1. What is a hip arthroplasty?
   A hip arthroplasty is a replacement of damaged or arthritic surfaces of the hip joint with materials to    restore the integrity of the joint. Most often materials are made of metals and plastics.

   2. How do total arthroplasty and hemiarthroplasty differ?
   A total hip replacement resurfaces both the femoral    head and acetabulum. A hemiarthroplasty only    resurfaces the femoral head. It is often used for    displaced femoral neck fractures.

   3. What are the indications for these procedures?
   The main indications are to relieve pain caused by    arthritis, correct deformity, and restore range of motion    (ROM) and function. More specifically, candidates for hip    replacements have severe degenerative changes on    their hip x-rays and the failure of nonoperative    treatment to relieve their pain. Nonoperative methods    include anti-inflammatory medications, the use of a    cane, These methods should be used for 3-6 months before considering a hip arthroplasty.    Occasionally, after certain types of hip fractures, the procedure of choice may be hip replacement.    This option is chosen when the fracture cannot be repaired or repair has little chance for clinical    success, such as in an 80-year-old with a severely displaced femoral neck fracture.

4. What are the causes of osteoarthritis in the hip that progresses to a total hip replacement?
Idiopathic primary osteoarthritis (approximately 70%) ,Slipped capital femoral epiphysis, History of   trauma leading to joint incongruity, Rheumatoid arthritis, Developmental dysplasia of the hip, Avascular necrosis, Other inflammatory arthritides There is no proof that other factors such as obesity, occupational hazards, or a long history of jogging are risk factors for to a hip replacement.

5. How many hip arthroplasty procedures are performed in the United States annually?
Approximately 150,000

6. How successful are these operations?
At 1 year, approximately 95% of patients can expect a good to excellent clinical result, with minimal to no pain, the ability to walk >1 mile, increased ROM, as well as patient satisfaction with the procedure.   These results are generally maintained at 6 to 10 years after the procedure. There is about a 1% failure rate per year, yielding about a 90% success rate at 10 years.

7. Can patients develop allergies to the materials used to construct hip replacement components?
Allergic reactions to these metal and plastic components are essentially nonexistent.

8. How are the components fixed to bone?
The components can be cemented with polymethylmethacrylate or affixed with noncemented methods such as press-fit and biological ingrowth prostheses. For   a press-fit prosthesis, the component is placed in direct contact with bone, and the bone is finely machined to ensure an exact fit. In biologic ingrowth prostheses, components have a porous or meshed surface that allows bone to grow into the interstices, achieving true biologic

9. Does the mode of fixation affect rehabilitation?
Most patients after hip surgery are kept on partial weight-bearing for 6 weeks. In theory, patients with cemented prostheses are capable of bearing full weight immediately after surgery. The cement has reached 90% of its strength some 10-15 minutes mixing. Patients who have a porous ingrowth  prosthesis should be on protected weight-bearing for up to 12 weeks, as this allows time for the bone to grow into the pores of the component.

10. Should the physiatrist be aware of the surgical approach used in a hip arthroplasty?
Yes and Yes. The lateral approach involves splitting the abductors with repair back to the greater trochanter or trochanteric osteotomy with repair of the osteotomy. In either case, the repair needs 6-8    weeks to heal. The abductors (gluteus medius and minimis) are most commonly weakened and   should be a target of strengthening. The posterior approach involves splitting the gluteus maximus and releasing the short external rotators which are repaired. The hip extenders and the short external rotators are affected and should be targeted. Concentric strengthening can be started earlier. The rehabilitation specialist should be wary of the higher incidence of posterior dislocation with this approach. In addition, the hip flexors, quadriceps, and hamstrings should all be strengthened after hip replacement. The Anterior Approach for total hip replacement is a tissue-sparing alternative to traditional hip replacement surgerty that provides the potential for less pain, faster recovery and  improved mobility because the muscle tissues are spared during the surgical procedure. The    technique allows the surgeon to work between your muscles and tissues without detaching them from either the hip or thighbones-sparing the tissue from trauma. Keeping the muscles intact may also help to prevent dislocations. Witht he Anterior Approach, the surgeon uses one small incision on the     front (anterior) of yoru hip as opposed to the side or back. Since the incision is in front, you'll avoid the pain of sitting on the incision site.

