Intercondylar Notch Becomes Steeper After Transphyseal Anterior Cruciate Ligament Reconstruction in Skeletally Immature Knees

BACKGROUND

Transphyseal anterior cruciate ligament (ACL) reconstruction can be a reliable and safe treatment for skeletally immature patients, with low reported rates of major growth disturbances. However, more subtle knee morphologic and radiologic characteristics, such as the α-angle (sagittal orientation of the notch roof) and posterior tibial slope, may theoretically be affected by this surgical technique and potentially represent risk factors for ACL graft tears. The objective of this study was to compare radiologic knee morphology characteristics between the operated knee and the paired contralateral knee in skeletally immature patients following transphyseal ACL reconstruction.

METHODS

This is a retrospective matched within-subject case-control study on 25 skeletally immature patients with a radiologic follow-up 9 or more months after a transphyseal anatomic ACL reconstruction. The α-angle, medial posterior tibial slope, mechanical hip-knee-ankle angle, and leg length were assessed with a biplane x-ray imaging system (EOS) with the nonoperative limb used as an internal control.

RESULTS

The mean chronological age of the cohort was 11.8 years (range: 8.3 to 15.0). The α-angle was a mean of 3.3 degrees (SD=5.1) smaller, or more vertical, on the surgical knee than on the contralateral knee at a median of 2.1 years [interquartile range (IQR)=0.3 to 4.0], with mean α-angles of 36.6 degrees (SD=6.6 degrees) and 39.9 degrees (SD=5.3), respectively (P=0.002). Other radiologic parameters were not significantly different between sides. A post hoc analysis showed a median side-to-side difference in α-angles of -5.0 (IQR: -7.0 to -1.9) in males versus 0.6 (IQR: -4.3 to 3.8) in females (P=0.009).

CONCLUSION

Transphyseal anatomic single-bundle ACL reconstruction in skeletally immature patients is associated with a relative decrease in α-angle, or verticalization of the notch roof, after a median follow-up of 2 years. A greater impact in α-angle was observed in male patients.

LEVEL OF EVIDENCE

Level III-prognostic case-control study.

A tight anterosuperior intercondylar notch may increase the risk of cyclops syndrome after anterior cruciate ligament reconstruction using a quadruple semi-tendinosus short autograft

BACKGROUND

Cyclops syndrome is loss of terminal knee extension caused by a fibrous nodule developed in the anterior intercondylar notch. The many known risk factors include preoperative motion-range limitation, tibial tunnel malposition, and tight hamstrings. The primary objective of this study was to assess whether intercondylar notch size was associated with the risk of cyclops syndrome or graft tear after anterior cruciate ligament (ACL) reconstruction using a quadruple semi-tendinosis autograft. The secondary objective was to determine whether intercondylar notch size was associated with functional outcomes.

HYPOTHESIS

A narrow intercondylar notch is associated with higher risks of cyclops syndrome and poor functional outcomes.

METHODS

Consecutive patients who underwent ACL reconstruction by quadruple semi-tendinosus autograft were included retrospectively. Preoperative magnetic resonance imaging scans were assessed by a single senior surgeon, who determined the conventional notch width index (NWI) and the anterior NWI (aNWI) for each patient.

RESULTS

The 120 included patients had a mean follow-up of 2.4±0.8 years. Among them, 20 (16.7%) experienced cyclops syndrome and 7 (5.8%) graft rupture. At last follow-up, 26 (21.7%) had not returned to sports and only 47 (39.2%) had returned to sports at the pre-injury level. The mean Lysholm score was 87.9±13.5 and the main subjective IKDC score was 84±13. A narrow notch was significantly associated with lower likelihoods of returning to sports (p=0.001), returning to the same sport (p<0.0001), and returning to the pre-injury sport level (p=0.004). By multivariate analysis, only the aNWI index was significantly associated with the risk of cyclops syndrome (p<0.0001). An aNWI index lower than 0.18 had 85% sensitivity and 78% specificity for predicting cyclops syndrome.

