New method to estimate femoral head size from the trochanteric length of the femur

Abstract

Introduction:

Preoperative planning is an important step before any joint replacement surgery. In developing countries standardised radiographs and planning tools might not be available but nevertheless hemiarthroplasties are performed in certain trauma cases. An equation should be devised to allow a preoperative estimation of the expected femoral head size dimensions in those situations.

Materials and methods:

35 lower limbs of human cadavers were studied. The estimated femoral head (EFH) size of each femur was obtained by measuring the trochanteric length (TL) (in cm) and using the equation ‘EFH = 16 + (0.7 × TL)’. The hip joint was dissected, and the actual size of the femoral head (AFH) was measured on the specimen.

Results:

There was a correlation between the EFH and AFH (p = 0.0001). Accepting a range of ±3 mm the femoral head size was predicted correctly in 31 hips (89%), for ±4 mm in 33 hips (94%) and for ±5 mm in 35 hips (100%), respectively.

Conclusions:

A simple tape measurement and the equation Femoral head size = {16 + (0.7 × Trochanteric Length)} ±5 mm gives a rather reliable guess for the expected femoral head size. It might be useful as pre-operative planning tool if no standardised radiographs are available.

Keywords

Acetabular cup femoral head femur greater trochanter hemiarthroplasty sizing total hip arthroplasty total hip replacement

Get full access to this article

View all access options for this article.

References

Ugbeye

Dim

Obideyi

OF.

Profile of fracture neck of femur in a Nigerian regional hospital. Niger J Orthop Trauma 2017; 16: 38–43.

Conn

Clarke

Hallett

JP.

A simple guide to determine the magnification of radiographs and to improve the accuracy of preoperative templating. J Bone Joint Surg Br 2002; 84: 269–272.

Wimsey

Pickard

Shaw

Accurate scaling of digital radiographs of the pelvis. A prospective trial of two methods. J Bone Joint Surg Br 2006; 88: 1508–1512.

Heep

Löchteken

, et al. A simple and convenient method guide to determine the magnification of digital X-rays for preoperative planning in total hip arthroplasty. Orthop Rev (Pavia) 2012; 4: e12.

Crosswell

Akehurst

Ramiah

, et al. Preoperative sizing of hip hemiarthroplasties to accurately estimate head size from non- standardised pelvic radiographs: can it be done? Injury 2019; 50: 2030–2033.

Hornová

Růžička

Hrubina

, et al. Magnification of digital hip radiographs differs between clinical workplaces. PLoS One 2017; 12: e0188743.

Akinmokun

Ibeabuchi

Akinsulire

, et al. Estimation of femoral head size from palpable bony prominences of the femur. West Afr J Med 2020; 37:173–177.

Ben Lulu

Rubin

Krasnyansky

, et al. Measuring the femoral head size–an additional real-time intraoperative monitoring tool for the accuracy of the preoperative process and implant selection. J Arthroplasty 2015; 30: 2201–2203.