November | December 2017 42 Bone-anchored percutaneous (through the skin) implants have been available for the rehabilitation of patients with amputation outside of the United States for nearly 30 years. However, the U.S. Food and Drug Administration (FDA) has recently approved the use of one osseo-anchored device, and others are under various stages of development. In this article, we seek to provide a current status update on the field of osseointegration for patients and prosthetic professionals alike. The OPRA System The Osseointegrated Prosthesis for the Rehabilitation of Amputees (OPRA™) was initially developed in Sweden by the late Per-Ingvar Brånemark, widely credited as being the founder of the field of osseointegration and the father of modern dental implantology. His titanium fixtures were adapted for craniomaxillofacial (skull and jaw structure) and other reconstructive applications, including bone-anchored hearing aids (BAHA). In 1990, the first OPRA devices were placed in a young Swedish woman with high bilateral above-knee amputations due to trauma. Despite undergoing routine revision surgery, she continues to walk without the use of a socket 27 years later. In 1999, OPRA patients were entered into a prospective study under the direction of Dr. Rickard Brånemark. Over an eight-year period, a total of 51 consecutive patients with 55 transfemoral (above-knee) amputations were enrolled. The cumulative two-year implant survival was 92 percent. Validated outcome measures showed statistically significant improvements in prosthetic use, mobility, global situation, and fewer problems. The most common problem was superficial infection (54.9 percent), treated with oral antibiotics. Three implants were removed for aseptic (sterile) loosening, and one for deep infection. 1 On July 16, 2015, the OPRA System (Integrum AB, Mölndal, Sweden) was approved by the FDA for Humanitarian Device Exemption (HDE) usage in patients with above- knee amputations due to trauma or cancer and who have rehabilitation problems with or cannot use a conventional socket prosthesis. The effectiveness of this device for this use has not been demonstrated. To date, the OPRA System (Figures 1-4) has been used in nine above- knee amputation patients at the University of California, San Francisco (UCSF) as part of a prospective Institutional Review Board (IRB)-approved study. In order to qualify for the study, patients must be above-knee amputees with problems using a conventional socket prosthesis. Patients must be skeletally mature and weigh less than 100 kg (220 pounds). Exclusion criteria include severe peripheral vascular disease, diabetes mellitus, skin Current Status Update: Technology Figure 1. Illustration of osseo-anchored fixture and percutaneous abutment (support for prosthesis) after Stage 2 surgery. Figure 2. Radiograph of fixture and abutment. Figure 3. Clinical photo of above-knee patient. Figure 4. Schematic design of implant, connector and external prosthesis.