Can Elderly Patients Learn to Limit Weight-Bearing?
Can Elderly Patients Learn to Limit Weight-Bearing?
Physical therapists often see patients with orders for limited weight-bearing due to unstable hip repair, foot ulceration or early prosthetic ambulation. The fundamental concept is that a phase of limited weight-bearing maintains ambulation, but avoids excessive pressure that may be harmful.1 Usually partial weight-bearing (PWB) is 30 percent to 50 percent of body weight, and touchdown weight-bearing (TDWB) is 10 percent of body weight.
TDWB is preferred over non-weight-bearing (NWB) for post-op hip patients, because NWB may actually create greater pressures on the hip as a result of muscle forces to maintain correct positioning of the lower extremity.2 Walkers rather than crutches are the assistive device of choice for the elderly. In fact, frail elderly patients in long-term care settings usually cannot ambulate unless they are weight-bearing as tolerated (WBAT).
In order to be able to limit weight-bearing, the patient must have:
- Intact cognition;
- Trust that the therapist will guard against a fall;
- Good pain control;
- Sufficient cardiopulmonary endurance;
- Good upper body strength and balance;
- Intact sensation.
Recently the therapists at Porthaven Care Center in Portland, OR, had the privilege of working with two motivated patients who had weight-bearing restrictions. "Helen" was 72-years-old and presented with distal femur fracture with history of wrist fracture. She was NWB for six weeks, then allowed 15 to 30 pounds weight-bearing. Later this was increased to 50 pounds with orders to "increase to 100 pounds over the next four weeks." While NWB, Helen was unable to ambulate because of wrist weakness, but by the time she was allowed to bear 30 pounds, her wrist was stronger and she could begin gait training in the parallel bars.
"Katherine," an 82-year-old woman with mild dementia and a pathological hip fracture secondary to breast cancer, was restricted to only 20 pounds weight-bearing. She never did learn to pivot during transfers and would tend to take steps on her involved side when turning. Because of general weakness and a prior mastectomy, she did not have enough upper body strength to ambulate.
An ordinary bathroom scale was used to give visual feedback to both Helen and Katherine. They were assisted while standing in the parallel bars with the involved extremity on the scale and the other on a book, which matched the height of the scale (parallel bars with built-in scales would have been easier to use). Helen quickly progressed from ambulation in the bars to use of a front-wheeled walker, but no means were available to measure the amount of weight she placed on the affected side during gait. She appeared to bear most of her weight through her arms, but it was impossible to tell just how much. Katherine was unable to learn to limit weight on her fractured hip even after three days of practice on the scale.
Relatively little is known about how limited weight-bearing can be learned by elderly patients. While the use of a bathroom scale is common in the clinic, various commercial devices are available that fit into or onto a shoe and give auditory feedback when a preset weight limit is reached.3 It is doubtful whether the patient can continue to follow the weight limit when visual or auditory feedback is discontinued.3 The literature suggests that research subjects often overshoot a target weight, partly because of the time lag between auditory feedback and motor response, and the rapid rate of loading of the lower extremity.4
Developing a Treatment Plan
If the patient can't limit weight-bearing, the physician should be informed and asked whether the patient can be WBAT. If the answer is no, then the treatment program should include:
- Transfer training with instruction to facility staff;
- Positioning to prevent contractures;
- Therapeutic exercise to improve strength and relieve stiffness;
- Wheelchair seating and positioning;
- Wheelchair mobility training;
- Pain control with TENS, ice or heat applications.
Often, elderly patients will bear weight on their affected lower extremity even if they have been told not to, especially when pain is minimal or absent. Koval and Zuckerman, orthopedic surgeons who specialize in the treatment of hip fractures in the elderly, feel there is little biomechanical justification for restricted weight-bearing after femoral neck or intertrochanteric fractures. They have found that activities such as bridging to use a bedpan generate forces across the hip approaching those resulting from unsupported ambulation.
Koval and Zuckerman have also found that unrestricted weight-bearing does not increase complication rates following internal fixation or prosthetic replacement after femoral neck or intertrochanteric fracture. In the case of subtrochanteric fracture, weight-bearing may be restricted depending on the patient's age and bone quality, the fracture pattern and the type of implant used to stabilize the fracture.5
Other research has looked at weight-bearing in relation to the type of prosthesis used. Rao et al6 compared 28 patients with uncemented prostheses who were allowed WBAT to 28 patients with uncemented prostheses who were allowed 10 percent weight-bearing for six weeks. Over a two-year period, no difference between groups was found in the amount of bone growth. Further, no compromise was found with WBAT. They concluded that PWB may slow the rehab process, increase upper extremity and contralateral hip stress and increase energy expenditure with ambulation.
There are still many questions that arise concerning weight-bearing restrictions for elderly patients: What are the relative merits of devices and training methods that provide weight-bearing feedback? Would it be easier for patients to perceive forces through the upper extremities rather than the lower extremities? What types of treatment lead to the most successful outcomes when weight-bearing is limited?
Readers are invited to e-mail comments and suggestions to Emi Storey at firstname.lastname@example.org
1. Hughes, M.A., Cooperman, J., Peterson, C., & Duncan, P.W. (March 1996). Partial weight-bearing in the older person. Topics in Geriatric Rehabilitation, (11)3: 1-8.
2. Munin, M.C., Hockenberry, P.S., Flynn, P.G., & Tooplak, W. (1998). Rehabilitation. In Callaghan, J.J., Rosenberg, A.G., & Rubash, H.E. (Eds.). The Adult Hip, Vol. II. Philadelphia: Lippincott-Raven.
3. Winstein, C.J., Pohl, P.S. & Cardinale, C., et al. (September 1996). Learning a partial weight-bearing skill: Effectiveness of two forms of feedback. Physical Therapy, (76)9: 985-993.
4. Chow, D., & Cheng, C. (May/June 2000). Quantitative analysis of the effects of audio biofeedback on weight-bearing characteristics of persons with transtibial amputation during early prosthetic ambulation. Journal of Rehabilitation Research and Development, (37)3: 255-230.
5. Koval, K.J., & Zuckerman, J.D. (2000). Hip fractures: A practical guide to management. New York: Springer-Verlag Inc.
6. Rao, R.R., Sharkey, P.F., Hozack, W.J., Eng, K. & Rothman, R.H. (1998). Immediate weightbearing after uncemented total hip arthroplasty. Clin Orthop, Apr; 10(349): 156-62.
Bob Thomas is a geriatric physical therapist and currently serves as director of ancillary services for Avamere Health in Oregon and Washington. He also lectures nationally for Great Seminars on rehab solutions for the elderly in subacute and long-term care and is an adjunct professor at Pacific University. Emi Storey is employed by Rehab Specialists, Inc., and serves as physical therapist at Porthaven Care Center and Marquis Care at Piedmont in Portland, OR. She is an alumna of Stanford University.