Bicruciate-retaining Total Knee Replacement Provides Satisfactory Function and Implant Survivorship at 23 Years

Clin Orthop Relat Res (2015) 473:2327–2333 DOI 10.1007/s11999-015-4219-8 Clinical Orthopaedics and Related Research® A Publication of The Association of Bone and Joint Surgeons® CLINICAL RESEARCH Bicruciate-retaining Total Knee Replacement Provides Satisfactory Function and Implant Survivorship at 23 Years James W. Pritchett MD Received: 24 September 2014 / Accepted: 18 February 2015 / Published online: 27 February 2015 Ó The Association of Bone and Joint Surgeons1 2015 Abstract Background One of the goals of a TKA is to approximate the function of a normal knee. Preserving the natural ligaments might provide a method of restoring close to normal function. Sacrifice of the ACL is common and practical during a TKA. However, this ligament is functional in more than 60% of patients undergoing a TKA and kinematic studies support the concept of bicruciateretaining (that is, ACL-preserving) TKA; however, relatively few studies have evaluated patients treated with bicruciate-retaining TKA implants. Questions/purposes I asked: (1) what is the long-term (minimum 20-year) survivorship, (2) what are the functional results, and (3) what are the reasons for revision of bicruciate-retaining knee arthroplasty prostheses? Methods From January 1989 to September 1992, I performed 639 total knee replacements in 537 patients. Of Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. The author certifies that his institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. J. W. Pritchett (&) 901 Boren Avenue, #900, Seattle, WA 98104, USA e-mail: these, 489 were performed in 390 patients using a bicruciate-retaining, minimally constrained device. During the period in question, this knee prosthesis was used for all patients observed intraoperatively to have an intact, functional ACL with between 15° varus and 15° valgus joint deformity. There were 234 women and 156 men with a mean age at surgery of 65 years (range, 42–84 years) and a primary diagnosis of osteoarthritis in 89%. The patella was resurfaced in all knees. The mean followup was 23 years (range, 20–24 years). At the time of this review, 199 (51%) patients had died and 31 (8%) patients were lost to followup, leaving 160 (41%) patients (214 knees) available for review. Component survivorship was determined by competing-risks analysis and Kaplan Meier survivorship analysis with revision for any reason as the primary endpoint. Patients were evaluated every 2 years to assess ROM, joint laxity, knee stability, and to determine American Knee Society scores. Results The Kaplan-Meier survivorship was 89% (95% CI, 82%–93%) at 23 years with revision for any reason as the endpoint. Competing-risks survivorship was 94% (95% CI, 91%%–96 %) at 23 years. At followup, the mean age of the patients was 84 years (range, 63–101 years), the mean flexion was 117° (range, 90°–130°), the mean American Knee Society score improved from a preoperative mean of 42 (range, 26–49) to 91 (range, 61–100; p \ .001). Twenty-two knees in 21 patients (5.6%) were revised, most commonly because of polyethylene wear. Conclusions ACL sacrifice may be an unnecessary concession during TKA. This study found satisfactory survivorship and function after more than 20 years of use for patients receiving a bicruciate-retaining TKA implant. A TKA that preserves cruciate ligaments provides a stable, well-functioning knee with a low likelihood of revision at long-term followup. Retaining both cruciate ligaments 123 2328 Pritchett during knee arthroplasty is an attractive concept that is worth considering. Level of Evidence Level IV, therapeutic study. Introduction Normal knee function relies on smooth, uninterrupted motion, which in turn depends on stable, well-lubricated, low-friction articular surfaces. Knee replacement involves compromises between stability and flexibility, and historically has included removal of one or both cruciate ligaments. As an alternative to this philosophy, a bicruciate-retaining knee prosthesis was developed in 1971 [24]. The design emphasized preserving the ligaments, minimizing bone resection, and limiting constraint with the goal of allowing more natural movement of the knee compared with other prostheses. AP stability was provided by the preserved cruciate ligaments rather than the shape of the polyethylene. Although the ACL is functional in more than 60% of patients undergoing a TKA [1, 7, 8] and kinematic studies support the concept of bicruciate-retaining (that is, ACLpreserving) TKA [14, 23], few studies have evaluated patients treated with bicruciate-retaining TKA implants [16–19, 21]. Because of these perceived advantages, I used a bicruciate-retaining TKA implant in my practice for all patients with an intact ACL and acceptable deformity during a 3-year period, and because of the limited number of studies available at longer term [21], I sought to evaluate their performance and durability. I asked: (1) what is the long-term (minimum 20-year) survivorship, (2) what are the functional results, and (3) what are the reasons for revision of a bicruciate-retaining knee arthroplasty? Patients and Methods From January 1989 to September 1992, I performed 639 total knee replacements in 537 patients. Of these, 489 (77%) were performed in 390 patients using a bicruciateretaining, minimally constrained device (Townley Anatomic, Biopro Inc, Port Huron, MI, USA) (Fig. 1). Patients selected for a TKA with a bicruciate-retaining prosthesis had no history of ACL insufficiency. During the period in question, this prosthesis was used for all patients observed intraoperatively to have an intact, functional ACL and limited deformity. There were 156 men (40%) and 234 women (60%) with a mean age at surgery of 65 years (SD, 8.6; range, 42–84 years). The primary diagnosis was osteoarthritis in 347 (89%) knees and inflammatory arthritis or osteonecrosis in 43 (11%). At the time of the 123 Clinical Orthopaedics and Related Research1 surgery, the ACL was functionally intact as shown by testing with a probe and by negative Lachman, pivot shift, and anterior drawer tests. The appearance and integrity of the ACL also was teste (...truncated)