Clinical Concepts

A paucity of information exists in the literature concerning rehabilitation after reconstruction of the posterior cruciate ligament (PCL) and posterolateral structures. The posterolateral structures comprise the fibular collateral ligament and popliteus muscle-tendon-ligament unit, including the popliteofibular ligament and posterolateral capsule.

The rehabilitation protocols described in this chapter consist of a careful incorporation of exercise concepts supported by scientific data and clinical experience.^3,14,15,17 The goal is to progress a patient on a rate that takes into account athletic and occupational goals, condition of the articular surfaces and menisci, return of muscle function and lower limb control, postoperative graft healing, and graft remodeling. Modifications to the postoperative exercise program may be required if noteworthy articular cartilage deterioration is found during surgery.

The protocol for PCL reconstruction was developed for a high-strength two-strand graft (quadriceps tendon–bone, bone–patellar tendon–bone). The protocol for posterolateral reconstruction may be used after the various operative options described in detail in Chapter 22, including anatomic and proximal advancement techniques of the posterolateral structures and nonanatomic femoral-fibular reconstruction.

The supervised rehabilitation programs are supplemented with home exercises performed daily. The therapist must routinely examine the patient in the clinic in order to implement and progress the appropriate protocol. Therapeutic procedures and modalities are used as required for successful rehabilitation. For the majority of patients, a range of 11 to 21 postoperative physical therapy visits is expected to produce a desirable result. A few more visits may be required for advanced training between the 6th and the 12th postoperative month for certain patients who desire to return to strenuous activities.

For all patients, joint swelling, pain, gait pattern, knee motion, patellar mobility, muscle strength, and flexibility are continually monitored postoperatively.

Patients are warned to avoid any exercises or activities that place high posterior shear forces on the tibia such as walking down inclines or squatting for the first 6 postoperative months. In addition, patients are cautioned that an early return to strenuous activities postoperatively carries a risk of a repeat injury or the potential of compounding the original injury. These risks cannot always be scientifically predicted, and patients are cautioned to avoid strenuous activities for 9 to 12 postoperative months and to avoid activities that produce pain, swelling, or a feeling of instability. These patients are monitored after surgery with posterior drawer testing and stress radiography if an increase in posterior tibial displacement is detected.

Patients with posterolateral reconstruction are warned specifically at the 4th to 8th postoperative weeks that, with resumption of weight-bearing and weaning of crutches, to avoid a varus or internal tibial rotation position that could place high tensile forces on the posterolateral structures.^13,16 It is important that the patient demonstrates good lower extremity control with suitable muscle strength to maintain tibiofemoral compensation and avoid a lift-off of the lateral tibiofemoral joint, which may disrupt the posterolateral reconstruction.

PCL Clinical Biomechanics

Kaufman and coworkers⁸ used a three-dimensional biomechanical model to predict dynamic patellofemoral and tibiofemoral forces generated during isokinetic exercises at 60°/sec and 180°/sec. During isokinetic extension, posterior shear forces were detected at knee flexion angles of 40° and greater. The maximum posterior shear force occurred at 70° to 80° of knee flexion and measured 0.5 ± 0.1 body weight at 60°/sec and 0.6 ± 0.1 body weight at 180°/sec

A posterior shear force occurred throughout the entire flexion exercise at all knee flexion angles, reaching a peak at 75° of knee flexion of 1.7 ± 0.8 body weight (60°/sec) to 1.4 ± 0.5 body weight (180°/sec). The authors concluded that isokinetic exercise exerted moderate posterior shear forces and should be used cautiously after PCL rupture and reconstruction.

Ohkoshi and associates¹⁹ used a two-dimensional model to calculate shear force exerted on the tibia during standing at various knee flexion angles in 21 healthy subjects. Posterior shear forces were found in the upright position of the trunk and at knee flexion angles of 15° to 90° (Fig. 23-1). At 30° and 60°, the posterior drawer force was significantly increased by anterior flexion of the trunk.

FIGURE 23-1 Calculated shear force (kilograms) per body weight (kilograms) while standing on both legs at various flexion angles of the knee and trunk.

(From Ohkoshi, Y.; Yasuda, K.; Kaneda, K.; et al.: Biomechanical analysis of rehabilitation in the standing position. Am J Sports Med 19:605–611, 1991.)

Castle and colleagues⁴ measured posterior tibial subluxation during a static double-legged squat in patients with PCL-deficient knees. The results revealed a statistically significant mean increase of 5.9 mm in posterior tibial translation (P < .05) of the injured knee compared with the contralateral knee at high knee flexion angles. At low flexion angles, the magnitude of increase in mean posterior tibial translation was only 2.1 mm. Tibiofemoral shear forces were small compared with tibiofemoral joint compression forces.

