Search Results (18)

Background: Primary patellar dislocation is a relatively uncommon knee injury but carries a high risk of recurrence, particularly in young and physically active adolescent individuals. Anatomical features of the patellofemoral joint have been implicated as key contributors to instability. The purpose of this study was to evaluate anatomical risk factors associated with recurrent patellar dislocation following a primary traumatic event, using MRI-based parameters. Methods: Fifty-four patients who sustained a first-time lateral patellar dislocation were included. MRI was used to measure tibial tuberosity–trochlear groove (TT–TG) distance, tibial tuberosity–posterior cruciate ligament (TT–PCL) distance, Insall–Salvati ratio (IS), sulcus angle (SA), patellar tilt angle (PTA), patella length, and patellar tendon length. Trochlear dysplasia was assessed according to the Dejour classification. Recurrence was defined as a subsequent dislocation occurring within three years of the primary injury. Results: Significant differences were observed in TT–TG distance and patellar tendon length (p < 0.05). Patients with recurrent dislocation had lower TT–TG values and shorter patellar tendon lengths. Other parameters, including PTA, IS, and patella height, did not show statistically significant differences. Conclusion: Anatomical factors may contribute to the risk of recurrent patellar dislocation. Identifying these variables using imaging may support clinical decision making and guide individualized treatment plans following primary injury. Full article

Background/Objectives: The diagnostic guidelines for pediatric patellofemoral instability (PFI) remain incomplete. PFI remains a challenging issue as it affects the biomechanics of the knee joint, triggers anterior knee pain, and is linked to the development of early-onset osteoarthritis. The diagnostic process is complicated by numerous anatomical factors that must be considered. This review aims to consolidate current knowledge presented in the literature on radiological diagnostics for PFI in pediatric populations, with the application of all imaging techniques—including ultrasonography (US), magnetic resonance imaging (MRI), computed tomography (CT), and radiography (RTG)—which enable the evaluation of anatomical risk factors critical for the diagnosis, prevention, and treatment of PFI. Methods: A search of the PubMed/MEDLINE database was conducted to identify relevant studies from 1975 to 2024. The search terms were as follows: (patellar or patella) and (instability or displacement or dislocation) and (diagnostic or diagnosis or imaging or radiographic). A total of 2743 articles were retrieved, which were screened to yield 29 studies for further review. These studies were then divided into seven categories regarding the diagnostic methods: risk factors, tibial tubercle trochlear groove (TT-TG)/tibial tubercle posterior cruciate ligament (TT-PCL), MPFL injury and cartilage damage, patella and trochlear dysplasia, torsional abnormalities, coronal plane alignment, and genetics. Results: The methods presented statistically significant differences, with those most commonly used for the diagnosis of patella dislocation being TT-TG index, MPFL rapture, and trochlear dysplasia. Conclusions: In summary, multiple diagnostic tools, including MRI, CT, X-ray, and physical examination, are available for the assessment of PFI, each contributing to treatment decisions. Although MRI remains the primary diagnostic tool, further research is needed to establish more precise diagnostic criteria. Full article

Abnormal trochlear morphology is one of the most important factors for patellar luxation occurrence in dogs, yet no studies have investigated its prevalence in the general population. This retrospective computed tomography study was designed to evaluate the trochlear groove morphology in four small dog breeds and the prevalence of trochlear dysplasia types according to Déjour’s classification depending on the breed, sex, and medial patellar luxation (MPL) presence and grade. A total of 174 joints (68 healthy, 96 grade II MPL, and 10 grade III MPL) from Mini-Pinschers, Yorkshire Terriers, Pomeranians, and Chihuahuas were included in the study. The morphological type of trochlear dysplasia (TD) was evaluated on axial scans and 3D reconstruction images according to the four-type classification of Déjour, sulcus angle, trochlear depth, and lateral/medial inclination angles. Of all 174 joints, 140 had trochlear dysplasia—all joints with MPL (n = 106) and 50% of healthy joints (n = 34). The classification of Déjour for trochlear dysplasia types (A, B, C, and D) corresponds to the morphology of the femoral trochlea in the studied small breeds of dogs. The results demonstrated three types of trochlear dysplasia according to Déjour: most commonly, type A, followed by type C, and most infrequently, type D. The Déjour type B was an incidental finding. The large proportion of clinically healthy joints with TD (50%) emphasises the significance of early trochlear morphology evaluation for the orthopaedical health of dogs from susceptible breeds, especially in female breeders. Full article

