Patellofemoral Joint Alignment Research Articles

Study on the correlation between the severity of patellofemoral arthritis and the morphology of the distal femur

PurposeDistal femoral torsion is a key factor for poor alignment of patellofemoral joint. This study aims to evaluate the correlation between distal femoral torsion and the severity of patellofemoral arthritis, and to analyze the correlation between distal femoral torsion and the morphology of femoral condyle.MethodsA retrospective analysis was performed on 125 patients awaiting surgical treatment for knee osteoarthritis from January 2021 to March 2022(79 females, 46 males, average age: 65.78 years, SD 6.61). All patients underwent knee joint radiography, lower-limb digital radiography, and knee joint CT scans. The ratio of length of each distal femoral condyle, TT-TG, patellar tilt, DFL-PCL, DFL-TEA, TEA-PCL and TEA-ACL were measured. The Pearson correlation coefficient was used to evaluate the correlation between distal femoral torsion and ratio of distal femoral condyle, TT-TG and patellar tilt. Logistic regression was used to evaluate the correlation between each parameter and the severity of PFOA.ResultsWith the increased severity of PFOA, TT-TG, patellar tilt, DFL-PCL, DFL-TEA and PCA all tended to increase. Patellar tilt was correlated with DFL-PCL (r = 0.243) and TEA-PCL(r = 0.201), but TT-TG had no evident correlation with distal femoral torsion. Compared with Grade I patients of PFOA, DFL-PCL, DFL-TEA, and TEA-PCL were risk factors for increased severity of patellofemoral arthritis in Grade III patients of PFOA, but there was no significant statistic difference in Grade II patients of PFOA.ConclusionsDistal femoral torsion correlates with the severity of patellofemoral arthritis. Variation of the femoral transepicondylar axis caused by the change of ratio of the femoral condyle is particularly important in the distal femoral torsion. In patients with severe PFOA, abnormal variation of the femoral condyle axis should be not ignored.

The association between patellofemoral alignment and osteoarthritis in magnetic resonance imaging.

ObjectivesOsteoarthritis (OA) is the most common joint disease in the world, becoming more prevalent with increasing age, and causes a significant burden on individuals and society. So far, several factors have been identified in association with OA of the knee joint. Age is the most crucial uncontrollable risk factor for OA. There are conflicting results regarding the relationship between patellofemoral joint orientation and OA. This study aims to elucidate the relationship between patellofemoral joint alignment and OA evidence.Material and methodsA total of 277 MRIs performed at Imam Reza Hospital during the first half of 2017 were included. Patients were divided into two groups, under 50 years old and over 50 years old. Femoral sulcus angle (SA) and depth (SD), lateral patellar displacement (LPD), tibial tubercle-trochlear groove (TTTG), lateral patellofemoral angle (LPFA), and Insall-Salvati index were measured in axial and sagittal images. The morphology of the patellofemoral articular cartilage was evaluated and the grade of joint damage was determined. P-value < 0.05 was considered as significant.ResultsSignificant correlations between SA (p-value = 0.01), SD (p-value < 0.001), Insall-Salvati index (p-value < 0.001), LPD (p-value = 0.02) values and OA in patients less than 50 years old were observed. A weak correlation was observed between SD and Insall-Salvati index values with increasing grade of articular cartilage damage (r = 0.21 and r = 0.21, respectively).ConclusionsPatellofemoral joint asymmetry in the younger people was significantly associated with joint cartilage damage and premature patellofemoral joint OA. Joint misalignment by stressing the articular cartilage causes joint cartilage changes that may be congenital or due to bone injuries such as trauma and surgery.

Association of patellofemoral morphology and alignment with the radiographic severity of patellofemoral osteoarthritis

BackgroundRisk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA.MethodsA retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic grade of PFOA and tibiofemoral osteoarthritis (TFOA), lateral and medial trochlear inclination angle, sulcus angle, and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG) and patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters, and the relationships between each of these measures and the severity of PFOA were investigated.ResultsBy studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P < 0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle; and type I patella was 8.80 (p = 0.043), 16.51 (P < 0.001), 0.04 (P < 0.001), and 0.18 (p = 0.048) respectively.ConclusionsExtreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.

Retro-Tubercle Biplanar Opening Wedge High Tibial Osteotomy Is Favorable for the Patellofemoral Joint But Not for the Osteotomized Tubercle Itself Compared With Supra-Tubercle Osteotomy