11. How long will patients have significant pain after hip surgery?
  Most patients recognize within 1-2 days after surgery that their pain  is markedly different than preoperatively. The arthritis pain is typically eliminated immediately. The surgical pain can last for 2-3  weeks but progressively gets better after the first 1-2 days.   Persistent pain, especially after activities and ambulation, can persist for several months or more depending on various factors, such as the preoperative deformity or degree of muscle atrophy. It may take many months to rebuild the required muscle mass and strength to reduce this activity-related pain.

12. Can patients return to playing sports after hip replacement surgery?
Most patients can return to playing low-impact sports, such as golf, doubles tennis, and bowling, walking, and using such exercise   machines such as stationary cycles and cross-country ski simulators. High impact exercises such as running, singles tennis, basketball, volleyball, and football should be avoided, as this may lead to excessive wear of the prosthesis (unless you are Bo Jackson).

13. How long will a total hip last?
Although this will vary from patient to patient, many large series show continued good to excellent results of >90% of patients at 10 years. Hopefully future hip replacements will last even longer.

14. What is the most common cause for failure in a patient with total hip arthroplasty?
Loosening. The young, very active, and obese people are at high risk. Evidence of loosening can be detected radiographically in 5-30% of cases at 10 years.

15. When will the patient receive full benefit after hip arthroplasty?
Typically, by 3 months, the patients have regained most of their strength across the joint as well as ROM. They continue to improve throughout the first year after surgery. Usually, by 1 year, the patient has achieved full benefit from the operation.

16. Describe a general management approach in a patient with total hip arthroplasty.
Day of surgery      

• Deep breathing exercises, incentive spirometry 
• Active ankle ROM exercises

Postop day 1

• Quadriceps isometric exercises
• Gluteus muscle isometrics depending on surgical approach
• Maintain hips in abduction
• Active assisted and knee flexion exercises as tolerated

Postop day 2-6    

• Begin ambulation with a walker or crutches; initiate progressive gait training
• Cemented total hip replacement
• Weight-bearing as tolerated
• Bony ingrowth total hip replacement
• Toe-touch weight-bearing for 6 wks.
• Then advance to weight-bearing as tolerated
• Trochanteric osteotomy
• If secure reattachment, start weight-bearing as tolerated; if tenuous, partial weight-bearing  Instruct hip precautions
• Instruct energy conservation and work simplification techniques
• Active assisted exercise, progress to active ROM motion and strengthening exercises
• Teach adaptive ADLs without violating hip precautions

Postop day 7-3 mos  

• Progressive strengthening and ranging of the trunk, hip, and knee
• Closed kinetic chain exercises
• Improving endurance and gait pattern
• Eliminating the use of assistive devices
• Pool therapy, bicycling, long-distance walking, progressive stair climbing, and isotonic exercises with weights are encouraged

Postop 3 mos

• Follow-up visit
• Focus on level and location of pain, daily walking distance, sitting or standing duration, use of assistive devices, method of stair climbing, use of analgesics, and community reintegration

17. How long should a patient maintain total hip precaution?
For 12 weeks after the procedure. This allows for a pseudocapsule to reform. The incidence of dislocation is reduced by > 95% after 12 weeks.

18. How should a patient ambulate stairs after hip surgery?
"Up with the good and down with the bad." When going up stairs, the patient  leads with the nonoperative extremity and then follows with the crutches and operative extremity, taking one step at a time. When descending, the patient leads with crutches and the operative extremity and  then follows with the nonoperative extremity.

19. What are the most common cause of falls after hip surgery?
  Most falls are caused by decreased visual acuity and a decrease in balance sensation that occurs in the elderly population. With this in mind, accident prevention tips should be stressed while the patient is on a rehabilitation service, and in-home visit for safety should be considered. Fall prevention should  include measures such as ensuring that are well lit in the patient’s home; avoiding throw rugs on   floors; and avoiding thick carpets, which may cause stumbling Finally, the patient should have a  well  lit and easy path from the bed to the bathroom, as many falls occur when patients get up at night to visit the bathroom.

20. Do patients need prophylaxis for deep venous thrombosis after hip replacement?
The incidence of deep venous thrombosis measured by Doppler studies or venograms after hip surgery is > 50% in most reported series. It is therefore considered the standard of care to give some form of prophylaxis for deep venous thrombosis after hip surgery. This prophylaxis can include mechanical adjuncts, such as support hose and pneumatic compression devices, which should be continued throughout the course of the hospitalization. In addition, many surgeons give some form of pharmacologic prophylaxis, such as warfarin.

