A tibial tubercle transfer (TTT) is a bone procedure—an osteotomy of the tibial tubercle (Fig. 20.1B). Due to the more extensive pathology and more invasive nature of a distal realignment, or TTT, the patient will have restricted weight bearing. Once the bone has healed and patients are fully weight bearing and functioning pain free, their progression is criterion-based and individualized, much like the patient with an MPFLR. These patients are about 6 weeks behind those status post isolated MPFLR in the earlier stages due to the restricted weight bearing. This will delay the introduction of postural stability, neuromuscular (NM) control, quadriceps strengthening, and, obviously, gait training.
The following guidelines and time frames are based on an isolated MPFLR. Please note the different time frames for an MPFL (Appendix 1) versus a TTT (Appendix 2). The presence of underlying or concomitant pathology will lengthen the rehabilitation process for these patients.
Build a Foundation
The individual can work toward building a foundation of muscular balance prior to surgery. Emphasis will be on the core, the pelvis, hips, and quadriceps and can include postural retraining, soft tissue lengthening, progressive strengthening, and NM control. With chronic dislocators, this is achieved with a home exercise program (HEP) and/or working with a performance coach. In the case of the acute traumatic dislocator, the goal of physical therapy (PT) is to prepare the knee for surgery: control effusion, regain quadriceps function, regain full ROM, and normalize gait.
Set Realistic Expectations
Prepare the patient for the road ahead. The course of rehabilitation, with emphasis on progression of function, is discussed with the patient. If a patient is not seen preoperatively, this should be done at the initial evaluation postoperatively.
Patients tend to be more compliant and less frustrated when they understand what to expect. Realistic expectations are outlined regarding ambulation/crutches, brace, pain, activity modification, exercise progression, function, PT visits, and the patient’s goals. Ballpark time frames are discussed in the context of criterion-based progression.
Gait/Ambulation
The first inquiries we hear from the patient are related to crutches and the brace: When will I be off crutches? How long will I have to wear this brace? In the athletic individual, the first question is when can I play again?
Following MPFLR, the patient will be weight bearing as tolerated (WBAT) with the brace locked in extension for the initial 4 to 6 weeks. After 2 to 3 weeks, the patient may be ambulating without crutches as long as the knee is tolerating the load. This is determined by the absence of active swelling, well-controlled pain, return of quadriceps contraction, and progression of range of motion (ROM). With progression of quadriceps strength and NM control at the knee, the brace will be unlocked from 0 to 60 degrees at a minimum depending on the available ROM (with increased knee flexion ROM, the brace will be opened to a greater degree); however, the patient will be returned to crutches WBAT when the brace is unlocked to help foster a normal gait pattern. Always confirm weight bearing and ROM restrictions with the surgeon because they might change based on graft choice and/or surgeon preference.
Following TTT, the patient will be non–weight bearing or toe-touch weight bearing (TTWB)—depending on the surgeon’s preference—with the brace locked in extension for the initial 6 weeks. Radiographs at 6 weeks will guide the progression of weight bearing with crutches and the brace locked in extension over the course of the next 2 to 3 weeks (equals 8 weeks postoperatively). The progression of weight bearing will be guided by the surgeon. The knee’s tolerance to weight bearing is monitored. During weeks 9 and 10, the patient ambulates full weight bearing (FWB) with the brace locked in extension, devoid of an assistive device. Crutches are reintroduced when the brace is unlocked at week 11 and are used WBAT until the patient demonstrates the ability to achieve full knee extension at heel strike and tolerate adequate knee flexion and weight bearing during the loading response.
Cryotherapy
The patient is encouraged to continue to use cryotherapy throughout the rehabilitation process as the level of activity continues to change.
Activity Modification
The patient’s activity level will be guided by the knee’s tolerance, not the patient’s tolerance, to activity. This is determined by pain, swelling, ROM progression, and quadriceps function.
Therapy Visits
How many times a week do I have to come to therapy? PT visits must be managed. In this school-age population, use all resources available to the patient: the school athletic trainer, the school nurse, and school equipment.
Therapeutic Exercise
Exercise is discussed as it relates to functional progression and activity level. Progression will be based on the return of muscle balance and strategy of movement. Emphasis is on quality of movement: movement strategy, alignment, symmetry, and control.
PHASE I: PROTECTION PHASE (WEEKS 0 TO 6)
The stage is set for the rehabilitation process in this initial 6 weeks. Postoperative treatment includes a home-based program of a continuous passive motion (CPM) machine, quadriceps setting with neuromuscular electrical stimulation (NMES), and cryotherapy. Following TTT, a bone stimulator will be added to the home program. The goals of controlling pain and effusion, minimizing quadriceps inhibition, regaining knee ROM, and patellar mobility are interrelated. The patient is seen once during this phase at 3 to 4 weeks for an ROM check and progression of the HEP to include ROM in the seated position, quadriceps setting, straight-leg raise (SLR) series as tolerated—pain-free SLR in supine (with brace or without brace), hip abduction in side lying or prone, and hip extension in prone; heel raises (MPFLR) or plantarflexion with resistance bands (TTT); and gastrocnemius stretching. If ROM is less than 90 degrees, then formal PT is continued. If ROM is 90 degrees with a good end feel, then the patient continues with a home-based program until the 6-week mark.