To identify whether retro-tubercle opening-wedge high tibial osteotomy (RT-OWHTO) produces more favorable radiographic outcomes on patellofemoral joint alignment and clinical outcomes than supra-tubercle opening-wedge high tibial osteotomy (ST-OWHTO). From January 2017 to July 2018, patients who underwent biplanar OWHTO were allocated to 1 of 2 groups (ST-OWHTO and RT-OWHTO). Plain radiographs and computed tomography were used to analyze patellofemoral alignment and other radiologic parameters representing osteotomy configurations. Clinical outcomes were assessed using American Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index. In total, 50 knees that underwent ST-OWHTO and 44 knees that underwent RT-OWHTO were enrolled. Patellar height was significantly decreased only after ST-OWHTO (Caton-Deschamps ratio: P= .007; Blackburne-Peel ratio: P= .012). Patellar tilt angle was decreased in both groups (P= .009 and .004, respectively). Postoperative posterior tibial slope (PTS) (P= .013), PTS (Δ) (P < .001), retro-tuberosity gap distance (P= .001), and retro-tuberosity tip distance (P= .001) were significantly larger in RT-OWHTO. Retro-tuberosity tip distance was significantly correlated with retro-tuberosity gap distance (P= .002), thickness of second plane osteotomy fragment (P=.027), and anterior osteotomy ratio (P= .031) in ST-OWHTO. In RT-OWHTO, it was significantly correlated with PTS (△) (P < .001), retro-tuberosity gap distance (P < .001), and sagittal angle of bi-planar osteotomy (P= .005). There were 2 cases of tibial tuberosity fracture, 9 cases of delayed union on second plane osteotomy and 5 cases of tuberosity protrusion in RT-OWHTO. Although the RT-OWHTO technique maintains patellofemoral joint alignment, no difference in clinical outcome was detected. The RT-OWHTO has increased risk of tuberosity fracture, delayed union, and prominent tibial tuberosity. The surgeon should consider these negative aspects of the technique and consider adjusting additional stabilization. Level III, retrospective cohort study.

Preoperative Condition of the Patellofemoral Joint Does Not Negatively Impact Surgical Outcomes of Lateral Unicompartmental Knee Arthroplasty in the Short Term.

The relationship between patellofemoral joint (PFJ) degeneration and clinical outcomes following lateral unicompartmental knee arthroplasty (UKA) has not been well described thus far. This study aimed to investigate the relationship between the preoperative PFJ condition and postoperative outcomes and the changes in lower-limb and PFJ alignment after lateral UKA. This was a retrospective study including 54 patients (mean age 72.9 years) who underwent lateral UKA for isolated lateral knee osteoarthritis at our institution between March 2013 and January 2019. The Oxford Knee Score (OKS), the Knee Society Score-Knee (KSSK), and Knee Society Score-Function (KSSF), the degree of degeneration, tilting angle and lateral shift of the PFJ, and the hip-knee-ankle angle (HKA) were evaluated pre- and postoperatively. The average follow-up period was 2.8 (range 1-6.1) years. There was a significant improvement in the OKS, KSSK, and KSSF after lateral UKA. Preoperative degeneration of the PFJ did not correlate with the recovery of clinical scores. The degeneration, tilting angle, and lateral shift of the PFJ did not significantly progress following lateral UKA. The HKA was improved after lateral UKA, and there was no correlation between the HKA change and PFJ condition. Postoperative severe valgus knee alignment was associated with a greater tilting angle. Preoperative degeneration of the PFJ did not have a negative impact on postoperative outcomes, and no short-term changes in the degeneration, tilting angle, and lateral shift of the PFJ were observed. Correction of knee-joint alignment did not have a negative impact on the condition of the PFJ.

Clinical outcomes after medial patellofemoral ligament reconstruction: an analysis of changes in the patellofemoral joint alignment.

Medial patellofemoral ligament (MPFL) reconstruction using the hamstring tendon is widely performed to treat recurrent patellar dislocation. MPFL reconstruction includes a post-operative process of necrosis and reperfusion of the hamstring tendon graft. We hypothesise that the patella gradually shifts laterally because of this process, ultimately affecting the patellofemoral joint alignment. This study aimed to analyse the chronological changes in the patellofemoral joint alignment and the outcomes of MPFL reconstruction. In this retrospective case-series study, the Knee Society, Lysholm, and Kujala scores were evaluated in 24 consecutive patients (27 knees). To evaluate patellar tracking defects, radiographic indices including the tilting angle, the lateral shift ratio, and the congruence angle were measured before, immediately after, and three, 12, and 36 months after MPFL reconstruction. Post-operative Kujala, KneeSociety, and Lysholm scores for the study population significantly improved relative to the pre-operative scores. The tilting and congruence angles at threemonths after the operation significantly increased relative to those recorded immediately after the operation. The tilting and congruence angles were not significantly different at three, 12, and 36 months after the operation. The post-operative outcomes of MPFL reconstruction for recurrent patellar dislocation were favourable. Insufficient union between the bone tunnel and tendon graft, along with an elongation of the necrotic tendon graft, may change the alignment of the patellofemoral joint within threemonths after the operation. Therefore, we believe it is necessary to refrain from knee rotation that places lateral stress on the patella until threemonths after the operation.

