Reconstructed anterior cruciate ligament

Anterior Cruciate ligament is torn while its ability to withstand the load is overcome by the force of injury. ACL is commonly injured with

• Twisting injury to the knee
• Hyperextension injury
• Abnormal sideway opening of the joint ( varus or valgus)

Depending on the amount of force, other structures are injured along with ACL. These include Meniscus, PCL and collateral ligaments. ACL injury is actually a spectrum of injury ranging from an isolated ACL injury (e.g., sports, low velocity injury) on one end to debilitating multi-ligament injuries (Road accidents etc.) on the other.

Like many other joint structures, ACL also has very poor blood supply and hence it has very poor healing potential. The healing potential is further compromised by the presence of joint fluid, which inhibits clot formation and healing response. Most of the time ACL is torn completely. Partial tears are rare and may progress to complete tears.

Clinical Features

When an ACL is torn the patient may feel a "pop" like sensation in the knee and may have difficulty in standing immediately after surgery. In most of the cases, a knee swelling (hemarthrosis) develops within few minutes due to the bleeding from the torn ligament. However, ACL can be torn without a knee swelling also. The subsequent disability of the patient depends on ACL deficiency as well as the amount of injury to the associated structures of knee. If only the ACL is torn, the patient will be able to walk, but the knee will buckle (give away) when he changes the direction while walking (pivoting and cutting). Additional injuries to meniscus and cartilage will result in episodes of locking, pain and joint swellings.

Diagnosis

Most of the ACL injuries can be diagnosed by clinical examination. Clinical diagnosis may be difficult if the patient is having a lot of pain and spasm. In this situation, an examination is performed at a later stage. MRI is valuable in diagnosing ACL as well as other injuries and is useful in some patients.

Treatment

Because of the poor blood supply, repair (bringing together the torn ends by suturing) will fail invariably and is no longer practised. Reconstruction of the ACL is the ideal treatment. In this method a band of tissue (Graft) is harvested from around the knee and is placed in the original position of the ligament. Two common grafts are practised in Ortho One.

• The Bone Patellar Tendon Bone Graft (BPTB) graft consists of the middle third of the patella tendon, a small piece of bone from the knee cap and from the tibia
• Another graft source is the tendons of Hamstring muscles, semitendinosus alone or with gracilis. Allografts are tissues taken from dead donors. Though available abroad, we do not use them here currently.

For fixing the grafts, passages (tunnels) are made in the tibia and femur, and the grafts are passed and fixed using implants. A variety of fixation techniques and implants are available.

Reconstruction of the ACL is one of the commonest surgeries to be performed with predictable results. More than 3,500 reconstructions have already been performed at Ortho One. The surgery is done arthroscopically, but to harvest the graft, we make a 3 to 4 cm skin incision below the knee.

MENISCUS - Torn & Locked

The Meniscus is the shock absorber of the knee. Blood supply can be found only in the outer margins of the meniscus and most of the inner regions lack any blood supply. Because of this, only tears occurring in outer margins have the potential to heal.

The Meniscus usually tears in various patterns. It can produce symptoms like pain, repeated joint swellings (effusions), locking and catching. Diagnosis of meniscus tears is by clinical examination and in doubtful cases, MRI.

Meniscus tear is usually treated according to the blood supply in the region. Tears occurring in the regions with blood supply are treated with Meniscus repair, while those occurring in an area without blood supply are trimmed to leave behind a smooth rim of meniscus. (Partial Meniscectomy).

Early presentation for surgery is crucial for meniscus preservation. With late presentation, the chances of success following a repair come down because of poor tissue quality. Considering the vital role of the meniscus in knee function, every attempt is made to preserve the meniscus.

Badly damaged cartilage in chronic ACL deficiency

Cartilage is responsible for the smooth gliding movements of the joint. Cartilage injuries can occur along with ACL ruptures at the time of injury or because of the repeated instability associated with ACL deficient knee. Only a localized part of the cartilage is injured and hence they are called focal cartilage injury. Cartilage injuries are difficult to diagnose clinically and in MRI. Arthroscopy is the only modality, which can clearly visualize the injury and treat it.

The cartilage injury is graded according to depth and extent. Superficial lesions are debrided and smoothened. For full thickness lesions either Microfracture Chondroplasty or autologous osteochondral transfer (mosaic plasty ) is carried out.

Compared to ACL injuries, PCL injuries are rare and mostly missed. They occur in road traffic accidents and falls. PCL injuries cause the tibia to move backward abnormally. The degree of PCL injury is graded according to the severity.

• Grade I and II are treated non-operatively
• Grade III and IV injuries are treated by arthroscopic PCL reconstruction. For PCL reconstruction, the quadriceps tendon with patella bone as graft is used

Knee dislocations are rare but can be devastating. They are associated with multi-ligament injuries. After reduction and a period of rehabilitation, singe stage multi-ligament reconstruction is carried out to stabilize the knee.

Injury of the Medial Collateral ligament (MCL) which supports the inner aspect of the knee is quite common. MCL injuries are graded according to the severity.

• Grade I is contusion
• Grade II is partial tear
• Grade III is complete rupture

MCL has a good healing potential and surgery is not required. MCL injuries are treated initially by rest, ice compresses and anti-inflammatory medications. Once the pain comes down, the patient is ambulated with non-weight bearing and knee ROM.

The treatment of Lateral Collateral Ligament (LCL) injuries is much more complicated. Usually the LCL is injured along with the neighbouring structures called Posterolateral Complex (PCL). Most often these groups of structures are injured along with ACL or PCL. As this complex is necessary for day to day function of the knee, any laxity in these structures is unacceptable. Repair of the structures gives good results (within 3 - 4 weeks) and delayed cases need reconstruction of these structures. Good PLC function is important for the success of ACL or PCL reconstruction. Any PLC laxity found during ACL or PCL reconstruction is treated by reconstruction. PLC reconstruction has to be done by open surgery only.

The patella (knee cap) is also the source of many problems. The knee cap moves in a groove of the femur during knee flexion and extension. In some patients the knee cap slips out of the groove and comes to lie on the outer aspect of the knee. Many factors like, muscle imbalance, altered anatomical development and ligament laxity play a role in the causation of this problem. It requires surgical intervention if it occurs more than once. The surgical treatment includes strengthening the torn / loose ligaments and releasing the tight structures. In a select few, bony procedures to correct development of bony problems may be necessary. The relevant procedures will be decided for each patient after thorough clinical and radiological evaluation.

Knee pain is very common in young as well as old people. Not every knee pain is associated with structural damage. However, the cause of the knee pain has to be assessed clinically. If necessary, investigations like MRI are done. In the absence of structural damage to the knee, a rehabilitation program is started with individualized physiotherapy to correct muscle imbalance and tightness.

Synovium is the lining membrane of the joint which secretes the joint fluid. The synovium can be affected in many diseases, leading to swelling of the membrane, fluid collection etc.

The basic disease producing the inflammation should be identified and treated. Rarely, the synovium proliferates and produces cartilaginous nodules (Synovial Osteochondromatosis). The nodules get detached from the synovium and become loose bodies in the joint. Arthroscopy is very useful in removing the loose bodies and the diseased synovium. Pigmented villonodular synovitis is another rare disease of the knee producing painless swelling of knee and later joint erosions.

Arthroscopy has a significant advantage in removing the synovium, when compared to open procedures, as the front, back and sides of the joints can be approached by few 10 mm skin incisions.