Range of extension after spontaneous recovery of knee joint contractures of various severities. Knees were surgically fixed at approximately 45° of flexion. More severe flexion contractures obtained decreased range of knee extension, irreversibly, despite proportionately long recovery durations. Data shown correspond to the angles of extension reached after the longest spontaneous recovery durations. (e.g., “week 2/8” = 2 weeks of fixation and 8 weeks of recovery).