Anatomic placement of the femoral tunnel by a modified transtibial technique using a large-offset femoral tunnel guide: A cadaveric study.

BACKGROUND: The purpose of this study was to assess whether the use of a 10 mm-offset femoral tunnel guide with lateral rotation allows more anatomic placement of femoral tunnel compared to the conventional seven millimeters-offset guide in transtibial anterior cruciate ligament (ACL) reconstruction. METHODS: Sixteen knees from eight cadavers were employed. Four guide pins were inserted using a seven millimeters- or 10mm-offset transtibial femoral tunnel guide with or without lateral rotation technique in each knee. The pin positions were assessed by the quadrant method. Femoral tunnels were then reamed along the guide pins inserted through the laterally rotated guides: seven millimeters-offset for right knees and 10 mm- offset for left knees. The percentages of the coverage of native ACL femoral footprints were analyzed. RESULTS: Lateral rotation of the seven millimeters- & 10mm-offset guides placed the pins more posteriorly (lower) by 15.7% and 24.5%, respectively (p<0.001). Laterally rotated 10 mm-offset guides placed the guide pins more distally by 6.2% and more posteriorly by 6.6% than laterally rotated seven millimeters-offset guides. Laterally rotated seven millimeters- & 10 mm-offset guides resulted in average coverage of 52.3% and 61.8% of the native ACL femoral footprints, respectively (p<0.001). The lengths of the tunnels were acceptable. CONCLUSION: Compared to the conventional seven millimeters-offset guide, the use of a 10mm-offset femoral tunnel guide with lateral rotation allows more anatomic placement of femoral tunnel in transtibial ACL reconstruction. CLINICAL RELEVANCE: Anatomic single bundle ACL reconstruction by transtibial technique seems feasible by using the technique described in this study.

Selective Medial Release Technique Using the Pie-Crusting Method for Medial Tightness During Primary Total Knee Arthroplasty.

BACKGROUND: The pie-crusting method is popular in releasing lateral tightness during primary total knee arthroplasty (TKA) but is not well described for medial release. We established a selective medial release technique using the pie-crusting technique and investigated the effectiveness and safety of the technique during primary TKA. METHODS: We retrospectively reviewed 729 primary TKAs with varus deformity between October 2009 and June 2012. Medial tightness in flexion was released by traditional subperiosteal stripping for the anterior portion of the medial collateral ligament (aMCL). Medial tightness in extension was released by the pie crusting for the tight fibers in the posterior portion of the MCL and/or posteromedial corner structures (pMCL/PMCS). Clinical outcomes were evaluated by Knee Society (KS) scores and the Western Ontario and McMaster Universities Osteoarthritis Index. Any complications, including late medial instability that may be related to our surgical technique, were carefully inspected. RESULTS: Among the 729 knees, 170 (23.3%) required subperiosteal stripping for balancing in flexion only, 186 (25.5%) required the pie-crusting for balancing in extension only and 142 (19.5%) required subperiosteal stripping and the pie-crusting for balancing in flexion and extension. The KS knee score was improved from 52.5 to 83.4, KS function score from 58.2 to 91.9, and Western Ontario and McMaster Universities Osteoarthritis Index from 42.7 to 21.8 (P < .001, all). No specific complications related to our technique were identified. CONCLUSIONS: The selective medial release technique appears to be an effective and safe method to obtain a balanced mediolateral gap in primary TKA.