Comparisons of patellar bone mineral density between individuals with and without patellofemoral pain

BackgroundAlthough bone stress injuries have been reported in individuals with patellofemoral pain (PFP), especially within the lateral patella, it remains unclear whether persons with PFP exhibit altered patellar regional bone mineral density (BMD). The primary purpose of this study was to compare BMD of the patella (lateral, medial, and total regions) between individuals with and without PFP using quantitative computed tomography (QCT). The secondary aim was to examine the associations between patellar regional BMD and patellofemoral joint (PFJ) alignment. MethodsTen individuals with retropatellar pain and 10 sex, age, weight, height, and activity matched pain-free controls underwent a QCT scan to obtain patellar BMD. To quantify PFJ alignment, patellar lateral displacement was measured using bisect-offset (BSO) index and patellar mediolateral tilt was quantified using patellar tilt angle (PTA). A two-factor repeated-measures ANOVA was used to compare BMD across the three patellar regions and between the two groups. Pearson correlation coefficient analyses were used to evaluate the associations between BMD and PFJ alignment of all participants. ResultsThere was no difference in BMD between the two groups. However, BMD was highest within the lateral patella and was lowest within the medial patella across both groups. There were significantly moderate to large correlations between BSO index/PTA and BMD within lateral, medial, and total regions. ConclusionsWhile individuals with PFP and pain-free controls have similar patellar BMD, the lateral patella exhibits the highest BMD. Additionally, higher patellar regional BMD is related to increased patellar lateral displacement and lateral tilt.

A Knee Size-Independent Parameter for Malalignment of the Distal Patellofemoral Joint in Children.

Introduction Patellar instability (PI) is a common finding in children. Current parameters describing patellofemoral joint alignment do not account for knee size. Additionally, most parameters utilize joint-crossing tibiofemoral landmarks and are prone to errors. The aim of the present study was to develop a knee size-independent parameter that is suitable for pediatric or small knees and determines the malpositioning of the distal patellar tendon insertion solely utilizing tibial landmarks. Methods Sixty-one pediatric knees were included in the study. The tibial tubercle posterior cruciate ligament distance (TTPCL) was measured via magnetic resonance imaging (MRI). The tibial head diameter (THD) was utilized as a parameter for knee size. An index was calculated for the TTPCL and THD (TTPCL/THD). One-hundred adult knees were analyzed to correlate the data with a normalized cohort. Results The THD was significantly lower in healthy females than in males (69.3 mm ± 0.8 mm vs. 79.1 mm ± 0.7 mm; p < 0.001) and therefore was chosen to serve as a knee size parameter. However, no gender differences were found for the TTPCL/THD index in the healthy adult study cohort. The TTPCL/THD was significantly higher in adult PI patients than in the control group (0.301 ± 0.007 vs. 0.270 ± 0.007; p=0.005). This finding was repeated in the PI group when the pediatric cohort was analyzed (0.316 ± 0.008 vs. 0.288 ± 0.010; p=0.033). Conclusion The TTPCL/THD index represents a novel knee size-independent measure describing malpositioning of the distal patellar tendon insertion determined solely by tibial landmarks.

Two approaches to evaluate the associations between patellofemoral joint alignment, morphology, radiographic osteoarthritis and anterior knee pain: the most study

Purpose: To evaluate the cross-sectional associations between patellofemoral joint alignment, trochlear morphology, radiographic osteoarthritis (OA), and frequent isolated anterior knee pain (AKP). Methods: We evaluated participants from the Multicenter Osteoarthritis Study (MOST), a cohort of 3026 individuals aged 50 - 79 years who had, or were at risk of, knee OA at enrollment. At the 60-month visit, we assessed patellar alignment and trochlear morphology from MR images (bisect offset , patellar tilt angle, sulcus angle, lateral trochlear inclination, medial trochlear inclination, trochlear angle) or lateral radiographs (Insall-Salvati ratio). Radiographic OA was defined on the lateral view (patellofemoral) as any osteophyte ≥ Grade 2, or joint space narrowing ≥ Grade 2 plus any osteophyte, sclerosis or cyst ≥ Grade 1; and OA on the postero-anterior view (tibiofemoral) radiographs was defined as Kellgren & Lawrence ≥ Grade 2. Frequent isolated AKP was defined as: (i) a response of ‘yes’ to the question “During the past 30 days, have you had pain, aching, or stiffness in your knee on most days?”; and (ii) the pain was reportedly isolated to the anterior knee region using a knee pain map. We used two different study designs. Our first design was a within-person, knee-matched evaluation of participants with frequent isolated AKP in one knee and no pain in the other knee (conditional logistic regression). We selected individuals with unilateral knee pain at the 60-month visit, or at the 84-month visit if they did not meet these criteria at 60 months. Our second design was a traditional cohort approach using data from the 60-month study visit, in which we evaluated the relation of the various exposures to presence of frequent isolated AKP to knees without pain (binomial regression). Results: The within-person knee-matched design (n=110, 64% women, mean [SD] age 70 [8], BMI 30.9 [6.3]) revealed no associations between patellofemoral alignment, morphology, or tibiofemoral OA and frequent isolated AKP. Patellofemoral OA was associated with frequent isolated AKP, odds ratio 5.3 (95% CI 1.6, 18.3) (see Table 1). The cohort design (n=1818, 59% women, age 68 [8], BMI 30.4 [5.9]) revealed similar results: only patellofemoral OA was associated with frequent isolated AKP, prevalence ratio 2.2 (1.4, 3.4) (see Table 2). Conclusions: Patellofemoral alignment and trochlear morphology were not associated with frequent isolated anterior knee pain in individuals with, or at risk for, knee OA. Radiographic patellofemoral OA, but not tibiofemoral OA, was associated with frequent isolated anterior knee pain. Features of patellofemoral OA, more so than mechanical alignment or morphology features or tibiofemoral OA, may contribute to localized anterior knee pain.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Are Patellofemoral Joint Alignment and Shape Associated With Structural Magnetic Resonance Imaging Abnormalities and Symptoms Among People With Patellofemoral Pain?

