Tommy John is the eponym for the surgical procedure performed to reconstruct the medial ulnar collateral ligament (MUCL) on the inner aspect of the elbow. This procedure was first conceived of by LA Dodgers team orthopaedic surgeon, Dr Frank Jobe, in 1974 on Dodgers baseball pitcher Tommy John. Tommy John was able to resume pitching for the Dodgers 18 months later, in 1976. He continued 14 more successful seasons on various teams until retirement in 1989, with 164 wins after surgery. Although Tommy John failed to be elected to the National Baseball Hall of Fame, Dr Jobe was honored during Hall of Fame week in 2013.
MUCL is the main stabilizer on the inner aspect of the elbow joint that prevents abnormal outward elbow motion as in a dislocation. It connects the humerus (upper arm bone) to the ulna bone of the forearm. The majority of MUCL injuries occur in overhead throwing athletes, such as baseball pitchers, javelin throwers, and football quarterbacks. The first reported case of MUCL injury was in a javelin thrower in 1946, but it was not until 1974 when the first surgical treatment was performed on baseball pitcher Tommy John.
Most injuries occur as a result of repetitive sub-threshold valgus (outward) force on the MUCL. Occasionally, acute full tears can occur as a result of single supra-max threshold throw that manifests as an agonizingly painful pop.
During late cocking phase of the throwing motion, the shoulder is maximally externally rotated by the rotator cuff and a significant amount of strain is placed on the MUCL of the elbow with high tensile stress on this ligament. The angular acceleration and velocity of the ensuing ball delivery during the acceleration phase of throwing converts a 5 oz baseball to be as high as equivalent to hanging 3 twenty-pound medicine balls off the hand.
Lessons may be learned from the javelin throwing technique to minimize injuries to the MUCL. Javelin throwing emphasizes the throwing hand to be as high as possible, which calls for shoulder abduction of higher than 120-130 degrees, so that as the arm moves forward with internal rotation of the arm, the elbow can be brought forward early in order to reach a position directly in front of and above the shoulder to minimize excessive valgus stress on the MUCL. Insufficient shoulder abduction when dropping lower than 90-100 degrees allows the elbow to drop low and results in increased valgus force on the elbow joint.
The 3 major contributors to MUCL injuries are arm throwing mechanics, throwing volume, and throwing velocity. A major indirect cause for MUCL injury is rotator cuff weakness. The higher the shoulder is abducted, the greater the need for rotator cuff to stabilize the shoulder joint. Ironically, as the shoulder is abducted above horizontal, maximal demand calls for the smallest of the four rotator cuff muscles, the teres minor, to maintain a centered shoulder joint. With rotator cuff fatigue, the arm no longer can be raised high, which results in dropping of the shoulder height during the cocking phase. A dropped arm during acceleration permits greater valgus stress on the MUCL.
When non-surgical management fails, Tommy John (TJ) procedure may be performed as a last resort. There has been many variations and modifications since the originally described technique. However, the mainstay of this procedure is to use a piece of tendon from another part of the body, or from an organ donor, and secure it to the natural position where the normal MUCL exists. A representative video can be viewed here – https://youtu.be/Iyo8o8STQIQ
Promulgated by Tommy John’s miraculous come back against all odds, the Tommy John procedure, as it has ever since been known as, has become increasingly popular. As of 2019, at least 1 in 4 MLB pitchers and 15% of minor league pitchers have undergone TJ in their career. This increased number of procedures is directly related to 2 major driving forces — increased sophistication with surgery and the significantly increased average pitching velocity. Average pitching velocity in 1974 was around 88 mph, today’s average being 94 mph. Pitchers are not even considered a contender unless they have the heat of at least a 90 mph pitch.
Abnormal MRI findings are quite common even in those asymptomatic individuals. Up to 85% of asymptomatic minor league pitchers and 87% of asymptomatic major league pitchers may have abnormal elbow MRI. Treatment is based on proper diagnosis differentiating physical findings of vagus laxity from vagus instability. Need of surgery from actual MUCL insufficiency is based on documented disability from symptomatic MUCL injury either with or without vagus laxity.
With the ever increasing number of surgeries performed, a natural consequence that follows is the rise in the number of re-tears and repeat surgeries. Follow-up records among professional pitchers indicate around 7% may need revision TJ surgery by 4 years. However, the most concerning figure being that we see the highest rise in TJ surgeries is in the 15-19 year age group. Again, this is a direct consequence of the unhappy triad of improper throwing arm mechanics, excess volume, and the overwhelming desire to throw fast.
Although a good 80% MLB pitchers may return to play at least one game after an average of almost 17 months, only about 2/3 are able to return to the same level of pitching ability for more than 10 games (keeping in mind that 162 total games are played by each MLB team each season, and pitchers normally pitch between 30 and 70 games per season). Over 50% returned to DL because of injuries to the throwing arm. Outfielders have the best return to play (RTP) of 89% back to prior level, while catchers have the worst RTP of 50% to prior level. This is obviously due to the volume of throwing for catchers (there is no relief catcher), as well as the higher stress to the arm in general when throwing from a crouched position.
The risk for MUCL injury could be lessened by improving arm position throwing mechanics and monitoring throwing volume. Fundamental to these is a strong rotator cuff. Stronger rotator cuff will maintain that needed shoulder elevation, and greater endurance from a strong rotator cuff will permit greater volume of throw without disrupting the mechanics. High throwing velocity is permitted, as long as the technique is good. The common link to a pitcher’s injury, either the shoulder or the elbow, is a weak and fatigued rotator cuff. So it behooves all overhead throwing athletes to pay particular attention to maintain a strong and responsive rotator cuff.