Journal of Sport Rehabilitation, 1992, 1 , 249-257

Techniques of Manual Therapy for the Knee

William E. Prentice

Various techniques of manual therapy are available to the sports therapist supervising a rehabilitation program. Joint mobilization and proprioceptive neuromuscular facilitation (PNF) techniques can be effectively used in re- habilitation of the injured knee for achieving normal joint range of motion and for strengthening the weak components of a movement pattern. Joint mobilization is used to restore normal accessory motion to the joint. The PNF strengthening techniques are used for improving normal physiological mo- tion. These manual therapy techniques allow the sports therapist to concen- trate on the rotational component of motion at the knee joint, which is often neglected in rehabilitation programs.

In order for the sports therapist to be effective in treating many acute and chronic musculoskeletal disorders, some basic knowledge of the various techniques of manual therapy is essential. Certainly the goal of treatment is to restore normal, pain-free movement (4). Following injury to the knee joint, there will typically be some loss of motion. The skillful sports therapist can analyze existing motion to determine how specific movements relieve or exacerbate the symptoms asso- ciated with an injury. The purpose of manual therapy is to restore optimal function of a body part following injury by decreasing pain, increasing or decreasing joint mobility, and using passive and active or resistive exercise to affect movement (1).

Joint mobilization and proprioceptive neuromuscular facilitation (PNF) are two manual therapy techniques that are useful in achieving this purpose, particu- larly in the knee. The knee joint is generally considered to be a hinge joint. The implication of the term hinge joint typically means motion in only one plane. How- ever, the tibial-femoral joint is capable not only of flexion and extension but also of rotational movement. Thus the knee is not a true hinge joint. Motion is three- dimensional, occurring simultaneously in three cardinal planes. Knee motion is also dependent on the arthrokinematics of the joint, which refers to motions of the articulating joint surfaces relative to one another. Joint mobilization is used for improving joint arthrokinematics, while the PNF techniques are useful in addressing the flexion, extension, and rotational components of motion.

William E. Prentice is with the Dept. of Physical Education, Exercise and Sport Science, 214 Fetzer, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-8700.

250 Prentice

Physiological Versus Accessory Motion

Movement at the knee joint involves both physiological and accessory motion. Physiological motion is achieved when an external force moves the body part throughout the range. Such movement occurs in the cardinal movement planes and includes flexionlextension, abduction/adduction, and rotation. Accessory motion, also referred to as arthrokinematics, occurs between articulating surfaces of a joint involved in physiological motion and is described by such terms as spin- ning, gliding, or rolling. Physiological movement is voluntary while accessory movements normally accompany physiological movement. The two occur simul- taneously. Although accessory movements cannot occur independently, they may be produced by some external force. Physiological motion is certainly the most important aspect of movement. However, motion through a normal, pain-free range cannot occur without accessory movements (2, 11, 12).

Accessory motions can be classified as either spin, glide, or roll movements (10). Spin movements involve rotation about a stationary axis. Gliding occurs involuntarily when two surfaces slide with respect to one another. Also called translation, it occurs only when two surfaces are congruent and flat or congruent and curved. Rolling occurs when two joint surfaces that are not congruent move on one another. In most articulations, one articular surface is considered to be concave and the other convex. In many joints, both rolling and gliding motions occur simultaneously at some point in the range of motion (e.g., knee flexion and extension). The concave-convex rule says that if the concave surface is mov- ing on a fixed convex surface, rolling and gliding will occur in the same direc- tion. However, if the convex surface is moving on the concave surface, gliding and rolling will occur in opposite directions (19).

Physiological and accessory movement may be hypomobile, normal, or hypermobile (3). Each joint has an anatomic limit to motion that is determined both by bony arrangement and surrounding soft tissue. In a hypomobile joint, motion stops at some point referred to as a pathologic point, short of the anatomic limit, due to pain, spasm, or tissue resistance. A hypermobile joint will move beyond its anatomic limit due to laxity in the surrounding structures. A hypomo- bile joint should respond well to techniques of mobilization and manipulation. A hypermobile joint should be treated with strengthening exercises, stability exer- cises and, if indicated, taping, splinting, or bracing (15).

Sports therapists have commonly used passive physiological movement to improve range of motion. This has traditionally been accomplished by using either sustained (static) or oscillating (ballistic) stretches (16, 17). The concept of ac- cessory movement is critical in manual therapy. Generally, techniques designed to improve accessory motion can be used for tight articular structures when primary resistance is encountered from the ligaments and capsule of the joint. They can be done in any portion of the physiological range, in any direction; they cause less pain for degree of range of motion gained, and are relatively safe techniques to use (1).

