Association between trochlear morphology and chondromalacia patella: an MRI study

Sex differences in patellar facet shape among healthy and osteoarthritic cohorts

OBJECTIVE

Patellofemoral osteoarthritis (OA) may be more common in females than males. Reasons for this are not fully understood, but sex differences in patellar morphology may help explain this phenomenon. We quantified differences in patellar morphology between males and females in healthy and patellofemoral OA populations.

DESIGN

A total of 97 (50F, 47M) healthy and 67 (40F, 27M) OA knees were scanned via computed tomography. OA individuals were on a waitlist for total knee replacement. Patella 3D models were segmented and 2D measurements were recorded: patellar width and height, lateral and medial facet width, and surface area. Medial and lateral facet surface topography was mapped using 81 points to describe 3D articular surface shape. Sex and group differences were assessed using Procrustes analysis of variance (ANOVA). Data were ordinated using Principal Component Analysis.

RESULTS

Differences in patellar 2D measurements between healthy and OA individuals were smaller than were differences between males and females from healthy and OA groups. Sex and healthy/OA differences were most pronounced for medial facet shape, which featured a posteriorly-curving facet and taller, narrower facet shape in males compared to females. Lateral facet shape variance was higher in OA cohorts compared to healthy groups.

CONCLUSIONS

Medial and lateral facet shapes showed different patterning of variation by sex and healthy/OA status. Lateral facet shape may be of interest in future models of OA risk in the patellofemoral joint, here showing increased magnitudes of variance associated with increased severity of disease (patellofemoral Kellgren and Lawrence score).

Supratrochlear Rim is Correlated with Isolated Patellar Chondromalacia on Magnetic Resonance Imaging of the Knee

Purpose

To investigate the relationship between the supratrochlear rim and isolated patellar chondromalacia (PC) using magnetic resonance imaging (MRI) scans of the knee.

Methods

Patients without patellofemoral pain (control group) and patients with patellofemoral pain and diagnosed with stage III or IV PC based on MRI (defect group) were retrospectively identified. Patients with a history of patellar subluxation were excluded. We used patient MRI scans to perform 20 anatomical measurements of the patellofemoral joint. We also performed 2 measurements of the anterior femoral curvature. A total of 30 patients (29 ± 8.7 years) were in the control group, and 20 patients were in the defect group (29.4 ± 9.7 years).

Results

The maximum curvature (P < .001) and mean curvature (P < .001) of the anterior femoral condyle were found statistically significantly different between the groups. Patellotrochlear index (P = .03) and Insall-Salvati index (P < .001) were also found statistically significantly different between the 2 groups. Patella type III and trochlear dysplasia grade B were found more common in the defect group.

Conclusions

In this Level III prognostic, case-control study, we have shown through MRI knee measurements that the isolated patellar chondromalacia in patients without a history of patellar subluxation and dislocation is correlated with the increased anterior femoral curvature in combination with patella alta.

Magnetic Resonance Image Findings and Potential Anatomic Risk Factors for Chodromalacia in Children and Adolescents Suffering from Non-Overload Atraumatic Knee Pain in the Ambulant Setting

PURPOSE

To evaluate magnetic resonance image (MRI) findings in children and adolescents suffering from knee pain without traumatic or physical overload history and to identify potential anatomic risk factors.

MATERIAL AND METHODS

A total of 507 MRIs of 6- to 20-year-old patients (251 males; 256 females) were evaluated with regard to detectable pathologies of the knee. The results were compared to a control group without pain (n = 73; 34 males; 39 females). A binary logistic regression model and t-tests for paired and unpaired samples were used to identify possible risk factors and significant anatomic differences of the study population.

RESULTS

In 348 patients (68.6%), at least one pathology was detected. The most commonly detected finding was chondromalacia of the patellofemoral (PF) joint (n = 205; 40.4%). Chondral lesions of the PF joint occurred significantly more often in knee pain patients than in the control group (40% vs. 11.0%; p = 0.001), especially in cases of a patella tilt angle > 5° (p ≤ 0.001), a bony sulcus angle > 150° (p = 0.002), a cartilaginous sulcus angle > 150° (p = 0.012), a lateral trochlear inclination < 11° (p ≤ 0.001), a lateralised patella (p = 0.023) and a Wiberg type II or III patella shape (p = 0.019). Moreover, a larger patella tilt angle (p = 0.021), a greater bony sulcus angle (p = 0.042), a larger cartilaginous sulcus angle (p = 0.038) and a lower value of the lateral trochlear inclination (p = 0.014) were detected in knee pain patients compared to the reference group.

