Patellofemoral Osteoarthritis Research Articles

Nonanatomical femoral tunnel positioning in isolated MPFL reconstruction is not associated with an increased risk of patellofemoral osteoarthritis after a minimum follow-up of 10 years.

The association between the prevalence of patellofemoral arthritis (PFA) and femoral tunnel positioning following isolated medial patellofemoral ligament reconstruction (MPFLr) has not been well described. The aim of this study was to analyse the relationship between femoral tunnel positioning and the prevalence of PFA. This was a single-centre study of patients undergoing an isolated MPFLr between 2006 and 2011 with a minimum of 10 years of follow-up. Outcomes assessed were the presence of PFA on radiographs, recurrence of instability requiring revision surgery and patient-reported outcomes, including Kujala, Tegner and IKDC scores. Tunnel positioning was assessed on postoperative radiographs using two radiographic methods: Schöttle's point and the grid method to localise the femoral tunnel. Patients were grouped based on tunnel positioning and compared. Fifty patients were analysed at a mean follow-up of 12.4 years. Thirty-three patients (66%) had a femoral tunnel position within 7 mm of Schöttle's point and 39 (78%) within the anatomic quadrant, with the most common location according to the grid method in D4 (28%) and E4 (26%), respectively. Thirty-seven patients (74%) had a satisfactory (>80 versus <80) Kujala score at long-term follow-up. None of the examined tunnel assessment methods demonstrated a significant relationship with Tegner, Kujala or International Knee Documentation Committee scores. Patients with a femoral tunnel position >7 mm outside Schöttle's pointor were considered to be in a nonanatomic position were not significantly more likely to result in unsatisfactory Kujala scores at the last follow-up. Tunnel positioning and the other tested parameters were not found to be significantly associated with the development of PFA. No correlation between femoral tunnel position and risk of PFA or poor outcomes was observed in patients undergoing isolated MPFLr at long-term follow-up. The impact of femoral tunnel placement on long-term outcomes in patients with PFI may be less significant than originally considered. Level IV.

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 quadriceps fat pad edema and patellofemoral osteoarthritis: a quantitative Q-Dixon-based magnetic resonance imaging (MRI) analysis.

Anterior knee pain (AKP) is a common symptom of patellofemoral osteoarthritis (PFOA). There is limited prospective evidence supporting the relationships between patellofemoral maltracking parameters, AKP, and PFOA. Thus, this prospective cross-sectional study aimed to determine the association between quadriceps fat pad (QFP) edema and patellofemoral maltracking in patients with chronic AKP and to evaluate the feasibility and diagnostic performance of a PFOA assessment using fat fraction (FF) and T2* based on Q-Dixon. This was a cross-sectional study with prospective data collection. Patients with chronic AKP were recruited from an orthopedic outpatient magnetic resonance imaging (MRI) waiting room at Shanghai Tongren Hospital between November 1, 2022, and April, 30, 2023. Exclusion criteria included age of <18 years, knee trauma, major internal derangement, prior surgery/arthroscopy, pre-existing joint diseases, and contraindications to MRI. MRI was performed using a 3.0-T instrument, and patellofemoral maltracking parameters were measured. Patellofemoral feature-relevant items, including patellar cartilage defects, patellar bone marrow lesions (BMLs), patellar osteophytes, anterior femoral osteophytes, Hoffa synovitis, and synovitis-effusion, from the semi-quantitative MRI Osteoarthritis Knee Score (MOAKS) were measured. The Anterior Knee Pain Scale (AKPS) was used to assess pain and function. FF/T2* measurement differences between groups and their associations with maltracking metrics, osteoarthritis grading based on the Iwano grading system, MOAKS, and AKPS, were investigated. Based on Iwano grading, the participants were categorized as having no-PFOA (n=40), mild PFOA (n=40), and advanced PFOA (n=40). Chi-squared and one-way analysis of variance were used to assess potential differences between the groups. Spearman's correlation test was used to analyze the correlation between the morphological parameters, AKPS, Iwano grade, MOAKS, and MRI quantitative values. Receiver operating characteristic (ROC) curves assessed the area under the curve (AUC), sensitivity, and specificity of quantitative values for distinguishing PFOA from no-PFOA. Among the 120 included patients, those in the mild (86.2±8.5) and advanced (83.9±9.5) PFOA groups had significantly lower AKPS scores than those in the no-PFOA group (88.8±7.3) (P=0.03). The mean FF and T2* values of the QFP were significantly higher in the no-PFOA group than those in the mild and advanced PFOA groups (P<0.001 for FF and P=0.02 for T2*). Quantitative data on the QFP and patellofemoral maltracking parameters showed no association. FF (r=-0.686, P<0.001) and T2* (r=-0.314, P=0.008) showed a negative correlation with the Iwano grade. The AUCs for PFOA diagnosis were 0.906 [95% confidence interval (CI), 0.853-0.960] (FF) and 0.744 (95% CI, 0.657-0.831) (T2*). QFP FF and T2* were not associated with patellofemoral maltracking parameters but with increased PFOA in patients with AKP, suggesting that QFP abnormalities play a role in PFOA. Therefore, a quantitative QFP assessment (FF and T2*) based on Q-Dixon technology could be a convenient and reliable new imaging biomarker for PFOA severity during clinical diagnosis, treatment, and follow-up.

