TIS                         
Chapter 5
Total Joint Replacement


Management of Orthopedic Problems

TOTAL JOINT REPLACEMENTS


Joints that can be replaced: orthopedic physicians can replace virtually any peripheral joint, including the hip, knee, shoulder, elbow, wrist, metacarpal-phalangeal joints, and the ankle.

The goal of arthroplastic surgery is to improve the person's function, achieved by decreasing the pain and biomechanical deficiencies associated with the person's problem.

The goal of rehabilitation is to improve the person's function in their various occupational roles, as dictated by the persons's desired outcome.

Treatment strategies:

The Therapist's Responsibilities: PROSTHESES: Composition: metallic and polyethylene (National Institutes of Health, 1994).

Constraint: the degree of physical connection between the components of a prosthesis. Prosthetic joints have a very limited ability to resist rotary and shear forces. The capsule and ligaments of the joint provide the greatest resistance to these forces (Coomey, 1993). The components of the prosthesis accommodate axial loads much more effectively. With advances in prosthetic designs, there are fewer indications for constrained devices. However, surgeons still use them in some cases, such as with total shoulder arthroplasties when the rotator cuff muscles are of insufficient strength to support the joint. Many orthopedic surgeons tend to prefer constrained elbow prostheses as well.

Design: the goal of a well-designed prosthesis is reproduction of the anatomy with greater conformity of the surfaces, resulting in decreased wear on the prosthesis. Routinely, one can make the assumption that the greater the stability of a prosthesis, the less the available range of motion.

Fixation: General indications for TJA: General contraindications: General restrictions :

The replaced joints have lost the ability to absorb shock, therefore it is important to avoid impact loading: therefore no running or jumping for weightbearing prostheses, and no heavy lifting.

General exercises :

For the involved joint the exercise should take into consideration the sacrificed or incised structures. If lower extremity joints are replaced, therapists should strengthen the unoperated extremity. Critically evaluate what interventions work best, and reevaluate routinely for other more optimum exercises. Treatment may begin with isometrics, progressing to active or active-assisted range of motion very quickly, ending with the patient performing functional activities. Therapists will want to be very cautions in performing resisted ROM. Be sure to write the program down, and perform with the person. Respiratory exercises should be a part of any exercise program (Lewis & Bottomley, 1994, p.329).

SPECIFIC JOINT SURGERIES

The therapist's responsibilities: Apply this knowledge to the rehabilitation and education of the patient.

TOTAL HIP ARTHROPLASTY (THA):

Specific Indications include avascular necrosis of the femoral head, and fractures or non-union fractures of the hip.

Surgical approaches :

Posterolateral: Anterolateral Transtrochanteric: Rehabilitation :

equipment: abductor wedge, athrombic pumps, poss. I.V. antibiotics.

Progression varies from case to case, but routinely the person is sat at the side of bed on the first post operative day, possibly progressed to standing and short-distance ambulation on that same day.

Educate the patient in contraindicated movements, and initiate an exercise program. Antigravity SLR's are difficult for the person, and place considerable forces at the femur. Decrease these by using gravity neutral positions. Make plans for discharge from day one, and pay specific attention to the person's home environment.

Considerations: once ambulatory, avoid internal L/E rotation with the person should recline when sitting.

Avoid low surfaces that cause greater than 80 degrees of hip flexion: use elevated commode seat. Also, avoid extremely soft cushions, which would facilitate int. rotation. Alter or adapt the patient's dressing technique, practice ADL's, while observing precautions.

Signs of prosthesis failure :

Pain with movement, usually at the anterior groin and medial thigh;

Frequently an audible pop can be heard with dislocation, patient knows "something isn't right"; Abnormal positioning/shortening of limb;

Inability to weightbear (Pellegrini & McCollister, 1990, p.2752).

TOTAL KNEE ARTHROPLASTY (TKA)

Specific indications: Correction of knee deformities or instability that interfere with ADL's.

Surgical approach:

In most surgeries, physicians excise the anterior cruciate ligament (ACL), and in about half of the surgeries they remove the posterior cruciate ligament (PCL) as well. If the ACL or PCL are sacrificed, the prosthesis must make up for the loss of ligamentous stability, usually via pegs in the prosthesis (Sledge, 1990, pp3611-3612).