CONCLUSION

Chondromalacia of the PF joint is frequently observed in children and adolescents suffering from non-overload atraumatic knee pain, whereby a patella tilt angle > 5°, a bony sulcus angle > 150°, a cartilaginous sulcus angle > 150°, a lateral trochlear inclination < 11°, a lateralised patella and a Wiberg type II or III patella shape seem to represent anatomic risk factors.

Relationship between patellofemoral joint morphology and chondromalacia patella

BACKGROUND

For the normal functioning of the patellofemoral joint (PF), the relationship between the patella and the trochlear groove must be compatible.

PURPOSE

To investigate the relationship between patellofemoral joint morphology (PFM) and patellar chondromalacia.

MATERIAL AND METHODS

Overall, 136 knees of patients aged 20-55 years examined between March 2020 and March 2021 were included in this study. In all patients, trochlear sulcus angle, trochlear sulcus depth, trochlear facet asymmetry, patella alta (Insall-Salvati [IS] index), and patellar facet asymmetry were measured. Of these cases, 66 knees with an abnormality detected in any of the measurements for PFM were included in the case group. Moreover, 70 knees with demonstrating normal PFM measurements were included in the control group.

RESULTS

The incidence and grade of chondromalacia was higher in the case group than in the control group (P < 0.001). Between the patients with and without chondromalacia trochlear sulcus angle (mean = 138.25° ± 10.02° vs. 132.58° ± 7.24°; P = 0.001), IS index (mean = 1.25 ± 0.21 vs. 1.16 ± 0.15; P = 0.014), patellar facet asymmetry (mean = 0.77 ± 0.09 vs. 0.73 ± 0.12; P = 0.039), trochlear sulcus depth (mean = 5.39 ± 1.42 mm vs. 6.27 ± 1.04 mm; P < 0.001), and trochlear facet asymmetry (mean = 0.67 ± 0.11 vs. 0.71 ± 0.09; P = 0.023) measurements, there was a significant difference.

CONCLUSION

The presence of at least one of the measures indicating pathology in PFM is associated with the presence and severity of chondromalacia.

Evaluation of the relationship between trochlear and patellar morphology and patellar chondromalacia with magnetic resonance imaging

It was aimed to investigate the relationship between magnetic resonance imaging (MRI) measurements of trochlear and patellar morphology and grade 3-4 patellar chondromalacia. Grade 3-4 patellar chondromalacia group, and an age- and sex-matched control group with normal patellar joint cartilage were comprised. For trochlear morphology evaluation in MRI; sulcus angle, trochlear angle, lateral trochlear inclination angle and medial trochlear inclination angle were measured. For patellar morphology evaluation; patella trochlear ratio, insall-salvati ratio, modified Insall- Salvati ratio and Blackburne-Peel ratio were measured. Obtained measurements were statistically analyzed according to demographic characteristics. One hundred and twenty-five patients with chondromalacia and 125 controls participated. The sulcus angle and the trochlear angle were significantly higher in the patellar chondromalacia group (p<0.05). The lateral trochlear inclination angle was significantly less in the patellar chondromalacia group (p=0.011). There was no significant difference between the groups in terms of medial trochlear inclination angle (p=0.520). There was no significant difference between the groups in terms of patella-trochlear ratio (p=0.617). Insall-Salvati ratio was significantly higher in the patellar chondromalacia group (p=0.003). Modified Insall-Salvati ratio was significantly lower in the patellar chondromalacia group (p=0.001). The rate of Blackburne-Peel was significantly higher in the patellar chondromalacia group (p=0.004). Measurements of sulcus angle, trochlear angle, lateral trochlear inclination angle, Insall-Salvati ratio, modified Insall-Salvati ratio, Blackburne-Peel ratio have diagnostic value for grade 3-4 chondromalacia.

Assessment of patellar cartilage cross-sectional area in patients with lower grade chondromalacia patella

