Sulcus Angle Research Articles

Poster 219: Posterior Sagittal Position of the Tibial Tubercle as Measured by the Sagittal Tibial Tubercle – Trochlear Groove Distance Correlates with an Increased Risk for Surgery in Patients with Patellofemoral Chondral Lesions

Objectives:The etiology of isolated patellofemoral (PF) cartilage defects without patellar instability is currently incompletely understood. The purpose of the present study was to evaluate the variation in knee sagittal alignment in patients with and without PF cartilage wear.Methods:This was a single-center, retrospective review of patients that underwent a cartilage restoration procedure for isolated PF cartilage wear from 2014-2020. Patients were matched in a 1:2:2 ratio for age, sex, and BMI to anterior knee pain diagnosis and meniscectomy procedure cohorts as controls. Exclusion criteria included knee flexion angle >10°, elevated Caton-Deschamps index (CDI>1.3), increased sulcus angle (>145°), increased patellar tilt (>5°), elevated coronal TT-TG (>15mm), varus/valgus malalignment (>5°), or ICRS patellofemoral cartilage defects of ≥3 in either control group. The sagittal TT-TG (sTT-TG) distance was measured on preoperative axial T2 magnetic resonance imaging (MRI) and was defined as the distance between a point at the nadir of the trochlear cartilage and the most anterior point of the tibial tubercle. Comparisons between the 3 groups were made using ANOVA testing with Bonferroni corrections. Reliability was assessed with the interclass correlation coefficient (ICC). Odds ratios were calculated based on a sTT-TG measurement threshold obtained from a receiver operative characteristic curve graph.Results:Two hundred and thirty-five patients (47 cartilage restoration, 94 anterior knee pain, 94 meniscectomy) were included. Mean age, BMI, and height were 33.8 +/- 8.7 and 26.7 +/- 5.7, 170.6 +/- 24.3 respectively, with 130 males (55%) and 105 females (45%). There were no significant differences between groups for age, BMI or sex(p>0.05). Mean sTT-TG was significantly more posterior in the cartilage restoration group compared to the meniscectomy group (-2.5 mm +/-5.9 vs 1.72 mm +/- 5.3, p<0.001). The anterior knee pain group sTT-TG was between the meniscectomy and cartilage restoration groups, but was not significantly different from either (p=0.067, p=0.13). Interrater reliability was excellent (ICC=0.927, p<0.001). Patients with a posterior translation of -2.15 or greater were 2.12 times more likely to undergo a cartilage restoration procedure (OR 2.12, 95% CI 1.1 to 4.1).Conclusions:Cartilage restoration procedure patients had a significantly more posterior tibial tubercle than partial meniscectomy controls. Anterior knee pain patient sagittal TT-TG was between both groups, but was not significantly different from either. Patients with sTT-TG of <-2.15 mm were 2.12 x more likely to have a cartilage restoration procedure.

Paper 51: Multiple Prior Dislocations Lead to Poorer Outcomes of Isolated Medial Patellofemoral Ligament Reconstruction: A Retrospective Chart Review

Objectives:Patellar dislocation is a common knee injury and up to 35% who dislocate can develop recurrent patellar instability. In the setting of recurrent instability, medial patellofemoral ligament reconstruction (MPFLR) often restores knee stability. There has been recent interest in the evaluation of patient and surgical factors that may influence the outcomes of isolated MPFLR. Much of the previous work has focused on influences of anatomical measures; however, patient and injury characteristics may also impact surgical outcomes. We hypothesize that patients who suffer > 2 patellar dislocations prior to MPFLR will demonstrate poorer patient-reported outcomes (PROs) than those who experience ≤ 2 prior dislocations.Methods:Records were reviewed to identify patients who underwent MPFLR at a single academic institution in the United States between 2008 and 2016. Patients were excluded if they underwent concomitant tibial tubercle osteotomy or fixation of an osteochondral fracture. Patient demographics (age, sex, BMI), number of prior patellar dislocations, and patient anatomical measures (Caton-Deschamps index, tibial tubercle-trochlear groove distance, and trochlear sulcus angle) were collected. PROs were assessed with Norwich Patellar Instability (NPI) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Marx activity score. Outcomes of those with > 2 or ≤ 2 patellar dislocations were compared using linear regression analysis.Results:A total of 160 patients were identified who underwent isolated MPFLR. Ninety-five patients (60%) were available to complete PROs at a mean follow-up of 4.8 years post-operation. Patients with < 2 dislocations were younger (≤ 2 dislocations: 20.7 ± 9.4yrs, > 2 dislocations: 27.4 ± 9.4yrs; p < 0.001), though there were no other differences between groups in terms of demographics or radiographic anatomical measures (Table 1). Controlling for age, sex, BMI, and anatomical factors linear regression analysis found that patients with > 2 dislocations had lower KOOS pain (p = 0.003), ADLs (p = 0.025), Sports/rec (p = 0.009), and knee related QOL (p = 0.008) subscales (Table 2).Conclusions:Patients who suffer > 2 patellar dislocations prior to MPFLR demonstrate poorer PROs at 4.8 years post-operation than those who suffer < 2 dislocations prior to surgery. To our knowledge, no other study has investigated the relationship between the number of pior patellar dislocations and outcomes following MPFLR. Our findings emphasize the role patient and injury factors may play in determining outcomes following MPFLR.Table 1.Comparison of patients based on number of prior dislocations controlling for age, sex, BMI, CDI, TT-TG distance, and sulcus angleTable 2.PROs for patients with ≤ 2 or > 2 patellar dislocations prior to MPFLR, controlling for age, sex, BMI, CDI, TT-TG distance, and sulcus angle

