The patellar height measurement is fundamental for surgical planning in patellar instability. The Caton–Deschamps index (CDI) is a widely employed method, but a gold standard is still lacking. The aim of this study was to evaluate the reliability and reproducibility of the CDI in a patellar height assessment and to hypothesize its employment in the preoperative planning of patellar stabilization surgery. A total of 29 cases of recurrent patellar instability undergoing surgical treatment were analyzed. The preoperative and postoperative CDI were measured by six different raters (three seniors and three juniors). The interclass correlation coefficient (ICC) of the six raters was calculated to evaluate the interobserver agreement. The seniors’ and juniors’ measurements were compared to assess the CDI reproducibility. The Fleiss kappa was calculated among the six raters to estimate the agreement in favor of an anterior tibial apophysis (ATA) transposition surgery. This study shows excellent absolute agreement in terms of the ICC for the raters’ average and for single raters as units, both preoperatively (p < 0.001) and postoperatively (p < 0.001). The agreement of the surgical choice between the six observers corresponds to “substantial agreement”. This study demonstrates that the CDI is reliable and reproducible, and it could represent a valuable tool in the clinical assessment, treatment choice and pre-surgical planning of patellar instability surgery.

Background: The SARS-CoV-2 pandemic drastically changed daily life activities and medical practice, leading to a reorganization of healthcare activities. People spent two months in home-isolation, changing their daily habits and undertaking a more sedentary lifestyle. Change in lifestyle is related to important consequences in knee pathologies. The aim of this study was to evaluate the outpatient activity for knee pathologies before and after lockdown in terms of incidence, severity, diagnosis, and treatment. Methods: Medical records of patients with knee pathology in outpatient follow-up at IRCCS Istituto Ortopedico Galeazzi in Milan (Italy) were analyzed in the time frame 4 May–4 September 2020 and compared with patients examined between 4 May and 4 September 2019. Results: A significant increase of knee diagnoses associated to patellofemoral disorders in 2020 was found (p = 0.004). In addition, physiotherapy was significantly more prescribed in 2020 than in 2019 (p = 0.012). Conclusions: The SARS-CoV-2 pandemic lockdown did not drastically change knee pathology, but it may have had an impact on it, highlighting a summary worsening of patellofemoral disorders associated with other knee diagnoses. Further studies are required to validate this result.

The patellofemoral joint (PFJ) is a complex articulation between the patella and the femur which is involved in the extensor mechanism of the knee. Patellofemoral disorders can be classified into objective patellar instability, potential patellar instability, and patellofemoral pain syndrome. Anatomical factors such as trochlear dysplasia, patella alta, and the tibial tuberosity–trochlear groove (TT-TG) distance contribute to instability. Patellofemoral instability can result in various types of dislocations, and the frequency of dislocation can be categorized as recurrent, habitual, or permanent. Primary patellar dislocation requires diagnostic framing, including physical examination and imaging. Magnetic resonance imaging (MRI) is essential for assessing the extent of damage, such as bone bruises, osteochondral fractures, and medial patellofemoral ligament (MPFL) rupture. Treatment options for primary dislocation include urgent surgery for osteochondral fragments or conservative treatment for cases without lesions. Follow-up after treatment involves imaging screening and assessing principal and secondary factors of instability. Detecting and addressing these factors is crucial for preventing recurrent dislocations and optimizing patient outcomes.

The patellofemoral joint (PFJ) is a complex articulation between the patella and the femur, in-volved in the extensor mechanism of the knee. Patellofemoral disorders can be classified into ob-jective patellar instability, potential patellar instability, and patellofemoral pain syndrome. An-atomical factors such as trochlear dysplasia, patella alta, and tibial tuberosity-trochlear groove (TT-TG) distance contribute to instability. Patellofemoral instability can result in various types of dislocations, and the frequency of dislocation can be categorized as recurrent, habitual, or per-manent. Primary patellar dislocation requires diagnostic framing, including physical examina-tion and imaging. Magnetic resonance imaging (MRI) is essential for assessing the extent of damage, such as bone bruises, osteochondral fractures, and medial patellofemoral ligament (MPFL) rupture. Treatment options for primary dislocation include urgent surgery for oste-ochondral fragments or conservative treatment for cases without lesions. Follow-up after treat-ment involves imaging screening and assessing principal and secondary factors of instability. Detecting and addressing these factors is crucial for preventing recurrent dislocations and opti-mizing patient outcomes.