Chondromalacia patella (CMP) is abnormal softening of the cartilage of the underside the patella. It is a cause of anterior knee pain. Previous study has demonstrated that the patellar cartilage hypertrophy is correlated with early signs of CMP (Grade 1 or 2). However, no studies have investigated the clinical cutoff value of patella cartilage hypertrophy. Thus, we devised the patellar cartilage cross-sectional area (PCCSA) as a new predictive parameter for diagnosing the CMP. The purpose of this research was to compare MR measured PCCSA between CMP patients and gender matched healthy controls. The PCCSA samples were collected from 50 patients with CMP, and from 50 healthy controls who underwent knee MRI with no evidence of CMP. The T2-weighted turbo spin echo transverse MRI images were acquired. We measured the PCCSA on MRI using a PACS system. The PCCSA was measured on the axial angled sections through the whole images by drawing outlines. The average PCCSA was 104.28 ± 23.28 mm2 in the healthy controls and 134.09 ± 26.55 mm2 in the CMP group. CMP patients had significantly higher PCCSA (P < .001). Regarding the validity of PCCSA as predictors of CMP, Receiver Operating Characteristic curve analysis showed that the best cutoff point for the PCCSA was 116.24 mm2, with 72.0% sensitivity, 72.0% specificity, and the area under curve (AUC) of 0.79 (0.71-0.88). The PCCSA is a sensitive measurement parameter to predict low grade CMP. Thus, to evaluate CMP patients, the treating physician carefully inspect the PCCSA.

Atlas-Based Segmentation in Extraction of Knee Joint Bone Structures from CT and MR

The main goal of the approach proposed in this study, which is dedicated to the extraction of bone structures of the knee joint (femoral head, tibia, and patella), was to show a fully automated method of extracting these structures based on atlas segmentation. In order to realize the above-mentioned goal, an algorithm employed automated image-matching as the first step, followed by the normalization of clinical images and the determination of the 11-element dataset to which all scans in the series were allocated. This allowed for a delineation of the average feature vector for the teaching group in the next step, which automated and streamlined known fuzzy segmentation methods (fuzzy c-means (FCM), fuzzy connectedness (FC)). These averaged features were then transmitted to the FCM and FC methods, which were implemented for the testing group and correspondingly for each scan. In this approach, two features are important: the centroids (which become starting points for the fuzzy methods) and the surface area of the extracted bone structure (protects against over-segmentation). This proposed approach was implemented in MATLAB and tested in 61 clinical CT studies of the lower limb on the transverse plane and in 107 T1-weighted MRI studies of the knee joint on the sagittal plane. The atlas-based segmentation combined with the fuzzy methods achieved a Dice index of 85.52-89.48% for the bone structures of the knee joint.

Prevalence of chondromalacia patella according to patella type and patellofemoral geometry: a retrospective study

BACKGROUND

The relationships between the morphometric structure of the patellofemoral joint, patella type and chondromalacia patella are still a matter of debate.

OBJECTIVE

To identify the prevalence of chondromalacia patella by determining the patella type and making patellofemoral morphometric measurements.

DESIGN AND SETTING

Retrospective cohort study in an orthopedics and traumatology clinic in Turkey, conducted between June 2017 and November 2019.

METHODS

This study involved 562 knees of 522 patients with anterior knee pain (246 males and 316 females; mean age 46.59 years). The patients were grouped according to presence of chondromalacia patella (group I) or absence of chondromalacia patella (group II). The patella type, lateral trochlear inclination, medial trochlear inclination, trochlear angle, sulcus angle, patellar tilt and Insall-Salvati index were assessed. Group comparisons were made using chi-square tests or Student t tests. The r value was used to determine the magnitude of relationships between pairs of variables.

RESULTS

Among the 562 knees evaluated, 265 (50.71%) presented type I patella, 195 (36.7%) type II, 100 (12.3%) type III and 2 (0.3%) type IV. Group I consisted of 448 knees and group II consisted of 114 knees. Significant differences were found between the groups in terms of age, gender, patella type and lateral inclination angles (P &lt; 0.05).

CONCLUSION

Detecting the patella type and making lateral inclination measurements in patients with anterior knee pain are of great importance for diagnosing suspected chondromalacia patella, particularly in the early degenerative period.

The SP-ET index is a new index for assessing the vertical position of patella

Background

Some parameters in previous studies did not better reflect the vertical position of the patella relative to the femoral trochlear. This study aimed to assess the value of the most superior point of patella-entrance of femoral trochlea distance ratio (SP-ET index) as a newer index in defining the vertical position of patella relative to the trochlea, correlate it with the Insall–Salvati ratio, and investigate the effect of the new index on patellar cartilage lesions.

Methods

A total of 99 knees of 77 patients with patellar cartilage lesions were retrospectively analyzed using magnetic resonance imaging (MRI) data. The Insall–Salvati ratio and SP-ET index were measured on MR images. Ninety-nine knees just with meniscus rupture were enrolled as the control group. The two parameters of the patellar cartilage lesions were compared with those of the control group.