Patellar pathologies are a common cause of knee dysfunction, with Patellofemoral Pain Syndrome (PFPS) alone responsible for 25% of knee-related visits to sports medicine clinics. Non-traumatic conditions, while often overlooked, can also lead to significant discomfort and functional limitations, highlighting the importance of accurate and timely diagnosis for effective management and prevention of complications. This pictorial review examines the radiologic characteristics of various non-traumatic patellar disorders, focusing on imaging modalities such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Key diagnostic markers, including patellar tilt, tibial tuberosity–trochlear groove distance (TT-TG), and congruence angle (CA), are discussed for their significance in non-traumatic pathology identification. Furthermore, this review highlights specific radiologic features for a range of non-traumatic patellar conditions, including patellar tendinopathy, chondromalacia patellae, and trochlear dysplasia, emphasizing how distinct radiologic findings facilitate precise diagnosis and clinical assessment. Ultimately, it provides a practical guide for clinicians in diagnosing non-traumatic patellar pathologies through a comprehensive review of key radiologic features while also discussing advancements in imaging technologies and management strategies to support accurate diagnosis and effective clinical decision-making. Full article

Background: Patella instability is one of the most common knee injuries in the adolescent patient. There are several pathoanatomic risk factors which should be assessed via several modalities, including X-rays, magnetic resonance imaging (MRI), or even CT scan. Objectives: We intend to review these risk factors along with the nonsurgical and surgical techniques used to prevent recurrent dislocations. Methods: We completed an extensive review of the recent literature concerning pediatric and adolescent patellar dislocation and subsequent treatment modalities. Results: We review in detail the risk factors such as patella alta, trochlear dysplasia, lateralization of the tibial tubercle or medialization of the trochlear groove (increased tibial tubercle to trochlear groove (TT–TG) distance), lower limb malalignment, excessive femoral anteversion and/or tibial torsion, and hyperlaxity. There are classification systems for dislocators, and a natural progression of instability that patients often proceed through. Only after a patient has continued to dislocate after bracing and physical therapy is surgical treatment considered. Surgical techniques vary, with the workhorse being the medial patellofemoral ligament (MPFL) reconstruction. However, there are a variety of other techniques which add onto this procedure to address other anatomic risk factors. These include the tibial tubercle osteotomy to address a large TT–TG distance or trochleoplasty to address the lack of a trochlear groove. Conclusions: Nonsurgical and surgical treatments for patella dislocators are tailored to the pathoanatomic risk factors in each patient. Full article

Background and Objectives: This study aimed to evaluate the tibial tubercle–posterior intercondylar eminence (TT-IC) distance as a diagnostic tool and surgical guide for correcting extensor apparatus misalignment through tibial tubercle osteotomy. Materials and Methods: A retrospective analysis was conducted on patients with extensor apparatus misalignment. The TT-IC distance was measured using MRI. Patients underwent tibial tubercle osteotomy, guided by the TT-IC distance for correction. Post-operative outcomes, including alignment, pain scores, and functional recovery, were assessed. Results: A significant correlation was found between the TT-IC distance and the degree of extensor apparatus misalignment. Utilizing the TT-IC distance as a surgical guide led to improved alignment in majority of patients. Post-operative outcomes showed reduced pain and enhanced functional recovery. Conclusions: The study established the TT-IC measurement as a valuable tool for determining the need for tibial tuberosity osteotomy in patients with patellar instability, particularly those with trochlear dysplasia, by providing a more precise criterion than the traditional TT-TG distance. Full article

