OBJECTIVE: This study aimed to: (i) understand how women perceived their recently developed patellofemoral pain (PFP) regarding its cause, prognosis, and willingness to seek treatment; (ii) investigate self-reported function, knee-related quality of life (QoL), fear of movement, and physical activity level at the onset of PFP.
METHODS: Mixed-methods longitudinal study.
METHODS: University.
METHODS: Sixty-eight pain-free women were followed up over one year.
METHODS: Those who developed PFP were interviewed within one month of the development of symptoms. Self-reported function, kinesiophobia, knee-related QoL, and physical activity were obtained at baseline and follow-up assessments.
RESULTS: Twenty-one women developed PFP. Most participants reported believing the increase in physical activity and/or sitting time was associated with the onset of PFP. Many reported believing symptoms would improve over time without any treatment. Only a small number of participants intended to seek care. Quantitatively, decreases in self-reported function and QoL, as well as increases in the physical activity level were observed after PFP development.
CONCLUSIONS: Although decreases in self-reported function and QoL were observed, women reported believing their PFP is self-limiting and do not need treatment. Strategies to accurately disseminate knowledge about PFP are needed to help stimulating early care.

OBJECTIVE: Donor site morbidity is the main drawback to using bone-patellar tendon-bone (BPTB) as a graft in anterior cruciate ligament (ACL) reconstruction. The objective of the study was to determine whether refilling the patellar bone defect after BPTB harvesting with autograft bone decreased kneeling pain to a greater degree when compared with a group in which bone defect is left unaddressed.
METHODS: This is a randomised single-blinded controlled study. Forty patients were randomised into two groups; group 1: Patellar bone defect filled with autologous bone; group 2: Bone defect left undressed. Pain was measured by means of pressure algometry (PA). Functional outcomes were measured with the Kujala and Victorian Institute of Sport Assessment-Patella (VISA-P) score. Magnetic resonance imaging (MRI) was done to measure bone buildup between groups at the 1-year follow-up.
RESULTS: No differences were observed in the different algometry measurements and the scores were assessed at 3, 6 and 12 months postoperatively. The ratio of void filled remained consistently higher (p = 0.003) in group 1 when compared to group 2.
CONCLUSIONS: Although refilling the lower pole of the patella with autologous bone from the harvested BPTB autograft loads the bone defect, it does not reduce pain at the donor site 1 year after surgery.
METHODS: Therapeutic study level 1.

BACKGROUND: International rates of patellar resurfacing in primary total knee arthroplasty (TKA) are highly variable. This study sought to determine how trends in patellar resurfacing rates have changed between 2004 and 2022. In addition, we investigated how modern rates of revision have varied between resurfaced and un-resurfaced patellae in primary TKA among national joint registries.
METHODS: Data between 2004 and 2022 was obtained either from the publicly available joint registry annual reports, a literature review, or via direct correspondence with registry personnel in Sweden, New Zealand, Australia, the United States, Norway, the United Kingdom, the Netherlands, Switzerland, Canada, and India. Only English-language national joint registries or data via direct correspondence with registry administrators were utilized. Additionally, the 10-year cumulative risk of revision TKA with and without patellar resurfacing was pulled from those registries that had this data available.
RESULTS: There were persistent differences in the rates of patellar resurfacing among countries. Australia documented a 40% increase in patellar resurfacing rates, while other countries demonstrated modest or little change in resurfacing rates. This may indicate that surgeons are making the decision to resurface based on national TKA revision rates. The average rates of patellar resurfacing in primary TKA ranged from 4% in Sweden to 94% in the United States. Canada, the United States, Australia, and Switzerland documented a lower risk of revision when the patella was resurfaced, while Sweden, conversely, showed a higher risk of revision with resurfacing.
CONCLUSIONS: Rates of patellar resurfacing in primary TKA were highly variable among countries, as were rates of change over time. It appears that the optimal patellar resurfacing strategy may depend mostly on unique patient factors and surgeon expertise. Future studies should attempt to elucidate the individual patient characteristics that contribute to increased risks of revision or anterior knee pain to determine who will most benefit from patellar resurfacing in primary TKA.

