INTRAOPERATIVE ASSESSMENT OF CORONAL ALIGNMENT: A NOVEL, LOW-COST TECHNICAL TRICK

Introduction

Intraoperative assessment of coronal alignment is important when performing corrective osteotomies around the knee and ankle, limb lengthening and trauma surgery. The Joint Angle Tool (JAT) provides surgeons with information about the anatomic and mechanical axes intraoperatively based on true anteroposterior radiographs.

Aim: Presentation of the JAT, a low-cost goniometer for intraoperative assessment of the lower limb alignment.

Materials and Methods

The JAT consists of pre-printed joint orientation angles of the anatomic and mechanical axis including normal variations on a plastic sheet. It is placed on the screen of the image intensifier after obtaining a true anterior-posterior image. The pre-printed joint orientation angles can intraoperatively assist the surgeons in achieving the pre-planned axis correction. Here, its feasibility is demonstrated in four cases.

Results

Here, we present the intraoperative use of JAT in four cases:

1. 77 mm femoral bone transport due to non-union utilizing a bone transport nail,

2. distal femoral osteotomy correcting coronal and torsional malalignment using a retrograde intramedullary trauma nail,

3. proximal / high tibial open wedge osteotomy with an intramedullary implant correcting varus malalignment in a hypophosphatemic rickets patient, and

4. a supramalleolar, closing wedge osteotomy realigning the anatomic axis with a plate and screws.

Conclusions

The JAT is a modified goniometer which allows intraoperative assessment of the mechanical and anatomic axis. JAT is applicable throughout the entire surgical procedure irrespective of the method of internal fixation and may provide additional reassurance of correct alignment.

The JAT consists of a plastic sheet with printed joint orientation angles and their normal variation. JAT is freely available from profeedback.dk/JAT/JAT.pdf for use and modification according to Creative Commons license (CC BY-SA 4.0).