Principles of Rehabilitation
Kevin E. Wilk, Michael M. Reinold, and Adam C. Olsen
In This Chapter
Creating a healing environment
Decreasing pain and effusion
Preventing deleterious effects of immobilization
Retarding muscle atrophy
Muscle strength and endurance
Soft tissue flexibility and mobility
Entire kinetic chain
Return to functional activities
PRINCIPLES OF REHABILITATION
Successful rehabilitation begins with communication among the sports medicine team and the establishment of an accurate and differential diagnosis. The key to successful rehabilitation is communication; to facilitate this interaction, the physician and rehabilitation specialist must communicate, providing information regarding the type of injury or surgical procedure performed, method of surgical fixation, the results of any diagnostic tests, the integrity and quality of the patient's tissue, and the expectations of the physician for that specific patient. This information is invaluable to the rehabilitation specialist in designing and implementing a rehabilitation program.
The rehabilitation specialist must also perform a thorough and systematic physical examination to determine specific functional impairments, such as loss of motion or decreased strength of involved joints or muscles. Furthermore, the rehabilitation specialist must identify all involved structures that may be contributing to the patient's loss of motion, such as a tight joint capsule or muscular tightness. To obtain a successful outcome, the rehabilitation specialist must identify and treat the causes of the dysfunction. Then a thorough rehabilitation program can be outlined to address the individual diagnosis and functional needs of the athlete. It is imperative that the rehabilitation program be individualized based on each patient's unique response to injury.
For a patient to progress from one rehabilitation phase to the next, he or she must fulfill specific criteria. This progression allows the program to be individualized, based on the patient's unique healing rate and constraints. Programs are oftentimes broken up into phases such as acute postoperative phase or advanced strengthening phase, designed to emphasize goals that are specific to the proper time frame of tissue healing at that particular point in rehabilitation. Each phase has its unique goals that must be met in order to progress to the next phase, such as restoring full range of motion (ROM) or normalizing arthrokinematics. Each patient may reach these milestones at different times, which promotes a criteria-based rather than a time-based progression. The progression also helps to assist in locating areas in which the patient may be improving slowly and may need additional attention.
A fundamental concept that we use in developing a rehabilitation program at our center is to establish a differential diagnosis from the involved structures and causes contributing to the lesion. An example could be subacromial impingement. The cause of subacromial impingement is multifaceted.1 Some possible causes are capsular tightness, capsular hypermobility, scapular position, and rotator cuff imbalances. To successfully treat this specific diagnosis, the rehabilitation specialist must treat the causes of the problem, thus normalizing joint function.
The basis for all rehabilitation programs is to facilitate healing. It is imperative that the clinician promote healing but must be careful not to overstress the healing tissue. This first principle involves not just the facilitation of healing but also avoidance of excessive stresses that may be disadvantageous for tissue healing throughout the rehabilitation process. This may be illus
• Rehabilitation is a multifaceted and ever-evolving process based on the basic science and general principles of tissue healing.
• The rehabilitation specialist must integrate the clinical diagnosis from the medical team with a full functional examination of the musculoskeletal system.
• The goal of rehabilitation is to enhance the recovery of injured tissues while avoiding stresses that may prove deleterious to the healing process. This is accomplished through a thorough understanding of the normal function, pathomechanics, and healing process of the specific tissue involved.
• The rehabilitation specialist must use current research and scientific evidence to establish guidelines to facilitate this process.
• In this chapter, we overview the most current evidence-based principles of rehabilitation with emphasis on clinical implication for sports medicine patients. The primary goal of this chapter is to discuss current concepts in rehabilitation.
trated in the rehabilitation of articular cartilage lesions. Controlled motion and gradual weight bearing progression is necessary to stimulate the healing process but must be progressed cautiously so that disadvantageous forces are not applied that will overload the tissue and inhibit healing. Thus, the program must be progressive and sequential, with each phase building from the previous one. Attempting to have a patient progress too quickly may result in inflammation, soreness, and potentially tissue failure, whereas the controlled application of specific stresses can benefit healing tissues. Another example of this is the rehabilitation of the anterior cruciate ligament (ACL) reconstruction patient. The graft must undergo revascularization as well as tissue remodeling before strenuous activities are allowed.
The first specific goal in most rehabilitation plans is to decrease the patient's pain and effusion resulting from the injury or pathology. Swelling at the injury site can stimulate sensory nerves leading to a further increase in the athlete's perception of pain. Pain and inflammation also work as muscle inhibitors, causing disuse atrophy the longer the effusion is present.
