- 1 Definition/Description
- 2 Clinically Relevant Anatomy
- 3 Epidemiology
- 4 Indication for Procedure
- 5 Differential Diagnosis
- 6 Clinical Presentation
- 7 Diagnostic Tests
- 8 Outcome Measures
- 9 Medical Management
- 10 Physical Therapy Management
- 11 Key Research
- 12 Resources
- 13 References
A meniscal repair is a surgical procedure to repair a torn meniscus via keyhole surgery. It is a minimally invasive procedure often undergone as an outpatient. Factors affecting success include tear age, location and pattern, age of the patient, as well as any associated injuries.
Clinically Relevant Anatomy
The major meniscal functions are to distribute stress across the knee during weight bearing, provide shock absorption, serve as secondary joint stabilizers (in an anterior cruciate ligament deficient knee, menisci will serve as joint stabilizers  , provide articular cartilage nutrition and lubrication, facilitate joint gliding, prevent hyperextension, and protect the joint margins.
During knee flexion, the femoral condyles glide posteriorly on the tibial plateau in conjunction with tibial internal rotation. The lateral meniscus undergoes twice the anteroposterior translation of the medial meniscus during knee flexion. This translation prevents the femur from contacting the posterior margin of the tibial plateau.
The meniscus is divided into three zones: the red-red, the red-white and the white-white. The zones are divided by vascularization and thus healing potential.The red-red zone is the peripheral zone of the meniscus. It is very good vascularized and has a good healing rate. Patients differ in vascularization of the medial and lateral meniscus, varying between 20-30 and 10-25 % width. The red-white zone is the middle third with less vascularization but can though heel sometimes. The white-white zone has no blood capillaries at all and therefore cannot heal.
Meniscal lesions are the most common intra-articular knee injury in the United States and are the most frequent cause of surgical procedures performed by orthopaedic surgeons. The mean annual incidence of meniscal lesions is 0.066 %.  There are more male patients (59,5%) undergoing an isolated meniscal repair compared with female patients (40,5%). This is the same compared with male patients (60%) undergoing a concomitant meniscal repair and anterior cruciate ligament. So most of the patients undergoing meniscal repair are males. 
In general, meniscal tears frequently occur in middle-aged and elderly patients and are caused by long term degeneration.
One third of the lesions by young patients are caused by sports-related injuries, because of the cutting or twisting movements, hyperextension or actions with great force. In more than 80%, meniscus tears are accompanied by anterior cruciate ligament (ACL) injury.
Meniscal lesions in children are different than those in adult patients. In children, more than 70 percent are isolated meniscal lesions caused more of the time by sport-related twisting of the knee. 
Indication for Procedure
Indication for procedure
Nonoperative treatment is rarely successful for treating meniscal tears in young athletes and repair of the torn menisci is often required
Repair of a meniscal lesion should be strongly considered if the tear is peripheral and longitudinal, with concurrent Anterior Cruciate Ligament (ACL) reconstruction, and in younger patients. The probability of healing is decreased in complex or degenerative tears, central tears, and tears in unstable knees. Numerous repair techniques are available.
Preservation of meniscal tissue is recommended, regardless of age - in active patients- whenever possible.
Meniscal tears amenable to repair include unstable tears > 1 cm in length and occurring in the outer 20% to 30% toward the periphery, or in the so-called red-red zone. Those tears occurring more toward the junction of the red-white zone may also heal, and the decision to repair should be made based on the clinician's judgment. Ideal candidates for repair are vertical, longitudinal tears occurring within 3 mm of the peripheral rim.
Indication for surgery
The decision whether a lesion is treated surgically or non-surgically is the first decision made after definitively diagnosing a meniscal tear. This decision is based on patients factors (e.g. age, co-morbidities and compliance), tear characteristics (e.g. location of the tear, age of the tear and pattern of the tear) and the fact whether the tear is stable or unstable. When the tear is unstable surgery is necessary.>
A degenerative tear or a non-degenerative tear which is asymptomatic or stable is treated non-surgically. In the other cases, such as non-degenerative tears or tears which are symptomatic the tears are treated surgically. 
The second decision concerns whether meniscal repair or meniscectomy is appropriate. If none of the normal surgical treatments seems appropriate total meniscectomy is the last option. The factors that should have been taken in consideration while making decisions should be: 1) the clinical evaluation, 2) related lesions and 3) the exact type, location, and extent of the meniscal tear. 