BACKGROUND: Anterior knee pain (AKP) is a common complaint following intramedullary nail (IMN) insertion for tibial shaft fractures. There is a lack of long-term patient reported outcome data following tibial IMN, with conflicting evidence of the role of nail protrusion on AKP. In this study, we assess the long-term patient reported outcome measures and kneeling function in patients with tibial IMNs and compare the results with IMN protrusion, measured radiologically.
METHODS: A retrospective cohort of 128 patients, from a single UK centre, were invited to participate in the study, to complete a Kujala score, KOOS, EQ-5D-5L and a four-posture kneeling assessment. We report the outcomes of 45 patients at an average follow-up of 6.9 years.
RESULTS: The mean Kujala score was 80.7. The mean KOOS score was 83.2, 83.9, 85.8, 70.7 and 72.8 for symptoms, pain, daily living, sport and quality of life, respectively. We found 20.5% of patients experienced daily AKP. Pain and fear of pain were the most common limiting factors in the kneeling assessment. No significant correlation was found between the KOOS or Kujala score and nail-plateau distance, nail-anterior cortex distance, or the overall nail prominence.
CONCLUSIONS: AKP affects a subset of patients more than five years post-tibial IMN, limiting their ability to kneel and other functions of daily living. Tibial IMN prominence does not seem to be associated with AKP.

UNASSIGNED: Pain and symptoms of patellofemoral pain (PFP) are often exacerbated during daily activities, which may result in reduced overall physical activity levels.
UNASSIGNED: To summarize the evidence for physical activity levels among persons with PFP compared with pain-free controls.
UNASSIGNED: PubMed, Embase, CINHAL, Cochrane Library, and SPORTDiscus were searched from January 1, 2000 to February 22, 2024.
UNASSIGNED: Peer-reviewed studies published in English that measured physical activity subjectively or objectively in persons with PFP and pain-free controls.
UNASSIGNED: Systematic review with meta-analysis.
UNASSIGNED: Level 1.
UNASSIGNED: Standardized mean difference (SMD) with 95% CI are reported based on Hedges\' g effect sizes.
UNASSIGNED: From 23,745 records, 41 studies met the eligibility criteria. There was high-to-moderate-certainty evidence that persons with PFP reported higher physical activity levels compared with pain-free controls using the International Physical Activity Questionnaire (SMD, 0.27; 95% CI 0.03, 0.51), whereas lower physical activity levels compared with pain-free controls using the Tegner Activity Scale (SMD, -0.31; 95% CI -0.57, -0.04). There was low-to-moderate-certainty evidence that there was no group difference in physical activity levels using the Baecke Physical Activity Questionnaire (SMD, 0.17; 95% CI -0.09, 0.44) or self-reported sports participation duration (SMD, -0.46; 95% CI -0.98, 0.05). There was high-certainty evidence that runners with PFP reported shorter running distances compared with pain-free runners (SMD, -0.36, 95% CI -0.57, -0.14). No data pooling was possible for objectively measured physical activity levels due to device heterogeneity (ie, different algorithms used to quantify the intensity of physical activity).
UNASSIGNED: Self-reported physical activity levels among persons with PFP were inconsistent depending on the physical activity measurement tool used or which specific physical activity was measured. Clinicians should integrate multiple physical activity assessment tools to determine the extent to which PFP influences physical activity levels.
UNASSIGNED: PROSPERO #CRD42022314598.