Numerous authors have studied the effect of joint effusion on muscle inhibition. DeAndrade et al2 report that joint distention resulted in quadriceps muscle inhibition. A progressive decrease in quadriceps activity was noted as the knee exhibited increased distention. Spencer et al3 found a similar decrease in quadriceps activation with joint effusion. The authors reported the threshold for inhibition of the vastus medialis to be approximately 20 to 30 mL of joint effusion and 50 to 60 mL for the rectus femoris and vastus lateralis. Similar results have been reported within the literature.4-7
Mangine et al (unpublished data, 1985) measured the peak torque and electromyographic activity of the quadriceps musculature while progressively effusing the knee joint. The authors noted that with the addition of 30 to 40 mL to the knee joint, quadriceps peak torque dramatically decreased by approximately 50% and continued to decrease with added effusion. Also, while the rectus femoris and vastus lateralis demonstrated mild decreases in muscle activity with the addition of joint effusion, the vastus medialis muscle activity decreased dramatically in proportion to the amount of joint effusion added. Vastus medialis oblique activity began to decrease with the addition of 20 mL while the rectus femoris and vastus lateralis required approximately 60 mL before a reduction in muscle activity was noted.
Thus, the reduction in knee joint swelling is crucial to restore normal voluntary quadriceps activity. Treatment options for swelling reduction include elevation, cryotherapy, high-voltage electrical stimulation, and joint compression through the use of a knee sleeve or compression wrap (Fig. 11-1). In patients who have undergone certain procedures for the knee, such as a lateral retinacular release, a foam wedge shaped to form around the lateral patella can be used in conjunction with a wrap to provide increased compression around the lateral genicular artery. Patients presenting with chronic joint effusion may also benefit from a knee sleeve or compression wrap to apply constant pressure while performing everyday activities in an attempt to minimize joint effusion. Conversely, patients with acute inflammation can benefit from ice and elevation.
Pain may also play a role in the inhibition of muscle activity observed with joint effusion. Young et al8 examined the elec-tromyographic activity of the quadriceps in the acutely swollen
and painful knee. An afferent block by local anesthesia was produced intraoperatively during medial meniscectomy. Patients in the control group reported significant pain postoperatively and pronounced inhibition of the quadriceps (30% to 76%). In contrast, patients with local anesthesia reported minimal pain and only mild quadriceps inhibition (5% to 31%). Thus, it appears that muscle inhibition may be attributed to a combination of joint pain and effusion.
Pain can be reduced passively through the use of cryotherapy and analgesic medication. Immediately following injury or surgery, the use of a commercial cold wrap can be extremely beneficial. Passive ROM may also provide neuromodulation of pain during acute or exacerbated conditions. Numerous studies have documented that passive ROM exercises reduce the need for pain medication.9,10 Lastayo et al11 report favorable results when continuous passive motion or manual passive ROM exercises are emphasized following repair of small, medium, or large tears of the rotator cuff. Therapeutic modalities such as ultrasound and electrical stimulation may also be used to control pain via the gate control theory.
The speed of progression of rehabilitation, particularly weight-bearing status and ROM, may also effect pain and swelling. Therefore, any increase in pain or effusion in the involved joint is monitored as the patient progresses through rehabilitation and begins new exercises. This is monitored to ensure that the pace of rehabilitation is appropriate and the tissue is not being overstressed. Persistent pain, inflammation, and swelling may result in long-term complications involving ROM, voluntary quadriceps control, and a delaying of the rehabilitation process; therefore, it is imperative that these symptoms be minimized.
When progressing a patient through rehabilitation, thought must be given to the healing tissue itself. If a patient is progressing ahead of schedule and has no complaints, can he or she continue at an accelerated rate without compromising the long-term health of the tissues? Does an athlete returning to sport at 4
months mean a better outcome than returning at 6 months? Several characteristics must be considered when deciding the appropriate speed of rehabilitation. The patient's age, genetics, nutrition, concomitant injuries, and unique healing characteristics can all affect the rehabilitation time line.12 Injuries to the meniscus or collateral ligaments may require a slower rehabilitation process following ACL reconstruction. Not all concomitant injuries are visible. Several authors13,14 have reported that more than 80% of patients who sustain an acute ACL injury exhibit a bone bruise on magnetic resonance imaging. Johnson et al13 have reported that patients with a bone bruise who underwent ACL reconstruction required a longer period to reduce effusion and pain and to return muscle function. Additional effects may not be seen for years after the initial injury such as articular cartilage lesions and the development of early knee osteoarthritis. Some authors believe that bone bruises resolve in several months,15 whereas others believe the homeostasis of the bone may be altered for much longer16 (Wojtys, unpublished data, 2004). The decisions made during rehabilitation may have significant effects on the metabolic activity of the injury site and the return to normal joint homeostasis.16 Risks of an accelerated rehabilitation must be evaluated for each patient with careful consideration of the possible consequences. The rehabilitation specialist must be very careful when treating bone bruises. We recommend treating them with partial weight bearing, ice, compression, and control of aggressive loading for several months.
