Likelihood of Scapholunate Ligament Injury from Pushups Without Trauma
The likelihood of scapholunate ligament injury from pushups without trauma is extremely low in individuals with normal wrist anatomy, though pushups can potentially aggravate pre-existing scapholunate ligament damage. 1
Biomechanical Considerations
- Pushup position significantly affects scapholunate ligament stress, with neutral wrist position (knuckle pushups) creating greater gap distances between scaphoid and lunate compared to extended wrist position in wrists with pre-existing scapholunate interosseous ligament (SLIL) damage 1
- Extended wrist pushups cause significantly greater peak pressure in the radioscaphoid fossa but not in the radiolunate fossa, which may explain why degenerative arthritis typically develops first in the radioscaphoid fossa 2
- In cadaveric studies of wrists with pre-existing SLIL damage, the scaphoid extended 70.1° and the lunate extended 28.6° when the wrist was extended 90° compared to neutral position 1
Diagnostic Considerations for Suspected Injury
- Initial evaluation should include conventional radiographs with careful attention to positioning to assess for carpal malalignment 3
- In low-grade injuries, radiographs are usually normal, but scapholunate diastasis >4 mm and dorsal tilt of the lunate >10° suggests dorsal intercalated segmental instability 3
- CT arthrography has the highest sensitivity (nearly 100%), specificity, and accuracy for detecting scapholunate ligament tears 3, 4
- MRI (especially 3T) is commonly used with reported sensitivities of 65-89% for scapholunate ligament tears 3, 4
- High-frequency ultrasound with dynamic "clenched fist" maneuvers can be useful with sensitivity of 46-100% and specificity of 92-100% for tears of the dorsal band 3, 5
Risk Factors and Etiology
- Bilateral scapholunate widening may occur without trauma in some individuals, suggesting a potential non-traumatic etiology in certain cases 6
- Patients with bilateral wide scapholunate gaps without signs of carpal instability or osteoarthritis tend to be younger, suggesting progression with age 6
- Four types of scapholunate ligament injuries have been identified: lateral avulsion from the scaphoid (42%), medial avulsion from the lunate (16%), mid-substance rupture (20%), and partial rupture plus elongation (22%) 7
Clinical Implications
- Pushups in extension may be less detrimental than neutral position pushups for individuals with pre-existing SLIL damage 1
- Untreated scapholunate ligament injuries can lead to carpal instability and degenerative arthritis with subsequent loss of function and disability 8
- Bilateral scapholunate widening without trauma may progress to carpal instability and scapholunate advanced collapse with advancing age 6
Practical Recommendations
- For individuals with suspected or confirmed scapholunate ligament injury, extended wrist pushups may place less stress on the ligament than neutral position pushups 1, 2
- Individuals with wrist pain during pushups should be evaluated with appropriate imaging, starting with conventional radiographs and progressing to more advanced techniques like CT arthrography or MRI if needed 3, 4
- In patients with pre-existing scapholunate ligament damage, pushup modifications or alternative exercises may be necessary to avoid exacerbating the condition 1, 2