Berchuck and coworkers² calculated large posterior shear forces during gait analysis for the activities of jogging, ascending stairs, and descending stairs (Fig. 23-2) in five normal subjects. Lutz and associates⁹ evaluated tibiofemoral joint shear and compressive shear forces using a two-dimensional biomechanical model and electromyographic (EMG) activity of hamstrings and quadriceps muscle activity during a closed kinetic chain (CKC) leg press exercise, an isometric open kinetic chain (OKC) exercise, and an OKC flexion exercise. Measurements of maximum muscle contractions were obtained at 30°, 60°, and 90° of knee flexion. The OKC isometric flexion exercise produced posterior shear forces at all knee flexion angles (Fig. 23-3), ranging from –939 ± 174 N at 30° of knee flexion to a maximum of –1780 ± 699 N at 90° of knee flexion. The CKC exercises produced significantly less posterior shear forces at 60° and 90° of flexion (–538 N; P < .05). These findings were similar to those reported by Smidt²¹ during isometric knee extension and flexion exercises (Fig. 23-4). Maximum hamstrings EMG activity was detected during the OKC exercise at 90° of flexion (82 ± 15% of maximum contraction). The antagonistic muscle activity was minimal during this exercise at all knee flexion angles. In contrast, co-contraction of the quadriceps and hamstrings was observed during the CKC exercise, which was greatest at 30° and 60° of flexion. The authors concluded that CKC exercise produced significantly less tibiofemoral shear forces compared with OKC exercise (P < .05).

FIGURE 23-2 Calculated tibiofemoral shear forces during activities.

FIGURE 23-3 Average tibiofemoral shear forces observed during the closed kinetic chain leg press, the open kinetic chain extension, and the open kinetic chain flexion exercise.

(From Lutz, G. E.; Palmitier, R. A.; An, K. N.; Chao, E. Y.: Comparison of tibiofemoral joint forces during open-kinetic-chain and closed-kinetic-chain exercises. J Bone Joint Surg Am 75:732–739, 1993.)

FIGURE 23-4 Calculated tibiofemoral shear forces during isometric knee extension and flexion.

Wilk and colleagues²³ evaluated tibiofemoral shear forces and EMG activity of the quadriceps, hamstrings, and gastrocnemius muscles during OKC extension and CKC leg press and squat exercises. Both CKC exercises produced posterior shear forces. However, during the squat, these forces were relatively low (245–565 N) from 0° to 45° of knee flexion. A rapid increase in posterior shear forces was detected from 45° to 72° of flexion. In addition, co-contraction of the quadriceps and hamstrings occurred from 0° to 30° of flexion. The authors concluded that vertical squats from 0° to 45° of flexion should not be performed in knees in the early stages of PCL reconstruction rehabilitation.

Wilk and colleagues²³ also found that the knee extension exercise produced posterior shear forces from 60° to 100° of knee flexion; however, these forces were lower than those measured during both CKC exercises. The leg press induced minimal hamstring muscle activity.

Hoher and coworkers⁷ reported that the in situ forces in the PCL significantly increased with knee flexion in response to an isolated hamstrings load, reaching a maximum at 90° of flexion. These findings were in agreement with other authors^5,24 who also reported increased strain in the PCL with knee flexion. The addition of a 200-N quadriceps load (simulating co-contraction of the quadriceps and hamstrings) reduced the in situ forces in the PCL.

Toutoungi and associates²² combined noninvasive experimental measurements with geometrical modeling of the lower extremity to calculate ligament forces during isometric, isokinetic, and squat exercises. The data indicated that isokinetic extension at knee flexion angles less than 70° should be safe in the early postoperative period after PCL reconstruction. However, isokinetic flexion and deep squats should be avoided. During isokinetic flexion, only the PCL is loaded and peak forces may reach over 4 times the patient’s body weight at 90° of knee flexion. During squatting, PCL forces may reach 3.5 times body weight at high knee flexion angles. Shallow squats with knee flexion angles kept below 50° may be considered.

Markolf and colleagues¹⁰ studied the effects of muscle loads on cruciate force levels when the knee was subjected to external forces and moments. Load cells were installed into cadaveric knees to record forces in the ACL and PCL under five loading conditions. These force measurements were repeated with a 100-N load applied to the quadriceps tendon and with a combined 50-N load applied to both the biceps and the semimembranosus-semitendinosus tendons.

With no applied tibial force, application of hamstrings load significantly increased mean PCL force from 15° to 120° of knee flexion (Fig. 23-5; P < .05). With the application of a 100-N posterior tibial force, the addition of hamstrings load significantly increased mean PCL force between 30° and 105° of flexion (Fig. 23-6; P < .05). When a 5-Nm external tibial torque was applied, the addition of hamstrings load significantly increased mean PCL force beyond 75° of knee flexion (P < .05). Under a 5-Nm internal tibial torque, application of hamstrings load also significantly increased mean PCL force between 60° and 100° of flexion (P < .05). The authors concluded that, in general, the hamstrings were more effective in producing changes in cruciate force levels. Application of tibial torque in either an anterior or a posterior direction when the knee was flexed greater than 60° increased PCL force, and isolated hamstrings activity (with tibial torque) further increased PCL force.