CONCLUSION

A narrow anterosuperior intercondylar notch may increase the risk of cyclops syndrome after ACL reconstruction using a quadruple semi-tendinosus graft but is not associated with the risk of graft rupture.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

A statistical shape and density model can accurately predict bone morphology and regional femoral bone mineral density variation in children

Finite element analysis (FEA) is a widely used tool to predict bone biomechanics in orthopaedics for prevention, treatment, and implant design. Subject-specific FEA models are more accurate than generic adult-scaled models, especially for a paediatric population, due to significant differences in bone geometry and bone mineral density. However, creating these models can be time-consuming, costly and requires medical imaging. To address these limitations, population-based models have been successful in characterizing bone shape and density variation in adults. However, children are not small adults and need their own population-based model to generate accurate and accessible musculoskeletal geometry and bone mineral density in a paediatric population. Therefore, this study aimed to create a biomechanical research tool to predict the personalized shape and density of the paediatric femur using a statistical shape and density model for a population of children aged from 4 to 18 years old. Femur morphology and bone mineral density were extracted from 330 CT scans of children. Variations in shape and density were captured using Principal Component Analysis (PCA). Principal components were correlated to demographic and linear bone measurements to create a predictive statistical shape-density model, which was used to predict femoral shape and density. A leave-one-out analysis showed that the shape-density model can predict the femur geometry with a root mean square error (RMSE) of 1.78 ± 0.46 mm and the bone mineral density with a normalized RMSE ranging from 8.9 % to 13.5 % across various femoral regions. These results underscore the model's potential to reflect real-world physiological variations in the paediatric femur. This statistical shape and density model has the potential for clinical application in rapidly generating personalized computational models using partial or no medical imaging data.

Evaluation of Bony Femoral Morphological Parameters in Anterior Cruciate Ligament Injury Using Magnetic Resonance Imaging: A Retrospective Unmatched Case-Control Study

Background Over time, there has been a noticeable increase in anterior cruciate ligament (ACL) injuries. The current imperative is to anticipate predisposing factors and proactively prevent ACL injuries. The occurrence of ACL injuries has been linked to diverse factors associated with the morphology of the distal femur. Objectives Through this study, we aim to compare the anatomic variables of distal femur morphology such as notch width (NW), bicondylar width (BW), notch entrance width (NEW), and notch width index (NWI) between patients with ACL injuries and non-injured patients using MRI. We also aim to make a comparison of these factors between male and female genders to assess the gender variability. Material and methods A retrospective case-control study was conducted amongst patients who underwent MRI Knee scan for clinical suspicion of internal derangement during the study period. We selected the first 125 individuals who were found to have ACL injury in the MRI scans and selected another 125 individuals who had an intact ACL in the scans, to serve as controls in the study. Demographic information was retrieved from the hospital's electronic records, and the assessment of NW, NWI, BW, and NEW was conducted through a review of MRI sequences. They were then compared between the cases and control groups, as well as between male and female genders. Results The ACL-injured group exhibited statistically significant reductions in NW and NWI. While 17.39 mm was the mean NW among cases, 17.86 was the mean value among controls. Similarly, the mean NWI was 0.25 among patients with ACL injuries and 0.27 among controls. Gender-based comparisons also revealed statistically significant differences in NW and NWI measurements, where females were reported to have comparatively lower measurements. The mean NW for males and females in the injured group were 18.26 mm and 15.40 mm, respectively, while it was 18.71 mm and 16.90 mm, respectively, in the control group. In the case of NEW, males in the injured group had a slightly higher value (21.33 mm) than the controls (20.65). Females on the other hand exhibited a lower mean value of NEW in ACL-injured group (18.51 mm) in comparison to the non-injured (18.79 mm). BW did not seem to show a significant difference between the two groups. Conclusions In the studied population, ACL injuries demonstrated a higher occurrence in individuals with a narrow femoral intercondylar NWI. If any of these characteristics are identified in an MRI, it may be helpful to identify individuals who are at a higher risk of developing ACL injuries and may thereby help in planning preventative strategies.

