Safety and Performance of Bone-Anchored Prostheses in Persons with a Transfemoral Amputation: A 5-Year Follow-up Study

Surgical technique of minor revision of a transcutaneous osseointegration prosthetic system (TOPS) with implant retention

OBJECTIVE

Transcutaneous osseointegration prosthetic systems (TOPS) offer a stable skeletal attachment for artificial limbs post-extremity amputation, serving as an alternative to socket attachment. Press-fit osseointegration implants (OI) utilized in TOPS consistently enhance quality of life and mobility for amputees, particularly those experiencing socket-related issues. Despite notable benefits, late complications such as infection and implant loosening pose challenges unique to TOPS due to their percutaneous nature. Recent studies indicate a low risk of implant failure but highlight the prevalence of minor soft tissue complications. Successful TOPS implementation is hypothesized to rely on early osseointegration and effective drainage of fluid discharge from the stoma. Factors influencing implant survival encompass implant characteristics, bone quality, and host factors. Longitudinal follow-up data reveal changes in periprosthetic bone and soft tissue conditions over time, necessitating ongoing clinical management. Distal bone resorption, evidenced by X‑ray, may result from stress shielding or local osteitis, leading to stoma-related complaints and jeopardizing implant survival. Understanding these dynamics is crucial for optimizing TOPS outcomes and addressing evolving patient needs.

INDICATIONS

Purulent and bloody discharge from the stoma with pain and radiographic evidence of distal cortical resorption.

CONTRAINDICATIONS

Complaints attributed to other pathologies, signs of progressive bone resorption or implant loosening.

SURGICAL TECHNIQUE

We propose a unique innovative surgical approach to address symptomatic distal bone resorption in individuals undergoing treatment with press-fit transcutaneous osseointegration prosthetic systems (TOPS) following limb amputation. Distal bone resorption can lead to painful symptoms and compromise the effectiveness of TOPS, necessitating a stepwise intervention strategy. The protocol involves assessing cortical involvement through radiographs, followed by surgical debridement with assessment of potential implant loosening. The next step involves application of a two-part mirror-polished sleeve to mitigate local soft-tissue irritation and promote physiological drainage. Patient education is paramount, emphasizing the potential for limited pain relief and the risk of postoperative infectious complications. This protocol offers a structured approach to managing distal bone resorption in TOPS recipients, aiming to optimize treatment outcomes while ensuring informed patient consent.

POSTOPERATIVE MANAGEMENT

Following surgery, the cement used to fixate the sleeve must harden and after 24 h the leg prosthesis can be clicked on again. With regard to the surgical wound, no special measures are necessary other than standard orthopedic postoperative wound care. In view of this revision surgical procedure, we recommend to continue antibiotics for 6 weeks with preference for clindamycin 3 × 600 mg/day.

RESULTS

Limited preliminary clinical data show promising results.

Safety and performance of contemporary press-fit titanium osseointegration implants in lower extremity amputation : a five-year follow-up study

Aims

Treatment using bone-anchored prostheses (BAPs) with press-fit femoral osseointegration implants (OIs) has been used in patients with lower limb amputations for more than two decades. The development of these OIs has enabled treatment in patients with a short transfemoral and a transtibial amputation. The aim of this follow-up study was to report the safety of this treatment at five years postoperatively, the prosthesis wearing time (PWT), and health-related quality of life (HRQoL).

Methods

All consecutive patients undergoing treatment between March 2015 and June 2018 using one of three different OIs were eligible for inclusion. A total of 90 patients were included, of whom 14 were lost to follow-up, leaving 76 available for analysis. The curved- or gamma-osseointegration femoral implant (OFI-C, OFI-Y) was used in patients with a mid-diaphyseal or short transfemoral amputation, respectively. The osseointegration tibial implant (OTI) was used in those with a transtibial amputation. The adverse events which were evaluated included infection (soft-tissue, bone, implant), stoma-related complications, aseptic loosening, implant breakage, periprosthetic fracture, and complications between surgical stages. The functional outcomes which were assessed included the Questionnaire for Persons with a Transfemoral Amputation (Q-TFA)-Prosthetic Use Score (PUS) and the Global Score (GS), for PWT and HRQoL, respectively.

Results

A 94.2% implant survival was achieved at five years (OFI-C = 93.8%, OFI-Y = 93.3%, OTI = 95.5%); five implants were removed. Overall, 27 patients (36%) had a total of 56 infections, 53 (95%) of which were infections of the soft-tissues. Septic loosening occurred in three patients (4%, OFI-C = 2, OTI = 1), resulting in removal of the implant in two. The infection/implant-year ratio was 0.09, 0.16, and 0.24 for OFI-C, OFI-Y and OTI, respectively. Periprosthetic fracture occurred in four patients (5%, all OFI-C); all were treated surgically, three with fixation, one with removal. One patient had asymptomatic radiological evidence of partial aseptic loosening; this was managed conservatively. Stoma-related problems required surgery on 26 occasions, mostly in patients treated with an OFI-Y. The implant was removed in two patients (2.6%) due to unexplained pain. Complications between surgical stages were mostly surgical site infections, requiring bringing forward stage 2 on seven occasions. Baseline Q-TFA-PUS and GS scores increased significantly in all patients, and also when stratified per type of implant with the passage of time.

Conclusion

Contemporary press-fit titanium OIs, when used in lower limb amputations, result in acceptable rates of survival and safety, with considerable improvements in functional outcomes.

Improving quality of life for transfemoral amputees: results from a two-year study of the OPRA implant system and rehabilitation protocol

PURPOSE

Transfemoral amputees face significant functional limitations with traditional socket prostheses. This study evaluates the efficacy and safety of the OPRA (Osseointegrated Prostheses for the Rehabilitation of Amputees) implant system in improving the quality of life for these patients.

METHODS

A retrospective study was conducted on 22 transfemoral amputees (20 male, 2 female; mean age 44.6 years) who underwent OPRA implant surgery between 2019 and 2021. Patients were assessed preoperatively and followed for two years post-surgery. Outcomes were measured using the Questionnaire for Persons with a Transfemoral Amputation (Q-TFA), pain scores, and complication rates.

RESULTS

At two-year follow-up, significant improvements were observed in Q-TFA scores for prosthetic use (30.41 ± 10.90 to 87.68 ± 11.42, p < 0.001), mobility (44.36 ± 15.57 to 71.45 ± 13.72, p < 0.001), problem score (52.40 ± 10.22 to 25.81 ± 9.66, p < 0.001), and global score (43.45 ± 10.87 to 74.95 ± 21.82, p < 0.001). Mean daily prosthesis usage increased from 3.77 ± 2.59 to 13.43 ± 3.76 h (p < 0.001). Complications included minor discharge (67.5%), significant discharge requiring surgical intervention (13.6%), prosthesis removal (9%), and periprosthetic fracture (4.5%).

CONCLUSION

The OPRA implant system significantly improved functional outcomes and quality of life for transfemoral amputees over two years. While complication rates were notable, most were manageable with conservative treatment. These findings suggest that osseointegrated prostheses offer a promising alternative to socket prostheses for suitable candidates, though further research with larger cohorts is warranted to confirm long-term efficacy and safety.

Osseointegration for transfemoral amputees: Influence of femur length and implant sizing on bone-implant contact and alignment

INTRODUCTION

Clinical data on osseointegration (OI) for limb replacement indicates a concerning increase in mechanical complications after five years post-implantation. Since adequate bone-implant contact and proper implant alignment are critical factors for successful osseointegration, it is essential to identify the factors influencing these outcomes. This study aimed to assess the effects of residual femur length and implant sizing on bone-implant contact and implant alignment.

METHODS

Three-dimensional models of eight cadaveric femora were reconstructed from CT scans, and transfemoral amputations were simulated for each femur at three levels: short (ST: 1/3 L), medium (MD: 1/2 L), and long (LG: 2/3 L). Virtual OI surgeries were then performed using computer-aided design (CAD) models, and implant sizes were recorded. Subsequently, the effect of implant sizing was assessed by adjusting the implant size by ±1 mm. Contact length and implant alignment were compared between the groups using repeated measures analysis of variance with Bonferroni correction.

RESULTS

The contact in the ST group (65.2 ± 7.3 %) was significantly less compared to the MD (96.1 ± 4.1 %, p < 0.001) and LG (96.8 ± 3.2 %, p < 0.001) groups. Upsizing increased contact in the ST group by 7.0 ± 2.6 % (p < 0.001), though it did not reach levels comparable to the MD and LG groups (p > 0.05). Additionally, sagittal implant misalignment was larger in the ST group (10.1 ± 2.0°) than in the MD (7.9 ± 1.5°) and LG (3.5 ± 1.6°) groups (p < 0.001), while no difference was observed in coronal implant alignment.

CONCLUSION

These findings highlight the factors influencing mechanical complications of osseointegration implants and provide a basis for refined implant designs and surgical techniques for patients with short residual limbs.

Screening and patient selection for bone-anchored limb implantation and rehabilitation: what makes a good candidate?

