By Rodney Herrin, M.D.
Board Certified Orthopedic Surgeon
Orthopedic Center of Illinois
Anterior Cruciate Ligament Injuries
There have been significant advances in the management of sports knee injuries, with the primary focus on attempting to restore the normal anatomy. The anterior cruciate ligament is an important stabilizer of the knee. (See Figure A) Once the ligament is injured, the knee may “give way “. When this occurs, additional injury may occur to the knee including injury to the meniscus or the articular cartilage of the knee. Therefore, often times when the anterior cruciate ligament is injured, surgical intervention is recommended. Anterior cruciate ligament reconstruction has evolved toward reconstruction of the ligament on an anatomic basis. A better understanding of the anatomy has helped with our reconstructive techniques and improvement in our surgical technology. By paying more attention to the anatomy we are able to improve the results for our patients.
When an anterior cruciate ligament reconstruction is being performed in the setting of a relatively acute injury, typically the attachment sites of the anterior cruciate ligament on the femoral and tibial sides are present. These attachment sites can be used as references for reconstructing the anterior cruciate ligament. In this setting, the center of the attachment sites of the anterior cruciate ligament can be marked with electrocautery. The goal is then to try to place the tunnels for the reconstruction in those locations. The anterior cruciate ligament typically cannot be repaired and therefore must be reconstructed. This may be done using either the patient’s own tissue (autogenous tissue) or using a donor tissue (allograft tissue). The autogenous graft options include the use of a bone patellar tendon bone graft, hamstring graft, or a quadriceps tendon graft. The allograft options include bone patellar tendon bone, tibialis anterior, as well as Achilles tendon just to name a few. Generally autogenous tissue is used in the younger athletes, which may help decrease the risk of re-injury. As the patient matures, both autogenous or allograft tissue are reasonable options. Figure B demonstrates an anterior cruciate ligament reconstruction. The procedure is typically done arthroscopically. There are a multitude of options for fixation of the grafts, the type of fixation used is partly dependent on the graft choice. For example, a graft that has a bone plug attached to it, such as a bone patellar tendon bone graft, will typically use interference screws. However, there are many acceptable options.
A current trend after anterior cruciate ligament reconstruction, is to proceed somewhat slowly when it comes to rehabilitation and returning to sports. It is felt that trying to return the athlete to their sport too rapidly may increase the risk of reinjury to the knee.
The meniscus is a fibrocartilaginous structure that helps protect the joint surfaces of the knee, and is commonly injured. We have learned that the more it can be preserved the better. Most commonly a torn meniscus is treated with a partial meniscectomy, preserving as much of the meniscus as possible. In some instances the meniscus is torn in such a way that the meniscus can be repaired. There many techniques that are available to help us with that task. The meniscus may be repaired with sutures that are placed from inside the knee to the outside of the knee. This technique is still considered the gold standard, however there are many evolving techniques that are very helpful for meniscal repair. These include techniques that are considered “all inside”, which has the advantage of being somewhat less invasive. Figure C is an example of an “all inside” meniscal repair technique.
Meniscal Root Repair
Occasionally the meniscus is torn at its posterior root attachment. Once that occurs, the meniscus is essentially rendered nonfunctional and no longer protects the knee as it is designed to do. Repairing the meniscal root tear can be quite beneficial to the patient and the techniques to do so have significantly improved with the improvement of technology. Essentially sutures are placed at the root of the meniscus and then a drill hole is placed in the area of the meniscal root attachment. Once that has been done, the sutures are pulled through the drill hole that has been made and the sutures are tied over a button. (See figure D) This pulls the meniscus back to its anatomic attachment and restores the hoop stresses in the meniscus that protects the knee.
In certain circumstances, the meniscus cannot be preserved. If a significant portion of the meniscus has been removed and the patient becomes symptomatic related to the absence of the meniscus, the patient may be a candidate for a meniscal allograft transplant. (See figure E) To be a candidate, however, the patient needs to have relatively normal articular cartilage and have satisfactory alignment of the lower extremity. The procedure involves transplanting an appropriately sized donor meniscus into the knee of the patient. The procedure is primarily done for improved symptoms and paint relief, but, is not typically performed with the goal of returning the patient to significant sporting type activities. It has not been proven that the meniscus transplant protects the knee from developing degenerative changes in the future. The procedure can be technically demanding and does require obtaining the appropriately sized meniscal transplant. In the appropriate patient however, it can be a reasonable option to consider.
