Trochlear Depth Research Articles

Femoral Troklear Morfoloji: MRG ile Cinsiyet ve Bilateral Karşılaştırmalı Çalışma

Objective: The sulcus angle and trochlear depth have been widely used in the literature as a measure of trochlear morphology. The purpose of our study was to assess gender-based anatomical differences of the femoral trochlea using magnetic resonance imaging (MRI).Materials and Methods: A total of 100 patients (50 women, 50 men) were included in our study. All patients had both their knees analyzed; trochlear morphology was measured using trochlear depth, and the femoral sulcus angle on axial MR images.Results: The mean trochlear depths in the men and women were 9.1 ± 1.5 mm and 6.9 ± 1.4 mm, and the mean femoral sulcus angles in the men and women were 127 ± 9.3° and 134.7 ± 8.6°, respectively. Using MRI, no statistically significant differences were found between the right and left knees. Conclusion: This study demonstrates significant gender differences in trochlear morphology. The trochlear groove is significantly less deep and shallower amongst women than in men.

Lateral patellar maltracking due to trochlear dysplasia: A computational study

BackgroundThe study focuses on the influence of trochlear dysplasia on patellar tracking related to patellar instability. MethodsKnee extension against gravity and dual-limb squatting were simulated with seven models representing knees being treated for recurrent instability. Trochlear depth was altered to represent lateral trochlear inclination (LTI) values of 6°, 12° and 24°. Repeated measures analyses compared patellar lateral shift (bisect offset index) across different LTI values. Peak bisect offset index during extension and squatting was correlated with patella alta (Caton–Deschamps index) and maximum lateral position of the tibial tuberosity. ResultsBisect offset index varied significantly (p < 0.05) between different LTI values at multiple flexion angles throughout simulated knee extension and squatting. Average bisect offset values were 1.02, 0.95, and 0.86 for LTI = 6°, 12°, and 24°, respectively, at 0° of flexion for knee extension. The strongest correlation occurred between peak bisect offset index and lateral position of the tibial tuberosity for knee squatting with LTI = 6° (r2 = 0.81, p = 0.006). The strength of the correlation decreased as LTI increased. Caton–Deschamps was only significantly correlated with patellar tracking for LTI = 24° during knee squatting. ConclusionsA shallow trochlear groove increases lateral patellar maltracking. A lateral tibial tuberosity in combination with trochlear dysplasia increases lateral patellar tracking and the risk of patellar instability. Patella alta has relatively little influence on patellar tracking in combination with trochlear dysplasia due to the limited articular constraint provided by the trochlear groove.

Inter-rater reliability of TT-TG distance is good and does not vary based on preselected versus independent slice selection on MRI

ObjectivesPatellar instability is a frequent cause of knee dysfunction in young, active patients. Tibial tubercle–trochlear groove (TT-TG) distance, trochlear morphology (trochlear depth and sulcus angle) and patellar height are felt to contribute to patellar instability and may influence treatment. These measurements are frequently performed on MRI images. We hypothesised that inter-rater reliability of measures would be good and that inter-rater variation is driven primarily by slice selection.MethodsTwenty-six patients with at least one documented episode of patellar instability confirmed by MRI were identified. Six raters reviewed MRI images from each patient. Each rater measured and recorded TT-TG distance, trochlear depth and sulcus angle, and patellotrochlear index (PTI) for each patient and the slices used for the measurements. Each rater repeated the measurement using preselected slices. Inter-rater reliability was calculated by intraclass correlations (ICCs) for slice selection and for TT-TG distance, trochlear morphology measures and PTI with both independently selected and preselected slices. Statistically significant differences (p<0.05) in ICC based on slice selection were defined as values without overlap of their 95% CIs.ResultsInter-rater reliability was excellent for tibial (ICC=0.93) axial slice selection and sagittal slice selection (ICC=0.94), and good for femoral (ICC=0.88) axial slice selection. Using independent slice selection, inter-rater reliability was good for TT-TG distance (ICC=0.79) and fair for trochlear depth (ICC=0.57), sulcus angle (ICC=0.57) and PTI (ICC=0.71). When preselected slices were used, inter-rater reliability was good for TT-TG distance (ICC=0.85), sulcus angle (ICC=0.83) and PTI (ICC=0.77) and fair for trochlear depth (ICC=0.68). Only sulcus angle demonstrated a significant (p<0.05) improvement in inter-rater reliability with the use of preselected slices.Discussion and conclusionInter-rater reliability of TT-TG distance is good and does not vary based on preselected versus independent slice selection on MRI. Inter-rater reliability of trochlear morphology measures based on axial MRI slices and PTI is fair. Inter-rater variation can be reduced (particularly in the case of sulcus angle) through agreement on slice selection.Level of evidenceLevel III, diagnostic.