Mobilization Techniques

The techniques of joint mobilization are used to improve joint mobility or to de- crease joint pain by restoring accessory movements to the joint, thus allowing for full, nonrestricted, pain-free range of motion (21). Mobilization techniques

Manual Therapy for the Knee 251

may be used to attain a variety of treatment goals including pain reduction, decreas- ing muscle guarding, and stretching or lengthening of tissue surrounding a joint, in particular capsular and ligamentous tissue-They can lead to reflexogenic ef- fects that either inhibit or facilitate muscle tone or the stretch reflex. They can have proprioceptive effects that improve postural and kinesthetic awareness (1).

Movement throughout a range of motion can be quantified with various measurement techniques. Physiological movement is measured with a goniometer and comprises the major portion of the range. Accessory motion is thought of in millimeters, although it is not measured precisely. Thus, treatment techniques designed to improve accessory movement are generally small amplitude move- ments that involve gliding or translation of one articular surface relative to the other. The amplitude is the distance that the joint is moved passively within its total range. Mobilization techniques utilize these small amplitude oscillating mo- tions within a specific part of the range. Typical treatment of a joint may involve a series of three to six mobilizations lasting up to 30 seconds, with one to three oscillations per second (1 1).

Mobilization should be done with both the athlete and the sports therapist in a comfortable position. The sports therapist should mobilize one joint at a time. The joint should be stabilized as near to one articulating surface as possible, while moving the other with a firm confident grasp.

Maitland (1 1, 12) has described the total amount of both physiological and accessory motion available in one direction and categorized mobilization tech- niques into five grades as follows:

Grade I. This is a small amplitude movement at the beginning of the range of movement, used when pain and spasm limit movement early in the range of motion.

Grade II. This is a large amplitude movement within the midrange of movement. It is used when spasm limits movement sooner with a quick oscilla- tion than with a slow one, or when slowly increasing pain restricts movement halfway into the range.

Grade III. This is a large amplitude movement up to the pathological limit in the range of movement. It is used when pain and resistance from spasm, inert tissue tension, or tissue compression limit movement near the end of the range.

Grade N. This is a small amplitude movement at the very end of the range of movement, used when resistance limits movement in the absence of pain and spasm.

Grade V. This is a small amplitude, quick thrust delivered at the end of the range of movement, usually accompanied by a popping sound called a manipu- lation. It is used when minimal resistance limits the end of the range. Manipula- tion is most effectively accomplished by the velocity of the thrust rather than by the force of the thrust. Most authorities agree that manipulation should only be used by persons trained specifically in these techniques, since a great deal of skill and judgment is necessary for safe and effective treatment (4).

In Maitland's system, Grades I and 11 are used primarily for treatment of pain while Grades 111 and IV are used for treating stiffness. It is necessary to treat pain first and stiffness second (11).

Figure 1 shows the various grades of oscillation that are used in a joint with some limitation of motion. As the severity of the movement restriction in- creases, the point of limitation (PL) will move to the left away from the anatomic

Prentice

Grade If1 I 4

Grade IV at 7 Grade II - - limit of range! - Grade V

I - *

BP (Ekgmning

Point m Range of Mollon)

PL AL (Pant of (Anatomic

L~m~talion) Llmil)

Figure 1 - Maitland's five grades of motion.

limit (AL) of motion. However, the relationship between each of the five grades in terms of their position within the range of motion remains the same.

The shape of the articulating surfaces usually dictates the direction of the mobilization being performed. When the concave surface is stationary and the convex surface is moving, mobilization or gliding should be done in the opposite direction of the bone movement. In the knee, if the tibia is fixed and the femur is the movable segment, anterior glides of the femur should be used if knee flexion is restricted. If the convex articular surface is stationary and the concave surface is moving, the mobilization or glide should be done in the same direction as the bone movement. In this case the femur is fixed and the tibia is mobile, thus an- terior glides of the tibia must be used if knee extension is restricted.

It is likely that the direction of the technique used is in whichever direction produces the primary complaint of either pain or stiffness. Usually in acute con- ditions it is the direction that reduces pain. In chronic conditions it is the direc- tion that increases mobility, thus decreasing stiffness. It should also be mentioned that if mobilization in the appropriate direction exacerbates complaints of pain or stiffness, the sports therapist should apply the technique in the opposite direc- tion until the patient can tolerate the appropriate direction (22).