Osseointegration of a bone-anchored limb (BAL) is an emerging rehabilitation technique that offers significant advantages over traditional socket prostheses. By addressing functional limitations and recurrent cutaneous complications, BAL systems have shown an 82%-90% increase in daily prosthesis use among patients, who also report improvements in functional ability, balance, comfort, and overall quality of life. Despite these benefits, the process of patient selection for BAL remains underdeveloped, with evidence-based guidelines still in their infancy. This article aims to propose a workflow for patient selection and screening in BAL osseointegration, leveraging the current literature, interdisciplinary clinical experience, and established models. A comprehensive evaluation process is suggested that incorporates anatomical, physiological, psychological, and lifestyle factors. These include radiological evaluation, amputation history, prosthetic component assessment, laboratory tests, psychiatric history, cognitive assessments, and considerations of home safety and postoperative care. The evaluation should ideally be conducted by an interdisciplinary team to ensure a balanced consideration of risks and benefits for each candidate. As the understanding of BAL osseointegration advances, it is expected that patient indications will expand and contraindications will be more clearly defined. The proposed workflow aims to standardize patient selection, thereby optimizing surgical outcomes and rehabilitation processes. This approach is essential for maximizing the benefits of BAL systems while ensuring patient safety and improving long-term rehabilitation outcomes.

Improved primary stability and load transfer of a customized osseointegrated transfemoral prosthesis compared to a commercial one

BACKGROUND

Transfemoral osseointegrated prostheses, like other uncemented prostheses experience the risk of aseptic loosening and post-operative periprosthetic fractures, with an incidence between 3% and 30%. To date, however, osseointegrated off-the-shelf prostheses are manufactured in a limited number of sizes, and some patients do not meet the strict eligibility criteria of commercial devices. A customized osseointegrated stem was developed and a pre-clinical in vitro investigation of the stem was performed, to evaluate its biomechanical performance.

MATERIALS AND METHODS

Six human cadaveric femurs were implanted with commercial stems, while the six contralateral were implanted with customized stems. Three more femurs that did not meet the eligibility criteria for the commercial stems were implanted with the customized stems. Two different loading scenarios (compression-flexion, and torsion) were simulated to measure the primary implant stability and the load transfer. For both loading scenarios, the displacements of the implant with respect to the host bone, and the strains on the bone surface were measured using digital image correlation (DIC). To measure the pull-out force, a tensile force was applied to the prostheses.

RESULTS

The translational inducible micromotions during the compression-flexion test of the OsteoCustom stem were more than 4 times smaller than the commercial one (p < 0.05). The rotational inducible micromotions of the OsteoCustom stem were more than 3 times smaller than the commercial one (p < 0.05). Similar results were found from the torsional test. The full-field strain distribution of the commercial stem showed a slightly higher strain concentration near the stem tip (maximum principal strain = 1928±127 µɛ) than the OsteoCustom (maximum principal strain = 1758±130 µɛ). Similar results were found for the femurs that did not meet the eligibility criteria for the commercial stems and could be implanted with the OsteoCustom. No statistically significant difference was found in the extraction force between the two groups.

DISCUSSION AND CONCLUSION

These results support the hypothesis that the OsteoCustom stem can offer better primary stability and load distribution compared to commercial implants. The outcome highlighted the potential benefits of the OsteoCustom prosthesis, which is capable of including a wider range of femoral anatomies than the current standard.

How To Improve Patient Selection in Individuals With Lower Extremity Amputation Using a Bone-anchored Prosthesis

BACKGROUND

Many patients with a lower limb socket-suspended prothesis experience socket-related problems, such as pain, chronic skin conditions, and mechanical problems, and as a result, health-related quality of life (HRQoL) is often negatively affected. A bone-anchored prosthesis can overcome these problems and improve HRQoL, but these prostheses have potential downsides as well. A valid and reliable tool to assess potential candidates for surgery concerning a favorable risk-benefit ratio between potential complications related to bone-anchored prostheses and improvements in HRQoL is not available yet. Having this information may inform treating physicians and patients when deciding whether to pursue bone-anchored prostheses.

QUESTIONS/PURPOSE

In this study, we asked: (1) What is the difference in HRQoL at 6, 12, and 24 months among patients who underwent lower limb bone-anchored prosthesis treatment after using a socket-suspended prosthesis preoperatively? (2) What factors are associated with change in HRQoL 24 months after lower limb bone-anchored prosthesis treatment? (3) Which complications occurred within 24 months after lower limb bone-anchored prosthesis treatment? (4) What factors are associated with minor to severe complications within 24 months after lower limb bone-anchored prosthesis treatment?

METHODS

A total of 206 patients who underwent lower limb bone-anchored prosthesis treatment (femoral or tibial) at the Radboud University Medical Center between May 2014 and September 2020 were included in this study. Of those, 8% (17 of 206) were lost to follow-up at 24 months without meeting a study endpoint (not attending the clinic unrelated to the bone-anchored prosthesis, re-amputation), and another < 1% (1 of 206) died prior to 24 months, leaving 92% (189 of 206) of the original group who had a follow-up time of at least 24 months. The mean ± SD age was 54.3 ± 12.7 years, and 72% were men. Amputation levels included 64% (139 of 218) transfemoral amputation, 3% (7 of 218) knee exarticulation, 32% (70 of 218) transtibial amputation, 0.5% (1 of 218) foot amputation, and 0.5% (1 of 218) osseointegration implant after primary amputation. Causes of amputation included 52% (108 of 206) trauma, 8% (17 of 206) oncology, 19% (38 of 206) dysvascular, 12% (25 of 206) infection, 1% (2 of 206) congenital, and 8% (16 of 206) other. Primary outcomes were generic HRQoL (Short-Form 36 health survey mental component summary [MCS] and physical component summary [PCS] scores), disease-specific HRQoL (Questionnaire for Persons with a Transfemoral Amputation global score), and complication occurrence (infection, implant complications such as loosening or breakage, stoma-related problems, periprosthetic fracture, and death). Multivariable multiple regression was used to develop association models. These models demonstrated which group of characteristics were associated with change in HRQoL at 24 months of follow-up and occurrence of complications within 24 months of follow-up. Assessments were carried out at baseline (preoperative while using a socket-suspended prosthesis) and after 6, 12, and 24 months of bone-anchored prosthesis use.

RESULTS

Generic HRQoL PCS score improved 25% (β 9 [95% confidence interval (CI) 7 to 11]) at 6 months and maintained that improvement at the 12-month (β 9 [95% CI 7 to 11]) and 24-month (β 8 [95% CI 7 to 10]) follow-up visit compared with baseline (p < 0.001). The generic HRQoL MCS score did not change compared with baseline. Disease-specific HRQoL improved 77% (β 30 [95% CI 25 to 34]), 85% (β 33 [95% CI 28 to 37]), and 72% (β 28 [95% CI 24 to 33]) at 6-month, 12-month, and 24-month follow-up, respectively, compared with baseline (p < 0.001). Patients with the following group of characteristics were more likely to experience a better physical generic HRQoL at 24 months of follow-up: younger patients with a lower physical generic HRQoL, and a traumatic cause of amputation combined with a lower activity level. Patients with the following group of characteristics were more likely to experience a better disease-specific HRQoL at 24 months of follow-up: dysvascular cause of amputation, lower prosthetic comfort combined with a lower activity level, and lower prosthetic comfort combined with a lower or higher activity level. In addition, patients with an average mobility level were more likely to experience less improvement in disease-specific HRQoL at 24 months of follow-up. Infections were the most common complications in the total cohort (116 events in 206 patients), of which the majority consisted of soft tissue infections (98% [114 of 116]). Bone infection did not occur. Septic implant loosening occurred in 1% (2 of 214) of total implants (3% [2 of 66] of tibial implants), both treated with transfemoral amputation. Younger and higher functioning patients had the lowest risk of minor complications within 24 months of follow-up. Women, older patients, patients with a lower activity level, and older patients with more time since amputation had the highest risk of minor complications within 24 months of follow-up. Patients with a higher disease-specific HRQoL had the highest risk of moderate or severe complications within 24 months of follow-up.

CONCLUSION

In agreement with earlier research, this study confirmed that generic HRQoL and disease-specific HRQoL improved after bone-anchored prosthesis use. Additionally, this study confirmed that bone-anchored prosthesis has a relatively low likelihood of severe complications but with a high occurrence of minor complications. These were often successfully treated with nonsurgical interventions. Patients who have a favorable risk-benefit ratio between improvements in HRQoL and potential treatment-related complications are most eligible for a bone-anchored prosthesis. These findings may be helpful to patients and treating physicians to aid in patient selection and to inform patients about potential short-term expectations of treatment.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Lower Extremity Osseointegration Postoperative Rehabilitation Protocols: A Scoping Review

OBJECTIVE

Lower-extremity transcutaneous osseointegration is a rehabilitation alternative to socket-suspended prostheses. The rehabilitation process, philosophies, and routines remain under-described. This review, primarily, identifies commonalities and differences among protocols. Secondarily, strategies are proposed to streamline future research of post-osseointegration surgery rehabilitation.

METHODS

Two differently-phrased queries of Google Scholar, Pubmed, Embase, and Web of Science were performed. First using either "osseointegration" or "osseointegrated" or "bone anchored prosthesis" AND [last name]. Second, replacing author name with "physical therapy" or "rehabilitation". Six hundred eighty-eight articles were identified describing lower-extremity rehabilitation following osseointegration. Following software-based deduplication, manual abstract and full-text review, article reference evaluation, and use of Google Scholar's "Cited by" feature, 35 studies were fully analyzed. First, a consolidated summary was made of protocols focusing on stages, timing, and other descriptions of postoperative rehabilitation. Subsequently, strengths and limitations of protocols were considered to propose potential strategies to investigate and optimize postoperative rehabilitation.

