“What happens to the human body when the patellar tendon is torn?” asked a recent article in Sports Illustrated.
The answer, in the case of injured basketball coach Chris Finch, was a displaced kneecap. Finch had been on the sidelines when one of his players exited the court at pace and clattered into him.
“When I went to grab for my knee, there was no kneecap there – and that’s when I thought, ‘OK, this is going to be a serious one,’” he said afterwards (with impressive understatement).
While most patellar tendon tears aren’t quite so dramatic as Finch’s, they are a significant injury and can take considerable time to treat and heal. Let’s look at them in a bit more detail.
What does the patellar tendon do?
You may recall from biology lessons that tendons connect muscles to bones (as opposed to ligaments, which go from bone to bone). Somewhat confusingly, the patellar tendon’s job is to link two bones together: the kneecap (patella) to the shinbone. Which is why it’s sometimes called the patellar ligament. Either way, its main function is to help us flex and straighten our legs.
How do people tear a patellar tendon?
Usually, through a direct blow to the kneecap. But since the patellar tendon is extremely tough, it takes significant energy to do this. So the classic injury is a fall, when the flexed knee hits the ground with considerable force. But it’s also a common “jumping injury” – the damage here is done when you jump and plant the foot with the knee bent, landing badly.
Are some patellar tendon tears worse than others?
Yes, there’s a wide spectrum of possible damage. For simplicity, though, we tend to put them in two categories:
Partial tear – this is where the tissue fibres in the tendon become overstretched and frayed, but the tendon stays attached to the kneecap. A partial tear can also happen incrementally over time, for instance through repetitive overuse of the knee joint
Complete tear – also known as a rupture, this is where the tendon detaches totally from the bone. The rupture usually happens close to the kneecap, within about 1cm or so of the bone
If you’ve torn your patellar tendon, you may be asked to have some scans to confirm the diagnosis and work out the extent of the damage – an x-ray to check the bone and / or an MRI scan to get a better view of the tendon tissues.
Could a partial patellar tendon tear heal on its own?
Yes, it’s possible. While a complete rupture will almost certainly need a tendon repair operation, ideally within two weeks of the injury, a partial tear often responds well to conservative (nonsurgical) treatment. In the early days, the knee is likely to be swollen and painful. It may take several weeks of rest, often while using crutches to avoid putting weight on the joint, before it settles down. After that, we’re likely to recommend you for rehab with a physiotherapist. When it comes to a torn patellar tendon, this is often critical.
Why are rehab and physio so important?
One reason is that, because they have a limited blood supply, tendons are quite slow to heal. So when the pain and swelling ebb away, it’s tempting to race back into sport etc as soon as possible. But this is often a mistake, because it risks tearing the weakened fibres all over again. One potential result is tendinopathy, where the tendon repeatedly flares up and becomes painfully inflamed. An individualised programme of physio, with tailored exercises, helps avoid this by building up strength in the supporting muscles around the knee. So it’s best to think of patellar tendon recovery as a marathon rather than a sprint. It can take even a year or two to restore full strength. But a well-planned rehab programme makes a huge difference to the outcome.
