Second Generation Patient Specific Total Knees Demonstrate a Higher Manipulation Rate Compared with “Off-the-shelf” Implants

Abstract

Introduction. Patient specific total knee arthroplasty (TKA) theoretically
provides a more accurate fit to the native knee but may
have difficulty achieving full range of motion (ROM) post-operatively.
Post-operative ROM data were compared between patients
who underwent cemented patient-specific cruciate-retaining
(PSCR) and standard cemented posterior-stabilized (SPS) TKAs.

Methods. PSCR and SPS TKAs that were performed from January
2014 to September 2015 by the same surgeon using the same postoperative
protocols at two selected facilities were reviewed. Twoand
six-week post-operative ROM data were obtained and the
number of patients with knee flexion less than 110° was recorded.

Results. Twenty-one patients in the PSCR group and 57 patients
in the SPS group were included. The percentage of patients
with knee flexion less than 110° was similar in both groups preoperatively
(10% vs 14%, p = 0.60) and two-week post-operatively
(57% vs 68%, p = 0.35). However, at six-week post-operatively
there was significant difference (29% vs 7%, p = 0.01).

Conclusions. These results provide evidence to alert orthopaedic
surgeons when using these patient specific implants versus conventional
TKA methods. Patients whose TKA was performed using
patient specific cutting guides struggled to obtain 110° of knee
flexion. Close monitoring, aggressive physical therapy, and early
manipulation are recommended when using patient specific cutting
guides and custom total knee implants. Further evaluation in
a larger group of patients is warranted. KS J Med 2016;9(4):88-92.