Explain the impact that biologic healing rates have on postoperative or postinjury rehabilitation programs.
Explain how various biologic variables and functional parameters affect the progression of rehabilitation for knee injuries.
Discuss how surgical techniques that are directed at repairing or reconstructing injured tissues affect the progression of rehabilitation.
Apply the principles gleaned from review of two knee injury treatment pathways to develop other treatment pathways for various pathologies.
Treatment guidelines or pathways based on the best available evidence provide several advantages. First, they help us choose the right care for most patients. Second, they allow us to distinguish those who need more hands-on care and those who can manage their condition themselves. Finally, they allow acceleration of the transition from novice to expert clinician. The aim of this chapter is to describe the development of treatment pathways that ensure the highest probability of success in advancing an athlete from injury back to sport. The knee will be used as an example in this chapter.
Rehabilitation specialists strive to resolve impairments (range of motion, weakness, inflammation) as quickly as possible. We coined the term procedure -(e.g., surgery) modified rehabilitation to underscore the concept that the speed, volume, and intensity of rehabilitation are dependent on the surgical procedure. Not all tissue is of good quality, and not all fixation is rigid. Therefore, adjustments in protocol are necessary to protect the surgical site until biologic healing has progressed to permit the demands of a rehabilitation program. We coined the term rehabilitation-modified surgery to describe the mindset of a surgeon who is willing to spend the extra time to better fix a pathologic structure and thereby allow more timely advancement to return to functional activities. This chapter concentrates on the process of developing postoperative treatment guidelines. First, common knee diagnoses that require surgical intervention are described. For each diagnosis, the primary and associated pathologies are discussed. The indications for surgery, the primary surgical procedure, and the associated surgeries are explained. Critical surgical decisions, extra intraoperative measures taken to allow accelerated rehabilitation (i.e., rehabilitation-modified surgery), and intraoperative and postoperative surgical concerns are discussed. All is presented in the context of what the clinician needs to create and modify in regard to the rehabilitation pathways.
Ultimately, success is a race between biologic healing and failure of fixation. In the knee, pathology involves healing of soft tissue, bone, and articular cartilage. All soft tissue healing is not created equal. Both the quality of the injured tissue and its intrinsic healing potential determine the timing and magnitude of the stress applied to the healing structures (e.g., functional activities, exercises, mobilization). Surgical repair is restricted to structures with healing potential. Repair restores normal anatomy (e.g., suturing an injured structure back together). When healing potential is limited, either because of the inherent properties of the tissues involved (e.g., anterior cruciate ligament [ACL]) or because the extent of the injury is too great (e.g., complex tear of the meniscus), repair is unlikely to be successful even with significantly modified rehabilitation. Repair in this instance would be a failure for the surgeon, the rehabilitation specialist, and most importantly, the patient; therefore, the structure must be resected (removed) or reconstructed (replaced). Resection of pathology is rarely without consequence, and thus reconstruction is preferred whenever possible.
Soft tissue healing potential varies from tissue to tissue—meniscus versus ligament/tendon, intraarticular versus extraarticular, allograft versus autograft. Menisci have good healing potential limited to the periphery, they hold sutures well, but repairs are technically difficult. Tendons (e.g., patellar tendon) have excellent healing potential but tear in a nonuniform manner that demands the use of special suturing techniques to allow the ends to be approximated without pulling through the tissue until biologic healing takes place. Extraarticular ligaments (e.g., medial collateral ligament [MCL]) have excellent healing potential and a good environment for healing but present the same dilemmas and require the same protection as tendons. Surgical repair makes a grade III ligament sprain only a grade II sprain. Surgeons constantly struggle to achieve appropriate tightness without constraining the joint and resulting in loss of motion or increased articular stress. Intraarticular ligaments have a poor blood supply and a hostile environment for healing; consequently, successful repair is rarely possible and reconstruction is the norm. Allograft tissue poses special problems. Although rejection and infection are exceedingly rare, incorporation can be slower than occurs with analogous autograft tissue (i.e., allograft bone heals more slowly than autogenous bone graft).
Healing of bone in the knee is generally good and nonunion is rare. Therefore, surgical procedures in the knee that depend on bone healing for success have predictably good results (e.g., bone–patellar tendon–bone ACL reconstruction), although healing of bone does require a healthy bone base.
