PROM is an abbreviation for 'Passive Range-of-Motion', which is the range of motion your knee can achieve when someone moves it for you. [The abbreviation can also be used for 'patient-reported outcome measure' - but that is usually given as a plural - ie PROMS.]
Page updated April 2024 by Dr Sheila Strover (Clinical Editor)
What range of motion is needed for ordinary activities?
For ordinary daily activities a person needs -
- <93 degrees of knee flexion for rising from a seated position
- 106 degrees of knee flexion for shoelace tying
- 135 degrees of flexion to properly take a bath
Extension is less forgiving. Only in full extension does the lock-back mechanism work to lock the knee and support the body without any other effort.
The passive range of motion needs a helper to take the knee through the available range of motion without the patient trying to help, so that the muscles are relaxed.
Using a CPM machine for PROM
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Quote from peer-reviewed paper:
However "...the ROM the knee experiences in a CPM machine is considerably less than initially anticipated. According to our findings, a CPM motion arc of 0° to 90° may only give rise to 60° to 70° of actual knee motion."
Citation: Bible JE, Simpson AK, Biswas D, Pelker RR, Grauer JN. Actual knee motion during continuous passive motion protocols is less than expected. Clin Orthop Relat Res. 2009 Oct;467(10):2656-61. doi: 10.1007/s11999-009-0766-1. Epub 2009 Feb 27. PMID: 19247728; PMCID: PMC2745449.
Forum discussions
- Re: ruptured patellar tendon
Patient struggling to regain range of motion after patellar tendon rupture.