Results

The Insall–Salvati ratio and SP-ET index in the patellar cartilage lesions group were significantly higher than those in the control group (p < 0.001). The SP-ET index showed a moderate positive correlation with the Insall–Salvati ratio (r = 0.307, p < 0.001). Receiver operating characteristic (ROC) analysis showed that the diagnostic efficiency of the SP-ET index was better than that of the Insall–Salvati ratio in patients with patellar cartilage lesions.

Conclusion

The SP-ET index may be a useful complement parameter to define the vertical position of the patella relative to the femoral trochlear. Increased SP-ET index may be an important risk factor for patellar cartilage lesions.

Femur-tibia angle and patella-tibia angle: new indicators for diagnosing anterior cruciate ligament tears in magnetic resonance imaging

Background

Femur-tibia angle (FTA) and patella-tibia angle (PTA) are two MRI measurements that reflect the rotation of the knee joint. The purposes of this study were to assess whether FTA and PTA are associated with ACL tear and to explore their roles in ACL tear diagnosis.

Methods

FTA, PTA, ACL angle and anterior tibial subluxation were compared between the two matched groups: ACL tear group and control group (each n = 20). Diagnostic performance was evaluated in a consecutive 120-patient cohort who underwent MR imaging of the knee and subsequently had arthroscopy. Different measurements were assessed by area under the curve (AUC) of receiver operating characteristic (ROC) curve.

Results

FTA and PTA increased significantly in ACL tears group when compared to the control group (4.79 and 7.36 degrees, respectively, p < 0.05). In distinguishing complete ACL tear, ACL angle had the highest AUC of 0.906 while AUC of PTA and FTA were 0.849 and 0.809. The cutoff of FTA was 80 degrees with a sensitivity of 82% and specificity of 68%, while the cutoff of PTA was 91 degrees with a sensitivity of 82% and specificity of 74%. In distinguishing partial ACL tear, FTA and PTA had the highest AUCs of 0.847 and 0.813, respectively. The calculated cutoff of FTA was 84 degrees with a sensitivity of 90% and specificity of 81%, while the cutoff of PTA was 92 degrees with a sensitivity of 80% and specificity of 77%.

Conclusion

FTA and PTA increased when ACL tears and they might be valuable in diagnosing ACL tears, especially in distinguishing partial ACL tear from intact ACL.

Relationship between Anatomical Risk Factors, Articular Cartilage Lesions, and Patient Outcomes Following Medial Patellofemoral Ligament Reconstruction

OBJECTIVE

The purpose of this study was (1) to determine which risk factors for patellar instability were associated with the presence of patellofemoral cartilage lesions and (2) to determine how cartilage lesion presence, size, and grade affect postoperative disease-specific quality of life.

DESIGN

Preoperative, intraoperative, and postoperative demographic, anthropometric (body mass index, Beighton score, hip rotation), radiographic (crossover sign, trochlear bump), cartilage lesion morphology (presence, size, location, grade), and outcomes data (Banff Patella Instability Instrument 2.0 [BPII 2.0]) were prospectively collected from patients undergoing isolated medial patellofemoral ligament reconstruction. For all knees (n = 264), single and multivariable logistic regression was used to determine if any patellar instability risk factors affected the odds of having a cartilage lesion. In patients with unilateral symptoms (n = 121), single variable linear regression was used to determine if the presence, size, or ICRS (International Cartilage Regeneration & Joint Preservation Society) grade of cartilage lesions could predict the 12 or 24+ month postoperative BPII 2.0 score.

RESULTS

A total of 84.5% of knees had patellofemoral cartilage lesions (88.3% involved the distal-medial patella). Trochlear dysplasia (high grade: odds ratio = 15.7, P < 0.001; low grade: odds ratio = 2.9, P = 0.015) was associated with the presence of a cartilage lesion. The presence, size, and grade of cartilage lesions were not associated with 12 or 24+ month postoperative BPII 2.0 scores.

CONCLUSIONS

Trochlear dysplasia was a risk factor for the development of patellofemoral cartilage lesions in this patient population. Cartilage lesions most commonly involve the distal-medial patella. There was no significant relationship between patellofemoral cartilage lesion presence, size, or grade and postoperative BPII 2.0 scores in short-term follow-up.

Correlation between Chondromalacia Patella and Patellofemoral Factors in Middle-Age Population: A Clinical, Functional, and Radiological Analysis

Background Despite higher incidence of patellofemoral pain (PFP) and consequently morbidity, the understanding about PF factors leading to PF arthritis is way lacking.

