Revision Of Unicompartmental Knee Arthroplasty Research Articles

Advances in unicompartmental knee arthroplasty with minimally invasive techniques

Unicompartmental arthroplasty has proved to be a reliable option for monocompartmental arthritis in well selected patients. Unicompartmental knee arthroplasty (UKA) is not a temporary procedure and its ten year survival is comparable to TKA and better than High Tibial Osteotomy. The success of the procedure depends on strict patient selection, meticulous surgical technique and proper implant selection. The renewed interest in UKA is due to improved results, more conservative nature of the procedure, faster rehabilitation, decreased cost and the minimally invasive techniques. The sedentary patient with unicompartmental arthritis is currently the primary indication for UKA. The role of unicompartmental arthroplasty in younger patients needs more investigation. Revision of UKA has not found to be as complicated as reported in the early series. Minimally invasive UKA has shown short term promising results but more long term studies showing similar implant longevity compared with the standard approach are required to establish its role. Due to high level of patient satisfaction and low morbidity and complications compared with TKA, unicompartmental arthroplasty is an attractive option for patients with predominantly unicompartmental non inflammatory arthritis.

Revision of unicompartmental knee arthroplasty: outcome in 1,135 cases from the Swedish Knee Arthroplasty study.

From 1975 through 1995, 45,025 knee arthroplasties were recorded in the prospective Swedish Knee Arthroplasty study. By the end of 1995, 1,135 of 14,772 primary unicompartmental knee arthroplasties (UKA) for localized, mainly medial arthrosis had been revised. The Marmor/Richards and St. Georg sledge/Endo-Link prostheses were used in 65%. Mean age at revision was 72 (71) years. 232 revisions were performed as an exchange UKA (partial in 97) and 750 as a total knee arthroplasty (TKA). 153 were revised by other modes. In medial UKA, the indication for revision was component loosening in 45% and joint degeneration in 25% and in lateral UKA, the corresponding figures were 31% and 35%, respectively. In 94 cases, unicompartmental components were added to the initially untreated compartment, in 14 with partial exchange of a component. The CRRR was estimated using survival statistics. After only 5 years, the risk of having a second revision was more than three times higher for failed UKAs revised to a new UKA (cumulative rerevision rate (CRRR 26%) than for those revised to a TKA (CRRR 7%). This difference remained, even if those revised before 1985, when modern operating technique was introduced, were excluded (CRRR 31% and 5%, respectively). UKA is a safe primary procedure, when performed with well-designed components and modern surgical technique. It gives documented good patient satisfaction, range of motion, pain relief and relatively few serious complications. However, once failed, the knee should be revised to a TKA. This applies to most modes of failure. Not even joint degeneration of the unoperated compartment can be safely treated by adding contralateral components; CRRR after this procedure was 17%, while it was 7% when converted to a TKA.

Cementless AGC revision of unicompartmental knee arthroplasty

Twenty-eight patients (29 knees) who had revision of a failed unicompartmental knee arthroplasty to total knee arthroplasty were evaluated. All revisions were made with cementless technique using the AGC prosthesis (Biomet, Warsaw, IN). Major osseous defects were found in 20 knees, and bone-grafting was used to fill the defects. Aseptic loosening and progression of osteoarthrosis were the main reasons for revision. The median follow-up period was 38 months. Twenty knees were excellent or good, four fair, and five poor. One tibial component had been revised because of loosening. Three knees with instability had been reoperated with a thicker polyethylene component, but one of these patients still suffered from instability, and revision with a constrained prosthesis was planned. One was revised after a deep infection. Two tibial components were suspected to be loose because radiographs exposed fluoroscopically revealed a complete radiolucent line under the component. The results with cementless revision and bone — grafting are comparable to the results achieved after cemented revision, and cementless revision is recommended in young patients and in patients with major bone loss.

Early failure of the porous coated anatomic cemented unicompartmental knee arthroplasty: Aids to diagnosis and revision

Unicompartmental knee arthroplasty (UKA) is performed less frequently than total (tricompartmental) knee arthroplasty (TKA). This study examined the range of presenting symptoms and usefulness of diagnostic tests to determine the failure mode; the outcome of surgical revision of failed UKA is also reported. From a consecutive prospective series of 43 Porous Coated Anatomic (Howmedica, Rutherford, NJ) UKAs performed between 1985 and 1992 and followed for an average of 64 months, 12 cases have come to revision surgery (28%). The average time to failure was 37 months. Symptoms preceded revision surgery by an average of 10 months. The most common presenting symptom was pain (100%), followed by swelling (92%), reduced range of motion (42%), instability (42%), and clicking (17%). Failure was caused by polyethylene wear in 50%, loosening of the femoral component in 42%, and progression of patellofemoral arthritis in one patient. The combination of single leg standing anteroposterior radiographs and supine lateral radiographs detected most causes of UKA failure. A bone scan was confirmatory in every case of suspected loosening of the femoral component. Arthroscopy diagnosed polyethylene wear in two cases and progression of joint arthritis in one case and was not helpful in one case. Revision surgery was done with primary TKA components, and follow-up periods averaged 27 months. Bone stock deficiency was found in 58%, but required bone-grafting in only one case. Revision surgery successfully restored pain-free function and range of motion in all cases. Two-year postrevision Hospital for Special Surgery scores are equal to those for primary TKA. Survivorship analysis showed a 33% failure rate at 57 months after Porous Coated Anatomic UKA when revision was the endpoint and a 41% failure rate when unsatisfactory clinical status was the endpoint. Regular follow-up evaluation is suggested for the Porous Coated Anatomic UKA.