Changes in Anatomic Risk Factors for Patellar Instability During Skeletal Growth and Maturation

Background: Several anatomic risk factors have been identified in the pathogenesis of patellofemoral instability. The literature is sparce regarding how these anatomic risk factors change during skeletal growth and development. Hypothesis: The anatomic risk factors associated with patellar instability change significantly during skeletal growth and maturation with different patterns in male versus female patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Magnetic resonance imaging data from 240 unique, asymptomatic knees (7-18 years of age; 50% female) were used to measure patellar height (Caton-Deschamps index), lateral patellar tilt angle, trochlear height, trochlear groove depth, trochlear sulcus angle, and tibial tubercle–trochlear groove (TT-TG) distance. Linear regression was used to test the associations between age and anatomic findings. Two-way analysis of variance with Holm-Šídák post hoc test was used to compare anatomic characteristics between sexes in 3 age groups: prepubertal school-aged children (7-10 years old), early adolescents (11-14 years old), and late adolescents (15-18 years old). Results: Patellar height (female sex), lateral patellar tilt angle (male sex), and trochlear sulcus angle (both sexes) decreased with age (P < .001). Trochlear height, depth, and TT-TG distance increased with age in both male and female participants (P < .02). Male participants had a larger sulcus angle (by 5.3°± 1.6° at age 11-14 years) and greater trochlear height (by >5 mm across medial, central, and lateral regions at age 15-18 years) than age-matched female participants (P < .01). We found no other sex-related differences in quantified anatomic features (P > .1). Conclusion: The findings partially support our hypothesis indicating significant age-related changes in all quantified features, which were not different between male and female participants except for trochlear sulcus angle in early adolescence and trochlear height in late adolescence. In general, the majority of anatomic risk factors for patellar instability change with maturity in a direction that assists in reducing the risk of patellar instability and/or dislocation. The only outlier is the TT-TG distance, which increased by age, and in our oldest cohort of patients, the mean fell below the normal adult range. The current observations highlight the importance of age in the interpretation of risk for injury as well as the need for further studies to identify intrinsic and extrinsic factors that may result in abnormal development of these anatomic features during skeletal growth and maturation.

Computed Tomographic Measurements of the Sulcus Angle of the Femoral Trochlea in Small-Breed Dogs with and without Medial Patellar Luxation.

Trochleoplasty is often performed in dogs with medial patellar luxation (MPL); however, the current guidelines on when to perform a trochleoplasty in dogs are vague. The sulcus angle (SA) is used to assess the femoral trochlear morphology in humans. The aim of this study is to describe a method to measure the SA and other parameters of trochlea morphology in dogs using computed tomography. First, we searched for a suitable measuring location for the SA. Transverse images of the femurs were obtained as perpendicular planes to the tangent of the femoral trochlea which was 0 to 60 degrees (every 5 degrees) to the anatomical axis of the femur. The deepest point of the femoral trochlea was found in the transverse images perpendicular to the tangent of the femoral trochlea which was at 15 degrees to the anatomical axis of the femur. The SA and the other parameters of femoral trochlea morphology were measured at the deepest point of the femoral trochlea. The SA of the stifle joints with grade 3 and 4 MPL was significantly higher than the SA of stifle joints not affected by MPL. There was no significant difference in the SA between dogs affected by grade 1 and 2 MPL and dogs not affected by MPL. Further studies are needed to establish whether the SA can be used as selection criteria for trochleoplasty.

Morphological Analysis of Hip Joint of Patients Suffering From Recurrent Patella Dislocation.

The purpose was to investigate morphological changes of the hip joint in patients with recurrent dislocation of the patella combined with trochlear dysplasia. There was a retrospective analysis of 148 patients and 150 control subjects. The selection of participants was randomized. Hip and knee data for all participants were obtained from X-ray or computed tomography measurements. Nine values, that is, central edge angle (CEA), acetabulum index angle (AIA), femoral neck-shaft angle, sharp angle, the depth of the acetabulum, femoral anteversion angle (FAA), anterior acetabular section angle (AASA), posterior acetabular section angle (PASA), and sulcus angle, were measured to evaluate differences between the control group and the patient group and analyze the correlation of the sulcus angle in patients to FAA and CEA. Patients with recurrent dislocation of the patella had less acetabular coverage and are more likely to develop developmental dysplasia of the hip than the hips of patients with normal knees. For the patient group, three values, that is, CEA (27.68 ± 5.25 vs. 34.30 ± 3.51 degrees, p < 0.001), AASA (57.14 ± 6.17 vs. 63.08 ± 7.23 degrees, p < 0.001), and PASA (89.53 ± 6.51 vs. 99.63 ± 5.94 degrees, p < 0.001), were decreased. The sharp angle (43.77 ± 3.23 vs. 39.28 ± 3.19 degrees, p < 0.001), AIA (11.52 ± 4.41 vs. 3.73 ± 2.51 degrees, p < 0.001), and FAA (24.68 ± 3.44 vs. 18.49 ± 3.55 degrees, p < 0.001) were increased. The acetabulum became shallower in-depth (7.05 ± 2.18 vs. 10.45 ± 1.61 mm, p < 0.001). There was a weak correlation between the sulcus angle and CEA (r = - 0.302, p < 0.001) and FAA (r = 0.212, p = 0.022). Recurrent patellar dislocation combined with trochlear dysplasia may be associated with the hip morphology. Developmental disorders of the knee joint, and hip joint should be considered in the treatment of patients with recurrent dislocation of the patella.

