Osseointegration (OI) is the direct anchorage of a metal implant into bone, allowing for the connection of an external prosthesis to the skeleton. Osseointegration was first discovered in the 1960s based on the microscopic analysis of titanium implant placed into host bone. New bone was observed to attach directly to the metal surface. Following clinical investigations into dentistry applications, OI was adapted to treat extremity amputations. These bone anchored implants, which penetrate the skin and soft tissues, eliminate many of the challenges of conventional prosthetic sockets, such as poor fit and suspension, skin breakdown, and pain. Osseointegrated implants show promise to improve prosthesis use, pain, and function for amputees. The successful process of transcutaneous metal integration into host bone requires three synergistic systems: the host bone, the metal implant, and the skin‐implant interface. All three systems must be optimized for successful incorporation and longevity of the implant. Osseointegration begins during surgical implantation of the metal components through a complex interplay of cellular mechanisms. While implants can vary in design—including the original screw, press fit implants, and compressive osseointegration—they face common challenges to successful integration and maintenance of fixation within the host bone. Overcoming these challenges requires the understanding of the complex interactions between each element of OI. This review outlines (a) the basic components of OI, (b) the science behind both the bone‐implant and the skin‐implant interfaces, (c) the current challenges of OI, and (d) future opportunities within the field.

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Objective: To compare the outcomes of elderly patients with nondisplaced and minimally displaced femoral neck fractures treated with internal fixation versus arthroplasty. Data Sources: A comprehensive search of the MEDLINE, Embase, and central databases was conducted through June 25, 2019. Study Selection: Studies were included if the sample population was (1) 60 years of age or older, (2) had nondisplaced or minimally displaced (Garden I or II) femoral neck fractures, and (3) if the study compared internal fixation versus arthroplasty. Only full-text English manuscripts were included. The primary outcome was reoperation. Secondary outcomes included mortality, patient-reported outcomes, length of hospital stay, infection, and blood transfusions. Data Extraction: Two authors independently extracted data from the included studies. Each study was independently evaluated for quality using the Cochrane risk of bias assessment. Data Synthesis: Of the 1597 identified articles, 4 manuscripts met the eligibility criteria with a total of 579 patients (236 treated with hemiarthroplasty and 343 treated with internal fixation). Patients treated with arthroplasty had a significantly lower risk of reoperation when compared with those treated with internal fixation [relative risk: 0.30 (95% CI, 0.16–0.55, P < 0.01)]. There was no significant difference detected in 1-year mortality risk between the 2 treatment groups. Conclusions: In elderly patients with nondisplaced and minimally displaced femoral neck fractures, treatment with hemiarthroplasty may reduce the relative risk of reoperation by 70% when compared with internal fixation. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.