RESULTS

All articles describe rehabilitation having this same order of goal progression: from surgery to gradual weight bearing and final goal of independent ambulation. The most impactful difference influencing the stated final goal of independent ambulation was whether one or two surgical stages were performed. No articles reported patient success rate achieving proposed goals and timing, or challenges during rehabilitation. Therefore, the first research suggestion is to investigate actual success rates achieving proposed goals and timing. Second, to further explore rehabilitation of performance deficits, beyond unaided ambulation. Finally, to incorporate technology such as mobility trackers to more objectively understand prosthesis use and mobility.

CONCLUSION

All lower-extremity osseointegration rehabilitation literature recommends identical goal progression order. No studies evaluate patient challenges or variation. Understanding and addressing such challenges may enhance postoperative rehabilitation.

IMPACT

This article consolidates published rehabilitation protocols post-osseointegration surgery. Specific analysis and experimentation of the protocols may enhance the uniformity and potential of patient rehabilitation.

Revision of Press-Fit Bone-Anchored Prosthesis After Implant Failure

Background

The present video article describes the revision of a bone-anchored prosthesis in patients who received an osseointegration implant after transfemoral amputation. Clinical follow-up studies have shown that approximately 5% of all patients who receive press-fit cobalt-chromium alloy femoral implants experience failure of the intramedullary stem component as a result of septic loosening or stem breakage. For stem breakage, stem diameter and the occurrence of infectious events were identified as risk factors. We began regularly utilizing the standard German press-fit endo-exo cast cobalt-chrome implant in 2009, but changed to the forged titanium version in 2014 (BADAL X, OTN Implants) because of the breakages associated with the former implant. No breakages have been reported since making the switch, and as such we currently still utilize the titanium implant. Current Commission Européenne-certified bone-anchored implants for transfemoral amputation include a screw-type stem and a press-fit stem. The revision technique demonstrated in the present article may apply to both types of implant system, but this video is limited to demonstrating the use of a press-fit implant. We describe the 3 stages of debridement, removal, and subsequent implantation of a bone-anchored prosthesis in a revision setting.

Description

We perform this procedure in up to 3 stages, with 10 to 12 weeks between removal of the failed implant and implantation of the revision prosthesis. For stage 1, in case of mechanical failure, the broken remnants of the implant, which may dangle in the soft tissues, are removed. The stoma is debrided, after which spontaneous stoma healing is achieved. In cases of septic loosening, stage 1 includes removal of the implant by retrograde hammering, followed by multiple debridements with flexible reamers and jet lavage until negative cultures are obtained. In stage 2, the broken osseointegration implant is removed with use of a custom-made titanium water-cooled hollow drill. With the use of this drill, we have always been successful in removing the broken implant while maintaining sufficient bone stock for future implant revision. If the corer fails, a larger approach is needed to remove the implant. The corer drill should have a wall that is as thin but as robust as possible in order to avoid cortical perforation, and should be manufactured from a strong material in order to resist the usage against the implant. We utilized a steel corer when initially performing this procedure, which was frequently unsuccessful, necessitating a larger approach to remove the implant. We currently utilize a 3D-printed corer drill with integrated water-cooling system with greater success (Xilloc Medical). This corer is custom-made and needs about 6 weeks for designing and manufacturing. This tool is utilized in the present video article. Stage 3 includes revision implantation of an osseointegration prosthesis, utilizing similar templating as in the primary surgical procedure. The time needed for the bone to recover from explantation is arbitrary, but we allow around 2 to 3 months before implanting a new intramedullary component. In cases of poor bone stock, a bone impaction graft can be applied prior to insertion of revision implant.

Alternatives

A return to the prior mobilization level is an alternative to revision of the failed implant.

Rationale

Failure due to stem breakage can occur in cases utilizing small-diameter cobalt-chromium implants. Such cases can be revised with use of large-diameter titanium implants, provided there is sufficient bone stock. Failure due to septic loosening may occur in patients who are not properly indicated for this procedure, such as those with severe dysvascular disease or diabetes mellitus. A revised implant is also at increased risk for recurrent failure.

Expected Outcomes

Revision of bone-anchored prostheses includes up to 3 stages depending on whether the revision is for septic loosening or stem breakage. Although we allow 10 to 12 weeks before implanting a new intramedullary component, the time needed for the bone to recover from the explantation is arbitrary. During this interval, a temporary socket can be manufactured to allow mobilization with use of an artificial limb; however, most patients use just crutches and/or a wheelchair during this interval.

Important Tips

Be aware of the type of implant that needs to be removed.Prepare for long operative times, especially in cases in which implants need to be cut or when dense cortical bone is expected.Account for 1.5 to 2 mm of extra diameter of the coring drill on either side in order to allow for the curvature of the press-fit implant.Plan for and acquire the right tools. Make sure to have at least 2 corer drills present in case of damage or malfunction.Utilize a fluoroscope frequently during initial drilling around the stem remnant.In case of poor bone stock, prepare for future bone impaction grafting when planning for revision implantation of a bone-anchored prosthesis.

Acronyms and Abbreviations

OI = osseointegration implantBAP = bone-anchored prosthesisBIG = bone impaction grafting.

Advantages of customization of osseointegrated implants in transfemoral amputees: a comparative analysis of surgical planning

BACKGROUND

Commercially available osseointegrated devices for transfemoral amputees are limited in size and thus fail to meet the significant anatomical variability in the femoral medullary canal. This study aimed to develop a customized osseointegrated stem to better accommodate a variety of femoral anatomies in transfemoral amputees than off-the-shelf stems. Customization is expected to enhance cortical bone preservation and increase the stem-bone contact area, which are critical for the long-term stability and success of implants.

METHODS

A customized stem (OsteoCustom) was designed based on the statistical shape variability of the medullary canal. The implantability of the OsteoCustom stem was tested via 70 computed tomography (CT) images of human femurs and compared to that of a commercial device (OFI-C) for two different resection levels. The evaluations included the volume of cortical bone removed and the percentage of stem-bone contact area for both resection levels. Statistical significance was analyzed using paired and unpaired t tests.

RESULTS

The OsteoCustom stem could be virtually implanted in all 70 femurs, while the OFI-C was unsuitable in 19 cases due to insufficient cortical thickness after implantation, further emphasizing its adaptability to varying anatomical conditions. The OsteoCustom stem preserved a greater volume of cortical bone than did the OFI-C. In fact, 42% less bone was removed at the proximal resection level (3.15 cm³ vs. 5.42 cm³, p ≤ 0.0001), and 33% less at the distal resection level (2.25 cm³ vs. 3.39 cm³, p = 0.003). The stem-bone contact area was also greater for the OsteoCustom stem, particularly at the distal resection level, showing a 20% increase in contact area (52.3% vs. 32.2%, p = 0.002) compared to that of the OFI-C.

CONCLUSIONS

The OsteoCustom stem performed better than the commercial stem by preserving more cortical bone and achieving a greater stem-bone contact area, especially at distal resection levels where the shape of the medullary canal exhibits more inter-subject variability. Optimal fit in the distal region is of paramount importance for ensuring the stability of osseointegrated implants. This study highlights the potential benefits of customized osseointegrated stems in accommodating a broader range of femoral anatomies, with enhanced fit in the medullary canal.

Radiological evaluation before and after treatment with an osseointegrated bone-anchor following major limb amputation-a guide for radiologists

Osseointegrated implants have been developed to allow direct skeletal fixation of a prosthesis as an alternative to traditional socket-fitted prostheses for patients who have suffered from a major limb amputation. The implants contribute to improvements in functional outcome and quality of life and radiological evaluation plays a crucial role in pre- and post-operative assessment. This article acts as a guide for radiologists who may be tasked with providing the radiological information required by surgeons and prosthetists. We also look at the radiological appearances of complications that may arise in patients treated with an osseointegrated implant. Plain X-rays are used to screen patients who wish to undergo treatment. Limb-length X-rays are then used to measure the length of any residual bone, and comparisons can be made with the normal side (if present). From this, decisions about the likely size of the implant and the need for further amputation can be made. CT scans enable accurate assessment of the medullary cavity and cortical thickness. Post-operatively, plain X-rays form the mainstay of the routine monitoring of the bone-implant interface. Potential complications include infection, aseptic loosening, mechanical fracture of the implant and periprosthetic fracture. Infection and aseptic loosening can be seen as a lucency at the bone-implant interface which (if left untreated) can lead to loss of the implant. Implant and periprosthetic fractures are radiographically obvious. Radiologists involved in the care of patients undergoing treatment with an osseointegrated implant should become familiar with the imaging requirements so they can contribute to optimal patient outcomes.

Bone-anchored prostheses for transfemoral amputation: a systematic review of outcomes, complications, patient experiences, and cost-effectiveness

Introduction

Bone-anchored prostheses (BAP) are an advanced reconstructive surgical approach for individuals who had transfemoral amputation and are unable to use the conventional socket-suspension systems for their prostheses. Access to this technology has been limited in part due to the lag between the start of a new procedure and the availability of evidence that is required before making decisions about widespread provision. This systematic review presents as a single resource up-to-date information on aspects most relevant to decision makers, i.e., clinical efficacy, safety parameters, patient experiences, and health economic outcomes of this technology.

Methods

A systematic search of the literature was conducted by an information specialist in PubMed, MEDLINE, Embase, CINAHL, Cochrane Library, the Core Collection of Web of Science, CADTH's Grey Matters, and Google Scholar up until May 31, 2023. Peer-reviewed original research articles on the outcomes of clinical effectiveness (health-related quality of life, mobility, and prosthesis usage), complications and adverse events, patient experiences, and health economic outcomes were included. The quality of the studies was assessed using the Oxford Centre for Evidence-Based Medicine Levels of Evidence and ROBINS-I, as appropriate.