Radiologic Predictors of Failure of Patellofemoral Instability Surgery in Adolescents

Background:Adolescents often benefit from surgical management of recurrent patellofemoral instability (PFI). However, the precise radiologic risk factors for failure of PFI surgery remains incompletely investigated.Hypothesis/Purpose:The purpose of this study was to determine the rate of failure, defined as recurrence of instability, in a large cohort of adolescent athletes undergoing primary surgery for PFI, and to identify preoperative radiologic risk factors for recurrence.Methods:A retrospective review was performed on patients aged ≤19 years who underwent primary surgery for PFI at a single tertiary care center between 2008 and 2017. Patients underwent procedures including medial retinacular plication/reefing/advancement (MRP), medial patellofemoral ligament reconstruction (MPFLR), tibial tubercle osteotomy with or without MRP (TTO), or combined TTO/MPFLR. Exclusion criteria were BMI >30kg/m2, surgery for fixation of chondral fractures >1cm, and diagnosis of a syndromic disorder. Preoperative magnetic resonance imaging (MRI) studies were reviewed, and radiologic parameters were recorded. Demographic and radiologic variables were compared between patients with and without subsequent PFI. Logistic regression was utilized to determine which imaging variables were associated with post-operative PFI.Results:303 patients (mean age 15.1 years, 71% female) underwent surgery for PFI with median follow up time of 3.0 years. At final follow-up, 76/303 (25%) of patients experienced post-operative PFI, with 41 of these patients (54%; 14% overall) undergoing revision PFI surgery. Post-operative PFI patients were younger (14.3 vs 15.4 years; p<0.001) and more likely to have undergone isolated MRP surgery (66% vs 35%; p<0.001) (Table 1). Pertinent radiologic findings in recurrent PFI patients vs non-recurrence patients included open physes (62% vs 49%; p<0.001), larger sulcus angle (163.9 vs 159.2; p<0.001), larger patellar tilt angle (26.3 vs 23.6; p=0.04), and larger Caton-Deschamps Index (CDI) (1.3 vs 1.2; p=0.03) (Table 2). Each additional degree of sulcus angle increased the odds of recurrent instability by 5% (OR=1.05; p=0.002), while each additional year of age decreased the odds of failure by 23% (OR=0.77; p<0.001).Conclusion:In conclusion, 25% of adolescents experienced post-operative PFI after primary patellofemoral stabilization surgery. However, such patients were more likely to be younger—a known risk factor for recurrence—and were more likely to undergo MRP, a procedure now largely replaced by MPFLR. Radiologic risk factors for failure included open physes, flatter trochlea, greater patellar tilt, and greater patella alta. Such data should guide treatment decisions and inform the risk of failure of surgical stabilization procedures in adolescents with PFI.Table 1.Patient Demographics by Presence or Absence of Recurrent Instability (N=303).Table 2.Imaging Measurements by Presence or Absence of Recurrent Instability (N=303).

Osseous and Cartilaginous Trochlear Morphology in Pediatric Patients From 2 Months to 11 Years of Age: a Descriptive Analysis Based on Computed Tomography Scanning

Background:The anatomy of the trochlea plays a significant role in patella stability. Surgical approaches to alter the anatomy of the trochlea and associated structures to influence patella tracking continue to evolve. Unlike the development of the pediatric hip joint which has been well studies for decades, the developmental anatomy of the trochlea and its relationship to patella stability remains poorly understood. An improved understanding of trochlear growth and development may alter both the timing and type of surgical procedures for patella stability.Purpose:The purpose of this study was to describe the developmental changes of the osseous and cartilage trochlear morphology in skeletally immature specimens.Methods:Fifty-five skeletally immature cadaveric knees between the ages of 2 months and 11 years were evaluated using 0.625mm computed tomography scans. In the axial plane, measurements included medial and lateral osseous condylar height, medial and lateral cartilaginous condylar height, osseous and cartilaginous sulcus angles, osseous and cartilaginous condylar height asymmetry, and trochlear depth.Results:Analysis of trochlear morphology using osseous and cartilaginous measurements of condylar height, condylar height asymmetry, and trochlear depth demonstrated an increase in the size of the medial and lateral trochlea as age increased. The osseous and cartilaginous sulcus angles decreased (became deeper) with age until around age 8 and then plateaued. This corresponded with an increase in trochlear depth that plateaued also around age 8. In contrast, medial and lateral condylar height continued to increase through age 11. Cartilaginous condylar asymmetry rose slightly with age with the lateral condyle consistently larger than the medial condyle. Osseous condylar asymmetry increased with age but flipped from a larger medial condyle to a larger lateral condyle around age 8.Conclusions:This cadaveric analysis demonstrated that there is an increase in the medial and lateral trochlear height as age increased by all measurements analyzed. These changes in height continue to be seen through age 11 suggesting a still developing trochlea past this age. By age 8, a plateau in sulcus angle and sulcus depth suggests more proportionate growth after this point. Access to pediatric cadaveric specimens is exceptionally rare. This study provides a unique evaluate of the developing trochlea in young children, especially those under age 7, who rarely receive advanced imaging.Figure 1.The mean medial and lateral osseous trochlear height are identified with respect to age.Figure 2.The mean osseous and cartilaginous depth are identified with respect to age.

