The ‘Need-to-Know’ on Knee Injuries. What injuries cause the most prolonged absence from sport and how to know when to return?
The knee joint is formed by the thigh bone (femur) and shin bone (tibia). Your kneecap, or patella, sits in a groove on your femur and this joint is know as you patellofemoral joint. The main movements that your knee performs is bending (knee flexion) or straightening (extension). There are four main ligaments that help restrict unwanted movements at your knee: the anterior and posterior cruciate ligaments, the medial ligament which is on the inside, and lateral ligament which is on the outside.
The major structure that when injured causes the most prolonged absence from sport is the ACL, which stops the tibia moving forward on the femur as well as rotation. Commonly it is injured when pivoting or landing and it is accompanied by a loud ‘pop.’ Typically you are unable to continue the activity due to the knee giving way and pain. This is usually followed by swelling. If the ACL has ruptured, you will more than likely require a knee reconstruction. Diagnosis of such an injury is able to be made by your physiotherapist but may also require an orthopaedic surgeon to assess the knee and possibly investigations such as a magnetic resonance imaging (MRI) scan to confirm the diagnosis and to assess for other coexisting pathologies..
The most common type of reconstruction performed uses your hamstring tendon as the graft for the new ligament. The surgeon may elect to use another method such as your patella tendon, or even a synthetic graft. In the reconstruction, the surgeon will take a portion of your hamstring tendon and insert it to take the place of your ACL. This is all done by arthroscope and physiotherapy will generally start within the first week. Over the course of the next nine to twelve months, a rehabilitation program will be followed which is set out by the orthopaedic surgeon in consultation with your physiotherapist. After such surgery and a comprehensive rehab program, you can reduce the risk of injury to almost the same risk of injury as you had before your initial injury.
But at the end of your rehabilitation, how do you know when you right to return to sport? Below are a series of hop tests which can help you and your physiotherapist decide when you are right to return.
Studies have shown that 3 simple tests: vertical jump, hop for distance and a side hop can accurately show when your knee is right for action. Your injured side must be at least 90% of your un-injured leg in all tests to pass. The tests look at the strength of the muscles surrounding your knee, the ability to control your knee under high load as well as its resistance to fatigue. It is important that these tests are done under appropriate supervision of your physiotherapist.
Start by standing upright on your un-injured leg with your arm up as high as possible with chalk bend your knee and jump as high as possible while striking the wall with your hand at the highest point. Repeat with your injured side.
Hop for Distance
Stand on your uninjured leg with hands behind your back, bend your knee and hop as far as possible. You must be able to hold the landing for 3 seconds. Measure from your toe at push off and the heel where you landed. Repeat with your injured leg and compare the two scores.
Get two strips of tape 40cm apart on the floor. Stand on your un-injured leg and hop from side to side without touching the tape as many times as you can in 30 seconds. Repeat the test with your injured side and compare the two results.
The results of these tests will let you know what elements you need to work on: strength, stability or fatigue. These tests should be completed under appropriate supervision and it is also important that if you have had a reconstruction, before you return to sport, you are cleared by your orthopaedic surgeon.
To make an appointment with one of our Physiotherapy team to discuss your keen pain or when to return to sport book online, email email@example.com or call 07 3891 2000.