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Team Management of Hip Revision Patients Using A Post-Op Hip Orthosis

Dulcey Lima, CO
Robert Magnus, MD
Wayne G. Paprosky, MD, FACS

ABSTRACT

Eighty patients who underwent cementless hip revision surgery were managed postoperatively with a prefabricated, adjustable range-of-motion hip-abduction orthosis. Four patients had both hips revised. The orthosis was incorporated into the patients' nursing and occupational and physical therapy during hospitalization. Patients continued to wear the orthosis whenever they were out of bed for an average of eight weeks after surgery.

The hip orthosis was used to prevent postoperative dislocation, which some reports have indicated can occur on as many as 20 percent of all revisions. Seven of the 84 hips (8.3 percent) dislocated. The average length of hospitalization was 10 days.

This article identifies patients most at risk of dislocation, discusses the orthotic management of anterior and posterior dislocation patients, and provides specific team protocol.

Introduction

Each year thousands of hip arthroplasties are performed in the United States, usually on patients with osteoarthritis and other degenerative diseases (1). Total hip arthroplasties have been performed since 1959 when Sir John Charnley first used polymethylmethacrylate for cementing the components (2). To this day, fixing components to the skeleton remains one of the most difficult surgical problems, and aseptic loosening of either the acetabular or the femoral component is the main cause of total hip implant failure (3). When aseptic loosening occurs, the patient experiences pain and instability, and revision surgery is recommended.

Studies by Mallory et al., Rao and Bronstein, and Clayton and Thirupathi cite dislocation as a complication of both primary and revision surgery at the hip (4-6). Dislocation is attributed to several variables, including soft tissue weakness secondary to the former and current surgical procedure, poor patient compliance for hip precautions, component malposition, and poor bone stock (5). The risk of dislocation after revision surgery is higher than after primary hip surgery, and this tendency to dislocate increases with each revision (7). Dislocations require immediate medical intervention, increase hospitalization costs, and cause patients pain and suffering.

Studies by Williams and others show that using a post-op hip orthosis reduces dislocations, which could occur in as many as 20 percent of revision cases (7). The study described in this article was undertaken to determine which patients are most at risk to dislocate and to determine if use of a postoperative hip orthosis reduces the number of dislocations in this population. Figure 1 shows the distribution of patient problems that necessitated hip revision surgery.

Method

The revision surgery used in this study a cementless procedure followed by specific orthotic, nursing, and physical and occupational therapy management This study followed 84 hip revision surgeries in 80 patients over 33 months. All patients have been seen For at least 12 months following surgery This study does not involve any primary patients.

Forty-nine of the hips were operated on once before; 21 of the hips were operated on twice; and 14 of the hips were operated on three, four or five times. All patients were fit with the same type of prefabricated, adjustable range-of-motion hip-abduction orthosis following surgery.a This hip orthosis is used routinely as a prophylactic device to prevent dislocation after surgery by restricting motion that could lead to dislocation, providing a favorable environment for graft incorporation, training patients in total hip precautions and reducing the tendency of stronger hip adductors to override hip abductors (see Figure 2 ).

Demographics

Study participants included 39 females and 41 males ranging in age from 31 to 84. The average age was 61.9 years. The average length of brace wear was 8.5 weeks, and the average length of hospitalization was 10 days. Follow-up ranged from 12 to 33 months.

Before revision surgery, the patient's acetabulum and femur are analyzed through roentgenographic evaluation. Acetabular classification is based on the stability of the acetabular rim and its ability to support an acetabular component.

Type 1 defects still contain cancelous bone and have minimal deformity. With rim fixation the acetabulum can support a component, and the columns will support a prosthesis.

Although Type 2 defects demonstrate more medial bone loss and cavitary defects, structural grafts are unnecessary in all but the most involved defects. These require particulate graft.

Type 3 defects show severe bone loss, component migration and a rim that will not support a component unless structural allografting is used.

In this study, the patients had seven Type 1 defects, 53 Type 2 defects and 22 Type 3 defects. The high number of Type 2 and Type 3 defects with their corresponding bone loss and instability strongly influenced the decision to orthoticly manage all patients after revision surgery (8). Every patient had an acetabular defect.

