Introduction Tibial plateau fractures involve the knee joint, one of the most weight-bearing joints in the body. Studies have shown that gait asymmetries exist several years after injury. Instrumental gait analysis, generating both kinematic and kinetic data from patients with tibial plateau fractures, is uncommon. Aim To examine walking ability and knee range of motion in patients suffering intra-articular tibial plateau fractures. Method Twenty participants, eight males and 12 females, aged 44 years (range 26–60), with unilateral isolated tibial plateau fractures, were examined 12 weeks (range 7–20) after injury. The investigation consisted of passive range of motion (ROM) using a goniometer, six-minute walking test (6 MW), pain estimation using the visual analogue scale (VAS), the “Knee injury and Osteoarthritis Outcome Score” (KOOS) self-assessment questionnaire and instrumental 3-dimensional gait analysis (3DGA). 3DGA included spatiotemporal variables (speed, relative stance time, step length), kinematic variables (knee flexion, knee extension, ankle dorsiflexion) and kinetic variables (generating knee power (extension) and ankle power (plantarflexion)). A skin marker model with twenty reflective markers was used. Non-parametric tests were used for comparisons of the injured leg, the uninjured leg and a reference group. Result The participants walked more slowly compared with healthy references (p < 0.001). Stance time and step length was shorter for the injured side compared with the uninjured side (p < 0.014). Step length was shorter compared with the reference group (p = 0.001). The maximum knee extension in the single stance phase was worse in the injured side compared with the uninjured side and the reference group (p < 0.001) respectively. The maximum ankle dorsiflexion during stance phase was higher in the injured leg compared with the uninjured side and the reference group (p < 0.012). Maximum generated power in the knee was lower in the injured side compared with the uninjured side and the reference group (p < 0.001 respectively). The same was true of maximum power generated in the ankle (p < 0.023). The median KOOS value was lower in the study group (p < 0.001). ROM showed decreased flexion and extension in the knee joint and decreased dorsiflexion in the ankle joint compared with the uninjured side (p < 0.006). The average distance in the six-minute walking test was shorter in the study group (p < 0.001). Conclusion Patients who have sustained tibial plateau fractures generally display a limitation in their walking pattern 3 months after injury. These limitations are mainly related to the inability to extend the knee.