PMID- 32023233 OWN - NLM STAT- MEDLINE DCOM- 20210519 LR - 20221005 IS - 1528-1132 (Electronic) IS - 0009-921X (Print) IS - 0009-921X (Linking) VI - 478 IP - 9 DP - 2020 Sep TI - Are There Differences in Micromotion on Radiostereometric Analysis Between Bicruciate and Cruciate-retaining Designs in TKA? A Randomized Controlled Trial. PG - 2045-2053 LID - 10.1097/CORR.0000000000001077 [doi] AB - BACKGROUND: Bicruciate-retaining TKA has been proposed to improve clinical outcomes by maintaining intrinsic ACL function. However, because the unique design of the bicruciate-retaining tibial component precludes a tibial stem, fixation may be compromised. A radiostereometric analysis permits an evaluation of early migration of tibial components in this setting, but to our knowledge, no such analysis has been performed. QUESTIONS/PURPOSES: We performed a randomized controlled trial using a radiostereometric analysis and asked, at 2 years: (1) Is there a difference in tibial implant migration between the bicruciate-retaining and cruciate-retaining TKA designs? In a secondary analysis, we asked: (2) Is there a difference in patient-reported outcomes (Oxford Knee Score [OKS] and Forgotten Joint Score [FJS] between the bicruciate-retaining and cruciate-retaining TKA designs? (3) What is the frequency of reoperations and revisions for the bicruciate-retaining and cruciate-retaining TKA designs? METHODS: This parallel-group trial (ClinicalTrials.gov: NCT01966848) randomized 50 patients with an intact ACL who were eligible to undergo TKA to receive either a bicruciate-retaining or cruciate-retaining TKA. Patients were blinded to treatment allocation. The primary outcome was the maximum total point motion (MTPM) of the tibial component measured with model-based radiostereometric analysis (RSA) at 2 years postoperatively. The MTPM is a translation vector defined as the point in the RSA model that has the greatest combined translation in x-, y- and z-directions. A 1-year postoperative mean MTPM value of 1.6 mm has been suggested as a threshold for unacceptable increased risk of aseptic loosening after both 5 and 10 years. The repeatability of the MTPM was found to be 0.26 mm in our study. Patient-reported outcome measures were assessed preoperatively and at 2 years postoperatively with the OKS (scale of 0-48, worst-best) and FJS (scale of 0-100, worst-best). Baseline characteristics did not differ between groups. At 2 years postoperatively, RSA images were available for 22 patients who underwent bicruciate-retaining and 23 patients who underwent cruciate-retaining TKA, while patient-reported outcome measures were available for 24 patients in each group. The study was powered to detect a 0.2-mm difference in MTPM between groups (SD = 0.2, significance level = 5%, power = 80%). RESULTS: With the numbers available, we found no difference in MTPM between the bicruciate-retaining and cruciate-retaining groups. The median (interquartile range [IQR]) MTPM was 0.52 mm (0.35 to 1.02) and 0.42 mm (0.34 to 0.70) in the bicruciate-retaining and cruciate-retaining groups, respectively (p = 0.63). There was no difference in the magnitude of improvement in the OKS from preoperatively to 2 years postoperative between the groups (median delta [IQR] for bicruciate-retaining 18 [14 to 23] versus cruciate-retaining 18 [15 to 21], difference of medians 0; p = 0.96). Likewise, there was no difference in the magnitude of improvement in the FJS score from preoperatively to 2 years postoperative between the groups (mean +/- SD for bicruciate-retaining 46 +/- 32 versus cruciate-retaining 48 +/- 16, mean difference, 2; p = 0.80). Three patients in the bicruciate-retaining group underwent arthroscopically assisted manipulation at 3 to 4 months postoperatively, and one patient in the bicruciate-retaining group sustained a tibial island fracture during primary surgery and underwent a revision procedure after 6 months. There were no reoperations or revisions in the cruciate-retaining group. CONCLUSIONS: With the numbers available, we found no differences between the bicruciate-retaining and the cruciate-retaining implants in terms of stable fixation on RSA or patient-reported outcome measure scores at 2 years, and must therefore recommend against the routine clinical use of the bicruciate-retaining device. The complications we observed with the bicruciate-retaining device suggest it has an associated learning curve and the associated risks of novelty with no demonstrable benefit to the patient; it is also likely to be more expensive in most centers. Continued research on this implant should only be performed in the context of controlled trials. LEVEL OF EVIDENCE: Level II, therapeutic study. FAU - Troelsen, Anders AU - Troelsen A AD - A. Troelsen, L. H. Ingelsrud, M. G. Thomsen, K. S. Otte, H. Husted, Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. FAU - Ingelsrud, Lina Holm AU - Ingelsrud LH AD - A. Troelsen, L. H. Ingelsrud, M. G. Thomsen, K. S. Otte, H. Husted, Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. FAU - Thomsen, Morten Grove AU - Thomsen MG AD - A. Troelsen, L. H. Ingelsrud, M. G. Thomsen, K. S. Otte, H. Husted, Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. FAU - Muharemovic, Omar AU - Muharemovic O AD - O. Muharemovic, Department of Radiology, Centre for Functional and Diagnostic Imaging and Research Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. FAU - Otte, Kristian Stahl AU - Otte KS AD - A. Troelsen, L. H. Ingelsrud, M. G. Thomsen, K. S. Otte, H. Husted, Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. FAU - Husted, Henrik AU - Husted H AD - A. Troelsen, L. H. Ingelsrud, M. G. Thomsen, K. S. Otte, H. Husted, Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. LA - eng SI - ClinicalTrials.gov/NCT01966848 PT - Journal Article PT - Randomized Controlled Trial PL - United States TA - Clin Orthop Relat Res JT - Clinical orthopaedics and related research JID - 0075674 SB - IM CIN - Clin Orthop Relat Res. 2020 Sep;478(9):2054-2056. PMID: 32106135 MH - Aged MH - Arthroplasty, Replacement, Knee/*instrumentation MH - Female MH - Foreign-Body Migration/*diagnostic imaging/etiology MH - Humans MH - Knee Prosthesis/*adverse effects MH - Male MH - Middle Aged MH - Osteoarthritis, Knee/surgery MH - Patient Reported Outcome Measures MH - Prosthesis Design/*adverse effects MH - Prosthesis Failure MH - Radiostereometric Analysis MH - Reoperation/*statistics & numerical data MH - Single-Blind Method MH - Tibia/surgery MH - Treatment Outcome PMC - PMC7431269 COIS- All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research(R) editors and board members are on file with the publication and can be viewed on request. EDAT- 2020/02/06 06:00 MHDA- 2021/05/20 06:00 PMCR- 2021/09/01 CRDT- 2020/02/06 06:00 PHST- 2020/02/06 06:00 [pubmed] PHST- 2021/05/20 06:00 [medline] PHST- 2020/02/06 06:00 [entrez] PHST- 2021/09/01 00:00 [pmc-release] AID - 00003086-202009000-00017 [pii] AID - CORR-D-19-01058 [pii] AID - 10.1097/CORR.0000000000001077 [doi] PST - ppublish SO - Clin Orthop Relat Res. 2020 Sep;478(9):2045-2053. doi: 10.1097/CORR.0000000000001077.