Intercondylar Notch Stenosis of Knee Osteoarthritis and Relationship between Stenosis and Osteoarthritis Complicated with Anterior Cruciate Ligament Injury: A Study in MRI

Predictors of lower knee function improvement two years after anterior cruciate ligament reconstruction

OBJECTIVES

The extent to which knee functions improve after anterior cruciate ligament reconstruction (ACLR) varies. This study aimed to determine the factors that affect lower knee function improvement after two years of ACLR.

METHODS

The study included 159 patients who underwent ACLR in the Indonesian ACL community between August 2018 and April 2020. The concomitant injury and graft types of ACLR were determined using patients' pre-surgical MRI and medical records. The five subscales of the knee injury and osteoarthritis outcome score (KOOS) were used to evaluate the patient at baseline, first year, and second year following ACLR. A linear mixed-effect model (LMEM) was used to predict the longitudinal improvement models for the five-subscales KOOS score after ACLR.

RESULTS

The LMEM predicted lower KOOS subscales scores improvements by 0.5 for QOL, 0.1 for symptom, ADL, and QOL, and 0.2 for sports/recreation, respectively, for a one score increase of age and time from injury to surgery. Male patients had higher KOOS subscale scores with the improvement of pain, symptom, and ADL by 5.7, 5.9, and 6.3 compared to female patients, respectively, while patients with patellar tendon grafts had lower improvement of KOOS score pain by 6.5 compared to hamstring tendon grafts.

CONCLUSION

As the age and time from injury to surgery increased, the KOOS subscales scores of QOL and symptoms, ADL, sports/recreation, and QOL decreased. Male patients reported higher KOOS subscales scores for pain, symptoms, and ADL, while patients with patella tendon grafts had a lower improvement in pain score.

Individual and Combined Anatomic Risk Factors for the Development of an Anterior Cruciate Ligament Rupture in Men: A Multiple Factor Analysis Case-Control Study

BACKGROUND

No comparative studies have evaluated anatomic risk factors in a large cohort including both patients with anterior cruciate ligament (ACL) ruptures and healthy participants.

PURPOSE

To determine which anatomic parameters are independently associated with an ACL rupture and the diagnostic values of the individual and combined anatomic parameters.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A total of 352 male patients who underwent arthroscopic ACL reconstruction because of a primary ACL rupture and 350 age-, sex-, body mass index-, and side dominance-matched healthy participants were included. Measurements of 32 previously determined parameters and 7 calculations were performed. Between-group differences were calculated. Univariate and multivariate logistic regression models and receiver operating characteristic curve analysis were conducted for the individual and combined independently associated factors.

RESULTS

The mean age and body mass index of all participants were 29.9 ± 7.7 years and 27.2 ± 3.1, respectively. There were significant differences between the groups regarding the notch width (NW), notch shape index, anterior tibial slope, notch width index, NW-eminence width (NW:EW) ratio, notch height, axial lateral wall angle, medial intercondylar ridge thickness, alpha angle, medial tibial depth (MTD), lateral tibial slope (LTS), coronal tibial plateau width, eminence width index, tibial proximal anteroposterior distance (TPAP), lateral condylar anteroposterior distance (LCAP)/TPAP, ACL cross-sectional area, ACL volume, medial and lateral meniscal cartilage height, medial and lateral meniscal cartilage angle (MCA), and medial and lateral meniscal cartilage bone height. The NW:EW ratio (odds ratio [OR], 4.419; P = .017), MTD (OR, 8.617; P = .001), LTS (OR, 2.254; P = .011), LCAP/TPAP (OR, 2.782; P = .037), and medial MCA (OR, 1.318; P = .010) were independently associated with the development of an ACL rupture. Combining the independently associated factors revealed a sensitivity of 93% and a specificity of 94% (area under the curve, 0.968).

CONCLUSION

Patients with ACL ruptures could be distinguished from uninjured controls with high sensitivity and specificity via the combined use of the NW:EW ratio, MTD, LTS, LCAP/TPAP, and medial MCA. In clinical practice, these findings may contribute to the development of preventive strategies for ACL ruptures.

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.