FIGURE 23-5 Posterior cruciate ligament (PCL) forces from 0°–120° of knee flexion with no tibial force. Application of a 100-N hamstrings load significantly increased mean PCL force at flexion angles greater than 15°.

(From Markolf, K. L.; O’Neill, G.; Jackson, S. R.; McAllister, D. R.: Effects of applied quadriceps and hamstrings muscle loads on forces in the anterior and posterior cruciate ligaments. Am J Sports Med 32:1144–1149, 2004.)

FIGURE 23-6 PCL forces from 0°–120° of knee flexion under a constant 100-N posterior tibial force. Application of a 100-N hamstrings load significantly increased mean PCL force at flexion angles between 30° and 105°.

(From Markolf, K. L.; O’Neill, G.; Jackson, S. R.; McAllister, D. R.: Effects of applied quadriceps and hamstrings muscle loads on forces in the anterior and posterior cruciate ligaments. Am J Sports Med 32:1144–1149, 2004.)

Protocol for Partial or Acute Isolated PCL Ruptures

This program does not apply to PCL avulsions in which surgery may be indicated and partial tears with 5 mm or less of increased posterior tibial translation. The goal with completePCL disruptions (8–10 mm of increased posterior tibial translation at 90° flexion) is to allow PCL healing and possibly reduce some of the posterior tibial translation. Importantly, this includes maintaining normal tibiofemoral contact at full knee extension or with knee flexion. An anterior drawer produced by the therapist during motion will allow for healing of PCL fibers with the least amount of residual abnormal PCL elongation and posterior tibial translation. Although clinical data are not available, the empirical favorable experience of the authors warrants the program described below.

The rules to treat partial or acute isolated PCL tears are

FIGURE 23-7 Knee extension brace with posterior calf pad to maintain tibiofemoral reduction.

PCL Reconstruction Postoperative Protocol

Immediate Postoperative Management

Patients present to physical therapy the 1st day after surgery on bilateral axillary crutches in a postoperative dressing with a long-leg brace locked in full extension (Table 23-1). The postoperative bandage and dressing are changed to allow the application of thigh-high compression stockings and a compression bandage. Early control of postoperative effusion is essential for pain management and early quadriceps reeducation. In addition to compression, cryotherapy is important in this time period.

TABLE 23-1 Rehabilitation Protocol after Posterior Cruciate Ligament Reconstruction

Critical Points IMMEDIATE POSTOPERATIVE MANAGEMENT

Postoperative compression dressing, long-leg brace, compression stockings, cryotherapy, lower limb elevation, pain management.

Common Complications

• Excessive pain/swelling.

• Quadriceps shutdown.

• Limitation knee flexion, extension.

Early detection and treatment complications critical.

Brace Support

• PCL reconstruction

Long-leg hinged brace 8 wk.

Functional PCL brace return to higher level occupational or sports.

• PCL reconstruction with posterolateral procedure

Bivalved cast 4 postoperative wk.

Lower extremity, hinged, double-upright brace applied locked at 10° of extension 4–6 wk.

Brace unlocked 6 wk to allow flexion.

Custom medial unloading brace at 8 wk.

Range of Knee Motion

• Passive flexion, passive & active-assisted extension exercises 1st day postoperative, 0°–120°.

• Advance flexion slowly, limit total number daily knee cycles to 60 for first 4 wk.

• Flexion is passive for first 12 wk, avoid hamstring activation.

• 135° allowed 7–8 wk.

Begin ROM overpressure program 1 wk postoperative if 0° not achieved.

Weight-Bearing

• Partial weight-bearing first 6 wk, full 7–8 wk.

• Weight-bearing progressed using normal gait technique, avoid locked-knee position, encourage normal flexion throughout gait cycle.

• Warn avoid squatting, walking down hills or ramps, any sudden deceleration movements for at least 6 mo.

PCL, posterior cruciate ligament; ROM, range of motion.

Patients are instructed to keep the lower limb elevated as frequently as possible during the 1st week. The initial response to surgery and progression during the first 2 weeks sets the tone for the initial phases of the rehabilitation program. Common postoperative complications include excessive pain or swelling, quadriceps shutdown, and range of motion (ROM) limitations. Early recognition and treatment of these problems are critical for a successful outcome.

Range of Knee Motion

Passive knee motion from 0° to 120° is allowed immediately postoperatively. Although patients are encouraged to regain full extension as soon as possible, knee flexion is limited for the first 7 to 8 postoperative weeks to avoid high posterior shear forces. The total number of daily knee motion cycles is limited to 60 (20 cycles, three times/day) for the first 4 weeks to limit undue abrasion of the graft.^12,20

Regaining knee extension as soon as possible is important to avoid excessive scarring in the intercondylar notch or a posterior capsular contracture. Patients who do not achieve this extension goal by the 7th postoperative day are placed into an overpressure program. The foot and ankle are propped on a towel or other device that elevates the hamstrings and gastrocnemius, allowing the knee to drop into full extension. This exercise is performed for 10 minutes and repeated approximately six times per day. A 10-pound weight may added to the distal thigh and knee to stretch the posterior capsule (Fig. 23-8). Care should be taken to keep the hanging weight away from the proximal tibia to avoid posterior shear stresses. Zero degrees of knee extension should be obtained by the 3rd to 6th postoperative weeks. If this is not accomplished, or if the clinician notes a firm end feel, a serial casting program may be required (see Chapter 41, Prevention and Treatment of Knee Arthrofibrosis). Hyperextension is avoided to protect the healing PCL graft.

