A recent clinical trial has shed light on the surgical precision of High Tibial Osteotomy (HTO) when using a novel Patient-Specific Instrument (PSI). The study addresses the ongoing challenge of achieving accurate realignment in HTO, a joint-preserving procedure for patients with knee osteoarthritis and malalignment. It evaluates whether a custom-designed PSI can offer a tangible advantage over traditional freehand techniques, particularly in the hands of experienced surgeons.
The Challenge of Surgical Precision in HTO
Medial opening-wedge HTO is a widely accepted treatment, but its success hinges on achieving precise realignment of the tibia. Conventional techniques, even when performed by expert surgeons, can suffer from a lack of accuracy. Minor deviations from the planned correction can lead to unpredictable outcomes, including altered load transfer and a higher risk of complications. This has led to the development of computer-aided technologies, such as navigation and Patient-Specific Instruments, to improve surgical reliability.
The core of this clinical trial was to compare a novel PSI with the standard freehand method in a rigorous, double-blind, randomised controlled setting. The primary objective was to assess if using the custom cutting guide could improve the radiological accuracy of the osteotomy. A key focus was on the mean deviation from the planned correction in the coronal, sagittal, and axial planes.
Study Methodology and Key Findings
The trial involved 36 patients with symptomatic medial compartment knee osteoarthritis. They were randomly allocated to undergo HTO with either the custom 3D-printed PSI or the traditional freehand method. The study aimed to mitigate potential biases by blinding both patients and outcome assessors to the treatment group.
While a recent cadaveric study demonstrated that the PSI technique resulted in significantly less deviation from the planned wedge size and reduced radiation exposure for staff, the clinical trial found no statistically significant difference in surgical accuracy between the two groups when performed by expert surgeons. The mean difference in the postoperative and planned weight-bearing line was comparable for both the PSI and conventional cohorts. This suggests that while PSI technology has the potential to enhance precision, its benefit in the hands of highly experienced surgeons may not be as pronounced as with less experienced operators.
Broader Context of Patient-Specific Instrumentation
The use of patient-specific guides and plates is part of a broader trend towards personalised orthopaedic treatment. These technologies are designed to make complex procedures more predictable and reproducible, potentially shortening operative time and reducing the learning curve for surgeons. However, this clinical trial highlights an important point: for a procedure that is already performed with a high degree of skill, the additional benefits of a custom guide may be limited.
The study, while not demonstrating a statistically significant improvement in accuracy for expert surgeons, adds to the body of evidence surrounding this evolving technology. The continued development of personalized orthopaedic tools holds great promise for the future of surgery, particularly in complex cases or for surgeons who are earlier in their learning curve.
Professor Wilson’s Comments
“This was a very interesting study that we conducted looking at patient-specific instrumentation (PSI) right at the beginning of its journey. It was a privilege to be part of this important collaboration with Imperial College. What proved most interesting, however, was that we often had to abandon the PSI guides and revert to the conventional techniques we had developed ourselves.
The key takeaway was that PSI serves as a valuable training tool for lower-volume surgeons who benefit from guided assistance in the early stages of their learning curve. However, for more straightforward osteotomy procedures, most experienced surgeons performing higher volumes tend to abandon the guides and operate freehand. Where PSI truly comes into its own is in complex osteotomy surgery involving multiplanar deformities, where it can be extremely helpful.”
To delve into the complete findings, methodology, and analysis, the full research paper is available for your review.
Sources used in report overview:
- https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3280140
- https://www.google.com/search?q=https://www.researchgate.net/publication/33550239_Patient-specific_instrumentation_PSI_Referencing_High_Tibial_Osteotomy_Technological_Transfer_and_Education_Protocol_for_a_double-blind_randomised_controlled_trial_PROTECTED_HTO_Trial
- https://www.researchgate.net/publication/366720115_Is_Patient-Specific_Instrumentation_Accurate_and_Necessary_for_Open-Wedge_High_Tibial_Osteotomy_A_Meta-Analysis