Patellofemoral osteoarthritis, should we replace or osteotomize?

Athletes are prone to patellofemoral arthritis, a multi-factorial condition including patellofemoral malalignment, instability, overuse, and trauma incurred across diverse sporting disciplines. Surgical options for treating this condition include extensor mechanism realignment osteotomy and patellofemoral arthroplasty. Each procedure carries distinct advantages and considerations. Selection of the most suitable approach requires a comprehensive understanding of the procedures and patient specific factors such as severity of cartilage defects, malalignment, and the patient's preferences, and activity goals. For early-stage patellofemoral osteoarthritis, particularly in cases involving malalignment, tibial tubercle osteotomy can be an effective treatment, while arthroplasty becomes more valuable in more advanced and progressive cases. This chapter aims to establish a clear algorithmic approach for the utilization of realigning tibial tubercle osteotomy and patellofemoral arthroplasty in the management of patellofemoral osteoarthritis.

Is muscle activation diverse in females with isolated patellofemoral osteoarthritis contrasted with age-matched healthy controls during stair descent task?

Background: Patellofemoral osteoarthritis (PF OA) is exceptionally predominant and limiting. However, little is known about the risk factors that contribute to its onset and progression. Purpose: The aim of this study was to decide if women with PF OA descend stairs using different muscular activation strategies compared to similarly aged healthy controls. Methods: Thirty-one women with isolated PF OA and 11 similarly aged healthy women took part in this study. The activation onset and duration of PF OA in vastus medialis oblique (VMO), vastus lateralis (VL), gluteus medius (GM), transversus abdominis (TrA), and multifidus muscles were evaluated during the stair descent task using surface electromyography (EMG). Results: There was a non-significant difference between women with PF OA and healthy controls regarding all tested variables, except for the GM activation onset that was significantly delayed in women with PF OA, with the p-value of 0.011. Conclusion: The causes of PF OA differ and might not always be due to a lack of quadriceps strength or VMO activation deficiency, and prospective longitudinal studies are required to confirm this assumption.

Associated patellofemoral osteoarthritis is not a contraindication for unicompartmental knee replacement. Report of one hundred ten prostheses with an average 6-year follow-up