Femoral defects also can be classified into categories to assist in surgical planning for revision patients. This classification is based on the degree of bone loss in the femur and the amount of diaphyseal support provided to the implant. Type 1 defects are similar to those found in a primary total hip arthroplasty. There is minimal bone loss, and the diaphysis and metaphysis are intact. Type 2 femoral defects demonstrate no calcar, and the subtrochanteric bonee provides little or no proximal rotational stability. To prevent rotation and migration of the component, longer stems are used to provide more distal fixation. Type 3 femoral defects have extensive metaphyseal and diaphyseal bone loss, major anteroposterior bone loss and a nonintact diaphysis. Rotational stability is provided only with an extremely long stem (9). In this study there were 12 Type 1 femoral revisions, 44 Type 2s and 19 Type 3s (9) (see Figure 3 ). Not every patient had a femoral defect.

Orthotic Protocol

The orthotist measures the patient before surgery or as soon as possible postoperatively. The nurse often takes preliminary measurements. Snug measurements are taken around the waist, the widest part of the hip and of the mid-thigh on the affected side. The patient's height and weight are noted to customize the orthosis.

Based on these measurements the appropriate pelvic module and thigh cuff are chosen. The pelvic component must fit the patient properly around the waist and hips. Usually men have a four- to six-inch development between their waist and hips, and women have a eight- to 12-inch development. If the pelvic module does not properly accommodate the development, the patient may experience excessive pressure over the trochanter and gapping at the waist (not enough development) or poor purchase over the pelvis (too much development). Patients with very weak abductors also have excessive pressure over the trochanter and must be trained to position their leg in more abduction.

The patient is fit the first or second day after surgery. If the patient is able, the orthosis is applied at the side of the bed, and the patient is transferred to a chair. In other cases, the orthotist fits the patient in bed and returns when the patient is ready to ambulate so the orthosis can be assessed during standing, sitting and walking. The orthosis is worn only when the patient is out of bed. Patients are seen after discharge if an adjustment is required.

Patients responded to questionnaires asking how they put on their orthoses after leaving the hospital and whether they found the orthosis comfortable and tolerable. Patients who wore the orthosis whenever they were out of bed were determined to be in compliance. The overall orthotic compliance rate was 90 percent. Twenty-six percent felt the orthosis was comfortable, 64 percent felt the orthosis was tolerable, and 10 percent found the orthosis intolerable. Patients who dislocated and were not compliant with orthosis wear were included in the intolerable category. All patients were initially managed to prevent posterior dislocation, which is the most common dislocation (see Figure 4 ).

During the study it became evident the orthosis was adequately protecting the patients from posterior dislocation, but occasionally a patient dislocated in bed. Fluoroscopy during the closed reduction of these patients revealed some were at risk to dislocate anteriorly. The patients with anterior dislocations all had Type 3 acetabular defects and structural grafting.

Anterior dislocations require different orthotic protocol and management; extension and external rotation are the important motions to block. The extension can be blocked by allowing a hip flexion range of 40 to 70 degrees. To control rotation a KAFO is added to the pelvic section. This provides a longer lever arm to block the external rotation. Extending the orthosis to the foot allows sagittal plane motions of flexion and extension while controlling undesirable adduction in the coronal plane and internal and external rotation in the transverse plane. The patient wears the hip-knee-ankle-foot orthosis at all times. Figure 5 describes the protocol used. Anterior dislocation should be suspected when the patient has had an acetabular reconstruction or when a patient dislocates in bed or while standing and reaching up over the head or back (see Figure 6 ).

Nursing Protocol

Nursing plays a primary role in the care of hip revision surgery patients. All patients are placed in balanced suspension traction until the middle of the third post-op day, and nurses monitor the patient's comfort and position. Nurses also care for wounds, change dressings and teach the patient proper bed mobility that is reinforced by other team members.

Patients were instructed to get out of bed toward the affected side to prevent adduction of that leg. The patient could sleep only on the affected side for the same reason. This protocol may be different than that used by other physicians. Nurses reinforced all hip precautions and transfer techniques. The hip orthosis was applied while sitting at the side of the bed whenever the patient wished to get up. Nurses also monitored patient pain, fatigue, etc., and leg position (see Figure 7 ).

Physical Therapy Protocol

Physical therapists are usually the first team member to help the patient out of traction and sit up on the side of the bed on the first postoperative day. Often they are also the first to apply the hip orthosis and move the patient to a chair.