Cryotherapy
Even minimal quadriceps effusion has been shown to inhibit quadriceps function. After dextrose saline was injected at 50 mm Hg into nonpathologic knees, quadriceps peak torque, muscle fiber conduction velocity, and root mean square of electromyography (EMG) signals of the vastus medialis were significantly decreased. After 20 minutes of ice application, quadriceps torque and muscle fiber conduction velocity significantly increased as compared to controls.3 Joint effusion can lead to increased pain and decreased ROM, so it is imperative that patients use cryotherapy immediately and often postoperatively.
Gait/Ambulation
The patient is in a brace locked in extension with an appropriate assistive device: WBAT following MPFLR and NWB following TTT.
Therapeutic Exercise
Balance and Proprioception
Weight shifting onto the operative side can be introduced with the brace locked in extension for the MPFLR patient.
Strength
Quadriceps: NMES is used for quadriceps reeducation to abate loss of quadriceps strength and control. Most research with NMES has been done with patients after ACL reconstruction but the same benefits are observed clinically.4
Patients are instructed in quad sets over a towel roll both with and without NMES. The use of the towel roll provides tactile feedback and minimizes fat pad irritation. The goal is to do a pain-free SLR with no lag by the end of this phase. When that is accomplished, they have demonstrated enough quad control to ambulate with brace unlocked.
Proximal and Distal: Evaluation-based gluteal strengthening is initiated. The patient can begin NWB hip strengthening including abduction while standing on the contralateral leg, then progress to side-lying hip abduction against gravity.5 Distal strengthening is initiated to address weaknesses and prepare for push-off.
Range of Motion
The MPFL tightens in early to midflexion and then slackens during deeper flexion after 60 degrees.6,7 A CPM is used 2 to 3 hours per day or 6 to 8 hours with a concomitant cartilage procedure. If a joint is immobilized too long, there will be a loss of ground substance and dehydration in the extracellular matrix, leading to approximation of the fibers.8,9 This approximation causes friction and the formation of adhesions. Active and passive ROM at the knee joint will reverse damaging effects of immobilization by stimulating collagen synthesis and optimizing the alignment of healing tissues.
Patients begin seated at the edge of the plinth for active–assistive range of motion (AAROM) into knee flexion. They then use the contralateral leg for passive knee extension to avoid open chain knee extension early on with quadriceps weakness and especially with cartilage injury. Communication with the surgeon is imperative in this phase if knee flexion is not progressing.
A loss of passive extension is not often seen, but full extension must be maintained via gastrocnemius and hamstring stretching and intermittent heel prop so an antalgic gait on a flexed knee does not occur.
Passive patellar mobility is assessed postoperatively to make sure there is appropriate mobility and end point. The quadrant system10 can be used for assessment, as the contralateral leg may not be a good reference if bilateral hypermobility is present. Patients will sometimes demonstrate apprehension with this due to a history of instability.
Precautions
Patellar mobilization in the lateral direction is avoided in this early phase to allow for healing; however, it is evaluated by the physical therapist to get a sense of its end point. Be cautious not to load the knee with slight knee flexion, as this is the ROM that the MPFL is most vulnerable because there is no bony stability offered by the trochlea. Following TTT, the patient must obey the restricted weight bearing because this is a bony procedure and complications are related to fixation and possible fracture through the osteotomy or screw holes.
Troubleshooting
In the first few visits, get a sense of the progression of knee flexion ROM to avoid postoperative stiffness. Reasons for stiffness after MPFLR include chondral injuries, femoral tunnel malpositioning, improper graft tensioning, excessive pain, or noncompliance with PT.11,12
The goal is to foster a normalized gait pattern. The hallmark of this phase is NM control, alignment, and postural stability in single limb stance.
Control Symptoms
Monitoring the knee for active swelling and pain with resultant loss of motion and quadriceps function is necessary, as the patient’s activity level usually increases during this phase. Staying within his or her envelope of function is continually reinforced.
Standing Posture
Postural retraining with a neutral pelvis with sternal lift and soft knees with symmetrical weight bearing is reinforced throughout the day. (A simple reminder of postural checks when “texting” with friends.) Weight bearing through one hip only is discouraged as is hanging on ligaments with recurvatum in double-limb weight bearing.
Gait/Ambulation
Gait training is performed with an assistive device, or on a hydro-treadmill (with adequate wound healing) or antigravity treadmill, if available. During this time, a normal gait pattern is emphasized:
• Full knee extension at heel strike. Without active knee extension ROM to 0 degree, the individual will not achieve full knee extension during heel strike and will walk with a bent knee gait. This will continually load the extensor mechanism and result in anterior knee pain.
• Adequate knee flexion during loading response. Inadequate NM/eccentric control at the knee and/or pain will not allow the knee to go from knee extension to slight knee flexion during the loading response, resulting in knee extension with sinking into the hip during the loading response. This will, in essence, make the stance leg longer and lead to hip adduction and lengthening of the abductors with resultant weakness (Fig. 20.2). This gait pattern is one of quad avoidance and is often present preoperatively. It will continue postoperatively if not addressed and is often present on the contralateral limb. Decreased shock absorption is a consequence which then leads to increased loading at the tibiofemoral joint and progressive deterioration.13