Notch Volume Measured on Magnetic Resonance Imaging Is Better Than 2-Dimensional Notch Parameters for Predicting Noncontact Anterior Cruciate Ligament Injury in Males

PURPOSE

To evaluate and compare intercondylar notch volume with other 2-dimensional notch parameters (measured on magnetic resonance imaging [MRI]) for prediction of noncontact anterior cruciate ligament (ACL) injury in males.

METHODS

Retrospective case-control study in males based on MRI images. The case group consisted of 80 noncontact ACL-injured males and a control group of 80 age- and height-matched ACL-intact males. Inclusion criteria were 18 to 50 years old, full-thickness tear, MRI obtained within 1 year of injury, and ACL tear visually documented during arthroscopy. Multiligamentous, bilateral, or concomitant bony injuries were excluded. Notch volume and 2D parameters in both planes, including notch depth, notch width, intercondylar notch angle, notch-width index, and notch-shape index, were measured on MRI and compared. Slice interval was included in the formula for notch-volume assessment. Bivariate Pearson correlation between notch volume and 2D parameters was estimated. Multivariate conditional logistic regression analysis was used for predictor model. Receiver operating characteristic (ROC) curves were plotted.

RESULTS

All MRIs had a standard slice thickness of 3 mm and slice interval of 0.3 mm. Notch volume (P < .001), notch angle in the axial plane (P = .001), and notch width in the coronal plane (P = .009) were significantly smaller in the ACL-injured group. Notch volume had inconsistent and negligible to low correlation with 2D parameters. Notch volume was the only significant contributor in the predictor model (P < .001). ROC curve showed that notch volume had highest area under the curve of 84.1% and optimal cutoff at 7.1550 cm³ (specificity, 88.7%; sensitivity, 65%).

CONCLUSION

Significantly smaller intercondylar notch volume is associated with noncontact ACL injury in men and is the most important predictor for such an injury (optimal cutoff of 7.1550 cm³). Two-dimensional notch parameters are inconsistently associated with noncontact ACL injury in men, and none of the 2D parameters can be used as a surrogate for notch volume. Two-dimensional notch parameters fare poorly in predicting noncontact ACL injury in males. Notch volume measurement should include slice interval as a factor.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Correlation between notch width index assessed via magnetic resonance imaging and risk of anterior cruciate ligament injury: an updated meta-analysis

PURPOSE

To analyze the correlation between notch width index (NWI) and/or femoral intercondylar notch width (NW) assessed by magnetic resonance imaging (MRI) and risk of anterior cruciate ligament (ACL) injury.

METHODS

We searched the PubMed, Embase, China National Knowledge Infrastructure and Wanfang databases for literature reporting a correlation between ACL injury and NWI and/or NW. Subgroup analyses were stratified by ethnicity, sex and control source. The weighted mean difference (WMD) and 95% confidence intervals (95% CIs) were calculated for the ACL injury cases and controls using random- or fixed-effects models. Begg's test and sensitivity analyses were applied to assess publication bias and stability of the results, respectively.

RESULTS

Twenty-eight eligible studies were finally enrolled. The NW was significantly narrowerin the ACL injury cases than in the control cases (pooled WMD, - 1.88 [95% CI, - 2.43 to - 1.32]). The results were similar when stratified by ethnicity and sex. Similarly, the NWI was lower in ACL injury cases than in the controls. Asian populations presented similar results when stratified by ethnicity, among the self-control group when stratified by control source, and among men when stratified by sex. No publication bias was identified; however, the sensitivity analysis suggested unstable results in the NWI subgroup analysis.

CONCLUSIONS

The current meta-analysis evidenced that the NW assessed via MRI was significantly smaller in ACL injury cases than in the controls. The NWI was lower in ACL injury cases among men. Prevention strategies for ACL injury could be applied for people with intercondylar notch stenosis.

Knee Morphological Risk Factors for Anterior Cruciate Ligament Injury: A Systematic Review

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction incidence has increased substantially in the past 25 years. Recently, there has been a focus on knee morphology as a contributor to ACL injury risk. The purpose of this study was to systematically review the literature to assess the influence of knee morphology on ACL injury.

METHODS

In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, PubMed, Embase, and MEDLINE were searched in September 2017 for studies reporting on knee morphology and ACL injury. The search was updated in June 2018. The following inclusion criteria were used: English language; full text available; Level-I, II, or III evidence; human studies; and skeletally mature patients.

