-up. Journal of Hand Surgery, 16A : 3 : 438-444. WATSON, H. K., RYU, J. and BURGESS, R. C. (1986). Matched distal ulnar resection. Journalof Hand Surgery, 1lA: 6: 812-817.
WHITE, R. E. (1986). Resection of the distal ulna with and without implant arthroplasty in rheumatoid arthritis. Journal of Hand Surgery, 1IA: 4: 514518. Accepted: 13 February 1992 J G. Seller III, Emory University School of Medicine. Department Street, SE, Atlanta, Georgia 30303, USA. 0 1992 The British Society for Surgery of the Hand
ofOrthopaedics,
69 Butler
