Functional performance with a single-radius femoral design total knee arthroplasty.
BACKGROUND
Better muscular recovery of the extensor mechanism after TKA is claimed by femoral designs based on a sagittal single radius.


OBJECTIVE
We aimed to compare postoperative knee performance through the Knee Society scores, flexor and extensor muscle function, stability, and gait of a series of patients receiving a posterior stabilized, cemented TKA, with a single-radius femoral design.


METHODS
We compared a series of patients treated with a single-radius femoral design TKA to a simultaneous series of patients receiving a multiradius femoral design. Both groups were similar in demographics and preoperative Knee Society scores. The clinical pathways were identical. Outcome assessment included Knee Society scores, isokinetic assessment, stabilometry, and gait cycle analysis.


RESULTS
We observed higher functional Knee Society scores (86.6 +/- 1.89 versus 80.3 +/- 1.90), fewer physiotherapy sessions (19.9 +/- 4.65 versus 22.2 +/- 3.34), and less time with two crutches (3.5 +/- 1.2 versus 5.2 +/- 1.04 weeks) for patients receiving the single-radius design. Isokinetic evaluation showed decreased flexion peak torque (40.3 +/- 7.9 versus 48.7 +/- 9.6), increased extension peak torque (77.2 +/- 16.1 versus 69.1 +/- 14.4), and lower flexor/extensor ratio (0.5 +/- 0.08 versus 0.7 +/- 0.1) in patients with the single-radius design. Stabilometry showing less relative oscillation, and gait cycle indirectly confirmed better support in the limb with the single-radius design.


CONCLUSIONS
The studied single-radius femoral design showed better functional short-term outcome and better extensor performance.


METHODS
Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Gómez-Barrena
Enrique
E
Department of Orthopaedic Surgery, Fundación Jiménez Díaz Hospital, Universidad Autónoma de Madrid, Avda Reyes Católicos 2, Madrid 28040, Spain. enrique.gomezbarrena@uam.es
Fernandez-García
Carmelo
C
Fernandez-Bravo
Almudena
A
Cutillas-Ruiz
Raquel
R
Bermejo-Fernandez
Gloria
G
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D005684:Gait / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery*; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D020127:Recovery of Function / Q000502:physiology; D012189:Retrospective Studies; D016896:Treatment Outcome