Intercondylar Notch Size Can Be Predicted on Preoperative Magnetic Resonance Imaging

Association of Smaller Intercondylar Notch Size With Graft Failure After Anterior Cruciate Ligament Reconstruction

Background

Smaller intercondylar notch sizes have been consistently associated with a predisposition for primary anterior cruciate ligament tears.

Purpose

To evaluate the association between intercondylar notch size, graft size, and postoperative complications, including knee stiffness and return to the operating room, after primary anatomic anterior cruciate ligament reconstruction (ACLR).

Study Design

Case-control study; Level of evidence, 3.

Methods

This was a retrospective analysis of prospectively collected data from consecutive patients who underwent anatomic single-bundle primary ACLR using a bone-patellar tendon-bone or quadriceps tendon autograft performed by fellowship-trained orthopaedic sports medicine surgeons between April 2009 and August 2019. Graft failure was defined as patient report of instability, pathologic laxity on clinical examination, or graft rerupture confirmed by magnetic resonance imaging and/or subsequent arthroscopy. To ensure the purposeful selection of covariates, univariate analyses were conducted on the list of potential confounders selected a priori, and those with a significance value of P < .10 were considered for the multivariate regression model. Covariates found to be statistically significant with univariate analysis were patient age, notch size, and graft type. After validating all potential covariates, they were added to the regression model and then eliminated in a stepwise fashion.

Results

In total, 252 patients were included for analysis (99 bone-patellar tendon-bone and 153 quadriceps tendon autograft; age, 22.2 ± 7.0 years; graft size, 9.8 ± 1.0 mm; time to follow-up, 50.4 ± 28.9 months). Knee stiffness developed in 23 patients (9.1%), and 15 grafts failed (6.0%). Smaller notch size on magnetic resonance imaging was significantly associated with graft failure (P = .005). There was a significantly higher risk of graft failure with notch size <16 versus ≥16 mm (17.6% vs 2.3%; P = .005) with an odds ratio (OR) of 5.0 (95% CI, 1.7-15.1; P = .004). Notch size <15 mm was associated with the highest risk of graft failure (22.2%; OR, 5.8; 95% CI, 1.6-20.6; P = .006). There was no significant association between notch size or graft-notch size ratio and knee stiffness, meniscal injury, or cartilage damage at the time of ACLR, regardless of graft type.

Conclusion

Intercondylar notch size <16 mm was associated with a 5-fold increased risk of graft failure after primary anatomic ACLR.

Femoral intercondylar notch: Accuracy of a novel MRI measurement protocol

OBJECTIVE

The most common mechanical complication following an anterior cruciate ligament (ACL) reconstruction is joint stiffness, due in part to cyclops syndrome. A narrow intercondylar notch is an anatomical risk factor. A reliable preoperative notch measurement would help anticipate proper graft size, or plan a notchplasty during the ligament reconstruction, if necessary. No study has yet assessed the accuracy of the methods used to measure notch size.

HYPOTHESIS

The novel measurement protocol proposed in this study would be more reproducible than the reference technique.

METHODS

A total of 20 preoperative knee MRIs performed during the assessment of an ACL rupture were randomly selected. The notch size was measured using 2 methods: traditional (ratio of the notch and metaphyseal widths measured on a line drawn through the popliteal groove) and novel. The latter was measured using the same ratio but took into account the notch width in its proximal third, according to a coronal slice that passes through the ACL tibial attachment. Three orthopedic surgeons with different levels of experience (senior surgeon, junior surgeon and surgical resident) performed these measurement protocols twice on anonymized MRI scans, 10days apart. Spearman's rank correlation coefficient was used to assess the intraobserver correlations and a concordance index was used to assess the interobserver correlations. The influence of the second MRI reading was analyzed with a bootstrap test.

RESULTS

The mean intraobserver reliability was 0.73 for the reference method and 0.83 for the proposed method. The values of the bootstrap tests were higher for the proposed method (0.45 vs. 0.45 and 0.70; p<05 for interobserver; 0.49 vs. 0.69 and 0.62; p<05 for intraobserver).

CONCLUSION

The proposed measurement protocol showed a higher reproducibility in assessing notch size than the traditional method. This technique therefore provides a reliable assessment of the intercondylar notch width.

LEVEL OF EVIDENCE

IV; retrospective study.

Current trends in the anterior cruciate ligament part II: evaluation, surgical technique, prevention, and rehabilitation

Clinical evaluation and management of anterior cruciate ligament (ACL) injury is one of the most widely researched topics in orthopedic sports medicine, giving providers ample data on which to base their practices. The ACL is also the most commonly treated knee ligament. This study reports on current topics and research in clinical management of ACL injury, starting with evaluation, operative versus nonoperative management, and considerations in unique populations. Discussion of graft selection and associated procedures follows. Areas of uncertainty, rehabilitation, and prevention are the final topics before a reflection on the current state of ACL research and clinical management of ACL injury. Level of evidence V.

The radiographic tibial spine area is correlated with the occurrence of ACL injury

PURPOSE

The purpose of this study was to reveal the possible influence of the tibial spine area on the occurrence of ACL injury.

METHODS

Thirty-nine subjects undergoing anatomical ACL reconstruction (30 female, 9 male: average age 29 ± 15.2) and 37 subjects with intact ACL (21 female, 16 male: average age 29 ± 12.5) were included in this study. In the anterior-posterior (A-P) and lateral knee radiograph, the tibial spine area was measured using a PACS system. In axial knee MRI exhibiting the longest femoral epicondylar length, the intercondylar notch area was measured. Tibial spine area, tibial spine area/body height, and tibial spine area/notch area were compared between the ACL tear and intact groups.

RESULTS

The A-P tibial spine area of the ACL tear and intact groups was 178 ± 34 and 220.7 ± 58mm², respectively. The lateral tibial spine area of the ACL tear and intact groups was 145.7 ± 36.9 and 178.9 ± 41.7mm², respectively. The tibial spine area was significantly larger in the ACL intact group when compared with the ACL tear group (A-P: p = 0.02, lateral: p = 0.03). This trend was unchanged even when the tibial spine area was normalized by body height (A-P: p = 0.01, lateral: p = 0.02). The tibial spine area/notch area of the ACL tear and intact groups showed no significant difference.

CONCLUSION

The A-P and lateral tibial spine area was significantly smaller in the ACL tear group when compared with the ACL intact group. Although the sample size was limited, a small tibial spine might be a cause of knee instability, which may result in ACL injury.

LEVEL OF EVIDENCE

Level III.

The intercondylar fossa-A narrative review

The intercondylar fossa (“intercondylar notch,” IN) is a groove at the distal end of the femur, housing important stabilizing structures: cruciate ligaments and meniscofemoral ligaments. As the risk for injury to these structures correlates with changes to the IN, exact knowledge of its morphology, possible physiological and pathological changes and different approaches for evaluating it are important. The divergent ways of assessing the IN and the corresponding measurement methods have led to various descriptions of its possible shapes. Ridges at the medial and lateral wall are considered clinically important because they can help with orientation during arthroscopy, whereas ridges at the osteochondral border could affect the risk of ligament injury. Changes related to aging and sex differences have been documented, further emphasizing the importance of individual assessment of the knee joint. Overall, it is of the utmost importance to remember the interactions between the osseous housing and the structures within.