Lateral Patellar Tilt Angle Research Articles

Arthroscopic medial patellofemoral ligament reconstruction with polyethylene suture combined with medial retinaculum plication for the treatment of acute patellar dislocation in young and middle-aged patients with a follow-up of at least 2 years

PurposeThe purpose of this study was to propose a surgical technique for arthroscopic medial patellofemoral ligament (MPFL) reconstruction with polyethylene suture combined with medial retinaculum plication and to evaluate the efficacy of this surgical technique in the treatment of acute patellar dislocation.MethodsClinical data of patients with acute patellar dislocations treated with arthroscopic MPFL reconstruction with polyethylene tape (FiberTape) combined with medial support band compression were analyzed retrospectively from January 2018 to January 2021. The mean age of the patients was 25.15 ± 4.66 years; the mean follow-up time was 27.5 (24–36) months. Clinical evaluation consisted of apprehension test results, patellar extrapolation test results, Lysholm score, Kujala score, and IKDC score, the Patellar lateral shift distance and patellar tilt angle (PTA) measured by CT scan.ResultsAll patients had no recurrent patellar dislocation or subluxation after surgery, and the apprehension test was negative. In all patients, the Kujala score (36.0 ± 9.9 vs. 98.2 ± 3.1), the IKDC score (48.6 ± 7.0 vs. 90.6 ± 4.4) and the Lysholm score (32.8 ± 10.4 vs. 96.7 ± 3.1) had improved at the 24-month follow up (P < 0.05). In addition, PTA was significantly lower at the 12-month follow-up and 24-giving-month follow-up compared to the preoperative period (P < 0.05, Table 2). The patellar lateral shift distance decreased from 14.94 ± 6.11 mm preoperatively to 3.00 ± 1.40 mm (12-month follow up) and 3.26 ± 1.37 mm (24-month follow up), respectively.ConclusionArthroscopic MPFL reconstruction with polyethylene suture combined with medial retinaculum plication is a safe and reliable surgical technique for the treatment of acute patellar dislocation in young and middle-aged patients.Level of EvidenceLevel III, Therapeutic Study.

Correlating quadriceps patellar tendon angle and lateral patellar tilt angle in patients with irregular alignment: a cross-sectional study with retrospective data.

The newly defined angle, quadriceps-patella angle (QPA), reflects the combined force transmitted to the patella by the quadriceps muscles and patellar tendon. An increase in QPA may correlate with an increased force on the patella, which is significant in diagnosing patellofemoral instability and pain syndrome. In our study, we examined how various angles and pathologies vary depending on lateral patellar tilt angle (LPTA). QPA and patellar malalignment was investigated. Thus, the importance of understanding patellar malalignment and the research gap. Three hundred and fifty patients who underwent knee magnetic resonance imaging (MRI) examinations were included. The cross-sectional study conducted retrospectively between the years of 2018-2020 in a tertiary care outpatient clinic. Shapiro-Wilk normality, Chi-square, Mann-Whitney-U, Spearman correlation and receiver operating characteristic (ROC) curve analysis, statistical tests used for analysis. The patellar tendon length, patellar height, tibial tubercle-trochlear groove distance (TT-TG), patella angle, trochlear sulcus angle, trochlear groove depth (TGD), medial trochlea length (MT), lateral trochlea length (LT), medial trochlear/lateral trochlear length ratio (MT/LT), LPTA, patella-patellar tendon angle (PPTA), QPA, Insall-Salvati index (ISI), medial trochlear inclination (MTI), lateral trochlear inclination (LTI) were among these measurements. In addition, we aim to reveal whether there is a significant relationship between two important angles LPTA and QPA. Whether there is a significant increase in the development of chondromalacia for the patient group with LPTA >5°. We examined how the frequency of chondromalacia changes in the patient group with LPTA >5°. Two hundred and seventy seven patients included in the study and many measurements were performed on MRI. Fad-pad edema was found to be significantly higher in the group with LPTA <5° (P=0.046). TT-TG distance was significantly higher, TGD and MT were significantly lower in patients with higher LPTA (P=0.001, P=0.002 and P=0.017, respectively). A low level of significant positive correlation was found between QPA and patellar tendon length. There is no significant difference between QPA and PPTA angles between the groups with LPTA <5° and >5° (P=0.503, P=0.188). In the ROC analysis performed to determine the cut-off value, the LPTA value ≤14.2° which significantly predicted the presence of fad-pad edema, had the highest sensitivity and specificity [sensitivity: 76.71%, specificity: 39.90%, area under the curve (AUC): 0.588, P=0.024]. QPA is independent from many angles of the knee and does not change significantly. As the patellar tendon length increases, QPA angle also increases. In patients with abnormal LPTA, the frequency of TT-TG distance and chondromalacia increased, while TGD and MT decreased. Patients with a low LPTA can be more carefully examined for chondromalacia and fad-pad edema in clinical and MRI examination.