Magnetic Resonance Imaging-Based Morphometric Analyses of the Bicruciate Injury of the Knee: Is There a Clue in the Distal Femur?

BACKGROUND

The morphology of the distal femur's intercondylar notch has been implicated in the susceptibility to and severity of cruciate ligament injuries. While previous research has primarily focused on isolated anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) injuries, the relationship between notch morphology and combined cruciate injuries remains less understood.

OBJECTIVE

This study aimed to explore the association between femoral notch morphology and the severity of combined cruciate ligament injuries in adult males.

METHODS

In this retrospective cohort study, MRI scans from 118 adult male participants with and without knee dislocations (60 cases with Schenk classification Type II or higher knee dislocations and 58 controls) were analyzed. The study period ranged from 2015 to 2023. Femoral notch width, notch width index (NWI), and notch shape (U shape, A shape) were assessed using a Philips Multiva 1.5 Tesla system (Philips, Amsterdam, Netherlands). The statistical significance of differences in measurements between cases and controls was evaluated using independent sample t-tests performed with IBM SPSS Statistics, version 26 (IBM Corp., Armonk, NY).

RESULTS

The case group exhibited a significantly smaller mean femoral notch width (15.88 mm ± 2.7 mm) and NWI (0.238 ± 0.58) compared to the control group (notch width 18.29 mm ± 3.4 mm, NWI 0.25 ± 0.31), with p-values of 0.004 for both measurements. The notch shape was predominantly A-shaped in the case group (n = 49) as opposed to U-shaped in the control group (n = 41).

CONCLUSIONS

The study identifies a significant association between reduced femoral notch dimensions and the severity of complex cruciate ligament injuries. These findings support the notion that specific femoral notch morphologies may predispose individuals to more severe ligamentous injuries.

Sex-Specific Changes in Physical Risk Factors for Anterior Cruciate Ligament Injury by Chronological Age and Stages of Growth and Maturation From 8 to 18 Years of Age

OBJECTIVE

To critically assess the literature focused on sex-specific trajectories in physical characteristics associated with anterior cruciate ligament (ACL) injury risk by age and maturational stage.

DATA SOURCES

PubMed, CINAHL, Scopus, and SPORTDiscus databases were searched through December 2021.

STUDY SELECTION

Longitudinal and cross-sectional studies of healthy 8- to 18-year-olds, stratified by sex and age or maturation on ≥1 measure of body composition, lower extremity strength, ACL size, joint laxity, knee-joint geometry, lower extremity alignment, balance, or lower extremity biomechanics were included.

DATA EXTRACTION

Extracted data included study design, participant characteristics, maturational metrics, and outcome measures. We used random-effects meta-analyses to examine sex differences in trajectory over time. For each variable, standardized differences in means between sexes were calculated.

DATA SYNTHESIS

The search yielded 216 primary and 22 secondary articles. Less fat-free mass, leg strength, and power and greater general joint laxity were evident in girls by 8 to 10 years of age and Tanner stage I. Sex differences in body composition, strength, power, general joint laxity, and balance were more evident by 11 to 13 years of age and when transitioning from the prepubertal to pubertal stages. Sex differences in ACL size (smaller in girls), anterior knee laxity and tibiofemoral angle (greater in girls), and higher-risk biomechanics (in girls) were observed at later ages and when transitioning from the pubertal to postpubertal stages. Inconsistent study designs and data reporting limited the number of included studies.

CONCLUSIONS

Critical gaps remain in our knowledge and highlight the need to improve our understanding of the relative timing and tempo of ACL risk factor development.

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.

Analysis of intercondylar notch size and shape in patients with cyclops syndrome after anterior cruciate ligament reconstruction

Background

Cyclops lesion is the second most common cause of extension loss after anterior cruciate ligament reconstruction. This study focused on the correlation between the anatomy of the intercondylar notch and the incidence of cyclops lesion. To determine whether the size and shape of the intercondylar notch are related to cyclops lesion formation following anterior cruciate ligament reconstruction according to magnetic resonance imaging (MRI) findings.