IntroductionAssociated patellofemoral joint osteoarthritis (APFJ-OA) has typically been considered a contraindication for unicompartmental knee arthroplasty (UKA) in the treatment of femorotibial joint osteoarthritis. However, this contraindication is being challenged. The aim of this study was to assess clinical and functional outcomes, complications, and implant survival in medial or lateral UKA, regardless of clinical symptoms or radiographic signs of APFJ-OA. MethodsThis retrospective, comparative study included patients treated with medial or lateral UKA regardless of preoperative symptoms or signs of APFJ-OA, with a minimum 2-year follow-up. Intraoperatively, knees were subdivided based on APFJ-OA grade, according to the Outerbridge classification. Clinical and functional outcomes were analyzed using the 2011 Knee Society Score (KSS) at the last follow-up control. APFJ-OA was treated systematically, in a tailored, stepwise fashion according to its severity. Complications and implant survival rates were evaluated. Two-sided paired T-test, ANOVA, and Kruskal–Wallis tests were used with a significance level of 5%. ResultsFinally, 110 UKAs were assessed 81 (73.6%) medial and 29 (26.4%) laterals. The average follow-up was 6 years (2–19.5). According to Outerbridge, 22 knees (20%) were in grade 2, 59 (53.6%) were in grade 3, and 29 (26.4%) were in grade 4. All three groups showed a statistically significant increase in KSS scores and range of motion. There were no significant differences in clinical KSS improvement and flexion contracture between Outerbridge groups (average 35.7 and −4.9, respectively). Group 3 showed statistically significant improvement in functional KSS when compared to group 2 (68.8 vs 61.2). In maximum flexion, groups 3 and 4 did significantly better than group 2 (20° vs 15°). Three prostheses (2.7%) needed revision after 7, 8.6, and 12 years due to aseptic tibial loosening. Implant survival was 100% at 5 (64 of 64), 97% at 7 (30 of 31), 93% at 9 (14 of 15), and 89% at 12 years, respectively (8 of 9). ConclusionClinical and functional results, complications, and survival of medial or lateral UKA were not negatively affected by APFJ-OA assessed intraoperatively using the Outerbridge classification after an average follow-up of 6 years. We consider that APFJ-OA is not a contraindication for UKA when treated systematically according to its severity. Level of evidenceIV.

Almost 79% survival rate at 10-year follow-up for the patellofemoral joint arthroplasty: An Italian prosthetic registry study.

The aims of the present study were (1) to evaluate the survival of patellofemoral joint (PFJ) arthroplasty in a large cohort of patients using data obtained from an Italian regional arthroplasty registry and (2) to collect clinical outcomes of a subgroup of patients, with a minimum follow-up of 4 years. The hypotheses were that PFJ arthroplasty is a procedure that had good survival and clinical outcomes, not inferior to those reported in the literature for primary total knee arthroplasty (TKA). The Register of Orthopaedic Prosthetic Implants (RIPO) of Emilia-Romagna (ER) (Italy) database was searched for the inclusion of all PFJ arthroplasties implanted between 2003 and 2019. PFJ arthroplasties were excluded if they were implanted in patients who lived outside of the ER. The survival information was extrapolated from the RIPO considering the partial or total revision of the implant as failure; moreover, a subgroup of patients was contacted and interviewed by telephone to collect clinical outcomes. Descriptive statistics were used to summarise the data. The survival curve was calculated and plotted using the Kaplan-Meier method. A total of 126 arthroplasties in 114 patients were included in the final analysis (mean age at surgery 60.1 ± 11.5 years old). The main causes of patellofemoral arthroplasty were primary osteoarthritis (88%) and posttraumatic arthritis (7%). The survival was 90.4 ± 30.6 and 78.8 ± 51.5 at 5 and 10 years of follow-up, respectively. At the latest follow-up, 23 implants failed (18.3%). The main cause of revision was osteoarthrosis progression (34.8%). A total of 44 patients were contacted by telephone to collect clinical outcomes: Western Ontario and McMaster Universities Osteoarthritis Index, functional Knee Society Score, Forgotten Joint Scoreand Oxford Knee Score. These patients reported good to excellent scores at a medium follow-up of 10.3 ± 4.7 years. The PFJ showed good survival and clinical outcomes and could be considered a valuable option for patients affected by isolated patellofemoral osteoarthritis. Level IV.

Clinical outcomes of patellofemoral arthroplasty: robotic assistance produces superior short and mid-term outcomes.

