CHAPTER SYNOPSIS:
Preoperative evaluation for total hip arthroplasty requires obtaining a thorough history and physical examination, the proper radiographic studies, and templating. The goals of preoperative evaluation are to select the proper patient and the appropriately sized implant that will restore the center of rotation of the hip, proper limb lengths, and femoral offset. Templating with company-specific templating guides helps predict what components will be used, but final determination of a successful outcome is subject to intraoperative variabilities and surgical experience.
IMPORTANT POINTS:
- 1
A comprehensive history and physical examination are critical.
- 2
Request medical clearance if necessary.
- 3
Assess preoperative hip function (Harris hip score).
- 4
Identify other potential sources of hip pain (spine or knee).
- 5
Evaluate patient’s medications (e.g., stop blood thinners).
- 6
Rule out infection.
- 7
Obtain proper anteroposterior and lateral view radiographs.
- 8
Know the magnification and rotation.
- 9
Perform careful acetabular and femoral templating.
- 10
Understand that intraoperative assessments overrule templating.
CLINICAL/SURGICAL PEARLS:
- 1
Hip pain caused by femoroacetabular arthritis usually presents as groin or anterior thigh pain.
- 2
Aspirin and other nonsteroidal antiinflammatory medications should be discontinued 7 to 10 days before surgery.
- 3
If infection is suspected, a complete blood count, erythrocyte sedimentation rate, C-reactive protein, and hip aspiration with culture should be performed.
- 4
Computed tomography can be helpful in complex cases and in patients with a history of previous hip fracture.
- 5
Femoral anteversion normally is 10 to 15 degrees; therefore anteroposterior views of the hip should be taken with the hip internally rotated 10 to 15 degrees.
- 6
Standard radiographs should be taken with the x-ray tube 100 cm from the top of the table and the x-ray tray 5 cm below the table.
- 7
Key landmarks in acetabular templating include the superolateral margin of the acetabulum (laterally), the ilioischial line (medially), and the base of the teardrop (inferiorly).
- 8
The coronal tilt of the acetabular cup should be 40 degrees of abduction.
- 9
If cement is being used, a 2- to 3-mm mantle should be implemented in the preoperative plan for both the acetabular and femoral component.
- 10
Femoral templating should focus on restoring limb length and femoral offset.
INTRODUCTION
Preoperative planning for total hip arthroplasty allows optimization of the strides made in the treatment of degenerative joint disease. Orthopedic surgeons are challenged with the task of acquiring the information and determining the important factors for a successful outcome in total hip arthroplasty. Improper planning can lead to excessive wear of components, fixation failure, limb-length discrepancy, and dislocation. Each of these modes of failure is multifactoral and depends on patient factors, materials, component design, component positioning, and bone quality. Also, the patient’s biologic response to wear debris can cause systemic reactions and pain. The surgeon must consider each of these factors to prevent failure of the components. Therefore having a preoperative plan can help decrease the amount of variability the surgeon will face in the operating room. This chapter discusses the most important components in preoperative evaluation, with the goal of improving operative efficiency and postoperative outcomes.
MEDICAL HISTORY
Several key components should be considered in the medical history and current medical status of the patient. The patient’s age, sex, preoperative diagnosis, activity level, and mental status can help determine which implant and approach should be used. Previous medical conditions, previous hip surgeries, history of infection or sepsis, and previous implant fixation around the hip also should be considered. Each of these can influence the success of the surgery. Hip pain is nonspecific and can come from several sources. True hip pain caused by osteoarthritis of the hip typically presents as groin or anterior thigh pain and usually is worse with activity and improves with rest and limited weight bearing. Measures to quantify an individual’s hip status objectively have been developed by Harris and can be used preoperatively and postoperatively to assess outcomes of the intervention. The patient’s preoperative functional status also can have an effect on the patient’s postoperative status and functional recovery. Holtzman et al found that patients with a worse preoperative status do not have as good an outcome as do patients with better function preoperatively. A history of substance abuse or neuromuscular disorders also can have a detrimental effect on implant stability and lead to dislocation. Su and Pellici have made the argument for constrained cups in primary total hip arthroplasty in individuals especially susceptible to dislocation, such as those with neuromuscular disorders or historically noncompliant patient populations.
