Computer Navigation in Hip Arthroplasty and Robotics

Key Points Precision of component placement and biomechanical reconstruction of total hip arthroplasty (THA) is one of THA's weak links. Successful THA depends on proper positioning of components. Computer navigation helps achieve an accurate cup position and reduces human error, especially by incorporating pelvic tilt into the anteversion number. Biomechanical reconstruction—particularly hip length, offset, and center of rotation (COR)—can be quantified with navigation. Navigation has demonstrated…

Ceramic-on-Ceramic Bearings

Key Points Ceramic-on-ceramic bearings in total hip arthroplasty were first implemented as a solution to wear debris and subsequent osteolysis seen in traditional bearing surfaces. Ceramics are hard, scratch resistant, wear resistant, low friction, thermodynamically stable, chemically inert, biocompatible, and resistant to corrosion. Concerns about ceramics include risk of fracture, the phenomenon of stripe wear, motion-related noise, impingement, limitations in component options, and increased cost relative…

Highly Cross-Linked Polyethylene Bearings

Key Points Highly cross-linked polyethylene (HCLPE) has demonstrated wear rate reduction of between 40% and 95% over conventional polyethylene. Current evidence in the literature does not reveal significant rates of osteolysis or autoimmune reaction to HCLPE. Long-term studies have not demonstrated significant adverse events with HCLPE and would support its continued use. Questions still remain about the long-term significance of reactive oxygen species formation during the…

Uncemented Short Metaphyseal Femoral Components

Key Points Metaphyseal fit and ingrowth can provide both rotational and axial stability without distal diaphyseal support. Bone remodeling after insertion of metaphyseal engaging short stems shows endosteal condensation and cortical hypertrophy in the proximal metaphyseal region of the femur. Functional Harris Hip Scores and Western Ontario and McMaster Universities Osteoarthritis Index pain scores are equivalent in patients with metaphyseal engaging short stems and uncemented stems…

Uncemented Tapered Femoral Components With Single/Double/Rounded Tapered Implants

Key Points Single-taper stems are tapered in the medial/lateral (ML) plane but are flat in the anteroposterior (AP) plane, appearing as a rectangle on a lateral radiograph. Double-taper stems maintain the ML taper design but taper in the AP plane as well. Tapered round stems expand on prior stem designs by maintaining a geometric taper in both the ML and AP planes and adding an increased…

Uncemented Tapered Femoral Components With Blade-Shaped Parallel-Sided Implants

Key Points Uncemented tapered femoral components have shown predictable and durable results in primary total hip arthroplasty. There are subtle differences in the inherent design of and surgical technique recommended for the various tapered cementless stems available in the current market. These implants appear to have in large part addressed the incidence of complications associated with other cementless femoral component design (thigh pain, stress shielding, and…

Uncemented Extensively Porous-Coated Femoral Components

Key Points Uncemented extensively porous-coated femoral components have a 98% stem survival rate at 20 years. The implant can be used for all diagnoses and in all qualities of bone. Defining characteristics of the stem include its nontapered cylindrical distal geometry with extensive porous coating. The surgical technique is a reamed technique. The goal of the surgical technique is to obtain 5 cm of diaphyseal scratch fit.…

Cemented Femoral Components

Key Points Indication: cemented stems ( Fig. 65.1 ) are indicated in patients in all age groups who require a hip arthroplasty for any pathology ( Fig. 65.2 ). Results from national joint registries confirm that cemented taper-slip femoral components yield predictable excellent results in the hands of surgeons of all levels of experience. Restoration of biomechanics: the use of collarless polished tapered stems confers significant…

Uncemented Acetabular Components

Key Points Requirements for cementless ingrowth include initial implant stability, appropriate pore size, adequate surface contact with host bone, and an implant material that is conducive to bone ingrowth. Titanium has been shown to be qualitatively and quantitatively superior to cobalt-chromium as an ingrowth material. Several studies at more than 20 years’ follow-up show durable long-term fixation with titanium, hemispheric, cementless acetabular components inserted with screws.…

Cemented Acetabular Components

Key Points Cemented total hip replacement (THR) continues to be a commonly performed technique in arthroplasty. The cemented acetabular component is often considered the “weak link” in the longevity of a fully cemented THR. Each patient should undergo assessment and plain radiographic examination to ensure accurate templating and planning of the operation. Best practice in performing the technique of cementing the component is described. Limitations of…

Resurfacing Hip Arthroplasty: Evolution, Design, Indications, Techniques, and Results

