The Twins community recently received some concerning news about highly-regarded prospect Royce Lewis. Lewis left the Cedar Rapids Kernels Saturday game with what is being reported as ‘patellar tendinitis’, which has been causing him trouble off-and-on for about a month. But what is ‘patellar tendinitis’ exactly? And what might it mean for Royce going forward? Let’s discuss:
Question 1: Where is the ‘patella tendon’?
The patella tendon is the tendon that goes from your kneecap (also called the patella) down to the upper part of your shin bone (tibia). It is the attachment of your quadriceps muscle group to your lower leg, and it is what allows people to extend the knee.
Question 2: What is ‘patellar tendinitis’?
Patella tendinitis is a term commonly used to refer to activity-related pain that occurs near the attachment of the patella tendon to the patella. The suffix ‘-itis’ is used to indicate inflammation. While the term is commonly used, in actuality a more appropriate term is ‘patella tendinopathy’, which refers to degenerative changes within the tendon in the absence of inflammation (which is more accurately the case in this diagnosis). This difference is important when considering treatment options.
Question 3: Royce is clearly a high-level athlete. Why did he get this problem?
Patellar tendinopathy is also commonly called ‘jumper’s knee’ since it occurs most frequently in athletes that do a lot of jumping. In some studies of professional volleyball and basketball players, the incidence of jumper’s knee has been shown to be more than 30%. It is much less common in non-jumping athletes, but still occurs in around 2-3% of soccer players. I was not able to find any information specifically discussing the incidence in baseball players.
It is unclear exactly why this problem occurs. It is most likely a combination of factors including BMI, flat feet, muscle imbalance in the quad/hamstrings, low flexibility, and intrinsic properties of the patellar tendon. There are likely other factors as well, including overuse.
The area involved is usually located directly at the bottom end of the patella/top part of the tendon. Symptoms usually come on gradually over time. Initially, the knee typically hurts only with activity. Over time, if the condition worsens, pain may begin to be present even at rest.
Question 4: How is patella tendinopathy diagnosed?
The diagnosis is usually fairly clear from the history and physical exam of the athlete. Xrays are usually normal, though in some cases calcifications of the tendon may be visible. An MRI is the standard test to identify the extent of the problem and also to rule out other problems inside the knee. The area of the tendon involved in the problem is typically fairly small- around the size of a couple tic-tacs.
Question 5: How is patella tendinopathy treated?
The most commonly prescribed treatment for patellar tendinopathy is rest from vigorous activity and specific physical therapy exercises (called eccentric exercises). These exercises are designed to strengthen the quad muscles, stretch the hamstrings and ultimately cause favorable adaptation of the knee. The time needed for symptoms to resolve can be highly variable, but often takes at least a few weeks.
When therapy isn’t effective, other treatments can be tried including various injections and ultrasound. At this time, there is no significant evidence that PRP (platelet rich plasma) injections are helpful for this condition, though I suspect it is being considered. There is, to my knowledge, no significant data on stem cell injections for this problem.
Question 6: Is surgery ever needed for patellar tendinopathy?
Rarely, yes. In most studies, around 10% of patients will fail to respond to appropriate conservative treatment. In these cases, surgery may be needed. There are two main options: open surgery and arthroscopic surgery. In either case, the procedure is similar- the area of affected tendon is excised and a small (a few millimeters) part of the patella bone is removed to stimulate healing. Therapy is begun soon after surgery. The success rate for return to sports is around 80% for both surgeries, with return after the arthroscopic version being quicker on average. Usually, 4-6 months is needed for full return to sports after surgery.
Question 7: Is Royce at increased risk of rupturing the patella tendon because of this problem?
No. Having patella tendinopathy does not appear to place anyone at increased risk of having a patella tendon rupture when compared to those without the problem.
Overall, I believe the most likely scenario to be that Lewis’ body is adjusting to playing professional baseball every day and he is having some minor issues as a result. I don’t expect this to be a substantial problem going forward, though the possibility that this requires surgery in the future does exist. Hopefully he will get through rehab quickly and be back on the field soon.