Background: Literature is sparse on outcome comparisons between different trochleoplasty techniques in the treatment of patella instability. To date, it is unclear whether there is a technique that offers superior outcomes. This systematic review and meta-analysis aims to compare and evaluate the outcomes of trochleoplasty techniques in the treatment of patellofemoral instability in trochlea dysplasia to establish whether there is an ideal choice of trochleoplasty technique for superior outcomes. Methods: 21 studies involving 880 knees were included. The mean age of the patients was 21.7 years (range 8–49 years). Mean follow-up timeframe of 43.5 months (range 8.8–100 months). Clinical outcomes assessed included rates of recurrence of patellofemoral dislocation, patient satisfaction, Kujala score, International Knee Documentation Committee (IKDC) score, Tegner score, and Lysholm score. Egger’s test showed no publication bias across all outcomes assessed. Results: Favourable results were seen across all outcomes assessed and patient satisfaction. Improvements were seen with Kujala, IKDC, and Lysholm scores. Tegner scores showed good return to function. Post-operative dislocation and complication rates were low across the different techniques. Meta-regression for Kujala and IKDC scores showed good outcomes regardless of trochleoplasty technique used (Kujala, p = 0.549, relative risk 492.06; IKDC, p = 0.193, RR 0.001). The exact risk that trochleoplasty poses to the cartilage remains uncertain, as no study had a conservatively managed arm for comparison. Conclusions: Trochleoplasty yielded good outcomes irrespective of technique used with no clear superiority demonstrated in any technique in terms of outcome scores, satisfaction, post-operative dislocation rates or complications. Full article

Background: The intercondylar notch (ICN) and the anterior cruciate ligament (ACL) are important structures in knee morphometry, with key roles in stabilizing the knee. Aim: To determine the associations between the specific shape of the ICN (A-, W-, or U-shape) and the ACL size in patients with intact ACLs. Methods: Magnetic resonance imaging (MRI) scans were independently analyzed by two experts: one orthopedic surgeon and one imaging physician. In all cases, the following measurements were taken based on the existing definitions: ACL area, anterior ICN (aICN) area, ICN width, lateral trochlear inclination (LTI), and Insall–Salvati index. Results: A total of 65 cases (50.8% male; 33.8 ± 10.2 years mean age at inclusion) were included in the study. The ACL and aICN areas were significantly larger in patients with U-shaped compared with A-shaped and W-shaped ICNs: 0.50 (0.20–0.80) vs. 0.40 (0.20–0.80) vs. 0.40 (0.30–0.80), p = 0.011 and 1.16 (0.57–3.60) vs. 0.47 (0.15–0.95) vs. 0.37 (0.15–0.81), p < 0.001, respectively. Internal meniscal lesions were more common in cases with U-shaped ICNs (64.0%), while external ones were more common in W-shaped ICN cases (35.3%). None of the A-shaped cases had external chondral or meniscal lesions. The ACL area was significantly larger in males and internal meniscal injuries, with no differences between chondral lesions, external meniscal injuries, patellar chondral lesions, patella alta, or trochlear dysplasia. Conclusion: The specific shape of the intercondylar notch was associated with the anterior cruciate ligament–anterior intercondylar notch (ACL–aICN) area size correlation, with a strong correlation between ACL and aICN area when the intercondylar notch was A-shaped or W-shaped, and a low correlation when the notch was U- shaped. The specific shape of the intercondylar notch (A-, W-, or U-shape) was associated with the occurrence of both internal and external meniscal injuries, with the U-shaped intercondylar notch morphometry being more frequent in cases with internal meniscal injuries and the W-shape being more common in cases with external meniscal injuries. Full article

Patellofemoral instability is a prevalent cause of pain and disability in young individuals engaged in athletic activities. Adolescents face a particularly notable risk of patellar dislocation, which can be attributed to rapid skeletal growth, changes in q-angle, ligamentous laxity, higher activity levels, and increased exposure to risk. Specific sports activities carry an elevated risk of patellar dislocation. Younger age and trochlear dysplasia present the highest risk factors for recurrent patellar dislocations. International guidelines recommend conservative therapy following a single patellar dislocation without osteochondral lesions but suggest surgical intervention in recurrent cases. In this study, we have compiled current scientific data on therapy recommendations, focusing on MPFL (medial patellofemoral ligament) reconstruction. We discuss patient selection, surgical indications, graft selection, location and choice of fixation, graft tensioning, and postoperative care. Full article

