The Worker and Knee Arthroscopy: Options, Risks, and Benefits

Knee arthroscopy is a very common surgical procedure. It has essentially revolutionized the treatment of knee injuries. Many procedures that involved long incisions and months in a cast have now been converted to arthroscopic procedures with immediate rehab. Arthroscopy has many advantages. It tends to be less painful than open surgical procedures; the morbidity is less, particularly the risk of infection is much less; and the damage to any surrounding soft tissues is less if the knee joint is not opened itself. Also, it appears to decrease the recovery time, immediate range of motion and strengthening exercises may be instituted. However, arthroscopic surgery is not Band-Aid surgery, it is not laser surgery, and it is not the best option for some patients. In short, it is a major surgical procedure even though most patients have very good results.

The patient who injures his knee and who ends up needing arthroscopic surgery is usually a 35 to 60 year old male. Although females can be injured, there is a male preponderance. Frequently they have squatted and twisted in some way and felt a pop in the knee. As you get older, the trauma that is involved to create these injuries is less and less. Someone who is 60 may just squat and lift something and twist a little bit as he lifts, where as someone who is 30 is going to require more trauma to their knee in order to have a similar type of injury. The patient usually complains of popping, clicking, swelling, and locking in his knee. By locking, the knee actually catches and it won’t move. The physical therapist has to then kind of wiggle it around and move it, maybe even push on the knee in order to get it to start moving freely again. These are referred to as mechanical symptoms. Patients will have mechanical symptoms to varying degrees. Some will have all of these symptoms and some will have one or two of the symptoms. 

On physical examination, there is swelling noted in the knee joint, a knee effusion. There frequently is joint line tenderness directly over the medial meniscus or over the lateral meniscus, depending upon which one is involved. There are provocative findings which try to catch a torn meniscal fragment and cause it to click and pop. This is called a McMurray’s sign, which involves varus stress and range of motion, or an Appley’s sign, which involves compression of the joint with gentle internal and external rotation of the tibia.

Radiographs are absolutely vital in the work-up. They help to rule out any bony problems, but most importantly, they tend to assess the degree of pre-existing osteoarthritis. This is best determined on a single stance weight-bearing view. Radiographs will be your best clue to the patients who will be expected to have a great deal of chondromalacia or damage to the articular cartilage at the time of arthroscopic surgery. These patients will not have as good of a prognosis for recovery with surgical procedures.

Preoperative treatment
Preoperative treatment consists of light duty, avoiding lifting, bending, and squatting. We start patients on an immediate exercise program consisting of range-of-motion and strengthening exercises. The first week of a knee injury, 20% of the quadriceps muscle strength is lost. We want to overcome and prevent muscle weakness, and therefore start an immediate exercise program. Non-steroidal anti-inflammatory medications such as Motrin can be particularly helpful, especially if there is swelling noted within the joint itself. A knee sleeve is also quite helpful. 

Early orthopedic referral
Early orthopedic referral maximizes non-operative treatment. Up to 20% of meniscal tears are asymptomatic. Studies were done on asymptomatic people who had MRI scans and up to 20% of these were positive for meniscal tears, although the patient had no current symptoms whatsoever. Therefore, we feel that at least 20% of meniscal tears may calm down and not require any surgical treatment whatsoever. The other main reason for early orthopedic referral is to progress along the treatment modalities in a reasonable time frame. There are some people who are not going to improve, not operatively, whether they have one week or twenty weeks of physical therapy. There are other people who need to be given the chance to improve non-operatively. An orthopedic surgeon can best judge this time frame. 

Frequently we do receive what I would refer to as late orthopedic referrals. It is very difficult to treat a patient who, for example, has been in a knee immobilizer and off work for one month. When they come in, they then have a very weak and stiff knee, and they have been off work for one month trying to get the knee to improve. The problem is that rehabilitation is necessary first to regain range of motion and some of their strength before ever considering any surgical options. Therefore, it takes them twice as long to get ready to have the surgical procedure, and recovery time is longer as well.

Another significant problem is the patient who has been "overly treated" despite lack of improvement. This patient may have been in physical therapy and off work for a month with no improvement and has had a MRI scan. My biggest concern about this patient is that there has been a tremendous unnecessary expense with physical therapy for a month, being off work for a month, and his MRI scan. Very few of our patients actually receive MRI scans. 