Patellofemoral arthroplasty (PFA) has been shown to provide symptomatic improvement for isolated patellofemoral osteoarthritis (PFOA). The efficacy of robotic-assisted PFA and the most suitable PFA implant design, however, remain ongoing matters of debate. This study sought to compare clinical outcomes between patients who underwent robotic-assisted versus conventional PFAs with inlay and onlay prosthetic designs. A single-center retrospective review found 237 knees (211 patients) which underwent PFA between 2011 and 2021. One hundred eighty-four knees were included in the final analysis after cases were excluded for having indications other than osteoarthritis or having less than one year of follow-up. There were 90 conventional PFAs and 94 robotic-assisted PFAs performed. Inlay components were implanted in 89 knees and onlay components were implanted in 95 knees. Propensity score matching was utilized to address demographic differences between groups. Overall, there was a revision-free survivorship rate of 89.7% with an average time to follow-up of 4.6years (range 1.2 to 11.1). Twenty-nine knees (15.8%) required various non-conversion procedures. The conventional matched cohort exhibited a higher all-cause revision rate, accounting for revision PFAs and conversions to TKA, (18.8 vs. 6.4%, p = 0.014) and a shorter mean time to revision than the robotic-assisted cohort (3.1 vs. 5.8years, p = 0.026). A Kaplan-Meier survivorship curve showeddifferences between the conventional and robotics cohorts (p = 0.041). All revisions following robotic-assisted PFA were caused by progression of osteoarthritis, whereas conventional PFAs also required revision due to aseptic loosening and patellar maltracking. The rate of infection resulting in irrigation and debridement was higher for conventional cases (4.3 vs. 0%, p = 0.041). No significant differences in clinical outcomes between the inlay and onlay prosthetic design matched cohorts were identified. PFA is an effective treatment for addressing advanced patellofemoral arthritis. Robotic-assisted surgery may lead to improved clinical outcomes. III.

Three-dimensional kinematics of the trunk, pelvis, hip, and knee during the single-leg squat and hip torque in subjects with isolated patellofemoral osteoarthritis compared to individually matched controls: Preliminary results.

Objectives: This study aimed to compare three-dimensional kinematic of the trunk, pelvis, hip, and knee during the single-leg squat and hip torque in individuals with and without isolated patellofemoral osteoarthritis (PFOA). Patients and methods: This cross-sectional study evaluated trunk, pelvis, hip, and knee kinematics at 30°, 45°, and 60° knee flexion during the single-leg squat using the Vicon motion capture and analysis system, the Nexus System 2.1.1, and 3D Motion Monitor software. Sixteen individuals (8 males, 8 females; mean age: 49.3±6.2 years; range 40 to 61 years) participated in the study, of which eight were PFOA patients and eight were healthy controls. Isometric hip abductor, extensor, and external rotator torques were evaluated using a handheld dynamometer. Results: The PFOA group exhibited greater hip adduction at 30° (p=0.008), 45° (p=0.005), and 60° (p=0.008) knee flexion in the descending phase of the single-leg squat, as well as at 60° (p=0.009) and 45° (p=0.03) knee flexion in the ascending phase. No significant differences were found between groups for other kinematic variables (p>0.05). The PFOA group exhibited lower isometric hip abductor (p=0.02), extensor (p <0.001), and external rotator (p=0.007) torques. Conclusion: Individuals with PFOA exhibited excessive hip adduction that could increase stress on the lateral patellofemoral joint at 30°, 45°, and 60° knee flexion during the single-leg squat and exhibited weakness of the hip abductors, extensors, and external rotators in comparison to healthy controls.

Patella Fractures outcome after Tension Band Wiring; a Cross-sectional Study

Objective: The most common technique for fixing patella fractures is tension band wiring (TBW). The current study aimed to assess the functional and radiological outcomes of the patellar fractures treated by TBW. Patients and Methods: This retrospective cohort study was performed on 78 patients who underwent TBW of patellar fracture in Akhtar Orthopedic Hospital, Tehran, Iran, from September 2015 to April 2018 and had completed a two-year follow-up. A surgical intervention consisting of open reduction and internal fixation was performed on all patients using TBW. Patients were evaluated two years postoperatively by clinical examination, radiographic investigation, and three scales (Tegner activity score [TAS], Lysholm knee score [LKS], and lower extremity functional scale [LEFS]). Result: Of the 78 patients, 48 (61.5%) were male, with a mean age of 36.7 13.1 years. Postoperatively, 41 (52.6%) patients had anterior knee pain, and four (5%) patients had an infection. Knee range of motion was limited in 20 (25.6%) patients. The mean postoperative TAS, LKS, and LEFS mean scores were 4.3 1.34, 85.97 9.21, and 69.62 6.68, respectively. Age was inversely correlated with LKS and LEFS, as both scores decreased with increasing age (p 0.001, r:-0.4). Younger patients (under 30 years old) were more likely to reach their pre-injury TAS score than older patients (p 0.001). In addition, patellofemoral osteoarthritis and patella baja were significantly higher in patients with comminuted fractures than in those with simple fracture patterns (p 0.001). Conclusion: We found acceptable outcomes after fixation with TBW, especially in younger patients; LKS and LEFS scores were lower in the elderly, and younger patients were more likely to reach closer to their pre-injury TAS score. Furthermore, patellofemoral osteoarthritis and patella baja were associated with comminuted patella fractures.

