Patellar Malalignment Research Articles

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.

Anterior Knee Pain (AKP) and its Relationship to Quadriceps Angle and Anthropometric Parameters: A Hospital-Based Cross-Sectional Study from Iraq

Abstract Background: Anterior knee pain (AKP) is a common condition, especially among physically active adults who present a clinical challenge. Patellar malalignment is thought to be an important cause. Measuring quadriceps (Q) angle significant test used in the assessment of patellar alignment and hence used in the assessment of AKP. Objectives: To assess the relationship between AKP and Q angle among ample Iraqi patients. Materials and Methods: The right and left Q angles of 100 participants were measured using a universal goniometer. The participants were divided into three groups: controls, patients with left AKP (LAKP), and patients with right AKP (RAKP). The relationship between Q angles and different groups was tested using appropriate statistical tests. Results: The left Q angles for males measure 14.1 ± 1.9 in controls, 17.7 ± 1.6 in LAKP cases and 16.1 ± 1.8 in RAKP cases, and for the females 16.1 ± 1.8 in controls, 18.1 ± 1.8 in LAKP cases and 17.1 ± 2.5 in RAKP cases. The right Q angles for males measure 15.6 ± 2.2 in controls, 15.1 ± 2.7 in LAKP cases and 19 ± 1.6 in RAKP cases, and for the females were 17.7 ± 2.4 in controls, 17.9 ± 2.2 in LAKP cases and 19.9 ± 2 in RAKP cases. Both Q angles (right and left) were greater in females than in males and both were greater in cases than in controls. Conclusion: The study concluded that there is a significant association between AKP and quadriceps femoris angle measurement in both genders. Therefore, clinical and/or radiological demonstration of quadriceps angle can be used as a means for initial detection of AKP.

Incidence of Complications After Tibial Tubercle Osteotomy and Tibial Tubercle Osteotomy With Distalization

Background: Tibial tubercle osteotomy (TTO) is a well-established surgical treatment option for patellofemoral instability and pain. TTO with distalization (TTO-D) is indicated for patients with patellofemoral instability, patellar malalignment, and patella alta. The current literature demonstrates several complications that may be associated with TTO, with reportedly higher rates of complications associated with TTO-D. Purpose: To analyze and compare complication rates after TTO without distalization (TTO-ND) and TTO-D and assess risk factors associated with complications. Study Design: Cohort study; Level of evidence, 3. Methods: All skeletally mature patients who underwent TTO with or without distalization by a single surgeon between September 2014 and May 2023 with a minimum of 6 months of clinical follow-up were retrospectively reviewed. Patient factors, surgical indications, perioperative data, and complications were collected via a retrospective review of electronic medical records. Concomitant procedures were categorized as intra-articular, extra-articular, and osteotomies. Results: A total of 251 TTOs (117 TTO-D, 134 TTO-ND) were included in the study group. Postoperative complications were observed in 15 operations (6%), with arthrofibrosis as the most common complication (10 operations [4%]). TTO-D and TTO-ND had similar rates of complication (5% vs 7%; P = .793). Clinical nonunion was observed in 3 operations (3%) in the TTO-D cohort and 1 operation (1%) in the TTO-ND cohort. In the TTO-D cohort, concomitant intra-articular procedures were significantly associated with an increased likelihood of complications in a univariate model. In the TTO-ND cohort, an increased tourniquet time was significantly associated with an increased likelihood of complications in a univariate model. For all TTOs as well as the TTO-D and TTO-ND cohorts, there were no significant associations between patient or surgical variables in a multivariate model. Conclusion: TTO with and without distalization is a safe procedure with low rates of complication. TTO-D was not associated with a higher rate of complications compared with TTO-ND. There was no association between complications and surgical variables for TTO procedures.