Results

Fifty studies met the inclusion criteria, of which 12 were excluded. Thirty-eight studies were finally included in this review, of which 21 reported on clinical outcomes and complications, 9 case series and 1 cohort study focused specifically on complications and adverse events, and 2 and 5 qualitative studies reported on patient experience and health economic assessments, respectively. The most common study design is a single-arm trial (pre-/post-intervention design) with varying lengths of follow-up.

Discussion

The clinical efficacy of this technology is evident in selected populations. Overall, patients reported increased health-related quality of life, mobility, and prosthesis usage post-intervention. The most common complication is a superficial or soft-tissue infection, and more serious complications are rare. Patient-reported experiences have generally been positive. Evidence indicates that bone-anchored implants for prosthesis fixation are cost-effective for those individuals who face significant challenges in using socket-suspension systems, although they may offer no additional advantage to those who are functioning well with their socket-suspended prostheses.

A scoring system to evaluate stability of percutaneous osseointegrated implants for transfemoral amputation with validation in the ITAP clinical trial

Percutaneous osseointegrated implants for individuals with lower limb amputation can increase mobility, reduce socket related pain, and improve quality of life. It would be useful to have an evaluation method to assess the interface between bone and implant. We assessed outpatient radiographs from the Intraosseous Transcutaneous Amputation Prosthesis clinical trial using an interface scoring system which summed and weighted equally measures of implant collar cortical ongrowth and radiolucency along the implant stem/bone interface. Radiographs from 12 participants with unilateral transfemoral amputations (10 males, 2 females, mean age = 43.2, SD = 7.4 years) in the clinical trial from cohort I (implanted in 2008/09) or cohort II (implanted in 2013/14) were collated (mean image span = 7.2, SD = 2.4 years), scale normalised, zoned, and measured in a repeatable way. Interface scores were calculated and then compared to clinical outcomes. Explanted participants received the lowest interface scores. A higher ratio of stem to residuum and shorter residuum's produced better interface scores and there was an association (weak correlation) between participants with thin cortices and the lowest interface scores. A tapered, cemented, non curved stem may provide advantageous fixation while stem alignment did not appear critical. In summary, the interface score successfully demonstrated a non-invasive evaluation of percutaneous osseointegrated implants interfaces when applied to the Intraosseous Transcutaneous Amputation Prosthesis clinical trial. The clinical significance of this work is to identify events leading to aseptic or septic implant removal and contribute to clinical guidelines for monitoring rehabilitation, design and surgical fixation choices.

Infection After Lower-Limb Osseointegration: A Single-Center Retrospective Evaluation of Pathogens, Management, and Outcomes

PURPOSE

Osseointegration (OI) is a novel alternative to traditional socket-suspended prostheses for lower-limb amputees, eliminating the socket-skin interface and allowing for weight bearing directly on the skeletal system. However, the stoma through which the implant attaches to the external prosthesis creates an ingress route for bacteria, and infection rates as high as 66% have been reported. The aims of this study are to classify infection management and long-term outcomes in this patient population to maximize implant salvage.

METHODS

An institutional review board-approved retrospective analysis was performed on all patients who underwent lower-limb OI at our institution between 2017 and 2022. Demographic, operative, and outcome data were collected for all patients. Patients were stratified by the presence and severity of infection. Chi-square and t tests were performed on categorical and continuous data, respectively, using an alpha of 0.05.

RESULTS

One hundred two patients met our study criteria; 62 had transfemoral OI and 40 had transtibial OI. Patients were followed for 23.8 months on average (range, 3.5-63.7). Osteomyelitis was more likely than soft tissue infection to be polymicrobial in nature (71% vs 23%, P < 0.05). Infections at the stoma were mostly (96%) managed with oral antibiotics alone, whereas deeper soft tissue infections also required intravenous antibiotics (75%) or operative washout (19%). Osteomyelitis was managed with intravenous antibiotics and required operative attention; 5 (71%) underwent washout and 2 (29%) underwent explantation. Both implants were replaced an average of 3.5 months after explantation. There was no correlation between history of soft tissue infection and development of osteomyelitis (P > 0.05). The overall implant salvage rate after infection was 96%.

CONCLUSIONS

This study describes our institution's experience managing infection after OI and soft tissue reconstruction. Although infections do occur, they are easily treatable and rarely require operative intervention. Explantation due to infection is rare and can be followed up with reimplantation, reaffirming that OI is a safe and effective treatment modality.

Reliable in vitro method for the evaluation of the primary stability and load transfer of transfemoral prostheses for osseointegrated implantation

Osseointegrated transfemoral prostheses experience aseptic complications with an incidence between 3% and 30%. The main aseptic risks are implant loosening, adverse bone remodeling, and post-operative periprosthetic fractures. Implant loosening can either be due to a lack of initial (primary) stability of the implant, which hinders bone ingrowth and therefore prevents secondary stability, or, in the long-term, to the progressive resorption of the periprosthetic bone. Post-operative periprosthetic fractures are most often caused by stress concentrations. A method to simultaneously evaluate the primary stability and the load transfer is currently missing. Furthermore, the measurement errors are seldom reported in the literature. In this study a method to reliably quantify the bone implant interaction of osseointegrated transfemoral prostheses in terms of primary stability and load transfer was developed, and its precision was quantified. Micromotions between the prosthesis and the host bone and the strains on the cortical bone were measured on five human cadaveric femurs with a typical commercial osseointegrated implant. To detect the primary stability of the implant and the load transfer, cyclic loads were applied, simulating the peak load during gait. Digital Image Correlation was used to measure displacements and bone strains simultaneously throughout the test. Permanent migrations and inducible micromotions were measured (three translations and three rotations), while, on the same specimen, the full-field strain distribution on the bone surface was measured. The repeatability tests showed that the devised method had an intra-specimen variability smaller than 6 μm for the translation, 0.02 degrees for the rotations, and smaller than 60 microstrain for the strain distribution. The inter-specimen variability was larger than the intra-specimen variability due to the natural differences between femurs. Altogether, the measurement uncertainties (intrinsic measurement errors, intra-specimen repeatability and inter-specimen variability) were smaller than critical levels of biomarkers for adverse remodelling and aseptic loosening, thus allowing to discriminate between stable and unstable implants, and to detect critical strain magnitudes in the host bone. In conclusion, this work showed that it is possible to measure the primary stability and the load transfer of an osseointegrated transfemoral prosthesis in a reliable way using a combination of mechanical testing and DIC.

Bone-anchored prostheses for lower limb amputation in a French cohort with 1-15 years of follow-up: implant survival rates, mechanical complications, and reported outcomes

PURPOSE

To evaluate the implant survival rate, mechanical complications, and reported patient outcomes of bone-anchored prostheses for patients with lower limb amputation in France after 1-15 years of follow-up.

METHODS

This retrospective cohort study included patients who underwent surgery at a single center in France between 2007 and 2021. The primary outcomes were the implant survival rate and functional scores assessed by the Questionnaire for Transfemoral Amputees (Q-TFA). Secondary outcomes were adverse events that occurred during follow-up.

RESULTS

The cohort consisted of 20 bone-anchored prostheses in 17 patients. The main level of amputation was transfemoral (82%, n = 14). The main reason for amputation was trauma (n = 15). The mean age at amputation was 32 (range 15-54) years, and the mean age at the first stage of osseointegration was 41 (range 21-58) years. The Kaplan-Meier survival curve showed respective survival rates of 90%, 70%, and 60% at 2, 10, and 15 years. All Q-TFA scores were significantly improved at last the follow-up. Eleven patients (65%) experienced mechanical complications. In total, 37 infectious events occurred in 13 patients (76%), mainly comprising stage 1 infections (68%, n = 25). Only two cases of septic loosening occurred (12%), leading to implant removal.

CONCLUSION

This is the first French cohort of bone-anchored prostheses and among the series with the longest follow-up periods. The findings indicate that bone-anchored prostheses are safe and reliable for amputee patients who have difficulties with classic prostheses.

Transcutaneous Osseointegrated Prosthesis Systems (TOPS) for Rehabilitation After Lower Limb Loss: Surgical Pearls

Background

The biology of osseointegration of any intramedullary implant depends on the design, the press-fit anchoring, and the loading history of the endoprosthesis. In particular, the material and surface of the endoprosthetic stem are designed to stimulate on- and in-growth of bone as the prerequisite for stable and long-lasting integration1-8. Relative movement between a metal stem and the bone wall may stimulate the formation of a connective-tissue interface, thereby increasing the risk of peri-implant infections and implant loss9-12. The maximum achievable press-fit (i.e., the force closure between the implant and bone wall) depends on the diameter and length of the residual bone and thus on the amputation level. Beyond this, the skin-penetrating connector creates specific medical and biological challenges, especially the risk of ascending intramedullary infections. On the one hand, bacterial colonization of the skin-penetrating area (i.e., the stoma) with a gram-positive taxon is obligatory and almost impossible to avoid9,10. On the other hand, a direct structural and functional connection between the osseous tissue and the implant, without intervening connective tissue, has been shown to be a key for infection-free osseointegration11,12.

Description

We present a 2-step implantation process for the standard Endo-Fix Stem (ESKA Orthopaedic Handels) into the residual femur and describe the osseointegration of the prosthesis13. In addition, we demonstrate the single-step implantation of a custom-made short femoral implant and a custom-made humeral BADAL X implant (OTN Implants) in a patient who experienced a high-voltage injury with the loss of both arms and the left thigh. Apart from the standard preparation procedures (e.g., marking the lines for skin incisions, preparation of the distal part of the residual bone), special attention must be paid when performing the operative steps that are crucial for successful osseointegration and utilization of the prosthesis. These include shortening of the residual bone to the desired length, preparation of the intramedullary cavity for hosting of the prosthetic stem, precise trimming of the soft tissue, and wound closure. Finally, we discuss the similarities and differences between the Endo-Fix Stem and the BADAL X implant in terms of their properties, intramedullary positioning, and the mechanisms leading to successful osseointegration.

