Flexor Tendon

Non-Operative Care

The tendon on the inner side of the elbow is the Flexor Tendon. This is major attachment for the muscles in the forearm and wrist that power wrist and finger bending (“flexion”) and rotation of the hand into a palm down position (“pronation”). These muscles are clearly important in throwing a ball, from gripping the ball to putting spin on a breaking pitch. With frequent throwing, this tendon can become overloaded. This leads to inflammation of the tendon (“tendonitis”) and sometimes degeneration of the tendon. In more chronic or severe cases, the tendon may partially tear little by little. Rarely, the tendon may tear completely. Fortunately, most of the time these flexor tendon injuries will respond well to rest and time, but sometimes they don’t. In that case, surgery to remove degenerated tendon tissue and repair of the tendon is necessary. Though infrequently needed, the results are good, and the recovery is much faster than after UCL reconstruction.

These muscles are clearly important in throwing a ball, from gripping a ball to putting a spin on a breaking pitch.

Flexor Tendon MRIs

Normal Flexor Tendon and UCL

Normal flexor tendon and UCL

Normal Flexor Tendon Attachment

Normal flexor tendon attachment

Flexor Tendon Tear

Flexor tendon partially detached from bone.

Flexor Tendon Partial Tear

Partially torn flexor tendon.

Surgical Repair

Medial Elbow Pre-op for Flexor Tendon Repair

Figure 1

Figure 1— Inner side of the elbow before the incision is made. The flexor tendon is drawn at its attachment to the humerus (arm bone).

Flexor Tendon Exposed

Figure 2

Figure 2 — An incision through the skin, where the flexor tendon is the white sheet/cord of tissue in the center of the incision.

Incised Flexor Tendon

Figure 3

Figure 3 — The incision is through the flexor tendon itself. The white shiny tissue is the healthy tissue, while the grayish-brown tissue with a gelatinous texture is the degenerative scar tissue accumulating where the tendon had partially torn. This is the source of the pain.

Flexor Tendon After Debridement

Figure 4

Figure 4 – After the degenerative tissue is removed there is a defect or gap in the tendon where the scar tissue used to be. This is the hollow area in the center of the tendon in this picture. The yellow area is the medial epicondyle of the humerus (the bump of bone on the inner side of the elbow). This is where I will reattach the flexor tendon during the repair portion of the operation.

Flexor Tendon Tissue Removed

Figure 5

Figure 5 – This is the tissue that was removed from the tendon.

Repaired Flexor Tendon

Figure 6

Figure 6 – I have now repaired the tendon by reattaching it to the bone and reinforcing the damaged area. The remaining part of the tendon is closed with sutures.


After this sort of surgery the athlete can usually resume throwing by three months post-op and gradually progress to full activities. Typically within 5 – 6 months the pitcher will be back on the mound.

Dr. David Lintner - Houston Orthopedic Surgeon