Patellar tendon shortening surgery restores the knee extensor mechanism in flexed knee gait in children with cerebral palsy

Henrike Greaves; David Wright; Antonio Eleuteri; Elizabeth Ray; Ornella Pinzone; Alfie Bass; Roger Walton; Gabor Barton

doi:10.1016/j.jos.2024.01.004

Patellar tendon shortening surgery restores the knee extensor mechanism in flexed knee gait in children with cerebral palsy

J Orthop Sci. 2024 Jan 23:S0949-2658(24)00005-8. doi: 10.1016/j.jos.2024.01.004. Online ahead of print.

Authors

Henrike Greaves¹, David Wright², Antonio Eleuteri³, Elizabeth Ray², Ornella Pinzone², Alfie Bass², Roger Walton², Gabor Barton⁴

Affiliations

¹ Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK; Liverpool John Moores University, Liverpool, UK. Electronic address: Henrike.Greaves@alderhey.nhs.uk.
² Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK.
³ Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK.
⁴ Liverpool John Moores University, Liverpool, UK.

PMID: 38262799
DOI: 10.1016/j.jos.2024.01.004

Abstract

Background: This study evaluated a patellar tendon shortening (PTS) surgical procedure that uses an overlapping repair combined with an additional Tycron non-absorbable suture to support the shortening in children with Cerebral Palsy (CP). This study aimed to outline this surgical technique and to evaluate its effectiveness in restoring the knee extensor mechanism.

Methods: The sagittal plane lower limb kinematics, peak knee extensor moment, gait deviation index (GDI), localised movement deviation profile (MDP), temporospatial parameters, passive knee extension ROM, quadriceps lag, and knee extensor strength were calculated pre- and postoperatively. To determine significant differences a robust linear regression model with high breakdown point and high efficiency was fitted to the data.

Results: In this retrospective cohort study, a total of 41 patients with CP who were treated with unilateral or bilateral PTS in isolation or as part of single event multilevel surgery (SEMLS), with a mean age of 11.1 years were included. The knee extension angle improved at initial contact (p < 0.0001), and during stance phase (p < 0.0001). The peak internal knee extensor moment decreased during early (p = 0.0014) and late stance phase (p < 0.0001). The quadriceps lag decreased (p < 0.0001) and knee extensor strength increased (p < 0.0001). The GDI improved (p < 0.0001), as well as the localised MDP for sagittal angles (p < 0.0001) and moments (p = 0.0001). Walking speed (p = 1.0) remained unchanged, but the cadence decreased (p = 0.024) and step length increased (p = 0.0001).

Conclusions: The knee extension angle and moment during stance phase improved significantly. The children with CP in this study showed improvements in knee extensor strength and quadriceps lag. Thereby it can be concluded that the PTS procedure was able to restore the knee extensor mechanism effectively.

Keywords: Cerebral palsy; Crouch gait; Flexed knee gait; Gait analysis; Patella tendon shortening.