Meniscal Tear And ACL Tear In Sports Medicine

Farid A. Hakim, M.D., Jacksonville, FL

Among the diverse injuries to the knee, we will explore two pathologies commonly seen in sports activity, the meniscus tear and the anterior cruciate ligament (ACL) tear.

The Meniscal Tear

Introduction

The meniscal tear represents approximately 50% of knee injuries that require surgery. The medial meniscus is torn approximately three more times than the lateral meniscus. In some literature, this ratio is even higher. Two types of meniscal tears exist, the traumatic and the degenerative. The traumatic tears occur in younger patients with sports related injuries. They may be more peripherally located (and therefore may be repaired.) They may also be associated with ACL injuries. Degenerative tears usually occur in older patients, they are most insidious in onset and are more commonly complex with many different patterns, these tears are usually not repairable.

History and Physical

History often reveals a twisting injury with moderate swelling, loss of motion and late mechanical symptoms. Many times, the causing injury is not recalled. Careful palpation of the joint line may identify tenderness, localized swelling, or a meniscal cyst, all suggestive of meniscal tears. The squat test and the McMurray test, when present help in the diagnosis.

Classification

The meniscal tears can be classified on the basis of location or the orientation and appearance.

 

The classification by location is based on the blood supply to the meniscus. Most meniscal tears located in the peripheral third of the meniscus (figure 1) are within the vascular zone and have a high chance of healing if a repair is done. The meniscal tears located in the central third of the meniscus are in the a vascular zone and have no chance for healing. The meniscal tears located in the middle third have intermediate chances of healing potential. Tears, on the other hand, can be classified as longitudinal, radial or oblique based on their orientation. Several terms have been used to describe the appearance of certain meniscal tears such as bucket handle tear, parrot beak tear, and flap tear (Figure 2).

Figure 1

Figure 2

Treatment

The goal in the treatment of meniscal tears is the preservation of the meniscus when possible. It has been proven that any deficiency in the meniscal substance leads to a potential risk of arthritis in the future. The option to repair the meniscus should always be considered. In the young age group it should be the rule rather than the exception. Bone scan studies on knees after partial meniscectomy or total meniscectomy have shown several degrees of increased uptake on both sides of the joint which is a prelude for osteoarthritis. The treatment of meniscal tear is through an arthroscopic procedure.

Partial Meniscectomy

Various types of surgical equipment and techniques are available for arthroscopic meniscectomy. Probing the meniscus is important to assess the damage and to be able to locate the tear which is an important factor in deciding for a meniscectomy or for repair. Central types of tears, as well as radial types of tears are usually treated with partial meniscectomy as they are in an avascular zone of the meniscus. Degenerative tears of the meniscus are also treated with partial meniscectomy. The partial meniscectomy is done using different types of tools varying from small knives or sharp instruments that cut the meniscus by taking small bites or using laser or radio frequency techniques. These instruments are used at the discretion of the orthopedic surgeon's preference.

Meniscus Repair

Meniscal repair has only been recently adopted into a routine practice. The meniscal repair should be considered in all tears located in the middle third, peripheral third and longitudinal tears including bucket handle tears of the meniscus. Four techniques for meniscal repair are used: Open meniscal repair, arthroscopic inside-out repair, arthroscopic outside-in repair, and arthroscopic all-inside repair. Again, the application is a matter of the surgeon's preference and experience. For each of those described techniques, many tools are available on the market including stitching or using anchors or sliding knots.

Meniscus Transplantation

In the event of total meniscectomy for extensive non repairable tears, meniscal transplantation with allograft is a treatment option. Indication includes mainly symptomatic knees in relatively young patients. Following this procedure, return to high demand sports activities is not recommended. The results, for this relatively new technique, are encouraging, and the procedure should be widely available in the next few years.

Postoperatively

Following partial meniscectomy weight bearing is started immediately as tolerated, with physical therapy starting within a few days following the procedure. Return to sport may start as soon as the patient has recovered full range of motion and adequate strength of the musculature around the knee. Following meniscal repair, we recommend starting physical therapy within a few days of the procedure but the patient should remain non weight bearing following meniscal repair for a period of four to six weeks according to the size of the tear and the quality of the repair. Gradual weight bearing follows, and the return to sport may start at three months from the date of repair. Following meniscal transplant, gradual weight bearing is only started at two months.

The Anterior Cruciate Ligament Tear

Introduction

Although injury and treatment of ACL tears have become a major focus in orthopedics, considerable controversy still surrounds the natural history of this injury. Indications for repair still vary among orthopedic surgeons for different reasons including level of activities of the patient, age of the patient as well as the surgeon persona experience and training. Treatment decisions must be individualized and most orthopedic surgeons now recommend ACL reconstruction in relatively young and active patients who are involved in sports activities, to prevent recurrent injuries particularly the meniscal tear.