If meniscal repair is performed combined with an ACL reconstruction the success rate is influenced. Whether the influence is positive or negative is studied in several studies with different conclusions.    
Tenuta JJ et al. also found that width of the lesion is an important factor no lesion with a width of more than 4 mm healed.
• Joint line tenderness and effusion. However the joint line tenderness test may be false positive with osteoarthritis, osteochondral defects, collateral ligament injury or fractures. 
Effusion may also occur when there are problems with the cruciate ligaments, bones or the articular cartilage.
• Symptoms are frequently worsened by flexing and loading the knee, activities such as squatting and kneeling are poorly tolerated. But it’s the same with patients suffering from other pathologies like chondromalacia patellae, fractures and Sinding Larsen Johansson Syndrome.
• Complaints of 'clicking', 'locking' and 'giving way' are common. Patients also complain about ‘giving’ way when there are suffering from anterior cruciate ligament injury. The feeling of instability and locking is also common with osteochondritis dessecans.
- Joint line tenderness and effusion.
- symptoms are frequently worsened by flexing and loading the knee, activities such as squatting and kneeling are poorly tolerated.
- complaints of 'clicking', 'locking' and 'giving way' are common
When making a diagnosis, relevant patient history, physical examination, and appropriate imaging studies are required.
- Joint line tenderness has been reported to be the best common test for meniscal injury.
- McMurray's test positive if a pop or a snap at the joint line occurs while flexing and rotating the patient's knee.
- Apley's test performed with the patient prone, and with the examiner hyperflexing the knee and rotating the tibial plateau on the condyles.
- Steinman's test performed on a supine patient by bringing the knee into flexion and rotating.
- Ege's Test is performed with the patient squatting, an audible and palpable click is heard/felt over the area of the meniscus tear. The patient's feet are turned outwards to detect a medial meniscus tear, and turned inwards to detect a lateral meniscus tear.
- Meniscal Imaging is an essential tool in decision making for surgical management of meniscus tears. Accurate imaging of the meniscus is essential to evaluate the damaged area and to select the most appropriate treatment. Imaging is also an important tool for postoperative management and treatment, follow up and identification of any further injury. Currently, magnetic resonance imaging (MRI Scans) is the preferred imaging technique. Other techniques are Radiography, Computed Tomography (CT Scans) scan, Computed Tomography (CT) arthrography and Magnetic Resonance Arthrography. 
The advantages of MRI in the diagnosis of a meniscus lesion are: grade-I and grade-II tears are detected earlier, extra-articular structures are also visible, no radiation and MRI is a non-invasive imaging technique. 
An overall meniscal repair success rate of 85-90% has been found by R.P.Walter et al. 
Patients undergoing con concomitant anterior cruciate ligament reconstruction enjoyed significantly improved outcomes of meniscal repair. (91%), while those with a past history of anterior cruciate ligament reconstruction had significantly worse meniscal repair success rate (63%). Bohnsack found a healing rate of 86-95%. The overall success rate for healing menisci with meniscal repair is high.
In most of the studies they took a second MRI to confirm whether the lesion is healed. A patient is considered as being healed when there is no lesion on the second MRI and the patient is able to resume his normal life/activities.
Locked bucket-handle, meniscal tears heal at a high rate when repaired as an isolated surgery; even when full weight bearing and activity before reconstruction is allowed and when the tear is in the white-on-white zone.
Age or time between injury and surgery don’t affect the amount of people that were healed by meniscal repair.
Indication for surgery are complete or large incomplete longitudinal tear of the media and lateral meniscus close to the base, large flap tear, so-called bucked-handle tear. 
Degenerative meniscal tissue. Unstable knee joint without concomitant surgical stabilization. Complex meniscal tears or radial tears, tear in the central avascular region, gonoarthrosis, joint infection and local skin disorders. 
Meniscal repairs can be performed by open, inside-out, outside-in and all-inside techniques. But not all meniscus tears have the ability to heal, the meniscal tear pattern and the presence of adequate vascularity are both key. 
When meniscus repair is carried out under arthroscopic visualization, in the same manner as the inside-out, the outside-in and the all-inside technique, some common steps, which are independent of the technique, have to be followed. There have to be arthroscopic set-up, tear debridement and fixation. 
