Bradley Ashman, MD, David Cruikshank, MD, Michael Moran, MBBCh, FRCSC Total hip replacement: Relieving pain and restoring function Since the first successful modern hip arthroplasty was performed by Sir John Charnley in the 1960s, procedures and components have evolved and made joint replacement available to patients younger than 65. ABSTRACT: Total hip replacement metal or ceramic femoral heads; and otal hip replacement is a re- is one of the most common ortho- polyethylene or ceramic acetabular markable procedure that can paedic reconstructive procedures liners. In British Columbia, the stan- Trelieve pain and restore func- performed today, with more than dard of care is a metal acetabular tion. According to the Canadian Insti- 40 000 replacements completed an- shell with a polyethylene liner and tute for Health Information, more than nually in Canada. New surgical tech- a cemented or uncemented femoral 40 000 hip replacements are complet- niques and materials have led to stem with a metal femoral head. Hip ed annually in Canada (https://secure procedures that produce profound resurfacing is an option for young .cihi.ca/estore/productFamily.htm? changes in the lives of patients and active patients, although its use locale=en&pf=PFC2945&lang=en). allow them to resume virtually all of worldwide has declined dramatical- For most patients with a destructive their previous activities. Sir John ly. Early mobilization after total hip process occurring in the hip joint, to- Charnley developed low-friction ar- replacement is recommended. While tal hip arthroplasty (THA) is a viable throplasty in the 1960s. Since then, complication rates are low, possible option. Since the first successful THA procedures have evolved to address postoperative problems include ve- was performed in the 1960s, proce- the issues of wear and bone loss and nous thromboembolism and nerve dures and the components used have permit joint replacement in patients injury in the short-term, and peri- evolved and we now have a better un- younger than 65. Pain is the prima- prosthetic fracture and osteolysis in derstanding of post-op considerations ry indication for a hip replacement, the long-term. If there is a failure of and possible complications. with osteoarthritis being the most the hip replacement for some rea- common cause. State-of-the-art im- son, the likelihood of a revision pro- History plants in 2016 include cemented, cedure succeeding is good. Beginning in the 1800s, a number of uncemented, or hybrid components; attempts were made at hip replace- ment for infection and fracture using implants of ivory, glass, ceramic, and metal. These trials continued through to the 1960s, when Sir John Charnley Drs Ashman and Cruikshank are residents in the Department of Orthopaedics at the University of British Columbia. Dr Moran is an orthopaedic surgeon at the University Hospital of Northern BC and a clinical pro- fessor in the Department of Orthopaedics This article has been peer reviewed. at the University of British Columbia. BC MEDICAL JOURNAL VOL. 58 NO. 9, NOVEMBER 2016 bcmj.org 505 Total hip replacement: Relieving pain and restoring function developed the modern total hip often. These include metal-on-metal been resolved. Patients unable to per- replacement, which he called low- and ceramic-on-ceramic bearing sur- form activities of daily living or with friction arthroplasty.1 Charnley’s faces. While the risk of wear is mini- deformities such as a leg-length dis- procedure used a single-component mal with these articulations, metal- crepancy or flexion deformity are (monoblock) metal femoral stem and on-metal total hip arthroplasty has prime candidates for this operation. head combined with a cemented poly- been abandoned because of the many Such patients tend to have significant ethylene acetabular shell. The arthro- failures related to adverse local tissue pain. With the improving outcomes plasty of Charnley’s era survived for reactions to metal debris and the for- of hip replacement it is no longer many years but had problems. The mation of pseudotumors. Currently, necessary to wait until patients are 22.25-mm femoral head was prone the only hard-on-hard bearing surface completely disabled before consid- ering surgery. Earlier intervention yields better outcomes provided that nonoperative treatments are no lon- ger effective and the patient has pain that is related to the hip joint and not referred from the lumbar spine or With the improving outcomes related to extra-articular structures. of hip replacement it is no Pain from the hip joint is typi- cally located in the groin or buttock, longer necessary to wait until with referral to the thigh and often patients are completely disabled to the knee. Hip arthritis can present solely with knee pain, a finding espe- before considering surgery. cially common in elderly patients. All patients presenting with knee pain should undergo a physical examina- tion of the hip and appropriate radio- graphs should be obtained if abnor- malities are found during the hip to dislocation and the polyethylene