Cartilage Restoration of the Patellofemoral Joint: Techniques and Outcomes

Patellofemoral cartilage injuries present a complex challenge due to the unique anatomy and biomechanics of the joint. The daily activities involving the knee, such as weight-bearing, stair ambulation, and squatting, impose high loads on the joint, increasing the risk of cartilage overload and subsequent cartilage injury. Additionally, several anatomical abnormalities, including patellar malalignment, patella alta, and trochlear dysplasia, can influence the behavior of the patellofemoral joint, leading to instability and further elevating the risk of cartilage injuries. Surgical management of patellofemoral cartilage injuries remains a topic of modern debate. The effectiveness and suitability of different techniques depend on individual indications and the characteristics of the cartilage defect. This chapter explores the use of cartilage repair and restoration techniques for patellofemoral cartilage defects. Here, we discuss aspects of the surgical techniques, their outcomes, and provide insights into when staging arthroscopy or concomitant stability surgery should be considered.

Resurfacing Versus Non-resurfacing Patella in Total Knee Replacement: When and What to Choose.

The opinion on the necessity of patella resurfacing has been deeply divided in the scientific community. There are three approaches to the management of the patella in total knee arthroplasty (TKA). The first method involves always resurfacing the patella, the second method involves never resurfacing it, and the third method involves resurfacing the patella only under specific circumstances. Different data support each of these strategies, but no consensus on the best management has been reached. This is a retrospective study of 106 cases of TKA (including 29 resurfaced patellas and 77 non-resurfaced patellas), over 5 years, at the Trauma-Orthopedics Department of theCheikh Khalifa International University Hospital, Mohammed VI University of Health Sciences, Casablanca, Morocco. Our objective is to conduct a comparative study between TKA with patella resurfacing and those without resurfacing, by analyzing the functional and radiological results obtained after the operation, to show each technique's advantages and disadvantages. The average age of our patients was 65 years with extremes ranging from 46 to 80 years. There was a clear female predominance with a sex ratio of 0.2. The left side was predominantly affected. Primary gonarthrosis was the main diagnosis. Our results showed no significant difference between the two groups in terms of patient satisfaction and Knee Society Score (KSS). Nevertheless, complications generated by resurfacing, such as infection, anterior pain, stiffness, and loosening of the patellar component, as well as additional costs and increased operative time, were observed. In the majority of meta-analyses, there was no discernible difference in clinical and functional results between the resurfaced and non-resurfaced groups, suggesting that patellar resurfacing is not beneficial and, therefore, unnecessary. It appears that regular resurfacing is not necessary. However, there is agreement that resurfacing the patella is the best course of action for patients with inflammatory arthropathy, considerable patella malalignment, and severe patellofemoral osteoarthritis. There are arguments in favor of each of the patella resurfacing techniques, but none of them are particularly compelling, each of these strategies has itsadvantages and should not be considered bad. The final decision, therefore, rests on each surgeon's practice, training, and experience.

Patellar malalignment correlates with increased pain and increased synovial stress hormone levels-A cross-sectional study.

Risk factors for the development of pain in the context of knee osteoarthritis (KOA) remain unclear. Radiological findings often do not correlate with clinical findings, so other pathomechanisms in the development and perception of pain must play a role. The purpose of this study is to investigate the correlation of increased sympathetic nervous system (SNS) activity (measured by subjective and objective chronic stress parameters) with KOA severity, patellofemoral malalignment, and pain. 47 patients with KOA were assessed. Radiological measurements of tibiofemoral and patellofemoral parameters (Kellgren-Lawrence-score, patellar tilt (PT), Caton-Deschamps-Index and Hepp´s classification) were performed and correlated with knee-specific questionnaires (WOMAC®, KSS©) and chronic stress questionnaires (PSQ-20). Additionally, parameters associated with chronic stress were quantified in synovial fluid and serum samples from patients. PT correlated significantly with Caton-Deschamps-Index (r = 0.394,p = 0.006) and with medial patellofemoral joint space (r = 0.516,p<0.001). In addition, asymmetric trochlear groove (Hepp's classification > II) was associated with significantly higher PT values (p = 0.014). A negative correlation between PT and KSS©-symptoms subgroup was found (r = -0.340,p = 0.024). Patients with PT<5° had significantly higher scores in the Knee Society Score©-symptoms subgroup (p = 0.038). A positive and significant correlation between synovial aldosterone levels and PT was observed (r = 0.548,p = 0.042). The results of this study indicate that patellar malalignment might correlate with increased pain. The previous specification of standard PT values must be reconsidered as even low PT values seem to play a role in the occurrence of patellofemoral osteoarthritis symptoms. Lower PT values might lead to aggravated symptoms in patients with KOA due to a narrow medial patellofemoral joint space. In addition, PT might induce the release of synovial stress biomarkers and thus contribute to the progression of KOA.

