Factors affecting the osteolysis around the components after posterior-stabilized total knee replacement arthroplasty.

Purpose: The purpose of the present study was to evaluate factors that affect the occurrence of osteolysis through clinical and radiological comparison between a patient group in which osteolysis occurred after total knee arthroplasty (TKA) and a patient group in which osteolysis did not occur after TKA.

Methods: The present study was conducted with 486 knees that had been followed up for at least 2 years after undergoing a posterior-stabilized TKA. The subjects were divided into a group in which osteolysis occurred and a group in which osteolysis did not occur and retrospectively compared and analyzed. Knee Society Knee Score and Function Score, preoperative and postoperative range of motion (ROM), femoral and tibial implant positions, preoperative and postoperative femerotibial angles, posterior femoral condylar offset (PCO), level of joint line (JL), and posterior tibial slopes were measured and clinically and radiologically compared.

Results: Osteolysis occurred in 28 knee joints (5.7%). No significant difference was observed between the patient group without osteolysis, and the patient group with osteolysis was observed in preoperative and postoperative ROM, femoral and tibial implant positions, or preoperative and postoperative femerotibial angles. The means of preoperative and postoperative differences in PCO and level of JL were significantly larger in the patient group with osteolysis than in the patient group without osteolysis (p = 0.01, p = 0.007), and regression analyses showed that the means of preoperative and postoperative differences in these two variables were related with the occurrence of osteolysis (p = 0.021, p = 0.018).

Conclusion: The present study shows that biomechanical changes occurring after TKA are related with the occurrence of osteolysis. For clinical relevance, surgeons should pay great attention to restore normal anatomical structure as much as possible with careful preoperative plans, accurate surgical techniques, and selection of appropriate implants.

Level Of Evidence: Retrospective comparative study, Level III.