Femoropatellar alterations in knees with chronic anterior cruciate ligament injuries: a radiographic analysis

Background: The objective of this study was to correlate the occurrence of patellofemoral malalignment in a chronic anterior cruciate ligament (ACL) deficient knee using common radiological parameters. Methods: A case-control study was conducted on 35 adult patients with previously diagnosed unilateral chronic ACL injury. The injured knee was considered as the case, while the contralateral normal knee served as the control. Radiological parameters including the Caton-Deschamps patellar height index, Merchant patellar congruence angle, and Laurin lateral patellar tilt angle were measured on X-rays obtained from both normal and ACL injured knees. A comparative analysis was performed between the two groups. Results: The Caton-Deschamps patellar height index had a mean value of 0.95±0.05 in the ACL-deficient knee. The Merchant patellar congruence angle showed mean values of 12.66±0.84 degrees in the ACL injured knee, while the Laurin lateral patellar tilt angle was 8.06±1.41 degrees in knees with ACL failure. These results indicate lower patellar height, greater lateral displacement of the patella, and increased lateral patellar tilt in knees with chronic ACL tears, thereby affecting the patellofemoral joint. Conclusions: Chronic ACL tears are associated with patellofemoral malalignment, characterized by decreased patellar height, increased lateral displacement of the patella, and greater lateral patellar tilt, thus impacting the patellofemoral joint.

Effect of open-wedge high tibial osteotomy and lateral patellofemoral retinacular release on patellar position: an X-ray imaging-based comparative study.

Open-wedge high tibial osteotomy (OWHTO) may cause adverse changes in the mechanical environment of the patellofemoral joint. For patients with lateral patellar compression syndrome or patellofemoral arthritis, intraoperative management is still challenging. The effect of lateral retinacular release (LRR) on patellofemoral joint mechanics after OWHTO remains unclear. Our study aimed to evaluate the effect of OWHTO and LRR on the patellar position based on lateral and axial radiographs of the knee joint. The study comprised 101 knees (OWHTO group) undergoing OWHTO alone and 30 knees (LRR group) undergoing OWHTO and concomitant LRR. The following radiological parameters were statistically analyzed preoperatively and postoperatively: femoral tibial angle (FTA), medial proximal tibial angle (MPTA), weight-bearing line percentage (WBLP), Caton-Deschamps index (CDI), Insall-Salvati index (ISI), lateral patellar tilt angle (LPTA), and lateral patellar shift (LPS). The follow-up duration ranged from 6 to 38 months, with a mean of 13.51±6.84 months in the OWHTO group and 12.47±7.81 months in the LRR group. The Kellgren-Lawrence (KL) grading system was used to evaluate changes in patellofemoral osteoarthritis (OA). Regarding the patellar height, preliminary analysis demonstrated a statistically significant decrease in the CDI and ISI in both groups (P<0.05). However, there was no significant difference in changes in CDI or ISI between the groups (P>0.05). In the OWHTO group, although there was a significant increase in the LPTA (P=0.033), the postoperative decrease in the LPS was not significant (P=0.981). In the LRR group, both the LPTA and LPS significantly decreased postoperatively (P=0.000). The mean changes in LPS were 0.03 mm in the OWHTO group and 1.44 mm in the LRR group, indicating a significant change in LPS (P=0.000). However, there was no significant difference in changes in LPTA between the groups, which was contrary to our expectations. Imaging showed no change in patellofemoral OA in the LRR group and progressive changes (from KL grade I to II) in patellofemoral OA in 2 (1.98%) patients in the OWHTO group. OWHTO can cause a significant decrease in patellar height and an increase in lateral tilt. LRR can significantly improve the lateral tilt and shift of the patella. The concomitant arthroscopic LRR should be considered for the treatment of patients with lateral patellar compression syndrome or patellofemoral arthritis.