Background: Patellofemoral malalignment has been observed among people with patellofemoral pain (PFP) and may be associated with the presence of imaging features of osteoarthritis, symptoms, and function. Purpose: To determine whether patellofemoral joint alignment and bony shape are associated with (1) cartilage, bone, and soft tissue morphological abnormalities defined on magnetic resonance imaging (MRI) and (2) reported symptoms and function among people with PFP. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Participants (mean ± SD age, 30.2 ± 9.5 years; range, 14-50 years; 78 females, 58.6%) completed questionnaires regarding demographics, pain, symptoms, and function and underwent a 3-T MRI scan of their more symptomatic eligible knee. Structural MRI abnormalities were scored with the MOAKS (Magnetic Resonance Imaging Osteoarthritis Knee Score), and MRI alignment and shape were measured with standardized methods. Associations among MOAKS features, PFP symptoms, and alignment and shape measures were evaluated with regression analyses (α = .05). Results: Minor cartilage defects were present in 22 (16.5%) participants, patellar osteophytes in 83 (62.4%), anterior femur osteophytes in 29 (21.8%), Hoffa synovitis in 81 (60.9%), and prefemoral fat pad synovitis in 49 (36.8%). A larger Insall-Salvati ratio was significantly associated with the presence of patellar osteophytes (odds ratio [OR], 51.82; 95% CI, 4.20-640.01), Hoffa synovitis (OR, 60.37; 95% CI, 4.66-782.61), and prefemoral fat pad synovitis (OR, 43.31; 95% CI, 4.28-438.72) in the patellofemoral joint. A larger patellar tilt angle was significantly associated with the presence of minor cartilage defects (OR, 1.10; 95% CI, 1.00-1.20), the presence of patellar osteophytes (OR 1.12; 95%CI 1.02-1.22), and prefemoral fat pad synovitis (OR, 1.11; 95% CI, 1.03-1.20) in the patellofemoral joint. Finally, a larger bisect offset was significantly associated with the presence of minor cartilage defects (OR, 1.05; 95% CI, 1.00-1.11) and patellar osteophytes (OR, 1.07; 95% CI, 1.01-1.14) in the patellofemoral joint. The majority of patellofemoral alignment measures were not associated with symptoms or function. Conclusion: For people with PFP, the presence of morphological abnormalities defined on MRI appears to be related to particular patellofemoral alignment measures, including higher Insall-Salvati ratio (indicating patella alta), larger patellar tilt angle (indicating greater lateral tilt), and larger bisect offset (indicating greater lateral displacement). Hardly any associations were found with symptoms or function. So there might be a distinct subgroup of PFP that is more prone to developing patellofemoral osteoarthritis later in life, as particular alignment measures seem to be associated with the presence of patellar osteophytes. Prospective studies are required to investigate the longitudinal relationship between alignment or bony shape and morphological abnormalities defined on MRI in this patient population.

Lateral retinacular release via a prolonged incision versus arthroscopic lateral retinacular release in osteofascial medial patellofemoral ligament reconstruction for recurrent patellofemoral dislocation

Objective To compare the short-term outcomes between lateral retinacular release (LRR) via a prolonged incision versus arthroscopic LRR in osteofascial medial patellofemoral ligament reconstruction (MPFL-R) for recurrent patellofemoral dislocation. Methods From May 2012 to March 2015, 51 patients with recurrent patellofemoral dislocation were treated at the Department of Joint Surgery, The Third Affiliated Hospital to Hebei Medical University. They were 16 males and 35 females, aged from 20 to 36 years (mean 27.2 years). Of them, 28 underwent LRR via a prolonged incision in MPFL-R (incision group) and 23 did arthroscopic LRR in MPFL-R (microscopic group). Imaging changes were assessed by comparing preoperative and postoperative values of patella extensibility, patellar tilt angle, trochlear groove angle and tibial tuberosity-trochlear groove spacing (TT-TG); the knee joints were scored with Kujala and Lysholm functional rating systems at the last follow-ups. Results The 2 groups were compatible due to insignificant differences in the general data between them preoperatively (P>0.05). The 51 patients were followed up for 10 to 32 months (average, 20 months). The rate of dislocation in the incision and microscopic groups were 0 and 8.7% (2/23), respectively. There were no such complications in either group as patellar fracture, deep venous thrombosis of the lower extremity or limited joint extension or flexion. The last follow-ups revealed that no patients in either group were inflicted with patellofemoral re-dislocation. In the incision group, the patella extensibility, patellar tilt angle, Kujala score and Lysholm score were, respectively, 19.65%±0.75%, 12.39°±0.76°, 56.37±2.94 points and 51.64±6.22 points preoperatively, and 10.34%±0.60%, 8.83°±0.89°, 92.68±2.75, and 90.71±1.91 points postoperatively; in the microscopic group, the patella extensibility, patellar tilt angle, Kujala score and Lysholm score were, respectively, 19.56%±0.62%, 12.35°±0.66°, 57.46±3.08 points and 52.20±6.94 points preoperatively, and 10.24%±0.66%, 8.78°±0.92°, 92.53±3.32 points and 90.41±2.90 points postoperatively. There were significant differences between the preoperative and postoperative values in both 2 groups (P 0.05). There were no significant differences between the 2 groups in all the above preoperative and postoperative values (P>0.05). Conclusion In MPFL-R for recurrent patellofemoral dislocation, both LRR via a prolonged incision and arthroscopic LRR can improve the patellofemoral joint alignment and stability of the tibia, leading to good short-term outcomes. Key words: Arthroscopy; Patellar ligament; Patellar dislocation; Lysis