Anteroposterior distance between the tibial tuberosity and trochlear groove in patients with patellar instability

BackgroundOur objective was to describe a measurement to assess sagittal tibial tuberosity (TT)–trochlear groove (TG) distance and to compare this between asymptomatic (control) patients and patients with symptomatic patellar instability. MethodsWe compared static CT images of 22 fully extended knees of patients with symptomatic patellar instability with images of 22 asymptomatic knees. TT–TG distance was measured to quantify lateralization of the TT, and anteroposterior TT–TG distance was used to quantify the sagittal distance between these two points. Lateral trochlear inclination, sulcus angle, and trochlear depth were measured. Groups were compared using paired t tests (alpha = 0.05). Correlations of anteroposterior TT–TG distance with lateral trochlear inclination, sulcus angle, and trochlear depth were assessed using linear and multivariate regression. ResultsMean TT–TG distances were 19.9 ± 4.4 mm (symptomatic) and 16.8 ± 5.5 mm (control) (mean ± std deviation) (P = 0.002). Mean anteroposterior TT–TG distances were 8.3 ± 7.8 mm (symptomatic) and −0.5 ± 4.6 mm (control) (P < 0.0001). The symptomatic group had greater measurements of trochlear dysplasia, with lower lateral trochlear inclination, greater sulcus angle, and lower trochlear depth (all P < 0.0001). Anteroposterior TT–TG distance and trochlear depth were strongly negatively correlated (r = 0.62, R2 = 0.39, P < 0.0001). ConclusionsIn asymptomatic patients, the anteroposterior TT–TG distance was −0.5 mm, indicating that the TG and TT were nearly in the same coronal plane. In patients with symptomatic patellar instability, the TG was almost nine millimeters anterior, and this distance correlated with measurements of trochlear dysplasia. Level of evidenceIII, case control study.

Trochleoplasty is a Viable Option for Patellar Instability in Patients with Severe Trochlear Dysplasia: a Minimum 1-year Follow-Up Prospective Study

Objectives: Patellar instability caused by trochlear dysplasia may be addressed by sulcus-deepening trochleoplasty. A paucity of data exists from the United States regarding this procedure and no long term follow up. The purpose of this study was to evaluate the outcome data of patients undergoing sulcus-deepening trochleoplasty for high-grade trochlear dysplasia at our institution. Methods: Sixty-four patients (71 knees) with severe trochlear dysplasia were prospectively enrolled and underwent sulcus-deepening trochleoplasty using the Dejour method from 2011-2018. Thirty-six of 71 knees (50.6%) had prior surgery and failed prior surgical management for patellar instability. Concomitant procedures during trochleoplasty were performed at varying rates. Radiographic analysis, physical examination, and clinical follow-up were obtained for all patients. At enrollment, patients completed preoperative visual analog scores (VAS), international knee documentation committee (IKDC) and Kujala scores, which were repeated at their 6 month, 1 year, 2 year, 3 year, and 4 year follow-up visits. Preoperatively, the patellotrochlear index (PTI), trochlear spur height, and trochlear depth were all measured. The patient’s sulcus angle was measured preoperatively and postoperatively on sunrise (merchant) view xray. Of the entire cohort, 43 patients (49 knees) had at least one year complete follow-up including xrays, physical exam, and patient-reported outcome measures and were included in the study. Results: The majority of patients were female (81.6%) with a mean age of 19.6 (+/- 6.8y). Follow-up ranged from 12 months to 78.4 months (mean 27.7 +/- 15.4). At the time of enrollment, mean BMI was 27.1 kg/m2 (+/-6.3) with one current smoker and one diabetic patient. Mean duration of symptoms prior to surgery was 75.2 months (+/- 72.5; r: 4-370mos). All knees were either Dejour B (81.3%) or D (18.8%) with a mean Caton-Deschamps index (CDI) of 1.20 (+/-0.2). Mean spur height preoperatively was 7.41 mm (+/1.84 mm) with a mean trochlear depth -0.18 (+/-2.71). Mean patellotrochlear index (PTI) was 0.41 (+/0.41). There were zero episodes of recurrent instability. All patients reported clinically significant improvements compared with baseline preoperative outcome scores. The mean preoperative IKDC score was 49.99, which improved to 79.86 (p&amp;lt0.001), and the mean preoperative Kujala score was 55.88, which improved to 85.80 (p&amp;lt0.001). Patients reported high satisfaction rates (9.5 +/-1.6 out of 10). All but 1 patient (96.9%) returned to work while 88.2% of patients were able to return to sport. Ten knees (20.4%) developed arthrofibrosis and required manipulation under anesthesia while eight of which underwent simultaneous arthroscopic lysis of adhesions. At the latest follow-up, mean knee range of motion was 132.4 +/- 13.2 degrees. Preoperative VAS was 3.31 (right) and 4.16 (left) while postoperative was 1.31 (right) and 1.76 (left) (p=0.007 R, 0.002 L). Radiographic analysis of the sulcus angle demonstrated a significant decrease from 148.86 degrees (+/-11.42) preoperatively to 135.11 degrees (+/-8.85) postoperatively (p&lt;0.001). Conclusion: In the setting of severe trochlear dysplasia, sulcus-deepening trochleoplasty can provide a reliable and successful surgical solution to recurrent patellar instability. At a minimum of one year follow-up, the majority of patients were satisfied with their outcome corroborated by their subjective, validated outcome measures.

