This prospective single-center observational cohort study will evaluate the relationship between anterior knee pain and patellar tendon elasticity after infrapatellar tendon-split tibial intramedullary nailing. Adult patients undergoing standard tibial intramedullary nailing through an infrapatellar tendon-split approach will be enrolled after ethics approval. Patellar tendon elasticity will be assessed using shear-wave ultrasound elastography before surgery and during follow-up at 6 weeks, 3 months, and 6 months. Clinical outcomes will include anterior knee pain severity, patellofemoral function, tendon-related symptoms, and knee range of motion. Inter-rater reliability between two independent radiologists will also be evaluated.
Anterior knee pain is a frequent complaint after tibial intramedullary nailing, but the role of patellar tendon biomechanical changes remains unclear. The infrapatellar tendon-split approach may lead to tendon healing, remodeling, and fibrosis, which could alter tendon elasticity and contribute to persistent pain and functional limitation. This study aims to prospectively investigate whether changes in patellar tendon elasticity are associated with anterior knee pain after infrapatellar tendon-split tibial intramedullary nailing. This is a prospective, single-center, non-interventional observational cohort study. Adult patients aged 18 to 65 years with unilateral tibial shaft or metaphyseal fractures treated with standard infrapatellar tendon-split tibial intramedullary nailing will be enrolled consecutively after institutional ethics approval. Only patients enrolled after ethics approval will be included in the registered cohort. Patellar tendon elasticity will be measured using shear-wave ultrasound elastography at four predefined time points: preoperatively, 6 weeks, 3 months, and 6 months postoperatively. Ultrasound assessments will be performed according to a standardized protocol by two independent radiologists, and inter-rater reliability will be assessed. Additional ultrasound parameters will include tendon thickness on B-mode imaging and Doppler neovascularization. Clinical outcomes will include anterior knee pain assessed with a visual analog scale, patellofemoral function assessed with the Kujala Anterior Knee Pain Scale, tendon-related symptoms assessed with the VISA-P questionnaire, pressure pain sensitivity, and active knee range of motion. The primary objective is to determine whether change in patellar tendon elasticity is associated with anterior knee pain at 6 months. Secondary objectives are to examine associations between tendon elasticity and functional scores, range of motion, tendon thickness, Doppler findings, and inter-rater measurement reliability.
Study Type
OBSERVATIONAL
Enrollment
50
Standard-of-care tibial intramedullary nailing performed through an infrapatellar longitudinal patellar tendon split approach. The procedure is not assigned by the protocol; only patients undergoing this routine surgical approach are observed.
Non-invasive shear-wave ultrasound elastography of the patellar tendon performed at predefined study visits using a standardized imaging protocol.
Bagcilar Training and Research Hospital
Istanbul, Istanbul, Turkey (Türkiye)
Change in patellar tendon elasticity from baseline to 6 months
Patellar tendon elasticity measured by shear-wave ultrasound elastography in kilopascals. The primary analysis will assess the longitudinal change from baseline to 6 months.
Time frame: Preoperative baseline and 6 months postoperatively
Change in patellar tendon elasticity from baseline to 3 months
Change in patellar tendon elasticity measured by shear-wave ultrasound elastography.
Time frame: Preoperative baseline and 3 months postoperatively
Anterior knee pain severity
Anterior knee pain severity will be assessed using the Visual Analog Scale. The Visual Analog Scale ranges from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate worse anterior knee pain.
Time frame: Baseline and postoperative 6 weeks, 3 months, and 6 months
Patellofemoral function
Patellofemoral function will be assessed using the Kujala Anterior Knee Pain Scale. The scale ranges from 0 to 100 points, with higher scores indicating better patellofemoral function and fewer anterior knee symptoms.
Time frame: Preoperative baseline, 3 months, and 6 months
Patellar Tendon-Related Symptoms and Function
Patellar tendon-related symptoms and function will be assessed using the Victorian Institute of Sport Assessment-Patella questionnaire. The questionnaire ranges from 0 to 100 points, with higher scores indicating fewer patellar tendon-related symptoms and better function
Time frame: Preoperative baseline, 3 months, and 6 months
Active knee range of motion
Active knee flexion and extension lag measured with a goniometer.
Time frame: Preoperative baseline, 6 weeks, 3 months, and 6 months
Patellar tendon thickness
Patellar tendon thickness measured on B-mode ultrasound.
Time frame: Preoperative baseline, 6 weeks, 3 months, and 6 months
Doppler neovascularization
Semiquantitative Doppler neovascularization score.
Time frame: Preoperative baseline, 6 weeks, 3 months, and 6 months
Pressure Pain Sensitivity
Pressure pain sensitivity will be assessed by recording pain intensity during a standardized pressure pain assessment using the Visual Analog Scale. The Visual Analog Scale ranges from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate greater pressure pain sensitivity.
Time frame: 6 weeks, 3 months, and 6 months
Inter-rater reliability of shear-wave elastography measurements
Agreement between two independent radiologists assessed using intraclass correlation coefficients.
Time frame: Baseline, 6 weeks, 3 months, and 6 months
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.