Total Hip Arthroplasty – Indications, Contraindication

Total Hip Arthroplasty (THA) is one of the most cost-effective and consistently successful surgeries performed in orthopedics.  THA provides reliable outcomes for patients’ suffering from end-stage degenerative hip osteoarthritis (OA), specifically pain relief, functional restoration, and overall improved quality of life. Other underlying diagnoses include hip osteonecrosis (ON), congenital hip disorders, and inflammatory arthritis[rx][rx][rx]

Total hip arthroplasty, or surgical replacement of the hip joint with an artificial prosthesis, is a reconstructive procedure that has improved the management of those diseases of the hip joint that have responded poorly to conventional medical therapy.

Anatomy of Total Hip Arthroplasty

The hip is a ball-and-socket type diarthrodial joint. Hip joint stability is achieved via a dynamic interplay from osseous and soft tissue anatomic components. Osseous components include the proximal femur (head, neck, trochanters), and the acetabulum, which is formed from 3 separate ossification centers (the ilium, ischium, and pubic bones). The native acetabulum is oriented in 15 to 20 degrees of anteversion and 40 degrees of abduction. The femoral neck is oriented in 15 to 20 degrees of anteversion and is angled 125 degrees with respect to its diaphysis[rx].

Soft tissue structures involved in hip joint stability include the labrum and joint capsule. The iliofemoral ligament (IFL) is the strongest of the 3 divisions of capsular ligaments. The IFL functions to restrict extension and external rotation of the hip. The other 2 components are the ischiofemoral and pubofemoral ligaments. The acetabular labrum is anchored at the periphery of the outer rim and functions to maintain negative joint pressure and deepen the hip socket[rx].

Types and Approaches of Total Hip Arthroplasty

There are several different surgical approaches described in the literature[rx]

Posterior 

The posterior (Moore or Southern) approach accesses the joint and capsule through the back, taking piriformis muscle and the short external rotators of the femur. This approach gives excellent access to the acetabulum and femur and preserves the hip abductors and thus minimizes the risk of abductor dysfunction postoperatively. It has the advantage of becoming a more extensile approach if needed. Critics cite a higher dislocation rate, although repair of the capsule, piriformis, and the short external rotators along with the use of modern large diameter head balls reduces this risk. Limited evidence suggests that the posterior approach may cause less nerve damage.^[rx]

Posterolateral

This is the most common approach for primary and revision THA cases. This dissection does not utilize a true inner nervous plane. The intermuscular interval involves blunt dissection of the gluteus maximus fibers and sharp incision of the fascia lata distally. The deep dissection involves meticulous dissection of the short external rotators and capsule. Care is taken to protect these structures as they are later repaired back to the proximal femur via trans-osseous tunnels.

Anterior 

The DA approach is becoming increasingly popular among THA surgeons. The inner nervous interval is between the tensor fascia lata (TFL) and sartorius on the superficial end, and the gluteus medius and rectus femoris (RF) on the deep side. DA THA advocates cite the theoretical decreased hip dislocation rates in the postoperative period and the avoidance of the hip abduction musculature.

Anterolateral

Compared to the other approaches, the anterolateral (AL) approach is the least commonly used approach secondary to its violation of the hip abductor mechanism. The interval exploited includes that of the TFL and gluteus medius musculature; this may lead to a postoperative limp at the tradeoff of a theoretically decreased dislocation rate.

Lateral 

The lateral approach is also commonly used for hip replacement. The approach requires elevation of the hip abductors (gluteus medius and gluteus minimus) to access the joint. The abductors may be lifted up by osteotomy of the greater trochanter and reapplying it afterward using wires (as per Charnley) or may be divided at their tendinous portion, or through the functional tendon (as per Hardinge) and repaired using sutures. Although this approach has a lower dislocation risk than the posterior approach, critics note that occasionally the abductor’s muscles do not heal back on, leading to pain and weakness which is often very difficult to treat.