Articular (hyaline) cartilage does not have a blood supply and its healing potential is limited. Normally, articular cartilage defects heal with the formation of fibrocartilage, but new techniques for cartilage repair boast of healing with hyaline cartilage (e.g., autologous chondrocyte implantation).
With repair and reconstruction, the concepts of fixation become critical to the timing of progression of the rehabilitation program. Rigid fixation is optimal but unusual. It implies that the fixed structure can withstand normal forces without protection. Other than fractures and bone–patellar tendon–bone autografts, rigid fixation is most times an unrealizable ideal. Most knee surgeons seek to achieve semirigid fixation. Soft tissue screws have enhanced surgical procedures that require ingrowth of bone into soft tissue. Techniques to hold the graft firmly in place (though not strictly providing rigid fixation) are being advanced by surgeons and orthopedic implant manufacturers around the world. Soft tissue fixation always depends on the inherent biologic healing potential of the injured tissue and the individual patient variables (e.g., age, diabetes, peripheral vascular disease). When fixation is possible only with sutures, both the surgery and the rehabilitation are at major risk of losing the race between biologic healing and failure of fixation.
The addition of tension bands to protect the primary quadriceps or patellar tendon repair is the classic rehabilitation-modified surgery. Band sutures are used to pull the tissues closer to the patella as the knee flexes, thereby protecting the repair sutures while allowing flexion to 120°. Like most rehabilitation-modified surgery, it is more time-consuming, with an additional 10 minutes being needed.
In addition to the inherent healing potential of each tissue, the injury itself has an impact on healing. Many studies of healing in animals models (see Chapter 2 ), on which our estimates of healing have traditionally been based, involved cutting of structures (e.g., clean cuts) in otherwise healthy, young animals. This represents the ideal situation but is seldom found in the operating room. The tissue encountered is often degenerated, stretched, macerated, or torn at different levels (e.g., “mop end”). In addition, concomitant illness or injury and age affect healing. Healing rates of tissues are typically described as ranges ( Fig. 3-1 ). The development and implementation of contemporary evidence-based rehabilitation protocols are predicated on the rehabilitation specialist’s knowledge of these time frames and moderators.
All rehabilitation practice guidelines included in this chapter are criterion based. The criteria for progression are similar for each. Pain and swelling are the main indicators that the rehabilitation is progressing too quickly. In addition, quadriceps strength and inhibition and the results of performance on functional tests and self-report questionnaires are used to gauge progress and readiness ( Box 3-1 ).
Use validated performance measures.
Monitor pain, swelling, and fatigue.
Know tissue-healing time frames.
Follow the soreness rules.
We have developed and previously reported the use of soreness rules for functional progression in individuals with a variety of pathologic conditions. Soreness is defined as soreness of the involved structure (e.g., knee joint, not the quadriceps muscle). These guidelines are presented in Box 3-2 .
If no soreness is present from the previous day’s exercise, advance the level of exercise by modifying one variable.
If soreness is present from the previous day’s exercise but recedes with warm-up, stay at the same level.
If soreness is present from the previous day’s exercise but does not recede with warm-up, decrease exercise to the level before progression. Consider taking the day off if soreness is still present with the reduced level of exercise. When exercise is resumed, it should be at the reduced level.
Knee effusion is an indicator of healing and response to treatment progression. Careful assessment of effusion is necessary for effective implementation of progressive rehabilitation. Girth measurements do not adequately quantify effusion, particularly if the effusion is small. Instead, the stroke test can give more meaningful information about the presence and amount of effusion. The stroke test is performed with the patient supine and the knee relaxed in full extension. The test starts with the examiner performing several strokes upward from the medial joint line toward the suprapatellar pouch in an attempt to move the effusion from the medial aspect of the knee. The examiner then strokes downward on the lateral side of the knee from the suprapatellar pouch toward the lateral joint line and observes the medial aspect of the knee in an effort to appreciate a fluid wave emanating from the suprapatellar pouch ( Fig. 3-2 ). Four different grades are used to describe the amount of effusion. If no wave is produced with the downward stroke, no effusion is present. If the downward stroke produces a small wave on the medial side of the knee, the effusion is given a “trace” grade; a larger bulge is given a “1+” grade. If the effusion returns to the medial side of the knee without a downward stroke, the effusion is given a “2+” grade. Inability to move the effusion out of the medial aspect of the knee equates to a “3+” grade ( Table 3-1 ). The reliability of this test is excellent.