Healthy knees have a highly variable patellofemoral alignment: a systematic review.

There is still lack of knowledge regarding the variability of patellofemoral alignment in healthy, non-osteoarthritic knees, without patellofemoral instability. Therefore, a systematic review of the existing literature was performed to evaluate the variability of patellofemoral alignment. Patellofemoral alignment of the knee was defined by the following parameters: sulcus angle (SA), femoral trochlear depth (FTD), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), lateral femoral trochlear inclination (LFTI) and tibial tubercle-trochlear groove distance (TT-TG). The electronic databases MEDLINE and EMBASE were searched from database inception to search date (January 11, 2019) and screened for relevant studies. The PRISMA guidelines were followed. Articles reporting PF alignment measurements of healthy knees in patients between 15years and 47years were included. A total of 15 studies met the inclusion criteria. The studies reported mean values and standard deviations for the SA between 118.7° ± 7 and 168°; for the FTD between 3.4mm ± 1.1 and 7.1mm ± 1.8; for the PTA between 0.7° ± 4.99 and 17.05° ± 4.3; for the LPFA between 6.26° ± 4.1 and 11.1° ± 4.0; for the LFTI between 16.3° ± 2.8 and 22.1° ± 1.9; and for the TT-TG between 9.8mm ± 4.6 and 17.3mm ± 5.3. Patellofemoral alignment in the healthy knee is extremely variable. A more precise knowledge of the complex relationship between the patella and the trochlea may help to better diagnose PF disorders and eventually help in selecting the correct therapy. Furthermore, standardised imaging protocols and measurement techniques for patellofemoral parameters are needed. III.

Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Regardless of Tibial Tubercle–Trochlear Groove Distance and Patellar Height: Outcomes at 1 and 2 Years

Background: It is unclear which patients with recurrent patellar instability require a bony procedure in addition to medial patellofemoral ligament (MPFL) reconstruction. Purpose: To report 1- and 2-year outcomes of patients after isolated MPFL reconstruction performed for patellar instability regardless of patellar height, tibial tubercle–trochlear groove (TT-TG) distance, or trochlear dysplasia. Study Design: Case series; Level of evidence, 4. Methods: All patients with recurrent patellar instability and without significant unloadable chondral defects (Outerbridge grade IV), cartilage defects (especially inferior/lateral patella), previous failed surgery, or pain >50% as their chief complaint were prospectively enrolled beginning March 2014. All patients underwent primary, unilateral, isolated MPFL reconstruction regardless of concomitant bony pathology for treatment of recurrent patellar instability. Information on recurrent subjective instability, dislocations, ability to return to sport (RTS), and outcome scores was recorded at 1 and 2 years. TT-TG distance, patellar height (with the Caton-Deschamps index), and trochlear depth were measured. Results: Ninety patients (77% female; mean ± SD age, 19.4 ± 5.6 years) underwent MPFL reconstruction between March 2014 and August 2017: 72 (80%) reached 1-year follow-up, and 47 (52.2%) reached 2-year follow-up (mean follow-up, 2.2 years). Mean TT-TG distance was 14.7 ± 5.4 mm (range, –2.2 to 26.8 mm); mean patellar height, 1.2 ± 0.11 mm (range, 0.89-1.45 mm); and mean trochlear depth, 1.8 ± 1.4 mm (range, 0.05-6.85 mm). Ninety-six percent of patients at 1 year and 100% at 2 years had no self-reported patellofemoral instability; 1 patient experienced a redislocation at 3.5 years. RTS rates at 1 and 2 years were 90% and 88%, respectively. Mean time to RTS was 8.8 months. All patients had clinically and statistically significant improvement in mean Knee injury and Osteoarthritis Outcome Score–Quality of Life (32.7 to 72.0, P < .001), mean International Knee Documentation Committee subjective form (51.4 to 82.6, P < .001), and mean Kujala score (62.2 to 89.5, P < .001). No difference existed between 1- and 2-year outcome scores (all P > .05). Conclusion: At early follow-up of 1 and 2 years, isolated MPFL reconstruction is an effective treatment for patellar instability and provides significant improvements in outcome scores with a low redislocation/instability rate regardless of bony pathologies, including TT-TG distance, Caton-Deschamps index, and trochlear dysplasia. Future data from this cohort will be used to assess long-term outcomes.