So what is the appropriate time frame for operative treatment? It varies a great deal. If a patient has a locked knee, lacks full extension, has pain and swelling, and mechanical symptoms, he or she will require immediate surgical treatment. In this case there is a mechanical block to motion in the knee that will not improve without operative treatment. If a patient on the other hand has relatively few mechanical symptoms, very little clicking or popping, little to no effusion in his knee, he may be treated non-operatively for weeks or even months to try to get his knee to improve. If, however, there are many mechanical symptoms, this patient may end up having surgery sooner. 

Increasingly, we are faced with mandated time frames where insurance companies have said that you must treat patients non-operatively for six weeks before doing anything surgically. Most patients in our practice do receive this. With this time frame, some patients won’t improve during this period of time. Generally, if a patient shows no improvement in two weeks, four more weeks will not significantly improve the condition. Also, if there is a great deal of early mechanical symptoms, we will frequently shorten this period of non-operative treatment. Mandated lengths of non-operative treatment before considering surgical treatment is a serious concern simply because in many instances it is not appropriate. Secondly, the other mandated treatment that we are seeing is a preoperative MRI scan. I have several concerns about this also. First, MRI scans are expensive; they are anywhere from $500 to $1,000. The accuracy of the MRI scan is only 85%. Of those 85% of people, 20% of the population will have an asymptomatic meniscal tear, so at best your accuracy rate probably is around 65% to 70%. Second, MRI scans are extremely inaccurate for articular cartilage damage. So I tend to use MRI scans in two conditions: a confusing clinical picture that is difficult to separate out. and to justify non-operative treatment. Sometimes it is difficult for patients, possibly the work place, or insurance companies to accept the fact that nothing further can be done, and many times a normal MRI scan will help further support this clinical impression. They, however, can be misleading and should be used very judiciously.

Operative Treatment
We have moved through the non-operative treatment and discussed the role of radiographic imaging and MRI imaging, so let’s assume now that our patient has progressed to the point where he is going to require operative treatment. The necessary equipment is an arthroscope, a probe which is used to feel within the knee to look for meniscal tears, basket forceps to remove the torn tissue, and a motorized shaver that will help to smooth edges and remove any debris from the joint. 

The operative treatment is done as an outpatient. It is done through three small incisions. The knee is distended with saline-type fluid to allow for interior knee work. Afterward, the patient is on crutches about one to two days. If a meniscal tear has been repaired or if they have significant damage to the articular cartilage, they can be on crutches for anywhere from four to six weeks. The most important part of their rehab is to begin exercises immediately consisting of both range-of-motion and strengthening exercises. These exercises cannot be started too soon with the goal to avoid the atrophy and stiffness that tends to occur. 

Typically, during the arthroscopic surgery, we either do a partial meniscectomy or a partial removal of the torn piece of the meniscus or cartilage. At times, we can do a meniscal repair in which the torn piece is repairable. Only certain types of tears are repairable. Most of these are associated with ligamentus injuries. However, sometimes an isolated meniscus tear is repairable. If the meniscus repair is done, then patients are placed on crutches for approximately 4 weeks. Damage to the articular surface or chondromalacia is another common finding. This damage is usually treated with a chondroplasty to try to smooth some of the rough and irregular (or flap-like areas of the cartilage). Chondraldrilling is used to try to stimulate blood supply to grow back into these areas. 

As far as recovery, patients need to have full range of motion by four weeks. The strength should be regained by two to three months. Most patients can return to light duty work within two to three days, particularly if there is a sit down job available. If no light duty is available, and the job requires manual labor, returning to work can be two to three months. It can even possibly be longer, depending upon what is found inside the knee. Patients that have damage to the articular cartilage and have undergone a chondroplasty or a chondrodrillling will have prolonged recoveries. They can take even up to six months to improve as much as possible. The results from arthroscopic surgery are generally 85% to 90% good to excellent results. This depends a little bit upon the study that you read, and it also depends upon the findings at the time of surgery. As I mentioned previously, articular cartilage damage correlates with a worse result and a longer time frame of recovery. 