Patellar Tracking: An Old Problem with New Insights.

Patellofemoral pain and instability are common indications for imaging that are encountered in everyday practice. The authors comprehensively review key aspects of patellofemoral instability pertinent to radiologists that can be seen before the onset of osteoarthritis, highlighting the anatomy, clinical evaluation, diagnostic imaging, and treatment. Regarding the anatomy, the medial patellofemoral ligament (MPFL) is the primary static soft-tissue restraint to lateral patellar displacement and is commonly reconstructed surgically in patients with MPFL dysfunction and patellar instability. Osteoarticular abnormalities that predispose individuals to patellar instability include patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Clinically, patients with patellar instability may be divided into two broad groups with imaging findings that sometimes overlap: patients with a history of overt patellar instability after a traumatic event (eg, dislocation, subluxation) and patients without such a history. In terms of imaging, radiography is generally the initial examination of choice, and MRI is the most common cross-sectional examination performed preoperatively. For all imaging techniques, there has been a proliferation of published radiologic measurement methods. The authors summarize the most common validated measurements for patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Given that static imaging is inherently limited in the evaluation of patellar motion, dynamic imaging with US, CT, or MRI may be requested by some surgeons. The primary treatment strategy for patellofemoral pain is conservative. Surgical treatment options include MPFL reconstruction with or without osseous corrections such as trochleoplasty and tibial tubercle osteotomy. Postoperative complications evaluated at imaging include patellar fracture, graft failure, graft malposition, and medial patellar subluxation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Inlay, Onlay, Oval, or Round, Patellar Implant Choice Outcomes Do Not Confound: Commentary on an article by Monther A. Gharaibeh, MBBS, FJMA, et al.: "Does Choice of Patellar Implant in Total Knee Arthroplasty Matter? A Randomized Comparative Trial of 3 Commonly Used Designs".

Commentary Although the prevalence of total knee arthroplasty (TKA) continues to grow, the overall outcomes remain good but still exhibit a subgroup of patients who are not entirely satisfied with their result1. Substantial difficulties in evaluating the differences between satisfied and unsatisfied patients are enhanced by the many choices and alternatives available to knee arthroplasty surgeons. A few notable examples include approach (medial parapatellar compared with other approaches), fixation (cemented, hybrid, or uncemented), posterior cruciate ligament status (cruciate-sacrificing compared with cruciate-sparing), and alignment (kinematic compared with mechanical). Included in the long list of alternatives is the choice of patellar implant type used by the surgeon. Many of us have either attended or participated in professional meetings or symposia in which faculty present their biased rationale for supporting their choice of patellar implant (or not resurfacing). Unfortunately, a paucity of strong evidence usually accompanies these conceivably strongly worded recommendations. Gharaibeh et al. should be congratulated for designing and completing a well-done prospective randomized trial assessing the differences between 3 patellar choices: inlay (IN), onlay round (OR), and onlay oval (OO), or anatomic. Historically, patellar instability and pain were common causes of revision TKA. Although infection has overtaken patellar sources of revision, patellar instability and pain remain among the top reasons for revision2. The percentage of unsatisfied patients who underwent TKA secondary to patellar causes is unknown, but patients who undergo revision TKA secondary to patellar sources of pain and instability are a defined subset of those patients undergoing revision TKA. Evidence-based recommendations with regard to patellar implant choices in TKA have been wanting, and Gharaibeh et al. designed a thoughtful and simple prospective trial to answer the question. Thankfully, the investigators randomized consecutive patients to the trial and measured both clinical and patient-reported outcomes. The Kujala score is likely not recognized by U.S. surgeons, but it is a validated method of assessing patellar pain, including in knee arthroplasty. The authors also included a robust set of radiographic measures, and these would have been strengthened by preoperative measurements as well. Their data would have been bolstered by preoperative alignment indices, as postoperative patellar malalignment and tracking can be attributed to overcorrection or undercorrection of underlying abnormalities. The authors also recorded whether a later facetectomy was performed during the procedure. They reported these findings based on their concern for lateral patellar bone compression syndrome. Not surprisingly, they found that a lateral facetectomy was required less frequently with the OO design patellar implants than the OR design patellar implants. Gharaibeh et al. correlated this finding with improved vascularity of the patella in the single photon emission computed tomography (SPECT) Delayed 4 subset, but differences were not noted otherwise in the vascularity analysis. Although the findings are used to imply that the OO-design patellar implants may improve outcomes, this study was not necessarily powered to assess that over time. With regard to outcomes, the authors showed that, although differences in radiographic indices between implant types did achieve significance for the Caton-Deschamps index, the overall indices for all implants were acceptable. Although the overall radiographic indices skewed slightly in favor of the OO design, these differences did not result in improved patient-reported outcomes. The Kujala scores for all implant types showed improvement and no difference between types, and the Knee injury and Osteoarthritis Outcome Score (KOOS) showed minimal and likely clinically unimportant differences between implant types. In conclusion, this is the type of study that helps to advance the science of knee arthroplasty. Although some will take the minimal radiographic differences as evidence that the OO design is superior, the clinical findings, including a patellar-specific outcome, do not support that observation. As we struggle to identify, predict, and address the factors that contribute to unsatisfactory outcomes in knee arthroplasty, this study helps to eliminate patellar implant design as a factor in those poor outcomes.