Changes in Patellofemoral Joint Morphology During Skeletal Growth and Maturation are not Sex-Dependent

Background:Patellofemoral disorders account for approximately 25% of patients seen in sports medicine clinics. A variety of anatomic risk factors have been identified in the pathogenesis of patellofemoral instability. While studies have analyzed these factors in adults, or compared them between healthy controls and patients with patellar injuries, little is known about how these anatomic markers change during skeletal growth and development.Hypothesis/Purpose:(A) The anatomic risk factors associated with patellar instability and dislocation change significantly during skeletal maturation. (B) These age-related changes during maturation will differ between male and female patients.Methods:After institutional review board approval, magnetic resonance imaging data from 239 unique knees (patient age 7-18; 55% female), without previous or current injury, were randomly selected and used to measure patellar height, lateral patellar tilt angle, trochlear width, trochlear depth, trochlear sulcus angle, and tibial tubercle trochlear groove distance. Linear regression was used to test the associations between age and anatomic measurement indices. Subsequently, patients were divided into four age groups: pre-pubertal school-aged children (7-10 years old), early adolescents (11-14 years old), and late adolescents (15-18 years old). Additionally, two-way analysis of variance with the Holm-Sidak post hoc test was used to compare anatomic morphologies between male and female patients in each age group.Results:Patellar height (Caton-Deschamps index), lateral patellar tilt angle and trochlear sulcus angle all decreased significantly with age (P<0.001). Trochlear width, depth, and tibial tubercule trochlear groove distance all increased significantly with age (P<0.001). Except for trochlear width in late adolescence (P<0.001) where males had wider trochlea (medial and lateral) compared to matched females, the age-related anatomic changes were similar between males and females (P>0.1).Conclusion:The findings partially support our hypothesis, as we observed significant age-related changes in all quantified anatomical indices, which was not different (except trochlear width in late adolescence) between males and females. The lack of significant differences in key morphological features of the patellofemoral joint that are linked to patellar dislocation between females and males is consistent with a similar prevalence of this injury between the two. However, the findings suggest that there are significant differences in the trochlear width between females and males at later stages of growth and maturation. The current observations suggest that these anatomic risk factors undergo significant changes during skeletal growth, providing us with a window of opportunity to use prophylactic interventions to prevent or minimize the development of high-risk morphology.Figure 1.1.CDI: Caton-Deschamps Index; TD: Trochlear Depth; TSA: Trochlear Sulcus Angle; LPTA: Lateral Patellar Tilt Angle TTTG: Tibial Tubercle Trochlear Groove Distance.Figure 1.2.Age- and sex-dependent changes in patellofemoral joint morphology during skeletal growth and maturation. Data are presented as mean and SEM (* P<0.05).

The association between patellofemoral alignment and osteoarthritis in magnetic resonance imaging.

ObjectivesOsteoarthritis (OA) is the most common joint disease in the world, becoming more prevalent with increasing age, and causes a significant burden on individuals and society. So far, several factors have been identified in association with OA of the knee joint. Age is the most crucial uncontrollable risk factor for OA. There are conflicting results regarding the relationship between patellofemoral joint orientation and OA. This study aims to elucidate the relationship between patellofemoral joint alignment and OA evidence.Material and methodsA total of 277 MRIs performed at Imam Reza Hospital during the first half of 2017 were included. Patients were divided into two groups, under 50 years old and over 50 years old. Femoral sulcus angle (SA) and depth (SD), lateral patellar displacement (LPD), tibial tubercle-trochlear groove (TTTG), lateral patellofemoral angle (LPFA), and Insall-Salvati index were measured in axial and sagittal images. The morphology of the patellofemoral articular cartilage was evaluated and the grade of joint damage was determined. P-value < 0.05 was considered as significant.ResultsSignificant correlations between SA (p-value = 0.01), SD (p-value < 0.001), Insall-Salvati index (p-value < 0.001), LPD (p-value = 0.02) values and OA in patients less than 50 years old were observed. A weak correlation was observed between SD and Insall-Salvati index values with increasing grade of articular cartilage damage (r = 0.21 and r = 0.21, respectively).ConclusionsPatellofemoral joint asymmetry in the younger people was significantly associated with joint cartilage damage and premature patellofemoral joint OA. Joint misalignment by stressing the articular cartilage causes joint cartilage changes that may be congenital or due to bone injuries such as trauma and surgery.

Can Traditional Straight-leg Swaddling Influence Developmental Dysplasia of the Femoral Trochlea? An In Vivo Study in Rats.

