Abstract
Object
Although single-radius designs have theoretical advantages in some aspects, there has been a paucity of evaluation studies. The purpose of this study was to compare 10-year clinical, radiological, survivorship outcomes of single radius and multi radius posterior stabilized prosthesis in total knee arthroplasty(TKA) with Rheumatoid Arthritis (RA).
Method
In this retrospective observational study, we reviewed 240 patients (240 knees) with RA who underwent TKA between Oct 2005 and Dec 2007: SR group (120 patients, 120 knees, Stryker Scorpio NRG) and MR group (120 patients, 120 knees, Depuy sigma RP). A 1 : 1 matched case control study was conducted in two groups which were similar in terms of age, gender, BMI, ASA classification and operation team. Mean follow-up periods were 10.73±1.13 (range: 8–13) years and 10.82±1.09 (range: 7–13) years.
Results
In SR group, the mean HSS score improved significantly from 38.63±8.76 to 87.67±6.62, the mean VAS score decreased significantly from 7.37±0.24 to 0.45±0.12. the mean range of motion improved significantly from 105.52°±7.78°to 124.32°±8.12° (p<0.001). In MR group, the mean HSS score improved significantly from 38.75±8.34 to 89.29±5.21, the mean VAS score decreased significantly from 7.62±0.26 to 0.33±0.10. the mean range of motion improved significantly from 104.18°±7.62° to 122.52°±8.03°(p<0.001). (See Figure 1) Clinical and functional improvements had no significant differences between the two groups. 6 complications were noted in SR group, including 2 cases of prosthetic loosening, 1 case of periprosthetic osteolysis, 3 cases of periprosthetic bright lines.6 complications were noted in MR group, including 2 cases of prosthetic loosening and 4 cases of periprosthetic bright lines. No case of infection was observed in two groups. Survivorship using Kaplan-Meier survival analysis was 97.5% (95% confidence interval [CI]: 96.8–98.3%) for the SR at 10 years and 98.3% (95% CI: 97.3–99.5%) for the MR group at 10 years, with no significant difference (p=0.755). (See Figure 2)
Conclusion
This study suggested that both single-radius and multi-radius posterior stabilized prostheses can lead to satisfactory outcomes for clinical function, radiological evaluation and survivorship among RA patients undergoing TKA, and no significantly clinical differences was shown in two types of prostheses.