PREVENTING THE DELETERIOUS EFFECTS OF IMMOBILIZATION
In the acute stages of healing, it is often necessary to restrict motion of the injured tissues to promote healing (Fig. 11-2). While restricted, strength and muscular girth are quickly lost, and joint contracture and loss of ROM may occur. Furthermore, recent studies have documented that the combination of unloading and immobilization results in significant proteoglycan loss and weakening of the articular cartilage.17,18 The deleterious effects of immobilization must therefore be minimized, and immobilization should be avoided in most cases.
Current research indicates immediate controlled motion is critical to a successful outcome.19-23 Rehabilitation following ACL injury changed dramatically when it was found that patients who were taken through an accelerated program experienced a better outcome, including a decreased incidence of arthrofibrosis and quicker return to activity.23 Immobilization is avoided in rehabilitation, with a greater emphasis on controlled ROM in a protected range. It is the authors' belief that the controlled application of ROM during the early phases of ROM is beneficial to avoid long-term loss of motion and to stimulate the synthesis, organization, and alignment of collagen tissue. Other benefits of early passive ROM include the reduction of pain and swelling, facilitation of a more normal gait pattern, and stimulation of collagen and cartilage repair. Beynnon et al24 have documented with ACL subjects during passive ROM that there is no strain on the ACL with 0 to 125 degrees of motion.
Passive motion is most often performed by a skilled clinician but can also be performed by a continuous passive motion or by an isokinetic device set in the passive ROM setting. The use of continuous passive motion following surgery has several benefits including the avoidance of arthrofibrosis. In a study by Rodrigo et al,25 patients undergoing a microfracture procedure of the knee who performed continuous passive motion for the first 8 weeks demonstrated 85% good to excellent results compared to a group of patients without continuous passive motion, who only had 55% good to excellent results. In the case of patients who underwent rotator cuff repair, restoring passive ROM is critical to the successful outcome of these patients.
RETARDING MUSCULAR ATROPHY
Rehabilitation should also emphasize the retardation of muscular atrophy and the facilitation of volitional muscle activity following an injury or surgical procedure. As previously mentioned, a small increase in pain and/or joint effusion can decrease the voluntary control of surrounding musculature. This can significantly affect the patient's ability to control the limb and ambulate with a normal gait pattern.
Exercises designed to enhance muscular volition begin with basic isometric contractions of the involved muscles. This isometric contraction allows firing of the muscle fibers without joint motion. This is a safe and effective method of exercise during the early phases of rehabilitation. Isometric contractions are performed for each muscle at multiple static angles throughout the available ROM. Isometric contraction has also been shown to be one of the most efficient forms of exercise for increasing muscular tension and improving strength.
Muscle re-education with electrical muscle stimulation (EMS) may assist in restoring the patient's voluntary control of inhibited musculature. EMS is often applied concomitantly during isometric and isotonic exercises to increase the recruitment of muscle fibers during the contraction.
Snyder-Mackler et al26 studied the effects of electrical stimulation on quadriceps muscle strength following ACL reconstruction. Following a comparable 4-week training period, patients exercising with the adjunct of a high-intensity EMS unit exhibited quadriceps strength greater than 70% of the unin-
volved lower extremity. Patients not using EMS presented with quadriceps strength of only 57% of the opposite knee in the same time period following surgery. The authors noted that the addition of neuromuscular electrical stimulation to postoperative exercises resulted in stronger quadriceps and more normal gait patterns than patients exercising without electrical stimulation. Several authors have also reported similar gains while integrating EMS into postoperative rehabilitation programs.26-29
Reinold et al (unpublished data, 2005) recently evaluated the use of EMS of the external rotators in the first 2 weeks following mini-open and arthroscopic rotator cuff repair surgery. The authors measured the amount of voluntary force generation by the patient during an isometric external rotation contraction with and without the application of EMS. Results revealed that patients were able to generate approximately 60% greater force production while using the EMS. This was a significant increase in force with the use of EMS superimposed on the muscular contraction.
Biofeedback may also be used to enhance the voluntary control of the injured musculature. Biofeedback is used to allow the patient to monitor the amount of force production throughout the exercise. Draper and Ballard30 compared the use of EMS to biofeedback in the recovery of quadriceps strength following ACL reconstruction. Rehabilitation began immediately after surgery and continued for the first 6 weeks postoperatively. Both groups produced a significant increase in quadriceps peak torque. The group of patients using biofeedback showed slightly greater peak torque output of the quadriceps than did the group using EMS.