The PCL is more important functionally than the ACL in that it checks backward movement of the tibia on the femur, and functionally sustains greater forces, such as with stair climbing and with stand to sit transfers (Sledge, 1990).

The surgeon will take an anterior surgical approach, excising the ACL, giving easy access to the joint interior. The surgeon performs an almost complete osteotomy of the tibial plateau with the exception of a small square of the posterior intercondylar eminence. The surgeon assesses ligament balance, makes any corrections, then performs a femoral osteotomy, then patellar resurfacing, if indicated. Successful surgeries retain the biomechanics of the joint as much as possible, including a knee Q-angle of 7 - 10 degrees (Sledge, 1990).

Contraindicated Movements :

None. Be cognizant of weightbearing status, and any additional corrective surgery that the orthopod may have performed.

Rehabilitation :

Equipment: CPM - Continuous Passive Motion, Athrombic Pumps, Cryo-sleeve, possible I.V. antibiotics.

CPM efficacy is debatable: some studies show that use of the CPM doesn't increase ROM or decrease edema in individuals who are performing an active exercise program routinely. However, the machine will definitely have an impact on people who have difficulty performing exercises on their own volition. Also, the machine can at times better work within the person's pain tolerance, by spreading out the increases in PROM over a greater period of time (Malone, 1993).

Day one post-op, the person is sits at the side of the bed, then progresses to standing, transferring to chairs, and short ambulation at the therapist's discretion. Therapists should initiate an exercise program on day one, with treatment strategies emphasizing function as it relates to the person's occupational roles.

Usually the last 5 degrees of extension, and from 90 to 100 degrees are the toughest to obtain. Physicians usually want 0 to 90 degrees ROM before discharge.

Tips for acquiring full extension: place the person's heel on a pillow, with a cold pack on the knee. This applies as a force couple, slowly moving the knee into extension. Therapists can combine this with quad-sets as well.

Tips for increasing flexion: work on closed chain flexion, such as stand to sit transfers. With the person sitting in a chair, use tape markers on the floor, and give the person a goal to actively bend the knee backward to the tape marker before going back to bed. Signs of prosthesis failure:

Less incidence than for THA's. Very difficult for joint to dislocate, but loosening may occur. The person will have pain more with weightbearing than movement. Pain may refer along the bone of the defective component.

TOTAL SHOULDER ARTHROPLASTY (TSA)

Specific indications: Surgeons will use an unconstrained prosthesis if the rotator cuff musculature is intact. The rotator cuff and the labral capsular ligamentous complex maintain joint stability (Rockwood, 1990).

They will use a constrained prosthesis for torn or paralysed rotator cuff. In this case, the prosthesis must provide the fulcrum for humeral movement, increasing the potential for fracture at the insertion of the prosthesis, as well as dislocation of the joint (Rockwood, 1990).

Surgical approach :

The surgeon uses an extended deltopectoral incision from the outer one-third of the clavicle across the coracoid, extending distally across the coracoid and curving laterally along the pectorals and the anterior border of the deltoid. The subscapularis is detached from its insertion at the lesser tubercle, occasionally the pectoralis major is detached as well. The joint capsule is incised anteriorly, and the humeral head is dislocated anteriorly via external rotation and extension, and is removed via osteotomy just above the tubercles, to preserve the insertion of the rotator cuff (Rockwood, 1990).

Contraindicated movements :

Combination of abduction and external rotation, or extension and external rotation. Avoid inferior glide of the humeral head. The person should avoid rolling onto operated side, and should not use operated extremity to move self.

Rehabilitation

Equipment: possible CPM, sling and swath.

Progression varies from physician to physician. Routinely, the person wears the sling for the first week, removing it for therapies and hygiene. On post-op day one, the patient performs active elbow, wrist, and hand range of motion with the therapist. On Day 2, the therapist initiates pendulum exercises, with the patient performing these 4 - 6 times a day. Day 2 - 3 begins supine active shoulder flexion and rotation, gentle ADL's such as eating, brushing teeth, and writing. (NOT hair combing). At one week, the patient can remove the sling during the day, except when the person is out of his/her home. The therapist initiates isometrics at this time. The patient can begin RROM at 6 weeks, plus resume hair washing and combing. The patient can discontinue the sling and swath fully at or before this time. The patient usually achieves full function with the exception of lifting greater than 20 pounds by 6 months (Gristina, Roman, Kammire, & Webb, 1990).

