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Background: Arthrogenic muscle inhibition (AMI), a process in which quadriceps activation failure is caused by neural inhibition, is common following knee injury or surgery. No classifications exist to describe the variable presentations of AMI following knee injury. Indications: AMI can result in significant morbidity following knee injury, and it is essential to recognize and treat. It is crucial to identify patients at higher risk of postoperative complications as surgery should be delayed for specific rehabilitation programs. Understanding the pathophysiology of AMI is vital as this can guide therapeutic interventions. Technique Description: AMI following knee injury can present in a variety of ways including inhibition of the vastus medialis obliquus (VMO) muscle, extension deficits due to hamstring contracture, as well as chronic extension deficits. They also respond differently to conventional treatment modalities and often require longer and specific rehabilitation programs. Therefore, we propose a classification to define these different presentations. Results: Grade 0 is a normal VMO contraction. Grade 1a is when VMO contraction is inhibited but activation failure is reversible with simple exercises while Grade 1b requires longer and specific rehabilitation programs. Grade 2a is when VMO contraction is inhibited with an associated extension deficit due to hamstring contracture, but activation failure and loss of range of motion is reversible with simple exercises. However, Grade 2b is refractory to simple exercises, and longer and specific rehabilitation programs are required. Grade 3 is a chronic extension deficit that is irreducible without extensive posterior arthrolysis. Conclusion: In conclusion, AMI is a process in which quadriceps activation failure is caused by neural inhibition and is common following knee injury or surgery. Not taking AMI into account preoperatively can result in a very high risk of stiffness postoperatively. We propose a classification for AMI following knee injury or surgery, which describes different presentations and can be used to guide management.

Background: Ramp lesions are longitudinal lesions of the meniscocapsular complex of the posterior horn of the medial meniscus. These lesions are poorly recognized, difficult to diagnose, and require specific arthroscopic exploration. Ramp lesions are typically associated with anterior cruciate ligament rupture and have important biomechanical consequences as they result in increased anterior tibial translation and external rotation. Suture hook repair through the posteromedial portal is safe and provides a high healing rate. Indications: Spontaneous healing of ramp lesions is rarely observed, and repair is indicated for all lesions with the involvement of meniscotibial ligament. The choice of a posteromedial repair technique with vertical suture performed under visual control allows restoration of the continuity of meniscotibial ligament and effective healing of these lesions. Technique Description: Standardized arthroscopic exploration with systematic visualization of the posteromedial compartment using the transnotch technique is a crucial point to diagnose these lesions. The use of transillumination and a needle allows to palpate the lesion with the tip of the needle in case of doubt (hidden lesion) before performing the posteromedial portal safely. By using the transnotch vision and by introducing the instruments through the posteromedial portal, debridement with the shaver and repair with the hook of the lesion are performed under visual control. Vertical repair is performed by taking care to pass the hook through the meniscotibial ligament by perforating the deep face of the capsular portion and anterior portion of the ramp lesion. Similarly, it is recommended not to catch too much meniscal tissue on the anterior margin side to remain in the red zone and not to perforate the meniscus in the avascular zone to avoid secondary lesions caused by the “cheese wire” effect of the sutures in the white zone. Results: This technique has allowed us to reduce our percentage of secondary meniscectomy after ramp lesion repair from 25% using a standard arthroscopic exploration and meniscal repair technique through the anterior portal to 11.3% using a arthroscopic exploration and repair technique through the posteromedial portal at 4 years of follow-up. Discussion/Conclusion: Systematic use of the transnotch vision and repair through the posteromedial portal are recommended for the management of these lesions, which demonstrate serious mechanical and clinical consequences.