The patellofemoral joint (PFJ) is a complex articulation between the patella and the femur which is involved in the extensor mechanism of the knee. Patellofemoral disorders can be classified into objective patellar instability, potential patellar instability, and patellofemoral pain syndrome. Anatomical factors such as trochlear dysplasia, patella alta, and the tibial tuberosity–trochlear groove (TT-TG) distance contribute to instability. Patellofemoral instability can result in various types of dislocations, and the frequency of dislocation can be categorized as recurrent, habitual, or permanent. Primary patellar dislocation requires diagnostic framing, including physical examination and imaging. Magnetic resonance imaging (MRI) is essential for assessing the extent of damage, such as bone bruises, osteochondral fractures, and medial patellofemoral ligament (MPFL) rupture. Treatment options for primary dislocation include urgent surgery for osteochondral fragments or conservative treatment for cases without lesions. Follow-up after treatment involves imaging screening and assessing principal and secondary factors of instability. Detecting and addressing these factors is crucial for preventing recurrent dislocations and optimizing patient outcomes. Full article

A shallow sulcus characterizes trochlear dysplasia (TD) of the femoral trochlea, which can lead to chronic pain or instability of the patellofemoral joint. Breech presentation at birth has been identified as a risk factor for developing this condition, which an ultrasound can identify early. Early treatment could be considered at this stage, given the potential for remodelling in these skeletally immature patients. Newborns with breech presentation at birth who meet the inclusion criteria will be enrolled and randomised in equal proportions between treatment with the Pavlik harness and observation. The primary objective is to determine the difference in the means of the sulcus angle between the two treatment arms at two months. Ours is the first study protocol to evaluate an early non-invasive treatment for TD in the newborn with breech presentation at birth using a Pavlik harness. We hypothesised that trochlear dysplasia could be reverted when identified and treated early in life with a simple harness, as it is done with developmental dysplasia of the hip. Full article

Background and Objectives: Various predisposing factors for lateral patellar dislocation (LPD) have been identified, but the relation between femoral rotational deformity and the tibial tubercle–Roman arch (TT-RA) distance remains elusive. Materials and Methods: We conducted this study including 72 consecutive patients with unilateral LPD. Femoral anteversion was measured by the surgical transepicondylar axis (S-tAV), and the posterior condylar reference line (P-tAV), TT-RA distance, trochlear dysplasia, knee joint rotation, patellar height, and hip–knee–ankle angle were measured by CT images or by radiographs. The correlations among these parameters were analyzed, and the parameters were compared between patients with and without a pathological TT-RA distance. Binary regression analysis was performed, and receiver operating characteristic curves were obtained. Results: The TT-RA distance was correlated with S-tAV (r = 0.360, p = 0.002), but the correlation between P-tAV and the TT-RA distance was not significant. S-tAV had an AUC of 0.711 for predicting a pathological TT-RA, with a value of >18.6° indicating 54.8% sensitivity and 82.9% specificity. S-tAV revealed an OR of 1.13 (95% CI [1.04, 1.22], p = 0.003) with regard to the pathological TT-RA distance by an adjusted regression model. Conclusions: S-tAV was significantly correlated with the TT-RA distance, with a correlation coefficient of 0.360, and was identified as an independent risk factor for a pathological TT-RA distance. However, the TT-RA distance was found to be independent of P-tAV. Full article

Background: The aim of this study was to determine whether traumatic dislocation of the patella is provoked by the presence of predisposing factors and examine the role of the mechanism of injury. Methods: Cases diagnosed with dislocation of the patella and covered by the workers’ compensation program were identified and classified as traumatic based on insurance regulations. We examined predisposing factors (e.g., frontal axis, torsional deviation, trochlear dysplasia, patella alta) in case groups based on age at dislocation and trauma mechanism. Retrospective cohort study, level of evidence III. Results: Our sample size comprised 104 cases, consisting of 54 children and 50 adults. The most common mechanism of injury in children and adults was rotational trauma. Only 20% of the children and 21% of the adults exhibited no relevant predisposing factors. Group specifically, falls accounted for the highest number of cases exhibiting none of the defined anatomical predisposing factors. Children are more frequently affected by predisposition-related dislocations than adults. Conclusion: The proportion of predispositions is high. A fall, direct impact, or rotational trauma can be viewed as an adequate mechanism of trauma. For successful treatment, it is paramount to analyze the exact mechanism of the trauma and address any underlying predispositions. Full article