Femoral trochlea does not remodel after patellar stabilization in children older than 10 years of age

Trochlear dysplasia is a major risk factor for patellar instability. It has been sparsely reported that the trochlea can remodel when patellar stabilization is performed in skeletally immature patients before the age of 10 years. It is not known whether trochlea can remodel significantly after the age of 10 years. The purpose of the study was to evaluate trochlear remodeling in skeletally immature patients after patellar stabilization surgery, with a focus on children older than 10 years of age. In a retrospective study, knee MRI of 21 patients who had undergone patellar stabilization surgery, were evaluated. Twenty of these 21 patients were older than 10 years of age at time of surgery. The measurements of cartilaginous and bony sulcus angles, trochlear depth, and cartilaginous trochlear bump were compared between preoperative and postoperative MRI, using paired t-tests. In 20 patients older than 10 years of age, the mean cartilaginous sulcus angle change between preoperative and postoperative axial MRI was not significant (2.2°±7.9°, P=0.6). The mean change in the bony sulcus angle value was not significant (3.6°±6.8°, P=0.07). Similarly, there was no significant change in trochlear depth (P=0.8), or size of the trochlear bump (P=0.1). For one patient under 10 years of age at the time of surgery, there was a 21° and a 15° improvement in cartilaginous and bony sulcus angle, respectively. There were no significant changes in the trochlear parameters and trochlear remodeling in patients older than 10 years of age. Patellar stabilization at a younger age (<10 years), may allow for trochlear remodeling. Level of Evidence: Level IV, case series.

ARE THERE SIDE-TO-SIDE DIFFERENCES IN KNEE MORPHOLOGY IN PATIENTS WITH BILATERAL PATELLAR INSTABILITY

Introduction It is not known if there are side-to-side differences in knee morphology in patients with bilateral patellar instability (BPI). Such knowledge would help to answer the question whether similar treatment and prognosis could be expected for both knees in patients with BPI. The purpose of our study was to evaluate and compare anatomic / morphologic risk factors between knees in patients with BPI. Materials and Methods Of 294 patients who underwent surgical stabilization for patellar instability (2008-2017), 32 patients were identified who underwent staged or simultaneous bilateral surgery. This formed the study cohort. Demographic data, mechanism of initial injury and first knee side to be symptomatic were recorded. Radiographs and MRI of these 64 knees were evaluated for trochlear dysplasia (trochlear depth), patellar height (Caton-Deschamps index, Insall-Salvati ratio), patellar tilt, TT-TG distance, sulcus angle (cartilaginous and bony) and trochlear bump (cartilaginous and bony). The number and percentage of knees with pathologic values for measured risk factors were analyzed. For each risk factor, 15% side-to-side differences were considered significant. Statistical correlation was calculated between the time of presentation (first symptomatic knee) and magnitude of risk factors. All measurements were repeated after a 3-week interval and ICC was calculated to determine intraobserver reliability. Results The mean age of 32 patients was 14.6 years. 17/32 patients were females. 29 patients had staged surgery with mean interval of 21 months between surgeries; 3 patients had simultaneous surgery on each knee. Patients with BPI had multiple risk factors. 22/32 patients (69%) had the same Dejour type of trochlear dysplasia. For each measured risk factor, the number and percentage of patients with 15% or more side-to-side differences is shown (Table 1). There were significant side-to-side differences in patellar height ratios, TT-TG distance, and trochlear bump. The timing of presentation did not correlate with increased risk factors, i.e, the knee that presented earlier did not have increased risk factors compared to contralateral knee. ICC showed excellent intraobserver reliability. Conclusion There were significant side-to-side differences between knees in patients with BPI. Treatment and prognosis should be based on anatomic risk factors for each knee in patients with BPI. [Table: see text]

Trochlear Dysplasia and Its Relationship to the Anterior Distal Femoral Physis.

