Comparison of two types of ulnar component in type-5 Kudo total elbow arthroplasty in patients with rheumatoid arthritis: a long-term follow-up

The purpose of this study was to assess the long-term results (more than ten years) of two types of cemented ulnar component with type-5 Kudo total elbow arthroplasty in a consecutive series of 56 patients (60 elbows) with rheumatoid arthritis, and to compare the results in elbows above and below a Larsen grade IV. There was no radiolucency around the humeral component. Patients in whom a metal-backed ulnar component and a porous-coated stem were used had better clinical results and significantly less progression of radiolucent line formation around the ulnar component. They also had a significantly better long-term survival than patients with an all-polyethylene ulnar component. The clinical results of arthroplasty using all-polyethylene ulnar components were inferior, regardless of the degree of joint destruction. We conclude that the type-5 Kudo total elbow arthroplasty with cementless fixation of the porous-coated humeral component and cemented fixation of a metal-backed ulnar component is acceptable and well-tolerated by rheumatoid patients.     

Constrained total elbow arthroplasty

In 1972, the senior author designed a condylar-sparing constrained hinge elbow prosthesis with a high-density polyethylene bushing. The condylar-sparing design allows both intercondylar and intramedullary fixation of the humeral component with methylmethacrylate cement. Reattachment of the muscles and collateral ligaments to the preserved condyles provides further stability. The clinical experience spans more than 16 years in 42 elbows with a relatively low loosening rate of 7%. The implant was removed and not replaced in three elbows: one for late infection, one for posttraumatic comminuted fracture of the distal humerus, and one for loosening of a humeral component. A series of 27 patients (31 elbows) with 24-204 months of follow-up study (average, 77 months) had excellent pain relief and an average range of motion of 129 degrees flexion, -44 degrees extension, 69 degrees pronation, and 61 degrees supination.     

The Kudo elbow prosthesis in rheumatoid arthritis

The Kudo prosthesis is the most commonly used elbow implant in Sweden. However, there are few reports of the results, besides those reported by Kudo himself. I have implanted 30 Kudo type 4 or 5 elbow prostheses in 28 patients with rheumatoid arthritis. 3 arthroplastics were revised, 2 because of loosening and 1 because of a periprosthetic ulnar fracture. 6 major peroperative or early postoperative complications occurred, but only 1 of these was a failure. 2 patients developed postoperative ulnar neuropathy, one was transient and the other patient died 1 year after surgery. 26 elbows were available for follow-up at an average 5 (2-8) years after implantation. All 26 functioned well although radiographic loosening of the humeral component was found in 1 patient. The average range of flexion increased by 14 degrees while the extension lag was unchanged (35 degrees). Activities of daily living had improved markedly and all but 3 patients were satisfied with their elbow. Radiolucent lines were seen around the proximal part of the ulnar component in 18/26 elbows. Although progressive in 1 patient only, this is a matter of concern, indicating that this component may be the weak part of the Kudo prosthesis.     

The Kudo elbow prosthesis in rheumatoid arthritis: a consecutive series of 26 elbow replacements in 24 patients followed prospectively for a mean of 5 years

The Kudo prosthesis is the most commonly used elbow implant in Sweden. However, there are few reports of the results, besides those reported by Kudo himself. I have implanted 30 Kudo type 4 or 5 elbow prostheses in 28 patients with rheumatoid arthritis. 3 arthroplastics were revised, 2 because of loosening and 1 because of a periprosthetic ulnar fracture. 6 major peroperative or early postoperative complications occurred, but only 1 of these was a failure. 2 patients developed postoperative ulnar neuropathy, one was transient and the other patient died 1 year after surgery. 26 elbows were available for follow-up at an average 5 (2-8) years after implantation. All 26 functioned well although radiographic loosening of the humeral component was found in 1 patient. The average range of flexion increased by 14 degrees while the extension lag was unchanged (35 degrees). Activities of daily living had improved markedly and all but 3 patients were satisfied with their elbow. Radiolucent lines were seen around the proximal part of the ulnar component in 18/26 elbows. Although progressive in 1 patient only, this is a matter of concern, indicating that this component may be the weak part of the Kudo prosthesis.     