Minimally invasive approaches

The dual incision approach and other minimally invasive surgery seek to reduce soft tissue damage by reducing the size of the incision. However, component positioning accuracy and visualization of the bone structures can be significantly impaired as the approaches get smaller. This can result in unintended fractures and soft tissue injury. The majority of current orthopedic surgeons use a “minimally invasive” approach compared to traditional approaches which were quite large comparatively.

Indications of Total Hip Arthroplasty

The most common indication for THA includes end-stage, symptomatic hip OA. In addition, hip ON, congenital hip disorders including hip dysplasia, and inflammatory arthritic conditions are not uncommon reasons for performing THA. Hip ON, on average, presents in the younger patient population (35 to 50 years of age) and accounts for approximately 10% of annual THAs [rx].

Total hip replacement is most commonly used to treat joint failure caused by osteoarthritis. Other indications include

• Rheumatoid arthritis
• Avascular necrosis
• Traumatic arthritis
• Protrusio acetabuli
• Certain hip fractures
• Benign and malignant bone tumors
• Arthritis associated with Paget’s disease
• Ankylosing spondylitis and juvenile rheumatoid arthritis.
• The aims of the procedure are pain relief and improvement in hip function.
• Hip replacement is usually considered only after other therapies, such as physical therapy and pain medications, have recently failed.

Contraindications of Total Hip Arthroplasty

THA is contraindicated in the following clinical scenarios

• Local – Hip infection or sepsis
• Remote – (i.e. extra-articularticular) active, ongoing infection or bacteremia
• Severe cases – of vascular dysfunction

Equipment

Historical Timeline 

THA prosthetic designs have been evolving since the late 1800s when Dr. Themistocles Gluck continuously experimented with various options for joint replacements in preliminary animal experiments.  In 1890, one of Dr. Gluck’s reported 14 total joint arthroplasties included an ivory femoral head replacement in a human patient. In 1940, Dr. Austin Moore collaborated with trauma surgeon Dr. Harold Bohlman in developing the first hip hemiarthroplasty (endoprosthesis) for the treatment of displaced femoral neck fractures. In 1952, Dr. Moore developed his prestigious, “Austin Moore prosthesis” as an off-the-shelf joint replacement available worldwide. Sir John Charnley entered the scene in the 1960s when he introduced the concept of “low-friction arthroplasty” by utilizing a metallic femoral stem and small femoral head articulating with a cemented polyethylene acetabular component.[rx][rx]

Titanium in medical applications

Titanium is a better alternative to steel in medical implants because of improved biocompatibility, the strength to density ratio, corrosion resistance, and a lower modulus of elasticity. Titanium alloys further enhance the properties of pure titanium and are classified according to microstructure as alpha (α), near-(α), alpha-beta (α-β), metastable β, and stable β. β alloys are best for use in the medical field because of higher strength, superior corrosion resistance, and low elastic modulus. The most common β alloy is Ti-6AL-4V, which additionally contains aluminum (an α phase stabilizer) and vanadium (a β phase stabilizer).

Modern Implants and Bearing Surfaces

Contemporary THA techniques have evolved into press-fit femoral and acetabular components. In general, femoral stems can be categorized into the following general designs:

• Press-fit, proximally coated, distal taper (dual or single tapered in medial-lateral and/or anterior-posterior planes)
• Press-fit, extensively coated, diaphyseal engaging
• Press-fit, Modular stems: Modularity junction options include: (1) head-neck, (2) neck-stem, (3) stem-sleeve, and (4) mid-stem
• Cemented femoral stems: Cobalt-chrome stems are the preferred material to promote cement bonding[rx][rx]

Options for bearing surfaces include

• Metal-on-polyethylene (MoP) – MoP has the longest track record of all bearing surfaces at the lowest cost
• Ceramic-on-polyethylene (CoP) – becoming an increasingly popular option
• Ceramic-on-ceramic (CoC) – CoC has the best wear properties of all THA bearing surfaces
• Metal-on-metal (MoM) – Although falling out of favor, MoM has historically demonstrated better wear properties from its MoP counterpart. MoM has lower linear-wear rates and a decreased volume of particles generated. However, the potential for pseudotumor development as well as metallosis-based reactions (type-IV delayed hypersensitivity reactions) has resulted in a decline in the use of MoM. MoM is also contraindicated in pregnant women, patients with renal disease, and patients at risk of metal hypersensitivity[rx][rx]