Therapists teach patients bed mobility, hip precautions and isometric exercises. Therapists also help patients increase strength and endurance by having patients walk to the physical therapy department while using appropriate ambulation aids-often a walker or crutches. Patients are usually on one-third weightbearing status - able to place enough weight on the operative side to advance the sound leg - and progress to weightbearing as tolerated. Most patients continue receiving physical therapy - usually in their homes - for eight weeks after discharge (see Figure 8 ).

Occupational Therapy Protocol

Like all other team members, occupational therapists reinforce hip precautions and bed mobility. Therapists teach patients how to apply the hip abduction orthosis and manage clothing that is applied over the orthosis. Occupational therapists also teach patients how to manage sponge baths and toilet transfers. Showers are allowed after the staples are removed, but baths are not permitted.

The occupational therapy staff provides and teaches patients how to use adaptive equipment such as long-handled shoe horns, a leg lifter, raised toilet seat and elastic laces. Compression hosiery is not worn after the patient leaves the hospital because application requires too much forward flexion (see Figure 9 ).

Results

Eighty-four hip revision procedures were performed and treated prophylactically with the adjustable range-of-motion hip-abduction orthosis. Of these, three patients dislocated in an anterior direction (3.5 percent). The three patients' hips were repositioned with closed reduction and controlled after restraining extension and external rotation with a hip-knee-ankle-foot orthosis worn at all times.

Two of these patients were casted into a modified hip spica using the hip-knee-ankle-foot orthosis as a base. The patients wore the orthosis for three months, and neither patient dislocated again after orthosis wear was completed.

Casting tape was used only on patients who dislocated while wearing the orthosis and on those who were suspected of being noncompliant. No patient casted into his or her hip-knee-ankle-foot orthosis dislocated.

Four patients (4.8 percent) dislocated in a posterior direction. Two of these patients discontinued the brace against medical advice and dislocated at four and five weeks. They both had a closed reduction and wore the orthosis 12 more weeks with no recurrence of dislocation. The third patient fell and dislocated his hip after completing orthotic management. He had a closed reduction and remained dislocation-free after 12 more weeks of wearing the hip orthosis. The last patient dislocated the 14th week after orthotic management concluded. This patient had a closed reduction and wore the orthosis 12 more weeks without dislocation. All patients who dislocated were treated with closed reduction and did not require additional surgery.

The records of the seven patients who dislocated were analyzed to determine what characteristics might have predisposed dislocation. Several high risk factors have been identified and are listed in Figure 10 .

Discussion

After studying 84 hip revision treatments, the following protocol is recommended. First, the team approach should be employed because it provides consistent patient training. Many patients in this study were in their 70s, and a few were in their 80s. Patients in this age group often have physical and cognitive deficits preventing them from learning easily.

When all staff use the hip orthosis during the patient's hospital stay, there is a greater chance for patient compliance at home. This was verified by the 90 percent compliance rate. No data exist to prove the compliance rate is higher than it would be without the team approach, but experience using the hip orthosis without the team benefits has been less successful.

Second, the orthosis should be used on all revision patients to lessen the chance of dislocation, allow soft tissue to tighten and create the optimal environment for bone graft incorporation. If a decision is made not to use the orthosis on all revision patients, the orthosis should at least be used on patients most at risk to dislocate.

Third, patients at risk for anterior dislocation should be identified during surgery if possible so that they can be managed immediately to block external rotation and extension with a hip-knee-ankle-foot orthosis. Other high-risk patients should wear the orthosis for four to six months rather than the customary eight-week period.

Conclusion

Use of an adjustable range-of-motion hip-abduction orthosis has proven a useful adjunct to the team management of hip revision patients. This is evidenced by the orthosis wear dislocation rate of 8.3 percent as compared to the data of Williams and Mallory, which was 20 percent without orthotic management (5).

It is well documented that prolonged bed rest has detrimental effects on the elderly. With the orthosis in place, patients are now mobilized within one day of major surgery. The team can work with the patient to increase endurance, teach safety precautions and begin activities of daily living within the precautionary range-of-motion provided by the orthosis. With third-party payers demanding shorter hospital stays for joint revision patients, the hip orthosis provides a cost-effective method of promoting earlier ambulation when administered with a team approach to treatment.


Dulcey Lima, CO, is an orthotist and office manager for Oakbrook Orthopedic Services in Aurora, Ill.

Dr. Robert Magnus practices in Davenport, Iowa.

Dr. Wayne G. Paprosky, FACS, is a clinical professor at Loyola University Medical Center in Maywood, Ill., and specializes in total joint replacements.

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