Introduction: The influence of the MPFL graft in cases of patella instability with dysplastic trochlea is a controversial topic. The effect of the MPFL reconstruction as single therapy is under investigation, especially with severely dysplastic trochlea (Dejour types C and D). The purpose of this study was to evaluate the impact of trochlear dysplasia on patellar kinematics in patients suffering from low flexion patellar instability under weight-bearing conditions after isolated MPFL reconstruction. Material and Methods: Thirteen patients were included in this study, among them were eight patients with mild dysplasia (Dejour type A and B) and five patients with severe dysplasia (Dejour type C and D). By performing a knee MRI with in situ loading, patella kinematics and the patellofemoral cartilage contact area could be measured under the activation of the quadriceps musculature in knee flexion angles of 0°, 15° and 30°. To mitigate MRI motion artefacts, prospective motion correction based on optical tracking was applied. Bone and cartilage segmentation were performed semi-automatically for further data analysis. Cartilage contact area (CCA) and patella tilt were the main outcome measures for this study. Pre- and post-surgery measures were compared for each group. Results: Data visualized a trending lower patella tilt after MPFL graft installation in both groups and flexion angles of the knee. There were no significant changes in patella tilt at 0° (unloaded pre-surgery: 22.6 ± 15.2; post-surgery: 17.7 ± 14.3; p = 0.110) and unloaded 15° flexion (pre-surgery: 18.9 ± 12.7; post-surgery: 12.2 ± 13.0; p = 0.052) of the knee in patients with mild dysplasia, whereas in patients with severe dysplasia of the trochlea the results happened not to be significant in the same angles with loading of 5 kg (0° flexion pre-surgery: 34.4 ± 12.1; post-surgery: 31.2 ± 16.1; p = 0.5; 15° flexion pre-surgery: 33.3 ± 6.1; post-surgery: 23.4 ± 8.6; p = 0.068). CCA increased in every flexion angle and group, but significant increase was seen only between 0°–15° (unloaded and loaded) in mild dysplasia of the trochlea, where significant increase in Dejour type C and D group was seen with unloaded full extension of the knee (0° flexion) and 30° flexion (unloaded and loaded). Conclusion: This study proves a significant effect of the MPFL graft to cartilage contact area, as well as an improvement of the patella tilt in patients with mild dysplasia of the trochlea. Thus, the MPFL can be used as a single treatment for patient with Dejour type A and B dysplasia. However, in patients with severe dysplasia the MPFL graft alone does not significantly increase CCA. Full article

Background: The tibial tubercle to trochlear groove (TT-TG) distance is currently considered as an indication for tibial tubercle osteotomy. While the influence of femoral condylar morphology on such measurement remains unclear. Methods: A total of 86 patients with patellar dislocation (PD) and 86 healthy individuals were enrolled. Femoral condylar morphology and the TT-TG distance measured by anatomical transepicondylar axis (TT-TGa), by surgical transepicondylar axis (TT-TGs), and by posterior condylar reference line (TT-TGp) were assessed by MRI. Unpaired t-test, Spearman, and Pearson correlation analysis were conducted. We determined the pathological value of the parameters and established a binary regression model. Results: The interclass correlation coefficients of all the TT-TG distances were greater than 0.75 in all types of trochlear dysplasia. The lateral/posterior femoral condyle was shorter and the medial/posterior condyle was longer in the study group (28.5 ± 3.3 and 35.2 ± 2.8, respectively) than in the control group (30.9 ± 2.7 and 33.5 ± 2.3, respectively). In the study group, the TT-TGp distance was greater than TT-TGs and TT-TGa distance (p < 0.001). The pathological value of the TT-TG distance was 13.0 mm. Each TT-TG distance revealed a significant OR with regard to PD. Conclusion: The TT-TGa, TT-TGs, and TT-TGp distance can be reliably measured by MRI even in patients with trochlear dysplasia. While the TT-TGp distance may overestimate the lateralization deformity of the tibial tubercle. Posterior femoral condylar dysplasia may be a reason for such overestimating. These findings have not been correlated to clinical outcomes and further studies are required. Full article