Maximum Medical Improvement (MMI) — Complete Guide

Maximum Medical Improvement (MMI) is the point at which a treating physician determines that your work-related injury has healed as much as it is expected to heal, or has reached a stable and stationary condition. It does not necessarily mean you are fully healed or without symptoms — it means further significant improvement is not reasonably expected with continued treatment.

MMI is a critical milestone in any workers' comp claim because it triggers the evaluation of permanent disability. Once MMI is reached, your treating physician or an independent medical evaluator assigns an impairment rating that is used to calculate permanent disability benefits.

MMI timing varies significantly by injury type and severity. Simple soft tissue injuries may reach MMI in 3–6 months. Surgeries typically result in MMI 6–18 months post-operatively. Complex cases involving spinal cord injury, TBI, or multiple surgeries may not reach MMI for 2–5 years.

In most states, if MMI has not been reached within 104 weeks (2 years) of injury, temporary total disability benefits are terminated and the claim moves to a permanent disability evaluation regardless of whether the treating physician has declared MMI.

MMI triggers the impairment rating process. Your treating physician will typically assign a whole person impairment rating under the applicable guide (AMA Guides in most states, California PDRS, or the state's own schedule). This rating is used to calculate permanent disability benefits.

Before MMI, you should not accept a settlement that includes future medical benefits unless your condition is genuinely stable and you do not expect to need future treatment. Once you settle and release future medical, you are responsible for any future treatment costs.