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This review summarizes the sclerotic zone's pathophysiology, characterization, formation process, and impact on femoral head necrosis.

The sclerotic zone is a reaction interface formed during the repair of femoral head necrosis.

Compared with normal bone tissue, the mechanical properties of the sclerotic zone are significantly enhanced.

Many factors influence the formation of the sclerotic zone, including mechanics, bone metabolism, angiogenesis, and other biological processes.

The sclerotic zone plays an essential role in preventing the collapse of the femoral head and can predict the risk of the collapse of the femoral head.

Regulating the formation of the sclerotic zone of the femoral head has become a direction worthy of study in treating femoral head necrosis.

There is no universal safe zone for cup orientation. Patients with spinal arthrodesis or a degenerative lumbar spine are at increased risk of dislocation.

The relative contributions of the hip (femur and acetabulum) and of the spine (lumbar spine) in body motion must be considered together. The pelvis links the two and influences both acetabular orientation (i.e. hip flexion/extension) and sagittal balance/lumbar lordosis (i.e. spine flexion/extension).

Examination of the spino-pelvic motion can be done through clinical examination and standard radiographs or stereographic imaging. A single, lateral, standing spinopelvic radiograph would be able to providemost relevant information required for screening and pre-operative planning.

A significant variability in static and dynamic spinopelvic characteristics exists amongst healthy volunteers without known spinal or hip pathology.

The stiff, arthritic, hip leads to greater changes in pelvic tilt (changes are almost doubled), with associated obligatory change in lumbar lordosis to maintain upright posture (lumbar lordosis is reduced to counterbalance for the reduction in sacral slope). Following total hip arthroplasty and restoration of hip flexion, spinopelvic characteristics tend to change/normalize (to age-matched healthy volunteers).

The static spinopelvic parameters that are directly associated with increased risk of dislocation are lumbo-pelvic mismatch (pelvic incidence – lumbar lordosis angle >10°), high pelvic tilt (>19°), and low sacral slope when standing. A high combined sagittal index (CSI) when standing (>245°) is associated with increased risk of anterior instability, whilst low CSI when standing (<205°) is associated with increased risk of posterior instability.

Aiming to achieve an optimum CSI when standing within 205–245° (with narrower target for those with spinal disease) whilst ensuring the coronal targets of cup orientation targets are achieved (inclination/version of 40/20 ±10°) is our preferred method.

Offsets in the frontal plane are important for hip function.

Research on total hip arthroplasty (THA) surgery agrees that increasing femoral offset up to 5 mm could improve functional outcome measures.

The literature indicates that global offset is a key parameter that physicians should restore within 5 mm during surgery and avoid decreasing.

Substantiated findings on acetabular offset are lacking despite its recognized importance, and the medialization approach must be assessed in light of its shortcomings.

Future research, possibly through improved measurement, unified definitions, patient-specific surgical planning, and technology-enhanced surgical control, with specific focus on acetabular offset, is needed to better understand its impact on THA outcomes.

Total hip arthroplasty (THA) is a remarkably successful operation that has grown rapidly its utilization.

Early modern THA constructs as developed by Sir John Charnley featured cemented femoral stems and acetabular components. The technique of cementing components for THA has evolved over time.

Modern acetabular preparation requires exposure of the subchondral bone with appropriate cement penetration into the trabecular bone, whereas femoral preparation requires cleaning of the canal, cement restrictor placement, retrograde filling, and pressurization of the cement.

When used appropriately, these techniques result in excellent long-term survivorship of implants and are also widely considered to be the ideal method of fixation for hip fractures.

The purpose of this article to review the history, properties, techniques, and outcomes of bone cement utilization in THA.

Hip joints with bearings composed of cobalt–chromium alloy (metal-on-metal bearings) have been one of the most widely used implants in joint replacement arthroplasty. Unfortunately, these implants can contribute to a complication called aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL), a type IV metal hypersensitivity response around the joint.

Consistent with such bearings, increased metal debris can be found in the surrounding fluids and in remote tissues and organs, due to wear and corrosion. It is hypothesized that metal ions released from the prosthesis (including Co²⁺) can potentially form haptens with proteins such as serum albumin in synovial fluid that in turn elicit ALVAL.

Generally, elevated cobalt and chromium levels in synovial fluids may indicate implant failure. However, such measurements cannot be used as a reliable tool to predict the onset of ALVAL. To detect ALVAL, some diagnostic tests, questionnaires and imaging techniques have been used clinically with some success, but a standardized approach is lacking.

At present, guidelines for implant usage and patient management are ambiguous and inconsistent across health care authorities. To reduce and better manage the development of ALVAL, further research into the precise molecular mechanism(s) by which ALVAL develops is urgently needed.

Identification of diagnostic and prognostic biomarkers for ALVAL is required, as are more standardized guidelines for surgery and patient management.

Bone morphology has been increasingly recognized as a significant variable in the evaluation of non-arthritic hip pain in young adults.

Increased availability and use of multidetector CT in this patient population has contributed to better characterization of the osseous structures compared to traditional radiographs.

Femoral and acetabular version, sites of impingement, acetabular coverage, femoral head–neck morphology, and other structural abnormalities are increasingly identified with the use of CT scan.

In this review, a standard CT imaging technique and protocol is discussed, along with a systematic approach for evaluating pelvic CT imaging in patients with non-arthritic hip pain.

There is currently a debate on whether all Vancouver B2 periprosthetic hip fractures should be revised.

The aim of our work was to establish a decision-making algorithm that helps to decide whether open reduction and internal fixation (ORIF) or revision arthroplasty (RA) should be performed in these patients.

Relative indications in favour of ORIF are low-medium functional demand (Parker mobility score (PMS) <5), high anaesthetic risk (American Society of Anesthesiologists score (ASA) ≥ 3), many comorbidities (Charlson Comorbidity Index (CCI) ≥ 5), 1 zone fractured (VB2.1), anatomical reconstruction possible, and no prior loosening (hip pain).

Relative indications in favour of RA are high functional demand (PMS ≥6), low anaesthetic risk (ASA< 3), few comorbidities (CCI<5), fracture ≥ 2 zones (VB2.2), comminuted fractures, and prior loosening (hip pain).

In cemented stems, those fractures with fully intact cement–bone interface, no stem subsidence into the cementraliser, cement mantle anatomically reducible, and some partial stem-cement attachment can be safely treated with ORIF.