Objectives: To describe the percutaneous image-guided treatment of mucoid degeneration of the ACL causing deep knee pain on flexion in patients with advanced knee osteoarthritis.Methods: Five patients with mucoid degeneration of the ACL complicating knee osteoarthritis underwent percutaneous image-guided steroid bupivacaine ACL sleeve injections over a 3-year period.Results: There were four males and one female of mean age 54 (range 48–59 years). Each patient had Kellgren and Lawrence grade 4 medial compartment knee osteoarthritis with coexistent mucoid degeneration of the ACL sleeve. Each patient complained of deep knee pain on flexion as a dominant symptom. Each patient underwent image-guided (CT or ultrasound) steroid bupivacaine injection of the ACL sleeve resulting in symptom resolution and improved mobility for a mean duration of 8 months, (range 6–15 months.)Conclusion: Mucoid degeneration of the ACL should be sought in patients with osteoarthritis presenting with deep knee pain on flexion. Image-guided ACL sleeve injection in affected patients may result in symptom resolution and potential deferral of planned knee replacement surgery.Advances in knowledge: Emphasises Image guided percutaneous treatment of Mucoid degeneration of ACL in patients with knee osteoarthritis.