Primary Arthroplasty
The Evolution of Implant Design Decreases the Incidence of Lateral Release in Primary Total Knee Arthroplasty

https://doi.org/10.1016/j.arth.2016.11.050Get rights and content

Abstract

Background

Appropriate balancing of the patellofemoral joint (PFJ) using a lateral release can help to prevent patellar instability in total knee arthroplasty (TKA). Contemporary total knee implant designs are characterized by enhanced trochlear geometry more similar to native knee anatomy to minimize instability and reduce utilization of a lateral release.

Methods

We retrospectively reviewed consecutive TKA cases from a single senior surgeon's practice with 3 successive total knee designs: the Press-Fit Condylar (PFC), the Sigma, and the ATTUNE (DePuy, Warsaw, IN). We evaluated the use of lateral release with each implant type to determine if design changes have improved patellar stability, reducing the need for lateral release. We used multivariate analysis to determine the association between implant type and lateral release, adjusting for age, sex, preoperative alignment, and bearing type.

Results

We evaluated 1991 records of primary TKAs performed from 1980-2015. As compared with the ATTUNE, the adjusted odds of lateral release were greater for patients receiving PFC implants (Odds ratio [OR] 6.35, 95% confidence interval [CI] 3.85,10.49) and Sigma implants (OR 2.02, 95% CI 1.26, 3.23). In addition, fixed bearing implants were associated with greater adjusted odds of lateral release (OR 1.80, 95% CI 1.24, 2.62).

Conclusion

We found that older knee implants were associated with higher use of lateral release, with successive designs the need for lateral release to balance the PFJ decreased. Continued design improvements to match the native knee anatomy may further improve the stability of the PFJ in future designs.

Section snippets

Methods

We retrospectively abstracted the operative notes and patient charts of all patients who underwent a primary TKA performed by a single senior surgeon between 1980 and 2015. Patients were included if they had undergone unilateral or bilateral primary TKA. We grouped implants in 3 categories: cruciate retaining, posterior sacrificing, and rotating platform (RP). Exclusion criteria were age below 18 years, the use of revision style implants for a primary TKA, and patient charts lacking essential

Sample Characteristics and Bivariate Associations

We reviewed 2547 patients' records from one single senior surgeon's operative reports and patient charts between 1982 and 2015. Two thousand sixty-five patients had primary TKAs. Seventy-four records were excluded because of missing essential clinical and surgical information. Our final study sample included 1991 primary TKAs. There were 65% women and 35% men. The mean patient age was 67.0 (SD ± 10.5) years at the time of surgery. Preoperative diagnosis was osteoarthritis in 82% followed by

Discussion

The PFJ remains an important aspect of a successfully performed TKA. If not adequately balanced or assessed, there is an increased risk for anterior knee pain, subluxation and instability, fracture, loosening of the patellar button, and lower patient satisfaction 9, 10. Revision for anterior knee pain and dysfunction has been cited by many as a common cause for revision, and historically some authors have noted up to 20% of patients having issues with instability in older designs 3, 11, 12, 13.

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    One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2016.11.050.

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