Progression Of Patellofemoral Osteoarthritis Research Articles

Deep Learning for Predicting Progression of Patellofemoral Osteoarthritis Based on Lateral Knee Radiographs, Demographic Data, and Symptomatic Assessments.

In this study, we propose a novel framework that utilizes deep learning and attention mechanisms to predict the radiographic progression of patellofemoral osteoarthritis (PFOA) over a period of 7 years. This study included subjects (1,832 subjects, 3,276 knees) from the baseline of the Multicenter Osteoarthritis Study (MOST). Patellofemoral joint regions of interest were identified using an automated landmark detection tool (BoneFinder) on lateral knee X-rays. An end-to-end deep learning method was developed for predicting PFOA progression based on imaging data in a five-fold cross-validation setting. To evaluate the performance of the models, a set of baselines based on known risk factors were developed and analyzed using gradient boosting machine (GBM). Risk factors included age, sex, body mass index, and Western Ontario and McMaster Universities Arthritis Index score, and the radiographic osteoarthritis stage of the tibiofemoral joint (Kellgren and Lawrence [KL] score). Finally, to increase predictive power, we trained an ensemble model using both imaging and clinical data. Among the individual models, the performance of our deep convolutional neural network attention model achieved the best performance with an area under the receiver operating characteristic curve (AUC) of 0.856 and average precision (AP) of 0.431, slightly outperforming the deep learning approach without attention (AUC = 0.832, AP = 0.4) and the best performing reference GBM model (AUC = 0.767, AP = 0.334). The inclusion of imaging data and clinical variables in an ensemble model allowed statistically more powerful prediction of PFOA progression (AUC = 0.865, AP = 0.447), although the clinical significance of this minor performance gain remains unknown. The spatial attention module improved the predictive performance of the backbone model, and the visual interpretation of attention maps focused on the joint space and the regions where osteophytes typically occur. This study demonstrated the potential of machine learning models to predict the progression of PFOA using imaging and clinical variables. These models could be used to identify patients who are at high risk of progression and prioritize them for new treatments. However, even though the accuracy of the models were excellent in this study using the MOST dataset, they should be still validated using external patient cohorts in the future.

Association between patellofemoral osteoarthritis with demographic features and anatomical variants of the knee in non-traumatic patients

Background: Patellofemoral osteoarthritis (PFOA) is a common cause of knee discomfort and impairment, particularly among athletes. The development of PFOA has been associated with anatomical knee variations, such as trochlear dysplasia and patella alta. However, the relationship between these anatomical variants and the development of PFOA remains poorly understood. This study aimed to investigate the association between PFOA and knee anatomical variants in a cohort of patients. Methods: The study included 200 patients with PFOA and 200 healthy controls. In this study, we investigate the relationship of osteoarthritis with both anatomical variants and demographic characteristics. The participants underwent Magnetic resonance imaging (MRI) evaluation of the knee, and anatomical variants including trochlear dysplasia and patella alta were assessed. The severity of PFOA was also graded based on cartilage area and depth, as well as the bone marrow involvement and presence of osteophytes. Results: Statistically significant differences were observed between the two groups in terms of Tibial tuberosity-trochlear groove (TT-TG) distance, patella position, trochlear dysplasia, and Insall-Salvati ratio. The mean TT-TG distance, prevalence of alta patella position, and Insall-Salvati ratio were significantly higher in cases (P<0.001 for all), and cases had a higher incidence of trochlear dysplasia (P<0.001). There were no significant differences between cases and controls regarding patella baja. Conclusion: Anatomical knee variants, including the TT-TG distance, trochlear dysplasia, and Insall-Salvati ratio, are significant risk factors for PFOA progression. The results also indicate that higher BMI and older age are significantly associated with more measures of MRI Osteoarthritis Knee Score (MOAKS) than demographic information. Among anatomical variants, a higher TT-TG distance and an increased grade of trochlear dysplasia show a significant relationship with more measures of MOAKS. Understanding the relationship between these factors has important clinical and research implications and can help inform the development of new treatments.

