INTRODUCTION TO PATIENT SELECTION IN TOTAL HIP ARTHROPLASTY
Total hip arthroplasty (THA) is widely regarded as one of the most successful surgical interventions in modern medicine, offering profound pain relief and functional restoration for patients with end-stage hip pathology. However, it remains a major surgical undertaking associated with a significant spectrum of potential complications and a baseline perioperative mortality rate of 1% to 2% in unoptimized populations. Consequently, the decision to proceed with THA must be predicated on a rigorous, evidence-based preoperative evaluation.
When THA is indicated, patients must be systematically evaluated for systemic disorders and general debility that may contraindicate an elective major operation. Preoperative medical consultation is not merely recommended; it is a mandatory component of the multidisciplinary approach to joint reconstruction. A substantial number of patients present with unsuspected, unoptimized comorbidities—such as occult cardiac ischemia, pulmonary insufficiency, hepatic dysfunction, genitourinary infections, metabolic derangements, uncontrolled hypertension, or undetected malignancies—that require definitive correction prior to surgical intervention.
CONTRAINDICATIONS IN TOTAL HIP ARTHROPLASTY
The identification of contraindications is the first critical step in the algorithmic approach to THA. Proceeding with elective arthroplasty in the face of absolute contraindications exposes the patient to catastrophic morbidity and mortality.
Absolute Contraindications
In contemporary orthopedic practice, specific, absolute contraindications for total hip arthroplasty include:
* Active Sepsis: Active infection of the hip joint, or any remote systemic infection (e.g., untreated dental abscess, pneumonia, active urinary tract infection), absolutely precludes elective arthroplasty due to the high risk of hematogenous seeding of the implant.
* Unstable Medical Illness: Any unstable cardiopulmonary or metabolic condition (e.g., recent myocardial infarction within 6 months, unstable angina, decompensated congestive heart failure, severe aortic stenosis) that significantly increases the risk of perioperative mortality.
* Documented Cardiac Shunts: In the context of simultaneous bilateral THA, a documented patent ductus arteriosus or ventricular/atrial septal defect is an absolute contraindication due to the risk of paradoxical fat embolism syndrome during femoral canal preparation.
Clinical Pearl: According to the foundational principles established by Sir John Charnley, THA can be performed in the presence of a chronic, low-grade infection in the opposite hip, provided the operative hip is sterile and the patient is under appropriate antimicrobial management. However, this remains a high-risk scenario requiring meticulous infectious disease coordination.
Relative Contraindications
Relative contraindications require the surgeon to weigh the potential benefits of the procedure against a significantly elevated risk profile. These include:
* Rapidly Progressive Bone Destruction: Conditions causing massive, rapid osteolysis may compromise implant fixation and require complex reconstructive techniques (e.g., custom triflange acetabular components or proximal femoral replacements).
* Neuropathic (Charcot) Arthropathy: The absence of protective proprioception and pain sensation leads to premature catastrophic implant failure, accelerated polyethylene wear, and aseptic loosening.
* Abductor Mechanism Insufficiency: An absence or severe insufficiency of the abductor musculature (gluteus medius and minimus) will result in a persistent, debilitating Trendelenburg gait and a high risk of postoperative instability and dislocation. Constrained liners or dual-mobility constructs may be required if surgery is pursued.
* Progressive Neurological Diseases: Conditions such as advanced Parkinson's disease, multiple sclerosis, or severe dementia complicate postoperative rehabilitation and dramatically increase the risk of dislocation.
PREOPERATIVE EVALUATION AND MEDICAL OPTIMIZATION
Careful patient evaluation before surgery is paramount because postoperative complications can be catastrophic or fatal. The primary clinical question must always be: Is the patient’s pain and functional deficit sufficient to justify a major elective operation?
The surgeon must assess whether the patient’s life expectancy is reasonable and whether their general condition is robust enough to tolerate major surgery involving significant fluid shifts and potential blood loss.
Systemic Assessment and Medication Management
A thorough general medical evaluation, including comprehensive laboratory testing, electrocardiography, and chest radiography, is a recognized prerequisite. This affords the clinician the opportunity to uncover and treat subclinical problems.
* Anticoagulant and Antiplatelet Management: Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) should generally be discontinued 7 to 10 days before surgery to normalize platelet function. Oral anticoagulants (e.g., Warfarin, DOACs) must be discontinued in sufficient time for bleeding and clotting parameters (PT/INR, aPTT) to return to baseline, often requiring bridging therapy with low-molecular-weight heparin (LMWH) in high-risk patients.
* Herbal and Nutritional Supplements: Many herbal medications (e.g., Ginkgo biloba, Ginseng, Garlic, Vitamin E) can cause profound perioperative coagulopathy and increased blood loss. These must be discontinued at least two weeks preoperatively.