Improvement of Pain and Function by Using Botulinum Toxin Type A Injection in Patients with an Osteoarthritic Knee with Patellar Malalignment: An Electromyographic Study.

Objective: To determine the pain and electromyographic (EMG) amplitude ratio of the vastus medialis oblique (VMO) to the vastus lateralis (VL) after botulinum toxin type A (BTA) was injected in the bilateral osteoarthritic knee of patients with patellar malalignment for analysis. Material and methods: A total of fifteen patients were recruited; the more symptomatic knee of each patient received a BTA injection (BTA side). The other set of patients were left untreated. In all, fifteen healthy participants comprised the control group. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and numeric rating scale (NRS) for pain were assessed. The EMG amplitude of VL and VMO activity was recorded using an isokinetic dynamometer and synchronized using the BIOPAC MP100. The data were collected before and at 4, 8, and 12 weeks post−BTA injection. Results: The EMG ratios of the patient group were lower than those of the control group at all testing velocities (p < 0.05). The VMO/VL ratio improved significantly on the BTA side only. The VMO/VL ratios on the BTA side were higher than those on the untreated side (p < 0.05). Knee pain decreased significantly after the BTA injection. The EMG ratios were negatively correlated with the NRS and WOMAC scores. Conclusion: BTA injection effectively reduces knee pain and restores the EMG ratio between the VMO and VL.

Lateral retinacular release in concordance with medial patellofemoral ligament reconstruction in patients with recurrent patellar instability: A computational model

BackgroundThe aim of this study was to develop and validate a finite element (FE) model of the patellofemoral joint to analyze the biomechanics of lateral retinacular release after medial patellofemoral ligament (MPFL) reconstruction in patellar malalignment (increased tibial tubercle–trochlear groove distance (TT-TG)). We hypothesized that lateral retinacular release is not appropriate in patellar instability addressed by MPFL reconstruction due to decreased lateral stability and inappropriate adjustment in patellofemoral contact pressures. MethodsA FE in-silico model of the patellofemoral joint was developed and validated. The model was used analyze the effect of lateral retinacular release in association with MPFL reconstruction on patellofemoral contact pressures, contact area, and lateral patellar displacement during knee flexion. ResultsMPFL reconstruction alone results in restoration of patellofemoral contact pressures throughout the entire range of motion (0–90°), mimicking the results from healthy condition. The addition of the lateral retinacular release to the MPFL reconstruction resulted in significant reductions in both patellofemoral contact pressure and contact area. Lateral retinacular release resulted in more lateral patellar displacement during the mid-flexion knee range of motion. ConclusionsCombination of lateral retinacular release with MPFL reconstruction in patients with increased TT-TG is not recommended as MPFL reconstruction alone for first-line management of recurrent patellar instability offers a greater biomechanical advantage and restoration of contact forces to resemble that of the healthy knee. The presented biomechanical data outlines the effect of concomitant MPFL reconstruction and lateral retinacular release to help guide surgical planning for patients with recurrent patellar instability due to malalignment.

