Hip degeneration presents clinically on a spectrum from mild pain to incapacitating disability. End-degenerative joint disease of the hip is best managed with total hip arthroplasty (THA), which has demonstrated overall excellent long-term outcomes. It is important to review recent advances in preoperative evaluation, intraoperative execution, and postoperative complications of THA.
Osteoarthritis is the most common disease of the joints, afflicting an estimated 303 million people worldwide. Although any joint can be affected, the hip and knee are the most commonly involved joints. Years lived with disability and the prevalence and incidence of hip and knee osteoarthritis have increased 8% to 10% since 1990.1
These increased rates are mirrored by increases in US health care expenditures, as discussed in a 2020 study that found that spending for osteoarthritis accounted for $80 billion annually.2
The disability from hip osteoarthritis involves pain that affects individuals’ quality of life and activities of daily living but has other far-reaching consequences. Work absences, sleep disturbances, sexual dysfunction, and increased risk of cardiovascular disease are additional effects of symptomatic osteoarthritis.3
Hip osteoarthritis generally presents with pain, primarily in the groin or thigh, and stiffness that becomes more noticeable with activities such as walking, navigating stairs, and putting on socks and shoes. As the osteoarthritis worsens, so too does hip range of motion, particularly in internal and external rotation with hip flexion contractures common in the later stages of disease. Radiographs demonstrate joint-space narrowing, subchondral sclerosis, osteophyte formation, and subchondral cysts (Figure 1
). The treatment of hip osteoarthritis with mild or moderate symptoms involves oral or topical anti-inflammatory medications, activity modification, the use of a cane in the contralateral hand,4
weight loss, and physical therapy for managing
pain and to improve function. Intra-articular steroid injections can also improve function and reduce short-term pain for patients with symptomatic osteoarthritis.5
The mainstay of treatment for severe hip osteoarthritis is THA.
Figure 1 Standing AP radiograph of the pelvis from a patient with severe left hip osteoarthritis. Joint-space narrowing, subchondral sclerosis, osteophyte formation, and subchondral cysts are present.
Secondary arthritis of the hip can occur because of a number of conditions, most commonly inflammatory arthritis (including rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and systemic lupus erythematosus), posttraumatic arthritis, and osteonecrosis.
Inflammatory arthritis is known to cause significant deformities of the hip such as coxa profunda and protrusio acetabuli (also known as arthrokatadysis), rapidly destructive bony erosion, and severe hip ankylosis/autofusion. Advances in the pharmacologic management of inflammatory arthritis using disease-modifying antirheumatic drugs and biologic agents have dramatically improved the systemic symptoms of these patients and reduced the amount of severe orthopaedic deformities seen currently. Patients with inflammatory arthritis who undergo THA are at higher risk of periprosthetic joint infection (PJI) because of immunocompromise from antirheumatic medications and the disease itself. A consensus guideline published by the American College of Rheumatology and the American Association of Hip and Knee Surgeons has outlined specific recommendations on perioperative medication management.6
Most nonbiologic medications can be continued perioperatively; however, biologic agents should be stopped one cycle before surgery and restarted after surgery once the wound is sufficiently healed.
Posttraumatic arthritis of the hip results from chondral damage due to a significant prior injury to the hip. Intra-articular fractures of the femoral head or acetabulum cause direct cartilage damage and articular surface incongruity. Expedient and anatomic restoration of intra-articular surfaces via open reduction and internal fixation is key to diminish the risk of posttraumatic arthritis. Traumatic hip dislocation can also cause chondral damage as well as disruption of the blood supply to the femoral head, leading to osteonecrosis. Other severe musculoskeletal injuries may also predispose patients to the development of posttraumatic hip arthritis due to joint contractures, an altered gait pattern, and abnormal hip biomechanics leading to increased joint reactive forces.