History and Physical Examination

Most of ACL injuries are a result of low velocity, deceleration, rotational injuries and frequently are non contact injuries. The patient relates a pop at the time of injury and most of them are not able to return to sport immediately after the injury and this creates an acute onset of swelling. Associated injuries are common including meniscal tears and about 50-75% of these will bear ACL injuries, and combined ligamentous injury including medial collateral ligament, lateral collateral ligament or posterior cruciate ligament. Clinically, the presence of a positive Lachman test, anterior drawer's sign, or a pivot shift, is indicative of a torn ACL. MRI is the best non invasive tool for diagnosis.

Treatment

1. Conservative treatment with anti-inflammatory medication, icing, rest and physical therapy in very stiff knees is indicated as initial therapy for all ACL tears. Supplementation with a brace helps decrease the anterior translation of the tibia.
2. Surgical treatment should be tailored to each patient for the indication and the type of reconstruction. Many surgical treatment options exist. Primary repair is no longer a viable option. Extra-articular reconstructions are no longer in use except for very limited cases including open growth plates in very young patients.

Intra-articular reconstruction has become the gold standard for active patients with ACL injuries.

(1) Graft selection: Two general categories of graft are available for ACL reconstruction, autografts and allografts. The most commonly used autografts includes the bone/patellar tendon/bone (BPTB) which is the middle third of the patellar tendon with two bone plugs at each end, one from the patella and one from the tibia, and the hamstrings that are the gracilis tendon and the semitendinosis. Allografts can be selected among different donor sites including BPTB, Achilles tendon, quadriceps tendon with patellar bone plug or the tibialis posterior tendon. Completely or partially synthetic grafts are rarely used. The bone/tendon/bone autograft is the most popular graft and has been shown to be an excellent choice. Nevertheless, some morbidity, such as patellar fracture and the development of late patellofemoral pain may result from its use. For this reason, the hamstring graft has become popular in some centers and is gaining ground on the BPTB autograft. Although the hamstring graft is not as mechanically strong as BPTB graft, some surgeons advocate double, triple or quadruple thickness graft which may exceed the mechanical strength of BPTB grafts. One potential draw back to the use of hamstring graft is that fixation must be performed with soft tissue techniques or with sutures tied over a post. Both of these methods have been shown to be mechanically inferior to bone fixation with interference screws as with the BPTB grafts. The reports comparing hamstring and BPTB autograft demonstrated a greater laxity in the hamstring group. Most recent reports are encouraging mainly with techniques that use quadruple thickness graft and the newer soft tissue fixation devices. All grafts have the advantage of no donor site morbidity and procedures can be carried out through smaller incisions. Potential risks include transmission of infection including HIV and Hepatitis. Those risks are low and range from 1 per 50,000 to 1 per 1,000,000. Additionally, the grafts that are irradiated with more than 2.5 millirad or centigray lose mechanical strength. Some reports describe widening of the osseous tunnel with allografts. Some explain it as a possible immune reaction to the allograft tissue. Allografts have also been known to have a delayed graft incorporation time in studies when compared with autografts.

(2) Surgical principles: Most of the new techniques for ACL reconstruction involve mini-incisions just medial to the tibial tuberosity. The procedure is arthroscopically assisted with regular arthroscopy portal. When BPTB autograft is used a larger incision is used anteriorly in the midline extending from the distal point of the patella to the tibial tuberosity. During the procedure, tunnels are made through the tibia and femur with the goal of recreating a normal path of the ACL. Interference screws are used for the bone plugs. Some techniques use anchors attached to the end of the bone and the soft tissue is fixed with either, interference screws specially designed for soft tissues or stitches attached to a post.

Postoperatively, the patient is allowed weight bearing as tolerated with crutches for the first week. ACL brace is applied and physical therapy with active and passive range of motion and strengthening is started within days of the surgery. Weight bearing is not allowed if a meniscal repair is done at the same time. Rehabilitation time range from as little as six weeks up to six months. The patient is instructed to avoid any body contact type of sports activities, heavy physical work or any physical activity involving twisting of the knee, including racquet sports, for nine months from the date of surgery. Wearing ACL brace is recommended with activities.

Complications

Complications in ACL surgery are often a result of technique. These include patellar fracture, aberrant tunnel placement, graft failures from impingement, failure of fixation and other problems including infection. One of the major problems following ACL surgery is loss of motion. Some sources relate the stiffness after ACL reconstruction to surgery in the acute setting and recommend three to four weeks after injury before surgery. Immediate postoperative motion is also important in avoiding these complications. Stiffness was more common in the past when immobilization after ACL surgery was common treatment.

Overall results with ACL reconstruction are excellent and give the patient a lot of satisfaction and ability to return to sports activities.

Jacksonville Medicine / August/September, 2001

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