Imaging of Juvenile Hip Conditions Predisposing to Premature Osteoarthritis-Erratum.

HomeRadioGraphicsVol. 38, No. 2 PreviousNext ErrataFree AccessImaging of Juvenile Hip Conditions Predisposing to Premature Osteoarthritis—ErratumCarl Kraus, Rama S. Ayyala, Jonathan K. Kazam, Tony T. WongCarl Kraus, Rama S. Ayyala, Jonathan K. Kazam, Tony T. WongCarl KrausRama S. AyyalaJonathan K. KazamTony T. WongPublished Online:Mar 12 2018https://doi.org/10.1148/rg.2018174019MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Originally published in:RadioGraphics 2017;37(7):2204–2205 • https://doi.org/10.1148/rg.2017170067Imaging of Juvenile Hip Conditions Predisposing to Premature OsteoarthritisCarl Krsaus, Rama S. Ayyala, Jonathan K. Kazam, Tony T. WongErratum in:RadioGraphics 2018;38(2):662 • https://doi.org/10.1148/rg.2018174019Supplemental presentation, slide 8: The line beginning with “Acetabular line” should read as follows: “Acetabular line: Drawn connecting the superolateral acetabular roof to the ipsilateral triradiate cartilage (angle formed with horizontal line should be less than [not greater than] 30°).”Article HistoryPublished online: Mar 12 2018Published in print: Mar 2018 FiguresReferencesRelatedDetailsCited ByMedium-term outcomes of total hip arthroplasty in juvenile patientsFrancescoLuceri, IlariaMorelli, Carlo MariaSinicato, AlbertoDella Grazia, FabioVerdoni, NicolaMaffulli, Giuseppe M.Peretti, DomenicoCurci2020 | Journal of Orthopaedic Surgery and Research, Vol. 15, No. 1Accompanying This ArticleImaging of Juvenile Hip Conditions Predisposing to Premature Osteoarthritis: Pediatric ImagingNov 13 2017RadioGraphicsRecommended Articles Hip Imaging in Athletes: Sports Imaging SeriesRadiology2016Volume: 280Issue: 2pp. 351-369Developmental Hip Dysplasia Diagnosis at Three-dimensional US: A Multicenter StudyRadiology2018Volume: 287Issue: 3pp. 1003-1015Radiography, CT, and MRI of Hip and Lower Limb Disorders in Children and AdolescentsRadioGraphics2019Volume: 39Issue: 3pp. 779-794Relationship of Trochlear Morphology and Patellofemoral Joint Alignment to Superolateral Hoffa Fat Pad Edema on MR Images in Individuals with or at Risk for Osteoarthritis of the Knee: The MOST StudyRadiology2017Volume: 284Issue: 3pp. 806-814Imaging of Sports-related Injuries of the Lower Extremity in Pediatric PatientsRadioGraphics2016Volume: 36Issue: 6pp. 1807-1827See More RSNA Education Exhibits Developmental Dysplasia of the Hip: Clinical and Imaging Findings for Early Diagnosis and TreatmentDigital Posters2018To Correctly Understand the Graf Classification—Recognize the Relationship of the Black Ball to the White WallDigital Posters2020Adult Hip Dysplasia - An Updated Imaging ApproachDigital Posters2020 RSNA Case Collection Developmental hip dysplasia RSNA Case Collection2021Osteoarthritis of L hipRSNA Case Collection2020Patella FractureRSNA Case Collection2020 Vol. 38, No. 2 Metrics Altmetric Score PDF download

Is the effectiveness of patellofemoral bracing modified by patellofemoral alignment and trochlear morphology?

