Overhead arm positioning in the rehabilitation of elbow dislocations: an in vitro study

Key points

1. 01The overhead position let an elbow with both ligaments cut move almost identically to an intact elbow, especially during active extension.
2. 02Passive movement with the arm hanging down (dependent position) caused the most abnormal rotation after injury and should be avoided early on.
3. 03A neutral forearm (not turned in or out) showed the closest match to normal motion when the arm was overhead.
4. 04Findings come from 11 cadaver arms with simulated injury and simulated muscle activity, so they describe mechanics, not patient outcomes.
5. 05A cited clinical series (Schreiber et al.) of 27 patients started overhead motion at 1 week and reported no instability, supporting the lab finding.

How it was conducted

Design

In vitro biomechanical cadaveric study using a custom elbow motion simulator

Specimens

11 fresh-frozen cadaveric upper extremities, mean age 76 plus or minus 11 years, 4 male

Conditions tested

Arm in overhead, dependent, and horizontal positions; forearm pronated, neutral, or supinated; passive and simulated active extension

States compared

Intact elbow versus simulated dislocation (MCL, LCL, common flexor-pronator and extensor origins, and anterior capsule sectioned)

Outcomes

Internal-external rotation and varus-valgus angulation of the ulnohumeral joint, tracked electromagnetically; analyzed with repeated-measures ANOVA, alpha = 0.05

What they found

• During active extension overhead, elbow kinematics were not significantly affected by combined MCL-LCL injury (pronated VVA intact 8.3 plus or minus 7.0 degrees vs injured 8.8 plus or minus 6.9 degrees, P = .25).
• Overhead, passive motion with the forearm supinated increased valgus angulation after injury (+1.8 plus or minus 1.0 degrees, P = .02).
• Overhead, ligament sectioning increased external rotation in all forearm positions (pronated +1.9 plus or minus 0.1 degrees, P = .01; neutral +0.9 plus or minus 0.2 degrees, P = .03; supinated +0.1 plus or minus 0.3 degrees, P = .02).
• Overhead during active motion, pronation increased valgus angle versus neutral (+1.2 plus or minus 0.3 degrees, P = .04) and versus supination (+1.5 plus or minus 0.4 degrees, P = .03), with no difference between active and passive motion (P > .05).
• In the dependent position, passive injury increased internal rotation when pronated (-4.6 plus or minus 0.4 degrees, P = .01) and increased external rotation when neutral (+5.6 plus or minus 2.4 degrees, P = .03) and supinated (+8.7 plus or minus 1.8 degrees, P < .01).
• The overhead position increased internal rotation versus dependent with a neutral forearm (-8.5 plus or minus 2.5 degrees, P = .04) and versus horizontal with a supinated forearm (-12.7 plus or minus 2.2 degrees, P = .02).

Limitations

• This is an in vitro cadaver study, so it measures joint mechanics under simulated conditions rather than real patient recovery, pain, or function.
• Only 11 specimens were tested, with a mean age of 76 years that may not represent younger dislocation patients.
• The injury was created by surgically cutting ligaments to mimic dislocation, which may not match the variable tissue damage seen in actual injuries.
• Muscle action was simulated with applied loads, an approximation of real active rehabilitation movement.

Why it matters

For patients

If you have dislocated your elbow, your therapist may have you do early movement with your arm raised overhead because it appears to keep the joint more stable.

For clinicians

Consider early active overhead extension, ideally with the forearm neutral, for simple dislocations with combined MCL and LCL injury, and avoid passive extension in the dependent position early on.

For readers

This bench study explains the mechanical rationale for overhead rehabilitation but does not by itself prove better clinical outcomes.