Failure mechanisms in uncemented Kudo type 5 elbow prosthesis in patients with rheumatoid arthritis: 7 of 49 ulnar components revised because of loosening after 2-10 years

BACKGROUND: Both components of the Kudo type 5 elbow prosthesis can be inserted with or without the use of cement. There have been no reports on the use of this prosthesis with all components uncemented in patients with rheumatoid arthritis. PATIENTS AND METHODS: We reviewed 49 primary uncemented Kudo type 5 elbow prostheses, inserted in 36 patients with rheumatoid arthritis, after mean 6 (2-10) years. Patients were assessed clinically both pre- and postoperatively (pain, instability, motion, ulnar neuropathy) and radiographically. Furthermore, at the time of follow-up clinical outcome was assessed using the Elbow Function Assessment Scale. RESULTS: At review, 7 of 49 elbows had undergone revision because of symptomatic loosening of the ulnar component. In 42 unrevised elbows, clinical outcome was excellent in 29, good in 7, fair in 5, and poor in one. 31 of 42 elbows had no pain; 11 were painful at rest (VAS 1-2) and/or as a result of activity (VAS 1-8). With revision as endpoint, survival was 86% at 6 years. Intraoperative malpositioning of the ulnar component with a valgus or varus alignment of < 5 degrees was associated with worse survival. INTERPRETATION: We found an unexpectedly high rate of loosening of the ulnar component, which was associated with intraoperative malpositioning of the prosthesis. The ulnar component of this prosthesis should not be inserted without cement in patients with rheumatoid arthritis.     

Total elbow arthroplasty with a non-constrained surface-replacement prosthesis in patients who have rheumatoid arthritis. A long-term follow-up study

Thirty-seven elbows in thirty-six patients who had rheumatoid arthritis had a total elbow arthroplasty with insertion of a non-constrained surface-replacement prosthesis. The patients were followed for an average of nine years and six months, the longest follow-up being seventeen years. A good result was seen in twenty-nine elbows; a fair result, in one; and a poor result, in seven. The reasons for the poor results were gross posterior displacement of the humeral component in five elbows, persistent subluxation with pain in one, and recurrent ankylosis in one. Of the five elbows that had gross posterior displacement, four had a revision operation with a new humeral component, and a satisfactory result was eventually achieved. Radiographic examination revealed various degrees of proximal subsidence of the humeral component in 70 per cent of the elbows. However, in most of the elbows the subsidence was not progressive and was compatible with a good clinical result. In contrast, the rate of loosening of the ulnar component was low; loosening was seen in only 5 per cent of the elbows. Seventeen elbows were followed for ten years or more, and comparison of the clinical results in the intermediate period with those at the most recent review revealed that the results improved with time. Because of the number of elbows in which subsidence of the humeral component developed, we now use a humeral component with an intramedullary stem, and were no longer recommend the use of our Type-1 and Type-2 prostheses.     

GSB III total elbow replacement in rheumatoid arthritis

Between 1993 and 2002, 58 GSB III total elbow replacements were implanted in 45 patients with rheumatoid arthritis by the same surgeon. At the most recent follow-up, five patients had died (five elbows) and six (nine elbows) had been lost to follow-up, leaving 44 total elbow replacements in 34 patients available for clinical and radiological review at a mean follow-up of 74 months (25 to 143). There were 26 women and eight men with a mean age at operation of 55.7 years (24 to 77). At the latest follow-up, 31 excellent (70%), six good (14%), three fair (7%) and four poor (9%) results were noted according to the Mayo elbow performance score. Five humeral (11%) and one ulnar (2%) component were loose according to radiological criteria (type III or type IV). Of the 44 prostheses, two (5%) had been revised, one for type-IV humeral loosening after follow-up for ten years and one for fracture of the ulnar component. Seven elbows had post-operative dysfunction of the ulnar nerve, which was transient in five and permanent in two. Despite an increased incidence of loosening with time, the GSB III prosthesis has given favourable mid-term results in patients with rheumatoid arthritis.     