This technique offers the advantage of better preparation of the tear side. However, only the most peripheral of tears in the red-red zone are amenable to this technique and the main disadvantage of this technique is the risk of neural damage. Nowadays this technique isn’t frequently used anymore.
The capsule is incised posterior to the collateral ligament and the synovium is opened to give direct access to the posterior segment of the meniscus and the tear, provided that it is a vertical peripheral longitudinal tear. In case of a horizontal tear, the meniscosynovial rim needs to be dissected in order to expose the peripheral meniscal rim and the horizontal cleavage.  
Absorbable or nonabsorbable 2-0 or 0 sutures are passed from inside the knee to a protected area on the outside of the joint capsule, using long flexible needles. The sutures are retrieved through an extra-articular posteromedial or posterolateral incision. The posterior neurovascular structures are protected with a large retractor. The knots are tied outside the joint over the capsule.  
This technique has been considered the gold standard in meniscus repair because of the proven long term results, but there is still a risk of neurovascular complications.   
A cannulated 18-gauge spinal needle is passed across the tear from the outside-in. Once the sharp tip of the needle is in view, the suture is passed through the arthroscopic ipsilateral portal. An interference knot is tied in the end of the suture and the suture is pulled back. The process is repeated and the free ends are tied two by two over the capsule through an accessory skin incision until the tear is stabilised. Sutures may be placed alternately on the femoral and tibial surface of the meniscus in order to balance the repair. 
This technique can be used for repairing extreme posterior horn tears. All-inside repairs have been traditionally carried out using several devices, such as staples, tacks and screws. Most of these devices are bioabsorbable and composed of rigid poly-L-lactic acid (PLLA). 
  
The newest devices are the self-adjusting suture devices. They are based on the same principle as the other devices. An anchor is positioned behind the capsule and a suture compresses and holds the axial meniscal part by using a sliding knot. These implants share the potential ability to deform and move with the meniscus during weight bearing and carry a lower risk of chondral abrasion. The devices are RapidLoc, FasT-Fix and the Meniscal Cinch. 
The advantages of all-inside repair include ease of use, avoidance of an accessory incision, shorter operation time, less risk to neurovascular structures and especially for the suture devices better strength. 
Small  et al. studied the complications of 10,262 patients undergoing meniscal repair. Of the 10,262 patients 1,68% had complications. These complications were: Hemarthrosis, infection, thromboembolic disease, anesthetic complications, instrument failure, reflex sympathetic dystrophy, ligament injury, fracture and neurologic injuries. With hemarthrosis being the most common complication and neurologic injuries being least common. No vascular injuries were reported. And there was emphasized 7% incidence of saphenous neuropathy by Austin et al.
Physical Therapy Management
During the pre-operative phase of total knee replacement and anterior cruciate ligament reconstruction, it is proven that quadriceps strength training leads to improved knee function and a better quality of life after the operation. (LoE:1B) (LoE:1) (LoE:4)
It is also proven that neuromuscular electrical stimulation improves quadriceps muscle strength in subjects with Knee Osteoarthritis Most patients who choose for meniscal repair are operated within a short period of time, because of that there is seldom pre-operative physical therapy. But if a quick operative intervention is not possible for any reason, we assume that quadriceps training is also beneficial for patients undergoing meniscal repair.
The use of electromyographique biofeedback in the early stages of rehabilitation, after meniscal repair helps patients to control their muscles. It can help accomplish physical activities that require better neuromuscular coordination and control. For these reasons one may consider elektromyographique biofeedback as an important component of rehabilitation after meniscal repair. Electromyographique Biofeedback is not responsible for the degrees in pain, swelling or other post-operative symptoms. This technique is a painless, non-invasive method that can be used in muscle recovery. This technique can be used in all phases of the rehabilitation.(Level of Evidence: 3A) 
The type of surgery employed is largely dependent on the type of tear and its location. The most common surgical lesion in the knee is a torn meniscus.(Level of Evidence: 3B) (Level of Evidence: 3B) The goal of the surgery is to save as much as possible healthy tissue.(Level of Evidence: 2A)
At long term the surgical repair of the meniscus gives a better result than a partial meniscectomy. But the revalidation is longer.(Level of Evidence: 4) This is something that the athlete must choose whether he wants to resume the sport quickly or not.
There are 4 types of surgical repair: open, inside-out, outside-in and all-inside.