FIGURE 23-8 Extension overpressure using hanging weights.

Passive knee flexion exercises are performed in the seated position, using an anterior manual force to provide proximal tibial support to prevent posterior drop-back. A 10-pound anterior drawer is maintained on the proximal tibia during passive knee flexion (Fig. 23-9) because PCL forces significantly increase after 70° of flexion. Knee flexion exercises are primarily passive for the first 6 weeks and are then active for the next 6 weeks. Care must be taken to avoid activating the hamstrings. Other overpressure techniques to assist in gaining flexion include chair-rolling (Fig. 23-10), wall-sliding using the opposite extremity (Fig. 23-11), commercial devices (Fig. 23-12), and passive quadriceps-stretching exercises.

FIGURE 23-9 Flexion knee motion exercises using anterior tibial pressure to prevent posterior tibial drop-back.

FIGURE 23-10 A and B, Flexion overpressure using a rolling stool.

FIGURE 23-11 A and B, Flexion overpressure using a wall-slide technique.

FIGURE 23-12 A commercial knee flexion overpressure device.

Patellar Mobilization

Patellar mobilization is important in the promotion of a full range of knee motion. The loss of patellar mobility is often associated with knee motion complications and, in extreme cases, the development of patella infera.¹⁸ Patellar glides are performed in all four planes (superior, inferior, medial, and lateral) with sustained pressure applied to the appropriate patellar border for at least 10 seconds (Fig. 23-13). This exercise is performed for 5 minutes before ROM exercises are completed. Caution is warranted if an extensor lag is detected, because this may be associated with poor superior migration of the patella, indicating the need for additional emphasis on this exercise.Patellar mobilization is performed for approximately 8 weeks postoperatively.

FIGURE 23-13 Patellar mobilization.

Critical Points PATELLAR MOBILIZATION, MODALITIES, FLEXIBILITY

Patellar Mobilization Paramount to Achieving Full Knee Motion

• Superior, inferior, medial, lateral directions—5 min—when ROM exercises are performed.

• Extensor lag may be associated with poor superior patellar migration.

Modalities

• EMS if quadriceps rated fair or poor.

• Biofeedback for quadriceps activation.

• Cryotherapy, entire rehabilitation period.

Flexibility

• Hamstring, gastrocnemius-soleus begun 1st day

Modified hurdler.

Towel-pull.

• Quadriceps, iliotibial band begun 9th wk.

EMS, electrical muscle stimulation; ROM, range of motion.

Strengthening

The strengthening program is begun on the first postoperative visit. Early emphasis on the quadriceps muscle group is critical for a safe return to functional activities and to prevent posterior subluxation of the tibia from occurring during activities in which the knee is flexed greater than 50°. In this phase of rehabilitation, initiation of a good voluntary quadriceps contraction sets the tone for the progression of the strengthening program.

Isometric quadriceps contractions are done every hour following the repetition rules of 10-second holds, 10 repetitions, 10 times per day. Evaluation of the contraction by both the therapist and the patient is critical. The patient can monitor contractions by visual or manual means, comparing the quality of the contractions to those achieved by the contralateral limb. She or he can also assess the superior migration of the patella during the contraction, which should be approximately 1 cm, and the inferior migration of the patella during the initial relaxation of the contraction.

Critical Points STRENGTHENING

1–2 Wk Postoperative

• Quadriceps isometrics

• Straight leg raises (flexion)

• Active-assisted knee extension, 0°–70°

3–4 Wk Postoperative

• Multi-angle quadriceps isometrics 0°, 60°

• Straight leg raises (flexion, adduction)

• Active-assisted knee extension 0°–90°

5–6 Wk Postoperative

• Multiangle quadriceps isometrics 30°, 60°, 90°

• Straight leg raises (flexion, adduction)

