What is the role of cemented fixation in total knee arthroplasty? The two-year results of a randomized RSA controlled trial

Aims For many designs of total knee arthroplasty (TKA) it remains unclear whether cemented or uncemented fixation provides optimal long-term survival. The main limitation in most studies is a retrospective or non-comparative study design. The same is true for comparative trials looking only at the survival rate as extensive sample sizes are needed to detect true differences in fixation and durability. Studies using radiostereometric analysis (RSA) techniques have shown to be highly predictive in detecting late occurring aseptic loosening at an early stage. To investigate the difference in predicted long-term survival between cemented, uncemented, and hybrid fixation of TKA, we performed a randomized controlled trial using RSA. Methods A total of 105 patients were randomized into three groups (cemented, uncemented, and hybrid fixation of the ACS Mobile Bearing (ACS MB) knee system, implantcast). RSA examinations were performed on the first day after surgery and at scheduled follow-up visits at three months, six months, one year, and two years postoperatively. Patient-reported outcome measures (PROMs) were obtained preoperatively and after two years follow-up. Patients and follow-up investigators were blinded for the result of randomization. Results RSA secondary stabilization did not show a significant difference between the three types of fixation. A maximum total point motion of less than 0.2 mm in the second postoperative year was shown in each group, which suggests stabilization of the implant. At 24 months after surgery, PROMs significantly improved compared to baseline in all treatment groups. No significant difference was observed between the three groups. Conclusion Secondary stabilization measurements in this study demonstrated no significant difference between the groups. In all groups migration stabilized after initial settling of the implant. For this implant the long-term outcome is not expected to be influenced by the type of fixation to the bone. Cite this article: Bone Joint J 2021;103-B(1):98–104.

Hybrid Fixation for Danis-Weber Type C Fractures With Syndesmosis Injury

Background: This study aimed to assess the clinical and radiological outcomes of hybrid fixation for Danis-Weber type C ankle fractures with a syndesmotic injury. Methods: From January 2016 to April 2018, we retrospectively reviewed consecutive patients who underwent hybrid fixation for Danis-Weber type C ankle fractures with syndesmotic injury with a minimum follow-up of 12 months. We excluded patients who achieved syndesmosis stability after fracture fixation. In all patients, we allowed partial weightbearing at 4 weeks postoperatively. We evaluated the visual analog scale for ankle pain, the Olerud-Molander ankle score, and the American Orthopaedic Foot & Ankle Society score. Malreduction of the syndesmosis was defined based on 2 previously reported methods. Fourteen patients (11 men and 3 women) were included in this study. There were 11 patients with pronation external rotation-type fractures and 3 patients with Maisonneuve fractures. The average age at operation was 37.2 years (range, 18-70 years). Results: Clinical scores were significantly improved at the last follow-up. Postoperative malreduction was observed only in 1 patient (7.1%). Conclusion: Hybrid fixation using a suture-button device combined with a syndesmotic screw in Danis-Weber type C fractures with syndesmosis injury showed a high accuracy of reduction, a low rate of diastasis, and favorable clinical outcomes. This combined method could be a good alternative treatment option for Danis-Weber type C ankle fractures with a syndesmosis injury. Level of Evidence: Level IV, case series.