Material and Methods A prospective study of first 80 patients who were diagnosed with chondromalacia patella (CMP) on magnetic resonance imaging (MRI) divided into early and late CMP groups were evaluated clinically, radiologically, and in terms of functional outcome.

Results : Quadriceps angle, Clark’s test, and Insall–Salvati ratio results were nonsignificant despite greater values were observed in late CMP group, whereas trochlear morphology results (sulcus angle: 153:138 degrees and sulcus depth 3.9:5.4 mm) and clinical scores were significant in late CMP group (Kujala’s score: 61:78, whereas PF pain score: 43:25). Type-C patellar morphology was found in greater number in late CMP cohort.

Conclusion Trochlear and patellar morphologies along with clinical scores play a key role in understanding of the CMP.

Investigation of the relationship between trochlear morphology and medial patellar cartilage defect using magnetic resonance imaging

The aim of this study was to evaluate trochlear morphology in patients with medial patellar cartilage defects via magnetic resonance imaging (MRI). Three hundred patients who were diagnosed with grade 2, 3 and 4 medial patellar cartilage defect using MRI according to the International Cartilage Repair Society Classification System and 100 control subjects were evaluated. Trochlear morphology was evaluated based on lateral trochlear inclination (LTI), medial trochlear inclination (MTI), sulcus angle( SA), femoral lateral and medial condyle symmetry, trochlear facet asymmetry, and trochlear width on the axial MR images. The mean SA was significantly higher in the medial patellar cartilage defect group compared to the control group (p<.05). The LTI and MTI of the cartilage defect group were significantly lower than those of the control group (p<.05). With the decreasing LTI and MTI, there was an increase in medial patellar cartilage loss. LTI (r=-0.46) and MTI (r=-0.53) were moderately correlated with SA. There was no significant differences in femoral lateral and medial condyle symmetry, trochlear facet asymmetry, and trochlear width between groups with and without medial patellar cartilge defect (p > .05). A flattened medial trochlea is a risk factor for cartilage structural damage of the medial patellofemoral joint, and it plays a role in the development of a defect in the medial patellar cartilage. The medial patellar cartilage defect is associated with the flattened lateral trochlea.

An association between femoral trochlear morphology and non-contact anterior cruciate ligament total rupture: a retrospective MRI study

INTRODUCTION

The present study aims to investigate the association of the femoral trochlear morphology with the risk of ACL injury and whether this can be considered an additional risk factor in this clinical table.

MATERIALS AND METHODS

This is a retrospective case-control study with 93 patients, 41 patients with ACL total rupture (ACL-TR), and 52 patients without ACL injury who underwent knee magnetic resonance imaging (MRI) between January 2013 and January 2016. The femoral trochlear morphology was evaluated at the proximal and distal levels from the axial knee MRI. The morphological features of the trochlea using sulcus angle, sulcus depth, condylar heights, trochlear sulcus height, percentage of condyles and trochlear sulcus height to transepicondylar width, and lateral and medial trochlear inclination were evaluated. The notch width index was measured on the coronal MR images for notch stenos.

RESULTS

ACL-TR group had a significantly higher sulcus angle (p = 0.00-0.001) and lower sulcus depth (p = 0.00-0.002) than the control group at both levels. Femoral trochlea had morphometric differences between genders. NWI was lower in the ACL-TR group than the control group (control 0.273; ACL-TR 0.247), and there was a statistically significant difference (p = 0.00).

CONCLUSION

This study was shown that the difference in morphology between the trochlear sulcus of patients with normal and ACL injuries should be taken into account in order to increase awareness of ACL injuries. We observed that mild trochlear dysplasia may cause intercondylar notch stenosis rather than changing the localization of the patella. Studies are needed regarding the effect of trochlear dysplasia on ACL.

Prevalence of patellar chondropathy on 3.0 T magnetic resonance imaging

Objective

To establish the prevalence of patellar chondropathy using 3T magnetic resonance imaging (MRI) and to correlate the findings with individual features such as gender, age, and body mass index.

Materials and Methods

Data consisted of collecting 3T MRIs of patients’ knees obtained between October 2016 and September 2017, comprising a period of 12 months. These MRIs were assessed by an experienced musculoskeletal radiologist who confirmed the presence of patellar chondropathy and, when present, rated the finding into the four grades ascribed by the International Cartilage Repair Society.

Results

A total number of 291 patients were assessed during the period with 389 MRI scans. Of those patients, 308 (79.2%) were diagnosed with patellar chondropathy, while 81 (20.8%) were not. Chondropathy was more prevalent in the female gender, in subjects above 40 years of age, and in obese patients. When the results were weighed in International Cartilage Repair Society classification, the milder grades (1 and 2) were seen in younger men (< 30 years of age), while the more severe grades (3 and 4) were mostly present in females, those above 40 years of age, and in obese patients.