|Zero||No wave produced with a downstroke|
|Trace||Small wave on the medial side with a downstroke|
|1+||Larger bulge on the medial side with a downstroke|
|2+||Effusion spontaneously returns to the medial side after an upstroke (no downstroke necessary)|
|3+||So much fluid that it is not possible to move the effusion out of the medial aspect of the knee|
Quadriceps Strength Testing
Quadriceps weakness is common after a knee injury; therefore, measurement of quadriceps strength is important to ensure full resolution of this impairment before return to sport. Biomechanical studies have demonstrated that a deficit in quadriceps strength is correlated with altered gait.
A variety of methods can be used to test quadriceps strength. The two most common methods used in the clinical setting are manual muscle testing and isokinetic testing (see Chapter 25 ). Manual muscle testing is one of the easiest to use; however, the results are less accurate when a patient is able to generate high force or when the difference in strength between limbs is minimal. Isokinetic testing offers the benefit of objective measurement through a force transducer, but the most clinically significant testing speed has not been established. Faster speeds better approximate the speed of joint motion during function; however, they underestimate deficits in strength.
Neither manual muscle testing nor isokinetic testing measures a patient’s effort or offers a method to quantify quadriceps inhibition (inability to fully activate the quadriceps voluntarily). The quadriceps can be inhibited following a knee injury. The burst superimposition method of testing quadriceps strength is not used as commonly in the clinical setting as in research studies, but this method offers the ability to measure inhibition. For this type of testing, an electrical stimulus is applied (superimposed) while the patient produces a maximum voluntary isometric contraction. If the patient has fully activated the quadriceps, no force augmentation will occur when the electrical stimulus is delivered. Up to 5% inhibition is considered normal. If the burst superimposition method of testing is not available to the clinician, targets should be set and verbal encouragement given during testing to improve the quality of the effort.
In sports rehabilitation, hop testing is a commonly used clinical test of function. Many clinics use one or all of the hop tests described by Noyes et al, which include the single-hop test, triple-hop test, crossover triple-hop test, and timed hop test. Testing in an uninjured population showed that 92% to 93% had a symmetry index (side-to-side comparison) of at least 85% for the single-hop and timed hop tests ; thus, a score of less than 85% on the hop tests can be indicative of disability. Hop testing has good reliability, particularly when patients are given more than one practice trial. See Chapter 22 for more on functional testing.
Other Functional Measures
In patients who are older and not athletes, other functional tests can provide insight into functional progression. Tests such as the Timed-Up-and-Go (TUG), Functional Stair Test (FST), and 6-minute walk have been used for the evaluation of patients recovering from knee surgery, typically for those with osteoarthritis. The first two are timed tests and the last is a walking distance measure. The TUG test is a measure of the ability to rise from a chair, walk 3 m, and return to sit in the chair. The FST is a timed measure of the ability to ascend and descend a flight of stairs. The 6-minute walk measures the distance that an individual can walk in 6 minutes with unrestricted rest times.
The use of self-report questionnaires to measure health-related quality of life and self-assessment of function is helpful in assessing the progress of rehabilitation after knee surgery. In our clinic a generic health status index is typically used, the Medical Outcomes Trust SF-36, as well as a regional (knee-specific) health status index, the Knee Outcome Survey (KOS). The KOS has two forms, the Activities of Daily Living Scale and the Sports Activity Scale.
Progression of aerobic conditioning often includes a running program that is usually initiated in this phase of rehabilitation. To start running, quadriceps strength on the athlete’s injured side must be restored to at least 80% of that on the uninvolved side, and sufficient healing of the injured structure must have occurred (e.g., ACL reconstruction at approximately 8 weeks, grade I MCL injury at 1 to 2 weeks). Soft tissue healing is generally sufficient at 4 to 6 weeks. Running progression starts on a treadmill and then moves to running on a track. Track workouts are initiated by running the straightaways and walking the corners. The intensity is gradually increased until the athlete can run the full length of the track. Road running and finally off-road running represent the least controlled training situations and are instituted as a final stage in running progression. Jogging duration may start with as much as 2 miles and may be progressed on a weekly basis if no pain or swelling occurs. Completion of a full running progression can take as long as 2 to 3 months.