Trochlear dysplasia is a known risk factor for patellar instability in adolescent patients. A spatial relationship between dysplastic trochlea and anterior distal femoral physis has not been established. The purpose of this study was to investigate this relationship. Our hypothesis was that the position of the dysplastic trochlea and trochlear bump would coincide with the anterior distal femoral physis and that the distance between them would increase with age. In a retrospective study, magnetic resonance images of adolescents with trochlear dysplasia were evaluated. Measurements performed included trochlear depth, trochlear bump size, proximal trochlea-physis distance, and trochlear bump-physis distance. Linear regression analyses were performed to correlate the variables with increasing age. In total, 175 knees (160 patients) with trochlear dysplasia were included. The mean trochlea-physis distance was 4.50 mm (SD=1.93) and it increased with age (slope=0.26; P<0.01). The lateral aspect of trochlea was proximal to the physis in 24 (13.7%) knees and was at the level of the physis in 31 (17.7%) knees. The size of trochlear bump increased with age (slope=0.15; P=0.01). The bump-physis distance increased with age (slope=0.41; P<0.01). The dysplastic trochlea is closely related to the anterior distal femoral physis. The distance between the dysplastic trochlea and femoral physis increases with age. The close relationship between proximal aspect of trochlea and anterior distal femoral physis should be considered when trochlear surgery is planned in skeletally immature patients. Level II.

Quantitative magnetic resonance imaging in patellar tendon-lateral femoral condyle friction syndrome: relationship with subtle patellofemoral instability.

To investigate the correlation of patellar tendon-lateral femoral condyle friction syndrome (PTLFCFS) with subtle patellofemoral instability to explore its pathogenesis. One hundred knees of 80 patients with PTLFCFS were analyzed retrospectively by retrieving magnetic resonance imaging (MRI) data over a 3-year period from our database. Seven quantitative parameters for evaluating patellofemoral stability were measured on MR images, including the Insall-Salvati ratio, tibial tuberosity-trochlear groove (TT-TG) distance, trochlear groove depth, medial trochlear/lateral trochlear length (MT/LT) ratio, medial trochlear/lateral trochlear height (MH/LH) ratio, lateral patellofemoral angle (LPA), and lateral trochlear inclination (LTI) angle. These patellofemoral parameters of the PTLFCFS group and the normal control group were compared (n = 88), and receiving-operator characteristic (ROC) curve analysis was conducted to determine the specificity and sensitivity of these parameters. The trochlear depth, MT/LT, LPA, and LTI angle were significantly lower (p < 0.001) and the Insall-Salvati ratio was significantly higher (p < 0.001) in the PTLFCFS group. However, the TT-TG distance and MH/LH ratio showed no significant difference (p = 0.231 and 0.073 respectively). The area under the ROC curve of the Insall-Salvati ratio, trochlear depth, MT/LT, LPA, and LTI angle were 0.925, 0.784, 0.8, 0.731, and 0.675 respectively. The efficiency of the Insall-Salvati ratio was the highest among those five parameters. This study verified the presence of subtle patellofemoral instability by measuring various patellofemoral parameters in patients with PTLFCFS. It confirmed that PTLFCFS is associated with subtle patellofemoral instability and could largely explain the pathogenesis of PTLFCFS.

Magnetic resonance imaging of the quadriceps fat pad oedema pattern in relation to patellofemoral joint pathologies.

PurposeQuadriceps fat pad is located posterior to the quadriceps tendon. Increased signal intensity of this fat pad is seen on routine knee magnetic resonance imaging (MRI) examinations, but the exact mechanism and related pathologies are not clear. In this study we aimed to evaluate the relationship between MRI signal intensity and morphological features of quadriceps fat pad, as well as various pathologies of the patellofemoral joint.Material and methodsSixty-one knees with quadriceps fat pad oedema out of 457 knee MRI examinations were included. Quadriceps fat pad signal intensity, dimensions, posterior indentation, and various parameters related to patellofemoral joint such as trochlear facet asymmetry, trochlear depth and sulcus angle, and the Insall-Salvati ratio were evaluated.ResultsThere was no statistically significant correlation between quadriceps fat pad oedema intensity and its dimensions, but it was significant when compared to posterior indentation. There was no correlation between fat pad oedema and each of the pathologies. However, there was a significant correlation between the presence of fat pad oedema and the presence of at least one of the pathologies related to patellofemoral joint.ConclusionsQuadriceps fat pad oedema detected in MRI examinations should warn the radiologist against the presence of various pathologies related to the patellofemoral joint.

