Summary

The summary of observations made during 4 years of PSI-guided lower extremity correction using an original surgery planning protocol.

Abstract

Introduction

Personalised Surgical Instruments (PSI) have received a lot of attention throughout the last decade. With the 3D-print becoming more accessible and less costly, 3D-aided surgery has become reality in many medical fields. Orthopaedic surgeons have employed 3D-printed surgical guides and simulations in treating complex fractures for several years now, but recently more attention has been brought to its usefulness in limb alignment correction which, as a procedure that in many cases offers an alternative to the early total knee replacement (TKA), has become popular with the today's society preferring to retain a more active lifestyle than in the past.

Material & Methods
Between 2018 and 2022 the total of 88 patients (35 males and 33 females; mean age: 53 years) were qualified for lower limb alignment correction. In all cases surgical treatment was complemented by intensive physical therapy programme and post-op biological treatment in the form of ultrasound guided platelet-derived growth factors injection. 17 patients diagnosed with advanced OA were recommended a simultaneous bilateral HTO and underwent the surgeries as advised.
Limb axis was evaluated pre- and post-op in long limb axis (LLA) X-Ray images. The follow-up LLA X-Ray was taken at 6 weeks post-op along with follow-up AP and LAT images. Pre-surgical planning included the LLA X-Ray to establish the optimal correction angle and CT scan for 3D joint rendering and correction simulation. The 3D-printed guides used by the authors include a tibial guide with drill and saw pre-planned slots designed to „lead“ the surgeons hand during the operation, tibial tuberosity component, and a dedicated wedge to be used to achieve planned correction and easily fix the bone using a titanium plate and screws.

Results

The total of 117 lower extremities were corrected with the correction angle ranging from 5° to 16° (mean correction angle at 10,41°).
There were no complications throughout any of the surgeries and in the recovery period. Planned correction angle was achieved with +/- 1° accuracy, while maintaining relatively short surgery time with minimum blood loss. All patents were allowed immediate post-op weight-bearing (crutches-aided) and started regular physical therapy right after discharge.
There are no major post-op complications on the record. Patients were ambulating with some degree of pain immediately after the surgery. The extent of post-op oedema/swelling was little to moderate. In all cases excellent soft tissues healing rate was observed - between 4 and 8 weeks post-op with also excellent bone healing rate - between 6 and 12 weeks. All patients reported significant improvement in their everyday functioning compared to the time before the surgery.

Conclusions

PSI-aided surgery allows for significant reduction of time and effort required for lower extremity alignment correction while maintaining high level of accuracy with decreased post-op recovery time and enhanced healing rate thanks to the pre-surgical planning significantly reducing the risk of over-/under-correction and decreasing intra-operative blood loss thus optimising treatment outcome.