Traction Techniques

Kaltenborn (6) has proposed a system incorporating traction as a means of mobiliz- ing a joint. Traction separates the joint surfaces to varying degrees into a loose packed position, thus increasing the mobility of the joint. According to Kalten- born, traction should always be used along with mobilization. Whereas Maitland has divided motions within the full range into grades, Kaltenbom has labeled these grades as stages (see Figure 2) and defined them as follows:

Stage I (Piccolo). This is traction that neutralizes pressure in the joint without actual separation of the joint surfaces. The purpose is to relieve pain by reducing the grinding of articular surfaces during mobilization. This stage is analagous to a Grade I mobilization.

Stage ZZ (Take up the Slack). This is traction that effectively separates the articulating surfaces and takes up the slack or eliminates play in the joint capsule. Stage 11 is used to relieve pain and is the same as a Grave IV mobilization.

Stage ZZZ (Stretch). This is traction that involves actual stretching of the soft tissue surrounding the joint for the purpose of increasing mobility in a hypo- mobile joint.

Manual Therapy for the Knee 253

Stage I Piccolo - I I

Stage 1 Take up slack ! _ Stage Ill Stretch * I - 1

BP (Beg~nning

Potnt in Range of Motion)

PL AL (Point of (Anatwnic

Limitation) Ltrn~t)

Figure 2 - Kaltenborn's stages of traction.

Contraindications to Mobilization

Techniques of mobilization and manipulation should not be used haphazardly. They should generally not be used in cases of inflammatory arthritis, malignancy, bone disease, neurologic involvement, bone fracture, congenital bone deformities, and vascular disorders of the vertebral artery. It should be reemphasized that manipulation should be performed only by sports therapists who are specifically trained in this procedure, since some special knowledge and judgment is required for effective treatment (22).

Proprioceptive Neuromuscular Facilitation Techniques

As indicated earlier, the literature clearly documents the importance of the rota- tional component of motion in the normal knee joint (8, 9, 13, 14). Likewise, sports medicine personnel are keenly aware of rotational instabilities that may be evident during an evaluation following acute injury. But for some reason the importance of the rotational movement of the tibia with respect to the femur is often totally neglected in rehabilitation programs.

Flexion and extension exercises have long been accepted as part of a basic standard protocol in the rehabilitation of most knee injuries. Various types of exercise equipment have been developed that facilitate strengthening in a single plane. Both isotonic and isokinetic equipment is available which can provide re- sistance in both flexion and extension movements. However, relatively little equip- ment has been designed to provide resistance in internal and external tibial rotation. Thus the sports therapist must rely primarily on manual resistance strengthening techniques to provide appropriate resistance for strengthening tibial rotation throughout the range of motion.

Perhaps the most effective manual resistance method for strengthening in- ternal and external rotation of the tibia is based on a proprioceptive neuromuscular facilitation (PNF) technique, although there is no research evidence to support this (18). PNF strengthening techniques allow the injured person to work at the maximal physical capabilities within the limitations of the injury. There is little question that continued activity during a rehabilitation program is critical for im- proving stength. Therefore an intense program of strengthening throughout a full range of motion should offer the greatest potential for recovery (20).

The PNF technique for strengthening tibial rotation incorporates strength- ening of synergistic movement patterns of the entire lower extremity. This is

important because the brain recognizes only gross joint movement and not in- dividual muscle action (20). It is also true that the strength of a muscle contrac- tion is directly proportional to the number of activated motor units. Therefore, to increase the strength of a muscle, the maximum number of motor units must be stimulated in order to facilitate the remaining muscle fibers (5, 7). This is referred to as an irradiation or overflow effect, and it occurs when the stronger muscle groups assist the weaker muscle groups in completing a particular move- ment. This cooperation leads to the rehabilitation goal of return to optimal func-

I tion (7). Since the tibia must rotate to allow normal knee flexion and extension,

I a manual resistance technique that can provide appropriate resistance to strengthen tibial rotation specifically should facilitate the rehabilitation process.

Lower Extremity Patterns

The lower extremity PNF technique for strengthening tibial rotation involves two diagonal patterns of movement, both of which require flexion, extension, abduction/adduction, and internallexternal rotation of the joints in the lower ex- tremity. These patterns are concerned with gross movement as opposed to specific muscle actions. All PNF techniques are composed of both rotational and diagonal exercise patterns which are necessary in most sport and normal daily activities (7).

The movement patterns labeled Diagonal 1 and Diagonal 2 in Tables 1 and 2 make use of a specific PNF strengthening technique known as slow-reversal.