Conclusion

There was a high prevalence of patellar chondropathy in patients who had undergone high-field knee MRIs (79.2%), being highest in the female gender and in subjects above 40 years of age. The most prevalent group was graded as 4 by the International Cartilage Repair Society classification.

Patella-patellar tendon angle and lateral patella-tilt angle decrease patients with chondromalacia patella

PURPOSE

The aim of the present study was to evaluate the effect of patellofemoral joint morphology and patellar alignment (lateral patellar tilt and sagittal patellar tilt) on the presence and stage of CP, and identify the differences between sexes.

METHODS

MRI of 243 patients [146 men (60.1%)] were evaluated retrospectively. Patients were grouped as normal group without chondromalacia, group with mild chondromalacia (grades 1-2) and group with severe chondromalacia (grades 3-4). Sagittal patellofemoral alignment was assessed by the angle between the patella and patellar tendon (P-PTA), and the angle between the quadriceps tendon and patella (Q-PA). Patellar tilt was assessed by lateral patellar tilt angle (LPTA). In addition, patellofemoral joint morphology was evaluated by measuring trochlear depth (TD), trochlear sulcus angle (TSA) and patella angle (PA).

RESULTS

P-PTA, Q-PA, LPTA and TD values were significantly lower in patients with severe chondromalacia than in patients with both normal and mild chondromalacia (P < 0.001). TSA values were significantly higher in patients with severe chondromalacia than those with both normal and mild chondromalacia (P < 0.001). TSA was higher and TD was lower in women compared to men (P < 0.001). LPTA and P-PTA were lower in women compared to men, and the difference was significant. There was no difference in PA between the two sexes.

CONCLUSIONS

Patellar cartilage degeneration increases with trochlear dysplasia. There is a strong correlation between patellar malalignment (lateral patellar tilt and sagittal patellar tilt) and chondromalacia patella. Women are more prone to developing CP than men.

Assessment of the relationship between patellar volume and chondromalacia patellae using knee magnetic resonance imaging

OBJECTIVE:

In this study, we evaluated the relationship between patellar volume and chondromalacia patellae.

METHODS:

A total of 162 patients who underwent knee magnetic resonance imaging (MR) due to knee pain at our department between January 2017 and May 2017 were included in this study. Of the cases, 111 were chondromalacia patellae, and 51 were healthy individuals. The patella volumes of all cases were analyzed using semi-automated software. Staging in cases with chondromalacia was graded according to the Outerbridge classification (stages 1–4). The relationship between patellar volume, presence of chondromalacia, cartilage thickness, age, and sex was analyzed statistically.

RESULTS:

Of the 162 cases, 67 (41.4%) were male, and 95 (58.6%) were female. The median age of the cases was 44. Patellar volume was a minimum of 12.24, a maximum of 39.44, and a median 21.4 cm³, and it was higher in cases with chondromalacia (p=0.026). In patients with chondromalacia patellae, the thickness of cartilage in the medial facet was lower. There was a statistically significant weak positive correlation between chondromalacia grade and patellar volume (p=0.031, r=0.204).

CONCLUSION:

This study showed that chondromalacia patellae, one of the important causes of chronic frontal knee pain, has a statistically significant relationship with patellar volume. The medial facial cartilage of the patella was thinner than in cases with chondromalacia patellae. Although the mean age of the cases with chondromalacia was higher than the cases without chondromalacia, there was no significant difference between male and female individuals.

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

BACKGROUND

Our 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.

METHODS

We 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.

RESULTS

Mean 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).

CONCLUSIONS

In 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 EVIDENCE

III, case control study.

Clinical mid- to long-term outcome after autologous chondrocyte implantation for patellar cartilage lesions and its correlation with the geometry of the femoral trochlea

BACKGROUND

The aim was to investigate the clinical results after autologous chondrocyte implantation (ACI) at the patella in a mid- to long-term course, and whether trochlear dysplasia has an influence on the outcome.

METHODS

Inclusion criteria were ACI for focal patella cartilage defects and preoperative magnetic resonance imaging (MRI). Patients with previous trochleoplasty or osteotomy have been excluded. Trochlea morphology was evaluated by sulcus depth, sulcus angle, lateral condyle index (LCI) and Dejour's classification for trochlea dysplasia. The clinical outcome was evaluated by a questionnaire including the Kujala- and IKDC-Scores. Survival of the ACI was analysed by the Kaplan-Meier method. A correlation analysis between morphologic parameters and clinical scores was performed.

