Osteoarthritis of the knee joint associated with a walking pattern classified as crouch gait in adolescents and adults with cerebral palsy

The aim of this prospective study of a continuous cohort was to investigate anatomical and functional disorders, as well as their combination with manifestations of pathological changes in the articular cartilage of the knee joint in patients with cerebral palsy and a gait pattern classified as crouch gait. Materials and methods The study cohort consisted of 24 patients (20 men and 4 women) with cerebral palsy who had completed natural long bone growth (ages 16 to 42 years). Clinical, X-ray data, results of magnetic resonance imaging, computer analysis of gait, as well as visual assessment of articular cartilage according to Outerbridge were studied in two groups of patients: with natural development of crouch gait (group 1) and with iatrogenic crouch gait (group 2). Results According to the KSS questionnaire, in group 1, four patients (28.6 %) had a satisfactory function of the knee joint, and 10 patients (71.4 %) had poor function. Pain in the knee joint was reported by 12 patients (85.7 %). In the second group, two patients (20 %) had a satisfactory function, and the remaining eight (80 %) a poor one; pain syndrome was reported in 8 cases (80 %). Local articular cartilage defects were found in 6 out of 14 examined patients (42.9 %) in group 1 and in 6 out of 10 examined patients (60 %) in group 2. More pronounced efforts and high energy intensity of walking were found in patients with iatrogenic crouch gait: a more significant moment of force acting on flexion in the knee joint at initial contact, as well as a more pronounced pelvic tilt, combined with significant energy requirements to overcome the maximum flexion and extension moments in the hip joints. For the group of iatrogenic crouch gait, additional factors were found that predispose to pain and arthrosis of the knee joint: stiff knee gait (“frozen knee”), the shift of the generated energy towards the knee and hip joints. Conclusions The crouch gait pattern is heterogeneous in terms of the mechanisms, radiological features of foot deformities, and parameters of computer analysis of gait. An increase in power generation at the level of the hip joints is a common phenomenon in crouch gait, but with the natural development of this gait pattern, a large degree of power generation is also preserved at the level of the ankle joint, while in iatrogenic crouch gait, a decrease in the power generation of the ankle joint and, as a result, the developed increased power at the level of the knee joint contributes to the progression of arthritic degenerative changes. Damage to the articular surfaces of the knee joint is a manifestation of early arthritic changes and requires correction along with the standard elements of surgical intervention in the crouch gait pattern.