As 10,000 baby boomers turn 65 each day, Nurse Practitioners (NPs) encounter an increasing number of issues associated with aging. One of these is osteoarthritis. Over 50% of those over 65 have osteoarthritis.   Approximately seven million people living in the United States have undergone hip or knee replacements and over one million joint replacements are performed annually. NPs treat adults who are post-arthroplasty and are in a prime position to address associated long-term issues.

The highest risk for short-term issues occurs within the first post-operative months, and symptoms that surface more than six months after surgery are generally considered long-term.  A logical process to evaluate long-term problems related to arthroplasty is to divide issues between either intrinsic or extrinsic to the joint prosthesis. The cornerstones of approaching musculoskeletal symptoms post arthroplasty are a thorough history and physical exam (http://www.npjournal.org/article/S1555-4155(15)00850-8/fulltext). Patient history includes symptoms that occurred pre-arthroplasty, patient expectations, any problem-free interval.  Did a change in activity level or injury contribute to new symptoms? Detail the pain character.  Is it triggered by ambulation or use of the affected limb?

The physical exam adds to the history and often determines if the symptoms are focal to the joint or another area (http://ortho-teaching.feinberg.northwestern.edu/teaching-videos-slides/Physical%20Exam%20Videos/index.html).   The affected joint should be taken through both active and passive range of motion. Assess if pain is provoked with resisted motion when measuring strength. A key point to assess for is specific tender areas over tendon or bursa locations.  Orthopedic tests specific to the affected joint should be included (https://www.youtube.com/watch?v=wlLfNls75RY; https://www.youtube.com/watch?v=iTfDvFCPZ_w ). It is beneficial to examine the lumbar spine as referred issues can cause symptoms in the hip and knee.  Observing gait can yield information regarding muscle imbalance and instability. Components of gait exam include stance phase, stride length, pelvic rotation, trunk shift, and foot position. Gluteal weakness results in Trendelenburg gait causing the hip to drop on contralateral side. Describing the fluidity of the gait or if it is altered by pain is a critical component of documentation (“Ambulation is antalgic with decreased fluidity of motion and slow cadence.”).

Problems intrinsic to the prosthesis include loosening/abnormal wear, material failure, implant fracture, and late infection. Implant fracture is rare and typically a result of trauma.  X-rays should be ordered for complaints of pain or instability. Signs suspicious for infection include erythema, swelling, and pain surrounding the joint.  The acute onset of pain in a previously sound joint prosthesis may be the only symptom of infection.  Laboratory testing (CBC, ESR, CRP) should be ordered if this is suspected. Timely diagnosis, testing, and referral can prevent unnecessary debility.  If infection goes undetected or becomes chronic, it can lead to subsequent arthroplasty revision, sepsis, and even amputation. Intrinsic issues are referred to the orthopedic surgeon. If sepsis is suspected and the patient cannot be seen by their orthopedist within one week they should be sent to the emergency room.

Diagnoses which are extrinsic to the joint are common and can often be successfully managed in the primary care setting.  Origins of pain extrinsic to the prosthesis include neurologic, tendon/muscle-related, and heterotopic ossification.  If symptoms are described as neuropathic in nature, EMG testing can determine etiology and chronicity (http://www.aanem.org/Patients/Find-a-Specialist ). If an issue is identified as either a peripheral nerve injury or radiculopathy, an appropriate plan of care can then be determined.  For patients with mild to moderate symptoms this generally starts with physical therapy and oral medication (neuropathic pain medication and/or anti-inflammatories); severe pain may require pain management to improve tolerance for rehabilitation. Refer to neurology if progressive weakness or neurologic deficits are present. Tendinopathy and muscular pain is common and often undiagnosed following arthroplasty. It is key to assess the anatomy of the joint, muscles, and tendons through a good physical exam. Pay attention to the location of scars as both scar tissue and tendons near scars can become painful.  A common example is hip flexor tendinosis, which is provoked with resisted hip flexion (test the patient with the knee flexed and extended). There is typically tenderness over the tendon origin as well.  Patients are frustrated as they seek the source of their symptoms. They feel as if their surgery was supposed to fix their squeaky wheel and yearn to reach their potential.  Treatment options for tendon and muscle pain include physical therapy, focal cortisone injections, and anti-inflammatories (oral and topical). Ultrasound guidance can improve accuracy of injection location, especially for deeper muscle and tendon areas.  Consider referral to a rehab or orthopedic specialist if improvement is not seen within a 6-8 week course of conservative treatment. Heterotopic ossification (HO) is a pathological bone formation in soft tissue and muscle following trauma or arthroplasty. HO presents with joint stiffness, decreased range of motion, and varying severity of pain. It is more common in those with a history of spinal cord injury, traumatic brain injury, and severe burn injury. It can be visualized on x-ray and should be referred to the orthopedic surgeon.

To reduce post-arthroplasty complications, NPs should encourage pre-surgery physical therapy and exercise to strengthen muscle groups and endurance. Patients who are followed closely postoperatively and have good social support adhere better to their rehabilitation plan. Remember to reiterate rehabilitation recommendations and provide long-term prophylactic antibiotics before all dental visits and procedures involving open orifices.

Arthroplasty has become commonplace in the United States. The aging population is staying active, and advancements in techniques have improved post-operative expectations.  Primary goals of arthroplasty are to maintain mobility and optimize the quality of life for individuals. Complications often lead to setbacks. Early recognition and treatment is a major factor in success.  NPs who encounter increased frequency of long-term complications can optimize the quality of life for their patients by focusing on functional goals and minimizing squeaky wheels.

Laurel Short, MSN, FNP-c is a Physical Medicine & Rehabilitation Nurse Practitioner in Overland Park, Kansas.  She can be reached at [email protected].

See Laurel Short, MSN, FNP-C speak in 2018 at a Skin, Bones, Hearts & Private Parts conference in Myrtle Beach, San Antonio, or Las Vegas.