Articular Cartilage Problems
The articular cartilage in the human knee has a limited blood supply and therefore, once injured, it cannot heal itself. There are numerous ways to try to manage articular cartilage injuries and a great deal of research that is being done regarding treatment of these injuries. The treatments can range from a technique known as microfracture to techniques such as autogenous chondrocyte implantation (ACI). The technique of microfracture (See figure F) has been around for decades, but it is currently being modified to potentially help it be more successful. The technique of microfracture involves a process where the body fills the defect in the articular cartilage with fibrocartilage. Although this is helpful to patients, the fibrocartilage is typically not as long lasting as normal hyaline articular cartilage. Currently, the goal in management of articular cartilages problems is to develop cartilages more similar to hyaline articular cartilage, which is normally present in our knees. Hopefully, this cartilage will be more durable and have longer benefit for the patient. Methods that attempt to regenerate closer to normal articular cartilage include techniques such as Autogenous Chondrocyte Implanation (ACI). This is a technique where the patient’s own articular cartilage cells are harvested and cultured and then re-implanted. (See figure G) Additionally, research into techniques that involve the use of stem cells, for example, may prove beneficial in the future.
Problems from the patellofemoral joint can come in several varieties and may be related to patellar pain, patellar instability, or arthritis of the patella femoral joint. Typically, patellofemoral pain in a patient with a normally aligned patellofemoral joint is managed nonoperatively. Proper rehabilitation techniques, including strengthening of the core and pelvic musculature, as well as the quadriceps and hamstring musculature, can be helpful.
The problem of lateral patellar instability can be extremely disabling. Techniques continue to evolve toward restoration of normal anatomy and can be quite helpful to this group of patients. When a patella dislocates, often times the medial restraining structures become injured and may result in the patella becoming chronically unstable. These injured structures can be addressed in the form of a medial patellofemoral ligament reconstruction. (See figure H) Essentially, this technique uses tissues to reconstruct the medial patellofemoral ligament, which acts as a restraint from having the patella dislocate laterally. Additionally, care must be taken to make certain that the distal portion or “pull” on the patella is aligned properly as well. If alignment is found to be problematic, then realignment of the distal portion of the patella with a tibial tubercle osteotomy may be indicated as well to allow for proper “pull” on the patella. If there are problems with alignment of the patellofemoral joint, then all contributing factors should be addressed. By stabilizing the patellofemoral joint, the patient then can often times be much more active and have a knee that feels more reliable.
The alignment of the knee is very important for proper function of the knee and that principle applies should any sort of reconstructive procedure be needed, as well. Typically the weight bearing axis of the knee passes from the center of the hip, to the center of the knee, and down to the center of the ankle. If the knee is malaligned, there will be increased force and potentially increased wear through the compartment where the alignment is passing through. A malaligned knee would be a contraindication to the procedure such as an articular cartilage restoration procedure or a potential meniscal allograft. Fortunately, there are techniques that have assisted in making the osteotomy more reproducible and also decreasing the morbidity of the procedure. These procedures can be done by either a closing wedge technique or an opening wedge technique, but the tendency appears to be more for the opening wedge technique. (See figure I) Additionally, the procedure can be done in the young active patient to try to help preserve the knee rather than perform an arthroplasty (replacement) of the knee. For example, if the patient has significant wear and symptoms coming from the medial compartment of the knee, an osteotomy can be performed that allows for the alignment to be transferred to the more normal lateral compartment of the knee. This can allow the patient to remain active in activities without concerns over the arthroplasty loosening or wearing out. It is another technique in the armamentarium of orthopedic surgeons practicing the technique of joint preservation surgery. As our technology for fixation and alignment has improved it has helped with our patients outcomes and potentially has decreased the risk of complications.
When performing a surgery the surgical technique is extremely important, however just as important, is the proper postoperative rehabilitation. Advancement is occurring in and a great deal of research is going on in the area of orthopedic rehabilitation. For example, we have learned that in patients with patellofemoral joint problems, strengthening the muscles of the core and pelvis is just as important ,if not more so, than strengthening the muscles about the knee. Additionally, we have learned that going a little slower with rehabilitation after an anterior cruciate ligament reconstruction may decrease the risk of reinjure.
In summary, the techniques to manage sports knee injuries continues to evolve and improve. It is an exciting area of orthopedics. At the orthopedic Center of Illinois, our board certified physicians are dedicated to keeping up with the latest techniques to allow us to provide our patients with the best current orthopedic and sports medicine care.
This article was published in the July-September 2015 edition of ”FYI from OCI”, a quarterly publication created by the Orthopedic Center of Illinois. To see the full publication, click HERE.