Radiomics analysis of patellofemoral joint improves knee replacement risk prediction: Data from the Multicenter Osteoarthritis Study (MOST)

ObjectiveKnee replacement (KR) is the last-resort treatment for knee osteoarthritis. Although radiographic evidence of tibiofemoral joint has been widely adopted for prognostication, patellofemoral joint has gained little attention and may hold additional value for further improvements. We aimed to quantitatively analyse patellofemoral joint through radiomics analysis of lateral view radiographs for improved KR risk prediction. DesignFrom the Multicenter Osteoarthritis Study dataset, we retrospectively retrieved the initial-visit lateral left knee radiographs of 2943 patients aged 50 to 79. They were split into training and test cohorts at a 2:1 ratio. A comprehensive set of radiomic features were extracted within the best-performing subregion of patellofemoral joint and combined into a radiomics score (RadScore). A KR risk score, derived from Kellgren-Lawrence grade (KLG) of tibiofemoral joint and RadScore of patellofemoral joint, was developed by multivariate Cox regression and assessed using time-dependent area under receiver operating characteristic curve (AUC). ResultsWhile patellofemoral osteoarthritis (PFOA) was insignificant during multivariate analysis, RadScore was identified as an independent risk factor (multivariate Cox p-value < 0.001) for KR. The subgroup analysis revealed that RadScore was particularly effective in predicting rapid progressor (KR occurrence before 30 months) among early- (KLG < 2) and mid-stage (KLG ​= ​2) patients. Combining two joints radiographic information, the AUC reached 0.89/0.87 for predicting 60-month KR occurrence. ConclusionsThe RadScore of the patellofemoral joint on lateral radiographs emerges as an independent prognostic factor for improving KR prognosis prediction. The KR risk score could be instrumental in managing progressive knee osteoarthritis interventions.

Development of patellofemoral osteoarthritis with knee joint malalignment and lateral patellar dislocation after hindlimb suspension in growing rats.

Knee malalignment is a risk factor for patellar instability and patellofemoral osteoarthritis (PFOA), but etiologies remain unknown. We investigated the potential effects of decreased weight loading during growth on knee alignments and patellofemoral (PF) joint pathology. Hindlimb suspension (HS) was performed in 4-week-old female rats for 2, 4, and 8 weeks (HS groups). Age-matched rats were used as controls. Three-dimensional reconstructed images of the knee were obtained using X-ray computed tomography. Tibial tubercle-trochlear groove (TT-TG) distance, patellar tilt angle, and bisect offset were measured as indices of knee alignment. Histological analysis was also performed to evaluate the changes in cartilage and synovium in the PF joints. At Week 8, TT-TG distance, patella tilt angle, and bisect offset were significantly larger in the HS group than in the control group, respectively, indicating tibial external rotation, outward patellar tilt, and external displacement of the patella. Lateral patellar dislocation was frequently found in the HS group at Week 8 (five of eight knee joints, p < 0.05). Degenerative changes in the cartilage of the trochlear groove were observed at Week 8, and synovial changes such as hypertrophy and synovitis were observed at Weeks 4 and 8. Correlation analyses revealed significant relationships between the Mankin score and bisect offset, and between the OARSI synovitis score and all knee alignments indices. These results suggest that decreased weight loading on the lower extremities in growing rats resulted in knee malalignments characterized by external rotation of tibia and high incidence of lateral patellar dislocation with concomitant PFOA.

