Abstract
Introduction
Total elbow arthroplasty (TEA) is a widely accepted for the treatment for damaged rheumatoid elbows to achieve sufficient joint function. The current prospective study reports the long term follow-up of TEA with an unlinked stem type (Stemmed Kyocera type I, SKC-I) with a solid trochlea on patients who have rheumatoid arthritis (RA). SKC-1 is derived from an unlinked surface replacement prosthesis using polycrystalline alumina ceramics on high-density polyethylene (Kyocera type I), which was developed in 1979, based on the measurement study on the cadaveric elbows.
Materials and Methods
57 elbows (Larsen’s grade IV and V) from 45 RA patients replaced by SKC-1 were investigated. Cement fixation was used in all cases. The duration of follow-up ranged from 36 to 154 (average 73. 7) months. The clinical condition of each elbow before and after operation was assessed according to the scoring system of Japanese Orthopaedic Association (JOA) elbow scoring system (maximum 100 points), which is composed of scores for pain, activity of daily life, muscle strength, range of motion, instability, and deformity of the joint. On the basis of this system, the results are defined as excellent (90–100 points), good (75–89), fair (60–74), and poor (< 60). Radiographic loosening was defined as a progressive radiolucent line of more than two millimeters that completely surrounded the prosthesis.
Results
The average postoperative JOA score improved from 43. 5±10. 2° to 81. 0±}10. 3°, with marked pain relief. The mean range of motion (ROM) of extension/flexion before the surgery was –35. 7±}22. 4/117. 1±}19. 1° and at last follow-up was −17 5±}12. 7/136. 3±}11. 4°. The mean ROM of pronation /supination improved from 51. 1±}23. 4/56. 5±}28. 5° to 78. 3±}16. 8/82. 3±}16. 5°. Of the 57 elbows, 9 elbows were judged to have excellent results, 37 had good results, 8 had fair results, and 3 had poor results.
There were no instances of ulnar nerve palsy, triceps avulsion, or postoperative infection. Medial or lateral epicondylar fracture occurred in 2 cases during the operation, and union was achieved 3 months later. Massive instability with joint dislocation was seen in 3 cases of mutilans arthritis, resulting in poor results. Aseptic loosening was seen in 3 elbows. Revision surgery was performed in 1 case of accidental post-operative distal humerus fracture, and in another of olecranon fracture with the breakage of the ulnar component. With loosening defined as the end point, Kaplan-Meier curve of the cumulative probability of survivorship demonstrates the likelihood of survival of the prosthesis at 93. 8 percent for as long as 10 years.
Discussion
The results of the current study showed a high reliability of the SKC-1 prosthesis with the novel alumina ceramic component over a long period when implanted with cement. However, the use of non-constrained devices is limited by the amount of bone and by the need for ligamentous stability. If soft tissues are damaged along with marked bone loss or inflammatory changes, the ligament should be repaired or a semiconstrained type of prosthesis is indicated. It is important to note that a high level of surgical technique is required for TEA in RA elbows to avoid typical postoperative complications.