OBJECTIVE: This study aimed to identify the risk factors for anterior knee pain (AKP) after medial patellofemoral ligament reconstruction (MPFLR).
METHODS: Patients aged 15-35 years who underwent isolated MPFLR between 2012 and 2022 were included in the study. These patients were divided into two groups (AKP and control group). Patient demographics and preoperative and postoperative clinical outcomes between the two groups were assessed and compared. Univariate logistic regression analysis was performed to explore the potential risk factors associated with postoperative AKP. Subgroup analysis stratified the results based on the time to return to sports (RTS) (>9 and ≤9 months). Furthermore, Spearman correlation analysis was performed to investigate the association between Kujala score and time to RTS.
RESULTS: A total of 206 patients were included (AKP, n = 59; control, n = 147). At the 2-year follow-up, patients with AKP demonstrated a shorter duration in returning to their pre-injury activity level compared to those without AKP (9.0 ± 3.6 vs. 10.3 ± 2.7 months, p < 0.05). RTS earlier than 9 months after MPFLR was the only significant risk factor associated with postoperative AKP (odds ratio, 2.13, 95% confidence interval, 1.03-4.39; p < 0.05). Further subgroup analysis revealed that patient RTS earlier than 9 months exhibited worse patient-reported outcomes in both the total cohort and control group (p < 0.05). Furthermore, among patient RTS within 9 months, a longer recovery duration before RTS strongly correlated with a higher Kujala score (R = 0.670, p < 0.001).
CONCLUSIONS: Young patients who RTS at their pre-injury levels before 9 months after MPFLR have a higher incidence of postoperative AKP and poorer functional outcomes compared to those who delay their return. Specifically, within the first 9 months after MPFLR, the earlier the RTS, the more severe the AKP symptoms. Careful consideration of the timing for RTS may help reduce the incidence of postoperative AKP.
METHODS: Level III.

Background: Anterior knee pain is a common reason for referral to a pediatric orthopedic surgeon. Although previous studies have found that adults with anatomic risk factors for patellofemoral instability (patella dislocation) are predisposed to anterior knee pain, no studies have elucidated the relationship between anatomic risk factors for patellofemoral instability and anterior knee pain in children. Purpose: We sought to characterize common radiographic findings in adolescent patients with a chief complaint of anterior knee pain and to determine the prevalence of abnormal patellofemoral morphology. Methods: We conducted a retrospective review of patients 13 to 18 years old with anterior knee pain at a single tertiary care metropolitan institution from 2016 to 2021. X-rays and magnetic resonance imaging (MRI) were evaluated in those diagnosed with \"chondromalacia patellae,\" \"chondromalacia,\" \"patellofemoral disorders,\" or \"anterior knee pain.\" Patella alta, tibial tubercle-trochlear groove (TT-TG) distance, tubercle height, Wiberg patella type, patellar tilt, and trochlear dysplasia characterization were recorded. Results: Of the 293 adolescents with anterior knee pain included, 62 had bilateral anterior knee pain. Of the 172 MRIs, 72 (42%) met criteria for patella alta, Caton-Deschamps Index (CDI) >1.3, 35% had a TT-TG distance >15 mm, and 32% had lateral patellar tilt >15°. Magnetic resonance imaging findings included infrapatellar fat pad signal hyperintensity (41%) and patellofemoral dysplasia (23%). Of all 293 adolescents, 74% had images showing abnormal patellofemoral morphology, of which 30% had a history of 1 or more patellar dislocation. Overall, 40% of the adolescents had surgery, most commonly medial patellofemoral ligament (MPFL) reconstruction (18%). Conclusions: In this retrospective review, nearly 3/4 of adolescents with anterior knee pain had images showing abnormal patellofemoral morphology, including patella alta, increased TT-TG distance, trochlear dysplasia, or abnormal lateral patellar tilt; only 18% had MPFL surgery. These findings suggest that primary care providers might consider obtaining X-rays and/or MRIs to evaluate for pathology that warrants orthopedic evaluation.