Radial head replacement in capitellocondylar total elbow arthroplasty. 2- to 6-year follow-up evaluation in rheumatoid arthritis

We reviewed six capitellocondylar metal-to-plastic total elbow replacement prostheses with radial head components, implanted in patients with rheumatoid arthritis. At an average of 4.7 +/- 1.5 years, relief of pain, improvement of function, and a functional range of motion were preserved. Five of the six elbows (83%) were clinically rated good or excellent. Radiolucent lines were seen at the bone-cement interface in 50% of the humeral component stems and in all ulnar component boats within 2 years after surgery; none had progressed at subsequent examination. Most were less than or equal to 1 mm wide, and none were associated with clinical deterioration. Only one of the humeral components was radiographically loose. No radiolucent lines were seen along the stems of the ulnar or radial components. There were no postoperative dislocations when the radial component was used, presumably because the prosthetic radial head provided increased constraint. None of these elbows have required revision. Radial head replacement in capitellocondylar arthroplasty had been discontinued because radiolucent lines were observed at early review. However, the absence of clinical failure, dislocation, or progression of radiolucency at long-term follow-up examination favor radial head replacement in primary unconstrained total elbow arthroplasty.     

A review of the Liverpool elbow prosthesis from 1974 to 1982

Eighty elbows in 65 patients with an average age of 57 years have had two-part non-constrained Liverpool elbow arthroplasties performed since 1974. Fifty-five had rheumatoid arthritis, eight osteoarthritis or ankylosis secondary to injury, one osteochondritis dissecans and one pyknodysostosis. The average preoperative range of movement was 42 degrees to 112 degrees with 47 degrees of pronation and 42 degrees of supination. There was significant gain in the arc of movements at follow-up: 32 degrees in the extension-flexion range (average range 32 degrees to 134 degrees of flexion) and 42 degrees in forearm rotation (average pronation 69 degrees and supination 62 degrees). Before operation severe pain was the predominating symptom in 43 elbows (53.8%) but after replacement there was only moderate pain in five elbows (6.2%). The results were excellent in 42 (52.5%), good in 15 (18.7%), fair in 9 (11.3%) and unsatisfactory or poor in 14 (17.5%). Eight elbows required revision of the arthroplasty: three were post-traumatic, disorganised or osteoarthritic joints, three rheumatoid and both elbows in the patient with pyknodysostosis. Loosening of the prosthesis (particularly the humeral component) was the common factor necessitating revision. Of six rheumatoid elbows needing removal of the implant, four had deep infection, one had a dislodged humeral component as a result of injury and in one a divided olecranon had developed non-union. Rheumatoid elbows benefited more than post-traumatic arthritic elbows from the operation. (ABSTRACT TRUNCATED AT 250 WORDS)     

Kinematics and laxity of the Souter-Strathclyde total elbow prosthesis

The motion pattern and laxity of 8 cadaveric elbows were recorded with a 3-dimensional electromagnetic tracking device before and after the Souter-Strathclyde total elbow prosthesis was implanted. The Souter-Strathclyde prosthesis replicates the valgus-varus motion pattern of the intact elbow but causes a significant internal rotation of the ulnar shaft of 8.9 degrees +/- 4.1 degrees (P < .0005) at 110 degrees of elbow flexion. One of the reasons for this unphysiological motion pattern is positioning of the humeral component in a mean of 5.4 degrees +/- 6.4 degrees of external rotation compared with the intact elbow (P = .05). This positioning is related to the design of this device. The Souter-Strathclyde elbow prosthesis has a mean maximum valgus-varus laxity of 6.5 degrees +/- 1.5 degrees compared with 4.3 degrees +/- 2.3 degrees for the intact elbow (P = .004). This implant is more constrained than previously tested devices, which may explain its relatively higher loosening rate.     

Micromotion of the Souter-Strathclyde total elbow prosthesis in patients with rheumatoid arthritis 21 elbows followed for 2 years

21 elbows in 18 patients with rheumatoid arthritis were treated with a Souter-Strathclyde total elbow prosthesis. 18 elbows were included in a radiostereometry (RSA) study. The aim of this clinical RSA study was to assess the three-dimensional micromotion pattern of the Souter-Strathclyde prosthesis, and thereby gain insight in the aseptic loosening process of this prosthesis. Implants were defined as at risk of aseptic loosening when the translation rate during the second postoperative year was more than 0.4 mm along one or more coordinate axes and/or the rate of rotation was more than 1 degrees about one or more coordinate axes. Clinical examination revealed an increase in the range of motion and a marked reduction in pain. The RSA showed that 8 of 18 humeral components were at risk of aseptic loosening, although no signs of such loosening-defined as a complete radiolucent line of 2 mm or more-were found on the plain radiographs. In 7 humeral components, an anterior tilt about the transverse axis was seen that resulted in an anterior translation of the proximal tip and a posterior translation of the component's trochlea. Long-term studies of the Souter-Strathclyde prosthesis, have shown that this rotation is a specific pattern of failure in some implants. None of the ulnar components was at risk for aseptic loosening. Improvements in fixation of the Souter-Strathclyde total elbow arthroplasty should focus on the humeral component. At present, the lateral flange of the implant is enlarged to improve rotational stability about the transverse and longitudinal axes. The effect of this change in design on micromotion of the Souter-Strathclyde total elbow prosthesis will be studied in a randomized RSA study comparing the new design to the existing one.     