Clinical and Radiological Outcomes After Combined ACL and MPFL Reconstruction Versus Isolated ACL Reconstruction for ACL Injury With Patellar Instability

Background: An anterior cruciate ligament (ACL) injury accompanied by patellar instability (PI) is a topic that has gained orthopaedic surgeons’ attention recently. Untreated PI is reportedly associated with worse clinical outcomes after isolated ACL reconstruction (ACLR) in patients after an ACL injury with PI. Nevertheless, the appropriate surgical approach and its long-term therapeutic effects in these patients remain unclear. Purpose: (1) To compare the clinical and radiological outcomes between isolated ACLR (iACLR) and combined ACLR and medial patellofemoral ligament reconstruction (cAMR) in patients after an ACL injury with PI and (2) to explore the correlations between these 2 procedures and clinical and radiological outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 106 patients diagnosed with an ACL injury accompanied by PI between January 2016 and April 2021 were analyzed in this study. There were 34 patients excluded because of missing postoperative radiological data. Among the remaining 72 patients, 34 patients underwent iACLR, while 38 patients underwent cAMR. Demographic characteristics, intraoperative findings, and patient-reported outcomes (Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity score) were prospectively collected. Patellar alignment parameters and worsening patellofemoral osteoarthritis (PFOA) features (evaluated with the modified Whole-Organ Magnetic Resonance Imaging Score) were analyzed longitudinally on magnetic resonance imaging. The Kujala score was used to evaluate the functional recovery of the patellofemoral joint, and redislocations of the patella were prospectively recorded. Finally, multivariate logistic regression analysis was used to explore the correlations between these 2 procedures and clinical (not achieving the minimal detectable change [MDC] for the Lysholm score) and radiological (worsening PFOA features) outcomes. Results: The mean follow-up duration was 28.9 ± 6.2 and 27.1 ± 6.8 months for the iACLR and cAMR groups, respectively (P = .231). Significantly higher Lysholm scores (88.3 ± 9.9 vs 82.1 ± 11.1, respectively; P = .016) and subjective International Knee Documentation Committee scores (83.6 ± 11.9 vs 78.3 ± 10.2, respectively; P = .046) were detected in the cAMR group compared with the iACLR group postoperatively. The rates of return to preinjury sports were 20.6% and 44.7% in the iACLR and cAMR groups, respectively (difference, 24.1% [95% CI, 3.3%-45.0%]; P = .030). Moreover, the rates of worsening PFOA features were 44.1% and 18.4% in the iACLR and cAMR groups, respectively (difference, 25.7% [95% CI, 4.9%-46.4%]; P = .018). In addition, significantly higher Kujala scores (87.9 ± 11.3 vs 80.1 ± 12.0, respectively; P = .006), lower redislocation rates (0.0% vs 11.8%, respectively; difference, 11.8% [95% CI, 0.9%-22.6%]; P = .045), and significantly better patellar alignment were detected in the cAMR group compared with the iACLR group postoperatively. Furthermore, multivariate logistic regression analysis determined that iACLR and partial lateral meniscectomy were significantly correlated with not achieving the MDC for the Lysholm score and worsening PFOA features in our study population. Conclusion: In patients after an ACL injury with PI, cAMR yielded better clinical and radiological outcomes compared with iACLR, with better patellar stability and a lower proportion of worsening PFOA features. Furthermore, not achieving the MDC for the Lysholm score and worsening PFOA features were significantly correlated with iACLR and partial lateral meniscectomy. Our study suggests that cAMR may be a more appropriate procedure for patients after an ACL injury with PI, which warrants further high-level clinical evidence.

Isolated Patellofemoral Osteoarthritis

Isolated patellofemoral osteoarthritis is a complex pathology. It occurs frequently in women over 40 years and leads to a high degree of suffering. The causes of femoropatellar degeneration are manifold and require stage-specific therapy. This is very challenging for the treating physician. This article is intended to provide a structured overview of the symptoms, diagnostics and stage-specific therapy of patellofemoral osteoarthritis.

