Effects of supramalleolar osteotomies for ankle osteoarthritis on foot kinematics and lower leg muscle activation during walking.
BACKGROUND
Early stages of asymmetric ankle osteoarthritis can be treated by joint preserving supramalleolar osteotomies that surgically realign the ankle and unload degenerated cartilage. While studies have already shown pain relief and functional improvements, the effects on gait biomechanics are largely unknown. This study investigated patients' gait pattern after supramalleolar osteotomies by focusing on foot kinematics and lower leg muscle activation.


METHODS
An instrumented three-dimensional gait analysis with simultaneous electromyography of gastrocnemius medialis and lateralis, soleus, peroneus longus, and tibialis anterior muscles was performed on 12 patients with ankle osteoarthritis, seven of which were followed up 12-18months postoperatively. Additionally, seven different long-term follow-up patients (8-9years postoperatively) and 15 healthy control subjects were measured. The waveforms of the foot kinematics and muscle activation were analyzed using principal component analysis.


RESULTS
Compared to healthy controls, principal component scores that affected the sagittal range of motion of the hindfoot and hallux were lower in all patient groups, while scores that affected the timing of the peaks in the sagittal forefoot motion were mainly altered in short-term follow-up patients. Lower principal component scores in patients with ankle osteoarthritis and short-term follow-up patients resulted in a less pronounced peak activation of gastrocnemius medialis and soleus.


CONCLUSIONS
Both postoperative patient groups showed similar adaptations in their gait pattern as those observed in patients with ankle osteoarthritis. These changes are probably related to the lower ankle mobility. However, the reduced mobility seems to affect the patients' well-being less than a painful joint.
Orthopaedic Department, University Hospital, University of Basel, Switzerland; Osteoarthritis Research Center, University of Basel, Switzerland. Electronic address: corina.nueesch@usb.ch.
Corina
C
Nüesch
Orthopaedic Department, University Hospital, University of Basel, Switzerland; Osteoarthritis Research Center, University of Basel, Switzerland. Electronic address: victor.valderrabano@usb.ch.
Victor
V
Valderrabano
Biomechanics & Calorimetry Center Basel, University of Basel, Switzerland; Laboratory for Biomechanics and Biomaterials, Hannover Medical School, Germany.
Cora
C
Huber
Orthopaedic Department, University Hospital, University of Basel, Switzerland; Osteoarthritis Research Center, University of Basel, Switzerland.
Geert
G
Pagenstert
D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology* / Q000601:surgery; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D005528:Foot / Q000503:physiopathology; D005545:Forefoot, Human / Q000503:physiopathology; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010003:Osteoarthritis / Q000503:physiopathology* / Q000601:surgery; D010027:Osteotomy / Q000379:methods*; D025341:Principal Component Analysis; D016059:Range of Motion, Articular / Q000502:physiology; D016138:Walking / Q000502:physiology*
Ankle osteoarthritis; EMG; Foot kinematics; Gait analysis; Principal component analysis