available for a total hip arthroplasty examination. shell to eccentric wear. Larger femo- is ceramic-on-ceramic, and accord- ral heads were developed that reduced ing to joint registry data there is no Diagnoses the rate of dislocation, but at the cost evidence of superiority when ceramic Obviously, patients being considered of increased wear. Whatever the size and highly crosslinked polyethylene for THA need to have an underlying of the head, the cement mantle tended are compared at 10 years follow-up. condition that can be addressed using to loosen and then fail. The problem Today’s state-of-the art implants joint replacement. In broad terms, any of loosening was essentially solved include: patient with a pathology that leads to with the introduction of uncemented • Femoral heads of metal or ceramic. degeneration of the articular carti- components. However, failures con- • Acetabular liners of polyethylene or lage of the joint might benefit from tinued to occur with the breakdown ceramic. replacement of that joint. Osteoar- of the polyethylene and subsequent • Components that are cemented, un- thritis, whether idiopathic, develop- bone loss. cemented, or hybrid (uncemented mental, or posttraumatic, is by far Since the late 1990s, highly cross- acetabulum and cemented femur). the most common diagnosis lead- linked polyethylene with much im- ing to hip replacement surgery. This proved wear characteristics has been Indications includes osteoarthritis in the medial used with excellent results. Today The primary indication for total hip wall of the acetabulum, which is often wear and bone loss as a result of hip replacement is pain. Patients who are missed because the radiological find- replacement are exceedingly rare, unable to sleep because of pain will ings can be subtle and the presenting regardless of patient age or activity generally have a remarkable outcome symptoms can be somewhat unusu- level. In addition, so-called hard-on- from THA and will likely awake from al. For example, a patient may have hard articulations are being used more surgery to realize that their pain has pain at night and with certain activi- 506 BC MEDICAL JOURNAL VOL. 58 NO. 9, NOVEMBER 2016 bcmj.org Total hip replacement: Relieving pain and restoring function A B Figure 1. Anteroposterior view of left hip (A) shows minor changes at the dome of the acetabulum and difficult-to-assess osteoarthritis (solid arrow) in the acetabular medial wall. Lateral view of the left hip (B) reveals osteoarthritis (dashed arrow) in the acetabular medial wall. ties because the medial wall of the hip will rarely change the manage- collapse and cause degeneration of the acetabulum is affected, but can still ment and should not be ordered if hip joint. However, the radiological have good walking tolerance because there is any evidence of degenera- findings are often not as pronounced the dome of the acetabulum (the tive arthritis. Hip-preserving surgery as the patient symptoms. MRI will weight-bearing surface) is relatively (hip arthroscopy or open dislocation reveal the extent of the disease but is unaffected. In these cases, the lateral and debridement) in the presence of not usually a necessary investigation radiograph can be helpful in assessing degeneration will not lead to a good unless the plain X-ray images do not medial wall osteoarthritis ( Figure 1 ). outcome and may lead to more rapid reveal any abnormalities early in the Over the past decade femoroac- progression of the arthritis and an ear- course of the disease. etabular impingement (FAI) has been lier need for a hip replacement. Inflammatory arthropathies such recognized as a precursor of and pos- Acetabular dysplasia involves a as rheumatoid arthritis, ankylosing sibly one of the ultimate causes of shallow or underdeveloped acetabu- spondylitis, and psoriatic arthritis all idiopathic osteoarthritis of the hip. lum that leads to early hip osteoar- present with degenerative changes The condition commonly occurs as thritis. As in cases of femoroacetabu- similar to those seen in osteoarthri- either cam FAI (deformity of the fem- lar impingement, patients older than tis and should be treated in the same oral neck) or pincer FAI (deformity 40 with acetabular dysplasia will not manner. of the acetabulum). The impingement benefit from osteotomies and labral caused by deformed hip bones even- repairs. The only effective surgi- Age tually leads to acetabular labral tears cal option is a total hip replacement. In the past, being younger than 65 and concomitant articular cartilage As such, there is no role for MRI in was considered a barrier to joint degeneration. Because the labral tears diagnosing acetabular dysplasia and replacement. This is no longer the are part of the degenerative process, degenerative change. case. Although patients with hip- the repair of these in patients older Avascular necrosis occurs when related pain should be counseled to than 40 without a bona fide injury the blood supply to the femoral head persist with nonoperative treatment and FAI is almost never indicated.