Pressure algometry is an excellent tool to measure knee pain relief after a closing-wedge high tibial osteotomy

The aim of this study was to assess the utility of pressure algometry (PA) to measure pain relief in the medial part of the knee after a closing-wedge high tibial osteotomy (CWHTO).

Prospective study including 44 CWHTO. Pain relief was evaluated with the visual analogue scale (VAS) and PA, a radiological study was done and a functional assessment was carried out with the KSS preoperatively, at 6-months and at 1-year after the surgery. PA was applied to the medial and lateral part of the knee and to the infra-clavicular fossa as a control point.

The mechanical femorotibial angle was changed from 172.2° (SD2.2) to 180.6° (SD2.6) (p=0.00). KSS Knee improved from 53.4 (SD11.2) to 92.8 (SD7.3) (p=0.00), KSS Function from 69.4 (SD9.3) to 93.1 (SD8) (p=0.00). The VAS went from 6.84 (SD1.5) to 2.5 (SD2.1) (p=0.00) at the 1-year follow-up. The pressure pain threshold (PPT), measured with PA in the medial part of the knee also improved from 348.8kPa (SD159.3) to 447.1kPa (SD218.8) (p=0.01). However, the PPT in the lateral part of the knee and in the sub-clavicular fossa remained the same from the preoperative period to 6-months and 1-year, postoperatively. Neither were there any differences between the 6-month and 1-year postoperative values in terms of the different functional, radiological and pain relief obtained.

The pain relief obtained after a CWHTO in the medial part of the knee can be measured by using PA. Furthermore, the functional and pain improvement obtained at 1-year follow-up is no better than those obtained at 6-months postoperatively.