Osteonecrosis of the hip is a condition caused by compromised blood supply to the femoral head secondary to a number of medical conditions including sickle cell disease, HIV, alcoholism, high-dose steroid usage, radiation treatment, and hypercoagulable states, as well as prior hip trauma. Plain radiographs and MRI are useful for diagnosis and classification (Ficat and Arlet, Steinberg). Surgical management should be considered for patients with precollapse osteonecrosis and intractable pain as well as those who have definitive femoral head collapse. Core decompression, with or without bone grafting, may be indicated in early stage osteonecrosis without femoral head collapse. More extensive procedures such as proximal femoral osteotomy or vascularized free fibula transfer are also used, but like all of these hip salvage procedures, they have mixed results and may affect the ultimate outcome of subsequent arthroplasty. THA is indicated for patients with end-stage femoral head collapse and has excellent outcomes.
Total Hip Arthroplasty
Medical Optimization/Risk Stratification
Of the many recent advances in the surgical evaluation and management of degenerative joint disease of the hip, preoperative patient optimization has the potential to be the most effective. Recognizing which patients to operate on and when is of paramount importance in avoiding dangerous medical complications from surgery. The most commonly cited risk factors for complications after THA are smoking, body mass index
less than 35 to 40 kg/m2
and greater than 20 kg/m2
, albumin greater than 3.5 g/dL, narcotic/ethanol dependence, hemoglobin A1c less than 8%, hemoglobin greater than 10 g/dL, and preoperative nasal colonization with Staphylococcus aureus
Identification and optimization of these modifiable risk factors can enhance early recovery with documented lower lengths of hospital stay and increased rates of home discharge. Additional beneficial outcomes of medical optimization before THA include decreased readmission rates, postoperative emergency department visits, PJI rates, and mortality.6
Some nonmodifiable risk factors have been linked to poorer outcomes after surgery. In a 2019 study, the authors assessed demographic and comorbidity variables and found that the American Society of Anesthesiologists physical classification system score greater than 3 was a significant risk factor for 30-day medical complications, surgical complications, readmission, revision surgery, and mortality rates following primary total joint arthroplasty (TJA). Peripheral vascular disease was the most significant risk factor for medical complications and revision surgery, whereas bleeding disorders were the most significant risk factor for readmission and overall mortality.8
Preoperative optimization has been shown to significantly increase the workload burden on surgeons and other providers. A survey of members of the American Association of Hip and Knee Surgeons published in 2020 reported that 153 additional minutes were spent on preoperative medical optimization work not accounted for in Current Procedural Terminology or hospital billing codes. Additionally, 87% of respondents reported a significant increase in preoperative workload for THA since 2013.9
The Centers for Medicare & Medicaid Services announced in late 2019 that THA would be removed from the inpatient-only procedure list as of January 1, 2020.10
As outpatient THA becomes more prevalent, careful medical optimization and risk stratification is mandatory to help select which patients and medical comorbidities may be appropriate for surgery outside the inpatient setting. Multiple risk assessment tools have been developed in an effort to stratify patients into high-risk and low-risk categories for readmission after outpatient surgery. Scoring systems such as the outpatient arthroplasty risk assessment and the American Society of Anesthesiologists score have been shown to identify which patients can most safely undergo outpatient TJA.11
Other reports, however, have refuted the requirement of a formal scoring assessment tool. Some specific comorbidities have been found to be associated with an increased risk of overnight observation rather than same-day discharge, even after medical optimization. Coronary artery disease, chronic obstructive pulmonary disease, and benign prostatic hypertrophy/urinary frequency have been shown to carry the highest risk of overnight stay after THA. The overall most commonly cited reasons for an unexpected overnight stay are urinary retention, postoperative nausea and vomiting, hypotension, pain management, hypoxia, and patient convenience.12
Surgical approach has been a heavily debated topic in THA over the past 10 years, with the premise that direction of approach would affect surgical outcomes. Considering the ubiquitous push for outpatient and short-stay THA, an optimal surgical approach would facilitate a decrease in length of hospital stay, enhanced rehabilitation, and optimizing early recovery. In addition, decreasing resource utilization in the form of postoperative physical therapy and nursing has the potential to lower overall cost and decrease health care expenditures.