One THA prosthesis includes a press-fit acetabular component, neutral polyethylene liner, and either an MoP, CoP, or CoC head/liner construct depending on patient age and projected activity level. In addition, patients with poor bone quality are often considered for a cemented femoral stem option. This concept is particularly relevant in the THA treatment for active, elderly patients with displaced femoral neck fractures.

Preparation of Total Hip Arthroplasty

Nonoperative Treatment Modalities

According to the most recent American Academy of Orthopaedic Surgeons’ (AAOS) Guidelines for the treatment of symptomatic osteoarthritis of the hip or knee, strong or moderately strong recommendations for nonoperative treatment was endorsed for the following modalities:

• Weight loss programs

  • indicated as first-line treatment for all patients with symptomatic hip arthritis
  • indication emphasized in all patients with a BMI greater than 25
• Physical activity and physical therapy programs
• Non-steroidal anti-inflammatory medications (NSAIDs) and tramadol[rx][rx]

Corticosteroid injections can be therapeutic and/or diagnostic for symptomatic patients. This modality can be particularly beneficial in patients when confounding conditions of lower back pain and lumbar spinal stenosis with or without radicular symptoms[rx][rx][rx] potentially add clinical ambiguity to the diagnostic workup.  In addition, a walking cane has the ability to decrease the joint reaction forces generated in the hip. When patients present with unilateral hip pain, they should be instructed to use the cane with the contralateral upper extremity.[rx][rx][rx]

Other modalities for symptomatic management that were not supported but are often considered reasonable alternative treatment measures to help manage symptoms secondary to hip arthritis include but are not limited to acupuncture, viscoelastic joint injections, and glucosamine and chondroitin supplements.

Preoperative Evaluation: Clinical Examination

A comprehensive history and physical examination are required prior to considering performing a THA in any patient. Patients should be questioned about prior interventions and treatments. Prior joint replacements, arthroscopic procedures, or other surgeries around the hip should be considered as prior surgical incisions or the presence of hardware in the femur or acetabulum can significantly impact the planned surgery and/or prosthesis design utilized.  In addition, a comprehensive medical evaluation should also be performed, and medical clearance and risk stratification are recommended for all patients prior to THA consideration [rx][rx]

Other considerations include patient body habitus, prior functional activity and goals/expectations following surgery, the pattern of arthritic involvement, and any history of prior hip trauma. The hip should be inspected for any skin discoloration, wounds, or previous scars. The soft tissues should be examined for evidence of gross atrophy, overall symmetry, and stability.  Atypical leg discomfort and pain at rest are common symptoms of peripheral vascular disease (PVD).  While up to 50% of patients are estimated to be asymptomatic at presentation[rx], clinical suspicion of PVD may warrant preoperative vascular surgery consultation.

Physical examination also includes an evaluation of the mechanical axis and overall alignment of the limb. It is critical to ensure spine and/or knee pathology is ruled out or at least considered prior to performing any surgery around the hip. Any leg length discrepancy (LLD) should also be noted. It is critical to also consider the impact of any of the following conditions in addition to actual or apparent LLD:

• Hyperlordotic spine conditions
• Pelvic obliquity
• Hip flexion contractures: The patient may not be able to stand upright
• Trendelenburg gait or Trendelenburg sign

A preoperative range of motion (ROM) should also be noted. Patients with end-stage arthritis more frequently present with a combination of hip adduction and flexion contractures. Any appreciable flexion contracture greater than 5 degrees and lack of flexion beyond 90 to 100 degrees should be documented. In addition, rotational arc ROM is typically limited, especially in the internal rotation. The neurovascular exam should also include the positive/negative status of a straight leg raise test.

