Case Study

Don is a 63-year-old male with a left total knee arthroplasty on 2/17 due to osteoarthritis. Osteoarthritis is a joint condition in which the cartilage on the end of bones is broken down over time due to repeated mechanical stresses. It is most common in weight bearing areas such as the knees and spine but can occur anywhere in the body. In severe cases, a joint replacement is recommended, in which the articulating joint surfaces are reconstructed with metal. Between 20-27 million people in the U.S. have osteoarthritis with the majority being older patients. Risk factors include obesity, weakness of the quadriceps muscle, and occupational activities that require a lot of squatting and bending.

In Don's case, he has worked at a farm machinery retail store for about 20 years and states that his job requires a lot of squatting and lifting heavy machinery parts. This, combined with his age and improper body mechanics, led to the onset of his arthritis, leading to his need for a joint replacement. After an overnight stay in the hospital, he was discharged and referred to physical therapy two days later.

During his initial evaluation, Don stated that his knee was stiff in the mornings and he slept in the recliner since his bed was uncomfortable. His home was a single floor home with a basement, but he only used the main floor and only needed to climb a few stairs to get into his house. He had been icing his knee for the first few days as told by the surgeon. In addition, he had been prescribed anticoagulants and compression socks to reduce the risk of developing a DVT.

Upon initial observation, Don was using a walker and ambulated with a limp. It was noted that he had visible swelling in the left lower extremity. Manual muscle testing revealed significant muscle weakness in his left quadriceps, with a grade of 2/5 for hip flexion and 2+ knee extension, and 3 for knee flexion. Comparatively, right lower extremity strength was 5/5, with the exception of 4/5 for hip flexion. For range of motion, he had pain with 78 degrees of knee flexion and 7 degrees of an extensor lag. The surgeon set a goal of 115 degrees of knee flexion.

Treatment mostly focused on improving his functional mobility and strength so he could get back to work as soon as possible. The plan of care included neuromuscular re-education, manual therapy, gait training, and therapeutic exercise as appropriate. In the beginning, increasing range of motion and ambulation were the most important goals. For people with total knee replacements, it is critical that they start ambulation and range of motion right away, as the tissues heal relatively quickly and can limit gains in these areas. In addition, Don received neuromuscular electrical stimulation and light strengthening for quadriceps control and improved gait. The quadriceps has an important role, especially during single leg support and just before swing phase initiation (Giles, 33). Establishing muscle control is foundational for strength. Other goals included decreased pain, improved single leg stance, ambulation on smooth and uneven terrain, reciprocal stair climbing up 4 steps, and improved bed mobility and transfers.

For the first 3 weeks or so, coming in at 2 days a week, we worked on hip and knee muscle setting, active range of motion, and gait training to keep his leg moving and reduce swelling. In the beginning of each session, we started Don on a NuStep machine for a few minutes, which simulates the motions of walking and targets the same muscle groups. For exercises, we worked on supine heel slides, quad sets, and glute sets, and standing heel raises and hamstring curls, which was his initial home exercise program. Other interventions included NMES on his quadriceps to establish muscle control. We started with short arc quads on a bolster, progressing to long arc quads once these were too easy. By the third week, he was walking with a significantly lesser limp and demonstrated greater quad control with the exercises, so we discontinued NMES. To replace it, we tried active assisted straight leg raises. We added more standing exercises to his HEP to improve strength and balance, such as sit to stands. He started by standing from sitting on a pillow, progressing to the chair seat as his quadriceps got stronger. As his knee was feeling better, we told him to limit ice usage to decrease scar tissue formation. Gradually, we began to wean him off the walker to a cane, telling him that he could use the cane around the house but to continue using the walker in public places.

Once Don had minimal swelling and pain, we focused more on strength and endurance while continuing to use and improve knee range of motion. At this point, his original limp significantly improved, so we told him he could use his cane in public, but if he was going to anywhere crowded to use his walker. To build up his endurance, he went to the gym, used the NuStep and was able to walk at least 5-6 laps with almost no pain. There were times he came into the clinic with pain, so we had to remind him not to overdo activities, as tissues are still healing even if they aren't hurting at this stage. This did not set him back but just needed to be addressed early on to prevent future problems.

To progress strengthening, we worked on improving strength in all muscle groups of the hips and knee, targeting especially the quadriceps. The most tiring exercises for him were supine straight leg raises and wall squat holds since his right quadriceps was still not working at full capacity. These were both added to his HEP. Other strengthening interventions included step training and the double leg press. We also worked on balance and strength simultaneously with mini squats and heel raises on the TRX machine.

Although Don's knee range of motion was much better, he still lacked several degrees of knee flexion and had a little extensor lag. To address this, we had him do some heel slides and quad sets before measuring range of motion, then remeasured after doing some anterior and posterior tibiofemoral joint mobilizations, followed by some chair scoots. These improved his range of motion by at least a few degrees. To decrease his extensor lag, we gave him exercises including prone and standing terminal knee extension. At about the fourth week, we transitioned him from the NuStep to the upright bike. At first, he could only do half revolutions, but as his range of motion improved, he was able to complete a full circle by the time I left. In my time spent here, I feel that Don definitely made gains in strength and range of motion, but he still had yet to improve these areas and his single leg balance.

From this experience, I learned that even people with the same diagnosis may have different functional limitations and require different interventions to get them back to their normal. As a result, it may take some longer than others to fully recover. Until I worked with Don, I had not used NMES on another patient with a total knee replacement, even though this population made up most of my caseload. In addition, patient motivation and self-sufficiency in physical determines success more than the limitations. I have dealt with patients on both sides of the spectrum. Some, like Don, were motivated by the prospect of being able to return to an enjoyable activity, while others came to therapy to "feel good," defeating its purpose. For this population, I would emphasize more range of motion over strengthening earlier on. With that said, decreased strength and balance are just as important. In some sessions, I felt I overemphasized range of motion in the later stage, leading to decreased time spent on strength and balance activities. In addition, I feel that due to poor time management, I didn't always have enough time to give him his home exercises when I felt he was ready. As a result, he wouldn't get some of them until the next session. I feel he would have had more overall improvements sooner had I been more efficient. One suggestion my clinical instructor made was making home exercise programs for certain pathologies. Going forward, being more prepared going into treatment sessions and making sure patients have the information they need will be the most helpful for me.