This prospective observational study evaluates the intraoperative energy expenditure of the surgeon during anterior cruciate ligament reconstruction procedures. Energy expenditure and physiological workload will be measured using a wearable Hexoskin shirt during surgery.

The study will compare surgical procedures involving isolated anterior cruciate ligament reconstruction, anterior cruciate ligament reconstruction combined with anterolateral ligament reconstruction, and procedures requiring additional meniscal treatment. The aim is to determine whether anterolateral ligament reconstruction meaningfully increases surgeon workload and whether meniscal procedures are associated with higher intraoperative energy expenditure.

Inclusion Criteria:

• Patients undergoing primary anterior cruciate ligament reconstruction
• Unilateral ACL rupture confirmed by clinical examination and MRI
• Surgery performed by the participating surgeon wearing the Hexoskin device
• Ability to provide written informed consent

Exclusion Criteria:

• Revision ACL reconstruction
• Multiligament knee reconstruction
• Bilateral knee surgery
• Concomitant procedures other than ACL reconstruction, ALL reconstruction, meniscal repair, or partial meniscectomy
• Incomplete intraoperative Hexoskin recording
• Conversion or interruption of the planned surgical procedure

he study population will include patients undergoing primary anterior cruciate ligament (ACL) reconstruction at the participating center. Patients may undergo isolated ACL reconstruction, ACL reconstruction combined with anterolateral ligament (ALL) reconstruction, ACL reconstruction with associated meniscal treatment, or ACL reconstruction combined with both ALL reconstruction and meniscal treatment.

During each surgical procedure, the operating surgeon will wear a Hexoskin device to record intraoperative physiological parameters and estimate energy expenditure. Surgical indication and associated procedures will be determined according to standard clinical practice.

Individual participant data collected during this study will not be made publicly available because informed consent for data sharing was not obtained and data are subject to institutional privacy and ethical restrictions.