MSK-10 · Knee Anatomy, ACL, PCL, and Ligaments

Knee Anatomy, ACL, PCL, and Ligaments. Part of the Musculoskeletal series of the Reflex PM&R Board Review podcast. Audio corrections: (1) In the audio: Climbing stairs dictates a hard requirement of 90 degrees of flexion. — Correct: Stair climbing needs about 100 degrees. That is the prescriptive requirement, the mean plus two standard deviations, from the original activity-of-daily-living goniometry, whose measured mean on ascent was in the low 80s; modern gait-laboratory means run roughly 85 to 95. Ninety degrees is the post-arthroplasty benchmark, not the stair-climbing requirement. (2) In the audio: standing back up from that standard chair requires 105 degrees — Correct: Rising from a standard chair needs about 90 to 95 degrees, the same as sitting into it. The 105 degree figure is a misattribution: the source study reports 106 degrees for tying a shoe and one sit-and-rise cycle at 93 degrees, and no study separates sitting from rising. A low chair pushes toward 110 to 120. The written chapter is correct. Full correction register: https://www.reflexpmr.com/errata. The full companion chapter and a linked board-style Q-bank set for this topic are at https://www.reflexpmr.com/read/MSK-10.