Preoperative Evaluation: Radiographs

Preoperative radiographs, including a standing anteroposterior (AP) pelvis plus AP/lateral of the involved hip(s), is recommended. A false profile view is considered in cases of hip dysplasia. When the surgeon is faced with cases of severe hip dysplasia, and when considering the use of customized components, we recommend obtaining a preoperative CT scan with thin (1-mm) cuts.[rx]

On imaging, the hip joint is assessed for joint space narrowing, the presence of osteophytes, and the presence of subchondral sclerosis and/or degenerative cysts. Particular attention is paid to the planned center of hip rotation (COR) in relation to the native COR. The surgeon should also have an idea of planned cup medialization and corresponding reaming required to ensure appropriate medialization of the acetabular implant. Finally, any appreciable LLD can also be calculated utilizing any combination of described methods.

The Technique of Total Hip Arthroplasty

Procedural steps

After the surgical approach is completed, the next step required prior to visualizing the acetabulum is the femoral neck osteotomy. This is most commonly with a reciprocating saw beginning at a starting point about 1-cm to 2-cm proximal to the lesser trochanter. This is continued in a proximal-lateral direction toward the base of the greater trochanter.  Once the neck osteotomy is completed, the femoral head and neck are freed of all soft tissue attachments and removed.

Acetabular visualization is accomplished with a combination of retractors. Some surgeons prefer the anterior retractor placement at the 2 o’clock (right hip) or 10 o’clock (left hip) position, in addition to bent Hohmann retractors at the 12’ o-clock (both hips) and 8’ o-clock (right hip) or 4’ o-clock (left hip) positions. A blunt Hohmann (or “No. 3”) retractor is placed in the extra-capsular position at the level of the trans-acetabular ligament (TAL). The ligamentum teres/fibrofatty pulvinar remnants are excised to expose the acetabular teardrop, followed by removal of the labrum (if present) to ensure efficient use of the acetabular reamers.

Preferred reaming methods consist of starting small (i.e., size 44) and focusing on appropriate medialization of the cup with exposure of the medial wall without protruding. Once medialization is achieved, sequential reaming in the planned position of the press-fit implanted cup becomes the major focus. Most commonly, this is in the 35 to 40 degrees of inclination and 15 to 20 degrees of anteversion range. Once all sclerotic bone is reamed and a healthy bleeding bony bed is established, the acetabular component is inserted in press-fit fashion followed by insertion of the corresponding liner.

The femur is then prepared with a ream and/or broach system-specific instrumentation. This is continued until provisional press-fit stability is achieved. Then with the trial femoral stem in place, the hip should be reduced and evaluated for stability utilizing a combination of standard or increasing neck offset trial implants. The head can also be adjusted based on the specific system used. Most implants offer a variety of “plus” and “minus” head size options to add or subtract additional length based on trial total hip stability.

One method for intraoperative THA stability parameters includes the following:

• A shuck test is utilized to free any potential interposed soft tissue and to also evaluate stability with axial traction
• Equal leg lengths: The patella and heels are compared to the contralateral extremity via direct palpation
• With the hip at zero degrees of extension, the hip is externally rotated, and avoidance of posterior impingement is ensured
• The hip should be ranged in abduction and external rotation to ensure avoidance of posterior impingement and anterior subluxation
• The hip should be brought to 90 degrees of flexion with additional adduction and internal rotation to about 70 to 90 degrees and remain stable

Direct lateral (Hardinge)

This approach, also known as the trangluteal approach, does not use a true inner nervous plane. Superficial dissection splits the fascia lata to reach the gluteus medius. The superior gluteal nerve enters the gluteal medius muscle belly at approximately 3-5 cm proximal to the greater trochanter. Proximal dissection may result in nerve injury, leading to postoperative Trendelenburg gait, characterized by compensatory movements to address hip abductor weakness. The transgluteal approach has been cited as having the lowest dislocation rate at 0.55%, compared to 3.23% for the posterior approach and 2.18% for the anterolateral approach [rx].

