BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention generally relates to an apparatus for post-surgical rehabilitation of orthopedic patients who have undergone reconstruction of the rotator cuff or knee. Through use of immediate controlled post-surgical movement in the instant rehabilitative device, recovery time is significantly reduced and range of motion of an injured limb is quickly recovered.
Previously, patients were kept immobile for periods of several days to weeks following orthopedic surgery to repair the tendon or cartilage of the shoulder (rotator cuff) labrum or the knee (meniscus). The swelling or edema which resulted from the procedure made movement painful and difficult, and recovery time was extended. Recent advances in surgical procedures and materials make it possible to begin rehabilitation by moving the joint even while the patient is in the recovery room. The affected joint is anesthetized and a rotational movement is induced which substantially reduces inflammation and promotes freedom of movement. As the patient recovers, the exercise is continued, the range of movement and the load being increased steadily.
The theory is based on on a physiologic model in which a motor program activates muscles in a coordinated sequence to create joint movements that simplify and perform tasks. These programs consist of length dependent patterns which operate at one joint and result in co-contraction coupled forces and a force-dependent pattern which harmonizes motion at several joints, creating coordinated movements using agonist and antagonist force coupled activation to generate force. As applied to the shoulder, together these two patterns result in a motor program of voluntary upper extremity movements. As provided herein, the exerciser not only provides closed chain kinetic exercise which is protective to the glenohumeral joint, and also rehabilitates the scapular muscles of the shoulder.
Closed chain exercises involving axial loading from distal (hand) to proximal (shoulder joint, scapula) are a more physiologic way of stimulating normal rotator cuff function (Lephart, J., Sports Rehab 1966). Traditional isolated rotator cuff exercises (Therabands) do not integrate muscle activation, potentially creating shears across the joint and are performed in non-physiologic positions. Closed chain rehabilitation exercises can be started in early rehabilitation with the hand fixed below the shoulder level. These exercises rely on motor programs that are specific for sensory and proprioception feedback for integration and activation of the joint.
The present invention is directed to an exercise apparatus and procedure which is position specific, motion specific and functionally specific, and provides joint integration to enhance postoperative feedback, thus enhancing postsurgical rehabilitation of both the shoulder or the knee. Because the rotator cuff and the knee are systems sensitive to exercise, precise control of movement and of the variation in load are important in the rehabilitation process as is the ability to vary the range of movement through an infinitely variable system of adjustment, not limited to incremental stages. And since the therapeutic system of immediate post-surgical movement must be implemented in the recovery room, a compact device is required which will be usable while the patient is in a hospital bed. The device will also have to be used as recovery continues using a conventional table for support in the case of rotator cuff procedure and with a conventional chair for knee rehabilitation in treatment of the meniscus. Thus, an ongoing and pressing need exists for a simple, portable, robust and cost-effective device designed specifically for knee and shoulder rehabilitation.
b) Description of the Related Art
In U.S. Pat. Nos. 5,336,147 (Sweeney) and 5,161,430 (Febey) movable crank devices are disclosed for the exercise of both upper and lower body parts. Both patents disclose equipment effective for general exercise but are not practically functional for post surgical rehabilitation because of their complex, bulky construction and relatively large footprint of use (size and space required) which renders such devices unacceptable in a hospital/post surgical recovery room environment. As an example, the '147 device is directed to the treatment of hamstring muscles requiring both hand and foot pedals, the latter being disposed above the location of a bicycle seat.
Without making specific reference thereto, the literature and general commerce surrounding the present invention contains disclosures of many different embodiments of exercise equipment useful in changing the pedal radius of hand and/or foot crank pedal machines. However, in all cases such equipment is generally size and space unfriendly to surgical environments, relatively expensive, and of limited versatility. For example, one commercially available piece of equipment is comprised of a large steel body with a built-in seat, handlebars, pedal gear and mechanical resistance system, torque sensing and rate monitoring devices as well as an electronic display system to encourage the user and present performance information, all of which render it unusable in a surgical/rehabilitation setting. Free weights are also commonly used in rehabilitation, however, they are frequently dropped by patients in their compromised condition with consequent injury. Even in a controlled situation with an attendant to assist the patient and prevent such accidents, free weights do not move through a controlled path and depend upon the patient to position and move them through a prescribed and beneficial trajectory, and whose load may diminish to zero at the end of a stroke.