It has been reported that trochlear dysplasia occurs very early in development, and environmental factors like swaddling may cause developmental dysplasia of the hip, which is associated with a shallower trochlear groove. However, to our knowledge, there are no definitive studies about the relationship between trochlear dysplasia and traditional straight-leg swaddling. Using a rat model of femoral trochlear dysplasia, we asked: Does straight-leg swaddling for 1 and 2 weeks in newborn Wistar rats alter the femoral trochlea with respect to (1) gross morphology, (2) histologic appearance, as well as (3) trochlear sulcus angle, width, and depth? Eighty-four newborn Wistar rats (44 females and 40 males) were divided into two equal groups: 42 in the unswaddled group and 42 in the swaddled group; each group was comprised of 22 females and 20 males. In the swaddled group, the rats were wrapped in surgical tape to maintain hip and knee extension to simulate traditional human straight-leg swaddling. To determine whether longer periods of swaddling were associated with more severe trochlear dysplasia, 21 rats in each group were euthanized at 1 and 2 weeks, respectively, and the gross morphology of the femoral trochlea was observed by one observer blinded to condition. Then hematoxylin and eosin staining of the femoral trochlea was performed and the distribution and number of the chondrocytes of the trochlear groove were viewed through a microscope. The trochlear sulcus angles, depth, and width were measured by an experienced technician blinded to condition. By observing the gross morphology, we found that the trochlear groove in the swaddled group became qualitatively flatter compared with the unswaddled group at 1 week, and at 2 weeks, the trochlear groove became much shallower. At 1 and 2 weeks, histologic examinations showed obvious qualitative changes in the distribution and number of chondrocytes of the trochlear groove in the swaddled than in the unswaddled groups. In the swaddled group, trochlear dysplasia was more common at 2 weeks, occurring in 62% (26 of 42 [16 of 22 females and 10 of 22 males]) versus 33% (14 of 42 [8 of 22 females and 6 of 20 males]) at 1 week. At 1 week, the swaddled group showed more trochlear dysplasia compared with the unswaddled group as measured by angle of the trochlear groove (137° ± 6° versus 132°± 3.6°, mean difference 5° [95% confidence interval 2.9° to 7.2°]; p < 0.001), depth of the trochlear grove (0.28 ± 0.04 mm versus 0.31 ± 0.02 mm, mean difference 0.03 mm [95% CI 0.01 to 0.04]; p < 0.001). At 2 weeks, the swaddled group showed more severe trochlear dysplasia than at 1 week compared with the unswaddled group as measured by the angle of the trochlear groove (135° ± 6.0° versus 128° ± 4.8°, mean difference 7° [95% CI 5.7° to 10.4°]; p < 0.001), depth of the trochlear grove (0.32 ± 0.04 mm versus 0.36 ± 0.02 mm, mean difference 0.04 mm [95% CI 0.03 to 0.06]; p < 0.001). There was no difference in the width of the trochlear sulcus between the swaddled and the unswaddled groups at 1 week (1.29 ± 0.14 mm versus 1.30 ± 0.12 mm, mean difference 0.01 mm [95% CI -0.05 to 0.07]; p = 0.73) and 2 weeks (1.55 ± 0.12 mm versus 1.56 ± 0.12 mm, mean difference 0.01 mm [95% CI -0.05 to 0.07]; p = 0.70). Our results indicate that traditional straight-leg swaddling could induce trochlear dysplasia in this model of newborn rats. With an increased swaddling time of 2 weeks, more severe trochlear dysplasia appeared in the swaddled group. Our findings suggest that traditional straight-leg swaddling may impair trochlear development in the human neonate and lead to trochlear dysplasia in infants. We believe our animal model will be useful in future work to observe and study the change of cartilage and subchondral bone in each stage of the development of trochlear dysplasia and the change of mechanotransduction-associated proteins (such as, TRPV4/ Piezo1 and CollagenⅡ) in cartilage and subchondral osteocytes. It will also be helpful to further investigate the mechanism of developmental femoral trochlea dysplasia caused by biomechanical changes.

Characteristics of the patellofemoral joint of patients with DDH and the effects of Bernese periacetabular osteotomy on the patellofemoral joint

BackgroundSome patients with developmental dysplasia of the hip (DDH) complained of anterior knee pain (AKP) before and after Bernese periacetabular osteotomy (PAO) surgery. The purpose of this study was to (1) identify the characteristics of patellofemoral joint (PFJ) deformities in patients with DDH and (2) to determine the effects of PAO on the PFJ.MethodsSeventy patients (86 hips) were included in the DDH group. Thirty-three patients (33 knees) without AKP and hip pain were included in the control group. All patients underwent simultaneous CT scans of the hip and knee joints before PAO and after hardware removal surgery. The distance from the anterior inferior iliac spine to the ilioischial line (DAI), was measured in DDH patients. Imaging parameters of knees, including the sulcus angle (SA), femoral trochlear depth (FTD), patellar width (PW), tibial tuberosity-trochlear groove (TT-TG), patellar tilt angle (PTA) and lateral shift of the patella (LSP) were measured in patients in both the DDH and control group. TT-TG, PTA, and LSP of DDH patients were measured before PAO and after hardware removal. The DAI, PTA, LSP and TT-TG of all DDH patients before and after Bernese PAO were compared using paired t-tests. The FTD, PW, and SA of the DDH patients and the control group were analyzed using independent t-tests. PTA, TT-TG, and LSP between the control group and preoperative DDH patients, between the control group and post PAO patients were compared using independent t-tests.ResultsThe DAI changed from 4.04 ± 0.61 mm before PAO surgery to 5.44 ± 0.63 mm after PAO surgery. The SA of the DDH group (140.69 ± 11.30 degree) was greater than that of the control group (130.82 ± 6.43 degree). The FTD and the PW of the DDH group (5.45 ± 1.59 mm, 4.16 ± 0.36 mm) were smaller than that of the control group (7.39 ± 1.20 mm, 4.24 ± 0.38 mm). The changes in LSP, PTA, and TT-TG before and after surgery were not statistically significant. Both before and after PAO, there was no statistically significant difference in the parameters of LSP, PTA, and TT-TG compared with the control group.ConclusionThe knee joints of DDH patients presented a certain degree of femur trochlear groove dysplasia and patellofemoral instability. PAO surgery did not change PFJ stability, although the origination point of the rectus femoris muscle moved laterally during PAO surgery.