RESULTS

Seventy-eight patients (mean age 33.2 ± 10.7 years) were included (mean follow-up 6.5 ± 3.4 years). The mean sulcus depth was 5.0 ± 1.6 mm (normal value ≥5 mm), the mean sulcus angle was 153.4 ± 9.0° (normal value ≤145°) and the mean LCI was 84.9 ± 7.5% (normal value ≥90%). Major trochlea dysplasia (grades B-D) was seen in 29 patients (36.7%). Five-year survival rate was 98%, satisfaction-rate was 78.9% and the mean clinical scores were 67.6 ± 20.2 for the Kujala-Score and 64.7 ± 20.2 for the IKDC-Score. A lower LCI showed significant correlation with a lower IKDC score (r = 0.25; p = 0.037).

CONCLUSIONS

The present study reports an excellent survival rate and a good satisfaction rate in a mid- to long-term course after patella ACI. The clinical scores show a high variance and there is evidence that a pathologic trochlea correlates with inferior results.

Degenerative isolated cartilage defects of the patellofemoral joint are associated with more severe symptoms compared to trauma-related defects: results of the German Cartilage Registry (KnorpelRegister DGOU)

PURPOSE

The purpose of this study was to utilize data from the German Cartilage Registry (KnorpelRegister DGOU) to examine the hypothesis that degenerative cartilage defects of the patellofemoral joint are associated with more severe clinical symptoms compared to trauma-related defects.

METHODS

All patients with isolated focal cartilage defects of the patellofemoral joint registered in the German Cartilage Registry until May 2017 were included in the study. Patients with previous surgery of the ipsilateral knee were excluded. Baseline data including etiology (traumatic, degenerative), size, location and ICRS grade of the cartilage defects as well as the duration of symptoms were analyzed. Clinical symptoms were evaluated by means of the numeric analog scale (NAS) for pain and the Knee injury and Osteoarthritis Outcome Score (KOOS). Group comparisons were performed using the Mann-Whitney-U test along with the Chi-squared test and Fisher's exact test. A bivariate correlation analysis and a multivariable linear regression analysis were performed to investigate the association between the defect characteristics and the clinical scores.

RESULTS

A total of 423 patients (203 traumatic and 220 degenerative defects) were included. Isolated degenerative cartilage defects were found to have significantly more trochlear locations (28% vs. 18%; p = 0.006), significantly less ICRS grade 4 lesions (50% vs. 73%; p = 0.002) and a significantly smaller defect size [median 300 (IQR 105-400) vs. 300 (200-400) mm²] when compared to those from traumatic etiology. Traumatic defects showed significantly better KOOS-ADL [77 (60-90) vs. 69 (56-82); p = 0.005], KOOS-pain [69 (56-81) vs. 61 (47-75); p = 0.001] and NAS [2 (1-5) vs. 4 (1-6); p = 0.005] scores compared to degenerative defects. The correlation analysis revealed only weak correlations between the quantitative defect characteristics and clinical scores.

CONCLUSIONS

Degenerative isolated cartilage defects in the patellofemoral joint are associated with more severe clinical symptoms in comparison to trauma-related defects. Additionally, they show a larger variance regarding their location with more trochlear defects.

LEVEL OF EVIDENCE

III.

Chondromalacia Patella among Military Recruits with Anterior Knee Pain: Prevalence and Association with Patellofemoral Malalignment

BACKGROUND

The aim of this study was to investigate the frequency of chondromalacia patella (CMP) and to evaluate its relation with trochlear morphometric and patellofemoral alignment measurements as well as with edema in superolateral region of Hoffa's fat pad (SHFP) in military recruits with anterior knee pain (AKP).

MATERIALS AND METHODS

Knee magnetic resonance imaging examinations of 288 military recruits with AKP were retrospectively evaluated. Patellar cartilage lesions were graded using modified Noyes system. Quantitative measurements of trochlear morphology (sulcus angle, trochlear sulcus depth, and lateral trochlear inclination [LTI]) and patellofemoral alignment (patellar translation [PT], lateral patellofemoral angle (LPA), Insall-Salvati index, and tibial tuberosity-trochlear groove distance) were made. The SHFP region was assessed for the presence of edema. Mean values of measurements in knees with and without CMP and in knees with early and advanced stage CMP were compared.