In accordance with the present invention, a neat, portable, compact, dual moment arm pedal support, cranking system is provided such that an unaffected (undamaged or pain free) arm or leg initially generates the power to move an affected (diminished capacity) limb through a circular stroke of smaller radius, and then by further decreasing the radius for that moment arm of the crank and/or applying greater friction to the central crank axle, subjecting the affected limb to appropriate greater stress in a successful-step healing process. In just one application the crank can be of free rotation (no friction applied to the axle) and by progressively shortening the moment arm of the pedal provided for the affected limb and lengthening that provided for the unaffected limb, the leverage provided to the affected limb is reduced, demanding that it provide more force to overcome the resistance of the system compared to the unaffected limb, whose pedal throw is longer, providing greater leverage and requiring less effort. By manipulation (or co-adjustment) of (1) the lengths of the moment arms of the crank and (2) the friction on the rotational axle of the crank (rotation resistance), harmonized motion of the effected joints can be accomplished and an injured limb can be rehabilitated back to health in a disciplined and prescribed manner.
SUMMARY OF THE INVENTION
The present invention provides a rehabilitative therapeutic exercise apparatus and process of operating same designed to satisfy the aforementioned needs of shoulder and knee surgical rehabilitation and embodies design features and process steps which avoid the shortcomings of the prior art.
Specifically disclosed herein is a rehabilitative exercise apparatus which comprises a base or pedestal having a vertically disposed shaft projecting therefrom, a telescoping extension projecting longitudinally therefrom, and a resistance adjustable bearing at the distal portion of the shaft extension. The bearing serves as a support for a crank assembly comprised of a rotatable shaft housed in the bearing and defining a horizontal axis of rotation about the supported bearing. A pair of length adjustable moment arms having pedal or limb support means extending horizontally therefrom are attached to the opposite ends of the rotatable shaft to provide means of reciprocal force leveraging about the crank shaft to effect rotation.
The vertical shaft bearing is equipped with a clamping member operated by a cam or threaded element so as to provide an infinitely adjustable range of resistance to the rotatable shaft of the crank. The moment arms are comprised of height adjustable telescopic linear assemblies each reciprocally distally attached to the rotatable beam in parallel alignment so as to form a crank about the pivot point created by the rotatable and resistance adjustable support shaft.
The height to which the vertically disposed shaft may be telescoped to and from the base is controlled by means of a hand operated threaded transverse clamp, permitting the bearing to be fixed at an infinity of locations within the range of the shaft's length. This is important therapeutically to increase the range of movement of the patient over a series of exercise sessions. The crank height will be set at a low setting initially and will be progressively raised as healing progresses.
As indicated, the rotatable horizontally disposed beam housed by the bearing supports a crank assembly which includes a pair of left and right height adjustable moment arms attached to each end of the rotatable beam and disposed vertical to the beam's horizontal axis. Additionally included in the assembly are a pair of pin elements, grips, or throws attached to each moment arm in parallel axial disposition to the rotational beam axis to provide limb supports in the form of pedals or handles at the distal end opposite the pivot fixed point of the moment arm to the beam. Each adjustable moment arm is comprised of a pair of interrelating male-female elongated members having a telescoping relationship with one another to form a telescoping assembly which can be adjusted in length to provide lesser or greater radii of action in the crank assembly. Fixation of the length of the moment arm can be accomplished by a hand-operated transverse threaded clamp, a pin mechanism or any other means which can set the height of the telescopic moment arm assembly to accommodate any user's rotation tolerance in a particular rehabilitative therapy.
In a preferred embodiment, the limb support at the distal end of each moment arm is equipped with a rotatable handle or foot pedal having a resilient grip when used by the hand and a non-slip (skid) surface when used by the foot. This rotatable support can be attached to the limb support such as a slideably attached pedal or handle to accommodate different constructions of hand or foot support elements. It is further preferred that any version of handle or pedal be equipped with a quickly-releasable strap to secure the hands or feet to the pedal or handle.
The base is fabricated of metal or other heavy material to confer balance and stability to the apparatus. As an optional embodiment, the underside of the base is provided with a plurality of fixed open suction cups to permit attachment of the apparatus to a tabletop for use in rotator cuff procedures and to the floor for use in knee procedures a further feature of the present invention is that the outer components of the height adjustable shaft and moment arms can be marked by means of engraving or other permanent technique to facilitate setting to prescribed heights and radii. In each case the height adjusting clamping or pin member is employed as the cursor or moving reference for the user.
Accordingly, it is an object of the present invention to provide a compact portable rehabilitative exercise apparatus for the rotator cuff and/or the knee which has the capability for shoulder and knee rehabilitation; which allows progressive (competitive) resistance exercising; and provides the capability of working the arm or leg at an infinite number of positions and degrees of resistance. It is a further object of the instant invention to provide a compact, portable exercise apparatus which is usable from a hospital bed with a conventional table or conventional chair; and to provide a portable piece of limb rehabilitative equipment which is competitive in cost and easily affordable. These and other objects and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.