• Active-assisted knee extension 0°–90°

• Heel-raise/toe-raise

• Wall-sits

• Multi-hip machine

• Leg press 50°–10°

7–8 Wk Postoperative

• Straight leg raises (flexion, adduction, abduction), rubber tubing

• Active knee extension 0°–90°

• Mini-squats 0°–30°, rubber tubing

• Wall-sits

• Multi-hip machine

• Leg press 50°–10°

9–12 Wk Postoperative

• Straight leg raises (flexion, adduction, abduction, extension), rubber tubing

• Hamstring curls 0°–90°

• Active knee extension 0°–90°

• Mini-squats 0°–40°, rubber tubing

• Wall-sits

• Lateral step-ups 2”–4” block

• Multi-hip machine

• Leg press 50°–10°

13–26 Wk Postoperative

• Hamstring curls 0°–90°

• Knee extension with resistance 30°–90°

• Mini-squats 0°–40°, rubber tubing

• Wall sits

• Lateral step-ups 2”–4” block

• Multi-hip machine

• Leg press 50°–10°

27–52 Wk Postoperative

• Hamstring curls with resistance 0°–90°

• Knee extension with resistance 30°–90°

• Multi-hip machine

• Leg press 70°–10°

Other exercises performed immediately postoperatively are supine straight leg raises and active-assisted knee extension (70°–0° postoperative wk 1 and 2, then 90°–0°). The patient must achieve a sufficient isometric quadriceps contraction with the leg raises to benefit the quadriceps. Initially, 1- to 2-pound ankle weights are used; and eventually, an ankle weight up to 10 pounds is used as long as this does not represent more than 10% of the patient’s body weight.

Active-assisted ROM facilitates the quadriceps muscle if poor tone is observed during isometric contractions. At postoperative weeks 3 to 4, adduction and abduction straight leg raises are incorporated. The exceptions are in knees that undergo concomitant posterolateral procedures, for which abduction leg raises are delayed until postoperative weeks 7 to 8. Extension leg raises are initiated at postoperative week 9. These exercises are continued through at least postoperative week 12, at which time emphasis is placed on controlling pain and swelling, regaining full ROM, achieving quadriceps control and proximal hip stabilization, and resuming a normal gait pattern.

Once partial weight-bearing is initiated, CKC exercises are begun. The first CKC exercise is cup-walking, an activity designed to facilitate adequate quadriceps control during midstance of gait to prevent knee hyperextension from occurring (Fig. 23-14). When the patient progresses to 50% to 75% weight-bearing, toe-raises for gastrocnemius-soleus strengthening, wall-sitting isometrics for quadriceps control, and mini-squats for quadriceps strengthening are begun. The goal of wall-sitting is to improve quadriceps contraction by performing the exercise to muscle exhaustion. This exercise may be modified to decrease patellar pain or place additional stress on the quadriceps muscle. Patellar pain may be decreased by either altering the knee flexion angle of the sit or subtly changing the toe-out/toe-in angle by no more than 10°.

FIGURE 23-14 A and B, Cup-walking used early postoperatively to develop symmetry between the surgical and the contralateral limbs, hip and knee flexion, quadriceps control during midstance, hip and pelvic control during midstance, and adequate gastrocnemius-soleus control during push-off.

Additional stress to the quadriceps can be accomplished by several methods. First, the patient can voluntarily set the quadriceps muscle once he or she reaches his or her maximum knee flexion angle, which is typically between 30° and 45°. This contraction and knee flexion position is held until muscle fatigue occurs, and the exercise is repeated two to three times, for eight repetitions per day. In a second modification, the patient performs a hip adduction contraction by squeezing a ball between the distal thighs. This modification promotes a stronger VMO contraction. In a third variation, the patient holds dumbbell weights in his or her hands to increase body weight, which promotes an even-stronger quadriceps contraction. Finally, the patient can shift his or her body weight over the involved side to stimulate a single-leg contraction. These exercises are highly beneficial and result in the patient experiencing a true muscle burn as each repetition is held to maximum quadriceps muscle fatigue, which is not achieved at this point with other exercises. The sets should be performed ideally twice each and repeated five to six times a day.

The last CKC exercise is the mini-squat. Initially, the patient’s body weight is used as resistance. Gradually, TheraBand or surgical tubing is employed as a resistance mechanism (Fig. 23-15). The depth of the squat is controlled to protect the patellofemoral joint. Quick, smooth, rhythmic squats are performed to a high-set/high-repetition cadence to promote muscle fatigue. Hip position is important to monitor in order to emphasize the quadriceps. Increased trunk flexion facilitates increased hamstring contractions¹⁹ and, therefore, must be carefully monitored to avoid forceful hamstring contractions for a minimum of 3 to 6 months.

FIGURE 23-15 Mini-squats made more difficult with TheraBand.

OKC exercises are included in the rehabilitation program owing to the advantage of muscle group isolation provided by weight machines. Initially, if the lightest amount of weight on the machine is too heavy to be lifted by the involved limb alone, the patient is instructed to lift the weight with both legs and lower it with the involved side. Eccentric contractions can also be used in the advanced stages of strength training if tendinitis or overuse syndromes develop. Weight training is used in the latter stages of rehabilitation and continues after the patient has returned to activity.

The timing of the initiation of extension, hip, leg press, and hamstring curl OKC exercises is shown in Table 23-1. Knee flexion hamstring curls are delayed until the 12th postoperative week to avoid excessive posterior shear forces incurred with this activity. Leg press (range, 50°–0°) and hip abduction-adduction exercises are allowed at the 4th postoperative week. Caution is warranted owing to the potential problems knee extension OKC exercises may create for the healing graft and the patellofemoral joint. Many patients have an unsatisfactory outcome based on persistent anterior or patellofemoral knee pain, which can occur owing to improper training in the terminal phase of extension (0°–30°). Therefore, recommendations for knee extension exercises include emphasis on patellofemoral protection (monitoring for changes in pain, swelling, and crepitus) and a gradual progression of weight to avoid overuse syndromes.