21. Define weight-bearing.
 Body weight supported through the affected limb is measured by placing the limb on a weight scale and applying force on the scale.
None                                                0% of body weight
Toe-touching weight-bearing             Up to 20% of body weight
Partial weight-bearing                       20-50% of body weight
Weight-bearing as tolerated             50-100% of body weight
Full weight-bearing                           100% of body weight

22. When can patients bear full weight after hip surgery?
Patients are typically kept on partial weight-bearing for 6-12 weeks. Most patients will walk with crutches or a walker with foot-flat weight-bearing on the operative side for the first 6 weeks. Foot-flat weight-bearing allows 50-60 lbs to be placed across the hip joint during this time. Patients are rapidly   progressed from a walker or crutch ambulation to cane ambulation for an additional 4-6 weeks and then to weight-bearing without an ambulatory assistive device usually after 3 months.
This period of partial weight-bearing is necessary to accomplish three goals:

1. It allows the soft tissues to heal adequately.
2. It allows for the muscles to reattach firmly to bone or for the trochanteric osteotomy to heal.
3. It allows more adequate time for bone ingrowth to be achieved if the patient received bone-ingrowth prosthesis.

23. What are the dangerous positions to move the hip after hip arthroplasty?
There are four basic positions to be avoided after hip arthroplasty, particularly for the first 3 months.

1. No flexion of the hip past 90° with respect to the axis of the body
2. No adduction of the leg past the midline of the body
3. No combined extension of the hip joint with external rotation of the lower extremity
4. No flexion with internal rotation

24. Why should abduction pillows be utilized? For how long?
 Use of the abduction pillow prevents the patient from getting into positions that could cause dislocation of the hip prosthesis (adduction, internal rotation). The pillows should be used after all total hip arthroplasties while the patient is sleeping or resting in bed.
Abduction pillows are typically worn for 6-12 weeks. At the end of that time, a pseudo-capsule has formed around the hip joint, and the musculature is usually sufficiently strengthened to allow proprioceptive control and stability of the joint itself. Patients who have had previous hip surgery are at higher risk for dislocation and frequently require abduction bracing.

25. What ranges of motion of the hip are allowed after hip arthroplasty?
Typically patients are allowed to flex the leg to 80 - 90° and to extend it fully. They are allowed gentle   (20 – 30°) internal and external rotation of the lower extremity. They are also allowed passive abduction as tolerated. Active abduction should be avoided for the first 6 weeks in patients who have undergone a lateral approach.

26. What is are the sequence of ambulatory aids usually given to patients after total hip replacement?
For the first day or two, the patient usually works in physical therapy on the parallel bars. He or she is then progressed to crutches or a walker for the first 6 weeks. The patient is then advanced to one crutch or cane, which is continued for an additional 6 weeks. Greater than 70% of patients are ambulatory without an assistive device at the end of 3 months.

27. Give four goals of occupational therapy after total hip replacement?

1. To reestablish basic activities of daily living (ADL) with modifications that keep the patient's ROM within restricted limits
2. To teach joint protection
3. To review fall risks
4. To provide equipment with training.

28. What special devices are used to achieve modified independence in ADL?
Elevated toilet seats, shower seats, shoe horns, elastic shoe laces, reachers that allow socks to be pulled on, and other devices.

29. Are resisted concentric exercises important after hip or knee surgery?
  Concentric exercises against resistance should be avoided for the first 6-8 weeks. During that time, the patient can perform isometrics and active ROM exercises against gravity. After the first 6-8 weeks, resisted open kinetic chain strengthening can start in the place of joint motion with 1-10 lbs. Exercises performed with heavy weights against resistance cause undue wear on the prosthetic components.

30. What about sex after joint replacement?
Absolutely. Many people express a concern about a dislocation or damage  to the prosthesis while having intercourse after a hip replacement. After 10-12 weeks the pseudocapsule has reformed around the hip joint, and the  muscles typically have been rehabilitated so that the risk of a dislocation or damage to the prosthesis is negligible. Certainly, for patients who have had to cease coitus because of pain or a loss of ROM prior to hip surgery, the return of sexual activity should be one goal postoperatively.

31. Where are the most frequent sites of hip fracture in the elderly?
Femoral neck and the intertrochanteric and subtrochanteric areas.

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