Alternatives

Socket prostheses for transfemoral or transtibial amputees have been the gold standard for decades. However, such patients face many challenges to recover autonomous mobility, and an estimated 30% of all amputees report unsatisfactory rehabilitation and 10% cannot use a socket prosthesis at all.

Rationale

Transcutaneous osseointegrated prosthetic systems especially benefit patients who are unable to tolerate socket suspension systems, such as those with short residual limbs and/or bilateral limb loss. The use of a firmly integrated endoprosthetic stem allows patients and surgeons to avoid many of the limitations associated with conventional socket prostheses, such as the need to continually fit and refit the socket to match an ever-changing stump6,14-19. Discussion between patients who are considering an osseointegrated prosthesis and those who have already received one ("peer patients") has proven to be a powerful tool to prevent unrealistic expectations. Patients with a transhumeral amputation especially benefit from the stable connection between the residual limb and exoprosthesis. Motion of the affected and even the contralateral shoulder is no longer impaired, as straps and belts are dispensable. Furthermore, transmission of myoelectric signals from surrounding muscles to the prosthesis is fundamentally improved. However, comorbidities such as diabetes mellitus or peripheral arterial disease require careful counseling, even if these conditions were not responsible for the loss of the limb. Transcutaneous osseointegrated prosthetic systems for replacement of an upper or lower limb might not be an option in patients who are unable, for any reason, to take adequate care of the stoma.

Expected Outcomes

Despite subtle differences between the systems utilized for the intramedullary anchoring of the prosthetic stem, all data indicate that mobility and quality of life significantly increase while the frequency of stoma infections is remarkably low as long as the patient is able to follow simple postoperative care protocols2-5,9,10,13-19.

Important Tips

The impaction pressure of the implant depends on the diameter of the implant and the quality of the residual bone (i.e., the time interval between the amputation and the implantation of the prosthetic stem). The extent of reaming of the inner cortex of the residual bone must be adapted to these conditions. The standard Endo-Fix Stem and BADAL X implant are both slightly curved to adapt to the physiological shape of the femur. Thus, the surgeon must be sure to insert the implant in the right position and at the correct rotational alignment. When preparing a short femoral stump, carefully identify the exact transection level in order to obtain enough bone stock to anchor the implant in the correct intramedullary position for an additional locking screw into the femoral neck and head. Depending on the residual length of the humerus and the press-fit stability of the implant, the utilization of locking screws is optional, as a notch at the distal end of the implant guarantees primary rotational stability.

Acronyms and Abbreviations

TOPS = transcutaneous osseointegrated prosthesis systemsEEP = endo-exo prosthesisMRSA = methicillin-resistant staphylococcus aureusa.p. = anteroposteriorK-wire = Kirschner wireCT = computed tomographyDCA = double conus adapterOFP = osseointegrated femur prosthesis.

Thighplasty at the Time of Stage-1 Bone-Anchored Osseointegration Surgery

Background

For patients with transfemoral amputations and difficulty tolerating conventional socket-based prostheses, osseointegrated (OI) implants have enabled increased prosthetic use, improved patient satisfaction, and shown promising functional outcomes1,2. Although the use of OI implants effectively eliminates the soft-tissue-related challenges that have plagued socket-based prostheses, the presence of a permanent, percutaneous implant imparts a host of new soft-tissue challenges that have yet to be fully defined. In patients undergoing OI surgery who have redundant soft tissue, we perform a thighplasty to globally reduce excess skin and fat, tighten the soft-tissue envelope, and improve the contour of the residual limb.

Description

First, the orthopaedic surgical team prepares the residual femur for implantation of the OI device. After the implant is inserted, the residual hamstrings and quadriceps musculature are closed over the end of the femur, and the subcutaneous tissue and skin are closed in a layered fashion. Although the anatomic location and amount of excess soft tissue are patient-dependent, we perform a standard pinch test to determine the amount of soft tissue that can be safely removed for the thighplasty. Once the proposed area of resection is marked, we proceed with longitudinal, sharp dissection down to the level of the muscular fascia. At this point, we use another pinch test to confirm the amount of soft-tissue resection that will allow for adequate resection without undue tension3. Excess subcutaneous fat and skin are carefully removed along the previously marked incisions, typically overlying the medial compartment of the thigh in the setting of patients with transfemoral amputations. The thighplasty incision is closed in a layered fashion over 1 or 2 Jackson-Pratt drains, depending on the amount of resection.

Alternatives

Depending on the amount of redundant soft tissue, thighplasty may not be necessary at the time of OI surgery; however, in our experience, excess soft tissue surrounding the transcutaneous aperture can predispose the patient to increased shear forces at the aperture, increased drainage, and increased risk of infection4.

Rationale

Although superficial infectious complications are most common following OI surgery, the need for soft-tissue refashioning and excision is one of the most common reasons for reoperation1,5. Our group has been more aggressive than most in our use of a vertical thighplasty procedure to globally reduce soft-tissue motion in the residual limb to avoid reoperation.

Expected Outcomes

Although much of the OI literature has focused on infectious complications, recent studies have demonstrated reoperation rates of 18% to 36% for redundant soft tissue following OI surgery1,5. We believe that thighplasty at the time of OI not only reduces the likelihood of reoperation but may also decrease infectious complications by reducing relative motion and inflammation at the skin-implant interface4,6.

Important Tips

The thighplasty procedure is ideally performed as part of the first stage of the OPRA (Osseointegrated Prosthesis for the Rehabilitation of Amputees) procedure to limit the likelihood of problematic ischemia-related complications.We utilize a confirmatory pinch test both before and throughout the thighplasty procedure to ensure adequate resection without undue tension.The thighplasty excision pattern utilizes a long vertical limb designed to decrease the circumferential laxity of the residual limb. Maximal tension is borne on the vertical limb and not on the transverse extensions, as these are prone to scar widening and distortion of surrounding tissues.Closed-suction drainage is utilized liberally to decrease the likelihood of a symptomatic seroma.

Acronyms and Abbreviations

OI = osseointegratedOPRA = Osseointegrated Prosthesis for the Rehabilitation of AmputeesPVNS = pigmented villonodular synovitisT-GCT = tenosynovial giant-cell tumor.BMI = body mass indexPMH = past medical history.

Mangled extremity: limb salvage for reconstruction versus primary amputation

PURPOSE OF REVIEW

While MESS has historically influenced limb salvage versus amputation decisions, its universal applicability remains uncertain. With trauma systems expanding and advancements in trauma care, the need for a nuanced understanding of limb salvage has become paramount.

RECENT FINDINGS

Recent literature reflects a shift in the management of mangled extremities. Vascular surgery, plastic surgery, and technological advancements have garnered attention. The MESS's efficacy in predicting amputation postvascular reconstruction has been questioned. Machine learning techniques have emerged as a means to predict peritraumatic amputation, incorporating a broader set of variables. Additionally, advancements in socket design, such as automated adjustments and bone-anchored prosthetics, show promise in enhancing prosthetic care. Surgical strategies to mitigate neuropathic pain, including targeted muscle reinnervation (TMR), are evolving and may offer relief for amputees. Predicting the long-term course of osteomyelitis following limb salvage is challenging, but it significantly influences patient quality of life.

SUMMARY

The review underscores the evolving landscape of limb salvage decision-making, emphasizing the need for personalized, patient-centered approaches. The Ganga Hospital Score (GHS) introduces a nuanced approach with a 'grey zone' for patients requiring individualized assessments. Future research may leverage artificial intelligence (AI) and predictive models to enhance decision support. Overall, the care of mangled extremities extends beyond a binary choice of limb salvage or amputation, necessitating a holistic understanding of patients' injury patterns, expectations, and abilities for optimal outcomes.

In vitro and in silico methods for the biomechanical assessment of osseointegrated transfemoral prostheses: a systematic review

The amputee population according to the World-Health-Organization is about 40 million. However, there is a high abandon rate of socket prostheses for the lower limb (25%-57%). The direct connection between the external prosthesis and the patient's bone makes osseointegrated prostheses for transfemoral amputees advantageous (e.g., improvement of the motor control) compared to socket prostheses, which are currently the gold standard. However, similarly to other uncemented prostheses, the osseointegrated ones are at risk of aseptic loosening and adverse bone remodelling caused by stress-shielding. The preclinical assessment of these prostheses has already been evaluated using different methods which did not provide unanimous and comparable evidence. To compare data from different investigations, a clear and detailed overview of the methods used to assess the performance is necessary. In this review 17 studies investigating the primary stability, stress shielding and stress concentration of osseointegrated transfemoral prostheses are examined. Primary stability consists in the biomechanical stability upon implant insertion. Primary stability is assessed measuring extraction force (either with a pull-out or a push-out test) and micromotion at the interface between the implant and the host bone with LVDT (in vitro test) or numerical models. Stress-shielding causes adaptive changes in the bone density around metal implants, and thus in the bone strength and stiffness. Stress-shielding is assessed with strain gauges or numerical models measuring the load transfer and the strain distribution on the surface of the femur, and between the implant and the bone respectively. Stress concentration can lead to the formation of cracks inside the bone, resulting in fractures. The stress concentration is assessed measuring the load transfer and the strain energy density at the interface between the implant and the bone, using numerical models. As a result, a global view and consensus about the methods are missing from all these tests. Indeed, different setup and loading scenario were used in the in vitro test, while different model parameters (e.g., bone properties) were used in the numerical models. Once the preclinical assessment method is established, it would be important to define thresholds and acceptance criteria for each of the possible failure scenarios investigated.

