A Higher Initial Tensioning Force of an ACL Graft Results in a Higher Graft Force After Screw Fixation Irrespective of the Screw Diameter: A Biomechanical Study

Background: The intra-articular graft force (IAGF) in anterior cruciate ligament reconstruction decreases quickly over the first hours after surgery. Nevertheless, little is known about whether the initial extra-articular tensioning force (EATF) and screw diameter affect the graft force after fixation. Purpose: To investigate the effects of different EATFs on the IAGF of a soft tissue graft fixated via a bioabsorbable interference screw over 100 minutes after fixation and to evaluate the effects of different screw diameters within 1 mm of the tunnel width during this process. Study Design: Controlled laboratory study. Methods: In this biomechanical study, a porcine quadruple-strand soft tissue graft was inserted into the tibial anterior cruciate ligament tunnel. On the extra-articular side, 3 loads were applied during retrograde insertion of the bioabsorbable interference screw (6, 7, and 8 mm): 20 N, 80 N, and maximum manual EATF (Nmax). Nine study groups consisting of 10 tibiae each were created to test the effects of different EATFs and screw sizes. The IAGF was measured up to 100 minutes after the EATF was released. Results: An EATF ≥80 N resulted in a larger IAGF for all screw sizes at 100 minutes. There were no significant associations between the IAGF at 100 minutes and different screw diameters. Inserting the tibial screw significantly increased the IAGF in all groups, with the exception of Nmax applied in groups with 7- or 8-mm screws. When compared with the end of screw insertion, after the release of the EATF, the IAGF dropped by 55% to 77 % at 100 minutes. Conclusion: An initial EATF ≥80 N is associated with a significantly larger IAGF at 100 minutes in this cadaveric simulation. The IAGF in soft tissue grafts decreased substantially after the retrograde placement of an interference screw. A recommendation regarding screw diameter with respect to the IAGF cannot be given. Clinical Relevance: To obtain a higher residual graft force after bioabsorbable interference screw fixation, an initial EATF ≥80 N should be applied according to this model. The significant decrease in graft force after the release of the EATF indicates that the reconstructed knee cannot be mechanically stabilized after the surgery.

A COMPARATIVE STUDY OF FUNCTIONAL OUTCOME BETWEEN BIOABSORBABLE INTERFERENCE SCREW AND ENDOBUTTON FIXATION ON FEMUR IN ARTHROSCOPIC ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Background: This prospective clinical study was performed to compare the Functional outcomes between Bioabsorbable Interference Screw And Endobutton Fixation On Femur In Arthroscopic Anterior Cruciate Ligament Reconstruction .Methods: from April 2018 to June 2019, 126 patients (16 females and 110 males) aged 18 to 50 years were enrolled in this study. Patients were randomly divided into two groups including Anterior Cruciate Ligament (ACL) reconstruction with Bioabsorbable interference screw fixation called group A (N=63) and other group B that underwent ACL reconstruction with Endobutton fixation (N=63). Functional outcomes were compared for TL (Tegner Lysholm) Score preoperatively, at 3 months and 6 months. All data were collected and analyzed with the help of suitable statistical parameters.Results: The endobutton fixation yielded better outcome in terms of instant stability of the graft and functional outcome at the end of 6 month. We are currently awaiting long term results to verify whether or not these early results persist. Key words: Bioabsorbable Interference Screw, Endobutton Fixation, Anterior Cruciate Ligament, TL Score.

Delayed Tibial Osteomyelitis after Anterior Cruciate Ligament Reconstruction with Hamstrings Autograft and Bioabsorbable Interference Screw: A Case Report and Review of the Literature

Osteomyelitis following arthroscopically assisted anterior cruciate ligament (ACL) reconstruction has rarely been reported in the literature. We report a case of a 20-year-old female who had delayed tibial osteomyelitis and a pretibial cyst with culture-positive, oxacillin sensitive Staphylococcus epidermidis 15 months after an ACL reconstruction with hamstring autograft. Soft tissue fixation within the tibial tunnel was with a poly-L-D-lactic acid (PLDLA) bioabsorbable interference screw. The patient underwent surgical treatment with curettage, debridement, hardware removal, and bone grafting of the tibial tunnel followed by a course of intravenous antibiotics. Arthroscopic evaluation demonstrated an intact ACL graft without any evidence of intra-articular infection. The patient returned to collegiate athletics without any complications. While the most common biologic complications include pretibial cysts, granuloma formation, tunnel widening, and inflammatory reactions, infection is exceedingly rare. Late infection and osteomyelitis are also rare but can occur and should be considered in the differential diagnosis.

Functional outcome of anterior cruciate ligament reconstruction with quadruple hamstring tendon graft using EndoButton and bioabsorbable interference screw: minimum 2-year follow-up

<p class="abstract"><strong>Background:</strong> Anterior cruciate ligament (ACL) is the most common ligament to be torn in the knee joint and ACL reconstruction (ACLR) is one of the most commonly performed surgery in orthopaedics nowadays. This study evaluated short term results of anterior cruciate ligament reconstruction with quadruple hamstring tendon (QHT) graft using EndoButton for femoral fixation and Bio absorbable interference screw for tibial fixation.</p><p class="abstract"><strong>Methods:</strong> Out of the<strong> </strong>68 patients who underwent single-bundle ACLR with QHT graft using EndoButton for femoral fixation and Bio absorbable interference screw for tibial fixation, 60 patients were followed up for a minimum period of 2 years. Patients were followed up at regular intervals and evaluation was done using the anterior drawer test, Lachman test, pivot-shift test, modified Cincinnati rating system and Tegner-Lysholm knee scoring scale.<strong></strong></p><p class="abstract"><strong>Results:</strong> There was improvement in the Lachman test and pivot-shift test at 2 year follow-up, from grade 2 (n=47) or grade 3 (n=6) to grade 1 (n=17) or grade 0 (n=42) and from grade 1 (n=38) or grade 2 (n=12) to grade 1 (n=14) or 0 (n=45), respectively. The mean Modified Cincinnati score and Tegner-Lysholm knee score improved from 59.57 to 99.03 and 64.45 to 98.87 respectively at 2 year follow-up. Complications occurred in 3 patients, a re-rupture due to trauma at 1 year after surgery, development of a cyclops lesion with restricted range of motion and a superficial infection at the graft harvest site.</p><p><strong>Conclusions:</strong> The two year follow-up results of ACLR with QHT graft using EndoButton for femoral fixation and bioabsorbable interference screw for tibial fixation are satisfactory and comparable with other modalities of graft fixation.</p>