Potential Complications
Obviously with any operative treatment there are potential complications. Fortunately they happen infrequently in arthroscopic surgery. The most common complication is continued pain or decreased motion or function. This is most commonly related to damage to the articular cartilage within the knee. This is considered arthritis anytime the articular surface is damaged. This arthritis may be early or it can be late. By removing a portion of the meniscus, you are predisposing people to have arthritic changes in their knee later on. Patients may need further surgery; usually this is related to the arthritis in their knee. There is risk of infection, although arthroscopic surgery has a lower risk of infection than most open surgical procedures. The infection rate is less than 1%. There can be damage to nerves, tendons, and blood vessels. Anytime you have an anesthetic, there can be potential problems.However, statistically you are safer having an anesthetic than driving on city streets. Most medical problems consist of deep venous thrombosis. Obviously there is a concern of heart disease or lung trouble. However, arthroscopic surgery is relatively non-stressful on patients that have heart or lung type problems. Lastly, we can not predict all potential risks. 

Alternative Forms of Treatment
In considering alternative forms of treatment, certainly non-operative treatment is very appropriate, consisting of rest, exercises, non-steroidal anti-inflammatory medicines, activity modifications, and "living with it" or tolerating some discomfort in the knee. Frequently patients improve to the point where they do not require any surgical treatment. More sedentary people can often be treated in this manner. Other alternative methods include glucosamine, with or without the use of chondroitin sulfate. Glucosamine is marketed as a dietary supplement. It is not FDA approved. However, in good, well-controlled studies, it does appear to be as effective as anti-inflammatory medicines in the treatment of arthritic-type problems of the knee joint. It certainly can relieve some symptoms, however it does not promote cartilage growth; it does not promote cartilage healing; and does not repair cartilage damage in any way.

Hyalgan is a hyaluronic acid that has been obtained from the comb of a chicken and was felt to be helpful. This interestingly is FDA approved. However, in good, well-controlled studies, it has been shown not to be effective. More recently, we are working on cartilage transplants. A mosaicplasty is a procedure where a cartilage is taken from a different area of the knee, say around the kneecap, and transported to an area of the knee which is felt to be more important, and which has articular cartilage damage. There are several problems with this procedure, and this procedure probably ought to be considered at an experimental stage at this point. It can be effective in people that have isolated small traumatic defects where the articular cartilage is significantly damaged over a very small area. One exciting area is in the area of free cartilage transplant. One of the big concerns with this procedure, though, is how to anchor the cartilage cells once they have been grown. Current methods of anchoring them are not very effective and contribute to some deterioration of the cartilage at the sight of the anchoring. This, however, offers exciting future hopes for the ability to be able to better treat chondromalacia and to replace damaged cartilage. 

Cost
The operative treatment is certainly not inexpensive. The surgical fees depend upon what is found and what is done, and will roughly be $1,600. This certainly can be more depending how much work needs to be done inside the knee. The anesthesia bills are approximately $400 and the hospital bill is approximately $1,400. Physical therapy costs about $100 per visit, and as you know time off work is also expensive due to lost production to the company and lost wages to the worker.

One unresolved problems is an older worker who has no symptoms of arthritis in his knee, no problems with his knee, and then has an acute injury and complains bitterly of pain in his knee, and on x-rays has a significant amount of degenerative osteoarthritic changes within his knee. There obviously are two sides to this coin. On one side the insurance company and the work place may say he has had a lot of degenerative changes, and they are not responsible for those degenerative changes. Obviously, from the worker’s side, he feels as if he didn’t have any knee problems until his acute injury because he had no symptoms. I truly think that patients in this setting can have, if you will, the "straw that broke the camel’s back," that is the last little bit of articular cartilage is knocked off and then they begin having symptoms. We certainly see this happening in patients who are not part of the Workers Compensation system. This emphasizes the need for the single stance weight-bearing x-ray. This gives your best indication of the amount of osteoarthritic changes present preoperatively. It still is very difficult to assign apportionment to preoperative arthritic changes versus acute traumatic changes. However, this x-ray is probably the best tool to try to be able to do that. The treatment, particularly of older workers, who have acute injury to their knee, can certainly be complicated by these coexisting arthritic changes. 

Conclusion
The most important part is prevention. Anything you can do in the work place to avoid having workers bending, squatting, and twisting, is best. If injuries do occur, I would encourage you to please pursue early orthopedic referral. They need to have appropriate x-rays taken early to document the amount of pre-existing osteoarthritic changes within the knee. Hopefully, by early orthopedic referral, appropriate time frames for non-operative treatment can be followed. Careful selection of operative candidates will minimize costs and give the best results. There by allowing an early but safe return to work. This is particularly possible if light duty is available.