Combined distal femoral osteotomy and tibial tuberosity distalization is effective in patients presenting with patellar instability and patellofemoral pain due to patella alta and femoral malalignment.

Patellar malalignment has been considered one of the major pathomechanical causes of patellofemoral instability and pain. The results have been reported after femoral varization/torsional osteotomy and tibial tuberosity distalization osteotomy (TTD-O). However, the combination of a femoral deformity (genu valgum/increased femur antetorsion) and patella alta remains underreported. Therefore, the aim of this study was to investigate the clinical outcomes of patients simultaneously treated by distal femoral osteotomy and TTD-O. The hypothesis was that restoration of patellofemoral (PF) alignment via the abovementioned osteotomies would achieve good patient-reported outcome measures. Between 2016 and 2019, a series of 25 knees in 20 patients were treated by a distal femoral osteotomy combined with a TTD-O aiming to correct patellofemoral malalignment consisting of genu valgum and/or increased femur antetorsion and patella alta. Six patients were lost to follow-up, and one patient refused to participate. Thus, 17 knees in 13 patients (male/female 1/12; age 27.4 ± 5.4years) were included and comprised the study group for this investigation. Patients were evaluated after a mean of 3.1 ± 0.9years postoperatively. The Kujala anterior knee pain scale and the PF-subscale of the Knee Osteoarthritis and Outcome score (KOOS-PF) were used to assess patients' reported outcome measures from pre- to postoperatively. The mean amount of torsional correction, valgus correction, and tibial tuberosity distalization averaged 14° (10°-18°), 5.2° (3.8°-8°), and 9mm (6°-15mm), respectively. The Kujala score increased by an average of 24.18 points from a mean of 66.6 ± 18.3 points (34-93 points) preoperatively to 90.8 ± 14.2 points (44-100 points) postoperatively (95% CI -33.0 to -15.3; p < 0.0001). The KOOS-PF score increased by an average of 33.7 points from a mean of 49.5 ± 24.5 points (9.1-88.6 points) preoperatively to 83.2 ± 21.6 points (15.9 -100 points) postoperatively (95% CI -47.5 to -19.9; p < 0.0001). The findings of this study indicate that the combination of a distal femoral osteotomy and a tibial tuberosity distalization osteotomy is effective in patients presenting with patellar instability and patellofemoral pain due to patella alta and femoral malalignment.

Combined MPFL reconstruction and tibial tuberosity transfer avoid focal patella overload in the setting of elevated TT-TG distances.

Objectives are (1) to evaluate the biomechanical effect of isolated medial patellofemoral ligament (MPFL) reconstruction in the setting of increased tibial tuberosity-trochlear groove distance (TTTG), in terms of patella contact pressures, contact area and lateral displacement; (2) to describe the threshold of TTTG up to which MPFL reconstruction should be performed alone or in combination with tibial tuberosity transfer. A finite element model of the knee was developed and validated. The model was modified to simulate isolated MPFL reconstruction, tibial tuberosity transfer and MPFL reconstruction combined with tibial tuberosity transfer for patella malalignment. Two TT-TG distances (17mm and 22mm) were simulated. Patella contact pressure, contact area and lateral displacement were analysed. Isolated MPFL reconstruction, at early degrees of flexion, restored normal patella contact pressure when TTTG was 17mm, but not when TTTG was 22mm. After 60° of flexion, the TTTG distance was the main factor influencing contact pressure. Isolated MPFL reconstruction for both TTTG 17mm and 22mm showed higher contact area and lower lateral displacement than normal throughout knee flexion. Tibial tuberosity transfer, at early degrees of flexion, reduced the contact pressure, but did not restore the normal contact pressure. After 60° of flexion, the TTTG distance was the main factor influencing contact pressure. Tibial tuberosity transfer maintained lower contact area than normal throughout knee flexion. The lateral displacement was higher than normal between 0° and 30° of flexion (< 0.5mm). MPFL reconstruction combined with tibial tuberosity transfer produced the same contact mechanics and kinematics of the normal condition. This study highlights the importance of considering to correct alignment in lateral tracking patella to avoid focal patella overload. Our results showed that isolated MPFL reconstruction corrects patella kinematics regardless of TTTG distance. However, isolated MPFL reconstruction would not restore normal patella contact pressure when TTTG is 22mm. For TTTG 22mm, the combined procedure of MPFL reconstruction and tibial tuberosity transfer provided an adequate patellofemoral contact mechanics and kinematics, restoring normal biomechanics. This data supports the use of MPFL reconstruction when the patient has normal alignment and the use of combined MPFL reconstruction and tibial tuberosity transfer in patients with elevated TT-TG distances to avoid focal overload.