Patellofemoral Osteoarthritis Progression After Open-Wedge High Tibial Osteotomy Does Not Affect the Clinical Outcomes or Survivorship at Minimum 7 Years’ Follow-Up

The aim of this study was to evaluate the clinical and radiological outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess the effects of patellofemoral osteoarthritis (OA) progression after OWHTO on clinical outcomes at minimum 7 years follow up. We retrospectively reviewed 95 knees that underwent OWHTO and at least seven years of follow-up. Clinical parameters including anterior knee pain, Japanese Orthopedic Association (JOA) score, Oxford knee score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), Hospital for Special Surgery patella score, and KOOS-patellofemoral subscale (KOOS-PF) were evaluated. Radiological outcomes were evaluated preoperatively and at final follow-up. Patellofemoral OA progressions were evaluated using Kellgren-Lawrence grade, and we divided the patients into two groups (progression group and non-progression group) to evaluate the effect of patellofemoral OA progression after OWHTO on long-term clinical outcomes. The mean follow-up period was 10.8 ± 2.6 years (range: 7.6-17.3 years). The mean JOA score significantly improved (from 64.4 ± 11.6 to 90.9 ± 9.3, P < 0.001), and the mean OKS at final follow-up was 40.4 ± 8.3. Due to medial OA progression, five cases were converted to total knee arthroplasty, and the survival rate was 94.7% at 10.8 years of follow-up. Radiologically, patellofemoral OA progression was observed at final follow-up in 48 knees (50.5%). However, there were no significant differences in all clinical outcomes at final follow-up between the progression and non-progression groups. Patellofemoral OA progression may progress over long-term follow-up after OWHTO. Related symptoms are minimal and this does not affect the clinical outcomes or survivorships at minimum 7 years follow-up. Level IV, Therapeutic case series.

Correlation between Open Wedge High Tibial Osteotomy and Progression of Patellofemoral Osteoarthritis (A Systematic Review)

Correlation between Open Wedge High Tibial Osteotomy and Progression of Patellofemoral Osteoarthritis (A Systematic Review)

Association of Infrapatellar Fat Pad Fibrosis at 3 Months After ACL Reconstruction With Short-term Clinical Outcomes and Inflammatory Cytokine Levels in the Synovial Fluid

Infrapatellar fat pad (IFP) fibrosis is reportedly associated with anterior knee pain and the progression of patellofemoral osteoarthritis after anterior cruciate ligament reconstruction (ACLR). However, causes of IFP fibrosis after ACLR have not been sufficiently investigated. To compare the descriptive characteristics, clinical outcomes, and inflammatory cytokine levels in the synovial fluid between patients who underwent ACLR with versus without severe IFP fibrosis. Cohort study; Level of evidence, 3. Patients who underwent primary ACLR using autologous hamstring tendon were divided into 2 groups based on magnetic resonance imaging IFP fibrosis scoring (grades 0-5) at 3 months after surgery: the severe fibrosis group (grades 4 and 5) and mild fibrosis group (grades 0-3). Synovial fluid was aspirated on postoperative day 3 or 4 to measure inflammatory cytokine levels. Patient characteristics, clinical outcomes at 3 and 12 months after surgery, and inflammatory cytokine (interleukin [IL]-1β, IL-2, IL-6, IL-8, IL-10, tumor necrosis factor-α, and interferon-γ) levels were compared between the groups. Of the 36 patients included, 7 were allocated to the severe fibrosis group and 29 were allocated to the mild fibrosis group. The severe fibrosis group had a significantly longer operation time (153.0 vs 116.5 minutes for mild fibrosis; P = .007). Compared with the mild fibrosis group, the severe fibrosis group had greater pain during stair climbing (2.0 vs 0.7; P = .01) and a lower extension muscle strength ratio (operated/healthy side, 52.9% vs 76.1%; P < .001) at 3 months, and the severe fibrosis group had a lower Lysholm score (93.7 vs 97.3; P = .026) and greater knee extension (0.3° vs 1.9°; P = .043) and flexion angle restriction (142.9° vs 149.0°; P = .013) at 12 months. The severe fibrosis group demonstrated higher IL-1β (2.6 vs 1.4 pg/mL; P = .022), IL-6 (2.0 vs 1.1 ng/mL; P = .029), and interferon-γ levels (11.3 vs 4.0 pg/mL; P = .044). Severe IFP fibrosis was associated with a longer operation time, higher inflammatory cytokine level in the synovial fluid, and worse clinical outcomes at 3 and 12 months after ACLR.