The safety of one-stage versus two-stage approach to osseointegrated prosthesis for limb amputation

Aims

Safety concerns surrounding osseointegration are a significant barrier to replacing socket prosthesis as the standard of care following limb amputation. While implanted osseointegrated prostheses traditionally occur in two stages, a one-stage approach has emerged. Currently, there is no existing comparison of the outcomes of these different approaches. To address safety concerns, this study sought to determine whether a one-stage osseointegration procedure is associated with fewer adverse events than the two-staged approach.

Methods

A comprehensive electronic search and quantitative data analysis from eligible studies were performed. Inclusion criteria were adults with a limb amputation managed with a one- or two-stage osseointegration procedure with follow-up reporting of complications.

Results

A total of 19 studies were included: four one-stage, 14 two-stage, and one article with both one- and two-stage groups. Superficial infection was the most common complication (one-stage: 38% vs two-stage: 52%). There was a notable difference in the incidence of osteomyelitis (one-stage: nil vs two-stage: 10%) and implant failure (one-stage: 1% vs two-stage: 9%). Fracture incidence was equivocal (one-stage: 13% vs two-stage: 12%), and comparison of soft-tissue, stoma, and mechanical related complications was not possible.

Conclusion

This review suggests that the one-stage approach is favourable compared to the two-stage, because the incidence of complications was slightly lower in the one-stage cohort, with a pertinent difference in the incidence of osteomyelitis and implant failure.

Have Surgery and Implant Modifications Been Associated With Reduction in Soft Tissue Complications in Transfemoral Bone-anchored Prostheses?

BACKGROUND

The most frequently occurring adverse events in individuals with a transfemoral amputation treated with a bone-anchored prosthesis are soft tissue infections and stoma-related complications. These soft tissue complications are believed to be influenced by surgical technique and implant design, but little is known about the effect of changes to treatment on these events.

QUESTIONS/PURPOSES

(1) What is the result of surgical technique and implant modifications on the incidence of soft tissue infections and stoma-related complications in transfemoral bone-anchored prosthesis users, depending on whether they had a conventional stoma and a cobalt-chrome-molybdenum (CoCrMo) osseointegration implant (treatment period 2009 to 2013) or a shallower stoma and titanium osseointegration implant (2015 to 2018)? (2) What is the incidence of serious complications, such as bone or implant infection, aseptic loosening, intramedullary stem breakage, and periprosthetic fracture?

METHODS

Between 2009 and 2013, we performed osseointegration implant surgery using a conventional surgical technique and a CoCrMo implant in 42 individuals who had a lower extremity amputation experiencing socket-related problems that resulted in limited prosthesis use. We considered all individuals treated with two-stage surgery with a standard press-fit transfemoral osseointegration implant as potentially eligible for inclusion. Based on this, 100% (42) were eligible, and 5% (two of 42) were excluded because they did not provide informed consent, leaving 95% (40 of 42) for analysis. Between 2015 and 2018, we treated 79 individuals with similar indications with osseointegration implant surgery, now also treating individuals with dysvascular amputations. We used an adapted surgical technique resulting in a shallower stoma combined with a titanium implant. Using the same eligibility criteria as for the first group, 51% (40 of 79) were eligible; 49% (39 of 79) were excluded because they were treated with transtibial amputation, a patient-specific implant, or single-stage surgery and 1% (one of 79) were lost before the 2-year follow-up interval, leaving 49% (39 of 79) for analysis. The period of 2013 to 2015 was a transitional period and was excluded from analysis in this study to keep groups reasonably comparable and to compare a historical approach with the present approach. Hence, we presented a comparative study of two study groups (defined by surgical technique and implant design) with standardized 2-year follow-up. The risk factors for adverse events were similar between groups, although individuals treated with the shallow stoma surgical technique and titanium implant potentially possessed an increased risk because of the inclusion of individuals with dysvascular amputation and the discontinuation of prolonged postoperative antibiotic prophylaxis. Outcomes studied were soft tissue infections and stoma-related complications (hypergranulation or keloid formation as well as stoma redundant tissue) and bone or implant infection, aseptic loosening, implant stem breakage, periprosthetic fracture, and death.

RESULTS

Patients treated with the shallow stoma surgical technique and titanium implant experienced fewer soft tissue infections (13 versus 76 events, absolute risk 0.17 [95% CI 0.09 to 0.30] versus 0.93 [95% CI 0.60 to 1.45]; p < 0.01), which were treated with less invasive measures, and fewer stoma redundant tissue events (0 versus five events, absolute risk 0 versus 0.06 [95% CI 0.03 to 0.14]) than patients treated with the conventional stoma surgical technique and CoCrMo implant. This was contrasted by an increased incidence of surgical site infections occurring between surgical stages 1 and 2, when no stoma was yet created, after the implementation of treatment changes (conventional surgery and CoCrMo implant versus shallow stoma surgery and titanium implant: one versus 11 events, absolute risk 0.01 [95% CI 0.00 to 0.08] versus 0.14 [95% CI 0.08 to 0.25]; p = 0.02). Patients treated with the shallow stoma surgical technique and titanium implant did not experience serious complications, although bone infections occurred (six events in 8% [three of 40] of patients) in the conventional surgery and CoCrMo implant group, all of which were successfully treated with implant retention.

CONCLUSION

Adaptations to surgical technique and newer implant designs, as well as learning curve and experience, have resulted in a reduced incidence and severity of soft tissue infections and stoma redundant tissue, contrasted by an increase in surgical site infections before stoma creation. Serious complications such as deep implant infection were infrequent in this 2-year follow-up period. We believe the benefits of these treatment modifications outweigh the disadvantages and currently advise surgeons to create a shallower stoma with a stable soft tissue envelope, combined with a titanium implant.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Rehabilitation of Patients with Osseointegrated Prosthesis after Transfemoral Amputation - Literature-based Recommendation for Postoperative Rehabilitative Procedure

BACKGROUND

Osseointegrative implantation after amputation of the lower extremity is a special treatment option. Physiotherapeutic treatment is important for the functional outcome. This study systematically evaluated existing follow-up treatment protocols to establish a literature-based recommendation for postoperative rehabilitation procedures.

METHODOLOGY

A PubMed literature search was conducted on December 10, 2020, using the following search terms: (osseo-integrat* OR endo-exo OR boneanchored OR bone anchored) AND (prosthe*) AND (leg OR lower limb* OR lower extremit* OR transfem* OR transtib*) AND (rehabilitation). 113 publications were found in this context. 10 of them met inclusion criteria. The Cochrane risk of bias tool was used to determine the publications' quality.

RESULTS

Three systematic rehabilitation protocols have been described: Osseointegrated Prostheses for the Rehabilitation of Amputees protocol, Osseointegration Group of Australia Accelerated protocol and Radboud Amputation: rehabilitation protocol for endo-exo femoral prosthesis. There are clear differences in the duration of the rehabilitation protocols. The quality of published studies is limited due to the high risk of bias and low evidence levels (mainly III - V). A concept for long-term rehabilitation has not been described yet.

CONCLUSIONS

There are various protocols for rehabilitation after treatment with osseointegrative prosthesis. Gradually increasing axial weight bearing started shortly after surgery; step-by-step gait training, adaptation of the prosthesis to the new biomechanics and critical patient selection and pre-operative training have been proven useful for successful rehabilitation. Controlled comparative studies, standardised outcome measurements or comparative studies between different protocols are not available. Models for multi-level long-term care have not been described in the literature so far.

Oxygen consumption and gait dynamics in transfemoral bone-anchored prosthesis users compared to socket-prosthesis users: A cross-sectional study

BACKGROUND

A transfemoral bone-anchored prosthesis (BAP) is an alternative for the conventional socket-suspended prosthesis (SSP) in persons suffering from socket-related problems. In these persons, it has been demonstrated to reduce oxygen consumption during walking, which could be related to centre of mass (CoM) and trunk dynamics. However, it remains uncertain whether the same comparative findings are found in SSP-users without any socket-related problems.

RESEARCH QUESTION

Do oxygen consumption, CoM and trunk dynamics during walking differ between satisfied transfemoral SSP- and BAP-users and able-bodied individuals (AB); and are CoM and trunk dynamics and pistoning potential determinants of oxygen consumption?

METHODS

Oxygen consumption was measured while participants walked on a treadmill at preferred speed, 30 % slower, and 30 % faster. At preferred speed, we also evaluated CoM deviation, root-mean-square values (RMS) of mediolateral (ML) CoM and trunk excursions, and pistoning. In the prosthetic users, we evaluated whether oxygen consumption, CoM and trunk dynamics, and pistoning were associated.

RESULTS

We included BAP-users (n = 10), SSP-users (n = 10), and AB (n = 10). SSP-users demonstrated higher oxygen consumption, CoM and trunk RMS ML in comparison to AB during walking. BAP-users showed intermediate results between SSP-users and AB, yet not significantly different from either group. Greater CoM and trunk excursions were associated with higher oxygen consumption; in the SSP-users a greater degree of pistoning, in turn, was found to associate with larger trunk RMS ML.