Association of patella alignment with cartilage relaxation times and self-reported symptoms in individuals with patellofemoral degeneration.

To determine the cross-sectional and longitudinal associations of patella alignment with cartilage relaxation and patients' self-reported symptoms. Thirty participants with isolated patellofemoral joint (PFJ) degeneration (six males, 53.7 ± 9.3 years) and 24 controls (12 males, 47.6 ± 10.7 years) were included. Magnetic resonance assessment was performed to provide grading of structural abnormalities, cartilage relaxation times, and patella alignment. Self-reported symptoms were assessed using the self-administrated knee injury and osteoarthritis outcome score (KOOS). All participants were examined at baseline and 3 years. Statistical parametric mapping and Pearson partial correlation were used to evaluate the associations between patella alignment with cartilage relaxation times and self-reported symptoms, respectively. The analyses were performed between baseline (cross-sectional) as well as the baseline against 3 years (longitudinal). Results indicated that patella height and patella flexion were associated with T1ρ and T2 relaxation times at baseline (percentages of voxels showing significant correlation [PSV] = 10.1%-24.8%; mean correlations [R] = 0.34-0.36; mean p = 0.015-0.026). Furthermore, greater patella lateral alignment, lateral tilt, and lateral spin were associated with longer T2 times at 3 years (PSV = 11.0%-14.4%, R = 0.39-0.44, p = 0.017-0.028). Last, a higher patella was associated with a lower KOOS at baseline and at 3 years (R = -0.33 to -0.35). The study suggests that patella malalignment is a risk factor for worsening cartilage health, informing clinicians of a better rehabilitation program that targets PFJ degeneration.

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.

Measurements of Patellofemoral Morphology Characteristics in Indonesian Population: an MRI Based Study

Patellar malalignment is the imbalance relationship between patella and trochlea, in which clinical findings most of the time are obscured; hence diagnosis is often challenging. Magnetic resonance imaging (MRI) is the most sensitive tool to detect subtle patellar malalignment features, so diagnosis can be made early. However, there has been no clear consensus on the normal value of patella morphology until today. This study aims to determine patellofemoral morphology values in Indonesian using MRI. This was a retrospective study of 202 patients aged 18-40 years old with knee problems without patellar instability. Patellar morphology parameters including Insal Savati ratio (IS ratio), patellar tilt angle (PTA), sulcus angle (SA) and tibial tubercle-trochlear groove distance (TT-TG) were evaluated and recorded for statistical analysis. There was no significant correlation between anthropometric values and patellar morphology values. There were significantly higher PTA, SA and TT-TG values in females compared to males. The mean value of the IS ratio in the Asian population using MRI was 0.99 ± 0.14, PTA was 9.09 ± 6.88, SA was 139.20 ± 6.38, and TT-TG distance was 8.00 ± 5.25. Further studies with larger samples and multi-center results are required.