Can double-level osteotomy prevent patellofemoral osteoarthritis progression compared with open wedge high tibial osteotomy?

To compare radiographic, clinical, and arthroscopic findings in patellofemoral (PF) osteoarthritis (OA) between open wedge high tibial osteotomy (OWHTO) and double-level osteotomy (DLO) with the same operative indication. After adjustment for patient age, and coronal alignment, 36 knees with OWHTO alone and 36 knees with DLO were compared. Radiographic, clinical, and arthroscopic findings were documented before osteotomy. Arthroscopic findings were observed 1year after osteotomy, and clinical and radiographic findings were observed 2years after osteotomy. Patellar height was evaluated using the Insall-Salvati (IS) ratio, Carton-Deschamps (CD) index, and Blackburne-Peel (BP) index. Lateral patellar tilt and patellar shift were measured. A power analysis was performed. The postoperative CD and BP indices in the OWHTO group were lower than those in the DLO group (p < 0.001 and p = 0.001, respectively). The CD and BP indices in both groups significantly decreased postoperatively (all p < 0.001). Tilting angles in the OWHTO and DLO groups significantly decreased postoperatively (p < 0.001 and p = 0.002, respectively). There were no significant differences in American Knee Society scores, Kujala score, and the Knee Injury and Osteoarthritis Outcome Scores between both groups. The PF OA progression of the trochlear in the OWHTO group was higher than that in the DLO group (p = 0.002), and the PF OA progression of the patellar facet in the DLO group and anterior femoral condyle in both groups on the lateral side were higher than those on the medial side (p = 0.006, 0.032, and 0.041, respectively). DLO decreased the rate of low patellar height compared with OWHTO. DLO decreased the rate of PF OA progression in the trochlea compared with OWHTO. There were no significant differences in clinical outcomes in both groups. Level III, case-control study.

Insall proximal realignment with/without tibial tubercle osteotomy for recurrent patellar instability yields acceptable medium- to long-term results but risk of osteoarthritis progression is considerable

PurposeThe purpose of this study was to evaluate clinical and radiological results in patients operated for recurrent patellar instability with a surgical approach consisting of Insall proximal realignment with/without tibial tubercle osteotomy (TTO).MethodsPatients that underwent surgery for recurrent patellar instability at one centre with a uniform technique between 2004 and 2020 were included. Eligible patients were assessed by clinical examination and the disease-specific Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0). Pre- and postoperative radiographs were analysed for patellofemoral osteoarthritis (OA) according to Iwano. Preoperative Magnetic Resonance Imaging (MRI) and radiographs were analysed for anatomical risk factors for patellar instability. Student t-test, chi-square test and ANOVA-analyses were used to investigate whether anatomical risk factors and/or patient characteristics could predict an inferior outcome.ResultsForty-six patients (47 knees) were included at a mean follow-up time of 6.6 years (SD 4.6; range 1–17). Mean BPII 2.0 score was 60.4 (SD 18.4; range 26–98), and 10.6% (n = 5) had suffered a postoperative redislocation. Progression to evident patellofemoral OA was seen in 15% of the patients (p < 0.05). The presence of pathoanatomic risk factors did not correlate with recurrent postoperative instability or inferior BPII 2.0 score at the final evaluation.ConclusionPatients treated with the current approach reported acceptable medium- to long-term results, but the risk of patellofemoral OA progression is significant. These findings add to the knowledge of expected outcomes after procedures involving Insall proximal realignment, and can guide clinical decision making for surgeons using similar methods.Level of evidenceLevel IV, case series.

