A 5 year old female spayed German Short Haired Pointer presented to the Cornell Orthopedics Service for evaluation of left forelimb lameness of 5 months duration. Minor trauma preceded the lameness and the clinical signs worsened over the last 3 weeks. Orthopedic examination, radiographs, and MRI of the left shoulder yielded a diagnosis of Biceps tenosynovitis in this patient. Arthroscopic tenotomy was elected to treat the patient’s lameness. The case was complicated by severe inflammation and proliferation within the shoulder joint, which prevented visualization of the biceps tendon. The arthroscopy was converted to an open procedure and successful tendon release was achieved through transection and removal of approximately 1cm of damaged biceps tendon. The patient’s lameness showed marked improvement within 2 weeks following surgery. Physical therapy and rehabilitation was needed to correct muscle atrophy and manage degenerative joint disease resulting from 5 months of lameness and disuse.