Many Radiographic and Magnetic Resonance Imaging Assessments for Surgical Decision Making in Pediatric Patellofemoral Instability Patients Demonstrate Poor Interrater Reliability

To evaluate the interrater reliability of several common radiologic parameters used for patellofemoral instability and to attempt to improve reliability for measurements demonstrating unacceptable interrater reliability through consensus training. Fifty patients with patellar instability between the ages of 10 and 19 years were selected from a prospectively enrolled cohort. For measurements demonstrating unacceptable interrater reliability (intraclass correlation coefficient [ICC]: <0.6), raters discussed consensus methods to improve reliability and re-examined a subset of 20 images from the previous set of images. If reliability was still low after the second round of assessment, the measure was considered unreliable. Of the 50 included subjects, 22 (44%) were male and the mean age at the time of imaging was 14 ± 2 years. With 1 or fewer consensus training sessions, the interrater reliability of the following radiograph indices were found to be reliable: trochlea crossing sign (ICC: 0.625), congruence angle (ICC: 0.768), Caton-Deshamps index (ICC: 0.644), lateral patellofemoral angle (ICC: 0.768), and mechanical axis deviation on hip-to-ankle alignment radiographs (ICC: 0.665-0.777). Reliable magnetic resonance imaging (MRI) indices were trochlear depth (ICC: 0.743), trochlear bump (ICC: 0.861), sulcus angle (ICC: 0.684), patellar tilt (ICC: 0.841), tibial tubercle to trochlear groove distance (ICC: 0.706), effusion (ICC: 0.866), and bone marrow edema (ICC: 0.961). With 1 or fewer consensus training sessions, the interrater reliability of the following patellofemoral indices were found to be reliable for trochlear morphology: trochlea crossing sign and congruence angle on radiograph and trochlear depth, trochlear bump, and sulcus angle on MRI. Reliable patellar position measurements included: Caton-Deshamps index and lateral patellofemoral angle on radiograph and patellar tilt and tibial tubercle to trochlear groove distance on MRI. Additional global measurements (e.g., mechanical axis deviation on standing radiographs) and MRI assessments demonstrated acceptable reliability. II, prospective diagnostic study.

Patellar Height Correlates Modestly With Trochlear Dysplasia: A Magnetic Resonance Imaging Analysis

PurposeTo evaluate whether there is a correlation between the position of the patella and trochlear morphology in patients with and without patellar instability using exclusively MRI measurements.MethodsMRI scans of knees in patients with patellofemoral instability and knees of patients with an ACL (anterior cruciate ligament) tear as a control group were reviewed. Measurements of patellar position (Canton-Deschamps ratio, Patellar Trochlear Index, and lateral patellar inclination) and trochlear morphology (lateral trochlear inclination and sulcus angle) were obtained from each scan. Bivariate and multivariate analysis was performed to identify correlations between study group, demographics, and patellofemoral joint measurements.ResultsThere were 70 knees in the patellofemoral instability group and 60 knees in the control group. Bivariate analysis showed a significant difference in all measurements between the patellar instability group and the control group. Multivariate analysis showed modest correlations between patellar position and trochlear morphology. The Caton-Deschamps (CD) ratio correlated with patellar trochlear index (P < .001) and lateral trochlear inclination (P < .001). The respective R-square goodness of fit was 41.1%. Patellar trochlear index correlated with CD ratio (P < .001), lateral trochlear inclination (P < .001), lateral patellar inclination (P < .001), and patellar instability group (P = .011). The R-sq goodness of fit was 37.3%. Lateral patellar inclination correlated with patellar trochlear index (P < .001), Lateral trochlear inclination (P < .001), and age at first dislocation or injury (P = .02). The R-sq goodness of fit was 68.56%.ConclusionsUsing MRI-based measurements of the patellofemoral joint, we identified modest, but significant, correlations between measures of patellar height (patellar trochlear index, CD ratio, and lateral patellar inclination) and trochlear dysplasia. This correlation is unclear and is likely multifactorial, but on the basis of this work, a causal relationship between trochlear dysplasia and patella alta cannot be established.Clinical RelevanceRadiographic evaluation of the patella and how it relates to the surrounding boney anatomy provides important information regarding our understanding of patella instability and its treatment.