UNDERLOADING, NOT OVERLOADING, OF THE PATELLOFEMORAL JOINT INCREASES THE RISK OF EARLY OSTEOARTHRITIS AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Purpose: Approximately 50% of adolescents and young adults who rupture their anterior cruciate ligament (ACL) develop knee osteoarthritis (OA) within 10 years. While most reports of OA after ACL injury focus on the tibiofemoral joint, patellofemoral OA is common and more strongly associated with knee pain and impaired function. The mechanisms underpinning the rapid development and progression of patellofemoral OA after ACL injury are unknown but may relate to the way the knee moves (biomechanics).

Combining advanced computational and imaging techniques as a quantitative tool to estimate patellofemoral joint stress during downhill gait: A feasibility study

BackgroundThe onset and progression of patellofemoral osteoarthritis (OA) has been linked to alterations in cartilage stress—a potential precursor to pain and subsequent cartilage degradation. A lack in quantitative tools for objectively evaluating patellofemoral joint contact stress limits our understanding of pathomechanics associated with OA. Research questionCould computational modeling and biplane fluoroscopy techniques be used to discriminate in-vivo, subject-specific patellofemoral stress profiles in individuals with and without patellofemoral OA? MethodsThe current study employed a discrete element modeling framework driven by in-vivo, subject-specific kinematics during downhill gait to discriminate unique patellofemoral stress profiles in individuals with patellofemoral OA (n = 5) as compared to older individuals without OA (n = 6). All participants underwent biplane fluoroscopy kinematic tracking while walking on a declined instrumented treadmill. Subject-specific kinematics were combined with high resolution geometrical models to estimate patellofemoral joint contact stress during 0%, 25 %, 50 %, 75 % and 100 % of the loading response phase of downhill gait. ResultsIndividuals with patellofemoral OA demonstrated earlier increases in patellofemoral stress in the lateral patellofemoral compartment during loading response as compared to OA-free controls (P = 0.021). Overall, both groups exhibited increased patellofemoral contact stress early in the loading response phase of gait as compared to the end of loading response. Results from this study show increased stress profiles in individuals with patellofemoral OA, indicating increasing joint loading in early phases of gait. SignificanceThis modeling framework—combining arthrokinematics with discrete element models—can objectively estimate changes in patellofemoral joint stress, with potential applications to evaluate outcomes from various treatment programs, including surgical and non-surgical rehabilitation treatments.

Lateral and patellofemoral compartment osteoarthritis progression after medial unicompartmental knee arthroplasty: A five- to 10-year follow-up study

BackgroundThe purpose of the study was to evaluate lateral and patellofemoral osteoarthritis (OA) progression after medial unicompartmental knee arthroplasty (UKA) and identify factors affecting the progression that were not identified previously. MethodsWe evaluated 146 patients who underwent medial UKA between 2009 and 2014. Kellgren–Lawrence grading of lateral and patellofemoral OA was performed on preoperative and final follow-up knee radiographs. Radiographic and clinical characteristics, SF-36, and Oxford knee scores were compared between the OA progressed and non-progressed groups. Risk factors for lateral and patellofemoral OA progression were evaluated. ResultsThe lateral OA progressed and non-progressed groups significantly differed in side, preoperative flexion contracture, preoperative joint line convergence angle, postoperative tibiofemoral angle, insert size, revision status (P < 0.05), and the patellofemoral OA progressed and non-progressed groups significantly differed in age, pre- and postoperative flexion contracture, postoperative tibiofemoral angle and pre- and postoperative patellofemoral OA grade (P < 0.05). At the final follow-up, Visual Analogue Scale, Oxford Knee Scores, and SF-36 sub-scores were significantly better in the lateral OA non-progressed group (P < 0.001).Dominant leg (odds ratio (OR): 2.759), insert size (>4, OR: 2.219), revision status (+, OR: 6.692), and postoperative tibiofemoral angle (>5.5°, OR: 1.177) were independent risk factors for lateral OA progression, whereas age (>60 years, OR: 3.222), preoperative patellofemoral OA grade (>1, OR: 2.085), and postoperative flexion contracture (>10°, OR: 1.919) were those for patellofemoral OA progression. ConclusionsMild radiographic progression of 1 KL grade is frequently seen five to 10 years after medial UKA. Postoperative outcomes are significantly affected by lateral compartment OA progression but not by patellofemoral OA progression.