RESULTS

After systematically screening 6,208 studies, 65 studies met the inclusion/exclusion criteria. Three additional studies were identified in the search update, for a total of 68 studies comprising 5,834 ACL-injured knees. Intercondylar notch stenosis, most commonly defined by an "A-shaped" notch, decreased notch width, or decreased notch width index, was the most commonly reported femoral morphological risk factor for ACL injury. Increased femoral condylar offset ratio (>63%) and decreased condylar radius of curvature also were associated with an increased risk of ACL injury. Increased medial and lateral tibial slopes were the most commonly reported tibial risk factors. A smaller tibial eminence, reduced ACL size, and poor tibiofemoral congruity were also associated with increased injury risk.

CONCLUSIONS

Intercondylar notch stenosis, variations in sagittal condylar shape, increased tibial slope, reduced tibial eminence size, poor tibiofemoral congruity, and reduced ACL size are substantial risk factors for ACL injury. In future research, it would be valuable to identify a slope beyond which slope correction should be performed concomitantly with ACL reconstruction, and to determine whether an optimal relationship of notch size to graft size exists. To achieve optimal outcomes, the osseous morphological risk factors should be considered in individualized anatomic ACL reconstructions.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Relationship between Femoral Intercondylar Notch Narrowing in Radiography and Anatomical and Histopathologic Integrity of Anterior Cruciate Ligament in Patients Undergoing Total Knee Replacement Surgery

BACKGROUND

The presence of cruciate ligaments is very important for normal knee kinematics. Knee arthroplasty prostheses, in which these ligaments are maintained, have better kinematics. The aim of the present study was to investigate the association between femoral intercondylar notch (FIN) narrowing in radiography and clinical and histopathologic integrity of anterior cruciate ligament (ACL) in patients undergoing knee replacement surgery.

METHODS

FIN index was measured in tunnel view radiography of the knees of 102 candidates of knee replacement surgery. The anatomical status of ACL was also examined during total knee arthroplasty (TKA). ACL was removed and sent for histopathologic examination to assess its degeneration rate. The association between the FIN index and the clinical and histopathological health of ACL was investigated.

RESULTS

Among 102 patients with mean age of 69.73 ± 7.81 years , 39 patients (38.32%) had no or torn ACL, 31 patients (30.39%) had weak ACL, and 32 (31.37%) had normal ACL. There was a significant association between age and clinical status of ACL during surgery (P=0.017). There was a significant difference in FIN and ACL health status during surgery between the two groups with an index of more and less than 0.252 (P=0.019 and P=0.019, respectively). There was no significant difference in the mean total degeneration score (TDS) of ACL between the two groups with FIN more and less than 0.252 (P=0.816).

CONCLUSION

There was a significant difference between the age and FIN narrowing (less than 0.252) as well as ACL clinical status during surgery. FIN narrowing had no significant effect on the severity of ACL degeneration and there was no significant difference in the severity of degenerative histopathologic changes between healthy and attenuated ACLs. This indicates that if ACL exists, although apparently attenuated, it has the histologic characteristic of a healthy ligament.

Statistical shape modelling reveals large and distinct subchondral bony differences in osteoarthritic knees

Knee osteoarthritis (OA) results in changes such as joint-space narrowing and osteophyte formation. Radiographic classification systems group patients by the presence or absence of these gross anatomical features but are poorly correlated to function. Statistical-shape modelling (SSM) can detect subtle differences in 3D-bone geometry, providing an opportunity for accurate predictive models. The aim of this study was to describe and quantify the main modes of shape variation which distinguish end-stage OA from asymptomatic knees. Seventy-six patients with OA and 77 control participants received a CT of their knee. 3D models of the joint were created by manual segmentation. A template mesh was fitted to all meshes and rigidly aligned resulting in a set of correspondent meshes. Principal Component Analysis (PCA) was performed to create the SSM. Logistic regression was performed on the PCA weights to distinguish morphological features of the two groups. The first 7 modes of the SSM captured >90% shape variation with 6 modes best distinguishing between OA and asymptomatic knees. OA knees displayed sub-chondral bone expansion particularly in the condyles and posterior medial tibial plateau of up to 10 mm. The model classified the two groups with 95% accuracy, 96% sensitivity, 94% specificity, and 97% AUC. There were distinct features which differentiated OA from asymptomatic knees. Further research will elucidate how magnitude and location of shape changes in the knee influence clinical and functional outcomes.

