Cadaveric study using 20 fresh frozen fingers testing four published non-invasive clinical maneuvers for central slip integrity across two simulated injury patterns: isolated central slip division (pre-boutonnière) and central slip plus triangular ligament plus oblique fiber division (passively correctable boutonnière).
When you examine a swollen finger after a PIP hyperflexion or dislocation injury, use the Elson test — flex the PIP to 90° over a table edge and ask the patient to extend against resistance; abnormal DIP rigidity (rather than expected laxity) confirms central slip rupture even before boutonnière deformity develops.
All other bedside tests should be performed with the PIP starting in flexion, not extension, to eliminate lateral band substitution that will mask the injury.
Cadaveric study using 20 fresh frozen fingers testing four published non-invasive clinical maneuvers for central slip integrity across two simulated injury patterns: isolated central slip division (pre-boutonnière) and central slip plus triangular ligament plus oblique fiber division (passively correctable boutonnière).
When you examine a swollen finger after a PIP hyperflexion or dislocation injury, use the Elson test — flex the PIP to 90° over a table edge and ask the patient to extend against resistance; abnormal DIP rigidity (rather than expected laxity) confirms central slip rupture even before boutonnière deformity develops.
All other bedside tests should be performed with the PIP starting in flexion, not extension, to eliminate lateral band substitution that will mask the injury.