RESULTS

We found CMP in 169 (58.7%) patients. Patients with CMP demonstrated a significantly greater sulcus angle (P = 0.012), smaller LTI (P = 0.004), greater PT (P = 0.01), smaller LPA (P = 0.036), greater Insall-Salvati ratio (P = 0.034), and higher incidence of SHFP edema (P = 0.001) compared to those without CMP. While none of the measurements were associated with the severity of cartilage damage, the incidence of SHFP edema was significantly correlated with the severity of CMP (P = 0.001).

CONCLUSION

CMP is a common disorder among military recruits with AKP. Patellofemoral malalignment is an important contributory factor in the development of CMP, and the presence of edema in SHFP may be a strong indicator of underlying severe CMP in this population.

Evaluation of Trochlear Dysplasia Severity Using Trochlear Angle: A Retrospective Study Based on Computed Tomography (CT) Scans

Background

Trochlear dysplasia is an important pathological factor in patellofemoral instability. Quantitative evaluation of the severity of trochlear dysplasia is rare and remains unclear.

Material/Methods

Computed tomography (CT) data on 136 knees (95 patients) with trochlear dysplasia in the case group and an age- and sex-matched cohort of 120 knees (70 patients) in the control group were collected for this retrospective study. All participants had undergone CT scans in the supine position. The trochlear angles (TA) formed by the posterior condylar line and the trochlear line were calculated and compared. The threshold for statistical significance was set at p<0.05.

Results

The mean TA values were significantly greater in the case group compared to the control group independent of sex (p<0.01). The distribution of trochlear dysplasia of Dejour grades was type A n=34, type B n=31, type C n=40, and type D n=31. Except for types A and B, differences in the trochlear dysplasia grade between any 2 other types were statistically significant (p<0.01).

Conclusions

The technique of measuring TA is reproducible and accurate in patients with patellar instability and normal controls. The TA positively correlates with higher levels of trochlear dysplasia. This technique can help to evaluate and treat trochlear dysplasia in research as well as in clinical practice.

Patellofemoral pain in athletes: clinical perspectives

Patellofemoral pain (PFP) is a very common problem in athletes who participate in jumping, cutting and pivoting sports. Several risk factors may play a part in the pathogenesis of PFP. Overuse, trauma and intrinsic risk factors are particularly important among athletes. Physical examination has a key role in PFP diagnosis. Furthermore, common risk factors should be investigated, such as hip muscle dysfunction, poor core muscle endurance, muscular tightness, excessive foot pronation and patellar malalignment. Imaging is seldom needed in special cases. Many possible interventions are recommended for PFP management. Due to the multifactorial nature of PFP, the clinical approach should be individualized, and the contribution of different factors should be considered and managed accordingly. In most cases, activity modification and rehabilitation should be tried before any surgical interventions.

Arthroscopic deepening trochleoplasty for chronic anterior knee pain after previous failed conservative and arthroscopic treatment. Report of two cases

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This study acknowledge that chronic anterior knee pain or patellofemoral can be caused based on trochlear dysplasia.

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The paper discuss the scientific background for this.

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By restoring the patient anatomy performing an arthroscopic trochleoplasty, the patients anterior knee pain was reduced significantly.

Purpose

A proportion of patients having years of chronic anterior knee pain(AKP) that have not responded to non-operative modalities. Trochlear dysplasia have been found to be a cause for AKP. By restoring the anatomy with a trochleoplasty procedure the patellofemoral joint is unloaded. This study is a prospective 2 year follow-up study, based on two cases with chronic AKP for several years and having severe trochlear dysplasia and both were successfully treated by arthroscopic deepening trochleoplasty.

Methods

Case one was a 46 year old women with chronic anterior knee pain (AKP). Imaging showed lateral trochlear inclination angle of 2°, trochlear asymmetry 0.36, central height 81% and medial height 83%. Thepreoperative Kujala score was 70 and Knee injury and Osteoarthritis Outcome Score (KOOS) subscale for pain was 67. Case two was a 26 year old man troubled by AKP and knee knee joint effusion for >8 years without any instability in the history. Imaging showed lateral trochlear inclination angle of 6°, trochlear asymmetry 0.25, central height 76% and medial height 78%. The preoperative Kujala score was 49 and KOOS subscale for pain was 72.

Results

The postoperative Kujala score was for case one 82 and for case two 81. The postoperative KOOS subscale for pain was for case one 89 and for case two 92. Improvement in the KOOS subscale for sport and recreational activities and quality of living were also found.

Conclusion

This is the first case report to demonstrate that patient having had years of chronic AKP and trochlear dysplasia can be successfully treated by arthroscopic trochleoplasty.