Table 1

Diagonal 1 Movement Patterns

Moving into flexion Moving into extension Starting position Terminal position Starting position Terminal position

Hip

Knee Position of

tibia Ankle & foot

Toes Hand position*

Verbal commands

Extended Flexed Abducted Adducted Internally Externally

rotated rotated Extended Flexed Externally Internally

rotated rotated Plantar flexed Dorsiflexed Everted Inverted Flexed Extended Right hand on dorsimedial surface

of foot Left hand on anteromedial thigh

near patella Pull

Flexed Extended Adducted Abducted Externally Internally

rotated rotated Flexed Extended Internally Externally

rotated rotated Dorsiflexed Plantar flexed Inverted Everted Extended Flexed Right hand on lateralplantar surface

of foot Left hand on posteriorlateral thigh

near popliteal crease Push

*For right leg.

Manual Therapy for the Knee

Table 2

Diagonal 2 Movement Patterns

Moving into flexion Moving into extension Starting position Terminal position Starting position Terminal position

Hip

Knee Position of

tibia Ankle & foot

Toes Hand position*

Verbal commands

Extended Flexed Abducted Abducted Externally Internally

rotated rotated Extended Flexed Externally Internally

rotated rotated Plantar flexed Dorsiflexed Inverted Everted Flexed Extended Right hand on dorsilateral surface

of foot Left hand on anterolaterai thigh near

patella Pull

Flexed Extended Abducted Adducted Internally Externally

rotated rotated Flexed Extended Internally Externally

rotated rotated Dorsiflexed Plantar flexed Everted Inverted Extended Flexed Right hand on medialplantar surface

of foot Left hand on posteriormedial thigh

near popliteal crease Push

*For right leg.

This technique involves an isotonic contraction of agonistic muscle groups fol- lowed immediately by an isotonic contraction of antagonistic muscle groups, which together produce full range motion in opposite directions. Tables 1 and 2 show the starting positions and terminal positions for both.

The correct performance of these sequential movement patterns requires close cooperation between the patient and the sports therapist. Initially, a learn- ing period will be required during which the sports therapist must instruct the patient in the appropriate technique. It must be emphasized that rotation is a critical component in any movement pattern, and the patient should concentrate specifi- cally on simultaneous rotational movement of the tibia with respect to the femur in either flexion or extension from the starting position to the terminal position.

Proper positioning is essential in applying appropriate pressure and resis- tance. The sports therapist must stand close to the patient so that accommodating resistance can be applied through the range of movement in a diagonal direction. Tibial rotation is generally a relatively weak movement compared to flexion and extension. Basically the technique attempts to use the strong components of the movement pattern to facilitate the weak components.

The patient will contract isotonically against maximal resistance until fatigue is evidenced by strength decreases in the weak components of the movement pat- tern. The specific amount of resistance given should vary so as to accommodate to differences in strength of the patient throughout the range of motion, but should

I 256 Prentice

not be so great as to prevent smooth, coordinated movement. Generally the patient will become fatigued to the point of failure after 8 to 10 repetitions of each of the two diagonal patterns.

This technique begins with the Diagonal 1 movement patterns alternating flexion and extension movements, followed by the Diagonal 2 patterns, again alternating flexion and extension movements. Hand position is perhaps the most critical single element of this technique, since manual contact with appropriate pressure is essential for influencing the direction of movement and facilitating a maximum effort. Recommended hand position is indicated in Tables 1 and 2 relative to each movement p2ttern. It should be reemphasized that the purpose of this technique is to provide resistance to those muscles that collectively rotate the tibia. Thus, concentration on the tibial rotational portion of the pattern is es- sential. The sports therapist is advised to make use of whatever hand position he or she feels is most effective in resisting tibial rotation.

A specific sequence of muscle contractions occurs in any movement pat- tern that results in a coordinated movement (7). The distal movements should occur first and should be completed by no later than halfway through the pattern. Thus, foot and ankle movements should initiate the pattern and be completed be- fore the midpoint in the movement pattern is reached. This may be accomplished by combining appropriate pressure signals through the hands with verbal com- mands to facilitate correctly timed movements. The patient should be commanded to "push" or "pull" depending on the desired direction of the diagonal pattern as indicated in Tables 1 and 2. It is important to keep both manual and verbal commands short and precise, particularly in the initial learning stages of the di- agonal patterns.

Summary

Although tibial rotation is an essential component of gross motion at the knee joint, isolated tibial rotation movement without full flexion or extension of the knee joint is of little importance. These physiological motions are not possible without the necessary accessory motions that must occur between joint surfaces. The manual therapy techniques described above provide an effective means for improving the function of the knee joint throughout a movement pattern. Mobili- zation techniques should be used when accessory motions restrict joint move- ment. The PNF techniques are useful in strengthening the physiological components of knee motion while simultaneously strengthening the other com- ponents of lower extremity motion. Incorporation of these techniques into a knee rehabilitation program at the appropriate time can greatly facilitate return to full functional activity.

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Manual Therapy for the Knee 257

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