BackgroundThis study was performed to determine if the effectiveness of patellofemoral bracing as a treatment for patellofemoral osteoarthritis is influenced by patellofemoral joint alignment and trochlear morphology. We hypothesized that those with more extreme patellar malalignment would benefit more from bracing.MethodsThirty-eight patients who had received bracing as part of a comprehensive treatment plan for patellofemoral osteoarthritis were selected for this study. Ten measures of patellar alignment were taken from X-rays. These alignment measures were divided into percentile groups (tertiles) for contingency table analysis. Treatment outcome was measured by Western Ontario and Macmasters Universities Osteoarthritis Index (WOMAC) scores and these were dichotomised into two groups according to “Improved” or “Not Improved” according to the minimum clinically important difference (MCID). Spearman’s rho test was performed for continuous variables and Fisher’s exact test was performed for correlation between tertile groups and MCID categories.ResultsThirty-eight patients (9 male and 29 female) between the ages of 51 to 89 were included in this study. WOMAC scores ranged from −25 to 41.67, with a mean change of −3.97, 31.6, 44.7 and 31.6% of patients falling into the “Improved” group for Global, Pain and Function scores respectively. We found a non-significant trend shown (p = 0.058, correlation coefficient 0.31) between bisect offset and change in WOMAC global, indicating a trend for higher change in WOMAC scores with increasing bisect offset. Statistically significant correlations were found between mean MCID categories for the WOMAC global and function groups when analysed against percentile groups for bisect offset (p < 0.01) and patellar subluxation distance (p < 0.05), indicating those in higher percentile groups were more likely not to improve after six months.ConclusionHigher bisect offset and patellar subluxation distance measures were associated with poorer outcomes. However, due to the limited sample size, more studies are required to fully examine this relationship.

Relationship of Trochlear Morphology and Patellofemoral Joint Alignment to Superolateral Hoffa Fat Pad Edema on MR Images in Individuals with or at Risk for Osteoarthritis of the Knee: The MOST Study.

Purpose To determine the relationship of patellofemoral joint alignment and trochlear morphology to superolateral Hoffa fat pad (SHFP) edema on magnetic resonance (MR) images in older adults with or at risk for osteoarthritis of the knee. Materials and Methods Institutional review board approval and written informed consent were obtained from all subjects. The Multicenter Osteoarthritis Study is a prospective cohort study of older adults with or at risk for osteoarthritis of the knee. Subjects were recruited from Birmingham, Alabama, and Iowa City, Iowa. In this cross-sectional study, patellofemoral joint alignment (bisect offset, patellar tilt angle, and Insall-Salvati ratio), trochlear morphology (sulcus angle, lateral and medial trochlear inclination, and trochlear angle) and SHFP edema were assessed on MR images of the knee. Measures of alignment and morphology were divided into quartiles, and SHFP was determined to be present or absent. Separate logistic regression models were used to determine the relationship of each measure of alignment and morphology to the presence of SHFP edema, with adjustments for age, sex, and body mass index. Results SHFP edema was present in 152 (13.4%) of the 1134 knees that were included. When compared with knees with measurements in the lowest quartile, knees with measurements in the highest quartile for trochlear angle, bisect offset, and Insall-Salvati ratios were 1.6 (95% confidence interval [CI]: 1.0, 2.6), 2.3 (95% CI: 1.3, 4.0), and 8.9 (95% CI: 4.7, 16.9) times more likely to show SHFP edema, respectively. No relationship was found between other measures and SHFP edema. Conclusion A more anterior trochlear facet, a more laterally displaced patella, and knees with patella alta were significantly associated with SHFP edema on MR images in subjects with or at risk for osteoarthritis of the knee. © RSNA, 2017.

Relationship between Patellar Tracking and the "Screw-home" Mechanism of Tibiofemoral Joint.

To demonstrate the effect of the screw-home motion on the stability of the patellofemoral joint, and investigate its mechanism of regulation of patellar tracking. Twenty volunteers who met the criteria were examined. All subjects had axial computed tomography (CT) scanning performed on bilateral knees at 0° and 30° of flexion. Scanning began above the femorotibial articulation and femoral trochlear groove, and moved sequentially down to the level of the anterior tibial tubercle. The following measurements were obtained: tibial rotation relative to the femur (TRRF), tibial tuberosity-trochlear groove (TT-TG) distance, lateral patellar displacement (LPD), patellar tilt angle (PTA), and congruence angle (CA). We assessed the change (Δ) in each variable at both flexion angles, and analyzed this to investigate the corresponding relationship between the patella, the femur, and the screw-home mechanism. The differences between the values measured at 0° and those measured at 30° flexion were analyzed using the paired sample t-test. The differences between men and women were analyzed using the t-test. Pearson's correlations were performed to determine the relationship between ΔTT-TG distance and ΔLPD, ΔPTA and ΔTRRF, and ΔCA and ΔTRRF. There were 10 women and 10 men enrolled in the present study, with an average age of 25 years and an average body mass index of 21.8 kg/m2 , and all volunteers had no history of knee injuries. Compared with measurements taken at 0° flexion, TRRF at 30° flexion was significantly increased, and the PTA, CA, LPD, and TT-TG distance were significantly decreased (all P < 0.01). There was no difference between men and women at 0° and 30° flexion, respectively (P < 0.01). In this respect, there was no sex difference, but the change was greater for men than for women. Both ΔPTA and ΔCA demonstrated significant correlation with the ΔTRRF (both P < 0.01); a significant correlation between ΔLPD and ΔTT-TG distance was also demonstrated (P < 0.01). As the tibiofemoral joint rotated, the patellofemoral joint became more stable and aligned, which indicates that the screw-home mechanism plays an important role in regulating patellofemoral joint alignment.