Comparison of Clinical and Radiological Outcomes Between Transosseous Tunnel and Suture Anchor Patellar Fixation for Medial Patellofemoral Ligament Reconstruction: A Cohort Study With 2-Year Follow-up.

Background:Several surgical methods have been developed for medial patellofemoral ligament reconstruction (MPFLR). However, the question of which patellar fixation method, suture anchor (SA) or transosseous tunnel (TO) fixation, achieves better overall outcomes remains to be answered.Hypothesis:SA patellar fixation will present comparable clinical outcomes and a lower complication rate compared with TO patellar fixation for MPFLR.Study Design:Cohort study; Level of evidence, 3.Methods:We retrospectively reviewed the outcomes of 46 patients who underwent MPFLR with either TO fixation (n = 21; mean age, 24.4 ± 6.1 years) or SA fixation (n = 25; mean age, 24.1 ± 12.1 years) for the treatment of recurrent patellar dislocation. Clinical findings (International Knee Documentation Committee [IKDC] subjective score, Lysholm score, and Tegner activity score), radiological findings (congruence angle and patellar tilt angle), and complications (redislocation, patellar fracture, patellofemoral osteoarthritis progression, infection, and stiffness) were compared between the TO and SA groups at the 2-year follow-up visit.Results:The mean postoperative IKDC subjective and Lysholm scores did not differ significantly between groups. However, postoperative Tegner activity scores were significantly higher in the TO group than in the SA group (TO, 5.8 ± 1.4; SA, 4.9 ± 1.2; P = .012). Congruence angle did not differ significantly between the groups (TO, −3.2 ± 22.8; SA, −7.6 ± 17.8; P = .464). Patellar tilt angle was lower in the TO group than in the SA group (TO, 10.5 ± 5.4; SA, 13.7 ± 2.8; P = .015). During the follow-up period, the TO group had 1 redislocation and 2 patellar fractures, whereas the SA group had no redislocations or fractures. Patellofemoral osteoarthritis progression was significantly higher in the TO group than in the SA group at the 2-year follow-up visit (TO, 9/21; SA, 2/25; P = .006).Conclusion:Both TO and SA patellar fixation methods for MPFLR showed improved clinical outcomes. When compared with TO fixation, SA fixation presented comparable clinical outcomes and a lower complication rate.

Long-term clinical results of the crosse de hockey procedure for recurrent patellar dislocation.

A gold standard procedure has not been established for recurrent patellar dislocation because of multifactorial etiologies. We have been performing crosse de hockey procedure, which is a combination of medial and anterior transfer of the tibial tuberosity, in our institution since 1993. This study aimed to investigate the long-term clinical results of this procedure. A total of 19 patients (21 knees) underwent the crosse de hockey procedure for recurrent patellar dislocation. Of these patients, four were lost to follow-up. The remaining 17 knees in 15 patients (5 male and 10 female) were included in this study. The mean follow-up period was 13.2 years (range: 5-22.6 years). Clinical evaluation was performed using the Kujala score. Radiographic indicators, such as modified Insall-Salvati ratio, sulcus angle, congruence angle, tilting angle, lateral shift ratio, and the progression of patellofemoral osteoarthritis (OA), were measured. Positive apprehension sign and redislocation were not observed in any of the patients. The mean Kujala score was significantly improved from 36.5 ± 18.0 preoperatively to 92.6 ± 9.9 at the final follow-up. Definite OA (a grade 2 or more using the Iwano grading system) was not observed in the patellofemoral joint at the final follow-up. The crosse de hockey procedure showed satisfactory long-term clinical results for recurrent patellar dislocation. This procedure could prevent the progression of patellofemoral OA because of the unloading effect of the patellofemoral joint by anteromedial transfer of the tibial tuberosity.