Key Points The success of the first generation of resurfacing implants was limited by inferior manufacturing processes and materials that were the best available at the time. Improvements in the understanding of tribology; improvements in materials, design, and surgical technique; and insight of clinicians has led to the evolution of contemporary resurfacing designs that in many cases have limited the early failure mechanisms previously seen. The…

Preoperative Planning and Templating for Primary Hip Arthroplasty

Key Points Patient selection: Total hip arthroplasty (THA) should be reserved for patients with severe hip pathology who have failed a comprehensive nonoperative treatment program and who are capable, both physically and cognitively, of recovering from the surgery. In addition to assessment of the patient's overall health status, several key historical features should be ascertained, including quality, severity, and location of pain; impact on activities; prior…

Rating Systems and Outcomes of Total Hip Arthroplasty

Key Points The outcome of total hip arthroplasty (THA) is generally excellent, resulting in long-lasting improvement in pain and function for the vast majority of patients. The profound improvement in pain and function associated with THA results in a large standard effect size that introduces a paradox of outcomes assessment in that patients find it subjectively difficult to interpret subtle differences in outcomes associated with the…

Technique Spotlight: ORIF vs. Extension Block Pinning vs. Dynamic External Fixation for Proximal Interphalangeal Joint Dislocations

Introduction This chapter will highlight three available techniques to achieve a stable proximal interphalangeal (PIP) joint after dislocation and fracture-dislocations: extension block pinning, open reduction internal fixation (ORIF) including hemihamate arthroplasty, and dynamic external fixation. Many other treatment options exist. Treatment should be tailored to the injury pattern and patient demographics. Extension Block Pinning Indications Extension block pinning may be done when a PIP joint dorsal…

Proximal Interphalangeal Joint Dislocations

Introduction Proximal interphalangeal (PIP) joint injuries are common and in spite of seemingly minor injuries, these can affect the overall hand function. Stiffness is common with these injuries and there is often permanent residual swelling, changing the size of the digit. Patients often present in a delayed manner as it was assumed to be a “jammed finger” that would get better. When it does not improve…

Technique Spotlight: Phalanx Fractures—Pins vs. Screws vs. Plates—When and How

Diaphyseal Fractures of the Proximal and Middle Phalanx Closed Reduction Percutaneous Pinning The majority of proximal phalanx fractures displace with apex volar angulation. Therefore closed reduction involves traction with simultaneous flexion at the metacarpophalangeal (MP) joint to 70–90 degrees and extension at the proximal interphalangeal (PIP) joint. This maneuver relaxes the intrinsic muscles, which flex the proximal fragment, and permits the extensor hood to aid the…

Phalanx Fractures

Introduction Fractures of the phalanges are common injuries, with reported rates of 340,000 per year. The majority occur following an accidental fall followed closely by injuries sustained after being struck by an object or person. While these are common injuries across all ages and demographics, there is a higher incidence in children and adolescents. They are commonly managed nonoperatively however, surgery plays an important role in…

Metacarpophalangeal Joint Dislocations

Introduction Dislocations of the metacarpophalangeal (MCP) joint of the hand are caused by trauma to the hand, typically from a fall, with forced hyperextension of the joint. Athletes may more frequently sustain these injuries particularly in contact sports or ball-handling sports that require diving, setting, or catching balls at very high speeds. This chapter will focus on dislocations resulting in isolated soft tissue damage. Joint dislocations…

Technique Spotlight: Volar vs. Dorsal Approaches for Metacarpophalangeal Joint Dislocations

Indications Metacarpal fractures are one of the most commonly sustained hand fractures and the overwhelming majority of these fractures may be treated nonoperatively with or without immobilization. Surgical intervention is frequently considered when the fracture leads to a functionally limiting or aesthetically displeasing deformity. In general, intra-articular displacement, malrotation, fracture shortening of ≥5 mm, and angulation that can cause compensatory posturing or extensor lag are not…

Metacarpal Fractures—Pins vs. Plates vs. Intramedullary Devices—When and How

Indications for Surgical Treatment Metacarpal fractures can be treated nonoperatively or operatively depending on the fracture characteristics of angulation, displacement, rotation, and stability following reduction when applicable. The osseous and soft tissue anatomy of the metacarpals provides functional stability to many of the fractures that occur and contributes to the success of nonoperative treatment. Absolute surgical indications include open fractures, open metacarpophalangeal (MP) or carpometacarpal (CMC)…