2023 ISAKOS Biennial Congress ePoster
Radiographic Tibial Tunnel Assessment After Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts and Biocomposite Screws: A Prospective Study with 10-Year Follow-up
Sadesh Balasingam, MD, Gothenburg SWEDEN
Ioannis Karikis SWEDEN
Lars Christensen, MD, Lidköping SWEDEN
Mattias Ahldén, MD, Gothenburg SWEDEN
Ninni Sernert, PhD, RPT, Trollhättan SWEDEN
Jüri T. Kartus, MD, PhD, Trollhättan SWEDEN
NU Hospital Group, Trollhättan, Västa Götaland, SWEDEN
FDA Status Cleared
Summary
The majority of patients having undergone ACL reconstruction using biocomposite screws containing ß-TCP as tibial graft fixation had reduced tunnel width on one or both radiographic views 10-years post surgery.
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Abstract
Background
Biocomposite screws have gained increased attention due to reportedly providing desirable graft fixation in anterior cruciate ligament reconstruction (ACLR), whilst also simplifying any subsequent imaging and surgery in comparison to metallic screws. However, one purported complication of biocomposite screws is paradoxical tunnel widening. Previous studies on screws containing ß-tricalcium phosphate (ß-TCP) have only reported outcomes at short- and medium-term follow-up.
The aim of this study was to radiographically assess the tibial tunnel over 10 years after anterior cruciate ligament (ACL) reconstruction using hamstring tendon autografts and biocomposite interference screws containing ß-tricalcium phosphate (ß-TCP) in both anatomic single-bundle (SB) and double-bundle (DB) methods.
Methods
Fifty patients received anatomic SB ACLR and 53 patients received DB ACLR, all with metal interference screws in the femur and biocomposite interference screws in the tibia made of self-reinforced poly-levo (96%)/dextro (4%)-lactide/ß-TCP [SR-PL(96)/D(4)LA/ß-TCP](77% PLDLA and 23% ß-TCP) . Standardized digital radiographs with weight-bearing anteroposterior and lateral views of the index knee were taken in the early postoperative period as well as at 2-, 5-and 10-years postoperatively; computer tomography (CT) imaging was also performed at 10-year follow-up. Of the initial 105 patients, 26 (51%) of the SB group and 35 (66%) of the DB group completed radiographic follow-up at all time intervals. Subjective and objective clinical assessments were recorded pre-operatively and at the 10-year follow-up.
Results
The mean follow-up period was 122 months. In 32 of an available 43 radiographs (74%) of SB patients the width of the tibial tunnel had decreased at 10 years compared with the early postoperative period. The mean tibial tunnel volume as measured on CT was 2.04 cm3 (± 0.85 cm3).
Tibial PL tunnel width had decreased in 31 of an available 56 radiographs (55%); the corresponding was found in 41 of 62 (66%) radiographs for the tibial AM tunnel in the DB patients at 10-year follow-up. The mean AM tunnel volume as measured on CT was 2.04 cm3 (±1.92 cm3) and the mean PL tunnel volume was 1.38 cm3 (±0.54 cm3).
There was no correlation between tunnel widths and the KT-1000 assessments, though there was a statistically significant correlation between SB tibial tunnel volume on CT imaging and KT-1000 anterior 134N side to side difference (r= 0.46, p = 0.038).
Conclusions
The majority of patients’ tibial tunnels had decreased on 1 or both radiographic views at 10-year follow-up compared to the early postoperative period after ACL reconstruction using biocomposite interference screws containing ß-tricalcium phosphate. However, the tunnels were still visible in the majority of patients at 10 years, both on standard radiographs and CT imaging.