* Concomitant Surgical Procedures: Patients requiring transurethral resection of the prostate (TURP) for benign prostatic hyperplasia should have that surgery completed and fully healed before elective arthroplasty to eliminate the risk of transient bacteremia seeding the new joint.
* Skin and Soft Tissue: Pyogenic skin lesions, cellulitis, or severe stasis dermatitis in the operative extremity must be eradicated prior to incision.
Evaluating for Occult Infection
If a patient has a history of purulent drainage from the hip, prior hardware placement, or other indications of ongoing indolent infection, an aggressive preoperative workup is mandatory.
* Appropriate laboratory investigations (ESR, CRP, CBC with differential).
* Nuclear imaging (e.g., Indium-111 labeled white blood cell scans).
* Fluoroscopically or ultrasound-guided aspiration of the hip for cell count, culture, and sensitivity.
Surgical Warning: Infection must be highly suspected if preoperative radiographs demonstrate erosion of the subchondral bone of the acetabulum or femoral head, or if there is focal endosteal scalloping and bone resorption around an existing internal fixation device.
CLINICAL EXAMINATION AND BIOMECHANICAL ASSESSMENT
Differentiating Hip Pathology from Referred Pain
The complaint of "hip pain" is a non-specific symptom complex brought about by a variety of afflictions; isolated osteoarthritis of the hip joint is only one potential etiology.
* True Hip Joint Pain: Typically perceived deep in the groin, occasionally radiating to the anterior thigh, and frequently referred to the medial knee via the obturator nerve. Arthritic pain is exacerbated by weight-bearing and rotational activities and improves with rest.
* Referred Pain: Pain located in the buttock, posterior pelvis, or lateral thigh is often referred from the lumbar spine (radiculopathy), sacrum, sacroiliac joint, or represents trochanteric bursitis.
Arthritis frequently coexists in the hip and lumbar spine (Hip-Spine Syndrome). Performing a THA to relieve symptoms predominantly referred from a stenotic lumbar spine will result in a dissatisfied patient. Surgical intervention in the face of mild hip arthritis when the pain is actually caused by unrecognized vascular claudication, pubic ramus fracture, or intra-abdominal pathology subjects the patient to needless risk.
Physical Examination and Spinopelvic Biomechanics
The physical examination must systematically evaluate the spine, upper extremities (for reliance on assistive devices), and lower extremities.
* Soft Tissue Inspection: The soft tissues around the hip must be inspected for inflammation, prior surgical scarring, or compromised vascularity where the incision is planned.
* Abductor Strength: The integrity of the abductor musculature is determined by the Trendelenburg test. A positive test indicates abductor weakness, which must be factored into the surgical approach and implant selection.
* Leg Length Discrepancy (LLD): The lengths of the lower extremities must be meticulously compared.
* Adduction contracture of the hip produces an apparent shortening of the limb despite equal true leg lengths.
* Abduction contracture produces an apparent lengthening.
* Spinopelvic Alignment: This is a critical, advanced concept in modern THA. A fixed flexion deformity of the hip forces the lumbar spine into hyperlordosis upon assuming an upright posture, aggravating lower back pain. Conversely, a fixed lumbar spine deformity (e.g., from severe scoliosis, multi-level fusion, or ankylosing spondylitis) produces pelvic obliquity. This alters the functional anteversion and inclination of the acetabulum. The surgeon must account for this altered spinopelvic kinematics when positioning the acetabular component to prevent postoperative impingement and dislocation.
Clinical Pearl: When a patient presents with severe, symptomatic osteoarthritis of both the hip and the knee on the same ipsilateral side, the hip should almost always be operated on first. Hip arthroplasty alters the mechanical axis and alignment of the lower extremity, which dictates the subsequent bone cuts in total knee arthroplasty. Furthermore, knee rehabilitation is severely hampered if the ipsilateral hip remains stiff and painful.
SURGICAL PLANNING, POSITIONING, AND APPROACHES
While the choice of surgical approach depends on surgeon experience and patient anatomy, a thorough understanding of the biomechanics and step-by-step execution is required for optimal outcomes.
Patient Positioning
- Lateral Decubitus Position: Utilized primarily for the Posterior and Anterolateral approaches. The patient is secured with pelvic positioners (e.g., peg board or specialized clamps). Meticulous padding of all bony prominences (peroneal nerve at the fibular head, axilla) is mandatory to prevent neuropraxia. The pelvis must be strictly orthogonal to the floor to ensure accurate intraoperative estimation of acetabular cup version and inclination.
- Supine Position: Utilized for the Direct Anterior approach, often on a specialized orthopedic traction table. This allows for intraoperative fluoroscopy to precisely gauge component positioning and leg length restoration in real-time.
Surgical Approaches: Step-by-Step Overview
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The Posterior Approach (Moore/Southern):
- Incision: Curved incision centered over the greater trochanter.