A full lower extremity–strengthening program is critical for long-term success of the rehabilitation program. Gastrocnemius-soleus strength is a key component for both early ambulation and running. In addition, an upper extremity and core strength program is important for safe return to work or sports. These exercises are included as part of general conditioning and general strength-training concepts are emphasized. Sports and position specificity are taken into account when devising the program to maximize its benefits.

Balance, Proprioceptive, and Perturbation Training

Balance and proprioceptive training are initiated at approximately 4 to 6 weeks postoperatively when the patient is partial weight-bearing. The first exercise involves weight-shifting from side-to-side and front-to-back. This activity assists patient confidence in the leg’s ability to withstand the pressures of weight-bearing and initiates the stimulus to knee joint position sense. A second exercise is cup-walking, which is designed to both promote strength and develop symmetry between the surgical and the uninvolved limbs. Cup-walking helps develop hip and knee flexion, quadriceps control during midstance, hip and pelvic control during midstance, and adequate gastrocnemius-soleus control during push-off and controls hip hiking.

Another helpful activity for balance control is the single-leg balance exercise. The stance position is key to making this exercise beneficial. The patient is instructed to point the foot straight ahead, flex the knee approximately 20° to 30°, extend the arms outward to horizontal, and position the torso upright with the shoulders above the hips and the hips above the ankles. The object of this activity is to stand in position until balance is disturbed. A minitrampoline or unstable surface can be used to make this exercise more challenging. The unstable position created with the soft surface requires greater dynamic limb control than that used to stand on a flat surface (Fig. 23-16).

FIGURE 23-16 Single-leg stance on an unstable platform.

Critical Points BALANCE/PROPRIOCEPTIVE/PLYOMETRIC TRAINING

Begin Balance Training 5–6 Wk Postoperative

• Side-to-side and front-to-back weight-shifting.

• Cup-walking.

• Single-leg balance.

• Styrofoam half and whole rolls.

• BAPS board, double-leg & single-leg stance.

• Balance systems.

• Computerized stability systems.

Plyometric Training

• Begin 6–9 mo postoperative, no more than 20% deficit on quadriceps and hamstrings isokinetic testing.

• Level surface box hopping on four-square grid

Double-leg hop initially, land in flexion.

Complete four levels.

Single-leg hops.

• Vertical box hopping.

Plyometric Training Considerations

• Surface: Firm but forgiving such as wooden gym floor. Avoid hard surfaces such as concrete.

• Footwear: Cross-training or running shoe. Check wear patterns, outer sole wear.

• Warm-up: Include light cardiovascular workout.

BAPS, Biomechanical Ankle Platform System.

In the early phases of full, unassisted weight-bearing, half foam rolls are used as part of the gait-retraining program. Walking on half rolls helps the patient develop balance and dynamic muscular control required to maintain an upright position and be able to walk from one end of the roll to the other. Developing a center of balance, limb symmetry, quadriceps control in midstance, and postural positioning are benefits obtained from this type of training.

Perturbation-training techniques are initiated at approximately the 7th to 8th postoperative weeks. The therapist stands behind the patient and disrupts her or his body posture and position periodically to enhance dynamic knee stability. The techniques involve either direct contact with the patient (Fig. 23-17) or disruption of the platform the patient is standing on (Fig. 23-18).

FIGURE 23-17 Perturbation technique. The therapist stands behind the patient and intermittently touches the patient’s back to disturb balance.

FIGURE 23-18 Perturbation technique. The therapist stands behind the patient and intermittently taps the unstable platform to disturb balance.

Another effective proprioceptive exercise is a balance board with the patient assuming first a double-leg stance and eventually a single-leg stance as strength and balance improve. To provide a greater functional challenge, patients may assume the single-leg stance position and throw/catch a weighted ball against an inverted minitrampoline until fatigue occurs.

The use of more sophisticated devices adds another dimension to the proprioception program, because certain units objectively attempt to document balance and dynamic control. Many balance systems are available, with a wide cost variance. Two of the more common units include Biodex’s Balance System (Biodex Medical Systems, Inc., Shirley, NY) and Neurocom’s Balance System (Neurocom, Clackamas, OR). Whereas these systems may provide objective information, more research is required to justify the cost and reliability of each unit.