Computed Tomographic Trochlear Depth Measurement in Normal Dogs.

The main purpose of this study was to describe the relationship between patellar maximal craniocaudal thickness and femoral trochlear groove depth in normal dogs and to valuate the intra-observer or inter-observer variability of maximal trochlear depth and maximal patellar craniocaudal thickness using computed tomography. Trochlear groove depth and patellar maximal craniocaudal thickness of 40 limbs (20 dogs) were measured by three independent veterinarians using three-dimensional multiplanar reconstruction computed tomography images. The patellar maximal craniocaudal thickness/trochlear depth ratio was determined. The mean ratio of these stifles was 0.46 (range 0.24-0.70), meaning that the mean maximal depth of the trochlea was 46% of the mean maximal-patellar thickness. A wide range of maximal-patellar-craniocaudal-thickness/maximal trochlear-depth ratio was found suggesting that breed studies should be performed to determine a breed-specific patellar-thickness/trochlear-depth ratio. To make decisions on when and where to perform a sulcoplasty during patellar luxation surgery, patella/trochlea thickness relationship should be measured for each breed with patellar tracking from stifle hyperflexion to stifle hyperextension.

The association of patellar maltracking with infrapatellar fat pad edema and chondromalacia patella: A quantitative morphological magnetic resonance imaging analysis.

This study aims to investigate the relationship of patellofemoral joint morphology with infrapatellar fat pad edema and chondromalacia patella (CP) using patellar maltracking parameters on magnetic resonance imaging (MRI). Between January 2010 and January 2013, 50 patients with edema in the superolateral portion of the infrapatellar fat pad (the study group) and control group (n=50) with a normal infrapatellar fat pad were identified on MRI to compare with regard to five patellar maltracking parameters retrospectively. These parameters were trochlear depth, the trochlear sulcus angle (TSA), patellar translation, the lateral patellofemoral angle (PFA), and the Insall-Salvati ratio. The relationship between patellar maltracking and the CP was also evaluated using the same parameters. In the study group, the Insall-Salvati index and TSA were significantly higher (p=0.001), and the trochlear depth and PFA were low (p=0.001, p=0.01), while patellar translation showed no difference (p=0.957). In the CP group, the Insall-Salvati index and TSA were significantly high (p=0.001), the trochlear depth was low (p=0.001). No statistically significant difference was found in PFA and patellar translation (p=0.292, p=0.446). Our study results suggest that edema in the superolateral portion of infrapatellar fat pad and CP are associated with patellar maltracking.

A combined procedure with Bereiter-type trochleoplasty leads to a stable patellofemoral joint at 5-year follow-up.

Trochlear dysplasia is a major risk factor predisposing to patellar instability and has been reported to occur in up to 85% of patients with recurrent patellar dislocation. Different operative techniques have been described to correct trochlear dysplasia, including the Bereiter technique, in which subchondral bone is removed and the cartilage can be compressed into a U-shaped groove. The hypothesis was that after a Bereiter-type trochleoplasty combined with medialisation of the tibial tubercle and MPFL reconstruction, patellar pain and instability decreased and anatomic reconstruction can be seen radiographically after 5-year follow-up. Between 2004 and 2011, a combined procedure including Bereiter-type trochleoplasty was performed on 21 consecutively included patients (22 knees) with objective patellar instability and severe trochlear dysplasia. Instability and pain were assessed preoperatively and 3, 6, 12, 24 and 60months postoperatively with the visual analogue scale (VAS) for pain and instability, Kujala, International Knee Documentation Committee Subjective Knee Evaluation (IKDC SKE) and Short Form Health Survey (SF-36). Pre- and postoperatively, a true lateral radiograph was made to investigate the presence of the crossing sign and to measure the trochlear bump and trochlear depth, as well as a sunrise patella view to measure the sulcus angle. VAS pain and instability, Kujala and IKDC SKE improved significantly 5 years after trochleoplasty (p < 0.05). SF-36 showed no significant improvement. None of the patients reported patellar dislocations postoperatively. Sport activities remained limited. Postoperative radiographs showed no crossing sign. There was a significant increase in trochlear depth (p < 0.0001) and also a significant decrease in trochlear bump and sulcus angle (both p < 0.0001). A combined procedure consisting of Bereiter-type trochleoplasty, medialisation of the tibial tubercle and MPFL reconstruction in patients with objective patellar instability and severe trochlear dysplasia resulted in a clear decrease of pain and instability. Radiological assessment showed anatomical reconstruction. Nevertheless, residual symptoms remain and the possibility of future cartilage damage is uncertain. IV.

