Medial epicondylitis is degeneration of the common flexor-pronator tendon origin at the inside of the elbow. The muscles affected — primarily the flexor carpi radialis and pronator teres — are responsible for wrist flexion and forearm rotation toward the palm. Any activity that repetitively loads those movements under resistance is a potential driver: golf swings, overhead throwing, racquet sports with heavy topspin, rock climbing, and — in my practice — extended fly casting, which combines sustained grip tension with repetitive wrist flexion across a full casting session.
The pain is localized to the medial epicondyle, typically worsens with resisted wrist flexion and forearm pronation, and often radiates a short distance down the medial forearm. It is, in both pathological mechanism and rehabilitation approach, the mirror image of tennis elbow — and treating it as anything else is the first error most patients with this condition encounter.
Same pathology, opposite side
Lateral and medial epicondylitis are the same disease at different anatomical sites. Both represent angiofibroblastic tendon degeneration — a failed healing response in chronically overloaded tendon tissue characterized by disorganized collagen and neovascularization, without the acute inflammatory infiltrate that the term "itis" implies. This histological finding, first characterized by Nirschl and Pettrone in 1979, is the reason that anti-inflammatory treatments alone — oral NSAIDs, repeated corticosteroid injections — do not produce durable improvement. The pathology is degenerative, not primarily inflammatory, and the treatment must address tendon remodeling, not inflammation suppression.
- Common extensor origin — primarily ECRB
- Pain on outside of elbow over lateral epicondyle
- Provoked by resisted wrist extension and gripping
- Aggravated by backhand strokes, typing, gripping tools
- Eccentric wrist extension loading — Tyler Twist (standard)
- Common flexor-pronator origin — FCR and pronator teres
- Pain on inside of elbow over medial epicondyle
- Provoked by resisted wrist flexion and forearm pronation
- Aggravated by golf, throwing, fly casting, climbing
- Eccentric wrist flexion loading — Tyler Twist (reverse)
"Golfer's elbow and tennis elbow are the same pathological process — tendon degeneration from repetitive overload — on opposite sides of the joint. The rehabilitation principles are identical. The exercises are mirror images of each other."
The rehabilitation protocol — what the evidence supports
The treatment framework for medial epicondylitis mirrors the evidence-supported approach for lateral epicondylitis, with the exercise mechanics adjusted for the flexor-pronator group rather than the extensor group. Eccentric loading — slowly lowering a load through the lengthening phase of the muscle contraction — is the rehabilitation stimulus that drives tendon remodeling. For medial epicondylitis, this means eccentric wrist flexion: starting with the wrist in flexion and slowly allowing it to extend against a light resistance, loading the flexor-pronator origin as it lengthens.
The nerve you need to know about — when it's not just the tendon
The ulnar nerve runs directly behind the medial epicondyle in the cubital tunnel, immediately adjacent to the flexor-pronator origin. Ulnar nerve involvement is the complicating factor in medial elbow pain that does not respond as expected to tendon rehabilitation alone, and it is more common in medial epicondylitis than most patients are told.
If you have been treated for golfer's elbow and your symptoms include numbness or tingling in the ring and little finger — particularly at night or when the elbow is held in a flexed position — the diagnosis may be more complex than isolated tendinopathy. Medial elbow pain with ulnar nerve symptoms requires evaluation by someone who can assess both the tendon and the nerve as contributing factors. Treating only the tendon while an irritated ulnar nerve goes unaddressed produces incomplete improvement regardless of how correctly the loading protocol is performed.
Cortisone injection into the common flexor-pronator origin can provide meaningful short-term pain relief that allows a patient to begin the loading program, and is a reasonable adjunct in moderate-stage disease. It should not be used repeatedly as the primary treatment, and it should be performed with caution near the medial epicondyle given the proximity of the ulnar nerve — image-guided injection is preferable when available. Time and loading remain the primary drivers of lasting improvement. Most cases resolve over six to twelve months with consistent, correctly performed eccentric loading and activity modification.
Watch the eccentric loading demo for both medial and lateral epicondylitis on Instagram.
@formandfunctionmd →- Nirschl RP, Pettrone FA. Tennis elbow: the surgical treatment of lateral epicondylitis. Journal of Bone and Joint Surgery (American Volume). 1979;61(6):832–839. doi:10.2106/00004623-197961060-00005
- Stasinopoulos D, Stasinopoulos I. Comparison of effects of exercise programme, pulsed ultrasound and transverse friction in the treatment of chronic patellar tendinopathy. Clinical Rehabilitation. 2004;18(4):347–352. doi:10.1191/0269215504cr757oa
- Tyler TF, Thomas GC, Nicholas SJ, McHugh MP. Addition of isolated wrist extensor eccentric exercise to standard treatment for chronic lateral epicondylosis: a prospective randomized trial. Journal of Shoulder and Elbow Surgery. 2010;19(6):917–922. doi:10.1016/j.jse.2010.05.013
- Sims SE, Miller K, Elfar JC, Hammert WC. Non-surgical treatment of lateral epicondylitis: a systematic review of randomized controlled trials. Hand. 2014;9(4):419–446. doi:10.1007/s11552-014-9642-x
- Descatha A, Leclerc A, Chastang JF, Roquelaure Y. Medial epicondylitis in occupational settings: prevalence, incidence and associated risk factors. Journal of Occupational and Environmental Medicine. 2003;45(9):993–1001. doi:10.1097/01.jom.0000085893.86622.7d