Total knee arthroplasty with retention of both cruciate ligaments - A nineto eleven-year follow-up study

Background: Although many early designs of total knee arthroplasty allowed the retention of both cruciate ligaments, in most current designs of knee r eplacement systems, either both cruciate ligaments are removed or the poste rior cruciate ligament alone is retained. This report is a review of a seri es of total knee arthroplasties in which both cruciate ligaments were retai ned. Methods: The results of 163 total knee arthroplasties (130 patients) in whi ch both cruciate ligaments were retained were assessed prospectively, One h undred and seven knees (eighty-nine patients) were followed for an average of ten years. There were thirty-four men and ninety-six women, and the aver age age at the time of the index arthroplasty was sixty-seven years (range, forty-two to eighty-four years). The diagnosis was osteoarthritis in 122 ( 75 percent) of the knees and rheumatoid arthritis in forty-one (25 percent) , Twenty-six knees had a valgus deformity, 109 had a varus deformity, and t wenty-eight had a normal alignment of 5 to 10 degrees of valgus, The anteri or cruciate ligament was relatively normal in ninety-six knees and was part ly degenerated in sixty-seven knees. With use of the rating system of the Knee Society, all 163 knees were prosp ectively evaluated at yearly intervals; fifty-six of these knees (in forty- one patients) were followed in this manner until the patient died or was lo st to follow-up. Results: One hundred and four (97 percent) of the 107 knees available for s tudy at an average of ten years had an excellent or good result. At the tim e of the latest follow-up, pain was adequately relieved in ninety-seven kne es (91 percent) and the average range of flexion was 107 +/- 12.6 degrees ( range, 65 to 135 degrees), Ninety-five knees (89 percent) had normal antero posterior stability (less than five millimeters of movement in this plane), and twelve knees (11 percent) had five to ten millimeters of movement as d emonstrated by the drawer sign, Ninety-six knees (90 percent) had normal me diolateral stability, and eleven (10 percent) had 5 to 10 degrees of laxity . Ninety-four knees (88 percent) had valgus alignment of 5 to 10 degrees, T he average knee score was 91 +/- 8.4 points (range, 54 to 100 points), and the average functional score was 82 +/- 21 (range, 10 to 100 points), The s urvival rate at ten years, with revision as the end point, was 95 +/- 2.0 p ercent. Seven (4 percent) of the 163 knees in this series were revised. There were no revisions for patellar problems or aseptic loosening of the tibial compo nent. Conclusions: The good anteroposterior stability in this series after an ave rage follow-up period of ten years indicates that both the anterior and the posterior cruciate ligaments, even when partly degenerated, remain functio nal when they are preserved in a total knee arthroplasty.