Wound Closure

Attention to detail is required, and a methodical closure is unanimously advocated. A nonabsorbable, braided, sterile, surgical suture composed of ethylene terephthalate suture is used to repair the capsule and/or short external rotators to the proximal femur via two trans-osseous tunnels. One protocol includes the use of a unidirectional or bi-directional barbed suture for the deep fascial, deep fat, and deep dermal/subcutaneous layers. Staples or monocryl can be used for the skin. Some surgeons prefer using a running barbed monocrystal-based suture augmented by a mesh dressing and skin glue closure. A sterile dressing is then applied and left in place without being changed for the first seven days. An abduction pillow placed and patient education about the appropriate hip flexion precautions and activity restrictions in the early postoperative period is important. Topical tranexamic acid (TXA) application prior to pulsatile saline lavage and commencement of the closure is also recommended.

Pharmacologic modalities for DVT prophylaxis

Although the most effective agent for prophylaxis against DVT and venous thromboembolic events (VTE) remains debated, many surgeons have started using aspirin which has been demonstrated suitable efficacy and equivalent outcomes with respect prophylaxis against symptomatic PE in select groups of total joint patients [rx] compared to other agents such as low molecular weight heparin (LMWH) [rx].

Postoperative pain management

Medication

If pain is severe and intolerable following medicine may be considered to prescribe to control pain and postoperative healing.

• Antibiotic – Cefuroxime or Azithromycin, or  Flucloxacillin or any other cephalosporin/quinolone antibiotic must be used to prevent infection or clotted blood remove to prevent furthers swelling and edema.
• NSAIDs – Prescription-strength drugs that reduce both pain and inflammation. Pain medicines and anti-inflammatory drugs help to relieve pain and stiffness, allowing for increased mobility and exercise. There are many common over-the-counter medicines called non-steroidal anti-inflammatory drugs (NSAIDs). They include and Ketorolac, Aceclofenac, Naproxen, Etoricoxib.
• Corticosteroids – Also known as oral steroids, these medications reduce inflammation.
• Muscle Relaxants –  These medications provide relief from associated muscle spasms.
• Neuropathic Agents – Drugs(pregabalin & gabapentin) that address neuropathic—or nerve-related—pain. This includes burning, numbness, and tingling.
• Opioids – Also known as narcotics, these medications are intense pain relievers that should only be used under a doctor’s careful supervision.
• Topical Medications – These prescription-strength creams, gels, ointments, patches, and sprays help relieve pain and inflammation through the skin.
• Calcium & vitamin D3 – to improve bone health and healing fracture. As a general rule, men and women age 50 and older should consume 1,200 milligrams of calcium a day, and 600 international units of vitamin D a day.
• Dietary supplement-to remove general weakness & improved health.
• Antidepressants – A drug that blocks pain messages from your brain and boosts the effects of endorphins (your body’s natural painkillers).
• Glucosamine & Diacerein, Chondroitin sulfate – can be used to tightening the loose tension, cartilage, ligament, and cartilage, ligament regenerates cartilage or inhabit the further degeneration of cartilage, ligament. They are structural components of articular cartilage, and the thought is that a supplement will aid in the health of articular cartilage. No strong evidence exists that these supplements are beneficial in knee OA; in fact, there is strong evidence against the use according to the AAOS guidelines. There are no major downsides to taking the supplement. If the patient understands the evidence behind these supplements and is willing to try the supplement, it is a relatively safe option. Any benefit gained from supplementation is likely due to a placebo effect.
• Vitamin C – It essential to healing fracture and soft tissue infection.

Complications of Total Hip Arthroplasty

The following are some major complications following THA.

THA Dislocation

About 70% of THA dislocations occur within the first month following index surgery. The overall incidence is about 1% to 3%. Risk factors include: [rx]

• Prior to hip surgery (a most significant independent risk factor for dislocation)
• Elderly age (older than 70 years)
• Component malpositioning: Excessive anteversion results in anterior dislocation and excessive retroversion results in posterior dislocation
• Neuromuscular conditions/disorders (for example, Parkinson disease)
• Drug/alcohol abuse[rx][rx]

Recurrent THA dislocations often result in revision THA surgery with component revision.