Association Between Magnetic Resonance Imaging-Measured Intercondylar Notch Dimensions and Anterior Cruciate Ligament Injury: A Meta-analysis

PURPOSE

To explore the association between the magnetic resonance imaging (MRI)-measured intercondylar notch dimensions, including the intercondylar notch width (NW) and intercondylar notch width index (NWI), and the risk of anterior cruciate ligament (ACL) injury by performing a meta-analysis of studies that relied on the multiplanar imaging and soft-tissue visualization strengths of MRI.

METHODS

The MEDLINE, Embase, and SportDiscus databases were searched from inception to March 2017. Observational studies reporting on the associations of the NWI and NW with ACL injury were retrieved. A random-effects model was used to calculate the overall weighted mean difference (WMD) between the ACL injury group and control group.

RESULTS

A total of 20 studies were included in this meta-analysis. The combined data showed that subjects with ACL injury, as compared with the control group, had a significantly decreased NW (pooled WMD, -1.53 [95% confidence interval, -1.81 to -1.25]; P < .00001) and NWI (pooled WMD, -0.02 [95% confidence interval, -0.03 to -0.01]; P < .00001). Similar findings were observed in subgroup analyses in terms of different injury mechanisms. No significant difference in NWI was found in the axial view. A significantly decreased NW and NWI were found in other plane views. The sensitivity analyses after the exclusion of studies enrolling only athletes or skeletally immature subjects reached similar outcomes. The Begg rank correlation test showed no publication bias.

CONCLUSIONS

With the accumulation of evidence, this meta-analysis concluded that the NW and/or NWI measured by MRI was significantly lower in ACL-injured patients than in control subjects. For persons with a narrow intercondylar notch, preventive measures can be prepared for the prevention of ACL injuries.

LEVEL OF EVIDENCE

Level III, meta-analysis of Level II and III studies.

Comparison of magnetic resonance imaging for patients with acute and chronic anterior cruciate ligament tears

To compare the direct and indirect signs on magnetic resonance imaging (MRI) for patients with acute and chronic anterior cruciate ligament (ACL) tears.Two independent reviewers retrospectively evaluated the MRI images of 377 patients with ACL tear confirmed by arthroscopy. There were 160 cases with acute ACL tear and 217 cases with chronic ACL tear. Direct signs in T1- and T2-wighted images and indirect signs including meniscus injury, the collateral ligament injury, cartilage damage or osteoarthritis, kissing contusion, Notch syndrome and abnormal posterior cruciate ligament (PCL) and other indirect signs were evaluated.For direct signs on MRI, no significant differences were found between the acute and chronic ACL tear in prevalence of focal high signal in substance of T2-wighted images and in that of abnormal orientation, discontinuity, thickening, or focal masses in substance of T1-weighted images. However, higher incidence of diffuse high signal of T2-weighted images for acute ACL tear was found compared to that for chronic ACL tear (55.0% vs 3.2%). For indirect signs on MRI, the collateral ligament tear (20.6% vs 2.3%), cartilage damage or osteoarthritis (14.4% vs 25.8%), kissing contusion (57.4% vs 0%), Notch syndrome (28.1% vs 3.2%), and bowing type of PCL (33.1% vs 47.0%) can differentiate the acute from chronic ACL tear.Some direct and indirect signs on MRI are closely related to the acute and chronic ACL tear.

Notchplasty for the Arthroscopic Treatment of Limited Knee Extension

Knee osteoarthritis may lead to narrowing of the intercondylar notch due to osteophyte formation, thereby causing changes in native knee biomechanics. The normal close contact between the condyles and the anterior cruciate ligament (ACL) during knee extension may be compromised due to narrowing of the notch and result in ACL damage, progression of knee osteoarthritis, and loss of knee extension. Outcomes after a notchplasty procedure are well reported for ACL reconstruction in young patients. However, there remains a lack of studies evaluating this procedure in the setting of knee osteoarthritis in patients with a symptomatic loss of knee extension. The purpose of this Technical Note is to present our preferred surgical technique for the treatment of loss of knee extension in the setting of knee osteoarthritis in conjunction with osteophyte formation in the intercondylar notch.