Radiological evaluation of patellofemoral instability and possible causes of assessment errors.

Patellofemoral instability (PI) is the disruption of the patella’s relationship with the trochlear groove as a result of abnormal movement of the patella. To identify the presence of PI, conventional radiographs (anteroposterior, lateral, and axial or skyline views), magnetic resonance imaging, and computed tomography are used. In this study, we examined four main instability factors: Trochlear dysplasia, patella alta, tibial tuberosity–trochlear groove distance, and patellar tilt. We also briefly review some of the other assessment methods used in the quantitative and qualitative assessment of the patellofemoral joint, such as patellar size and shape, lateral trochlear inclination, trochlear depth, trochlear angle, and sulcus angle, in cases of PI. In addition, we reviewed the evaluation of coronal alignment, femoral anteversion, and tibial torsion. Possible causes of error that can be made when evaluating these factors are examined. PI is a multi-factorial problem. Many problems affecting bone structure and muscles morphologically and functionally can cause this condition. It is necessary to understand normal anatomy and biomechanics to make more accurate radiological measurements and to identify causes. Knowing the possible causes of measurement errors that may occur during radiological measurements and avoiding these pitfalls can provide a more reliable road map for treatment. This determines whether the disease will be treated medically and with rehabilitation or surgery without causing further complications.

Predictors of Occult Chondral Injury Sustained After a Primary Patellar Dislocation.

Background and objectivePrimary patellar dislocations can concomitantly involve osteochondral injuries for which prompt recognition is paramount for joint preservation. These injuries can be missed on radiographs, necessitating MRI examinations. In this study, we aimed to identify patient parameters that correlate with occult osteochondral injuries.MethodsPatients were retrospectively identified between 2015 and 2020 through a chart review. The inclusion criteria were as follows: patients diagnosed with a primary patellar dislocation with three radiographic views and an MRI of the injured knee. Demographic and radiographic data were evaluated.ResultsA total of 61 patients met the inclusion criteria. There were no statistically significant demographic differences between patients with osteochondral injuries and those without (p>0.05). Seven knees (88%) with an osteochondral lesion and 20 (38%) without had an effusion (p=0.02). There was no association in terms of ligamentous laxity (p=0.49), Caton-Deschamps index (CDI) (p=0.68), sulcus angle (SA) (p=0.68), congruence angle (CA) (p=0.56), and lateral patellofemoral angle (LPFA) (p=0.25) between patients with and without an occult osteochondral injury.ConclusionAmong the parameter examined, the presence of an effusion was the only one that correlated with the presence of occult osteochondral injury in our cohort.

Hippocampal Malrotation Could Be Less Significant in Epilepsy Caused by Focal Cortical Dysplasia Type I and Type II.

ObjectivesDebates over the relationship between hippocampal malrotation (HIMAL) and epilepsy continue without consensus. This study explores the role of HIMAL in a cohort of epilepsy caused by focal cortical dysplasia (FCD).MethodsIn this study, 90 patients with epilepsy caused by FCD type I and type II and 48 healthy adults underwent a 3 Tesla MRI following a dedicated epilepsy protocol for the analysis of the prevalence and morphologic features of HIMAL. In addition, numerous clinical characteristics and hippocampal volumes were evaluated.ResultsThe cohort included a total of 90 patients (32 were HIMAL, 58 were non-HIMAL). Among these patients, 32 (35.6%) had HIMAL (22 left, four right, and six bilateral), which did not differ from the 48 controls, where 16 (33.3%) had HIMAL (12 left, two right, and two bilateral). Neither the quantitative features of HIMAL (diameter ratio, dominant inferior temporal sulcus height ratio, medial distance ratio, dominant inferior temporal sulcus angle, and parahippocampal angle), nor the accompanying characteristics of HIMAL (vertical dominant inferior temporal sulcus, enlarged temporal horn, and a low position of ipsilateral fornix) showed differences between patients with FCD and controls. No statistical difference in the clinical characteristics between FCD patients with HIMAL and those without was found. Neither the side nor the existence of HIMAL was correlated with the lateralization and location of FCD. As to the hippocampal volume, there was no difference between FCD patients with HIMAL and those without.ConclusionHippocampal malrotation is a common morphologic variant in healthy controls as well as in patients with epilepsy caused by FCD type I and type II. Hippocampal malrotation could be less significant in epilepsy caused by FCD type I and type II.

High Rates of Damage to the Medial Patellofemoral Ligament, Lateral Trochlea, and Patellar Crest After Acute Patellar Dislocation: Magnetic Resonance Imaging Analysis