The surgical approach is also associated with the risk of dislocation. Masonis and Bourne [rx] found that the direct lateral approach had the lowest dislocation rate at 0.55%, compared to 3.23% for the posterior approach. Kwon et al. [rx] similarly found the lowest rate of dislocation with a direct lateral approach (0.43%) compared to anterolateral (0.7%) and posterior approach with soft tissue repair (1.01%).

THA Periprosthetic Fracture 

THA periprosthetic fractures (PPFs) are increasing in incidence with the overall increased incidence of procedures in younger patient populations.

Intraoperative fractures can occur and involve either the acetabulum and/or femur. Acetabular fractures occur in 0.4% of press-fit acetabular implant components, most often during component impaction. Risk factors include under reaming more than 2 mm, poor patient bone quality, and dysplastic conditions. Intraoperative femur fractures occur in up to 5% of primary THA cases as reported in some series. Risk factors include technical errors, press-fit implants, poor patient bone quality, and revision surgery.[rx]

Treatment of fractures surrounding the femoral stem is reliably managed using the Vancouver classification system.

THA Aseptic Loosening

As in its counterpart TKA procedure, aseptic loosening is the result of a confluence of steps involving particulate debris formation, prosthesis micromotion, and macrophage activated osteolysis. Treatment requires serial imaging and radiographs and/or CT imaging for preoperative planning. Persistent pain requires revision THA surgery.[rx]

Wound Complications

The THA postoperative wound complication spectrum ranges from superficial surgical infections (SSIs) such as cellulitis, superficial dehiscence, and/or delayed wound healing, to deep infections resulting in full-thickness necrosis. Deep infections result in returns to the operating room for irrigation, debridement (incision and drainage) and depending on the timing of the infection, may require explant of THA components.

THA Prosthetic Joint Infection (PJI)

The incidence of prosthetic total hip infection (THA PJI) following primary THA is approximately 1% to 2% as reported in the literature.  Risk factors include patient-specific lifestyle factors (morbid obesity, smoking, intravenous [IV] drug use and abuse, alcohol abuse, and poor oral hygiene). Other risk factors include patients with a past medical history consisting of uncontrolled diabetes, chronic renal and/or liver disease, malnutrition, and HIV (CD4 counts less than 400).[rx]

The most common offending bacterial organisms in the acute setting include Staphylococcus aureus, Staphylococcus epidermidis, and in chronic THA PJI cases, coagulase-negative Staphylococcus bacteria.  Treatment in the acute setting (less than 3 weeks after index surgery) can be limited to I and D, polyethylene exchange, and retention of components. This is commonly referred to as the “I and D, head/liner exchange” treatment modality. In addition, IV antibiotics are utilized for up to 4 to 6 weeks duration. Outcomes vary and are often influenced by multiple intraoperative, patient-related factors, and offending bacterial organism, but studies site a 55% successful outcome rate.

More aggressive treatments, especially in the setting of presentation beyond the acute (3- to 4-week time mark) includes a 1 or 2-stage revision THA procedure with interval antibiotic spacer placement. The surgeon must ensure and document evidence of infection eradication.

Venous thromboembolism events (VTE)

Pulmonary embolism (PE) and deep vein thrombosis (DVT), together referred to as venous thromboembolism (VTE), comprise the most dreaded complications following THA[rx].  The median incidence on in-hospital VTE events during the index admission following THA is approximately 0.6%, increasing to up to 2.5% in total joint revision surgeries[rx].

Other Complications and Considerations

Other potential THA complications include the following:

• Sciatic nerve palsy
• Leg Length Discrepancy (LLD)
• Iliopsoas impingement
• Heterotopic ossification
• Vascular injury

Material and Methods of Total Hip Arthroplasty

References