SIGNIFICANCE

Our results indicate that satisfied SSP-users have increased oxygen consumption compared to AB subjects and use compensatory movements during walking. An assessment of CoM and trunk dynamics, and pistoning during walking may be considered for evaluating whether an individual SSP-user could possibly benefit from a BAP, in addition to the currently used functional tests for evaluating eligibility. This might lead to a larger group of persons with a transfemoral SSP benefiting from this technology.

Comparison of prosthetic mobility and balance in transfemoral amputees with bone-anchored prosthesis vs. socket prosthesis

BACKGROUND

The literature comparing bone-anchored prosthesis (BAP) with socket prosthesis (SP) consistently reports improvement in physical health and quality of life using primarily patient-reported outcome measures (PROMs).

OBJECTIVE

To determine the differences in mobility and balance using performance-based outcome measures and PROMs in people with transfemoral amputations (TFAs) fitted with BAP vs. SP.

STUDY DESIGN

Causal comparative.

METHODS

Two groups of people with TFAs were recruited: one using a BAP (N = 11; mean age ± standard deviation, 44 ± 14.9 years; mean residual limb length as a percentage of the intact femur, 68% ± 15.9) and another group using a SP (N = 11; mean age ± standard deviation, 49.6 ± 16.0 years; mean residual limb length as a percentage of the intact femur, 81% ± 13.9), and completed the 10-meter walk test, component timed-up-and-go, Prosthetic Limb Users Survey of Mobility™ 12-item, and Activities-specific Balance Confidence Scale.

RESULTS

There were no statistically significant differences between the BAP and SP groups in temporal spatial gait parameters and prosthetic mobility as measured by the 10-meter walk test and component timed-up-and-go, yet large effect sizes were found for several variables. In addition, Activities-specific Balance Confidence Scale and Prosthetic Limb Users Survey of Mobility™ scores were not statistically different between the BAP and SP groups, yet a large effect sizes were found for both variables.

CONCLUSIONS

This study found that people with TFA who use a BAP can demonstrate similar temporal spatial gait parameters and prosthetic mobility, as well as self-perceived balance confidence and prosthetic mobility as SP users. Therefore, suggesting that the osseointegration reconstruction surgical procedure provides an alternative option for a specific population with TFA who cannot wear nor have limitations with a SP. Future research with a larger sample and other performance-based outcome measures and PROMs of prosthetic mobility and balance would further determine the differences between the prosthetic options.

Twenty-four months of bacterial colonialization and infection rates in patients with transcutaneous osseointegrated prosthetic systems after lower limb amputation-A prospective analysis

BACKGROUND

Transcutaneous osseointegrated prosthesis systems (TOPS) are alternative rehabilitation methods to socket prosthetics, after limb amputation. TOPS compromise a two-step surgery: starting with the implantation of the stem which is then followed by the creation of the transcutaneous stoma through which the exoprosthesis can be connected. Immediately after surgery, this opening is permanently exposed to pathogens. This study aimed to investigate the dynamics of bacterial colonization of the stoma to analyze whether obligate bacterial colonization leads to a risk of periprosthetic infections after TOPS treatment.

METHODS

This prospective study analyzed data from 66 patients (aged 26-75 years) after TOPS treatment between 2017 and 2019. Microbiological swabs from the stoma were analyzed on the first postoperative day and 3, 6, 12, and 24 months after stoma creation. Infection rates, laboratory values (CRP, leukocyte count, hemoglobin), and body temperature were recorded at these points in time. Statistical analysis was performed using SPSS 28.

RESULTS

The results show the formation of a stable environment dominated by Gram-positive bacteria in the stoma of TOPS patients over 24 months. Staphylococcus aureus, Staphylococcus spp., and Streptococcus spp. were the most common species found. With regard to the cohort up to the 3 months follow-up, 7.9% (five patients) developed infections surrounding the TOPS procedure. In relation to the whole cohort with loss to follow-up of 80.3% at the 24 months follow-up the infection rates increased up to 38.3%.

CONCLUSION

The soft tissue inside and around the transcutaneous stoma is colonialized by multiple taxa and changes over time. A stable Gram-positive dominated bacterial taxa could be a protective factor for ascending periprosthetic infections and could possibly explain the relatively low infection rate in this study as well as in literature.

Osseointegrated prostheses for the rehabilitation of patients with transfemoral amputations: A prospective ten-year cohort study of patient-reported outcomes and complications

Background

Methods

Results

Conclusion

Association Between Osseointegration of Lower Extremity Amputation and Mortality Among Adults

IMPORTANCE

Transcutaneous osseointegration post amputation (TOPA) creates a direct linkage between residual bone and an external prosthetic limb, providing superior mobility and quality of life compared with a socket prosthesis. The causes and potential risks of mortality after TOPA have not been investigated.

OBJECTIVE

To investigate the association between TOPA and mortality and assess the potential risk factors.

DESIGN, SETTING, AND PARTICIPANTS

This observational cohort study included all patients with amputation of a lower extremity who underwent TOPA between November 1, 2010, and October 31, 2021, at a specialty orthopedic practice and tertiary referral hospital in a major urban center. Patients lived on several continents and were followed up as long as 10 years.

EXPOSURES

Transcutaneous osseointegration post amputation, consisting of a permanent intramedullary implant passed transcutaneously through a stoma and connected to an external prosthetic limb.

MAIN OUTCOMES AND MEASURES

Death due to any cause. The hypotheses tested-that patient variables (sex, age, level of amputation, postosseointegration infection, and amputation etiology) may be associated with subsequent mortality-were formulated after initial data collection identifying which patients had died.

RESULTS

A total of 485 patients were included in the analysis (345 men [71.1%] and 140 women [28.9%]), with a mean (SD) age at osseointegration of 49.1 (14.6) years among living patients or 61.2 (12.4) years among patients who had died. Nineteen patients (3.9%) died a mean (SD) of 2.2 (1.7) years (range, 58 days to 5 years) after osseointegration, including 17 (3.5%) who died of causes unrelated to osseointegration (most commonly cardiac issues) and 2 (0.4%) who died of direct osseointegration-related complications (infectious complications), of which 1 (0.2%) was coclassified as a preexisting health problem exacerbated by osseointegration (myocardial infarction after subsequent surgery to manage infection). No deaths occurred intraoperatively or during inpatient recuperation or acute recovery after index osseointegration (eg, cardiopulmonary events). Kaplan-Meier survival analysis with log-rank comparison and Cox proportional hazards regression modeling identified increased age (hazard ratio, 1.06 [95% CI, 1.02-1.09]) and vascular (odds ratio [OR], 4.73 [95% CI, 1.35-16.56]) or infectious (OR, 3.87 [95% CI, 1.31-11.40]) amputation etiology as risk factors. Notable factors not associated with mortality risk included postosseointegration infection and male sex.

CONCLUSIONS AND RELEVANCE

These findings suggest that patients who have undergone TOPA rarely die of problems associated with the procedure but instead usually die of unrelated causes.

Elective transfemoral amputation and simultaneous implantation of a transcutaneous osseointegrated prosthesis stem as salvage treatment after knee joint arthrodesis with poor function: A case report

Background

Surgical reconstruction of anterior cruciate ligament ruptures is a well-established procedure, and although it is for the vast majority of patients without severe complications, total knee joint arthroplasty, arthrodesis of the knee, and finally transfemoral amputation have to be considered in the worst-case scenario.

The case

We report a case of a patient with a 13-year history of recurrent failure after anterior cruciate ligament reconstruction. She claimed she had severely impaired mobility secondary to a knee joint arthrodesis via an Ilizarov circular frame 2 years ago and chronic immobilizing pain, making a permanent medication with opioids necessary. She was aware of the therapeutic options and asked for transfemoral amputation and concomitant supply with a transcutaneous osseointegrated prosthesis system (TOPS).

Procedures

After careful evaluation and clinical work-up, the indication for transfemoral amputation and concomitant implantation of the prosthetic stem into the femoral cavity was secured. Six weeks after the creation of the stoma for coupling of the artificial limb and onset of physiotherapy, balance and gait training were scheduled. Full weight-bearing and walking without crutches were allowed 12 weeks after the index procedure. This sequence of events was paralleled by a series of pre-defined examinations, that is, questionnaires and mobility scores addressing the situation of transfemoral amputees, as well as standardized clinical gait analysis. The latter was performed before surgery and 6, 9, and 18 months after the index procedure.

Outcome

At the time of the index procedure, opioids could be tapered to zero, and the patient quickly regained her walking abilities during the rehabilitation period. Clinical gait analysis confirmed the restoration of bilateral symmetry by mutual approximation of kinematics and kinetics to a standard gait pattern.

Conclusion

The outcome of our patient strengthens the therapeutic potential of a unilateral transfemoral amputation in combination with TOPS. Nevertheless, long-term follow-up is necessary to detect future complications of this approach.

What Are the Risk Factors for Mechanical Failure and Loosening of a Transfemoral Osseointegrated Implant System in Patients with a Lower-limb Amputation?

BACKGROUND

Septic loosening and stem breakage due to metal fatigue is a rare but well-known cause of orthopaedic implant failure. This may also affect the components of the osseointegrated implant system for individuals with transfemoral amputation who subsequently undergo revision. Identifying risk factors is important to minimize the frequency of revision surgery after implant breakage.

QUESTIONS/PURPOSES

(1) What proportion of patients who received an osseointegrated implant after transfemoral amputation underwent revision surgery, and what were the causes of those revisions? (2) What factors were associated with revision surgery when stratified by the location of the mechanical failure and (septic) loosening (intramedullary stem versus dual cone adapter)?

