Knee Arthroplasty without Metal Augmentations in Patients with Major Tibial Defects: A Retrospective Study

Background: Knee arthroplasty procedures improve pain, function, stability, and appearance of the limb. Total knee arthroplasty (TKA) in severe, long-standing osteoarthritis (OA) with large medial tibial defects could be a challenge. This paper looks at TKA outcomes when large tibial defects are managed without metal wedges or stems.

Methods: TKA cases done for OA with tibial defects of 15-25 mm, without any metal wedge or stem from 2004 to 2017 by a single surgeon in Shiraz, Iran, were clinically and radiographically evaluated. The preoperative questionnaires of SF36, WOMAC, KSS, and radiographs were compared with the follow-up assessments of the same parameters. Data were analyzed by R programming language using student t test, ANOVA, and Kruskal-Wallis. P<0.05 was considered significant.

Results: 91 knees in 72 patients at 65.99±8.66 years of age and 8.28±2.58 years follow-up were studied. The tibial defects were managed with extra tibial cuts and adjustment of tibial component position in all, and the addition of structural autograft in 14 knees. 89 (98%) knees survived with a knee society score (KSS) of 79.4±17.6 and were significantly functioning well (P<0.001). Two knees required revision surgery. Significant improvement in outcome measurements was seen in all cases (P<0.001). No radiographic loosening, alignment change, or clinical instability was detected. The tibial plateau reconstruction without bone grafting and the ones that had autologous bone grafting had similar functional results and radiographic outcomes.

Conclusion: TKA with tibial defects of 15-25 mm treated with a semi-constrained posterior-cruciate ligament (PCL) sacrificing condylar prosthesis without any metal wedges or stem extensions with or without additional autogenous bone graft obtained very good functional and radiographic outcome and 97% survival in 6-17 years follow-up.