Longitudinal Changes of Patellar Alignment Before and After Anterior Cruciate Ligament Reconstruction With Hamstring Autograft

Background: Evidence has suggested that after anterior cruciate ligament (ACL) reconstruction (ACLR), individuals exhibit patellar malalignment; however, it is unknown if patellar alignment changes over time. Purpose: To examine the longitudinal changes in patellar alignment before, 6 months after, and 3 years after ACLR and to compare these variations, if present, with patellar alignment in controls. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 35 patients who had ACLR using hamstring autograft (19 male; age, 29.9 ± 7.7 years; body mass index, 23.8 ± 2.5) and 20 controls (13 male; age, 30.4 ± 4.8 years; body mass index, 24.3 ± 2.7) participated. All patients underwent bilateral knee magnetic resonance imaging with the knee in extension and 30° of flexion using sagittal T2-weighted, fat-saturated fast spin-echo images to assess patellar alignment in 6 degrees of freedom: anterior-posterior, medial-lateral, and superior-inferior translations; flexion; tilt; and spin. Patients who had ACLR were assessed before (ACL-deficient state) and 6 months and 3 years after ACLR, while control participants were only assessed once. One-way repeated-measures analysis of variance was used to examine patellar alignment across time in the ACLR group. If changes were present, the independent t test was carried out to examine the differences between ACLR knees and control knees. Results: In the knee-extended condition, greater patellar lateral displacement was observed at the ACL-deficient state and 6 months after ACLR compared with 3 years after ACLR within the ACLR group (P < .001 and P = .043, respectively) and compared with the control group (P = .001 and P = .039, respectively). Greater patellar lateral tilt was observed at the ACL-deficient state compared with 3 years after ACLR (P = .003) and compared with the control group (P = .018). In the knee-flexed condition, greater anterior displacement was observed at the ACL-deficient state compared with 3 years after ACLR (P = .001) and compared with the control group (P = .011), and it was also observed at 6 months after ACLR compared with the control group (P = .019). Less lateral spin was observed at the ACL-deficient state (P = .042) and 6 months after ACLR (P = .004) compared with 3 years after ACLR and compared with the control group (P = .004 for both). No patellar alignment measures in the ACLR knees at 3 years were significantly different from those of the controls. Conclusion: Patellar malalignment in individuals before and after ACLR subjected to longitudinal changes, and the differences in alignment between ACLR and controls diminished over 3 years.

Prone-positioned knee arthroscopy for isolated retropatellar cartilage defects with gel-type autologous chondrocyte implantation.

Treatment of isolated retropatellar cartilage defects using current gel-type regenerative methods requires settlement of the gel to the underlying subchondral bone under gravity; thus, prone positioned arthroscopy is used. Isolated retropatellar contained cartilage defect size >2.5 cm2. Age <40years, epiphyseal closure, cartilage defect grade3/4 (International Cartilage Repair Society). Cartilage defects at medial or lateral femorotibial compartments, at the trochlea, with degenerative genesis, rheumatoid arthritis, local infection, patellar malalignment, patellofemoral dysplasia, knee instability, knee malalignment >3°, kissing lesions. Two-stage procedure: At initial arthroscopy, chondrocytes were harvested. At the second stage, the patient was positioned prone and the leg with athigh tourniquet was fixed in aleg holder. Removal of table extension below the knee and support of foot in sling to prevent knee hyperextension. Placement of 2lateral portals. Lesion visualized and debrided, followed by aspiration of intra-articular fluid. Aloop, placed posterior to the patellar ligament using alasso, was used to suspend aweight to expand the patellofemoral space. The lesion was then dried using asponge. NOVOCART® Inject (TETEC, Reutlingen, Germany) administered onto the defect. Gel was allowed to solidify for15 min and operation was completed. Knee locked in extension using abrace for 6weeks. Continuous passive motion applied and incrementally increased until full range of motion (ROM) at week6. Weight-bearing as tolerated was allowed with the knee in extension. Routine clinical follow-up after 3, 6 and 12months. Mean age of the 5patients was 23 ± 6 (range 14-30) years; mean follow-up time after surgery 28 ± 7 (range 20-40) months. All patients returned to full activity without residual knee ROM restriction. Clinical examination at the latest follow-up revealed aKujala score of 90 ± 12 points and Lysholm score of 95 ± 5 points. MRI showed filled cartilage defects in all patients. Mocart score was 63 ± 7 points. Cartilage was inhomogeneous and hyperintense at the repaired site. Quantitative measurement of the patella mobility of the operated knee under atranslating force of 10 N showed medial and lateral displacements of 21 ± 5 and 15 ± 2 mm and on the healthy side 22 ± 5 and 19 ± 3 mm, respectively.