Clinically, we use EMS immediately following injury or surgery while performing isometric and isotonic upper and lower extremity exercises (Fig. 11-3A and B). EMS is used prior to biofeedback when the patient presents acutely with the inability to activate the musculature. Once independent muscle activation is present, biofeedback may be used to facilitate further neuromuscular activation. However, EMS may still be used to recruit more motor units, thus resulting in greater strength gains. Therefore, we use EMS for several weeks (4 to 8 weeks) following ACL surgery or selected shoulder surgeries. Conversely, biofeedback is used for patellofemoral rehabilitation patients when they are unable to actively recruit the vastus medialis (Fig. 11-3C). The patient must concentrate on neuromuscular control to independently activate the muscle during rehabilitation.
GRADUAL RESTORATION OF MUSCULAR STRENGTH AND ENDURANCE
After volitional control of muscle activity is achieved, emphasis is placed on gradually restoring muscular strength. A baseline level of muscular strength is needed before the athlete can progress to the later stages of rehabilitation that include advanced neuromuscular control drills. Strengthening can be performed through a variety of different methods of isotonic exercise. Weight is gradually applied and increased as the athlete progressively improves in strength to ensure that the exercise is constantly challenging. Isotonic exercises are generally performed as either isolated joint movements, such as knee extension, or multijoint movements, such as a squat. Furthermore, exercises can be performed in either an open or closed kinetic chain environment. An open kinetic chain exercise can be defined as a movement where the distal extremity is not fixed, such as knee extension. Conversely, a closed kinetic chain exer cise can be defined as a movement where the distal extremity is fixed, such as the leg press. Each of these modes of exercise have a place in rehabilitation, although all have a different effect on not only muscular activity, but also on the biomechanics of the joint. Wilk and Escamilla31,32 have studied the EMG activity and biomechanical stresses during open and closed kinetic chain exercises for the lower extremities during various conditions. These authors noted that how the exercise is performed can significantly affect the exercise result. For example, during the vertical squat, by increasing the subject's hip flexion, the electromyographic activity of the hamstrings is increased and that of the quadriceps is slightly decreased. By performing a wall squat, the electromyographic activity of the quadriceps is extremely high and that of the hamstrings is lower and significantly different from the vertical squat.
Witvrouw et al33 prospectively studied the efficacy of open and closed kinetic chain exercises during nonoperative patellofemoral rehabilitation. Sixty patients participated in a 5-week exercise program consisting of either open or closed kinetic chain exercises. Subjective pain scores, functional ability, quadriceps and hamstring peak torque, and hamstring, quadriceps, and gastrocnemius flexibility were all recorded prior to and following rehabilitation as well as at 3 months later. Both treatment groups reported a significant decrease in pain, increase in muscle strength, and increase in functional performance at 3 months following intervention.
Muscular endurance is also an important factor to emphasize in rehabilitation programs. Many of the activities that athletes participate in involve repetitive and microtraumatic events. Training the musculature to endure these events is necessary to prevent injuries. Fatigue has been shown to result in decreased proprioception and altered biomechanics of the joints, which may result in further pathology.34-38 Murray et al39 have reported significant changes in throwing mechanics, joint stresses, and velocity during overhead pitching once the thrower has fatigued.
NORMALIZATION OF SOFT-TISSUE MOBILITY AND FLEXIBILITY
Often times in rehabilitation, soft-tissue balance is emphasized. This applies to both the soft tissue around joints, such as the retinacular tissue surrounding the patella, and the muscular flexibility around each joint. Any deviations in the balance of soft-tissue forces will promote altered arthrokinematics and excessive forces to the joints. This can easily be illustrated in the patient with patellofemoral pain who presents with excessive lateral pressure syndrome and clinical signs of patellar tilting and lateral displacement due to tightness of the lateral retinac-ular tissue.
Another example of balancing the soft tissue about a joint is at the glenohumeral joint. Wilk et al40 have referred to this concept as "asymmetrical capsular tightness." This means that if one side of the joint capsule is tight, then the arthrokinematics of the joint will be significantly affected. Thus, if the inferior capsule is tight, then the humeral head will translate superiorly during active arm motions. Harryman et al41 have documented this concept with tightness of the posterior glenohumeral joint.
Muscular flexibility is also vital to normal joint function by allowing the musculature to absorb force and align the joint in a neutral position. For example, soft-tissue tightness of the quadriceps musculature is a common occurrence in patients with patellar tendonitis and patellofemoral pain.
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