Pre-operative templating for trauma hemiarthroplasty (Thompson's)

Abstract

Introduction: Surgical complications may be avoided by preoperative templating in trauma hemiarthroplasty.

Materials and methods: Digital templates for the Stryker™ range of Thompson's prostheses were created and fifty trauma patients that had undergone cemented hemiarthroplasty were retrospectively templated by 2 blinded surgeons.

Results: Templating for prosthesis size was highly accurate with excellent Inter and intra-observer reproducibility. Sensitivity for identifying femoral canals too narrow for a Thompsons was 100%.

Conclusions: Templating is a valuable tool and should be standard practice in trauma. We have demonstrated that it is possible to generate custom templates to allow accurate templating.

Keywords: Hemiarthroplasty; Hip fracture; Neck of femur; Templating; Thompsons.

Fig. 1

Left image depicts the 57 mm prosthesis embedded into the block. Right image demonstrates the 38 mm prosthesis placed into the imprint left by the largest prosthesis, confirming stem geometry remains consistent across the range of head sizes.

Fig. 2

Templating example, the widest bony diameter measures 46 mm and the joint space is 3 mm. A 49 mm head template is applied and overlaps the native femoral head concentrically.

Fig. 3

To determine if the femoral canal is too narrow, the template is aligned with the shaft at the level of neck osteotomy where correct leg length is restored. Here there is ample space for the Thompson's.

Fig. 4

Templated and post-operative plain films of same case demonstrating how neck cut should be adjusted in coxa valga otherwise limb length discrepancy can result.