This was a prospective consecutive series which included 20 patients (14 Male, 6 Female) who suffered a primary rupture of the ACL. All patients received an ACLR using the semitendinosus autograft fixated using the T-Lock Osteotrans for the femoral fixation and BioactIF Osteotrans interference screw for tibial fixation (Fig. 1). The preparation of the autograft and femoral fixation are demonstrated in Figs. 2 and 3. Eight patients also suffered from concomitant meniscal damage (6 medial meniscus, 2 lateral meniscus). Of these, 5 patients received a meniscal refixation and 3 patients received a partial meniscectomy. The mean age at the time of surgery was 25.6 years (Range 17–44). Ethical clearance was acquired from the institutional ethical committee with the reference number S-488. All patients signed a written agreement to take part in this study.
The inclusion criteria comprised of the following points: Primary ACL rupture, preinjury Tegner score ≥ 4, skeletal maturity, < 45 years of age at the time of surgery. Exclusion criteria included active infection, bone fractures, injuries of the lateral collateral ligament and the posterior cruciate ligament, history of prior knee surgery and presence of chondromalacia greater than grade II according to Outerbridge[25].
During the preoperative examination, anterior sagittal laxity was objectively assessed by means of instrumented KT-1000 measurement KT-1000™ Knee Ligament Arthrometer® manufactured by MEDmetric® Corporation (http://www.medic alpro ductguide.com/companies/1364/medme tric_corp, MEDmetric® Corporation, 7542 Trade Street, San Diego, CA 92121; Patent no. 4,583,555) and a tension force of 134 N[1]. This was also examined on follow-up and compared to the contralateral side. Additionally, the following scores were assessed preoperatively and on follow-up: Tegner score, Lysholm score and IKDC subjective knee evaluation form[29, 3, 10]. Tegner score preinjury was also retrieved.
Postoperatively, all participants underwent standardized rehabilitation regimens. The postoperative rehabilitation program involved range of motion re-acquisition with full extension in the first two weeks. Prone hangs and bridging exercises were considered. Progressive weight bearing assisted by crutches was performed. Individuals were advised to avoid open-chain exercises and extension against resistance for the first six months. These postoperative rehabilitation regimens were uniform for all patients and were at times, individually tweaked as required. Such as in the case of accompanying meniscal damage.
Besides a conventional AP-Radiograph of the knee, the radiological evaluation also included Magnetic Resonance Imaging (MRI) of the knee. For all patients, an MRI was planned 1 and 3 years postoperatively. In total, 28 MRIs were done. Of these, 26 MRIs were conducted in the department of diagnostic and interventional radiology. The remaining two examinations were done in outpatient facilities. The 26 examinations were facilitated using a 70-cm open bore 3-T MR Scanner (Magnetom Verio, Siemens Healthineers, Erlangen, Germany) with an 18-channel total imaging matrix and a dedicated knee-coil. The patients were positioned feet-first and supine with the knee in a neutral position. The knee was positioned as close as possible to the isocenter of the magnet. In order to minimize movement artifacts, radiographers were advised to stabilize the knee joint. For morphologic imaging assessment of the knee, the in-house standard knee MRI protocol was used. It included proton-density weighted fat saturated sequences in all three imaging planes as well as a sagittal T1weighted sequence, a coronal proton-density weighted sequence and a sagittal 3D DESS-Sequence that was reformatted in all three planes.
All studies were evaluated by a musculoskeletal radiologist with 5 years of experience in musculoskeletal MRI. The radiologist determined the slice selection, magnification and windowing parameters. The Ambient light was kept at minimum during the reading sessions. Femoral tunnel enlargement was measured by subdividing the femoral tunnel into a proximal, mid and distal section on the coronal proton-density, coronal proton-density fat-saturated or coronal T1-weighted images. The diameter was measured perpendicular to the tunnel border. In patients with two MRI follow-up examinations the tunnel diameter was measured in similar positions in order to enable the assessment of a tunnel enlargement. The T-Lock anchoring device was evaluated using a 4-point classification system adapted to Cossey et al. and classified as intact, deformed, fractured or not visible[5]. In accordance to Figueroa et al., the graft signal was evaluated with regards to the predominating signal intensity[7]. The bone-graft interface was evaluated with regard to the presence of a fluid-intense rim surrounding the graft within in the tunnel using a 3-point scale (no fluid signal, < 50% fluid signal and > 50% fluid signal). Furthermore, Bone-Marrow-Edema (BME) was classified binarily as either absent or present[26].
The statistical analysis was performed using SPSS version 26. A p-value of 0.05 significance level. Paired t-tests were performed for normally distributed data and non-parametric tests for independent sample was used to analyze abnormally distributed data.
Data acquisition and analysis were performed in compliance with protocols approved by the Ethical Committee of the medical faculty of the Ruprecht-Karls-University Heidelberg (Reference number: S-488). The study was registered in the German Register of Clinical Studies and was conducted in accordance with the Declaration of Helsinki. All Patients gave written consent to participate in the study.