Hyperintense signal alteration in the suprapatellar fat pad on MRI is associated with degeneration of the patellofemoral joint over 48months: data from the Osteoarthritis Initiative.

To analyze associations of suprapatellar fat pad (SPFP) hyperintense signal alterations and mass effect with progression of patellofemoral osteoarthritis (OA) and clinical symptoms over 48months. Subjects from the Osteoarthritis Initiative (n=426; 51.8±3.8years; 49.8% women) without radiographic tibiofemoral OA underwent 3T-MRI of their right knees and clinical evaluation using the Knee Injury and Osteoarthritis Outcome Score at baseline and at 48months. Elevated SPFP signal was assessed on intermediate-weighted, fat-saturated turbo spin-echo (TSE) images. Mass effect was defined as a convex posterior contour. Patellofemoral cartilage, bone marrow lesions (BML), and subchondral cysts were assessed using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Associations of SPFP imaging findings with MRI and clinical progression were assessed using general linear models and logistic regressions. Baseline SPFP signal alterations were found in 51% of the subjects (n=217), of whom 11% (n=23) additionally had a mass effect. Progression of cartilage lesions was significantly higher in subjects with signal alteration versus without (adjusted mean increases, 95% CI; patella: 0.29, -0.07 to 0.64 vs -0.04, -0.40 to 0.31; p<0.001; trochlea: 0.47, 0.16 to 0.77 vs 0.31, 0.01 to 0.61; p=0.007). BML progression was also more likely in subjects with signal alteration (OR 1.75, 95% CI 1.09 to 2.82; p=0.021). Mass effect was not associated with joint degeneration and SPFP findings were not associated with clinical worsening (p>0.18 for all). Patellofemoral joint degeneration over 48months was significantly increased in subjects with SPFP signal alteration, suggesting an association between SPFP abnormalities and the progression of patellofemoral OA.

Patellofemoral Osteoarthritis Progression and Alignment Changes after Open-Wedge High Tibial Osteotomy Do Not Affect Clinical Outcomes at Mid-term Follow-up

To evaluate the clinical and radiological outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess whether patellofemoral osteoarthritis (OA) progression and alignment changes after OWHTO affect clinical outcomes. Inclusion criteria were consecutive patients who underwent OWHTO from March 2005 to September 2013. Exclusion criteria were loss to follow-up within 2years and absence of second-look arthroscopy findings at the time of plate removal. The clinical parameters, including anterior knee pain while climbing stairs, Japanese Orthopedic Association score, and Oxford Knee Score, were evaluated. Radiological outcomes, including weight-bearing line ratio, modified Blackburne-Peel ratio, posterior tibial slope, tilting angle, lateral shift ratio, and patellofemoral OA (Kellgren-Lawrence grade), were evaluated preoperatively and at the final follow-up. Cartilage status (International Cartilage Repair Society grade) was evaluated at the initial HTO and at plate removal. Fifty-three patients (60 knees) were included in this study. The mean follow-up was 58.2 ± 22.4months. Two knees (3%) presented with mild anterior knee pain after OWHTO. The mean Japanese Orthopedic Association score (66.9 ± 11.2 to 91.2 ± 9.7) significantly improved (P < .001), and the mean Oxford Knee Score at the final follow-up was 42.0 ± 5.3. The mean modified Blackburne-Peel ratio (0.9 ± 0.1 to 0.7 ± 0.1, P < .001) and tilting angle (6.8 ± 3.7 to 5.6 ± 3.4, P= .033) significantly decreased after OWHTO, whereas no significant changes in posterior tibial slope (P= .511) and lateral shift ratio (P= .522) were observed. Radiologically, patellofemoral OA had progressed in 15 knees (27%), and arthroscopically patellofemoral cartilage degeneration had progressed in 27 knees (45%). However, there was no significant correlation between changes in patellofemoral alignment and clinical outcomes. Changes in patellofemoral alignment and patellofemoral OA progression did not affect the clinical outcomes of OWHTO at mid-term follow-up. Level IV, therapeutic case series.