Evaluation of the Insall-Salvati Ratio Among the Vietnamese Population: Application for Diagnosis of Patellar Malalignment.

Introduction and PurposeAn abnormal patellar position has been proven to be associated with anterior knee pain and several other conditions that affect the patellofemoral joint. The purpose of this study was to determine the incidence of patella alta and patella baja and the applicability of the normal range of the Insall-Salvati ratio in the Vietnamese population.MethodologyMagnetic resonance imaging (MRI) was used to examine 455 Vietnamese subjects’ knees. The Insall-Salvati ratio—the ratio of patellar ligament length (LL) and patellar length (PL)—was measured using sagittal T1-weighted images.ResultsThe overall mean LL/PL ratio was 1.02 (standard deviation 0.15). No significant differences in the LL/PL ratio were observed between sexes. The frequencies of patella alta (Insall-Salvati ratio >1.32) and patella baja (Insall-Salvati ratio <0.72) were 0.9% and 2.4%, respectively.ConclusionThe Insall-Salvati ratio is applicable to Vietnamese populations in which high flexion activities such as kneeling and sitting cross-legged are customary. According to our measurement, the normal range of the ratio among Vietnamese subjects was 0.72 to 1.32.

Intraoperative patellar maltracking and postoperative radiographic patellar malalignment were more frequent in cases of complete medial collateral ligament release in cruciate-retaining total knee arthroplasty

BackgroundPatellar maltracking after total knee arthroplasty (TKA) can lead to significant patellofemoral complications such as anterior knee pain, increased component wear, and a higher risk of component loosening, patellar fracture, and instability. This study was to investigate the preoperative and operative variables that significantly affect patellar tracking after cruciate-retaining TKA.MethodsWe studied 142 knee joints in patients who had undergone TKA: the knees were dichotomized based on postoperative patellar tracking, which was evaluated on patellar skyline, axial-projection radiographs: group 1, normal patellar tracking (lateral tilt ≤ 10° and displacement ≤ 3 mm) and group 2, patellar maltracking (lateral tilt > 10° or displacement > 3 mm). The patients’ demographic data and clinical and radiographic measurements obtained before and after surgery were compared between the two groups.ResultsPreoperative lateral patellar displacement was greater (4.1 ± 2.6 mm vs. 6.0 ± 3.5 mm), as was the frequency of medial collateral ligament (MCL) release (3/67 vs. 24/75) in group 2 than in group 1 (p < 0.001 and p < 0.001, respectively). The distal femur was cut in a greater degree of valgus in group 1 than in group 2. (6.3 ± 0.8° vs. 6.0 ± 0.8°) (p = 0.034).ConclusionsComplete release of the MCL during surgery was associated with patellar maltracking (logistic regression: p = 0.005, odds ratio = 20.592). Surgeons should attend to patellar tracking during surgery in medially tight knees.Level of evidenceRetrospective comparative study, level III.

Patellofemoral Chondropathy Areas in Folk Dancers: An MRI Study.

Patellofemoral chondropathy (PFC) is one of the most important causes of patellofemoral pain syndrome. PFC may occur as a result of anatomic reasons such as patellar malalignment and/or increased patellofemoral joint stresses. Most research on this subject has involved sports injuries and anatomic variations. The literature is scarce on PFC related to the dance. Fourteen dancers (14 knees, all male) were found to have PFC based on MRI evaluations and clinical examinations between January 2010 and December 2019 (3 dancers were excluded due to prior surgeries of the knee). Age, sex, side of injury, range of motion, Q angle, types of dances, body mass index, and patellar specifics (alta, baja, Wiberg) were recorded for 11 dancers included in the study. We observed PFC at the femoral contact areas (FCA) and patellar contact areas (PCA) of Goodfellow description. Chondral lesions were observed at Gooodfellow areas FCA-3 in 2 dancers, FCA-4 in 5 dancers, PCA-2 in 10 dancers, PCA-3 in 10 dancers, and PCA-4 in 9 dancers. Dance styles that include frequent deep flexions and strolling on a flexed knee joint may be risk factors for chondral lesions in the contact area of the femur in male dancers.