Medial patellofemoral ligament reconstruction in skeletally immature patients without correction of bony risk factors leads to acceptable outcomes but higher failure rates

ObjectivesTo report outcomes and re-dislocation rates of medial patellar stabilizers reconstruction without bone procedures for correction of anatomical risk factors for patellar instability in skeletally immature patients; to compare isolated medial patellofemoral ligament (MPFL) reconstruction to combined MPFL and medial patellotibial ligament (MPTL) reconstruction in this population. MethodsPatients with open physis and bone abnormalities including patella alta and/or increased tibial tubercle-trochlear groove (TT-TG) distance and/or trochlear dysplasia underwent MPFL reconstruction, either isolated or associated with MPTL reconstruction. Preoperative, 1-year follow-up and the latest follow-up (5 years minimum) data were collected. Radiological and clinical evaluations were conducted, with special attention to failure rate. Comparison of results from isolated MPFL and combined MPFL/MPTL reconstructions was performed. ResultsTwenty-nine patients were included, 19 in the isolated MPFL group (median 14 years old; follow-up 5.8 ​± ​1.7 years) and 10 in the combined MPFL/MPTL group (median 13.5 years old; follow-up 5.2 ​± ​1.4 years). Kujala and Tegner scores increased over time, although without statistically significant differences between the two groups at the latest follow-up (p ​= ​0.840 and p ​> ​0.999, respectively). During follow-up, 5 of 19 (26.3%) isolated MPFL and 2 of 10 (20%) MPFL/MPTL reconstructions experienced recurrence of patellar dislocation (p ​> ​0.999). Trochlear dysplasia type D (p ​= ​0.028), knee rotation (p ​= ​0.009) and lateral patellar tilt angle (p ​= ​0.003) were associated with patellar instability recurrence. The isolated MPFL group showed increased laxity on physical exam at the latest follow-up compared to the 1-year follow-up (patellar glide test (p ​= ​0.002), patellar tilt test (p ​= ​0.042) and subluxation in extension (p ​= ​0.019). This increased laxity was not observed in the MPFL/MPTL group (p ​> ​0.999). Comparing both groups, the glide test was significantly better in the combined MPFL/MPTL group in comparison to the isolated MPFL reconstruction group at the latest follow-up (p ​= ​0.021). ConclusionMPFL reconstruction in isolation or combined with MPTL reconstruction in skeletally immature patients with additional uncorrected anatomical patellofemoral abnormalities leads to acceptable clinical outcomes within a minimum of 5 years follow-up, although has a high failure rate of 24.1%. Addition of a MPTL reconstruction to the MPFL may result in decreased patellar laxity on physical exams, as demonstrated by better patellar glide test, patellar tilt test and subluxation in extension. Level of evidenceLevel III; retrospective cohort study.

Evaluation of Anatomical Variations with Morphological Measurements and Their Relationship to Meniscal Injury and Ligament Damage.

The purpose of this study was to reveal the anatomical risk factors for anterior and posterior cruciate ligament (ACL and PCL) injuries and menisci injury. We aim to investigate whether there are significant relationships between tibial tubercle-trochlear groove (TT-TG) distance, patella angle, trochlear sulcus angle (TSA), trochlear groove depth (TGD), medial and lateral trochlea length (MT and LT), MT/LT ratio, lateral patellar tilt angle (LPTA), patella-patellar tendon angle (P-PTA), quadriceps-patellar tendon angle (QPA), Insall-Salvati index (ISI), medial and lateral trochlear inclination (MTI and LTI) measurements and important common pathologies such as ACL, PCL, medial and lateral meniscal injuries (MM and LM), peripatellar fat pad edema, chondromalacia, and effusion. Thus, the mechanisms of injury will be better understood by revealing important anatomical variations for meniscus and ligament damage. Three hundred eighty patients with knee magnetic resonance imaging examination were included in this study. Our patients who underwent knee magnetic resonance imaging were divided into groups according to the presence of MM tear, LM tear, ACL tear, PCL tear, peripatellar fat pad edema, chondromalacia and effusion. TT-TG distance, patella angle, TSA, TGD, MT, LT, MT/LT ratio, LPTA, P-PTA, QPA, ISI, MTI, and LTI were measured. In patients with ACL tear, age, LT, ML/LT ratio, and QPA measurements were found to be significantly higher. There was no significant difference between the participants' LPTA value and the presence of ACL tear, MM and LM injury. MT and ML/LT ratio were found to be significantly lower in the group with MM tear (p <0.001). The TT-TG distance was found to be significantly lower in the group with LM tear. Increased age, LT, ML/LT ratio, and QPA are predisposed risk for ACL tear. Decreased MT and ML/LT ratio are among the risk factors for MM tear. The anatomical variations are associated with ligament and meniscal injury.

