Lower limb malrotation significantly influences hip biomechanics and contributes to the pathogenesis of femoroacetabular impingement (FAI), labral injury, and degenerative joint disease. This chapter explores the multifaceted impact of rotational abnormalities—including femoral and tibial torsion, as well as acetabular version—on hip function, stability, and impingement patterns. We highlight how deviations in femoral version, whether increased (anteversion) or decreased (retroversion), alter the range of motion and predispose patients to specific labral injury patterns. Increased femoral anteversion is associated with anterior instability and intrasubstance labral tears, while retroversion correlates with labral hypertrophy and superior partial tears, especially in the presence of cam-type morphology. Clinical assessment of malrotation involves gait analysis, rotational profile testing, and impingement and instability manoeuvres. Radiographic evaluation includes pelvic AP and Dunn views, long-leg alignment films, and low-dose CT rotational profile assessment (CT-RPA), which provides a comprehensive view of femoral and tibial torsion. MRI and diagnostic injections further aid in distinguishing intra- from extra-articular sources of pain. Femoral torsion is measured via CT—there are several methodologies, with no consensus on which best reflects clinical range of motion. Acetabular version is assessed at cranial, central, and caudal levels. Pelvic tilt affects functional acetabular version. Tibial torsion, defined by the angular relationship between the posterior condylar axis and the malleolar axis, also plays a critical role in lower limb alignment and patellar tracking. Surgical management of malrotation includes periacetabular osteotomy (PAO) to improve lateral and anterior femoral head coverage, anteverting periacetabular osteotomy (aPAO) for acetabular retroversion, proximal femoral osteotomy (PFO) or distal femoral osteotomy (DFO) for femoral version correction, and tibial osteotomies for torsional abnormalities. The choice of technique depends on pre-existing limb alignment, surgeon expertise, and the anatomical site of deformity. Patellar instability, often linked to excessive external tibial torsion and increased femoral version, may be addressed through medial patellofemoral ligament (MPFL) reconstruction or tibial tubercle osteotomy (TTO). This chapter also explores the complexity of combined version abnormalities, particularly those quantified by the McKibbin index, which assesses the interplay between femoral and acetabular version. High indices suggest anterior instability, while low indices exacerbate impingement. Surgical correction must consider compensatory mechanisms between femoral and tibial torsion, as addressing one deformity may unmask another. Multidisciplinary team (MDT) involvement is crucial for optimal outcomes, especially in patients with concurrent hip and knee symptoms. Shared decision-making ensures that treatment strategies align with patient expectations, functional goals, and biomechanical realities. Future research should focus on refining diagnostic accuracy, understanding compensatory torsional relationships, and developing evidence-based frameworks for surgical sequencing. Emerging technologies such as machine learning, and navigated surgery, may enhance patient selection and personalise correction strategies.