The Influence of Intercondylar Notch Shape and Size on the Treatment Algorithm for Anatomic Anterior Cruciate Ligament Reconstruction☆
Introduction
In 1938, Palmer first suggested a close relationship between the anterior cruciate ligament (ACL) and the intercondylar notch.1 Anatomically, the ACL is located tight against the intercondylar notch roof during full extension, with forces concentrated on the middle of the ligament.2 Consequently, many studies have focused on determining associations between the intercondylar notch and ACL injury risk. Recent research in this area has concentrated on establishing how the notch may affect intraoperative decision-making during ACL reconstruction as well as on how the notch may affect the ACL graft postoperatively. This article provides a historic overview of the research performed on notch morphology as related to ACL injury risk. Furthermore, guidelines will be provided for intraoperative decision-making as well as regarding postsurgical considerations.
Section snippets
Historical Perspective
One of the first studies on the relationship between intercondylar notch size and ACL injury risk compared notch view radiographs between subjects with and without ACL injury, specifically assessing intercondylar notch size. The results indicated that a narrowed posterior notch arch predisposes patients to ACL injury.3 A subsequent study used computed tomography (CT) to evaluate uninjured and unilateral or bilateral ACL-injured subjects, finding a statistically significant smaller notch size
Measuring Notch Size
Some of the discrepancies between the results of various studies might be explained by differences in intercondylar notch size measurement methodologies. For example, whereas Davis et al12 located the middle of the tibial spine on a coronal MRI scan to measure notch width and the ACL, Cha et al13 used an axial MRI to measure notch width, width index, area, and transverse angle and a sagittal MRI to measure sagittal notch angle. Dienst et al14 also used MRI scans, but, in contrast to other
Considerations for ACL Reconstruction
Regardless of if intercondylar notch size affects ACL injury risk, this characteristic is certainly important to consider during ACL reconstruction. A narrow notch can make it difficult to place guide pins, especially during double-bundle ACL reconstruction when drilling the femoral tunnels through an anteromedial portal. With a narrow notch, it is difficult to drill femoral tunnels without damaging the medial femoral condyle (Fig. 7). In such cases, some surgeons recommend performing selective
Intercondylar Notch Dimensions and ACL Graft Failure
Notch size may not only influence native ACL injury risk but also affect the ACL graft after reconstruction. A recent study evaluated femoral intercondylar notch dimensions intraoperatively to determine if a small notch increases the risk for graft failure after individualized anatomical single- or double-bundle ACL reconstruction. For assessments, 137 primary single- or double-bundle ACL reconstruction cases with at least 2 years follow-up were included. Of these, intraoperative measurements
Conclusion
The intercondylar notch and ACL are closely related. Although patients with a narrow intercondylar notch may be predisposed to ACL injury, differing 2D and 3D methodologies for measurements make cross-study comparisons difficult. It is important to take the notch into account during anatomical ACL reconstruction. In particular, a narrow, A-shaped notch may make it difficult to drill the femoral tunnel from the medial portal and may not accommodate the double-bundle technique. However, if these
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The author did not receive any outside funding or grants directly related to the research presented in this article. The author states that this article is an original work only submitted to this journal.