Mohammad Razi - Department of Orthopedic Surgery, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
Saeed Razi - Bone and Joint Reconstruction Research Center, Department of Orthopedics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Haleh Dadgostar - Department of Sports and Exercise Medicine, School of Medicine, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
Peyman Arasteh - Department of MPH, Shiraz University of Medical Sciences, Shiraz, Iran
Mohammad Soleimani - Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
Faezeh Khazaee - Department of Biomedical Engineering, Sciences and Research Branch, Islamic Azad University, Tehran, Iran

Objectives: This study aimed to introduce a novel arthroscopic treatment for medial and posteromedial instability of the knee and present the primary and follow-up results.Methods: All patients who underwent the arthroscopic approach to treat medial and posteromedial corner instability from ۲۰۰۷ to ۲۰۱۷ were included in this report. Overall, ۴۵ patients were included, among which ۷۵.۶% were male. The mean age of patients was ۳۲.۲ ± ۸.۴ years. Overall, ۴۴.۴% and ۱۵.۶% of patients had associated meniscal injuries and chondral lesions, respectively. The mean follow-up duration of patients was ۸۴.۲ ± ۲۵.۳ months.Results: Overall, ۳۷ patients developed a full range of motion (۸۲.۲%), and most patients (۹۵.۶%) showed excellent quadriceps strength (grades ۴ and ۵). All patients had a normal or ۱+ posterior drawer test, Pivot shift test, and Lachman test on physical examination. Moreover, ۶۰% had an associated isolated anterior cruciate ligament injury, ۱۷.۸% had an isolated posterior collateral ligament injury, and ۱۷.۶% had a combination of more than one ligament injury. One patient developed septic arthritis. Two patients experienced pain, and one pain patient developed pain with a bony spur formation in the medial epicondyle. Three patients showed a ۲+ medial collateral ligament (MCL) test (moderate instability) at the final follow-up, all of whom had multi-ligament injuries. All patients, except the three patients who had a failed MCL reconstruction, returned to their previous activities.Conclusion: This study described a novel arthroscopic treatment of MCL injury, and the results showed acceptable postoperative and clinical outcomes. As the use of minimally invasive surgery may minimize multiple complications associated with open surgery, it is suggested that further studies be conducted regarding this approach when faced with patients who have MCL injuries requiring surgery. Level of evidence: IV

Arthroscopy, Instability, knee, medial collateral ligament, Posteromedial corner