Outcomes >30 Years After Initial Nonoperative Treatment of Anterior Cruciate Ligament Injuries

Background: It is unclear how anterior cruciate ligament (ACL) reconstruction (ACLR) affects the development of osteoarthritis (OA). This uncertainty is partly caused by the lack of long-term studies on ACL injuries treated primarily without reconstruction and the underreporting of symptomatic OA. Purpose: To determine (1) the knee function, symptoms, and activity level, as well as the presence of radiographic and symptomatic OA; (2) how these clinical outcomes have changed over time; and (3) the frequency of subsequent knee surgeries after the index ACL injury in a cohort of patients with ACL injuries treated primarily without reconstruction. Study Design: Case series; Level of evidence, 4. Methods: A total of 100 patients underwent initial nonoperative treatment >30 years ago (mean, 33.2 ± 1.4 years). Of these, 81 patients (mean age, 59 ± 8 years) completed the Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm Knee Scoring Scale, and Tegner Activity Scale. Seventy-three patients underwent radiography to evaluate tibiofemoral and patellofemoral OA in the ACL-injured knee. Patients only underwent late ACLR if they experienced insufficient knee stability. Results: At 33 years after the ACL injury, the KOOS Activities of Daily Living subscore was better than population-based reference values, but scores were similar for the remaining KOOS subscales. Furthermore, 65% of patients had a good or excellent Lysholm score (≥84 points). The Tegner score decreased 4 points from before the injury to 33-year follow-up (P < .001). Most patients (75%) had evidence of radiographic tibiofemoral and/or patellofemoral OA, but only 38% were classified as having symptomatic OA (defined as radiographic OA in combination with a symptomatic knee according to cutoffs on the KOOS). Approximately 50% underwent meniscal surgery, and 29% subsequently underwent ACLR for recurrent instability. There were 2 patients who underwent total knee replacement. Conclusion: Despite a high prevalence of radiographic OA, patients achieved acceptable subjective knee function and had a relatively low prevalence of symptomatic OA at >30 years after an ACL injury when an initial nonoperative treatment strategy was employed.

MPFL reconstruction with proximal rather than distal femoral tunnel position leads to less favorable short-term results

BackgroundThis study aimed to compare the clinical and radiological outcomes of medial patellofemoral ligament (MPFL) reconstruction (MPFLR) between anatomic femoral tunnel positions: proximal (near adductor tubercle [AT]) and distal (near medial epicondyle [ME]). HypothesisMPFLR with the proximal femoral tunnel position has worse clinical and radiological outcomes than those with the distal femoral tunnel position. Patients and methodsFifty-five patients who underwent isolated MPFLR with proximal or distal femoral tunnels with at least 2 years of follow-up were retrospectively analyzed. Based on postoperative CT images, 28 patients were classified as group AT and the remaining 27 patients were classified as group ME. The International Knee Documentation Committee, Lysholm, Tegner, Kujala scores, and complications were evaluated. Radiologically, the Caton-Deschamps Index (CDI), patellar tilt angle, patellofemoral osteoarthritis (PFOA), patellofemoral cartilage status by the International Cartilage Repair Society (ICRS) grade, bone contusion, and MPFL graft signal intensity were evaluated. ResultsAll clinical scores significantly improved in both groups (p<0.01). No statistically significant difference was noted between the two groups in regards to their preoperative demographic data, postoperative clinical scores, complications, or radiological findings (CDI, patellar tilt angle, PFOA, bone contusion, and graft signal intensity). The group AT had worse cartilage status on the medial facet of the patella (p=0.02). The ICRS grade for the medial facet of the patella statistically progressed in group AT compared to group ME (p=0.04) as well. DiscussionBoth groups showed significantly improved clinical outcomes. However, for the medial facet of the patella, MPFLR with the proximal femoral tunnel position had worse cartilage status and ICRS grade progression than those with the distal femoral tunnel position. Level of evidenceIII; retrospective comparative study.

Patello-femoral arthroplasty- indications and contraindications

Patellofemoral arthroplasty (PFA) is emerging as an attractive alternative to total knee arthroplasty (TKA) for isolated patellofemoral-osteoarthritis (PF-OA) for selected patients. The success of PFA is highly dependent on patient selection. This intervention is still burdened with a higher rate of revisions and a lower survival rate than TKA when the indications or the surgical technique are not optimal. We highlight the indications and contraindications of PFA to obtain satisfying functional outcomes and survivorship. Preoperative clinical and radiological assessment is critical to determine the presence of PFA indications, the absence of contraindications and the necessity of any associated procedures, particularly for the tibial tubercle.The typical indications are patients with isolated symptomatic PF-OA, with trochlear dysplasia, when bone-on-bone Iwano 4 osteoarthritis is observed, without significant malalignment and with the absence of risk factors for developing progressive tibiofemoral-OA. The three main causes of isolated PF-OA are primary OA, trochlear dysplasia and posttraumatic OA following patellar fracture. Trochlear dysplasia is the preferred indication for PFA. Lack of experience with arthroplasty or realignment of the extensor mechanism is a relative contraindication to performing PFA.