Oxidized zirconium versus cobalt–chromium against the native patella in total knee arthroplasty: Patellofemoral outcomes

BackgroundOxidized zirconium (OxZr) has demonstrated excellent mechanical properties in vitro when used against articular cartilage; less coefficient of friction and less chondral damage have been found when compared with cobalt–chromium (CoCr) implants. However, controversy exists as to whether implants with a zirconium femoral component articulate safely with a native patella in total knee arthroplasty (TKA). To answer this question, the clinical and radiographic results were analysed from a group of patients who underwent a TKA with patella retention; the OxZr versus CoCr femoral components were compared. MethodsThe present study prospectively evaluated 83 knees of 74 patients from 2009 to 2010. Each patient was evaluated clinically (visual analogue scale, Knee Society score, patellar score) and radiographically (long leg standing radiograph, anterior–posterior and latero-lateral projections, axial view of the patella) pre-operatively and postoperatively with a mean follow-up of 4.47years. The patellar tilt and shift, and progression of patellofemoral osteoarthritis were calculated with the axial view. ResultsThere were no patient reported adverse reactions and none of the evaluated prostheses failed. Both the clinical and radiographic evaluations showed no statistically significant between-group differences. ConclusionNo adverse events were observed clinically or radiologically. These results justify pursuing the use of oxidized zirconium as an alternative bearing surface for a femoral component associated with patellar retention in TKA.

Is Tibiofemoral or Patellofemoral Alignment or Trochlear Morphology Associated With Patellofemoral Osteoarthritis? A Systematic Review.

We conducted a systematic review to evaluate the associations of knee alignment or trochlear morphology (measured on imaging) with presence, severity, onset, and/or progression of patellofemoral osteoarthritis (PFOA). We prospectively registered our protocol with PROSPERO (International prospective register of systematic reviews) and followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to report this review. We searched 10 electronic databases, screened citing articles, and reviewed reference lists. We extracted data and evaluated methodologic quality. Due to study design heterogeneity, we used a best-evidence synthesis to summarize the evidence. We included 16 publications (2,892 participants, 66% women) after removing 4 papers that did not meet our threshold for methodologic quality. There were 11 cross-sectional and 5 longitudinal papers. The target population was knee OA in 11 studies, PFOA in 2 studies, and other knee conditions in 3 studies. Alignment or morphology was measured using radiographs in 8 studies, magnetic resonance imaging in 7 studies, and computed tomography in 2 papers. Limitations include substantial heterogeneity in samples and methods, short followup times in longitudinal studies, and a small number of studies that specifically recruited participants with PFOA. There is strong evidence that PFOA is associated with both trochlear morphology and frontal plane knee alignment, while evidence is limited but consistent in the sagittal and axial planes. These findings suggest that alignment should be evaluated clinically in individuals with PFOA. Clinical interventions targeting knee alignment warrant further investigation.

Clinical value of SPECT/CT in the painful total knee arthroplasty (TKA): a prospective study in a consecutive series of 100 TKA.