Allograft-prosthesis composite for revision of catastrophic failure of total elbow arthroplasty

BACKGROUND: Revision of a failed total elbow arthroplasty is a challenging procedure, often associated with bone deficiency. The purpose of this investigation was to review our experience with a composite allograft-implant reconstruction for patients with a failed total elbow arthroplasty. METHODS: Thirteen patients (thirteen elbows) in whom a total elbow arthroplasty had failed, primarily as a result of loosening of the humeral or ulnar component, were operated on with use of an allograft-prosthesis composite; the composite was placed on the humeral side in four of these patients and on the ulnar side in nine. The delay between the last total elbow arthroplasty and the allograft-prosthesis-composite procedure averaged eight years. RESULTS: At an average of forty-two months after the revision, the Mayo Elbow Performance Score was excellent for four elbows, good for three, fair for one, and poor for five. Nine of the thirteen patients had no or only slight pain in the elbow. The mean arc of flexion was 97 degrees, with an average of 28 degrees (range, 0 degrees to 60 degrees ) of extension to 125 degrees (range, 100 degrees to 140 degrees ) of flexion. There were seven complications affecting seven elbows, and five of the seven required a revision procedure. Deep infection developed in four elbows, and the allograft-prosthesis composite had to be removed from three. Two nonunions occurred at the allograft-humeral junction. CONCLUSIONS: An allograft-prosthesis composite can be a valuable option in selected patients with a failed total elbow arthroplasty with massive bone loss. The union and implant survival rates are high. Deep infection remains the main complication. Hence, we recommend the pursuit of other revision options, such as strut graft reconstruction, whenever possible before resorting to the use of an allograft-prosthesis composite in the surgical treatment of a failed total elbow arthroplasty with massive bone loss.     

Total elbow arthroplasty as primary treatment for distal humeral fractures in elderly patients

Distal humeral fractures are difficult to treat. In the elderly population, the problems are compounded by osteoporosis and gross comminution. Open reduction and internal fixation for such fractures is sometimes difficult and may be associated with poor results. Total elbow arthroplasty has been suggested as a last-ditch effort to salvage functional use for such difficult fractures in the elderly. We followed seven patients (seven elbows) with a mean age of 81.7 years at the time of injury. Open reduction and internal fixation was considered a difficult option for these fractures. They were treated with a total elbow arthroplasty using the semi-constrained Coonrad-Morrey elbow replacement prosthesis. The duration of follow up at present is between 2 and 4 years. At the latest follow up the mean arc of flexion is 20-130 degrees. Six patients have no pain while one complains of mild pain. All elbows are stable. The Mayo elbow performance score for five elbows is excellent and two scored good. All but one patient are satisfied with the result. One patient developed superficial wound infection which resolved after antibiotic therapy. One patient has developed post-operative triceps weakness. There have been no cases of deep infection, ulnar nerve neuritis or component failure. The rarity of this procedure suggests its very narrow spectrum of indication. We feel that the short-term results do suggest an important role for semi-constrained total elbow arthroplasty in managing carefully selected comminuted distal humeral fractures in the elderly, especially those that cannot be treated by conventional open reduction and internal fixation.     