Methods

One hundred twenty-five (125) patients were retrospectively evaluated. The notch width index (NWI) and notch shape index (NSI) were measured based on coronal and axial MRI sections in patients diagnosed with cyclops syndrome (n = 25), diagnosed with complete anterior cruciate ligament (ACL) tears (n = 50), and without cyclops lesions or ACL ruptures (n = 50).

Results

Imaging analysis results showed that the cyclops and ACL groups had lower mean NWI and NSI values than the control group. Significant between-group differences were found in NSI (p = 0.0140) based on coronal cross-sections and in NWI (p = 0.0026) and NSI (p < 0.0001) based on axial sections.

Conclusions

The geometry of the intercondylar notch was found to be associated with the risk of cyclops lesion formation and ACL rupture.

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.

Femoral Intercondylar Notch: Gross Anatomy and Histology of the Connective Tissue Lining of its Roof: A Pilot Study

PURPOSE

We have consistently observed a connective tissue lining over the intercondylar notch's roof (CTLINR) during arthroscopic surgeries of the knee joint. As there is a strong association of the intercondylar fossa with the anterior cruciate ligament (ACL), we believe that this tissue must be having some role in the functioning of the ACL. The purpose of this pilot study was to investigate the anatomic characteristics of the CTLINR.

METHODS

In this observational anatomical study, we have investigated the gross anatomical and histological features of the CTLINR in four knees of two fresh frozen non-embalmed cadavers. We have also studied its ultrastructural characteristics by obtaining an arthroscopic biopsy of the tissue from a patient undergoing ACL reconstruction.

RESULTS

At gross examination, the CTLINR had a typical glistening white surface with transversely oriented fibres. It entirely covered the roof of the intercondylar notch and was soft to touch. Histological examination with haematoxylin-eosin stain revealed fibro-collagenous tissue with intervening blood vessels. Transmission electron microscopy manifested loosely arranged collagen fibres of variable diameter.

CONCLUSION

The histological and electron microscopic characteristics of the tissue differentiate it from the ACL and its femoral enthesis, suggesting that it was a distinct anatomical structure. As it entirely covered the roof of the intercondylar fossa and had a smooth surface and soft consistency, it may protect the reconstructed ACL from graft abrasion. Furthermore, as it had a characteristic arthroscopic appearance, future research can investigate its role in femoral tunnel positioning.

The relationship of anterior cruciate ligament injuries with MRI based calculation of femoral notch width, notch width index, notch shape - A randomized control study

BACKGROUND

ACL injuries are infamously known for disability in young adults and require surgical reconstruction. The need of time is to predict predisposing factors and prevent ACL injuries.The incidence of ACL injuries has been associated with various factors related to the morphology of distal femur and proximal tibia.Hence, purpose of this study was to assess the relationship of morphology of distal femur by assessing Notch Width(NW), Notch Width Index (NWI), and Notch shape calculated preoperatively on MRI in association with an ACL tear.

METHODS

The following randomized control study had 60 patients enrolled with non contact injury to knee who were equally divided into 2 groups i.e. ACL injury group and control group. ACL group had patients who had MRI proven ACL tear along with clinical findings suggestive of ACL tear whereas control contained patients with intact ACL. Demographic data was collected and NW, NWI and Notch shape were determined on coronal sections of MRI sequences.

RESULTS

Positive correlation of ACL tear was seen with NW, BCW, NWI, NWP, and NWJ. Smaller Notch Width showed higher incidence of ACL tear (p = 0.019). The mean NWI in the injured and control knee is 0.31 ± 0.01 and 0.27 ± 0.01 respectively and was statistically significant(p < 0.001). A shaped Notch (60%) was commonly seen in ACL tear group and U shaped notch (73.3%) was commonly seen in control group.We found the cut off value for the prediction of ACL tear of NWI was 0.29 with a sensitivity of 90% and specificity of 86.7%.

CONCLUSION

ACL injuries in the given population have shown higher incidence with narrow femoral intercondylar notch, smaller notch width index, 'A' shaped femoral notch. If any of the above findings are present in the MRI, its important to counsel the subjects about the increased risk of ACL injuries in them and take preventive measures.

