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Trochanteric Osteotomies

Key Points Contemporary uses include difficult exposure and soft tissue tensioning. Multiple techniques are available; use a method that achieves surgical goals, allows the greatest chance of healing, and is easiest for surgeon and patient. Locking plate technology may allow for a higher union rate, but painful hardware remains an issue. Obtain stable, reliable fixation. Avoid full weight-bearing and active abduction until healing is achieved. Avoid…

Posterior Approaches to the Hip

Key Points The posterior approach to the hip allows excellent exposure of the femur and acetabulum for total hip arthroplasty. The extensile nature of the posterior approach makes it an important tool for primary and revision surgery. Minimally invasive surgery has yet to show any clinical advantage over standard posterior approaches to the hip. The posterior approach to the hip preserves the hip abductor mechanism. Posterior…

Anterolateral Approach for Primary Total Hip Replacement

Key Points The anterolateral approach to the hip retains the posterior capsule and external rotators, which may enhance hip stability. The anterolateral approach reduces hip dislocation compared with the posterior approach. Patients at higher risk for postoperative dislocation—such as those with spasticity, high range of motion, small socket sizes, abductor deficiencies, and compliance issues such as alcohol abuse—may benefit from an anterolateral approach. Repair of the…

Direct Anterior Approach With Special Table for Primary Total Hip Arthroplasty

Key Points The direct anterior approach (DAA) is the only intermuscular, internervous approach to the hip. A specialized orthopedic table enables facile exposure of the femur for implantation. Early functional recovery may be gained by patients with the DAA. Care must be taken to avoid common complications associated with this approach. The anterior approach was first described by Smith-Petersen in 1917 and was modified by Heuter,…

Direct Anterior Approach Without a Special Table for Primary Total Hip Arthroplasty

Key Points The direct anterior approach (DAA) provides a safe approach to the hip joint with the advantages of using both an internerve and intermuscular plane and avoiding abductor muscle disruption. It allows for early patient mobilization and fast recovery. The approach can be extended both proximally and distally using special techniques. Using the supine position on a conventional table allows for a faster and less…

Exposures of the Acetabulum

Key Points The ilioinguinal approach allows access to visualize the entire anterior column of the acetabulum, as well as palpable access to portions of the posterior column. The Stoppa approach can be used for exposure of the anterior pelvic ring and in conjunction with the lateral window of the ilioinguinal approach for exposure of the acetabular region. The Kocher-Langenbeck approach allows direct visualization of the dorsocranial…

Anatomy of the Hip

Key Points The acetabulum is deepened by the labrum, a fibrocartilaginous rim that becomes the transverse acetabular ligament inferiorly as it bridges the cotyloid notch. The transverse acetabular ligament may be used as an intraoperative landmark for acetabular component positioning during total hip arthroplasty. The gluteus medius is a fan-shaped muscle that arises from both the lateral surface of the ilium and the undersurface of the…

Normal Hip Embryology and Development

Key Points Lower limb development occurs in utero in its entirety during the fetal stage of development. The primordium of the hip joint is an amorphous cartilage model in which the two sides of the joint are indistinct until the autolytic process at the interzone creates a “joint space” during the seventh week postconception. Developmental dysplasia occurs when the intimate fit between the developing femoral head…

Bone Grafts in Hip Surgery

Key Points Autologous bone graft is osteogenic, osteoinductive, and osteoconductive, with complete histocompatibility and no risk of infectious disease transmission. It is considered the gold standard for bone graft and is the most favored graft material in musculoskeletal reconstruction. Advantages of bone allograft use include availability of materials and avoidance of donor site morbidity associated with autograft harvesting. Disadvantages of bone allograft use include lack of…

Biologic Responses to Metal Debris and Metal Ions

Key Points Tissue reactions can be to the products of metal wear, modular junction tribocorrosion, or both; the characteristics of the debris can vary between these different sources. Long-term systemic effects of large amounts of metallic debris rarely involve cardiomyopathy and sensory neuropathy; autopsy retrieval studies suggest that the quantities of debris associated with typical amounts of metal wear or corrosion products are generally well tolerated…

