Summary

Uniplanar and multiplanar tibial tubercle osteotomy (TTO) using the Multi-Directional Tibial Tubercle Transfer (MD3TTM) surgical system demonstrated favorable subjective and radiographic outcomes and low complication rate at minimum 2 year follow-up.

Abstract

Introduction

Tibial tubercle osteotomy (TTO) is a valuable tool for addressing pathological compressive forces, malalignment, chondral defects, arthritis, and instability in the patellofemoral joint. It yields consistent clinical outcomes when performed by skilled surgeons. However, it is a technically demanding procedure with a steep learning curve. Recent advances in surgical technology provide the opportunity to improve precision, modularity, reproducibility, and efficiency as well as to reduce complications associated with TTO. This study aims to describe the early safety and efficacy of TTO performed with the novel Multi-Directional Tibial Tubercle Transfer (MD3TTM) surgical system. We hypothesize that use of this novel system will result in safe and effective single and multiplane alignment correction in this challenging patient population.

Methods

This study includes 42 consecutive TTOs performed by a single board certified and fellowship trained provider at one institution between October 2019 and August 2022. Patients with less than two years’ follow up at the time of data analysis were excluded. All patients met clinical criteria for TTO. Relevant data from each TTO was recorded in the patient’s electronic medical record (EMR). Subsequently, all EMRs were reviewed for demographic and surgical data, including participant age, sex, athletic history, prior patellofemoral injury, conservative treatment, previous surgery, TTO type performed, concomitant procedures, and post-operative complications. Relevant clinical data were summarized and results were analyzed statistically. Patient-reported outcome measures (PROMs) were collected and analyzed using Wilcoxon Signed-Rank tests and Mann-Whitney tests.

Results

Forty-two knees in a total of 39 patients were included. Three patients underwent bilateral surgery. The average age at time of surgery was 29 years, ranging from 16 to 69 years. The minimum follow-up time was two years, with a mean follow-up time of 39 months. Patients’ activity levels prior to surgery included recreational sports (n=21), no sports (n=13), high school sports (n=4), college sports (n=3), and professional sports (n=1). Half of the cohort (n=21) had a history of at least one patellar dislocation while 29% (n=12) had a history of at least one subluxation. 32 patients (76%) failed prior surgical treatment. TTO surgeries included anteriorization (n=5), anteromedialization (AMZ) (n=22), medialization and distalization (n=3), AMZ + distalization (n=9), and AMZ + proximalization (n=3). All patients had at least one concomitant soft tissue or cartilage procedure. 67% of patients underwent soft tissue balancing (i.e. MPFL reconstruction, lateral retinacular lengthening) and 52% underwent cartilage restoration. Among the soft tissue balancing procedures, medial patellofemoral ligament reconstruction was the most frequent (n=23, 55%), followed by lateral retinaculum lengthening (n=5, 12%). The most common cartilage procedure was matrix-induced autologous chondrocyte implantation (n=13, 31%), followed by osteochondral allograft transplantation (n=9, 21%). There were statistically significant improvements in patient-reported Knee SANE, KOOS Symptom, KOOS Sport and Recreation and KOOS QOL measures with p < 0.05. In total, a majority, 86% (n=36) of cases had no adverse outcomes, 12% (n=5) had one adverse outcome, and 2% (n=1) had three adverse outcomes. Within the study period, there were no re-operations for fracture or non-union. There were no cases of malunion. No patients required revision TTO or developed venous thromboembolism. There were five cases (12%) of superficial wound erythema that resolved with oral antibiotics, and one case (2%) of hardware removal performed during surgical lysis of adhesions at seven months post-op.

Conclusion

Uniplanar and multiplanar TTO corrections using a novel TTO system demonstrated subjective and objective patient improvement and an excellent safety profile with a low incidence of complication at minimum two-year follow-up. This technique offers the advantages of independent correction in osteotomy plane, providing enhanced modularity, precision, and reproducibility compared to traditional techniques.