Total elbow prosthesis loosening caused by ulnar component pistoning

BACKGROUND: Linked semiconstrained total elbow prostheses have been used successfully but may be at higher risk for implant loosening than unlinked implants are. The purpose of the present report was to describe a previously unreported and potentially preventable cause of mechanical loosening of the ulnar component of a linked total elbow prosthesis. METHODS: A series of ten patients who had painful pistoning of the polymethylmethacrylate-coated ulnar component of a Coonrad-Morrey linked total elbow prosthesis were evaluated clinically and radiographically. RESULTS: All ten patients complained of elbow pain, and eight had a distinct sensation of the ulnar component moving within the ulna. Six patients either complained of squeaking within the elbow or could demonstrate squeaking on examination. Four patients had a complete radiolucent line around the ulnar component or the cement mantle, and six had an incomplete line around the ulnar component. Six patients had a radiolucent gap between the cement and the tip of the ulnar prosthesis. Two patients had proximal migration of the ulnar component within the cement mantle on lateral flexion radiographs. Three patients had anterior impingement, such as between the anterior flange of the humeral implant and a prominent coronoid process, on lateral flexion radiographs. At the time of revision arthroplasty, all ten patients were found to have a loose ulnar component, which was successfully revised with or without impaction grafting. At the time of the most recent follow-up, nine of the ten ulnar components were intact and stable. Three patients required an additional reoperation: one required triceps repair, one required revision of a loose humeral component, and one required a revision total elbow arthroplasty. CONCLUSIONS: Pistoning of the ulnar component in the cement mantle leading to failure by means of a pullout mechanism can occur in association with the Coonrad-Morrey total elbow prosthesis with a polymethylmethacrylate-precoated ulnar component. To prevent this problem following any total elbow arthroplasty, the surgeon should check for anterior impingement intraoperatively by ensuring that there is no contact between the anterior flange and a prominent coronoid process or the cement and that no distraction of the trial ulnar component from the ulna occurs with passive elbow flexion. This condition also can be avoided by ensuring that the ulnar component is not inserted too far distally. This mechanism of failure should be considered when future total elbow arthroplasty implants are designed. LEVEL OF EVIDENCE: Therapeutic Level IV.     

Kudo total elbow arthroplasty in patients with rheumatoid arthritis: a long-term follow-up study.

BACKGROUND: Improvements in the design of total elbow prostheses over the last two decades have led to better and more consistent results. The type-3 Kudo total elbow prosthesis was developed in 1980. The long-term results of use of this implant have not been reported. Because it is an unlinked prosthesis, it is not known whether preservation of the anterior oblique component of the ulnar collateral ligament at the time of implantation is important. METHODS: A type-3 Kudo total elbow arthroplasty with cement was performed in forty-seven patients (fifty elbows) with rheumatoid arthritis. Revision rates, clinical symptoms, postoperative complications, and radiographic changes were assessed eleven to sixteen years (mean, thirteen years) postoperatively. RESULTS: The overall survival rate of the prosthesis was 90% at sixteen years. The mean Mayo elbow performance scores were all poor (mean overall score, 43 points) initially. The overall score was substantially improved at both the intermediate follow-up examination (four to six years after the operation) and the late follow-up examination (eleven to sixteen years after the operation), to 81 and 77 points, respectively. The overall rate of radiolucency about the humeral component was 45% at the intermediate follow-up examination and 100% at the long-term follow-up examination. The rate of radiolucency about the ulnar component at the intermediate and late follow-up examinations was 4.3% and 8.9%, respectively. No great differences in results were found with preservation of the anterior oblique component of the ulnar collateral ligament. CONCLUSIONS: This long-term follow-up study showed acceptable results of the type-3 Kudo total elbow arthroplasty in patients with rheumatoid arthritis. Preservation of the ulnar collateral ligament does not seem to be necessary when performing this procedure.     

Five- to thirteen-year follow-up of the GSB III total elbow arthroplasty

Between 1988 and 1995, the senior author performed total elbow arthroplasty in 28 elbows (23 patients) with the GSB III prosthesis. At the most recent follow-up, 7 patients had died (9 elbows) and 1 had the implant removed because of a deep infection. The remaining 18 elbows (15 patients) were available for clinical and radiographic review at a mean period of 7.6 years (range, 5.5-11.9 years). All 15 patients were satisfied with the results of their elbow replacement, with a mean Mayo elbow performance score of 91 (range, 75-100). The mean flexion/extension and supination/pronation arcs improved by 33 degrees and 67 degrees, respectively. Radiographic follow-up demonstrated progressive loosening in only 1 patient and no progressive loosening in those with an adequate cement technique. Mild or moderate lysis of the distal humeral or proximal ulnar components was noted in 10 elbows, and severe lysis of the distal humerus was seen in 1. Of the patients, 6 (21%) had mild complications: triceps avulsions in 3, superficial wound infections in 2, and an undisplaced fracture of the distal humeral medial condyle in 1. In 4 patients (14%) complications developed requiring reoperation, including exchange of the polyethylene bushing because of wear, debridement of synovitis, resection arthroplasty for deep infection, and exploration of an ulnar nerve palsy. In 2 additional patients (7%), persistent ulnar nerve paresthesias developed postoperatively. Of the 28 elbow replacements performed with the GSB III prosthesis, only 1 required revision because of loosening at a mean follow-up of 7.6 years. The results of this series of GSB III elbow replacements in patients with rheumatoid arthritis demonstrate reasonable survivorship of this prosthesis.     

