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BACKGROUND: "Why try to convert other collagen substitutes into ligament if the original can be preserved?" said Sherman1. Nowadays, reconstruction became the gold standard treatment for ACL injuries. Despite current treatment, secondary knee osteoarthritis has been described in more than 70% of the injured patients after 10 years follow up.2 Recent studies have reported that tears involving the proximal ACL have an intrinsic healing response. This response has been compared to the one observed in MCL injuries.3, 4 OBJECTIVE: The aim of this study is to initiate a scientific analysis of our experience in patients diagnosed with an acute, proximal ACL tear treated with a primary repair arthroscopic technique. We suggest the creation of a symposium that reconsiders the ACL repair as a tool for treatment, on a selected subset of patients. METHODS: We analyzed retrospectively the data of 12 consecutive patients diagnosed clinically and radiologically (MRI) with proximal ACL tears in our clinic. The inclusion criteria were: proximal ACL tear (type 1 tear in Sherman´s classification), good remaining ACL quality tissue and less than 3 months from injury. The mean age at time of surgery was 33 years (16 to 55). Patients included in this study are athletes either at an amateur or professional level. The technique consists of an anatomical reinsertion of native ACL by reinforcing the anteromedial and posterolateral bundles of the ACL with a series of high strength locking Bunnell-type sutures, moving up the ligament from distal to proximal with an arthroscopic suture passer. The normal ACL insertional footprint within the notch is then debrided to provide a bleeding surface for healing. Finally, the torn ligament is opposed to the native footprint using 1-2 absorbable anchors that recreate the anatomic bundle insertional sites of the native ACL. RESULTS: Associated injuries were found in 7 of the 12 patients, these included 4 knees with lateral and 1 with medial meniscal tear which were repaired in the same procedure. Also, one knee had a medial bucket handle tear, partial meniscectomy was performed, and one knee with a combined ACL/MCL injury in which the MCL was simultaneously repaired. In our ongoing series, were excluded patients that had sustained complex knee injuries with multi-ligament damage (except ACL/MCL injuries), those with ACL re-ruptures, and previous knee surgery with cartilage repair procedures. Validated functional outcomes scores were collected after a mean follow up of 20 months (14-26). For the IKDC subjective score 11 of 12 patients rated their knees as normal or nearly normal. Lachman and Pivot Shift was negative in all patients. Lysholm score postoperatively averaged 93.5 ± 7; preoperatively 48 ± 7. Tegner preinjury 7.5 ± 1.2 postinjury: 7 ± 1.4. The KT-1000 knee arthrometer, objectively measured < 3mm of anterior tibial motion relative to the femur in the injured knee compared to the non-injured knee at all levels of force, including manual max tests, in all patients included in the study. No comp...

Initial stability of cementless stems used in total hip arthroplasty (THA) is critical for subsequent osseointegration at the bone/implant interface. In the setting of revision THA, there is frequently less intact femoral bone available for fixation of the new stem. This study aims to compare the initial fixation stability between a cylindrical and tapered stem, designed for diaphyseal fixation in a revision THA setting, with increasing bone defect severity. Using finite element analysis, severe Paprosky Type III femoral bone defects were simulated. The cylindrical stem had a 13.3% higher construct stiffness as compared to the tapered stem for the least severe bone defect modeled. In contrast, for the most severe bone defect, the tapered stem showed a 12.3% higher construct stiffness than the cylindrical stem. At the bone/implant interface, the tapered design resulted in less than 20 μm of maximum tangential micromotion for all the bone defect models, whereas the cylindrical stem exceeded 20 μm for all and was as high as 70 μm in the most severe case. Given the limitations of the models presented, the results suggest the tapered stem obtained superior initial fixation as compared to cylindrical stem with increasing bone defect severity.

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