Considerations: the person should have approximately two-thirds normal range of motion after 6 months. (30 - 40 degrees of external rotation, 95-100 degrees flexion, 100 - 110 degrees abduction).

Signs of prosthesis failure: TOTAL ELBOW ARTHROPLASTY

Majority of people have Rheumatoid Arthritis (RA);

Primary goal is relief of pain. Restoration of motion is rarely an indication for surgery.

Surgery :

Varying approaches. One of the collateral ligaments must be released to dislocate the joint; the surgeon inserts the prostheses into the capitellum and trochlear notch of the humerus and the proximal ulna . Prostheses are cemented or press-fitted. The prosthetic components must restore the center of rotation of the joint, which is located at the center of the trochlea and capitellum, and approx. 30 degrees anterior to the axis of the humerus. The normal carrying angle of 5 - 7 degrees valgus is obtained as much as possible. Rarely do surgeons replace the radial head (Sledge, 1990, p.62).

Surgeons use unconstrained and constrained prostheses equally:

Unconstrained prostheses have a higher dislocation rate.

Constrained prostheses have a higher ultimate loosening rate.

Post-op management:

The surgeon applies a posterior leaf splint in 70-80 degrees flexion and neutral forearm rotation. Therapists remove the splint 5-7 days post-op and begin gentle active and passive ROM. The patient will wear the splint between therapy sessions.

3 weeks post-op, AROM continues and the therapist begins general soft tissue stretching.

8 weeks post-op, the therapist discontinues the splint unless major ligamentous instability is present. The physician or therapist usually impose lifting restrictions on the patient.

Complications: TOTAL WRIST ARTHROPLASTY

Most orthopedic physicians prefer fusion of the joint over arthroplasty. Most patients prefer ROM over fusion, obviously. The deciding factor is the patient's persistence and range of motion requirements of occupational roles.

The most commonly used prosthesis is semiconstrained;

Allows 90 degrees palmar flexion - extension;

Allows 50 degrees radioulnar deviation;

Does not allow rotational movement (Volz, 1984).

Surgical procedure:

The surgeon excises the distal end of the radius to the level of Lister's tubercle and resects the head of the capitate distally. The surgeon then cements or press-fits the prosthesis into the distal radius, and through the capitate and the third metacarpal. Centering is critical. The axis of motion at the wrist is at the proximal pole of the capitate and vertically in line with the long axis of the third metacarpal. The surgeon aligns the proximal component is along the ulnar border of the distal radius, and the distal component in the third metacarpal.

The primary difficulty with surgery is post-operative balancing of the soft tissues and musculotendinous forces crossing the joint between the wrist flexors and the extensors (Volz, 1984).

Rehabilitation:

The wrist is splinted for 7-10 days, then the therapist begins Active and passive ROM with the patient. The splint is continued if the therapist notes muscle imbalances. The therapist may use a dynamic splint to correct these imbalances.

METACARPAL-PHALANGEAL ARTHROPLASTY

The prosthesis is a "finger joint silicone elastomer intramedullary stemmed implant." Implants are rarely cemented.

Surgical procedure:

The surgeon resects the metacarpal heads perpendicular to the shaft, preserving the collateral ligaments. The surgeon then corrects tendon imbalances and joint deformities (Swanson, et al., 1990).

The most frequent complication is post-operative instability. This is easily avoided via surgically correcting deformities and ligamentous laxity during the implant procedure.

Rehabilitation:

The patient is in a bulky post-op dressing, with hand elevated for 3-5 days. At 3 - 5 days, the therapist begins guided active and passive motions with the patient, usually via an adjustable dynamic splint, (which guides the motions in the desired planes of movement: flex-ext, and ab-adduction).

The goal of therapy is to acquire a balance between good healing of the scar tissue, and an application of tension to the scar to get the desired ROM.

At 5-7 days, the patient begins active range of motion with joint blocking, performing motions in isolated planes. With the removal of the sutures, the therapist can begin friction massage.

The therapist should keep an eye on all joints and their ranges of motion. The person may substitute one joint for another, more painful one. The patient will routinely substitute PIP motin for MP motion. The ideal ROM for a replaced joint is 0-70 degrees flexion.

COMPLICATIONS OF TOTAL JOINT REPLACEMENTS:

Remember, a prosthetic joint is never as good as the one it has replaced.

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