- Superficial Dissection: Split the gluteus maximus bluntly in line with its fibers.
- Deep Dissection: Identify and protect the sciatic nerve. Tag and release the short external rotators (piriformis, superior gemellus, obturator internus, inferior gemellus) and the quadratus femoris near their femoral insertions.
- Capsulotomy: Perform a T-shaped or I-shaped capsulotomy to expose the femoral head.
- Advantage: Excellent extensile exposure; preserves the abductor mechanism.
- Disadvantage: Historically associated with a higher rate of posterior dislocation, though enhanced soft-tissue repair techniques have mitigated this risk.
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The Direct Anterior Approach (Smith-Petersen):
- Incision: Longitudinal incision starting distal and lateral to the anterior superior iliac spine (ASIS).
- Superficial Internervous Plane: Between the tensor fasciae latae (superior gluteal nerve) and the sartorius (femoral nerve).
- Deep Internervous Plane: Between the gluteus medius (superior gluteal nerve) and the rectus femoris (femoral nerve).
- Advantage: True internervous and intermuscular plane, potentially allowing for faster early mobilization and lower dislocation rates.
- Disadvantage: Steep learning curve; risk of lateral femoral cutaneous nerve (LFCN) neuropraxia; difficult femoral exposure in muscular or obese patients.
SIMULTANEOUS BILATERAL TOTAL HIP ARTHROPLASTY
In specific clinical scenarios, operating on both hips during a single anesthetic session may be indicated. Pioneers such as Charnley and Salvati demonstrated the feasibility of this approach. Recent literature (Eggli, Huckell, Ganz) suggests that in highly selected patients, there is no significant increase in local or general complications compared with staged procedures, while overall healthcare costs are reduced by up to 30%. Conversely, other studies (Macaulay et al.) report a 1.3-fold increase in systemic complications.
Indications and Contraindications for Bilateral THA
- Major Indication: A medically fit, physiologically young patient with severe bilateral hip involvement characterized by profound stiffness or fixed flexion contractures. In such cases, staging the procedures makes rehabilitation of the first hip nearly impossible due to the severe contralateral deformity.
- Contraindications: Elderly patients (>75 years) or those with cardiopulmonary comorbidities (ischemic heart disease, pulmonary insufficiency, diabetes mellitus) are strictly not candidates. As previously noted, a documented patent ductus arteriosus or septal defect is an absolute contraindication due to the risk of paradoxical embolization during bilateral femoral canal pressurization.
Intraoperative Management
Simultaneous bilateral THA demands intensive intraoperative hemodynamic monitoring.
* An arterial line for continuous blood pressure monitoring.
* A central venous catheter or pulmonary artery catheter in selected cases to monitor volume status and right heart pressures.
* A urinary catheter to monitor end-organ perfusion.
* The surgical and anesthesia teams must maintain continuous dialogue. The decision to proceed with the second hip must be actively re-evaluated after the completion of the first side, based on blood loss, hemodynamic stability, and operative time.
POSTOPERATIVE PROTOCOLS AND OUTCOME EVALUATION
Anesthesia and Pain Management
General inhalation anesthesia, continuous epidural blocks, or spinal anesthesia can be utilized. Regional anesthesia (spinal/epidural) is highly preferred when not contraindicated, as it reduces intraoperative blood loss, lowers the incidence of deep vein thrombosis (DVT), and provides superior early postoperative analgesia.
Clinical Rating Systems
To objectively evaluate the success of the arthroplasty, standardized rating systems must be employed. The Harris, Iowa (Larson), Judet, Andersson, and d’Aubigné and Postel systems record the status of the hip preoperatively and postoperatively.
The Harris Hip Score (HHS) is the most universally utilized metric. It evaluates:
1. Pain (44 points)
2. Function and Gait (47 points)
3. Absence of Deformity (4 points)
4. Range of Motion (5 points)
While rating systems are invaluable for academic reporting, they have been criticized for subjectivity and for occasionally emphasizing raw range of motion over true functional capability. Improved arc of motion is of little clinical benefit if the patient remains unable to perform activities of daily living, such as dressing their feet or trimming their toenails.
Surgical Pitfall: Failure to manage patient expectations is a primary cause of postoperative dissatisfaction, even in the presence of a radiographically perfect implant. A frank, documented preoperative discussion regarding the realistic goals of the operation—including the potential for residual stiffness, leg length discrepancies, or the need for lifelong activity modifications—is absolutely essential.
Conclusion
Total hip arthroplasty is a masterclass in biomechanical engineering and surgical precision. However, the ultimate success of the procedure is dictated long before the first incision is made. Through exhaustive preoperative evaluation, rigorous medical optimization, and a profound understanding of spinopelvic kinematics, the orthopedic surgeon can navigate complex contraindications and deliver life-altering functional restoration to the arthritic patient.
