Mapping of skin surface sensitivity and skin surface temperature at the knee over a re-warming period following cryotherapy

Abstract

Background
Current literature proposes proprioceptive changes following cryotherapy applications due to changes in neurodynamic feedback from receptors altering knee joint position sense. However, minimal literature exists on the effect on skin surface sensitivity (SSS) which may be a contributing factor. This study investigated the effects of cryotherapy on knee SSS and temperature (Tsk) using monofilaments and thermal imaging in males and females.

Methods
SSS in 19 healthy participants mapped using a photographic knee pain map (PKPM), on the non-dominant knee following a 20-minute cryotherapy exposure used an Aesthesio Precision Tactile Sensory Evaluator (DanMic Global, USA) for measurement. Thermal imaging using a non-invasive infrared camera (ThermoVision A40M, Flir Systems, Danderyd, Sweden) measured Tsk. Data were collected pre, immediately post and at five-minute intervals up to 20-minutes.

Results
Statistical significant decreases in SSS are reported for superior medial section of the PKPM comparing baseline to immediately post intervention (P=0.04), and to 20-minutes post (P=0.04), and between pre to immediately post (P=0.02) and 5-minutes post (P=0.01) in the female participants only. Male only showed significant decrease in SSS between pre and immediately post intervention for the medial patella section (P=0.02).

Conclusion
Crushed ice application significantly reduces SSS around the medial aspect of the knee immediately post removal and with males and females showing different levels of response. SSS over the medial aspect of the knee had not returned to baseline 20-minutes post cooling. Therapists should be conscious of changes in SSS that may impede return to play following cooling due to feedback mechanisms which may affect joint position sense.