Effect of knee joint weight change on knee function recovery and gait after total knee arthroplasty.

BACKGROUND: Knee osteoarthritis (KOA) is a common disease based on degenerative pathological changes. Total knee arthroplasty (TKA) is an effective treatment for end-stage of KOA. However, only volume adaptation can be achieved with current knee prostheses, and it is difficult to achieve weight adaptation. This study focused on the weight difference of knee joints and initially explored the impact of this change on knee joint functional recovery and gait changes in patients after surgery. METHODS: From October 2015 to June 2019, patients who underwent primary unilateral TKA were enrolled in this prospective cohort study with the same brand of knee prostheses. General data were collected from patients who met the criteria. The resected bone and soft tissues were collected and weighed precisely during TKA, and multivariate regression analysis was used to determine the factors affecting the weight of the removed knee tissues. We compared the weight of excised tissues and the total weight of the knee prosthesis, and the weight difference was defined as the increased weight of the knee joint (IWKJ). All patients were evaluated by HSS score, gait analysis, and affected side knee X-ray at two weeks, three months, and the last follow-up after the operation. To further determine the influence of IWKJ on postoperative functional recovery, the relationship between IWKJ, HSS score, and gait analysis was analyzed by univariate regression. RESULTS: In total, 210 patients were eventually included in observation. All patients underwent postoperative follow-up for no less than two years. Multiple regression analysis showed that the course of the disease, body weight, and kellgren-Larencen stage(K-L stage)of the affected knee joint were independent factors affecting the weight of the removed knee tissues and were positively correlated with it. Univariate analysis showed that IWKJ was negatively correlated with HSS score at two weeks and three months after the operation. In addition, the values of spatiotemporal parameters and knee rotation ROM were negatively correlated with IWKJ two weeks after surgery, while outside food load response was positively correlated with IWKJ. Cadence, knee rotation ROM, and Ankle rotation ROM were negatively correlated with IWKJ, while outside food was positively correlated with IWKJ three months after surgery. At the last follow-up, only the hip rotation ROM was positively correlated with IWKJ. CONCLUSIONS: All Patients underwent TKA had varying degrees of increased knee weight. The increased weight was 298.98 ± 63.77 g. Patients' body weight, K-L staging, and disease duration are important factors that cause differences in resected knee tissue. Three months after the operation, the changes in knee joint weight had a negative correlation with the HSS score, which at the same time, it had varying degrees of linearity with gait parameters. However, the influence of weight diminished over time.

Comparison of long-term clinical outcomes after bilateral mobile-bearing total knee arthroplasties using PCL-retaining and PCL-substituting implants in the same patients.

PURPOSE: Whether the posterior cruciate ligament (PCL) should be retained or substituted in total knee arthroplasty (TKA) remains an issue of concern. The purpose of this study was to perform within-patient comparisons of mid- and long-term clinical outcomes after mobile-bearing TKA using PCL-retaining (PCLR) and PCL-substituting (PCLS) implant designs. METHODS: Clinical outcomes were assessed in thirty-eight patients (76 knees) who underwent bilateral scheduled staged TKA with a PCLR design on one side and a PCLS design on the other. Median follow-up periods were 118 months (range 60-211) and 114 months (62-198) in knees with PCLR and PCLS implants, respectively. The preoperative diagnosis for all patients was osteoarthritis. The postoperative clinical results of mobile-bearing TKAs using PCLR and PCLS implant designs were evaluated. RESULTS: The postoperative Hospital for Special Surgery and the new Knee Society Knee Scoring System scores revealed no differences between PCLR and PCLS implant designs. Postoperative flexion and extension also did not differ between designs. Postoperative median femorotibial alignment was 4° for PCLR and 5° for PCLS implants, respectively; this difference was not significant. Six of the knees with PCLR and three of the knees with PCLS implants had radiolucent lines around the tibial prostheses; these were less than 1 mm and nonprogressive. CONCLUSIONS: Clinically good results were obtained at approximately 10 years after mobile-bearing TKA using both PCLR and PCLS implant designs bilaterally in the same patients. These results provide conclusive evidence that equivalent clinical results can be obtained with either implant design. LEVEL OF EVIDENCE: Therapeutic study, Level II.