Does Transhumeral Osseointegration After Amputation Improve Patient-reported Outcomes and Prosthesis Use?

Abstract

Background: Individuals who have undergone transhumeral amputation often have difficulty wearing conventional socket-based prostheses, leading to frequent dissatisfaction and abandonment of the prosthesis. Osseointegration surgery may alleviate or mitigate many of these issues by providing a firm, reliable attachment between the humerus and the prosthesis, potentially leading to better functionality and quality of life; however, it is unclear whether the risks inherent to transdermal bone-anchored implants outweigh the potential functional benefits.

Questions/purposes: (1) Were there improvements in patient-reported outcome measures at 2 years among patients with transhumeral amputations undergoing osseointegration compared with presurgical function in those patients? (2) What was the frequency and severity of complications related to the osseointegration procedures?

Methods: Between October 2016 and April 2021, we recruited 12 active duty service members, retirees, and healthcare beneficiaries to undergo transhumeral osseointegration surgery using the Osseointegrated Prostheses for the Rehabilitation of Amputees (OPRA) implant system in this prospective, observational study. The primary indication was difficulty wearing a traditional socket-based prosthesis after extended efforts to do so and a residual humerus of ≥ 10 cm, while the exclusion criteria were a residual humerus of<≤ 10 cm, BMI > 35 kg/m2, severe peripheral vascular disease including diabetes, taking immunosuppressant medications, pregnancy, and those unable to sign their own consent. A total of 24 people were screened, and 12 met the inclusion criteria. All 12 participants (all men with a mean ± SD age of 38 ± 12 years) completed the minimum follow-up time of 2 years for this analysis. The majority of the patients' mechanism of injury was blast (10 of 12) followed by motor vehicle collision (2 of 12). All 12 participants in this prospective FDA early feasibility study underwent both Stage 1 (fixture implantation into the humerus) and Stage 2 (muscle and skin fashioning) surgery, and none was lost to follow-up at a minimum of 2 years after April 2021. Participants were asked to complete the DASH questionnaire, the Defense and Veterans Pain Rating Scale (DVPRS), and items from three domains of the Patient-Reported Outcomes Measurement Information System (PROMIS) before surgery and at 3, 6, 12, and 24 months after the second stage of the procedure. They also reported their prosthetic use time in hours in a day and days in a week. We recorded the frequency of complications related to the procedure, including soft tissue, mechanical, and infectious complications.

Results: Participants had improvements in mean ± SD DASH scores between baseline (36 ± 23) and a minimum of 2-year follow-up (19 ± 13) (mean difference 17 [95% confidence interval (CI) 1 to 33]; p = 0.04), and they had increases in days per week of prosthetic use time between baseline (4 ± 3) and the 2-year follow-up (7 ± 1) (mean difference 3 [95% CI 1 to 5]; p = 0.02). We found no difference in the physical function score (p = 0.47), pain interference score (p = 0.46), pain behavior score (p = 0.16), the DVPRS (p = 0.58), or prosthetic use time in hours per day (p = 0.09). We found no superficial soft tissue infections, but we did observe two soft tissue complications, two mechanical complications, and one skin penetration aperture complication consisting of marginal necrosis that healed uneventfully. No patients who developed these complications returned to the operating room.

Conclusion: This FDA early feasibility study found notable improvements in patients' DASH scores and prosthetic use, suggesting that transhumeral osseointegration using the OPRA implant system is a promising approach for patients who have lost a limb. Complications were relatively minor and treatable, and no infections were seen, which is consistent with prior evidence that infections may be considerably less frequent for those living with transhumeral amputation than for those who have undergone osseointegration for lower extremity amputations. As such, the technique appears to be promising in this patient population, with the caveat that this is a preliminary study in a very small selected patient population. These data can be used to justify the use of the OPRA implant system in appropriate patients living with transhumeral amputations, help inform future clinical trial design, as well as to support a Premarket Approval application with the FDA.

Level of evidence: Level II, therapeutic study.