Anatomical site of radiographic degeneration is an independent variable influencing outcome of total knee arthroplasty

ObjectivesWe aimed to determine whether the site of anatomical degenerative change could be identified as an independent risk factor influencing clinical outcome of total knee arthroplasty (TKA) 12 months postoperatively. MethodsWe compared preoperative, postoperative and the change observed in Oxford Knee Score (OKS) amongst TKA patients categorised as primarily medial, lateral or patellofemoral osteoarthritis (PFJOA). Multivariable regression analysis was conducted on 434 consecutive knees in 333 patients, adjusting for sex, age and body mass index (BMI). ResultsAdjusted estimates showed that preoperatively, patients with medial and lateral osteoarthritis (OA) had a lower mean OKS of 2.1 (p ​= ​0.049) and 2.3 (p ​= ​0.056) points respectively, while those with PFJOA had mean scores 2.7 points higher (p ​= ​0.062). There was no statistically significant difference between compartments in absolute postoperative OKS. The greatest improvement of 30.1 points (95% confidence interval (CI) 16.9–36.0, p ​= ​0.012) in OKS was observed for those with lateral OA, followed by 28.9 points (95% CI 16.7–35.3, p ​= ​0.049) for those with medial OA. The improvement observed postoperatively in patients with PFJOA was less than that observed for the average of the cohort at 24.5 (95% CI 11.5–29.7, p ​= ​0.088). ConclusionsThe site of compartmental involvement in knee OA is an independent factor influencing clinical outcome of TKA. With arthroplasty registry adoption of patient-reported outcome measures (PROMs), this study supports precise anatomical categorisation of knee OA in outcome studies. Level of EvidenceLevel III, Retrospective consecutive clinical study.

Trends in unicompartmental knee arthroplasty among 138 international experienced arthroplasty knee surgeons

PurposeUnicompartmental knee arthroplasty (UKA) is an established option for treating isolated unicompartmental knee osteoarthritis (OA), but controversies still exist about patient selection, indications, perioperative management and alignment goals. This survey was designed to understand the current trends of experienced arthroplasty knee surgeons performing UKA. MethodsAn online questionnaire was created with SurveyMonkey® to assess global tendencies in the utilization of UKA. A link to the survey was shared with all ESSKA (European Society for Sports Traumatology, Knee Surgery and Arthroscopy) members. The questionnaire consisted of free and multiple-choice questions and was divided into four sections: demographic information, the surgical activity of the respondents, indications for surgery and postoperative alignment goals. ResultsA total of 138 ESSKA members from 34 different countries completed the survey. A total of 81 % of the responders performed fewer than 50 UKAs per year; 53 % of UKAs represented less than 20 % of their knee replacements; 71 % used mainly or only fixed-bearing implants; 81 % performed UKA in a shorter time compared to TKA; and 61 % and 72 % were interested in custom-made UKA and robotics, respectively. Thirty-six percent considered a minimum postoperative alignment of 0° for medial UKA, and 32 % considered 10° as the maximum valgus deformity for lateral UKA. Fifty-five percent had no minimum age cut-off, 47 % had no BMI cut-off, and 57 % believed TKA was better than UKA in knees with concomitant high-grade patellofemoral OA. Approximately 50 % of the surgeons desired a coronal alignment that was the same as the predegeneration alignment. ConclusionA high level of agreement was reached regarding the following: preference for fixed-bearing UKAs, lower surgical time for UKA compared to TKA, interest in custom-made and robotic UKAs, no age and weight cut-off, TKA preferred in the presence of patellofemoral OA, and a final alignment goal of the predegenerative state both for medial and lateral. There was no agreement regarding length of stay, rehabilitation protocol, preoperative varus and valgus cut-off values, and treatment in cases of absence of anterior cruciate ligament or previous osteotomy.

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&lt;0.001 for all), and cases had a higher incidence of trochlear dysplasia (P&lt;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.