Sex Differences in Anatomic Features Linked to Anterior Cruciate Ligament Injuries During Skeletal Growth and Maturation

BACKGROUND

Several anatomic features of the knee have been shown to affect joint and anterior cruciate ligament (ACL) loading and the risk of subsequent injuries. While several studies have highlighted sex differences between these anatomic features, little is known on how these differences develop during skeletal growth and maturation.

HYPOTHESES

(A) Anatomic features linked to an ACL injury will significantly change during skeletal growth and maturation. (B) The age-related changes in anatomic features linked to an ACL injury are different between male and female patients.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

After institutional review board approval, magnetic resonance imaging data from 269 unique knees (patient age 3-18 years; 51% female), free from any injuries, were used to measure femoral notch width, posterior slope of the lateral tibial plateau (lateral tibial slope), medial tibial depth, tibial spine height, and posterior lateral meniscal bone angle. Linear regression was used to test the associations between age and quantified anatomic indices. Patients were then divided into 4 age groups: preschool (3-6 years), prepubertal (7-10 years), early adolescent (11-14 years), and late adolescent (15-18 years). Also, 2-way analysis of variance with the Holm-Sidak post hoc test was used to compare morphology between male and female patients in each age group.

RESULTS

The femoral notch width, medial tibial depth, and tibial spine height significantly increased with age (P < .001). The lateral tibial slope decreased with age only in male patients (P < .001). Except for the posterior lateral meniscal bone angle, the age-related changes in anatomy were different between male and female patients (P < .05). On average, early and late adolescent female patients had smaller femoral notches, steeper lateral tibial slopes, flatter medial tibial plateaus, and shorter tibial spines compared with age-matched male patients (P < .01).

CONCLUSION

Overall, the findings supported our hypotheses, showing sex-specific changes in anatomic features linked to an ACL injury during skeletal growth and maturation. These observations help to better explain the reported age and sex differences in the prevalence of ACL injuries. The fact that most of these anatomic features undergo substantial changes during skeletal growth and maturation introduces the hypothesis that prophylactic interventions (ie, activity modification) would have the potential to reshape a maturing knee in a manner that lowers the risk of noncontact ACL injuries.

The development of the intercondylar notch in the pediatric population

BACKGROUND

Anterior cruciate ligament (ACL) repair is increasing in frequency in younger children. Recognition of the normal development of the intercondylar notch is important for successful ACL graft placement, allowing surgeons to better understand the anatomy and risk factors related to ACL tears and its reconstruction. The purpose of this study was to compile normative data on the intercondylar notch in the pediatric population with magnetic resonance imaging (MRI), emphasizing the differences between males and females.

METHODS

In this retrospective study, musculoskeletal radiologists evaluated intercondylar notch width, bicondylar distance and notch width index (NWI). A total of 253 MRI examinations (130 males and 123 females between six and 18 years of age) were included. The association between measurements, sex and age was considered. Linear and fractional polynomial regression models were used to evaluate the relationships between measurements.

RESULTS

Intercondylar notch width increased up to 10 years of age in females and 11 years of age in males, with relative stabilization up to 13 years in girls and 14 years in boys and a slight reduction in values at subsequent ages. Bicondylar distance showed significant progressive growth with age in both sexes. NWI showed a discrete and homogenous reduction with age in both sexes.

CONCLUSION

Intercondylar notch width interrupts its growth around 10-11 years of age, with relative stabilization up to 13-14 years and a slight reduction in dimensions in subsequent ages. This growth pattern resembles the development of the ACL area observed in recent studies.