Medial Patellofemoral Ligament Reconstruction Combined With Distal Realignment for Recurrent Dislocations of the Patella: 5-Year Results of a Randomized Controlled Trial

Background: Tibial tubercle transfer (TTT) and medial patellofemoral ligament (MPFL) reconstruction have both shown, either in isolation or in combination, to provide improved patellofemoral joint (PFJ) stability. There are few studies that provide evidence that this remains true in the long term. Purpose: To compare the long-term results of patellar instability after TTT with and without MPFL reconstruction in 2 randomized groups. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 34 patients (36 knees) were randomized to 2 groups. The first group underwent lateral release (LR) and TTT for confirmed maltracking of the patella (control group). The second group underwent MPFL reconstruction in addition to TTT and LR (reconstruction group). Patients were followed up with validated questionnaires (Kujala score, Tegner activity score), a visual analog scale (VAS) assessing their insecurity, and a clinical assessment at a minimum of 5 years postoperatively. Participants also underwent quantitative computed tomography (CT) at 1 year for comparison. Two patients in the control group and 1 patient in the reconstruction group were lost to follow-up at 5 years. Results: There were no significant differences in the Kujala (P = .75), Tegner (P = .36), or VAS (P = .75) scores at any time period. One patient in the control group sustained a patellar redislocation at 3 years. Five patients in the control group and 2 in the reconstruction group had functional failures and required reoperations; however, this was not statistically significant (P = .30). There were no significant differences between groups in the time to return to school or work (P = .65) or sports (P = .38) after surgery. Overall patient satisfaction was higher in the reconstruction group compared with the control group (P = .04), and quantitative CT scans showed that the reconstruction group had a statistically significant improvement in the mean patellar tilt (6° vs −8°, respectively; P = .03) and mean congruence angle (13° vs −11°, respectively; P = .03) in the quadriceps-contracted state compared with the control group. Conclusion: Reconstruction of the MPFL in addition to TTT and LR resulted in improved alignment parameters (congruence angle, patellar tilt angle) as well as patient satisfaction. The Kujala and Tegner scores were no different between the 2 groups at any time period. There was insufficient evidence to conclude that the addition of MPFL reconstruction to TTT results in fewer redislocations or reoperations. This study concludes that MPFL reconstruction improves PFJ alignment and patient satisfaction; however, further studies with larger patient numbers are required to satisfy its significance with respect to redislocation rates and functional scores in the long term.

Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella.

The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis. Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3-4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella-patellar tendon angle (P-PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P-PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P-PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis. The mean age of all participants was 52.9±8.2years. The mean P-PT angle was significantly lower in chondromalacia group (142.1°±3.6°) compared to control group (144.5°±5.3°) (p=0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P-PT angles in patients with superior (141.8±2.7) and inferior subgroups (139.2±2.3) were significantly lower than the values in the control group (p<0.05). The contact area values were detected higher in models with chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models. This study revealed that sagittal plain malpositioning of the patellofemoral joint might be related to chondromalacia, especially in the presence of lesions in the upper and lower part of the patella. This condition leads to supraphysiological loadings on the patellofemoral joint. Sagittal patellar tilt should be considered in the evaluation and management of patellar cartilage defects. Taking sagittal plane malalignment into consideration in patellofemoral joint evaluation will enable us to design new physical and surgical modalities. IV.

The relation of patellofemoral joint alignment and trochlear morphology to superolateral Hoffa’s fat pad edema: the most study