Operative Repair of Medial Patellofemoral Ligament Injury Versus Knee Brace in Children With an Acute First-Time Traumatic Patellar Dislocation: A Randomized Controlled Trial

Background: A lateral patellar dislocation (LPD) is the most common traumatic knee injury with hemarthrosis in children. The redislocation rate is high. Varying operative and nonoperative treatments have been advocated with no consensus on the best treatment. Purpose: (1) To evaluate if arthroscopic-assisted repair of the medial patellofemoral ligament (MPFL) in patients with an acute first-time traumatic LPD would reduce the recurrence rate and offer better objective/subjective knee function compared with a knee brace without repair. (2) To study the presence of anatomic patellar instability risk factors (APIFs) and their association with a redislocation. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: This was a prospective series of 74 skeletally immature patients aged 9 to 14 years (38 girls and 36 boys; mean age, 13.1 years) with a first-time traumatic LPD, with clinical examinations, radiographs, magnetic resonance imaging, and diagnostic arthroscopic surgery performed within 2 weeks of the index injury. The child was randomized to either (1) a knee brace (KB group) for 4 weeks and physical therapy or (2) arthroscopic-assisted repair (R group) of the MPFL with anchors, 4 weeks with a soft cast splint, and physical therapy. The follow-up time was 2 years. Results: The redislocation rate was significantly lower in the R group than in the KB group at final follow-up: 8 patients (22%) versus 16 patients (43%), respectively (P = .047). The Knee injury and Osteoarthritis Outcome Score for children sport/play and quality of life subscales had lower scores in the R group compared with the KB group; the significant differences were among those with redislocations. The mean Kujala score was excellent in the KB group (95.9) and good in the R group (90.9). An impaired Limb Symmetry Index (median, 83%) for concentric quadriceps torque at 90 deg/s was found only in the R group. Eighty-one percent of the study patients had ≥2 APIFs. Trochlear dysplasia (trochlear depth <3 mm) had the highest odds ratio for redislocations (2.35 [95% CI, 0.69-8.03]), with no significant association between APIFs and a redislocation. Conclusion: Operative repair of an MPFL injury in the acute phase in skeletally immature children with a primary traumatic LPD significantly reduced the redislocation rate but did not improve subjective or objective knee function compared with a knee brace without repair. The majority of the patients in both groups were satisfied with their knee function. There was a high representation of APIFs, which needs to be considered when evaluating the risk of redislocations. Registration: ISRCTN 39959729 (Current Controlled Trials).

Does different duration of non-operative immobilization have an effect on the redislocation rate of primary patellar dislocation? A retrospective multicenter cohort study

BackgroundImmobilization devices such as plaster splints, casts and braces have been used for first time patellar dislocation (FTPD) in order to prevent redislocation. This study evaluates different non-operative immobilization regimes upon rates of redislocation. MethodsA retrospective cohort study with a study population of 1366 in which 601 subjects under 30years with FTPD were included from three hospitals. Exclusion criteria were osteochondral fracture, ligament injury and subluxation. Subjects were divided into five groups; unknown/none, two weeks of brace, two weeks of brace followed by bandage, four weeks of brace and six weeks of brace with increasing of range of motion. Radiographs were evaluated for trochlear dysplasia (TD), patella alta, trochlear depth and growth zone. Crude analysis and logistic regression adjusted for radiographic assessments, age, gender and rehabilitation was done in STATA® with significance p≤0.05. ResultsForty-five point eight percent were between 15 and 19years and 51.4% were male. One hundred sixty-three experienced redislocation (27.1%). Logistic regression was performed at 404 subjects and showed that rehabilitation, gender, TD, patella alta, and growth zone had no significant odds ratio (OR) on redislocation. The duration of brace demonstrated no significant OR in reducing redislocation. Subjects between 20 and 29years showed lower OR in redislocation (95% CI) of 0.27 (0.11; 0.64, p=0.003). ConclusionThis study demonstrated no difference in duration of brace treatment in reducing patella redislocation after FTPD. Rehabilitation and predisposal factors such as TD, trochlear depth, patella alta and open growth zone did not influence the redislocation rate. Increasing age reduced risk of redislocation.

