Acute injuries affecting the knee joint cause considerable disability and time off sport. They are common in all sports that require twisting movements and sudden changes of direction, especially the various football codes, basketball, netball and alpine skiing.
Meniscal Injuries
Acute meniscal tears occur when the shear stress generated within the knee in flexion and compression combined with femoral rotation exceeds the meniscal collagens ability to resist these forces. The medial meniscal attachment to the medial joint capsule decreases its mobility, thereby increasing its risk for injury compared with the more mobility. Degenerative meniscal tears occur in the older population frequently without an inciting event.
Clinical Features
The history can provide a mechanism and a sense of the severity of meniscal tears. The clinical features are listed below.
- The most common mechanism of meniscal injury is a twisting injury with the foot anchored on the ground, often by another player’s body.
- The twisting component may be of comparatively slow speed. This type of injury is commonly seen in football and basketball players.
- The degree of pain associated with an acute meniscal injury varies considerably. Some patients may describe a tearing sensation at the time of injury.
- A small meniscal tear may cause no immediate symptoms; it may become painful and cause knee swelling over 24 hours.
- Small tears may also occur with minimal trauma in the older athlete as a result of degenerative change of the meniscus.
- Patients with more severe meniscal injuries, for example, a longitudinal (bucket handle) tear, present with more severe symptoms. Pain and restriction of range of motion occur soon after injury. Intermittent locking may occur as a result of the torn flap, the (bucket handle )impinging between the articular surfaces. This may unlock spontaneously with a clicking sensation. This often occurs in association with ACL tears. In these patients a history of locking may be due to either the ACL or the meniscal injury.
Treatment
The management of meniscal tears varies depending on the severity of the condition.
- At one end of the spectrum, a small tear or a degenerative meniscus should initially be treated conservatively.
- On the other hand, a large painful (bucket handle )tear, causing a locked knee, requires immediate arthroscopic surgery.
- The majority of meniscal injuries fall somewhere between these two extremes and the decision on whether to proceed immediately to arthroscopy must be made on the basis of the severity of the symptoms and signs, as well as the demands of the athlete.
- The aim of surgery is to preserve as much of the meniscus as possible. Some meniscal lesions are suitable for repair by meniscalsuture, which can be performed with an arthroscope.
- The decision as to whether or not to attempt meniscal repair is based on several factors, including acuity of the tear, age of the patient, stability of the knee, and tear location and orientation.
- The outer one-third of the meniscus rim has a blood supply, and tears in this region can heal.
- The tear with the best chance of a successful repair is an acute longitudinal tear in the peripheral one-third of the meniscus in a young patient with a concomitant ACL reconstruction.
- Degenerative, flap, horizontal cleavages and complex meniscal tears are poor candidates for repair. Young patients have a higher success rate.
- Peripheral meniscus tears in otherwise stable knees without concomitant ligament damage have a reduced success rate.
- Partial tears may require removal of the damaged flap of the meniscus. Patients with degenerative tears with no or minimal cartilage wear will be less symptomatic than those patients with concomitant cartilage damage.
Rehabilitation After Meniscal Surgery
Rehabilitation should commence prior to surgery. In this period it is important to:
- Reduce pain and swelling with the use of electrotherapeutic modalities and gentle range of motion exercises.
- Maintain strength of the quadriceps, hamstrings, and hip abductor and extensor muscles.
- Protect against further damage to the joint (patient may use crutches if necessary).
- Explain the surgical procedure and the post operative rehabilitation program to the patient.
- The precise nature of the rehabilitation process will depend on the extent of the injury and the surgery performed.
- Arthroscopic partial menisectomy is usually a straightforward procedure followed by a fairly rapid return to activity.
- Some athletes with a small isolated medial meniscal tear are ready to return to sport after four weeks of rehabilitation.
- The rehabilitation process usually takes longer if there has been a more complicated tear of the meniscus, especially if the lateral meniscus is injured. The presence of associated abnormalities, such as articular cartilage damage or ligament (MCL, ACL) tears, will necessarily slow down the rehabilitation process.
- If the athlete returns to play before the knee is properly rehabilitated, he or she may not experience difficulty during the first competition but may be prone to develop recurrent effusions and persistent pain.
- A successful return to sport after meniscal knee surgery should not be measured by the time to play the first match but rather the time to play the second.
Rehabilitation Principles after Arthroscopic Partial Menisectomy are:
- To control pain and swelling
- To regain pain-free active range of motion
- Graduated weight-bearing
- Progressive strengthening within the available range of motion
- Progressive balance, proprioceptive, and coordination exercises
- Return to functional activities.
A typical rehabilitation program following arthroscopic partial menisectomy. The suggested rehabilitation program may be varied depending on progress. Every patient is different and will differ in his or her response to injury, surgery and rehabilitation. Close monitoring is essential during post-menisectomy rehabilitation as the remaining meniscus and underlying articular cartilage slowly increase their tolerance to weight-bearing. Constant reassessment after progressively more difficult activities should be performed by the therapist monitoring the rehabilitation program. The development of increased pain or swelling should result in the program being slowed or revised accordingly.
Conservative Management of Meniscal Injuries
Conservative management of relatively minor meniscal injuries will often be successful, particularly in the athlete whose sporting activity does not involve twisting activities. The principles of conservative management are the same as those following partial menisectomy, although the rate of progress may vary depending on the clinical features.
The criteria for return to sport following meniscal injury, treated surgically or conservatively, are shown below. If appropriate rehabilitation principles have been followed, then the criteria will usually all be satisfied:
- Absence of effusion.
- Full range of movement.
- Normal quadriceps and hamstring function.
- Normal hip external rotator function good proprioception.
- Functional exercises performed without difficulty.
- Training performed without subsequent knee symptoms.
- Stimulated match situations undertaken without subsequent knee symptoms.