Purpose: The infrapatellar or Hoffa’s fat pad (HFP) is an intracapsular but extrasynovial fat tissue in the knee joint located inferior to the patella and posterior to the patellar tendon. It is highly innervated and may be a source of knee pain. Impingement of HFP between the lateral femoral condyle and the patellar tendon is hypothesized to cause inflammation/edema in the superolateral region of HFP. This impingement may be a result of patellofemoral joint (PFJ) alignment and abnormal trochlear morphology. Previous studies in young individuals have demonstrated conflicting results as to which measures of PFJ alignment and trochlear morphology are related to superolateral HFP edema. More generalized inflammation/edema in HFP is present in older individuals with knee osteoarthritis (OA). The aim of the current study was to assess whether measures of PFJ alignment and trochlear morphology are related to superolateral HFP edema and if superolateral HFP edema is related to knee pain in older individuals with or at risk for knee OA. Methods: The Multicenter Osteoarthritis (MOST) study is a NIH-funded longitudinal cohort study of older individuals with or at risk for knee OA. For the current cross-sectional study we used data from the 60-month study visit where all eligible subjects had their knee MRI assessed for other structural features of knee OA. Signal changes in three areas (superolateral, infrapatellar and intercondylar) of HFP were assessed on sagittal proton density-weighted fat-suppressed MRI images from 0 to 3 (0 = normal, 1 = mild, 2 = moderate, 3 = severe) by two musculoskeletal radiologists and dichotomized into presence (>1) and absence (=0). PFJ alignment (bisect offset and patellar tilt angle) and trochlear morphology (lateral trochlear inclination, sulcus angle and trochlear angle) were assessed on axial MRI images and divided into quintiles. Subjects were also queried about the presence of frequent knee pain (FKP) defined as pain on most days of the last month. We determined the relation of measures of PFJ alignment and trochlear morphology to the presence of superolateral HFP edema using logistic regression, adjusting for age, sex and body mass index. We additionally determined the relation of superolateral HFD edema to FKP using logistic regression, adjusting for age, sex, body mass index, depressive symptoms, catastrophizing and presence of signal changes in the infrapatellar/intercondylar HFP. Results: To date, 433 knees have been assessed for PFJ alignment, trochlear morphology and superolateral HFP edema. Superolateral HFP edema was present in 63 (17.7%) of knees. Compared with knees in the lowest quartile of bisect offset, those in the highest had 6.4 (2.6, 15.7) times the odds of having superolateral HFP edema. Compared with knees in the lowest quartile of trochlear angle, those in the highest had 2.7 (1.2, 6.3) times the odds of having superolateral HFP edema. There was no relation of other PFJ alignment/trochlear morphology measures to superolateral HFP edema. There was also no relation of superolateral HFP edema to FKP. Conclusions: Knees with the greatest lateral displacement of the patella had the greatest odds of superolateral HFP edema. Treatments that attempt to normalize PFJ alignment may help to reduce the prevalence of superolateral HFP edema.Tabled 1Table. Relation of PFJ alignment and trochlear morphology to superolateral HFP edema% Patella lateral to midline (Bisect Offset)Quartile 1Quartile 2Quartile 3Quartile 4Range33.91–52.5952.6–58.1658.17–64.664.61–92.79# of knees108109109108Superolateral HFP edema%≥16.511.113.828.7Adjusted OR* (95% CI)1.0 (reference)1.9 (0.70, 5.0)2.5 (0.95, 6.4)6.4 (2.6, 15.7)Trochlear Morpholgy (Trochlear Angle)Quartile 1Quartile 2Quartile 3Quartile 4 (flat trochlea)Range−5.32–0.940.95–3.553.56–5.835.84–26.57# of knees108109109108Superolateral HFP edema%≥18.313.814.724.3Adjusted OR* (95% CI)1.0 (reference)1.6 (0.65, 3.8)1.6 (0.67, 3.9)2.7 (1.2, 6.3)∗Adjusted for age, sex and BMI Open table in a new tab ∗Adjusted for age, sex and BMI

The patellofemoral joint alignment in patients with symptomatic accessory navicular bone

Quadriceps angle (Q angle) provides useful information about the alignment of the patellofemoral joint. The aim of the present study was to assess a possible link between malalignment of the patellofemoral joint and symptomatic accessory navicular (AN) bone as an underlying cause in early adolescence using Q angle measurements. This study was performed on patients presenting to the Foot and Ankle Clinic at the Jordanian Royal Medical Services because of pain on the medial side of the foot that worsened with activities or shoe wearing, with no history of knee pain, between September 2013 and April 2015. The Q angle was measured using a goniometer in 27 early adolescents aged 10-18 years diagnosed clinically and radiologically with symptomatic AN bone, only seven patients had associated pes planus deformity; the data were compared with age appropriate normal arched feet without AN. Navicular drop test (NDT) was used to assess the amount of foot pronation. The mean Q angle value among male and female patients with symptomatic AN with/without pes planus was significantly higher than in controls with normal arched feet without AN (p<0.05). Symptomatic AN feet were also associated with higher NDT values (p<0.001). The present findings suggest an early change in patellofemoral joint alignment in patients with symptomatic AN bone with/without arch collapse. Therefore, it is recommended that Q angle assessment should be an essential component of the examination in patients with symptomatic AN bone.

Dynamic measurement of patello-femoral joint alignment using weight-bearing magnetic resonance imaging (WB-MRI)

ObjectiveAim of our work was to compare standard and weight-bearing WB-MRI to define their contribution in unmasking patello-femoral (PF) maltracking and to define what measurement of patellar alignment is the most reliable. MethodsWe prospectively collected 95 non consecutive patients, clinically divided into 2 groups: group A (the control group), including 20 patients (negative for patellar maltracking), and group B including 75 patients (positive for patellar maltracking). The patients underwent a dedicated 0.25T MRI, in supine and WB position, with knee flexion of 12–15°. The following measurements were performed: Insall-Salvati index (IS), lateral patellar displacement (LPD), lateral patello-femoral angle (LPA) and lateral patellar tilt (LPT). Quantitative and qualitative statistical analyses were performed to compare the results obtained before and after WB-MRI. Measurements were subsequently performed on both groups. ResultsGroup A patients showed no statistically significant variations at all measurements both on standard and WB-MRI. On the basis of measurements made on standard MRI, group B patients were divided into group B1 (23 patients) (negative or positive at 1 measurement) and group B2 (52 patients) (positive at 2 or more measurements). After WB-MRI, group B1 patients were divided into group B1a (6 patients), in case they remained positive at 0/1 measurement, and group B1b (17 patients), in case they became positive at 2 or more measurements. All group B2 patients confirmed to be positive at 2 or more measurements at WB-MRI. Quantitative statistical analysis showed that LPT and LPA were the most reproducible and clinically useful measurements. Qualitative statistical analysis performed on standard and WB-MRI demonstrated that LPT was the best predictive measurement. ConclusionsThis study demonstrates both the high diagnostic value of WB-MRI in unmasking PF-maltracking and the best predictive value of LPT measurement.