Tips to prevent injury and warning signs that something is wrong.

We use our knee joints for nearly every activity. As with any moving part, the knee joint is subject to overuse and abuse. Compound the normal use with a profession that requires bending, kneeling and squatting and knee pain is surely going to be on your list of ailments. Knowing how to prevent injuries and heeding warning signs when something is wrong will enable you to continue selling and servicing hvacr systems for years to come. 

Understanding the anatomy of the knee is crucial to preventing injury. The knee is basically a hinge joint. The upper leg bone (femur) articulates with the lower leg bone (tibia). There are two weightbearing surfaces of the knee, which are referred to as the medial (inside compartment) and the lateral (outside compartment) of the knee. In addition, there is a third compartment of the knee that consists of the knee cap (patella), which meshes with the femur and slides up or down as the knee straightens and bends respectively. 

The knee is cushioned between the femur and the tibia by cartilage. Cartilage (also known as meniscus) are spongy, C-shaped washer-type structures that are thicker around the periphery of the joint and thin as they come into the central portion of the weight bearing areas. The knee is moved by the muscles on the four sides of the joint. On the front side are the quadriceps, which help to straighten or extend the knee.

The knee joint also is supported by ligaments, which basically tie the bones together and provide stability to the knee. Joint movement is created through muscle contraction. The muscles are able to provide this movement through tendons — a structure that ties the muscle to the bone.

Employees who perform most of their work while standing can spontaneously begin to have pain related to the progression of osteoarthritis in the knee where the cartilage begins to deteriorate. As we get older our knee-supporting structures can become more brittle. 

It is also important to realize that all knee pain may not be emanating from the knee joint itself. For instance, if someone has a hip ailment, it is quite possible that instead of having the classic groin pain, someone may have knee pain. 

In addition, lowerback issues, especially a herniated disc causing a pinched nerve, also can result in more leg pain or even knee pain than back pain itself.Common Ailments Chondromalacia patella — The under surface of the knee cap (the cartilage layer) develops deterioration. Oftentimes this deterioration is caused by an abnormal alignment of the femur to the tibia or the ankle to the knee. However, it also can be caused by people who are kneeling or squatting excessively or performing climbing functions. 

Symptoms progress gradually and are generally made worse with kneeling, squatting, climbing stairs or even just sitting with the knee in a bent or flexed position over a long period of time. Other symptoms may include swelling and clicking or popping, especially noticeable up and down stairs. 

If this diagnosis is presumed, treatment includes anti-inflammatory medications, icing and attempts to avoid the exacerbating positions. Also, strengthening exercises for the quadriceps would be prescribed. The strengthening should be from a fully straight knee to just about a 30-degree bend and then retightening the quads all in an attempt to try to improve the tracking or the alignment of the knee cap.

Torn cartilage (meniscus) —Torn cartilage is equally common in the young athletic population from acute traumatic events as it is from chronic repetitive overuse in the middle age to older population — especially those who work in a squatting position with rotation of the knee over a long period of time. 

Symptoms can come on gradually or may be caused by an acute traumatic event such as pivoting. Once the cartilage is torn, symptoms may be exacerbated by weight-bearing activities (especially squatting or pivoting), and running or climbing.

 Swelling may be associated as well as locking or catching, which is essentially having the knee get stuck in a bent position. The patient may also complain that the knee “gives way.” However, it would be more related to pain or anticipated pain as opposed to true instability. If a variety of these symptoms are present and conservative management consisting of anti-inflammatory medications, rest and avoidance of exacerbating activities are not successful, a visit to your physician for X rays and possibly an MRI is warranted. The orthopedic surgeon may recommend arthroscopic surgery to resolve the problem.

Ligament injuries — These are usually caused by acute traumatic events. A fall from a height or a force striking the knee from one of many different angles can cause ligaments to tear. Generally speaking, when a significant amount of energy is applied to the knee and a tear is sustained, a “pop” or “snap” or actually feeling a tear would be noted. If this occurs, a visit to your doctor is required. 