Biologic Responses to Particle Debris

Key Points Periprosthetic osteolysis is an adverse biologic reaction due to wear particles from joint replacements. Other contributory factors include increased intraarticular pressure and contamination of particles with bacterial or cellular by-products. Excessive wear particle production stimulates a nonspecific chronic inflammatory reaction that results in increased bone degradation and decreased bone formation. Interactions among many cell types are important to the development of osteolytic reactions. Macrophages…

Acetabular Component Fixation

Key Points Fixation of acetabular components in total hip arthroplasty (THA) spans three phases: a transient, primary phase of fixation achieved in the operating room; an intermediate phase, which occurs only with cementless implants, in which new bone heals around the implant component; and a tertiary phase of secondary fixation in which the interface between implant and bone (cementless) or cement and bone (cemented) remodels as…

Materials in Hip Surgery: Ceramics

Key Points Ceramics currently used in total hip arthroplasty (THA) include alumina, zirconia-toughened alumina, and oxidized zirconium. Ceramic implant success is dependent on manufacturing ceramic with high density, high purity, and small grains. Zirconia-toughened alumina has smaller grain size, higher fracture toughness, and better wear resistance than earlier generations of pure alumina ceramic. Wear resistance of ceramics can be attributed to the extreme smoothness and high…

Materials in Hip Surgery: Ultra-High-Molecular-Weight Polyethylene

Key Points Ultra-high-molecular-weight polyethylene (UHMWPE) remains the polymer bearing material of choice for hard-on-soft joint replacement bearing couples. Historical UHMWPE formulations were subject to high wear and oxidation-induced embrittlement, resulting in osteolysis and component delamination. Major improvements in wear and oxidative stability have been achieved through deliberate chemical modifications—primarily, cross-linking and management of free radicals—with concomitant reductions in osteolysis. Cross-linking improves wear resistance but at the…

Materials in Hip Surgery: Polymethylmethacrylate

Key Points Bone cement (polymethylmethacrylate [PMMA]) does not act as a glue to fix implants to bone. Rather, it serves as a grout to fill space with fixation achieved by mechanical interlock. The ability to shape, form, and infiltrate PMMA as needed during surgery is an appealing aspect of the material. Long-term fixation and survival can be achieved with PMMA-cemented implant systems. Shrinkage of the cement…

Tribology of the Artificial Hip

Key Points Wear of the bearing surface is a major factor in the service life of total hip and surface replacements. The hip bearing constitutes a tribological system; thus, wear is a system property impacted by multiple variables, such as bearing dimensions, anatomic placement, bearing materials, loading conditions, joint motion, and lubricant. Various bearing couples with different wear properties are available. A cobalt-chromium-molybdenum (Co-Cr-Mo) and ceramic…

Biomechanics of the Artificial Hip Joint

Key Points Muscle forces play an integral role in the loading environment of the hip. If the mechanical role of major muscles is neglected in biomechanical analyses, joint contact forces tend to be underestimated, the tensile and compressive strains in the femur are often overestimated, and torsional effects are mostly underestimated. Restoring the hip center to its anatomic location, specifically mediolaterally, is essential for minimizing the…

Biomechanics of the Natural Hip Joint

Key Points The physiologic range of motion (ROM) of the hip is affected by many morphologic and soft tissue factors that are not well understood. Clearly, systemic factors, such as age and joint degeneration, impair motion. However, ethnicity, sex, and culture are also important, as remodeling changes occur over time to accommodate activities of daily living (ADLs). The acetabular labrum plays a vital role in the…

Spinal navigation, robotic surgery, and three-dimensional printing

Spinal navigation 1 Briefly outline the development of spinal navigation. Spinal navigation was introduced in the early 1990s as advances in computer-based technologies enabled a transition from frame-based systems developed for cranial surgery to frameless navigation systems. First-generation frameless systems involved a range of technologies, including two-dimensional (2D) fluoroscopy and wired navigation instruments. Second-generation systems involved passive reflective reference frames, point-by-point matching (PPM), self-registration, and relied…

Ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis

1 What is ankylosing spondylitis? Ankylosing spondylitis (AS) is a seronegative inflammatory rheumatic disease that affects the sacroiliac joints, spine, and peripheral joints. Eponyms for AS include Marie-Strümpell disease and von Bechterew disease. AS is a subtype of a group of interrelated disorders termed seronegative spondyloarthritides , which includes AS, psoriatic arthritis, reactive arthritis, and arthritis in association with ulcerative colitis or Crohn disease. These conditions…