Leg length discrepancy (LLD) can adversely affect functional outcome and patient satisfaction after total hip arthroplasty. We describe a novel intraoperative technique for femoral component insertion.

We aimed to determine if this technique resulted in the desired femoral placement, as templated, and if this was associated with a reduced LLD.

A series of fifty consecutive primary total hip replacements were studied. Preoperative digital templating was performed on standardised PA radiographs of the hips by the senior surgeon. The preoperative LLD was calculated and the distance from the superior tip of the greater trochanter to the predicted shoulder of the stem was calculated (GT-S). Intraoperatively, this length was marked on the rasp handle and the stem inserted to the predetermined level by the surgeon. This level corresponded to the tip of the greater trochanter and formed a continuous line to the mark on the rasp handle. Three independent blinded observers measured the GT-S on the postoperative radiographs. We assessed the relationship between the senior author's GT-S (preoperative) and the observers' GT-S (postoperative) using a Person correlation. The observers also measured the preoperative and postoperative LLD, and the inter-observer variability was calculated as the intra-class correlation coefficient.

There was a strong correlation of preoperative and postoperative GT-S (R=0.87), suggesting that the stem was inserted as planned. The mean preoperative and postoperative LLD were −4.3 mm (−21.4–4) and −0.9 mm (−9.8–8.6), respectively (p<0.001).

This technique consistently minimised LLD in this series. This technique is quick, non-invasive and does not require supplementary equipment.