The primary outcome of interest of this study was to determine the frequency, location, and extent of chondral injuries and medial patellofemoral ligament (MPFL) tears, along with the rate of loose bodies, in the knee after acute primary patellar dislocation. The secondary outcome of interest was to conduct a multivariate analysis to investigate whether the presence of pathoanatomic abnormalities, including structural differences in the knees of the patients, is associated with the features of the lesions. Patients who underwent magnetic resonance imaging after primary acute patellar dislocation were identified from our institutional databases. We analyzed a total of 175 magnetic resonance imaging scans of patients aged between 14 and 25 years who were eligible for inclusion. Chondral damage to the medial facet of the patella was present in 36 patients; patellar crest, 78 patients; and lateral patellar facet, 28 patients. One patient presented with chondral defects in the medial trochlear facet, whereas 118 patients showed chondral defects in the lateral trochlear facet. Loose bodies were present in 142 patients. A total of 161 patients (92%) showed MPFL damage. The patellar portion was affected in 119 patients. Of the patients, 28 showed a partially damaged MPFL (<50%), 42 showed MPFL damage greater than 50%, and 49 presented with a complete tear of the MPFL. MPFL lesions were observed on the femoral side in 42 patients. Fourteen patients presented with an avulsion fracture on the patellar side; 28 patients, on the femoral side. The MPFL was injured in 92% of 175 patients after a first-time acute patellar dislocation. Chondral damage was most frequent at the patellar crest, followed by the lateral femoral epicondyle. No association was found between patella alta, the sulcus angle, the Q angle, the tibial tubercle-trochlear groove distance, trochlear and patellar dysplasia, and soft-tissue damage. Level IV, retrospective cohort study.

Comparison of soft tissue changes between incisor tipping and translation after premolar extraction.

ObjectiveThis study compared soft tissue changes after extraction of the four premolars followed by maximum retraction of the anterior teeth according to the type of anterior teeth movement tipping and translation.MethodsPatients who had undergone orthodontic treatment involving the extraction of four premolars were retrospectively selected and divided into either the tipping (n = 27) or translation (n = 26) groups based on the retraction of the incisor root apex and the axis changes of the incisors during the treatment period. Lateral pre- and post-treatment cephalograms were analyzed.ResultsThere were no significant differences between the tipping and translation groups before treatment. The retraction amounts of the root apex of the upper and lower incisors in the tipping group were 0.33 and 0.26 mm, respectively, and 5.02 and 5.31 mm, respectively, in the translation group (p < 0.001). The posterior movements of soft tissue points A and B in the tipping group were 0.61 and 1.25 mm, respectively, and 1.10 and 3.25 mm, respectively, in the translation group (p < 0.01). The mentolabial sulcus angle increased by 5.89° in the tipping group, whereas it decreased by 8.13° in the translation group (p < 0.001).ConclusionsAn increased amount of retraction of the incisor root apex led to the increased posterior movement of soft tissue points A and B, and this appeared more distinct in cases involving the lower incisor and lower lip.

Patellar shape is associated with femoral trochlear morphology in individuals with mature skeletal development

BackgroundAs several studies have detected correlations between patellar and femoral trochlear development, this raises the question of whether patellar shape is associated with trochlear developmental outcomes.MethodsPatellar shape and femoral trochlear morphology were retrospectively analyzed in 183 subjects, of whom 61 each were classified as having Wiberg type I, II, and III patellae (groups A, B, and C, respectively). The sulcus angle (SA), lateral trochlea inclination angle (LTA), medial trochlear inclination angle (MTA), lateral facet length (LFL), medial facet length (MFL), lateral trochlear height (LTH), medial trochlear height (MTH), trochlea sulcus height (TH), and lateral-medial trochlear facet distance (TD) were analyzed as a means of evaluating trochlear morphology. Trochlear depth, trochlear condyle asymmetry, and trochlear facet asymmetry were additionally calculated, and differences in trochlear morphology and correlations between trochlear morphology and patellar shape were evaluated.ResultsThe femoral trochlear parameters of patients in group A differed significantly from those of patients in groups B and C. No significant differences between groups B and C were evident. Patellar shape was positively correlated with LTA, MTA, MFL, trochlear condyle asymmetry, and trochlear facet asymmetry, and was negatively correlated with SA.ConclusionsThese data indicated that patellar shape and trochlear morphology are related to one another,which suggest normalized patella morphology surgery and trochlear surgery are better choices for patients with patella instability.Trial registrationRetrospectively registered.

What is the relationship between the breech presentation and femoral trochlear dysplasia? An experimental study of the breech presentation model in neonatal rats

BackgroundThe relationship between breech presentation and trochlear dysplasia has been confirmed. However, the pathological process of breech-related trochlear dysplasia remains unclear. This study aimed to establish an animal model to simulate breech presentation and to analyze the pathological process of the femoral trochlea.Materials and MethodsOne hundred and twenty neonatal rats were randomly assigned into a control group and two experimental groups that were swaddled (using surgical tape) to keep the hip flexed and knees extended to simulate human breech presentation for the 5 days (short Swaddling) and the 10 days (prolonged Swaddling) of life. Gross and cross-sectional observation, histological staining measurement in two experimental time points (5 and 10 days after birth) were conducted to evaluate the morphological changes of the femoral trochlea.ResultsThe incidence of trochlear dysplasia increased with the Swaddling time. Rats in the prolonged Swaddling group had the high prevalence of trochlea dysplasia (52 of 60), followed by short Swaddling group (42 of 60). Gross and cross-sectional observation showed a shallower trochlea groove in two experimental groups. Histologicalstaining measurement indicated that the trochlear sulcus angle and trochlear sulcus depth were significantly different between the experimental group and the control group since day 5 and day 10.ConclusionIn this model, breech presentation had an adverse effect on neonatal knees and could induce trochlear dysplasia. In addition, this study also showed that the more time in breech presentation, the more incidence of trochlear dysplasia.