Patient medications should be evaluated, especially if antiplatelet medications such as aspirin or antiinflammatory agents are being used. These should be discontinued 7 to 10 days before surgery. Robinson et al revealed that patients receiving nonsteroidal antiinflammatory drugs before hip arthroplasty had twice the blood loss of the control group. A report of previous or ongoing hip or systemic infection also should be ruled out. If the patient has a history of drainage from the hip or if signs of persistent infection are present on examination of the skin, appropriate laboratory investigations should proceed. These include a complete blood count, erythrocyte sedimentation rate, and C-reactive protein. Finally, joint aspiration and culture are advisable before surgery if infection is suspected.
Determining why the patient seeks joint replacement surgery is important to ensure goals are met postoperatively. Wright et al studied 72 patients and found that the two most important reasons for desiring a total hip arthroplasty were pain during the day and walking difficulties. They concluded that greater attention to the individual requirements of the patients might improve subjective patient satisfaction in total hip replacement and other orthopedic surgeries. Patient education classes also can be helpful. A prospective, randomized trial by Mancuso et al revealed that preoperative education classes have an effect and can modify patient expectations, leading to increased patient satisfaction.
PHYSICAL EXAMINATION
Standard clinical examination before total hip arthroplasty should be a step-by-step process that begins when the patient walks into the clinic with an observation of gait pattern and standing posture. Joint assessment is critical; it should include consideration of pathology from nearby regions and other joints that may contribute to hip pain. Both the lumbosacral spine and knee should always be assessed as potential sources of and contributors to hip pain. Pain located in the buttock or posterior pelvis, as opposed to the groin or anterior thigh, often is referred from the lumbosacral spine or sacroiliac joint. Pathology in these regions should be ruled out by plain radiographs. A common misconception is that hip pain does not radiate below the knee. However, Khan el al showed that hip pain from osteoarthritis usually manifests as groin or buttock pain but can radiate below the knee in the saphenous nerve distribution (which branches from the femoral nerve). The physical examination also should include limb-length discrepancy, abductor power (Trendelenburg test), both active and passive range of motion, flexion contractures, and examination of the contralateral hip. One of the first signs of osteoarthritis of the hip is limitation of internal rotation with the hip in flexion; however, pain that arises from the hip typically is elicited throughout all planes of hip motion, mainly at the extremes. Active straight-leg raising or resisted straight-leg raising may produce pain. Log rolling (internal and external rotation of the hip in extension) also can cause pain in severe cases of arthritis.
Limb-length discrepancies can be categorized as actual or functional. Actual limb-length discrepancies are determined by measuring the distance between the anterior-superior iliac spine and the medial malleolus. A functional limb-length discrepancy is what the patient perceives as his or her discrepancy and can be determined by placing blocks underneath the patient until the patient is subjectively even. A study by Cibere et al found that among 35 physical examination signs, limb-length inequality was one of the most reliable after standardization. Functional discrepancies commonly are caused by soft tissue contractures, whereas actual discrepancies usually are caused by bony pathology. Pelvic obliquity can be evaluated by comparing the pelvis with the patient sitting and standing. Pelvic obliquity caused by conditions above the pelvis (scoliosis or degenerative spinal condition) persists in the seated position. Conditions that occur at or below the pelvis (trauma, arthritis, infection) resolve when seated.
If multiple joints are found to have arthritic changes, a decision must be made regarding the order in which to address them. If a patient has both hip and knee arthritis that requires replacement, the hip should be addressed first because hip arthroplasty can change the alignment and mechanics of the knee. In the case of bilateral hip arthritis requiring total hip arthroplasty, no consensus has been reached regarding the sequence of addressing this pathology. Eggli et al found no increase in local or general complications after performing bilateral total hip arthroplasties during a single operative session and reported a decrease in costs by 30%. Others have found that complications after bilateral total hip arthroplasty in a single session were approximately 1.3 times more frequent than when unilateral hip arthroplasty was performed. Indications for single-stage bilateral total hip arthroplasty are medically fit patients with bilateral severe involvement with stiffness or fixed flexion deformity that may affect postoperative rehabilitation. Relative contraindications include elderly patients with comorbidities such as pulmonary disease, diabetes, and heart disease. Absolute contraindications include a documented patent ductus arteriosus or septal defect.
MEDICAL CONSULTATION
The preoperative medical evaluation of an orthopedic patient before total hip arthroplasty is an integral component in the process of assessing the patient’s risk before surgical intervention. Preoperative medical consultations prove beneficial to the patient, surgeon, and anesthesiologist through a variety of methods. From the standpoint of the patient, chronic or comorbid medical illnesses are assessed by the preoperative medical consultant to identify any unstable conditions that need further investigation, evaluation, and treatment. This medical optimization is recommended before an elective surgical procedure and leads to decreased perioperative morbidity and mortality. A thorough preoperative medical consultation also commonly identifies or diagnoses new medical conditions that may require intervention, additional workup, or consultation before pursuing an elective orthopedic procedure.