OBJECTIVE: To explore the relationship between knee crepitus, quadriceps muscle thickness and isometric strength in individuals with patellofemoral pain (PFP).
METHODS: Cross-sectional.
METHODS: Individuals with PFP.
METHODS: Participants with PFP underwent assessments for presence, frequency and severity of knee crepitus. Real-time ultrasound images of the quadriceps muscles (rectus femoris, vastus medialis and lateralis) at rest and during contraction were obtained, muscle thickness was measured in both conditions. Maximal voluntary isometric contraction tests were performed to measure knee extensor strength. The relationship between knee crepitus and quadriceps muscle thickness and knee extensor strength was explored using logistic and linear regressions.
RESULTS: Sixty individuals with PFP were included (age: 24; 60% women; 38% with crepitus). Knee crepitus severity was related to rectus femoris and vastus medialis thickness during rest (R2 = 0.19 and 0.09, respectively) and contraction (R2 = 0.16 and 0.07, respectively) and with vastus lateralis during contraction (R2 = 0.08). Isometric knee extensor strength was not related to knee crepitus presence, frequency, or severity.
CONCLUSIONS: Higher severity of knee crepitus is related to lower quadriceps muscle thickness in individuals with PFP. There is no relationship between the presence and frequency of knee crepitus with quadriceps muscle thickness or knee extensor strength.

Objectives: This study aims to evaluate the patellar height changes after distal femur (DF) endoprosthetic replacement (EPR) and its impact on anterior knee pain (AKP) and range of motion (ROM). Methods: A retrospective review of three institutions\' databases was performed. The patellar height was determined using the modified Insall-Salvati ratio (MIS), the Blackburne-Peel (BP) and the Caton-Deschamps (CD) indexes. Data regarding AKP and ROM were collected. Results: A total of 199 patients were included. The mean age at presentation was 37.9 ± 23.1 years. The mean one-year follow-up MIS, BP and CD were 1.52 (sd: 0.41), 0.82 (sd: 0.33) and 0.93 (sd: 0.33). Patellar height decreased significantly compared to the pre-operative values according to all three scores (p < 0.001). AKP was reported by 34 (17.1%) patients at 1 year follow-up. Patients with patella baja (MIS < 1.2) or pseudo patella baja (CD < 0.6) had a higher incidence of AKP (p = 0.037 and p = 0.024, respectively). The mean flexion ROM was 91°, with a direct correlation with patellar height (MIS p = 0.020, BP p = 0.036 and CD p = 0.036). Conclusion: The restoration of the native position of the joint line in DF EPR is important to maintain optimal patellofemoral biomechanics. Despite surgeons\' tendency toward a reduction in patellar height with respect to pre-operative values, an increase in patellar height might help to achieve better knee flexion and reduce AKP.

BACKGROUND: Patellofemoral pain (PFP) is a prevalent chronic condition characterized by retropatellar or peripatellar pain exacerbated by various knee flexion-based activities. Previous research has highlighted the impact of psychological constructs on pain and function in chronic musculoskeletal pain conditions, yet their influence on physical activity in PFP cohorts remains unexplored. We aimed to evaluate whether pain self-efficacy and pain catastrophizing predict variations in steps per day and moderate to vigorous physical activity (MVPA) among individuals with PFP.
METHODS: Cross-sectional observational study.
METHODS: Thirty-nine participants (11 males) with PFP were included. Dependent variables were steps per day and minutes of MVPA. Independent variables were pain self-efficacy and pain catastrophizing, measured by the pain self-efficacy questionnaire and the pain catastrophizing scale. Participants were given an ActiGraph wGT3X-BT for 7 days to assess physical activity. Correlations were assessed between psychological measures and physical activity, and a simple linear regression was performed on psychological variables that correlated with physical activity. Alpha was set a priori at P < .05.
RESULTS: Pain self-efficacy scores displayed a moderate association with steps per day (rho = .45, P = .004) and a weak association with MVPA (rho = .38, P = .014). Pain catastrophizing scores exhibited no significant associations with physical activity (P < .05). Regression models affirmed pain self-efficacy scores as significant predictors of both steps per day (F1,37 = 10.30, P = .002) and MVPA (F1,37 = 8.98, P = .004).
CONCLUSIONS: Psychological measures continue to demonstrate value to clinicians treating PFP. Pain self-efficacy scores were moderately associated with steps per day and weakly associated with MVPA, explaining nearly a fifth of the variation in physical activity. Clinicians should prioritize the assessment of pain self-efficacy when treating individuals with PFP, potentially employing psychological interventions to improve physical activity in the PFP population.