METHODS

Between May 2009 and July 2015, we treated 72 patients with an osseointegrated implant. Inclusion criteria were a minimum follow-up of 5-years and a standard press-fit cobalt-chromium-molybdenum (CoCrMb) transfemoral osseointegrated implant. Based on that, 83% (60 of 72) of patients were eligible; a further 3% (2 of 60) were excluded because of no received informed consent (n = 1) and loss to follow-up (n = 1). Eventually, we included 81% (58 of 72) of patients for analysis in this retrospective, comparative study. We compared patient characteristics (gender, age, and BMI), implant details (diameter of the intramedullary stem, length of the dual cone, and implant survival time), and event characteristics (infectious complications and distal bone resorption). The data were retrieved from our electronic patient file and from our cloud-based database and analyzed by individuals not involved in patient care. Failures were categorized as: (1) mechanical failures, defined as breakage of the intramedullary stem or dual-cone adapter, or (2) (septic) loosening of the osseointegrated implant.

RESULTS

Thirty-four percent (20 of 58) of patients had revision surgery. In 12% (7 of 58) of patients, the reason for revision was due to intramedullary stem failures (six breakages, one septic loosening), and in 22% (13 of 58) of patients it was due to dual-cone adaptor failure (10 weak-point breakages and four distal taper breakages; one patient broke both the weak-point and the dual-cone adapter). Smaller median stem diameter (failure: 15 mm [interquartile range 1.3], nonfailure: 17 mm [IQR 2.0], difference of medians 2 mm; p < 0.01) and higher median number of infectious events (failure: 6 [IQR 11], nonfailure: 1 [IQR 3.0], difference of medians -5; p < 0.01) were associated with revision intramedullary stem surgery. No risk factors could be identified for broken dual-cone adapters.

CONCLUSION

Possible risk factors for system failure of this osteointegration implant include small stem diameter and high number of infectious events. We did not find factors associated with dual-cone adapter weak-point failure and distal taper failure, most likely because of the small sample size. When treating a person with a lower-limb amputation with a CoCrMb osseointegrated implant, we recommend avoiding a small stem diameter. Further research with longer follow-up is needed to study the success of revised patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Bone Bricks: The Effect of Architecture and Material Composition on the Mechanical and Biological Performance of Bone Scaffolds

Large bone loss injuries require high-performance scaffolds with an architecture and material composition resembling native bone. However, most bone scaffold studies focus on three-dimensional (3D) structures with simple rectangular or circular geometries and uniform pores, not able to recapitulate the geometric characteristics of the native tissue. This paper addresses this limitation by proposing novel anatomically designed scaffolds (bone bricks) with nonuniform pore dimensions (pore size gradients) designed based on new lay-dawn pattern strategies. The gradient design allows one to tailor the properties of the bricks and together with the incorporation of ceramic materials allows one to obtain structures with high mechanical properties (higher than reported in the literature for the same material composition) and improved biological characteristics.

Extramedullary Osseointegration-A Novel Design of Percutaneous Osseointegration Prosthesis for Amputees

The percutaneous osseointegrated (OI) prostheses have greatly improved the overall quality of life for amputees. However, the long-term maintenance of the OI prostheses is still challenging. A major problem is bone resorption around the bone-implant-skin interface, which might cause implant loosening or osteomyelitis. Another problem is the breakage of connecting components between the intramedullary implant and external prosthesis due to excessive stress. We designed a novel osseointegration implant by changing the bone-implant contact from the inner cortex to the outer surface of cortical bone. In the current study, we compared the extramedullary cap-shaped implants with the intramedullary screw-type implants in rabbits. Osteointegration was confirmed at the interface of bone to implant contact (BIC) in both implant types. The external implant induced intramedullary bone regeneration in the medullary canal and increased the cortical bone density at the end of the stump. This study provides a new perspective on the design of osseointegration implants which might prevent the currently reported complications of the intramedullary OI systems.

Comparison of functional outcome and patient satisfaction between patients with socket prosthesis and patients treated with transcutaneous osseointegrated prosthetic systems (TOPS) after transfemoral amputation

PURPOSE

The aim of this retrospective analysis was to investigate and evaluate differences in functional outcome and satisfaction of patients treated with a TOPS and patients using socket prosthesis after transfemoral amputation.

METHODS

This retrospective comprehensive analysis included patients from a single hospital, and was conducted between February 2017 and December 2018. Overall n = 139 patients with prosthesis were included and divided into two comparable groups (socket- and TOPS group). Incomplete data sets were excluded. This led to n = 36 participants for the socket- and n = 33 for the TOPS group. Functional outcome and satisfaction were evaluated by Patient Reported Outcome Measures (PROMs). The used PROMs were: Questionnaire for Persons with a Transfemoral Amputation (Q-TFA), EQ5D-5L, Satisfaction with Prosthesis Questionnaire (SAT-PRO), Prosthesis Mobility Questionnaire (PMQ 2.0) and Functional Independence Measure (FIM).

RESULTS

Significant results in favor of TOPS patients were identified for the EQ-5D 5L (p = 0.004), Q-TFA (p = 0.000), SAT-PRO (p = 0.000) and PMQ 2.0 (p = 0.000). For FIM, no statistical significance was found (p = 0.318).

CONCLUSION

In this study, transfemoral amputees treated with an osseointegrated prosthetic attachment (TOPS) showed significantly higher scores for mobility and satisfaction. This demonstrates the high potential of TOPS in the prosthetic treatment of patients with transfemoral amputation with regard to their functional abilities in daily life.

Patient-reported benefits of bone-anchored transfemoral prostheses as assessed by MedTech20: A general outcome measure for medical products

BACKGROUND

The medical community demands evidence for the benefits of medical devices such as bone-anchored prostheses (BAPs). MedTech20  is a novel instrument aiming to address general benefits of medical devices.

OBJECTIVE

To describe general patient-reported benefits of BAPs measured with MedTech20.

STUDY DESIGN

This is a cross-sectional descriptive survey.

METHODS

Patients treated in Sweden who had used a BAP for >1 year were mailed the MedTech20  Questionnaire. Responses to each attribute were described, and the MedTech20   Index (0-1), in which a higher figure represents larger benefits from the product, was calculated. Index values were compared based on demographic variables (sex, unilateral or bilateral transfemoral amputation (TFA), and those having experienced any complication of implant parts or the prosthetic connection device).

RESULTS

The response rate was 72%. The 62 participants (41 men and 21 women; mean age 57 years) had 11 ± 6.9 mean years of BAP experience. Single attributes stated as highly relevant and with high benefit for BAPs included perceived reliability, perceived safety, sense of control of the disability, facilitation of movement outside home, no discomfort at use, and ease of use. Attributes with less relevance included aid to remember tasks, reduction of barriers to a good sleep, and reduced sense of compromised integrity. The MedTech20  Index was 0.655 ± 0.188 and was not statistically significantly different based on any of the demographic variables.

CONCLUSIONS

By using a general measure on attributes of medical devices, this study provides new insights strengthening the evidence regarding the benefits that BAPs provide for patients with TFA who had difficulties with socket-suspended prostheses.

Biological sealing and integration of a fibrinogen-modified titanium alloy with soft and hard tissues in a rat model

Percutaneous or transcutaneous devices are important and unique, and the corresponding biological sealing at the skin-implant interface is the key to their long-term success. Herein, we investigated the surface modification to enhance biological sealing, using a metal sheet and screw bonded by biomacromolecule fibrinogen mediated via pre-deposited synthetic macromolecule polydopamine (PDA) as a demonstration. We examined the effects of a Ti-6Al-4V titanium alloy modified with fibrinogen (Ti-Fg), PDA (Ti-PDA) or their combination (Ti-PDA-Fg) on the biological sealing and integration with skin and bone tissues. Human epidermal keratinocytes (HaCaT), human foreskin fibroblasts (HFF) and preosteoblasts (MC3T3-E1), which are closely related to percutaneous implants, exhibited better adhesion and spreading on all the three modified sheets compared with the unmodified alloy. After three-week subcutaneous implantation in Sprague-Dawley (SD) rats, the Ti-PDA-Fg sheets could significantly attenuate the soft tissue response and promote angiogenesis compared with other groups. Furthermore, in the model of percutaneous tibial implantation in SD rats, the Ti-PDA-Fg screws dramatically inhibited epithelial downgrowth and promoted new bone formation. Hence, the covalent immobilization of fibrinogen through the precoating of PDA is promising for enhanced biological sealing and osseointegration of metal implants with soft and hard tissues, which is critical for an orthopedic percutaneous medical device.

The bone anchored prostheses for amputees - Historical development, current status, and future aspects

In the past 50 years, bone anchored prostheses have evolved from a concept for experimental treatment to a rapidly developing area in orthopedics and traumatology. Up to date, there are dozens of centers in the world providing osseointegration amputation reconstructions and more than a thousand patients using the bone anchored prostheses. Compared with conventional socket prostheses, the bone anchored prosthesis by osseointegration avoids the debilitating problems related with soft tissues. It also provides physiological weight bearing, improved range of motion, and sensory feedback, all of which contribute to the improvement on quality of life for amputees. The present article briefly reviews the historical development of osseointegration surgery for amputation reconstruction and the current challenges. The implant design characters and surgical techniques of the two types of implants; the screw-type implant (presented by the OPRA system), and the press-fit implants (presented by EEP and OPL systems) are described. The major complications, infections and mechanical failures, are discussed in detail based on the latest evidence. Future aspects and experimental trials aiming to overcome the current challenges are presented.