Running and Agility Program

Current studies do not allow a prediction of return of strength of PCL grafts; hence, conservative estimates regarding return to strenuous activities are warranted. In order to initiate the running program, the patient must demonstrate no more than a 30% deficit in average torque for the quadriceps and hamstrings on isometric testing, have no more than 3 mm of increase in anteroposterior displacement on arthrometer testing, and be at least 6 months postoperative. The running program in an elite athlete under ideal conditions described after a quadriceps tendon–patellar bone autograft has been found in the authors’ clinic to be safe and not result in graft stretching or an increase in posterior tibial translation. However, most recreational athletes do not start the program until 9 to 12 months after surgery. The rules for when to introduce more strenuous running and cutting activities for allografts have not been scientifically established. In general, a prudent rule is to provide additional time for graft healing and remodeling and wait until 12 months, although it is recognized that allograft healing is delayed even further. The running program is designed based on the sport the patient desires to return to, as well as the particular position or physical requirements of the activity. For instance, an individual returning back to short-duration, high-intensity activities participates in a sprinting program rather than a long-distance endurance program.

The beginning level running program is first performed with a straight-ahead walk/run combination. Running distances are 20, 40, 60, and 100 yards (18, 37, 55, and 91 m) in both forward and backward directions. Initially, running speed is approximately one fourth to one half of the patient’s normal speed, and gradually progresses to three fourths and full speed. An interval training–rest approach is applied in which the rest phase is two to three times the length of the training phase. The running program is performed three times per week, on opposite days of the strength program. Because the running program may not reach aerobic levels initially, a cross-training program is used to facilitate cardiovascular fitness. The cross-training program is performed on the same day as the strength workout.

After the patient is able to run straight ahead at full speed, the program progresses to include lateral running and crossover maneuvers. Short distances, such as 20 yards (18 m), are used to work on speed and agility. Side-to-side running over cups may be used to facilitate proprioception. At this time, sports-specific equipment is introduced to enhance skill development (e.g., a soccer ball for a soccer player to work on dribbling and passing activities). These variations are useful to motivate the patient and minimize training boredom.

Critical Points RUNNING PROGRAM, RETURN TO SPORTS ACTIVITIES

Running Program

• Begin 6 mo postoperative if no more than 30% deficit on quadriceps & hamstrings peak torque on isometric testing.

• Use walk/run program initially, 3 times/wk

18, 37, 55, 91 m.

25%–50% normal running speed, straight.

Progress to 100% speed.

• Add lateral, crossover maneuvers, 18 m.

• Figure-eight running drills, 18 m initially, decrease to 9 m.

• Cutting patterns, directional change at 45° and 90°.

Return to Sports Activities

• Sports-specific drills done based on patient goals.

• No more than 10% deficit quadriceps & hamstrings peak torque on isokinetic testing.

• Successful completion running and functional training.

• Trial of function recommended, monitor for overuse symptoms.

The third level of the running program incorporates figure-eight running drills. These drills begin with long and wide movement patterns to encourage subtle cutting. The training distance initially is 20 yards (18 m); as speed and confidence improve, the distance is decreased to approximately 10 yards (9 m). Progression through this phase is similar to that used in the lateral side-to-side program just described. Speed and agility are emphasized, and as well, equipment is introduced to develop sports-specific skills.

The fourth phase in the running program introduces cutting patterns. These patterns include directional changes at 45° and 90° angles that allow the patient to progress from subtle to sharp cuts.

Plyometric Training

Plyometric training is begun upon successful completion of the running program in order to minimize bilateral alterations in neuromuscular function and proprioception. This training begins after the 9th postoperative month for patients who desire to return to strenuous athletics. Again, this training should be delayed on an empirical basis to 12 months when PCL allografts are used. The patient should demonstrate no more than a 20% deficit for the quadriceps and hamstrings on isokinetic testing. Important parameters when performing plyometric exercises are surface, footwear, and warm-up. The jump drills should be done on a firm, yet forgiving surface such as a wooden gym floor. Very hard surfaces like concrete should be avoided. A cross-training or running shoe should be worn to provide adequate shock absorption as well as adequate stability to the foot. Checking wear patterns and outer sole wear will help avoid overuse injuries.

During the jumps, the patient is instructed to keep the body weight on the balls of the feet and to jump and land with the knees flexed and a shoulder-width apart to avoid knee hyperextension and an overall valgus lower limb position (Fig. 23-19), as described in detail in Chapter 19, Decreasing the Risk of Anterior Cruciate Ligament Injuries in Female Athletes. The patient should understand that the exercises are reaction and agility drills and, although speed is emphasized, correct body posture must be maintained throughout the drills.

FIGURE 23-19 An improper, overall valgus lower limb position on landing a plyometric jumping exercise.

The first exercise is level-surface box-hopping using both legs. A four-square grid of four equally sized boxes is created with tape on the floor. The patient is instructed to first hop from. The second level incorporates both of these directions into one sequence and also includes hopping in both right and left directions.Level-three progresses to diagonal hops, and level four includes pivot hops in 90° and 180° directions. Once the patient can perform level four double-leg hops, the same exercises are done on a single leg. The next phase incorporates vertical box hops.

It is important to stress that plyometric exercise is intense and adequate rest must be included in the program. Individual sessions can be performed in a manner similar to that for interval training. Initially, the rest period lasts two to three times the length of the exercise period and is gradually decreased to one to two times the length of the exercise period. Plyometric training is performed two to three times weekly.