For each operation they have to remove the loose parts, both surfaces of the tear should be sanded and the vascularity should be encouraged.
The all-inside techniques are attractive because of the decrease in operative time and ease of the technique. Short-term results are positive for the all-inside technique; however, good long-term data on these techniques are lacking.
Patients who have repairs of peripheral meniscus tears are generally progressed more rapidly than those who have repairs of tears extending in the central one-third region or those who undergo meniscal transplantation. (Level of Evidence:2A)
The advantage of meniscectomy is that only the damaged tissue is removed. Important is that the circular collagen fibers may not be cut. (Level of Evidence: 2B) When that happens, the meniscus will lose his function as distributor of weight and then there is an increased risk of Osteoarthritis.
A disadvantage of meniscectomy is that there is a prolonged conservative aftercare. There needs to be a period of maximum prognose to obtain the best possible healing.
Patients who have had an arthroscopic partial meniscectomy often initially experience knee swelling, pain, and loss of range of motion (ROM), and they may have increased joint laxity and osteoarthritis in the long term. 
Meniscal injuries are often accompanied by injuries to the anterior cruciate ligament, the collateral ligaments or the joint cartilage.  Such associated injuries also influence functional recovery after an arthroscopic meniscectomy.(Level of Evidence: 3A) 
Supervised rehabilitation after surgery has been advocated and studied as part of short- and long-term follow-up after arthroscopic partial meniscectomy. 
The goal of rehabilitation is to restore patient’s function based on individual needs. It is important to consider the type of surgical procedure, which meniscus was repaired, the presence of coexisting knee pathology (particularly ligamentous laxity or articular cartilage degeneration), the type of Meniscus rupture, the patient's age, preoperative knee status (including time between injury and surgery), decreased range of motion or strength, and the patient's athletic expectations and motivations. 
Exercise has been suggested to be an efficient treatment for patients with knee degeneration in order to improve knee function and limit joint pain. There is strong evidence that physical training plays an important role in order to reduce symptoms, improve muscle strength and physical ability.
Important points in the therapy:
• control the pain and inflammation - Cryotherapy, analgaesics, NSAIDs,
• To regain good knee control 
• restore ROM (Range of motion) - ROM exercises within any limits in range that the consultant has requested 
• Restore the flexibility 
• restore muscle function - specific strengthening exercises including quadriceps (A medial meniscus lesion influences the strength of the M. Vastus medialis.), hamstrings, calf, hip
The exercise program should consist of both concentric and eccentric exercises to receive muscular hypertrophy as well as neuromuscular function. 
• optimize neuromuscular coordination - proprioceptive re-education
• progress weight bearing - weight bearing and joint stress are necessary to enhance the functionality of the meniscal repair so should be progressed as indicated by the consultant. Excessive shear forces may be disruptive and should be avoided initially.
Physical exercise three times weekly during 4 months could lead to more than 35% improvement of knee function. Any rehabilitation program should be written on the patient’s body, every patient is different and will react differently to the rehabilitation.
The results are for a large part depended on the speed and exactness of how the diagnosis is confirmed.
Unresisted open chain exercises should be given to patients who underwent meniscal repair. Because the study of David L. et al. supports that it does not place undue stress on meniscal repairs. (LoE:4)
The findings of many studies support weight-bearing limitations during the initial 4 to 8 weeks after meniscal repair.In theory, weight bearing alone should not disrupt healing meniscal tissue, because the hoop stresses are primarily absorbed at the periphery of the meniscus. However, weight bearing in conjunction with tibiofemoral rotation during knee flexion, could produce shear forces capable of disrupting healing meniscal tissue.
Standard ‘cookbook’ protocols should be avoided and individualized programs - based on the type of surgical procedure, which meniscus was repaired, the presence of coexisting knee pathology (ligamentous laxity or OA), meniscal tear type, the patient’s age, preoperative kneestatus (including the time between injury and surgery), loss of ROM and strength, and the patient’s athletic expectations and motivations – should be encouraged.
Accelerated meniscal repair rehabilitation programs that permit full knee ROM and full weight bearing are becoming more common, with return to full activity as early as 10 weeks after surgery.
add links and reviews of high quality evidence here (case studies should be added on new pages using the case study template)
Arthroscopic meniscal repair from
the Bone and Joint Clinic of Houston
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