[10-Year Follow-Up of the NexGen CR Total Knee Prosthesis]

Long-term results of a rotationally unconstrained fixed-bearing total knee prosthesis

PURPOSE

Introduced in the market in 1990 by Ceraver (France), the posterior-stabilised (PS) Hermes prosthesis has limited literature regarding long-term survivability. The purpose of the study is to evaluate the survival and functional outcomes of the prosthesis.

METHODS

A retrospective case series was performed including 164 patients (176 knees) having undergone total knee arthroplasty with the Hermes prosthesis between 1997 and 2000 with a follow-up period of 18 years.

RESULTS

Kaplan-Meier analysis showed a survival rate of 99.4% (95% CI. 96.0-100.0%) at 18.4 years with one revision. At final follow-up, the International Knee Society (IKS) functional score was 93.2 ± 15.6 and IKS knee score was 99.1 ± 2.5.

CONCLUSION

The Hermes PS model is a low conformity prosthesis that offers reliable durability that is comparable to other popular designs while minimizing rotational constraints and having an approachable learning curve for new users.

Midterm results of a new personalized knee implant for total knee arthroplasty: implant survivorship and patient-reported outcome after five years' follow-up

PURPOSE

The Persona® system is a newly launched implant designed for total knee arthroplasty (TKA) with technical innovations intended for a better functional outcome and higher flexion range. The aim of this study is to evaluate midterm outcomes and survivorship of a cohort of patients with a minimum of 5-year follow-up and to confirm previous results described in the literature.

METHODS

A cohort of 91 knees (85 patients) that underwent a patella-preserving TKA with the Persona® implant and who were followed for a mean of 5.9 years' period was included in the study. Functional values were measured: Oxford Knee Score (OKS), Knee Society Knee score (KSKS) and Knee Society Function score (KSFS). Range of movement (ROM), lower limb axis correction, mobilization and complications were also registered at the last follow-up and underwent statistical analysis.

RESULTS

We found a low rate of complications or radiological changes with an implant-related revision rate of 2.19%. Mean results for PROMS were 44.21 ± 4 in OKS, 90.94 ± 2.4 in KSS and 97.88 ± 9.6 in KSFS. Mean postoperative ROM was 120.8º ± 12.37º. There was no change in implant positions at the final follow-up. We found radiolucent lines in 3 knees (3.29%).

CONCLUSION

At a mean follow-up of 5.9 years, the implant-related cumulative percentage revision rate was 3.3% (2 of 91) at a mean follow-up of 5.9 years, with good clinical and functional results.

Revision total knee arthroplasty longer term outcome and comparison between infection and aseptic loosening at mean follow-up of 10 years

Background:

Although the majority of total knee arthroplasty cases have good outcome and survival, some arthroplasty eventually required revision. While early outcomes of revision knee arthroplasty are well reported, there is relatively fewer literatures reporting on the longer term outcome of revision knee arthroplasty. This study aims to review the outcome of revision knee arthroplasty for a longer term, and also make comparison between the two common indications for revision arthroplasty of infection and aseptic loosening.

Methods:

This study reviews all total knee arthroplasty revision performed at a single center over a 11 year period. Of the 48 cases found, 35 cases not lost to follow-up had a mean follow-up duration of 10.6 years (SD 2.9) for aseptic loosening, and 10.1 years (SD 2.6) for infection. Data of initial arthroplasty, revision arthroplasty, demographics, follow-up outcome were obtained, analyzed and compared.

Results:

Revision arthroplasty due to infection had more cases that required use of varus/valgus constraints (p ∼ 0.008) and extensile surgical exposure of quadriceps snip (p ∼ 0.005) compared to aseptic loosening. The survival at 10 years for this study is 91% overall (aseptic loosening 93.3%, infection 89.3%). Infection cases had significant initial improvement for range of motion (p ∼ 0.001) and use of walking aid (p ∼ 0.04) at post-operation 1 year, but no significant differences between the infection and aseptic loosening cases at 5 years and 10 years follow-up. Comparison between the two groups on other factors including initial arthroplasty, operative details, demographics, post-operative details and X-rays showed no statistically significant difference.

Total knee arthroplasty: A single centre review at 10 years of follow-up

Background:

Total knee arthroplasty is a common procedure for treatment of various non-infective arthritis. This study reviewed total knee arthroplasty cases up to 10 years of follow-up for the survival rate, reasons of revision and associated perioperative risk factors for revision.

Methods:

All cases to total knee arthroplasty performed in a single centre in the years 2007 and 2008 were reviewed. A total of 227 cases of total knee arthroplasty were performed during the 2-year period, with 156 cases followed up to 10 years. Perioperative information, follow-up information and information of possible complications were obtained.

Results:

The survival rate of total knee arthroplasty in this study is 98.2% at 5 years and 94.2% at 10 years of follow-up. The early post-operative complication rate was low, and majority of cases had improvement of function at 1 year after the operation. Early post-operative infection rate was low at 0.4%, and overall infection up to 10 years of follow-up was also low at 4.4%. Ten cases had undergone revision of arthroplasty by 10 years after operation.

Conclusion:

The survival rate of total knee replacement was high. The revision rate and infection rates were low up to 10 years of follow-up. The most common reasons of revision arthroplasty were infection and aseptic loosening. Cases which required revision arthroplasty had significantly longer operative duration compared with cases without revision at 10 years of follow-up ( p = 0.01).

Target range of motion for rehabilitation after total knee arthroplasty

Objective: Postoperative knee range of motion (ROM) is among the most important factors influencing patient satisfaction after total knee arthroplasty (TKA). The purpose of this study was to clarify the time course of improvement in knee ROM up to 12 months after TKA, including intraoperative knee ROM after implantation, and to clarify a target ROM for rehabilitation after TKA.

Patients and Methods: In total, 39 knee joints in 26 patients with osteoarthritis who underwent TKA (retaining the posterior cruciate ligament) were evaluated. Goniometry was used to measure the knee range of extension and flexion preoperatively; intraoperatively; at 1 and 2 weeks after TKA; and then at 1, 3, 6, and 12 months after TKA.

Results: The postoperative extension range gradually improved up to a maximum at 6 months after TKA; there were no significant differences in the extension range between intraoperative and 6 months after TKA, intraoperative and 12 months after TKA, or 6 and 12 months after TKA. The postoperative flexion range gradually improved, with the maximum improvement observed at 3 months after TKA; there were no significant differences in the flexion range before TKA and 3, 6, and 12 months after TKA. There were no significant differences between flexion ROM measured at 3, 6, and 12 months after TKA.

Conclusions: The changes in the knee range of extension plateaued 6 months after TKA, and those in the knee range of flexion plateaued 3 months after TKA. The target range of extension for rehabilitation from 6 months to 12 months after TKA was the intraoperative range, and the target range of flexion for rehabilitation from 3 months to 12 months after TKA was the preoperative range.