‘Locking knee’ is a fairly common
complaint by athletes who have twisted their knees in sports like
basketball, netball, soccer or badminton or an awkward fall. This experience of ‘knee locking’ is an indication of a
possible meniscus tear.
Our knee meniscus, which is a moon-crescent shaped cartilage located between the knee, acts as a shock cushion to absorb the impact between the leg and thigh bone.
Our meniscus is better at the handling loads/forces from a vertical motion (up and down) due to the way it's shaped.
Unfortunately, our meniscus is susceptible to a twisting injury ESPECIALLY when it's compressed AND twisted, can cause a tear in the meniscus. The "locking" happens when the torn part of the meniscus blocks the movement of the knee.
Normally immediately after meniscus injury, there will be immediate:
- in the knee. But sometimes there are delays in the onset of swelling or weirdly, sometimes there is no swelling at all (depending on the severity and location of the meniscal partial tear).
Please do remember how you injured you knee as it'd help your doctor or knee physiotherapist in diagnosing and treating this problem.
Differential diagnosis is necessary to exclude injuries that may cause the same symptoms as MCL injury of the knee.
These injuries are:
A physical examination will help to ensure a correct diagnosis. A medial meniscal tear can be mistaken for an MCL sprain, because the tear causes joint tenderness like the sprain. With a valgus laxity examination a medial meniscal tear can be differentiated from a grade 2 or 3 MCL sprain.
The presence of an opening on the joint line means the medial meniscus is torn. A grade 1 MCL is more difficult to differentiate from a medial meniscal tear.
The differentiation can be made through an MRI or by observing the patient during several weeks. In case of an MCL sprain tenderness usually resolves, with a meniscal injury it persists.
When there is tenderness, but no abnormal valgus laxity, it could be a case of medial knee contusion. If the tenderness is situated near the adductor tubercle or medial retinaculum adjacent to the patella, the cause is more likely to be patellar dislocation or subluxation.
Patellar instability can be differentiated from an MCL sprain with the
patellar apprehension test. A positive result means there is patellar
The treatment of a medial collateral ligament injury rarely requires a surgical intervention. The extracapsular, the medial collateral ligament, appear to have a fairly robust potential to healing (level 1A).
In cases where instability excist after nonoperative treatment, or instances of persistent instability after ACL and/or PCL reconstruction, the MCL tear may be addresses through surgical repair or reconstruction (level 1A).
The most isolated MCL injuries are successfully treated non-operatively with bracing or immobilization. Some simple treatment steps, together with rehabilitation, will allow patients to return to their previous level of activity.
The most treatment protocols focusing on early
range of motion, reducing swelling, protected weight bearing,
progression toward strengthening and stability exercises. The general
goal is to have an athlete or patient return to full activities (level
The overall rehabilitation principles are (level 1A):
We can divide a medial knee injury in three grades. Level of evidence: 1a
The treatment for isolated grade 1 injuries is mainly non-operative.
During the first 48 hours, ice, compression and elevation should be used as much as possible. In general, incomplete tears of the MCL are treated with temporary immobilization and use of crutches for pain control.
Isometric, isotonic and eventually isokinetic progressive resistive
excercises are begun within a few days of the subsidence of pain and
swelling. Weight-bearing is encouraged, the rate being dictated by the
level of pain. Level of evidence: 1a .
Grade 2 / 3
For a grade 2/3 injury-treatment it is important that the ends of the ligament are protected and left to heal without continually being disrupted. One should avoid applying significant stresses to the healing structures until three to four weeks after the injury to ensure that the injury can heal properly.
The treatment for grade 3 injuries depends on whether the injury is isolated or combined with other ligamentous injuries (level 1A).
For a grade 3 medial knee injury combined with an another injury for example an ACL tear, the general protocol is the rehabilitation of the medial knee injury first so it can allow to heal according to the guidelines for an isolated medial knee injury.
When there is good clinical and/or objective evidence of healing of the medial knee injury, mostly 5 to 7 weeks after the injury, the reconstruction of the ACL can begin. Level of evidence: 1a.
Rehabilitation for a non-operative treatment can be split into four phases:
Phase One is from one to two weeks.
Phase one consists of controlling the swelling of the knee by applying ice (cold therapy) for 15 minutes every two hours (first two days). The rest of the week the frequency can be reduced to three times a day. Use ice as tolerated and as needed based on symptoms.
In the begin the patient need to use crutches. Early weight bearing is encouraged because patients who increasing their weight bearing, they can progressively reduce their dependence on crutches. Afterwards progress to one crutch and let the patient stop using the crutches only when normal gait is possible.
Another aim of this phase is trying to maintain the ability to straighten and bend the knee from 0° to 90° knee flexion. For achieving the range of motion of the knee it is important to emphasize full extension and progress flexion as tolerated.
Pain free stretches for the hamstrings, quads, groin and calf muscles (in particular) are suggested.
At last there are the therapeutic exercises. The patient may begin with static strengthening exercises (as soon as pain allows it).
They consist for example of
As soon as patients can tolerate it, they are encouraged to ride a stationary bike to improve the range of motion of the knee. This would ensure an accelerated healing.
The amount of time and effort on the stationary bike is increased as tolerated. Obviously, every patient is different and these are not the standard exercises that has to be given to patients.
There are no limits on upper extremity workouts that do not affect the injured knee (level 1A). It’s important that the patient rests from all painful activities (use crutches if necessary), and that the MCL is well protected (by wearing a stabilized knee brace).
Starting at week three phase two begins.
The aims for the range of motion are the same as in phase one.
Progress to 20 minutes of biking. Increase also the resistance as tolerated by the patient. Biking will ensure the healing, rebuild strength and maintain the aerobic conditioning.
The physiotherapist can give other exercises like
As precaution the patient has the chance to be examined by a physician every three weeks to verify the healing of the ligament (level 1A).
Phase three starts from week five.
Major goal for this phase: full weight-bearing on the injured knee. Discontinue the use of a brace when ambulating with full weight bearing is possible and there is no gait deviation. The range of motion has to be fully achieved and had to be symmetrical with the not injured knee.
The therapeutic exercises are the same as in phase two.
They may benefit progression. We continue with cold therapy and compression to eliminate swelling. In this phase you can commence with balance and proprioceptive activities.
To maintain aerobic fitness the patient can use the stepper or (if possible) may begin to swim. As precaution the patient has the chance to be examined by a physician every five to six weeks. When needed, you can be allowed to make stress radiography as precaution (level 1A).
Six weeks after injuring the knee, phase four can begin.
Discontinue wearing the brace during the gait.
Athletics can wear the brace for competition through competitive season for at least three months. Cold therapy still needs to be applied. The aim of the therapeutic exercises is more focused on sport specific or daily movements.
The intensity of the strengthening exercises need to be increased and instead of double leg exercises we change to single leg exercises. The patient may start running again at a comfortable pace (make sure the patient doesn’t make sudden changes of direction).
As precaution it is best to return the competition once full motion and strength is returned and when the patient passes a sport functional test (level 1A). Obviously, every patient is different so the application of these principles should be guided by the overall rehabilitation principles (level 1A)
Applying cold therapy reduces swelling immediately after injuring and doesn’t help the healing process of the ligament (level 1A).