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

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

Concurrent validity and reliability of a semi-automated approach to measuring the magnetic resonance imaging morphology of the knee joint in active youth.

Post-traumatic knee osteoarthritis is attributed to alterations in joint morphology, alignment, and biomechanics triggered by injury. While magnetic resonance (MR) imaging-based measures of joint morphology and alignment are relevant to understanding osteoarthritis risk, time consuming manual data extraction and measurement limit the number of outcomes that can be considered and deter widespread use. This paper describes the development and evaluation of a semi-automated software for measuring tibiofemoral and patellofemoral joint architecture using MR images from youth with and without a previous sport-related knee injury. After prompting users to identify and select key anatomical landmarks, the software can calculate 37 (14 tibiofemoral, 23 patellofemoral) relevant geometric features (morphology and alignment) based on established methods. To assess validity and reliability, 11 common geometric features were calculated from the knee MR images (proton density and proton density fat saturation sequences; 1.5 T) of 76 individuals with a 3-10-year history of youth sport-related knee injury and 76 uninjured controls. Spearman's or Pearson's correlation coefficients (95% CI) and Bland-Altman plots were used to assess the concurrent validity of the semi-automated software (novice rater) versus expert manual measurements, while intra-class correlation coefficients (ICC2,1; 95%CI), standard error of measurement (95%CI), 95% minimal detectable change, and Bland-Altman plots were used to assess the inter-rater reliability of the semi-automated software (novice vs resident radiologist rater). Correlation coefficients ranged between 0.89 (0.84, 0.92; Lateral Trochlear Inclination) and 0.97 (0.96, 0.98; Patellar Tilt Angle). ICC estimates ranged between 0.79 (0.63, 0.88; Lateral Patellar Tilt Angle) and 0.98 (0.95, 0.99; Bisect Offset). Bland-Altman plots did not reveal systematic bias. These measurement properties estimates are equal, if not better than previously reported methods suggesting that this novel semi-automated software is an accurate, reliable, and efficient alternative method for measuring large numbers of geometric features of the tibiofemoral and patellofemoral joints from MR studies.

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

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

Treatment Options for Patellofemoral Arthritis.

To present a synthesis of recent literature regarding the treatment of patellofemoral arthritis RECENT FINDINGS: Risk factors of PFJ OA include patella malalignment or maltracking, injury to supportive structures including the MPFL, dysfunction of hamstring and quadriceps coordination, lower limb alignment, trochlear dysplasia, patellar trauma, or ACL surgery. Special physical exam maneuvers include patellar grind test, apprehension test, and lateral patellar tilt angle. Radiographs that should be obtained first-line include weight bearing bilateral AP, lateral, and Merchant views. CT and MRI are used to assess trochlear dysplasia, excessive patellar height, and TT-TG distance. Non-operative management options discussed include non-pharmacologic treatment (patient education, self-management, physical therapy, weight loss), ESWT, cold therapy, taping, bracing, and orthotics. Pharmacologic management options discussed include NSAIDs, acetaminophen, oral narcotics, and duloxetine. Injection therapies include glucocorticoids, hyaluronic acid, PRP, and other regenerative therapies (BMAC, adipose, or mesenchymal stem cells). Other treatment options include radiofrequency ablation and botulinum toxin. The algorithm for the surgical treatment of PFJ OA can begin with arthroscopic assessment of the PF articular cartilage to address mechanical symptoms and to evaluate/treat lateral soft tissue with or without overhanging lateral osteophytes. If patients fail to have symptomatic improvement, a TTO can be considered in those patients less than 50 years of age or active patients >50 years old. In patients with severe PFJ OA, refractory to the above treatments, PFA should be considered. While early PFA design and technique were less than encouraging, more recent implant design and surgical technique have demonstrated robust results in the literature. Patellofemoral osteoarthritis is a challenging orthopedic problem to treat, in that it can often affect younger patients, with otherwise well-functioning knees. It is a unique entity compared to TF OA with distinct epidemiology, biomechanics and risk factors and treatment options.