Intercondylar Notch Measurement During Arthroscopy and on Preoperative Magnetic Resonance Imaging

Small intercondylar notch size is associated with increased risk of anterior cruciate ligament (ACL) injuries and increased difficulty of ACL reconstruction. When encountering a small notch during surgery, some surgeons may resort to a notchplasty, which has been shown to have associated morbidity. The ability to predict notch size on preoperative imaging could allow the orthopaedic surgeon to anticipate surgical difficulty such as an oversized graft and graft impingement and possibly avoid a notchplasty. Many methods have been proposed for measuring intercondylar notch size, but they do not correlate with intraoperative measurements or they utilize computed tomography scanning, which is not readily obtained before ACL reconstruction. The purpose of this study was to develop a method of notch measurement on preoperative radiography and magnetic resonance imaging that match intraoperative arthroscopic measurements. The method presented here can be used to identify narrow intercondylar notches, prepare for potential intraoperative challenges, and formulate surgical plans such as for graft choice in individualized ACL reconstruction.

Evaluation of the age and gender related changes in the Blumensaat line

PURPOSE

The position of the patella according to the femur is very important in the evaluation of patella-femoral joint disorders. In 1938, Blumensaat (BS) described the BS line to evaluate the patella femoral congruence. This method is still valuable in clinical use. There is a limited number of studies demonstrating the accuracy of BS method as well as the affected variables. The aim of this study was to evaluate o the age and gender-related changes in the BS line.

METHODS

Standard lateral knee radiography was performed to all patients at 30° flexion. The relationship between the BS line and the patella inferior pole was examined and the variability of the measurements according to gender and age groups was investigated by statistical methods.

RESULTS

Ninety-five patients (43 men and 52 women) were enrolled in the study. Mean age of the patients were 43.7 ± 14.1 years (48.2 ± 11.7, 37.9 ± 14.8 in women and men, respectively). The BS line was passed through the inferior pole of the patella in only 2 (2.1%) of 95 patients. There was a statistically significant difference (p = 0.041) between BS measurement and gender which was found to be higher in females than males. There was no statistically significant correlation with this distance between the age groups (r = - 0.216, p = 0.427).

CONCLUSION

In our study, it was concluded that BS measurement differs according to gender but did not have any difference between different age groups.

Evaluation of Posterior Cruciate Ligament and Intercondylar Notch in Subjects With Anterior Cruciate Ligament Tear: A Comparative Flexed-Knee 3D Magnetic Resonance Imaging Study

PURPOSE

To determine if posterior cruciate ligament (PCL) and intercondylar notch (IN) morphometries and volumetrics act as risk factors for anterior cruciate ligament (ACL) tears.

METHODS

A prospective case-controlled magnetic resonance imaging (MRI) study was conducted with subjects presenting noncontact knee injuries. Exclusion criteria were previous surgery, PCL tear, osteoarthritis, tumors, or infectious and inflammatory conditions. All participants underwent a flexed-knee 3-dimensional (3D) magnetic resonance imaging (MRI) to uniformly straighten PCL. MR images were independently reviewed by 2 radiologists and assessed for 2D and 3D measurements (bicondylar width; IN angle, depth, width, and cross-sectional area; PCL width, thickness, and cross-sectional area; and IN and PCL volumes). Clinical profiles were tabulated and subjects were divided into cases (ACL tear) and controls (without ACL tear).

RESULTS

The study was composed of 50 cases versus 52 controls (N = 102), with a mean age of 36.8 years. There was no difference between groups (P > .05) regarding age, gender, body mass index, time from injury, Tegner score, flexion angle, limb side, intensity of injury, or familial or opposite limb history of tear. Agreement between readers ranged from substantial to almost perfect. Subjects with ACL tear presented with lower IN width, lower IN minus PCL widths, lower Notch Width Index, higher PCL/IN width proportion, higher PCL thickness, lower IN depth minus PCL thickness, and higher PCL thickness/IN depth proportion (P < .05). Moreover, higher PCL/IN cross-sectional area proportion, higher PCL volumes (OR = 9.01), and higher PCL/IN volume proportion were also found in cases.

CONCLUSIONS

Our study shows that subjects with ACL tears present not only reduced IN but also larger PCL dimensions. These findings, isolated and combined, and especially PCL volume, might be suggestive as risk factors for ACL tears owing to the reduction of its space inside the IN.

LEVEL OF EVIDENCE

Level III, comparative group.

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.