The impact of joint line restoration on functional results after hinged knee prosthesis

Abstract

Background:Hinged knee prosthesis is an effective treatment method as a salvage procedure in marked ligamentous insufficiency and severe bone defects. Joint line determination and restoration are difficult due to large bone defects and distorted anatomy. We evaluated the impact of joint line alteration on the outcome in rotating hinge knee arthroplasty (RHKA).Materials and Methods:35 patients who had rotating hinged knee prosthesis applied between 2008 and 2013 were evaluated in this retrospective study. The patients were studied radiologically and clinically. Five patients were lost to followup and two patients died, leaving a total of 28 (7 male, 21 female) patients for final evaluation. The average age of the patients was 66.19 ± 8.35 years (range 52–83 years). The patients were evaluated clinically with Knee Society knee and functional score and patellar score. The joint line positions were evaluated radiographically with femoral epicondylar ratio method. The outcomes were also evaluated according to age, body weight and gender. Student's t-test, independent t-test, and the Wilcoxon signed rank test were used in the statistical analysis.Results:The mean Knee Society knee and functional score significantly improved from preoperative 19.52 ± 11.77 and 12.5 ± 15.66 respectively to 72.46 ± 14.01 and 70.36 ± 9.22 respectively postoperatively (P < 0.001). The mean range of motion of the knee improved from 55.95° ± 25.08° preoperatively to 92.14° ± 13.47° postoperatively (P < 0.001). Joint line position was restored in 20 patients (71.4%). Joint line alteration did not affect Knee Society Scores (KSSs) in contrast to patellar scores. Additionally, KSS was better in the patients with body mass index ≤30 at followup (P = 0.022 and P = 0.045).Conclusion:RHKA is an effective salvage procedure for serious instability and large bone defects. Restoration of the joint line improves the patellar score although it had no effect on the clinical outcome.

The influence of joint line restoration on functional outcome after primary total knee arthroplasty: A prospective study

“…11 Yilmaz et al showed that restoration of joint line causes improvement in patella score although it had no effect on clinical outcome. 21 Since the basic foundation of TKA is based on soft tissue balancing, appropriate bone cuts, cementing and joint line restoration, it will be prudent to state that aiming to restore the joint line as close to the pre-operative value as possible should be the aim of the operating surgeon to achieve the optimum outcome.…”

Rotating Hinge Knee Arthroplasty for Charcot Joints of the Knees in Patients With Charcot–Marie–Tooth Disease: A Report of Two Cases

“…A variety of implants have been used in TKA for Charcot arthropathy, including cruciate retained (CR), posterior stable (PS), Legacy® constrained condylar knee (LCCK), and RHK. The choice of implants is still controversial [18,19]. Unrestrained components (e.g., CR PS) are often not suitable for Charcot arthropathy because they can cause postoperative joint instability due to severe deformity and soft tissue imbalance [4,18].…”

“…For this reason, LCCK, which provides good stability with minimal restrictions, is considered the preferred implant for Charcot arthropathy by some surgeons [7,8]. RHK is indicated in patients presenting with knee hyperextension because excessive restraint can increase the risk of aseptic loosening and periprosthetic fractures [19,20]. A short-term postoperative follow-up after RHK for Charcot joints secondary to CMT and myasthenia gravis revealed improved knee function [10].…”