The relationship between patellar tilt and quadriceps patellar tendon angle with anatomical variations and pathologies of the knee joint

PurposeTo investigate the association between the knee joint anatomical variations and pathologies, and to describe the quadriceps patellar tendon angle (QPA). MethodsMRIs of 406 cases with a lateral patellar tilt angle (LPT)>5° and a control group of 40 cases with an LPT<5° were retrospectively evaluated. QPA, LPT, trochlear sulcus angle (TSA), tibial tubercle–trochlear groove distance (TT–TG), Insall-Salvati index (ISI), patellar tendon length (PTL), patellar height (PH), lateral trochlear inclination (LTI), trochlear facet asymmetry ratio (TFA) and trochlear depth (TD) were measured. Presence of fat-pad oedema, patellar and trochlear chondromalacia, patellar and quadriceps tendinosis and effusion were evaluated. ResultsThe medians of TSA, PTL, ISI and TT–TG were significantly higher; LTI, TFA and TD were significantly lower in the patient group. The prevalence of SL–Hoffa, non–SL–Hoffa, suprapatellar and prefemoral fat-pad oedema, effusion and chondromalacia were significantly higher in the patient group. LPT was found to be positively correlated with TSA and TT–TG, and negatively correlated with LTI and TD. Cases with trochlear dysplasia, patellar chondromalacia and quadriceps tendinosis had significantly higher LPT. There was a positive correlation between QPA and TSA and a negative correlation between QPA and LTI. Cases with trochlear dysplasia, non–SL–Hoffa oedema, prefemoral fat-pad oedema and quadriceps tendinosis had significantly higher QPA. We found 10°<LPT to be a cut–off value to cause SL–Hoffa fat pad oedema. ConclusionThe anatomical variations of the knee joint are associated with fat-pad, cartilage and tendon pathologies.

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

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. 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). 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. 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.

Relation of the chondromalatia patellae to proximal tibial anatomical parameters, assessed with MRI.

BackgroundMagnetic resonance imaging (MRI) is a non-invasive highly sensitive tool for diagnosing chondromalacia patellae in the early stages. Many studies have evaluated patellar and trochlear morphology with different radiologic indices. We aimed to assess the discriminative power of tibial, patellar, and femoral indices in MRI for chondromalacia patellae.Patients and methods100 cases of chondromalacia, as well as 100 age-matched controls among the patients who underwent knee MRI between February 2017 and March 2019, were included. The standard protocol of knee MRI was applied and the diagnosis of chondromalacia was made on MRI findings. Chondromalacia subjects were also classified as grade 1 to 4 according to the Modified Outerbridge’s MRI grading system. We measured 25 MRI parameters in the knee and adjacent structures to determine the relation between chondromalacia patellae and anatomical MRI parameters.ResultsTibial slope, trochlear depth, lateral trochlear inclination, and lateral patellar tilt angle had significant correlation with chondromalacia. Any increase in lateral trochlear inclination and lateral patellar tilt angle could increase the probability of the disease (Odds ratio [OR] 1.15, 1.13; 95% CI: 1.03–1.30; 1.02–1.26, respectively), while any increase in medial tibial slope and trochlear depth could decrease the probability of chondromalacia (OR 0.85, 0.06; 95% CI: 0.73–0.98, 0.02–0.17, respectively). We also designed a model for the severity of disease by using the patellar height index (relative odds ratio: 75.9).ConclusionsThe result of this study showed the novelty role of tibial anatomy in developing chondromalacia and its mechanism. We also concluded that patellar height might be an important factor in defining disease severity.

