An observational study in Anterior Knee Pain, Patellar Tendon Disorder and Tibial Shaft Fractures, sponsored by Bagcilar Training and Research Hospital. Active, not recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by Bagcilar Training and Research Hospital · Observational
This prospective, single-center observational cohort study evaluates the relationship between anterior knee pain and patellar tendon elasticity after infrapatellar tendon-split tibial intramedullary nailing. Adults treated with standard tibial intramedullary nailing through an infrapatellar tendon-split approach were enrolled consecutively after ethics approval. Patellar tendon elasticity is assessed bilaterally, in the operated and the contralateral non-operated knee, using shear-wave ultrasound elastography before surgery and at 6 weeks and 3, 6 and 12 months postoperatively. The contralateral tendon serves as a within-participant reference. Clinical outcomes include anterior knee pain, patellofemoral function, tendon-related symptoms and knee range of motion. Inter-rater reliability between two independent radiologists is also 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 prospective, single-center, non-interventional cohort study investigates whether changes in patellar tendon elasticity are associated with anterior knee pain after infrapatellar tendon-split tibial nailing.
Adults aged 18 to 65 years with a unilateral tibial shaft or metaphyseal fracture treated with standard infrapatellar tendon-split nailing were enrolled consecutively after institutional ethics approval (50 participants). Patellar tendon elasticity is measured bilaterally with shear-wave ultrasound elastography preoperatively and at 6 weeks and 3, 6 and 12 months postoperatively by two independent radiologists using a standardized protocol. The contralateral tendon serves as a within-participant reference and does not constitute a separate treatment group. Additional ultrasound parameters include tendon thickness on B-mode imaging and Doppler neovascularization. Clinical outcomes include anterior knee pain (visual analog scale), the Kujala Anterior Knee Pain Scale, the VISA-P questionnaire, pressure pain sensitivity and active knee range of motion.
The primary outcome is the change in operated-side patellar tendon elasticity from preoperative baseline to 6 months. Secondary objectives are to examine associations between elasticity changes and anterior knee pain, function, tendon thickness and Doppler findings, and to assess inter-rater reliability. A 12-month visit was added by protocol amendment before any 12-month assessment had been performed, without changing the primary outcome. The prespecified 12-month hypothesis is that side-adjusted elasticity change (operated-side change minus contralateral change) from baseline to 12 months is larger in patients with anterior knee pain at 12 months than in those without.
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This study's enrollment of 50 is below the median of 100 across 1,252 observational studies indexed under Pain.
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Adults with unilateral tibial shaft or metaphyseal fractures treated at Bagcilar Training and Research Hospital with standard infrapatellar tendon-split tibial intramedullary nailing will be enrolled prospectively after ethics approval.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adult patients with unilateral tibial shaft or metaphyseal fractures treated with standard infrapatellar tendon-split tibial intramedullary nailing will be enrolled after institutional ethics approval. Participants will be followed prospectively with bilateral shear-wave ultrasound elastography of the operated and contralateral patellar tendons and clinical assessments at preoperative baseline and at 6 weeks, 3 months, 6 months, and 12 months postoperatively.
Procedure: Infrapatellar tendon-split tibial intramedullary nailing · Diagnostic Test: Shear-wave ultrasound elastography
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.
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: Preoperative baseline and 6 weeks, 3 months, 6 months, and 12 months postoperatively.
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 and 3, 6, and 12 months postoperatively.
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 and 3, 6, and 12 months postoperatively.
Active knee range of motion
Active knee flexion and extension lag measured with a goniometer.
Time frame: Preoperative baseline and 6 weeks, 3 months, 6 months, and 12 months postoperatively.
Patellar tendon thickness
Patellar tendon thickness on the operated and contralateral sides will be measured using B-mode ultrasonography and expressed in millimeters (mm).
Time frame: Preoperative baseline and 6 weeks, 3 months, 6 months, and 12 months postoperatively.
Doppler neovascularization
Semiquantitative Doppler neovascularization score.
Time frame: Preoperative baseline and 6 weeks, 3 months, 6 months, and 12 months postoperatively.
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, 6 months, and 12 months postoperatively.
Inter-rater reliability of shear-wave elastography measurements
Agreement between two independent radiologists assessed using intraclass correlation coefficients.
Time frame: Preoperative baseline and 6 weeks, 3 months, 6 months, and 12 months postoperatively.
Change in operated-side patellar tendon elasticity from baseline to 12 months
Patellar tendon elasticity on the operated side will be measured using shear-wave ultrasound elastography and expressed in kilopascals (kPa). The change from preoperative baseline to 12 months postoperatively will be calculated as the 12-month value minus the baseline value to characterize tendon changes during extended follow-up.
Time frame: Preoperative baseline and 12 months postoperatively
Side-adjusted change in patellar tendon elasticity
Change in operated-side elasticity from preoperative baseline minus the corresponding change in contralateral elasticity, measured by shear-wave ultrasound elastography in kPa.
Time frame: Preoperative baseline and 6 and 12 months postoperatively
Anterior knee pain at 12 months and its association with side-adjusted elasticity change
Anterior knee pain is defined as pain localized to the anterior knee with a Visual Analog Scale score greater than 0 (0-10 scale). Side-adjusted elasticity change from baseline to 12 months will be compared between patients with and without anterior knee pain at 12 months.
Time frame: Preoperative baseline and 12 months postoperatively
Plan to share: No — Individual participant data will not be shared because this is a single-center study with a limited sample size and no predefined external data-sharing agreement. Only aggregate, de-identified study results will be reported in publications and presentations.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Bagcilar Training and Research Hospital