Postoperative Management of Patients with Articular Cartilage Repair
The postoperative management of articular cartilage repairs in the knee is key to the continued quality of life for the patient. Because of tissue vulnerability following articular cartilage repair, it is vital that a structured program including early, controlled motion and weight bearing be utilized appropriately to promote an optimal healing environment.1–6 When used appropriately, the early motion and exercise promoted by postoperative rehabilitation can support maturation of the tissue via the principle of mechanotransduction (process by which the body translates a mechanical load into a cellular response).7
Through various animal, cadaver, and human studies it has been determined that mechanotransduction may be thought of as a three-step process: mechanocoupling, cell-to-cell communication, and the effector cell response. Mechanocoupling refers to the process of the physical perturbation to a cell that occurs during a mechanical load and leads to a variety of chemical responses/signals within the cell. On a gross cellular level, the result is cell-to-cell communication, meaning that even those more distant cells that do not receive the direct load will have a response. Finally, the effector cell response refers to the overall result of the mechanotransduction process: cell remodeling and healing. For articular cartilage, it is now well accepted that this creates a healing environment that helps to stimulate matrix production, thus leading to stronger and healthier tissue.5–7
It is essential to facilitate healing while avoiding the potentially deleterious effects of overloading or overstraining developing tissues. For any articular cartilage repair, the rate of progression, amount of range of motion (ROM) desired/allowable, and the amount of weight bearing will all depend on the physiological healing process of the repair in question. This chapter will focus on describing the most current evidence-based rehabilitation for patients who have undergone an articular cartilage repair of the knee. We will also address the issues of postoperative pain management, evaluation for readiness to progress, and potential complicating factors.
Rehabilitation for Articular Cartilage Repairs
Articular cartilage lesions (and thus repairs) vary greatly in size and severity. Thus, the rehabilitative process must take into consideration the size and location of the lesion, as well as type of repair performed. Regardless of the type of cartilage repair, there are several general principles that must be kept in mind to maximize the efficacy of therapy.
Most current protocols call for patients to begin passive motion within hours of undergoing surgery and for 6 to 8 hours per day. Some studies indicate that early motion can promote the formation of the smooth, low-friction surface desired for articular cartilage, while other authors opine that it is helpful in preventing the formation of adhesions.2,3,5,6 Still other authors state that early motion is neither helpful nor harmful.8,9 If used, it is important that early motion be passive and within a restricted range to prevent shearing forces associated with muscle activation that could compromise the repair.
All patients should be introduced to controlled, early, partial weight bearing. Studies show that controlled loading/unloading nourishes developing cartilage in addition to promoting the formation of a stronger matrix in response to the loads, thus leading to tissue with improved mechanical properties. Unloading technology (unloading tread-mills, unloaded squats or leg presses, water therapy) can be helpful in achieving this goal. Attention should also be directed to retraining of the quadriceps and hip flexors, which can be inhibited by postoperative swelling and pain.1,3,10–12
Finally, all programs should include a focus on prevention of soft tissue adhesions. Scar tissue and patellar mobilization should occur early and often, and special attention should be paid to muscle length during the early healing phases.12
The rehabilitation protocols for various procedures are very similar. While it is important to understand the differences in procedures to help assess stages of tissue healing, the variation of protocol generally relates more to the location of the defect, as opposed to the type of procedure performed. Defects within the trochlea are treated a little differently than defects on the femoral condyles, and the rehabilitation is adjusted accordingly. As with any protocol, these are guidelines to follow, but each patient is progressed to the next phase only when appropriate. For example, poor quad strength may prolong time spent in the brace and delay progression to more aggressive strengthening exercises.
Rehabilitation Protocol for Articular Cartilage Repairs
0 to 6 Weeks
Weight-Bearing Status
Trochlear Defect Patients may begin weight bearing as tolerated with brace locked in full extension for 0 to 6 weeks.
Femoral Condyle Defect Patients may begin non–weightbearing with brace locked in full extension for 0 to 4 weeks, then touch weight-bearing with brace unlocked for weeks 5 to 6.
Bracing
Trochlear Defect Brace locked in full extension except when performing ROM exercises. Brace may also be removed for all exercises if patient has appropriate quad control.
Femoral Condyle Defect Brace locked in full extension for 0 to 4 weeks except when performing ROM exercises. Brace may also be removed for all exercises if patient has appropriate quad control. Brace is unlocked for 5 to 6 weeks.
Range of Motion
Femoral Condyle and Trochlear Defects Treated the Same Patients may advance to 90 degrees of flexion as tolerated for weeks 0 to 4; progress to passive range of motion (PROM) as tolerated for weeks 5 to 6; and no active extension through long arc or short arc.
Therapeutic Exercise
Femoral Condyle and Trochlear Defects Treated the Same Following exercises should be performed in brace if quad control is not adequate:
Isometric quad strengthening
Patellar mobilizations
Straight-leg raises
Hip abduction/adduction
Hamstring isometrics
ROM
Stationary bike—only if done passively on involved leg
Core strengthening—not involving postoperative knee
Modalities as needed for pain contro
6 to 12 Weeks
Weight-Bearing Status
Trochlear Defect Patients may continue weight bearing as tolerated and discard crutch as gait normalizes (no antalgic or abnormal gait pattern).
Femoral Condyle Defect Patient may advance to full weight bearing as tolerated and may discard crutch as gait normalizes (no antalgic or abnormal gait pattern).
Bracing
Femoral Condyle and Trochlear Defects Treated the Same Patient may discontinue use of brace upon demonstrating good quad control (can perform straight-leg raise without a lag).
ROM
Femoral Condyle and Trochlear Defects Treated the Same Patient may achieve full active and passive ROM.
Therapeutic Exercise
Femoral Condyle and Trochlear Defects Treated the Same Following exercises should be performed in brace if quad control is not adequate:
ROM to gain full flexion.
Advance stationary bike beyond passive ROM, begin light resistance.
Begin bilateral closed chain activities with resistance less than patient′s body weight through pain-free ROM (no unilateral/single leg dynamic weight-bearing activities).
Initiate proprioception exercises.
Initiate progressive resistive exercises for hamstrings, hips, and lower legs.
Initiate gait training to normalize gait pattern if needed.
Advance core strengthening
12 Weeks and Beyond
Therapeutic Exercise
Femoral Condyle and Trochlear Defects Treated the Same Patients should be full weight bearing with a normal gait pattern. They should be out of the brace and have full passive and active ROM. The following exercises can be performed:
More vigorous treadmill walking
Progression on stationary bike
Stairmaster and elliptical as tolerated
Unilateral balance/proprioception activities
Closed chain activities progressing to resistance greater than the body weight as tolerated
Unilateral closed chain/dynamic exercises (month 4)
Jogging, plyometrics, and sport-specific function training (month 6
Related posts:
Clinical Outcomes Assessment for Articular Cartilage Restoration
Postoperative Management of Patients with Articular Cartilage Repair
Biomechanical Outcomes of Cartilage Repair of the Knee
Magnetic Resonance Imaging of Cartilage Repair Techniques
ACI and MACI
Particulated Articular Cartilage: CAIS and DeNovo NT
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