Just as the ball leaves your racquet, you feel the pain in your knee as you land awkwardly on your right foot; you hear a loud “pop” and the next thing you know, you’re laying on the ground with your knee throbbing. Was it the meniscus? The cartilage? A ligament? Or, all of the above? One thing’s for sure – it’s time to see a doctor.
“Fortunately, most sporting knee injuries are not so severe,” says orthopaedic surgeon, Dr Bernard Lee. “Common tendon overuse injuries or muscle strains recover well with rest and perhaps a few visits to the physiotherapist. But, when things go really wrong, you may find yourself in an orthopaedic surgeon’s office with one or more of the three most common injuries.”
Whether you play sports or not, here are details of three knee injuries that can land you in an orthopaedic surgeon’s office.
#1 Meniscus tear
Though playing contact sports will surely put you at a higher risk of tearing your meniscus – the thin, fibrous tissue that provides cushioning between your thighbone and shinbone – you certainly don’t have to be an athlete to experience this type of injury; all it takes is a sudden twist, or getting up from a squat the wrong way.
“Imagine a bicycle helmet with the inner ring that sits on your head. That ring, when fitted well, dissipates the force of an impact on the helmet and protects your head from injury. That is your meniscus. It is a shock-absorbing cushion that is shaped like a ring and protects the bones and cartilage in your knee from sustaining too much damage with day-to-day activities such as walking, running or jumping,” says Dr Lee.
Symptoms of a torn meniscus may include knee pain, swelling, a popping sensation, difficulty straightening the knee, and a locked knee feeling. However, in some cases, there may not be any symptoms at all.
According to Dr Lee, meniscal tears do not heal well, and only certain types can be surgically repaired – done by stitching together the repairable tears and letting one’s body heal the torn areas. “Irreparable tears that cause symptoms of pain or restricted movement in the knee may need to be trimmed and discarded,” he says. “It usually takes around six months of physiotherapy after meniscal repair to get back to sports. Surgery is only indicated if the patient develops symptoms that do not resolve.”
#2 Articular cartilage injury
While a meniscal tear is a more common injury in the knee, the smooth tissue that cushions the ends of the bones, called articular cartilage, can be damaged, too.
“Think of a silk Persian rug – soft and smooth. Now, picture a big hole in that rug; that’s your smooth cartilage overlying the bones in your knee joint with a hole in it. Suddenly, your knee doesn’t move so smoothly anymore, and the bone underneath it starts to hurt,” says Dr Lee. “Cartilage injury in the knee may cause the knee to swell or click. The knee may also lock up and have restricted movement. If the damage is bad, the exposed, underlying bone may also start to hurt.” However, he says in many cases there are no symptoms at all.
Because cartilage doesn’t have a blood supply like other types of tissue, it doesn’t heal when damaged. “When the injury is very symptomatic and the symptoms do not resolve, surgery can sometimes help to try to restore cartilage to the damaged area,” says Dr Lee. “It may take six to 12 months to recover after surgery.”
“One way to patch the hole is to cut a corner of your ‘rug’ and to use that piece to fill the defect,” says Dr Lee. “Alternatively, you can cut a piece of your remaining rug and send it to a factory to see if matching material can be made to patch the rug. This expensive, two-staged procedure involves harvesting some of your native cartilage, sending it to a lab overseas to grow for a few weeks, then implanting that newly grown cartilage into your knee’s cartilage defect.”
Dr Lee says that the simplest option, however, is a procedure called ‘microfracture’, where small holes are drilled into the bone under the missing cartilage, allowing for a blood clot to form. “Over time, this clot remodels, eventually creating replacement cartilage; however, this replacement cartilage does not have the full characteristics and function as the original cartilage.”
#3 ACL tear
Bones are connected to other bones by ligaments – short bands of tough connective tissue. As one of the four main ligaments that stabilise the knee, the anterior cruciate ligament (ACL) is very commonly torn during sporting activities that involve tackling, jumping, stopping suddenly or quickly changing direction. Typical symptoms of this type of knee injury include pain, a popping sound during injury, knee instability and swelling.
Dr Lee says that ACL reconstruction is the standard surgical procedure for a symptomatic ACL-deficient knee. “During surgery, a tendon graft is used to replace the torn ligament. This graft can sometimes be taken from a deceased donor, but more commonly, it is taken from your own hamstrings or kneecap tendon,” he says. “The most common graft used in Singapore is a hamstring graft, where two tendons are taken from the inner thigh to replace your ACL. Newer techniques such as the All-Inside ACL reconstruction only require the sacrifice of one tendon instead of two, thus preserving the original function of the second tendon.”
He adds that newer surgical techniques have also made it possible to repair certain types of ACL tears with good outcomes and faster rehabilitation. As for recovery time, Dr Lee says that it normally takes at least nine to 12 months of physiotherapy and rehabilitation to get a patient back to playing sports.
“The good news is that surgery is not always required,” says Dr Lee. “Without an ACL, you can also still do ‘in-line’ sports such as jogging, cycling and swimming. Some individuals may even be able to return to light tennis or football with adequate physiotherapy.” However, he notes, “Every individual’s body condition and expectations are different. It is therefore important that you have a good evaluation and discussion with your doctor before deciding on how to proceed. Despite the injuries, you can still come out a winner with appropriate treatment.”
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