Static patellofemoral alignment in anterior cruciate ligament deficient knees; a retrospective analysis with magnetic resonance imaging

Static patellofemoral alignment in anterior cruciate ligament deficient knees; a retrospective analysis with magnetic resonance imaging

Differences in patellofemoral alignment as a result of patellar shape in cruciate-retaining total knee arthroplasty without patellar resurfacing at a minimum three-year follow-up

BackgroundAlthough the patellofemoral (PF) joint shape of the femoral implant in a particular prosthetic design is identical, the articular surface shape of the patella varies between individuals. The present study investigated the effects of patellar shape on the postoperative PF joint in a cruciate-retaining total knee arthroplasty (CR-TKA) without patellar resurfacing and with at least three years of follow-up. MethodsThis study investigated 76 knees of 62 patients who underwent CR-TKA without patellar resurfacing for varus osteoarthritis. Shape of the patella was classified in terms of the patellar facet angle (angle formed by the medial and lateral articular surfaces) as measured on axial plain X-ray. Subjects were divided into Group A with patellar facet angle ≤126° (34 knees) and Group B with patellar facet angle >126° (42 knees). ResultsAnterior knee pain (AKP) was evident in four knees in Group A and one knee in Group B. Postoperative lateral patellar tilt angle was significantly larger in Group A than in Group B. Progression of osteosclerosis in the patella was present in 12 knees in Group A and three knees in Group B. ConclusionThis study found that for a patella with a small patellar facet angle, lateral tilt of the patella was significantly increased after TKA, and a high rate of osteosclerosis was evident at >3years after operation. Performing TKA without patellar resurfacing on a patella with a small patellar facet angle may entail a higher risk of postoperative AKP; pre-operative evaluation of the shape of the patella is therefore important.

The relation between chondromalacia patella and meniscal tear and the sulcus angle/ trochlear depth ratio as a powerful predictor.

To investigate the relation between chondromalacia patella and the sulcus angle/trochlear depth ratio as a marker of trochlear morphology. In addition, we also planned to show the relationship between meniscus damage, subcutaneous adipose tissue thickness as a marker of obesity, patellar tilt angle and chondromalacia patella. Patients with trauma, rheumatologic disease, a history of knee surgery and patellar variations such as patella alba and patella baja were excluded. Magnetic resonance images of the knees of 200 patients were evaluated. Trochlear morphology from standardized levels, patellar tilt angle, lateral/medial facet ratio, subcutaneous adipose tissue thickness from 3 locations and meniscus injury were assessed by two specialist radiologists. Retropatellar cartilage was normal in 108 patients (54%) at radiological evaluation, while chondromalacia patella was determined in 92 (46%) cases. Trochlear sulcus angle and prepatellar subcutaneous adipose tissue thickness were significantly high in patients with chondromalacia patella, while trochlear depth and lateral patellar tilt angle were low. The trochlear sulcus angle/trochlear depth ratio was also high in chondromalacia patella and was identified as an independent risk factor at regression analysis. Additionally, medial meniscal tear was observed in 35 patients (38%) in the chondromalacia patella group and in 27 patients (25%) in the normal group, the difference being statistically significant (P = 0.033). An increased trochlear sulcus angle/trochlear depth ratio is a significant predictor of chondromalacia patella. Medial meniscus injury is more prevalent in patients with chondromalacia patella in association with impairment in knee biomechanics and the degenerative process.

Should the position of the patellar component replicate the vertical median ridge of the native patella?

BackgroundIn total knee arthroplasty (TKA), the position of the patellar component can affect patellar tracking. However, the patellar component cannot always replicate the original high point of the patella because of anatomical variance. This study investigated whether altering the highest point of the patella can affect outcomes of primary TKA, especially in patients having a patella with a far-medialized median ridge. MethodsA retrospective review was performed for 177 knees (143 patients) treated with primary TKA between July 2011 and March 2014. Group 1 (34 knees) had the patellar component displaced over three millimeters from the median ridge, while Group 2 (143 knees) had the patellar component placed on the original median ridge position. The one-year follow-up outcomes were reviewed, including: patellar tilt angle, Knee Society Score, Feller Patellar Score, and modified Kujala Anterior Knee Pain Score. ResultsMean (±standard deviation) displacement of the patellar component in Group 1 was 3.97±0.97mm lateral to the original position of the median ridge, with a significant decrease in lateral patellar tilt angle (P<0.001). Lateral patellar tilt showed a positive correlation with the medialization of the patellar component (P<0.001, r=0.401). Ability to rise from a chair was better in Group 1 (P=0.025). There were no other between-group differences in other clinical outcomes. ConclusionsThere should be no need for the patellar component to replicate the original highest point of the native patella in primary TKA.

