Spontaneous injuries and degenerative ‘wear and tear’ can be caused in the knee for a number of reasons. Whether it is through acute accidents, sporting injuries, or overuse of the knee in occupational demands, there are many structures within the knee that are susceptible to damage. Our Head of Orthpaedic Physiotherapy, Zoe Birch, explains the most common injuries affecting the knee and how they are diagnosed and treated.
The meniscus is a spongy material in the knee held between the thigh and shinbones. It is often seen as the ‘shock absorber’ of the knee, but this is not necessarily true. Research shows that it doesn’t necessarily take the impact of the knee, but disperses the load and stress around the surface of the knee. Its main role consists of reducing the resistance of the knee when bending and also providing stability and congruency to the knee joint.
A twisting motion in the knee typically damages the meniscus, although it can become affected by degenerative changes (i.e. osteoarthritis). The textbook presentation of a meniscus injury is tenderness over the knee joint line on palpation, occasional painful clicking or locking of the knee and discomfort when twisting on the knee. There are many types of tears to the meniscus with some more severe than others.
Individuals can have some minor meniscus damage and tearing without it necessarily being painful. A significant amount of professional footballers would present with meniscus damage on MRI scans of their knee, but this doesn’t necessarily have to be medically managed. If there is a symptomatic presentation of this damage, which is confirmed by a MRI scan, then your orthopaedic surgeon may opt for an arthroscopic procedure on the knee in order to debride the damaged portion of the knee.
The conservative physiotherapy management would consist of increasing the stability and movement patterns of the knee by correcting muscle imbalances. These exercises could also be combined with steroid injections in order to manage the pain and swelling associated with this injury.
Collateral Ligament Injury
A large impact onto the outside of the knee can cause damage to the ligaments, which run on the inside of the leg (and vice versa). The collateral ligaments are bands of tissues that attach on the outside and inside of the thigh and shinbones to add stability to the knee. These ligaments can become stretched or even fully ruptured.
The presentation which will point towards this diagnosis is instability on a lateral stress test, pain on palpation along the inside/outside of the knee and a feeling on instability when walking/turning on the knee. Watch this short video to see how physios complete a lateral stress test:
The typical impact which causes a collateral ligament injury is heavy and occurs to the outside of the leg, or whilst slipping or falling onto the side of the knee. Depending on the extent of the injury, this instability will be more pronounced.
Minor strains to this ligament will follow the usual recovery pattern presenting with some minor instability, pain and swelling until the healing process is complete. This may not need physiotherapy input in order to recover. If there is the need for surgical requirement, the standard management of strengthening, flexibility and stability rehabilitation will be implemented.
Cruciate Ligament Injury
The cruciate ligaments are the two strong bands inside the knee, which provide stability at the front, anterior, and the back, posterior, of the knee. These are most commonly damaged during sporting events. The typical Anterior Cruciate Ligament tear happens in a movement pattern in which the knee is internally rotated and twisted. This is known as a ‘dynamic valgus’. A textbook example of this movement can be seen when Michael Owen tore his ACL whilst playing football for England against Sweden in 2006. Typically, the knee will instantly balloon with swelling due to the cruciate ligaments being very highly perfused – this is known as haemarthrosis or “bleeding into the joint”.
The typical test that identifies a ligament laxity or ‘loose ligaments’ is a pull on the calf. Sometimes this test can be a false-negative, showing that the knee has no distinct laxity despite a full tear of the ligament. Some individuals with this false-negative result can still perform their normal sporting activity with a torn cruciate ligament. They are known as ‘Cruciate deficient’. Cruciate deficient individuals with strong quadriceps and hamstrings will be able to ‘cope’ by still having the stability required in the knee to be able to walk and run without problems.
Physiotherapy rehab will focus on restoring correct movement patterns in the knee in order to prevent further injury. Following this injury, the individuals will often present with reduced confidence in the knee and possible instability when squatting and twisting.
Combination of Injuries
It is possible to damage a combination of the structures within the knee from the same injury. Particular combinations of these injuries are defined in certain ways, for example the “Unhappy Triad of O’Donoghue” as its known in medical circles consists of a medial collateral ligament tear, a medial meniscus tear as well as an ACL Rupture.
If you have had any of these injuries or surgeries in order to rectify these injuries, you will most probably already be well known to a physiotherapist. It is important to have a good rehabilitation program in order to restore normal functional movement, gait and provide the best chance in returning to your previous sporting level.
Post by Zoe Birch, Head of Orthopaedic Physiotherapy at Physiocomestoyou.