Bone single photon emission computed tomography (SPECT)/CT is considered as beneficial in unhappy patients with pain, stiffness or swelling after total knee arthroplasty (TKA). The purpose of this study was to identify typical patterns of bone tracer uptake (BTU), distribution and intensity values in patients after TKA. The above findings were correlated with the type and fixation of TKA, the time from TKA and intraoperative findings at revision surgery. A total of 100 knees of 84 consecutive patients (mean age ± SD 70 ± 11 years) after TKA with persistent knee pain were prospectively included. All patients underwent clinical examination, standardized radiographs and (99m)Tc-hydroxymethane diphosphonate (HDP) SPECT/CT as part of a routine diagnostic algorithm. The diagnosis before and after SPECT/CT and final treatment were recorded. TKA component position was determined on 3-D reconstructed images. Intensity and anatomical distribution of BTU was determined. Maximum intensity values were recorded as well as ratios in relation to the proximal midshaft of the femur. Univariate analyses (chi-square test, Pearson's correlation and t test for independent samples) were performed (p < 0.05). SPECT/CT changed the clinical diagnosis and final treatment in 85/100 (85 %) knees. Intraoperative findings confirmed the preoperative SPECT/CT diagnosis in 32/33 knees (97 %). TKA loosening as well as progression of patellofemoral osteoarthritis (OA) was correctly diagnosed in 100 % of knees. Typical patterns of BTU for specific pathologies were identified. Loose femoral TKA components significantly correlated with increased BTU at the lateral femoral regions (p < 0.05). Loose tibial TKA components significantly correlated with increased BTU at all tibial regions (p < 0.05) and around the tibial peg (p > 0.01). The diagnostic benefits of SPECT/CT in patients after TKA have been proven. Typical pathology-related BTU patterns were identified, which will improve reporting quality. Due to the benefits in establishing the correct diagnosis, SPECT/CT should be part of the routine diagnostic algorithm for patients with pain after TKA.

Deepening Trochleoplasty in Patellar Dislocation: Thick-Flap Technique

Deepening trochleoplasty is a technically demanding operation that is rarely required for most of the patients presenting with recurrent dislocation of the patella. However, in the presence of significant trochlear dysplasia, standard extensor mechanism realignment techniques can fail. A deepening trochleoplasty using a thick osteochondral flap technique is a logical solution for severe dysplasia and does not rely on the presence of normal articular cartilage in the trochlea. Satisfactory outcomes, including returning to sports for those who actively participate is usual. Theoretical complications such as chondrolysis and progression of patellofemoral osteoarthritis have not been found. This article describes the step-by-step operative technique with illustrations.

No difference in anterior knee pain after medial unicompartmental knee arthroplasty in patients with or without patellofemoral osteoarthritis.

The purpose of the present study was to compare functional outcomes of medial unicompartmental knee arthroplasty (UKA) in patients with patellofemoral osteoarthritis (PF OA) and those without PF OA and to evaluate the effect of PF OA on functional outcomes after UKA. The outcomes of 48 knees in patients without PF OA who underwent medial UKA (non-PF OA group) were compared to the outcomes of 57 knees in patients with PF OA [Kellgren-Lawrence (K-L) grade ≤ 2] who underwent medial UKA (PF OA group) with a median follow-up of 5.4 years (range 3.1-10.2 years). Clinical outcomes including anterior knee pain, HSS scores, radiological parameters, and the progression of patellofemoral osteoarthritis were compared, and their effects on functional outcomes were evaluated at the final follow-up visits. At final follow-up visits, no significant inter-group difference was found in terms of anterior knee pain (1.9 vs. 1.9 in non-PF OA and PF OA groups, respectively), HSS score, or range of motion. Preoperative anterior knee pain and patellofemoral joint degeneration were found to be unrelated to poor outcome in patients that underwent medial UKA. Furthermore, no correlation was found between any functional outcome variable and chondral lesion pattern. The result of UKA for medial unicompartmental knee osteoarthritis was excellent regardless of PF OA (K-L grade ≤ 2). Hence, the patients with medial unicompartmental OA combined with a moderate degree of anterior knee pain or patellofemoral arthritis should be viewed as appropriate candidates for medial UKA. III.

Asymptomatic obese subjects with MR-based indications of knee OA have altered gait kinetics

Asymptomatic obese subjects with MR-based indications of knee OA have altered gait kinetics