Differential knee joint loading patterns during gait for individuals with tibiofemoral and patellofemoral articular cartilage defects in the knee.

OBJECTIVE: To determine compartment-specific loading patterns during gait, quantified as joint reaction forces (JRF), of individuals with knee articular cartilage defects (ACD) compared to healthy controls (HC).

METHODS: Individuals with ACDs and HC participated. Individuals with ACDs were divided into groups according to ACD location: PF (only a patellofemoral ACD), TF (only a tibiofemoral ACD), and MIX (both PF and TF ACDs). Participants underwent three-dimensional gait analysis at self-selected speed. TF joint reaction force (TF-JRF) was calculated using inverse dynamics. PF joint reaction force (PF-JRF) was derived from estimated quadriceps force (FQUAD ) and knee flexion angle. Primary variables of interest were the PF- and TF-JRF peaks (body weight [×BW]). Related secondary variables (gait speed, quadriceps strength, knee function, activity level) were evaluated as covariates.

RESULTS: First peak PF-JRF and TF-JRF were similar in the TF and MIX groups (0.75-1.0 ×BW, P = 0.6-0.9). Both peaks were also similar in the PF and HC groups (1.1-1.3 ×BW, P = 0.7-0.8), and higher than the TF and MIX groups (P = 0.004-0.02). For the second peak PF-JRF, only the HC group was higher than the TF group (P = 0.02). The PF group walked at a similar speed as the HC group; both groups walked faster than the TF and MIX groups (P < 0.001). With gait speed and quadriceps strength as covariates, no differences were observed in JRF peaks.

CONCLUSIONS: The results suggest the presence of a TF ACD (TF and MIX groups), but not a PF ACD (PF group), may affect joint loading patterns during walking. Walking slower may be a protective gait modification to reduce load.