The Effect of Two Cooling Modalities on Skin and Achilles Tendon Temperature

Does knee joint cooling change in vivo patellar tendon mechanical properties?

“…Although the extrapolation of changes in skin temperature to those that occur at the depth of the patellar tendon is complicated, it is worth noting that the patellar tendon lies close to the skin surface (~5 mm depth in most of our subjects), has a limited blood supply (Józsa and Kannus 1997 ) and is not insulated by highly perfused organs, such as skeletal muscles. Considering the significant decrease in skin temperature, it is plausible to assume that our cooling intervention elicited a drop in tendon temperature that is of greater dimension as that reported for muscle and joint in the studies by Dewhurst et al ( 2010a ) and Warren et al ( 2004 ), and similar to that reported for the Achilles tendon by Selkow et al ( 2014 ). As a predominantly collagenous tissue, tendon is also known to be very sensitive to changes in temperature (Chan et al 1998 ; Ciccone et al 2006 ; Huang et al 2009 ; Wang et al 2005 ), so we are confident that our cooling protocol elicited a strong enough stimulus to alter its mechanical properties.…”

“…Studying collagenous material obtained from rat Achilles tendons, the authors found the Young’s modulus of collagen fibrils to be higher by ~14 % at 20 °C as compared to 40 °C (Gevorkian et al 2009 ). If we assume that our cooling intervention elicited changes in patellar tendon temperature that are of comparable dimension as those reported by Selkow et al ( 2014 ) for the Achilles tendon (i.e., a decrease from ~29 to ~17 °C), and if we further take the methodological differences between our study and that of Gevorkian et al ( 2009 ) into account (in vivo vs. in vitro, tendon force estimation vs. direct force measurement, etc. ), it is plausible to assume that our findings represent the in vivo equivalence of Gevorkian’s results.…”

“…In another study, Warren et al ( 2004 ) also used ice bags for 30 min to decrease knee intraarticular temperature by 3.3 °C (at the suprapatellar pouch), with a concomitant skin temperature decrease of 21 °C. While no studies exist to directly assess the effects of knee joint cooling on patellar tendon temperature, Selkow et al ( 2014 ) reported that 20 min of ice bag cooling reduced the Achilles tendon’s internal temperature from 29.3 to 16.7 °C. Of note, skin temperature values reported in this study (27.7 and 7.1 °C) were very similar to those measured here at equivalent points of time (26.1 °C prior to cooling vs. 9.3 °C after ice application).…”