Capitellocondylar total elbow replacement. A long-term follow-up study.

Fifty-one capitellocondylar elbow replacements were inserted in forty-one patients between 1976 and 1986. Thirty-nine patients had rheumatoid arthritis and two had traumatic osteoarthrosis. The average age of the patients at the time of the operation was fifty-six years (range, twenty-one to seventy-seven years). Thirty-one patients who had thirty-nine retained elbow prostheses had an average length of follow-up of 6.5 years (range, two to thirteen years). Flexion improved an average of 20 degrees; extension, 4 degrees; pronation, 22 degrees; and supination, 36 degrees. Relief of pain was complete in 85 per cent of the thirty-nine elbows, and in 15 per cent there was only mild pain. Noteworthy postoperative complications in the original fifty-one elbows included infection in four elbows (8 per cent), dislocation in three (6 per cent), and ulnar neuropathy in sixteen (31 per cent). Three elbows were revised: one for a humeral fracture, one for recurrent dislocation, and one for aseptic loosening. Aseptic loosening was evident on radiographs of two elbows; one patient was completely asymptomatic, and one had mild pain with deformity. The Souter zonal radiographic assessment system for identification of radiolucencies at the bone-cement interface was utilized; there was no significant difference in radiolucencies between ulnar components backed with metal and those that were not backed with metal. Kaplan-Meier cumulative survivorship analysis demonstrated that a functional prosthesis was retained in 88 per cent of the elbows at 1.4 years postoperatively and in 83 per cent at 5.5 years.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surface replacement of the elbow in rheumatoid arthritis. Early results with the Wadsworth prosthesis

Fifteen patients with rheumatoid arthritis had 19 elbow arthroplasties with the Wadsworth type of surface replacement prosthesis. After a follow-up period averaging 30 months, 11 patients with 15 elbow arthroplasties were entirely satisfied with their freedom from pain and range of movement. Radiologically, however, the humeral component was loose in 10 of the 19 elbows and the ulnar component in 5. Two patients had reoperation, one to remove a prosthesis for early deep infection and one to exchange a humeral component which was loose. The risk of mechanical loosening is reduced by accurate positioning of the humeral component, but there is a high potential for failure. Changes in the design of the prosthesis and better instrumentation for alignment of the components are desirable. Prosthetic replacement of the elbow should still be regarded as experimental.     

Failure mechanisms in uncemented Kudo type 5 elbow prosthesis in patients with rheumatoid arthritis: 7 of 49 ulnar components revised because of loosening after 2–10 years

Background?Both components of the Kudo type 5 elbow prosthesis can be inserted with or without the use of cement. There have been no reports on the use of this prosthesis with all components uncemented in patients with rheumatoid arthritis.

Patients and methods?We reviewed 49 primary uncemented Kudo type 5 elbow prostheses, inserted in 36 patients with rheumatoid arthritis, after mean 6 (2–10) years. Patients were assessed clinically both pre- and postoperatively (pain, instability, motion, ulnar neuropathy) and radiographically. Furthermore, at the time of follow-up clinical outcome was assessed using the Elbow Function Assessment Scale.

Results?At review, 7 of 49 elbows had undergone revision because of symptomatic loosening of the ulnar component. In 42 unrevised elbows, clinical outcome was excellent in 29, good in 7, fair in 5, and poor in one. 31 of 42 elbows had no pain; 11 were painful at rest (VAS 1–2) and/or as a result of activity (VAS 1–8). With revision as endpoint, survival was 86% at 6 years. Intraoperative malpositioning of the ulnar component with a valgus or varus alignment of < 5° was associated with worse survival.

Interpretation?We found an unexpectedly high rate of loosening of the ulnar component, which was associated with intraoperative malpositioning of the prosthesis. The ulnar component of this prosthesis should not be inserted without cement in patients with rheumatoid arthritis.