Recent studies suggest that different approaches carry different complication profiles, rather than different long-term outcomes.13
The anterior approach was highly marketed and rejuvenated in the early 2000s and was reported in predominantly medium-quality to low-quality studies.14
The findings of meta-analyses and systematic reviews have consistently demonstrated improved early outcomes in the first 6 weeks postoperatively for the anterior approach compared with the posterior or lateral approaches.14
Despite the improved early outcomes, other studies have demonstrated a higher complication rate with the anterior approach, particularly revision surgeries and PJIs, with no difference in dislocation rates compared with the posterior approach.16
Extent of tissue damage, rather than direction of approach, has been proposed as a more important proxy of level of invasiveness in THA and has been difficult to study in controlled settings. Tissue sparing approaches, in addition to the anterior and mini-posterior approaches, include the superior capsulotomy/direct superior approach or other modifications of more extensile approaches, such as the percutaneously assisted total hip. These approaches to THA have been reported as safe with excellent short-term outcomes, although long-term and direct comparison investigations are warranted.17
Ultimately, factors such as pain management, patient selection, surgeon experience, and hospital perioperative resource utilization may prove to be more important than surgical approach.
Table 1 Trends in Bearing Surface Utilization for Total Hip Arthroplasty in Young Patients From 2006 to 2016
Ceramic on ceramic
Metal on metal
Ceramic on polyethylene
Metal on polyethylene
Data from Hart CM, Chen C, Hsiue PP, et al: National trends in total hip arthroplasty bearing surface usage in extremely young patients between 2006 and 2016. Arthroplast Today 2021;10:51-56.
Despite the overwhelming successes of THA, the optimal bearing surface has yet to be established. As implant survivorship improves and patient expectations escalate, THA has been performed more frequently in younger, more active patients. It was once thought that young patients would benefit from hard-on-hard bearing surfaces (ceramic-on-ceramic, or metal-on-metal [MoM]) to improve durability and obviate polyethylene wear-induced osteolysis and subsequent prosthetic loosening. MoM utilization peaked in 2008 but soon dramatically decreased as failure reports were published. Failures of MoM surface bearings were widely demonstrated because of metal wear debris inducing adverse local tissue reactions (ALTRs). Additionally, excellent in vivo and in vitro performance of modern, highly cross-linked polyethylene18
contributed to the decline of hard-on-hard bearing usage. One recent database study demonstrated a drastic increase in ceramic-on-polyethylene bearings in association with a significant decrease in MoM utilization from 2006 to 201618
). These changes in bearing utilization have been mirrored by older age groups with a shift from hard-on-hard to hard-on-soft bearings with a strong predominance for ceramic on polyethylene as the most common bearing surface.19
Dual-mobility articulations have seen widespread adoption in the United States in primary and revision THA for patients at high risk of instability. These constructs have been shown to improve hip stability because of larger head size and subsequent increased jump distance rather than increased range of motion to impingement.20
Dual-mobility bearings have been shown to have lower dislocation rates in primary and revision THA and lower revision because of instability, with no difference in overall all-cause revision rate for primary THA compared with standard bearing surfaces.21
It is important, however, to distinguish modularity (or lack thereof) and specific materials among different dual-mobility bearings because these have implications for wear, stability, and mechanical complications. A 2020 study reported on the use of dual mobility in the American Joint Replacement Registry from 2012 to 2018. It was found that marked dual-mobility usage increased from 6.7% in 2012 to 12% in 2018, with a particular increase in revision THA from 19.5% in 2012 to 30.6% in 2019. Specific factors associated with higher dual-mobility utilization were younger patient age, female sex, and major teaching and small hospitals, as well as Western state geography.22
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