This study aims to evaluate the clinical, radiographic, and perioperative outcomes of short femoral stems implanted during primary total hip arthroplasty performed through a minimally invasive direct anterior approach (DAA). Short femoral stems have been developed to preserve proximal femoral bone stock, potentially provide a more physiological load transfer, and facilitate implantation through less invasive surgical exposures, particularly in younger and more active patients.

The stem is a cementless hydroxyapatite-coated triple-tapered short stem, has been previously used because its design allows simplified femoral canal preparation and easier implant insertion during minimally invasive anterior approaches, where femoral exposure may be technically demanding. However, previous reports have shown conflicting results regarding implant survivorship and radiographic outcomes, including increased rates of radiolucent lines, pedestal formation, and stem subsidence, particularly among younger and more active patients.

The present study will investigate the technical and clinical implications of using short femoral stems through a minimally invasive anterior approach. Primary outcomes will include perioperative complication rates, wound characteristics, peri-incisional tissue condition, postoperative bleeding, and other surgery-related complications. Secondary outcomes will include postoperative pain, functional recovery, clinical outcome scores, implant survivorship, and serial radiographic findings at short- and mid-term follow-up.

Given the limited evidence currently available regarding the short- and mid-term performance of short femoral stems implanted through the direct anterior approach, this study aims to provide a comprehensive clinical and radiographic evaluation of these implants over time. Adverse events will be continuously monitored through scheduled clinical and radiographic assessments.

Inclusion Criteria:

• Diagnosis of primary hip osteoarthritis or osteonecrosis
• Minimally invasive direct anterior approach
• Cementless femoral component
• Minimum follow-up of 2 years
• Patient willingness to participate in the study with written informed consent
• Age over 18 years
• Male or female patients

Exclusion Criteria:

• Other diagnoses of secondary hip osteoarthritis
• Non-anterior surgical approach
• Cemented or other types of components
• Patient unwillingness to participate in the study
• Inadequate clinical and radiological documentation

The study population includes consecutively treated adult patients undergoing primary total hip arthroplasty performed through a direct anterior approach with a cementless femoral component, at the Department of Orthopaedics, Trauma Surgery, and Hip and Knee Arthroplasty and Revision Surgery of the IRCCS Istituto Ortopedico Rizzoli. Patients will be included from 2022 (retrospective cohort) to 2027 (prospective cohort).