Angular dimensions and squatting facets in human dry tali of South Indian origin

The angular dimensions of the talus are indicative of its biomechanical role in load transmission. Squatting facets on the neck of the talus are indicative of habitual squatting. The primary objective of this study was to estimate the strength of association between the talar angles and the presence of squatting facets. The secondary objectives were to estimate the side differences in the angular dimensions and to assess the reliability of the method. One hundred and sixty dry tali of unknown sex were studied. The neck angle, vertical angle, torsion angle, trochlear surface angle and depth angle were measured using a photographic method. The presence of squatting facets was noted. The mean and standard deviation of those angles were 108.3 ± 5.23, 89.87 ± 3.97, 37.57 ± 5.62, 9.7 ± 3.3 and 156 ± 5.1 degrees respectively. The neck, vertical and depth angles were significantly higher on the left side. There were significant positive correlations between the neck and vertical angles, the neck and depth angles and the torsion and depth angles. Squatting facets were noted in 90 of the 160 (56%) of the tali. The torsion angle was significantly higher in tali with squatting facets. Intraobserver and inter-observer reliability of the methods were found to be good to excellent. The findings of this study indicate the factors that can possibly influence the magnitude of the talar angles. This data can be useful for designing talar prostheses and analyzing the biomechanical interface of the hind foot bones.

How Do Axial Scan Orientation Deviations Affect the Measurements of Knee Anatomical Parameters Associated with Patellofemoral Instability? A Simulated Computed Tomography Study.

The purpose of this study was to detect the correlation between axial scan orientation discrepancy and the knee anatomical parameters associated with patellofemoral instability during computed tomography (CT) scanning. CT scan data of 16 knees from 16 healthy subjects were retrieved. The reslicing processes were performed to simulate different axial scan orientations generated due to leg adduction/abduction during CT scanning. Eight parameters (tibial tubercle to trochlear groove [TT-TG], tibial tubercle to posterior cruciate ligament [TT-PCL], patellar tilt, lateral trochlear inclination, sulcus angle, trochlear depth, trochlear facet asymmetry, and trochlear condyle asymmetry) of five angles (neutral zero, 4/8 degrees of adduction and 4/8 degrees abduction) were quantified. All eight parameters showed varying degrees of deviations to the different axial scan orientations. TT-TG, patellar tilt, lateral trochlear inclination, and trochlear condyle asymmetry were relatively sensitive to axial scan orientation changes, whereas TT-PCL, sulcus angle, trochlear depth, and trochlear facet asymmetry were relatively insensitive. Although the sensitivities are various, surgeons should be aware of this situation and make necessary corrections.

The Anterior-posterior Distance Between the Tibial Tuberosity and Trochlear Groove

Objectives:Tibial tuberosity osteotomy is often performed to correct excessive lateralization of the tuberosity in patients with patellar instability. An anteriorizing component has been recommended in the setting of chondral pathology, yet the ideal anterior-posterior relationship of the tibial tuberosity to the trochlear groove is unknown.Methods:Patients with symptomatic patellar instability underwent static CT imaging, and were compared to age- and gender-matched controls. All knees were imaged in full extension. Tibial-tuberosity-trochlear-groove (TTTG) distance was measured to quantify lateralization of the tuberosity, as well as the anterior-posterior distance between these two points (APTTTG distance). Lateral trochlear inclination (LTI), sulcus angle (SA) and trochlear depth (TD) were measured as indicators of trochlear dysplasia. Measurements were compared between the symptomatic and control groups using paired t-tests. Correlations between APTTTG with LTI, SA and TD were assessed using linear regression analyses.Results:22 knees in 18 patients with symptomatic patellar instability were included in the study group, with 22 control knees. TTTG and APTTTG distances were 19.9 mm and 8.3 mm in the symptomatic group, versus 16.8 mm and -0.5 mm in the control group, with a difference of 3.1 mm (p=0.002) and 8.8 mm (p<0.0001) respectively. The symptomatic group displayed greater trochlear dysplasia with lower LTI (13.0° vs 21.9°, p<0.0001), higher SA (152.7° vs 137.7°, p<0.0001) and lower TD (1.3mm vs 6.0mm, p<0.0001). There was strong correlation between APTTTG and TD (r=0.62, R2=0.39, p<0.0001).Conclusion:Our findings demonstrate that the trochlear groove is almost 9mm more anterior to the tibial tuberosity in patients with symptomatic instability, and this distance correlates with measurements of trochlear dysplasia. While further studies are needed to determine the relationship between APTTTG distance and patellar instability, these findings suggest that the anterior-posterior relationship between the trochlea and tuberosity may be a factor to consider when planning for tibial tuberosity osteotomy in patients with trochlear dysplasia.