Improvement is measured by counting the number of hops in a defined time period. The initial exercise time period is 15 seconds. The patient is asked to complete as many hops between the squares as possible in 15 seconds. Three sets are performed for both directions and the number of hops recorded. The program is progressed as the number of hops increases, along with patient confidence.

Posterolateral Reconstruction Rehabilitation

Patients who have chronic ruptures to the posterolateral structures may develop over time an alteration in gait in which excessive knee hyperextension occurs during the stance phase, described in detail in Chapter 34, Correction of Hyperextension Gait Abnormalities: Preoperative and Postoperative Techniques. A preoperative gait-retraining program is implemented for these patients, as failure to correct this problem leads to an increased risk of failure of any posterolateral reconstructive procedure.

A variety of surgical options are available for ruptures of the posterolateral structures, which are detailed in Chapter 22, Posterolateral Ligament Injuries: Diagnosis, Operative Techniques, and Clinical Outcomes. The rehabilitation protocol incorporates immediate protected knee motion but stresses maximal protection against undue joint loads to prevent stretching and failure of posterolateral grafts or advancement procedures (Table 23-3). Patients are warned to avoid hyperextension and activities that would incur varus loading on the joint. Delays in return of full knee flexion, full weight-bearing, initiation of certain strengthening and conditioning exercises, and running and return to full sports activities are incorporated.

Posterolateral reconstructions are monitored with manual examination of lateral joint opening and external tibial rotation. Lateral stress radiographs may be used if an early increase in these knee motions is detected. Any patient who experiences difficulty progressing through the protocol or who develops a complication is expected to require additional supervision in the formal clinic setting.

The immediate postoperative management is similar to that described for PCL reconstructions. A bivalved cast is used for the first 4 postoperative weeks to provide maximum protection to the knee joint and posterolateral structures. The cast is used in this time period because many soft-hinged postoperative braces do not provide sufficient protection against excessive lateral joint opening that could occur with ambulation and produce a failure of the posterolateral reconstruction. The cast is removed four times a day for passive knee motion exercises, which are performed in a seated position with a 10-pound valgus load applied to decrease lateral joint forces. If associated with a PCL reconstruction, a combined medial-anterior load should be applied to control both varus and posterior loads. At 4 weeks postoperative, a lower extremity, hinged, double-upright brace is applied locked at 10° of flexion. The brace is removed four times daily for ROM exercises. At 6 weeks postoperative, the brace is unlocked as knee flexion to 110° is encouraged and partial weight-bearing is allowed.

It is important to recognize that, on occasion, there will be excessive soft tissue swelling or skin problems in which the bivalved cylinder cast is contraindicated. There are commercially available soft tissue hinged braces that have a design in which the hinge support and medial-lateral arms are more rigid that provide (when properly applied) a resistance to prevent abnormal lateral joint opening with ambulation. A more-flexible hinged soft tissue brace is not advised. The surgeon provides information on the expected strength of the posterolateral reconstruction. For example, a double-graft anatomic reconstruction provides considerable strength to allow a soft-hinged brace. A single femorofibular graft reconstruction has less strength, and more postoperative protection is required for the first 4 weeks.

At 7 to 8 weeks, a custom medial unloading brace is applied as weight-bearing progresses to full and flexion is advanced to 120°. The brace is also used to provide protection against knee hyperextension and excessive varus loads as patients return to activity.

Patients are allowed 0° to 90° immediately postoperatively. Flexion is slowly advanced to 110° by postoperative week 5, 120° by week 8, and 130° by week 12. Patients are cautioned to avoid varus tensioning when performing knee flexion exercises. They are taught (and the assistance of a partner is encouraged) to place a hand on the lateral aspect of the knee and create a 10-pound valgus load to protect the posterolateral structures.

Patients are not allowed to bear weight for the first 2 postoperative weeks. Then, partial weight-bearing (25% of the patient’s body weight) is begun at postoperative weeks 3 to 4, with slow advancement to full by week 8 with cane or crutch support, which is used for approximately another 3 to 4 weeks. Patients are warned to avoid knee hyperextension and activities that would incur varus loading, external tibial rotation, or lateral joint opening.

Patellar mobilization, flexibility exercises, modality usage, and the strengthening and conditioning programs are all similar to those described in the PCL reconstruction protocol.

In select athletes, a running program is begun at approximately the 9th postoperative month, and plyometric- and sports-specific–training programs are initiated at the 12th postoperative month. However, the majority of patients who require multiple ligament reconstructive procedures do not desire to return to high-impact sports, and therefore, this advanced conditioning and training is usually not required. Patients who have articular cartilage damage are advised to return to only low-impact activities to protect the knee joint.

Discharge criteria after lateral and posterolateral graft reconstructions is based on patient goals for athletics and occupations and the rating of symptoms, lateral joint opening, muscle strength testing, and function testing (Table 23-4). Lateral joint opening is assessed by either stress radiography or manual testing at 20° of flexion. The remainder of the assessment is performed as previously described for PCL reconstructions.