Torn collateral (medial and lateral) ligaments can generally be managed with bracing and physical therapy. A tear to the anterior cruciate ligament (ACL) in a patient with a demanding profession may require surgery. A posterior cruciate ligament (PCL) can generally be managed with physical therapy and bracing.

Dislocation of the knee cap — This can occur with a blunt trauma or during a bent-knee pivoting maneuver. One can generally tell when the knee cap has slid off to the outside or lateral part of the knee. Oftentimes this injury needs to be set in an emergency room.

Overuse — Overuse injuries are the most common knee ailments related to work. The knee is particularly vulnerable for hvacr workers because the profession requires workers to climb ladders and stairs and work in tight quarters with the knee in the flexed position.

Patellar tendonitis — This can begin in the area just below the tip of the knee cap extending all the way to the small bump on the shin bone about three inches away from the tip of the knee. Pain is gradual and is almost always associated with some weakness due to a significant amount of squatting and rising. Tenderness is located along the course of the patellar tendon. 

Treatment is rest and avoidance of all exacerbated activities, ice and gentle stretching. If that doesn’t resolve the pain, a visit to the physician’s office and utilization of a knee immobilizer is required. The scenario is much the same for quadriceps tendonitis except for the location of the pain is above the knee cap as opposed to below.

Osteoarthritis — A gradual onset of pain and knee stiffness in the morning are warning signs of osteoarthritis. The patient also may experience the knee locking or catching and sometimes even the feeling of “giving way.” The patient also may realize a changing of alignment in the knee either from front to back or side to side, which is due to loss of cartilage space that can cause an increased misalignment and symptoms. 

The patient also may complain of swelling or warmth above the knee and have difficulties with activities. Tenderness can be localized to the joint line and there can be a variable amount of loss of range of motion, strength and alignment. Following evaluation, if the diagnosis of osteoarthritis is made it is very important to begin a protocol of strengthening rangeof- motion exercises, endurance exercises, and flexibility exercises. 

Increase cardiovascular fitness with low-impact exercises like bicycling or swimming. One should try to obtain as close to ideal body weight as possible. Oftentimes it is best to work with first a physical therapist then a personal trainer only allowing progression of endurance or resistance of the exercises as one improves.

Medication—Medications can vary from over-the-counter nutritional supplements like glucosamine and chondroitin to Advil or Aleve and non-steroidal medications that also can be over the counter. Tylenol and acetaminophen can be administered to relieve pain, but do not reduce inflammation. As with all medication, read the bottle for appropriate doses.

Doctor-prescribed therapies include SYNVISC injections or HYALGAN injections, which are placed directly into the knee and help coat the joints surfaces. This therapy is ideal for mild to moderate arthritic patients. Oftentimes physicians will administer steroids into the joint to help alleviate inflammation.The newest evolution of anti-inflammatory medications are Cox-2 inhibitors. 

The only one still on the market is Celebrex. These inhibitors have been somewhat controversial with regard to cardiac patients and those with certain allergies. If conservative treatment doesn’t work, surgery may be required. In addition, surgery may be necessary for broken bones or ruptured tendons depending on their location and alignment. It is also very common to administer arthroscopic surgery for torn cartilage or ligaments in the knee.An ounce of prevention regarding knee ailments is essential in the workplace. 

Pay special attention to knee alignment, job mechanics and ergonomics and condition properly for the job at hand. Having significant muscular strength, flexibility and endurance to meet the job requirements is essential. Workers should not stay in a kneeling position for long periods of time and should always wear appropriate levels of knee pads. Additionally, sufficient quadriceps strength will enable you to meet the demands of getting up and down from a squatting position multiple times a day. 

Alan is an orthopedic surgeon and sports medicine physician affiliated with The Cleveland Clinic Foundation. He is a member of the National Board of Medical Examiners, American Academy of Orthopaedic Surgeons, and the American Orthopaedic Foot and Ankle Society. 
Pamela is a practicing dermatologist at MetroHealth Medical Center in Cleveland, Ohio, and is an assistant professor at Case Western Reserve University. She is a member of the American Board of Internal Medicine as well as the American Board of Dermatology and is a member of the American College of Sports Medicine.