Bone and joint modeling from 3D knee MRI: feasibility and comparison with radiographs and 2D MRI

PurposeThe purpose was to evaluate feasibility of bone and joint segmentations from three-dimensional magnetic resonance imaging (3D MRI). MethodsSegmented joint models from 3D MRI data set were obtained for 42 patients. Blinded angular and joint space measurements were performed on 3D MRI model, two-dimensional (2D) MRI, and radiography (XR). ResultsMedial joint space was similar on both XR and 3D MRI (P=.3). The XR measurements were statistically different but closer to 3D MRI for lateral patellar tilt angle, patellar tendon length, and lateral knee joint space, whereas 2D MRI measurements were closer to XR in terms of trochlear depth, sulcal angle, and patellar length. Conclusion3D bone and joint segmentations are feasible from isotropic MRI data sets.

Double bundle medial patello-femoral ligament reconstruction for recurrent patellar dislocation – A modified technique and documentation of importance of arthroscopy

AimEvaluation of outcome of double bundle MPFL reconstruction for recurrent patellar dislocation using semitendinosus tendon autograft passed through vertical tunnel in patella and to document the scope of arthroscopic assistance during the procedure. MethodsThe prospective case series study included 22 patients (17 females and 5 males) with recurrent lateral patellar dislocation. The average age was 29 years (15–55 years) and all underwent arthroscopy-assisted MPFL reconstruction using semitendinosus tendon autograft passed through vertical tunnel in patella. ResultsAt an average follow-up of 30 months (17–43 months), none had apprehension or re-dislocation of patella postoperatively. Intraoperative arthroscopy was useful in the confirmation of patella tracking; removal of loose body (9 cases), performing chondroplasty (11 cases), simultaneous management of associated intra-articular pathology (4 cases) and careful tunnel placement for tendon graft. Radiologically, the congruence angle improved from pre-operative average of 13.41° (−9° to +53°) to 2.59° (−10° to +14°) and the lateral patellar tilt angle improved from 11.95° (2° to 21°) to 4.18° (0° to 9°) post-operatively. Functionally, the Kujala score improved from pre-operative average of 49.59 (42–76) to 92.18 (86–96), the Lysholm score from 62.13 (56–70) to 94.31 (90–100) and the Tegner activity scale from 2.31 (2–3) to 3.31 (3–4) post-operatively. ConclusionDouble bundle MPFL reconstruction for recurrent patellar dislocation using looped semitendinosus tendon autograft passed through vertical tunnel in patella produces promising radiological and functional results. The study highlights the value of arthroscopic assistance during the procedure to improve the outcome.

Femoropatellar radiographic alterations in cases of anterior cruciate ligament failure

ObjectiveTo make a comparative analysis on three femoropatellar radiographic parameters, between knees with chronic failure of the anterior cruciate ligament (ACL) and normal knees. MethodsThirty volunteer patients with a diagnosis of unilateral isolated chronic ACL injury for more than one year and a normal contralateral knee were selected. Digital radiographs were produced for all the patients, on both knees in absolute lateral view at 30° of flexion, with and without load-bearing on one leg, and in axial view of the patella at 30°. The Caton–Deschamps patellar height index, Merchant patellar congruence angle and Laurin lateral patellar tilt angle were measured on the radiographs obtained from the normal knees and knees with ACL injuries, and comparative analysis was performed between these two groups. ResultsThe patellar height was statistically significantly lower (p<0.001) in the knees with ACL failure than in the normal knees, both on radiographs without loading and on those with single-foot loading. The Merchant patellar congruence angle was significantly smaller (p<0.001) in the normal knees and the lateral patellar tilt angle was smaller (p<0.001) in the knees with ACL failure. ConclusionChronic ACL failure gave rise to a statistically significant change in the femoropatellar radiographic values studied (p<0.001). Knees with injuries to this ligament presented lower patellar height values, greater tilt and lateral displacement of the patella, in relation to the femoral trochlea, in comparison with the normal contralateral knees.