From the perspective of the surgeon, the medical consultation helps identify the confounding medical conditions that may lead to perioperative medical complications that could prolong hospital stay. It also identifies potential barriers to rehabilitation postoperatively that can frequently result in worse functional outcomes after joint arthroplasty. In addition, operating room efficiency, as measured by surgical delays and cancellations, is improved with preoperative medical consultation because appropriate medical issues are identified and optimized and additional necessary information is obtained before the day of surgery. Preoperative medical evaluations improve patient satisfaction, result in a reduction of unnecessary consultation and testing, and decrease the length of hospitalization.
The anesthesiologist also benefits from a thorough medical history and physical examination that identifies potential medical conditions that could lead to increased anesthetic risks. The identification of all comorbid illnesses allows appropriate preparation to manage these conditions if they deteriorate intraoperatively. As an integral component of risk stratification and assessment, the medical consultant will make a judgment regarding the necessary laboratory tests, studies, and additional consultations recommended before proceeding with an elective surgery. These decisions are made only by a thorough history and physical examination, evaluation of the patient’s baseline functional status, and review of the medical records. For example, perioperative cardiac ischemia is a source of increased morbidity and mortality for orthopedic patients. Numerous guidelines and studies have been published that address assessment of cardiovascular risks, including the American Heart Association (AHA) and American College of Cardiology (ACC) 2007 guidelines for perioperative risk assessment, among many others. The general consensus from the new AHA/ACC guidelines is that cardiac investigation and intervention should be limited to patients who would require this workup irrespective of the forthcoming surgery and testing recommended only in those patients for whom it would influence patient care or treatment. In addition, the medical consultant may make recommendations regarding perioperative medication management to minimize adverse consequences of medication use, including prescription, over-the-counter, and herbal medications. These preoperative medication recommendations may decrease perioperative bleeding complications, drug-drug interactions, glucose management issues, risk of venous thromboembolism, and medication-related delirium, especially in the geriatric orthopedic patient. These medication recommendations are primarily made through clinical experience, expert opinion, and theoretical benefit because of the lack of validated medical evidence. At times the preoperative consultant must decide for which patients to prescribe additional medications to either optimize current medical conditions or improve perioperative morbidity and mortality, such as the use of perioperative beta-blockers in patients with a cardiovascular disease history, abnormal stress test result, or increase cardiovascular risk index. The orthopedic surgeon will need to determine appropriate patients for medical consultation; in general, any patient with comorbid medical conditions should qualify for this assessment.
For the success and reduction in perioperative and postoperative complications, the surgeon must understand that the purpose of preoperative consultation is not for medical clearance but for an evaluation of the concurrent medical conditions. Surgeons and medical consultants must both play an integral role in implementing suggestions regarding the evaluation, management, and risk of medical complications for individual patients. The goal of the preoperative medical consultation is to provide optimal care of the patient, which is paramount in the preoperative consultation process and has a significant impact on patient recovery from demanding orthopedic procedures such as total joint arthroplasty.
RADIOGRAPHIC EXAMINATION
Standard radiographic evaluations should be obtained on the patient being evaluated for total hip arthroplasty. These views include an anteroposterior (AP) view of the pelvis centered over the pubic symphysis. This AP view should include a substantial amount of the femur to allow accurate templating ( Fig. 3-1, A ). Next, attention should be paid to the affected hip, in which AP and true lateral views should be obtained. The lateral view also should allow for a lateral view of the femur and view of the acetabulum. Either a frog-leg lateral or cross-table lateral view can be obtained to evaluate the hip and femur (see Fig. 3-1, B ). An alternative view is the Lowenstein lateral view of the hip, which can be technically less difficult to obtain. The Lowenstein view requires the patient to be turned onto the affected hip at least 45 degrees to allow the lower limb to be in abduction, in external rotation, and flat on the table ( Fig. 3-2 ). If an old fracture or dislocation of the pelvis is reported, obturator and iliac oblique views should be obtained in addition to previously mentioned films. Computed tomography also can be helpful in more complex cases and has been shown to help determine the adequacy of acetabular depth, anterior acetabular coverage, and thickness of the anterior and posterior walls. Lateral radiographs of the proximal femur may reveal significant anterior bowing that may be present in individuals with Paget disease, old fractures of the femoral shaft, or congenital abnormalities. This bowing may require femoral osteotomy during or before surgery.
