Osteomyelitis Risk in Patients With Transfemoral Amputations Treated With Osseointegration Prostheses

Evaluation of the Transfemoral Bone-Implant Interface Properties Using Vibration Analysis

Evaluating the bone-implant interface (BII) properties of osseointegrated transfemoral (TFA) implants is important for early failure detection and prescribing loads during rehabilitation. The objective of this work is to derive and validate a 1D finite element (FE) model of the Osseointegrated Prosthetic Limb (OPL) TFA system that can: (1) model its dynamic behaviour and (2) extract the BII properties. The model was validated by: (1) comparing the 1D FE formulation to the analytical and 3D FE solutions for a simplified cylinder, (2) comparing the vibration modes of the actual TFA geometry using 1D and 3D FE models, and (3) evaluating the BII properties for three extreme conditions (LOW, INTERMEDIATE, and HIGH) generated using 3D FE and experimental (where the implant was embedded, using different adhesives, in synthetic femurs) signals for additional validation. The modes predicted by the 1D FE model converged to the analytical and the 3D FE solutions for the cylinder. The 1D model also matched the 3D FE solution with a maximum frequency difference of 2.02% for the TFA geometry. Finally, the 1D model extracted the BII stiffness and the system's damping properties for the three conditions generated using the 3D FE simulations and the experimental INTERMEDIATE and HIGH signals. The agreement between the 1D FE and the 3D FE solutions for the TFA geometry indicates that the 1D model captures the system's dynamic behaviour. Distinguishing between the different BII conditions demonstrates the 1D model's potential use for the non-invasive clinical evaluation of the TFA BII properties.

Integrating Upper-Limb Prostheses with the Human Body: Technology Advances, Readiness, and Roles in Human-Prosthesis Interaction

Significant advances in bionic prosthetics have occurred in the past two decades. The field's rapid expansion has yielded many exciting technologies that can enhance the physical, functional, and cognitive integration of a prosthetic limb with a human. We review advances in the engineering of prosthetic devices and their interfaces with the human nervous system, as well as various surgical techniques for altering human neuromusculoskeletal systems for seamless human-prosthesis integration. We discuss significant advancements in research and clinical translation, focusing on upper limbprosthetics since they heavily rely on user intent for daily operation, although many discussed technologies have been extended to lower limb prostheses as well. In addition, our review emphasizes the roles of advanced prosthetics technologies in complex interactions with humans and the technology readiness levels (TRLs) of individual research advances. Finally, we discuss current gaps and controversies in the field and point out future research directions, guided by TRLs.

The nonsalvageable tibia: amputation and prosthetics

Mangled extremities are a challenging problem for the orthopaedic surgeon. The decision for salvage versus amputation is multifactorial. Several work groups have attempted to create scoring systems to guide treatment, but each case must be regarded individually. As surgical technique and prosthetics continue to improve, amputations should be seen as a viable reconstructive option, rather than failure. This article reviews scoring systems for the mangled extremity, outcomes on salvage versus amputation, amputation surgical technique, and prosthetic options.

Soft and Hard Tissue Integration around Percutaneous Bone-Anchored Titanium Prostheses: Toward Achieving Holistic Biointegration

A holistic biointegration of percutaneous bone-anchored metallic prostheses with both hard and soft tissues dictates their longevity in the human body. While titanium (Ti) has nearly solved osseointegration, soft tissue integration of percutaneous metallic prostheses is a perennial problem. Unlike the firm soft tissue sealing in biological percutaneous structures (fingernails and teeth), foreign body response of the skin to titanium (Ti) leads to inflammation, epidermal downgrowth and inferior peri-implant soft tissue sealing. This review discusses various implant surface treatments/texturing and coatings for osseointegration, soft tissue integration, and against bacterial attachment. While surface microroughness by SLA (sandblasting with large grit and acid etched) and porous calcium phosphate (CaP) coatings improve Ti osseointegration, smooth and textured titania nanopores, nanotubes, microgrooves, and biomolecular coatings encourage soft tissue attachment. However, the inferior peri-implant soft tissue sealing compared to natural teeth can lead to peri-implantitis. Toward this end, the application of smart multifunctional bioadhesives with strong adhesion to soft tissues, mechanical resilience, durability, antibacterial, and immunomodulatory properties for soft tissue attachment to metallic prostheses is proposed.

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.

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.

Single-stage transcutaneous osseointegrated prosthesis for above-knee amputations including an antibiotic-loaded hydrogel. Preliminary results of a new surgical protocol

INTRODUCTION

Patients with above-knee amputations (AKA) are normally treated with the traditional socket-mounted prosthesis (SMP), which is associated with a high incidence of problems. Osseointegration has been proposed as a promising option for avoiding many common SMP drawbacks. Several concerns have arisen regarding amputee osseointegration, however, mainly with respect to infection. We report on the safety of a single-stage osseointegration protocol using an antibiotic-loaded hydrogel to coat the intramedullary implant.

MATERIALS AND METHODS

We retrospectively reviewed all AKA cases treated at our center between January 2019 and April 2022, in which a transcutaneous osseointegrated implant was used in a single-stage strategy, together with a rapid-resorbable hydrogel loaded with vancomycin and gentamicin. The specific protocol used, infection rate, implant osseointegration rate and implant survivorship were determined after a minimum follow-up of 12 months.

RESULTS

Eleven osseointegration cases were included in the study, with an average of 16 years post-amputation (range: 3-35 years). After a median follow-up of 24 months (range 12-49 months) no patient had suffered any implant-related infection. Osseointegration of the implant had been achieved in all cases. The mid-term survivorship of the implant in our series was 100 % at the end of follow-up. Radiographs of all cases showed no loosening of the implant. Further, 91 % of the series patients were able to walk without restrictions after the rehabilitation process.

CONCLUSIONS

The single-stage osseointegration protocol for AKA, using a rapid-resorbable hydrogel loaded with vancomycin and gentamicin, yields low rates of implant-related deep infection. This protocol consistently delivers high rates of radiological osseointegration, with no hydrogel-associated complications.

Development of an evidence-based diagnostic algorithm for infection in patients with transcutaneous osseointegration following amputation

Introduction: Transcutaneous osseointegration following amputation (TOFA) confers better mobility and quality of life for most patients versus socket prosthesis rehabilitation. Peri-TOFA infection remains the most frequent complication and lacks an evidence-based diagnostic algorithm. This study's objective was to investigate preoperative factors associated with positive intraoperative cultures among patients suspected of having peri-TOFA infection in order to create an evidence-based diagnostic algorithm. Methods: We conducted a retrospective study of 83 surgeries (70 patients) performed to manage suspected lower-extremity peri-TOFA infection at a specialty orthopedic practice and tertiary referral hospital in a major urban center. The diagnosis of infection was defined as positive intraoperative cultures. Preoperative patient history (fevers, subjective pain, increased drainage), physician examination findings (local cellulitis, purulent discharge, implant looseness), and laboratory data (white blood cell count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and external swab culture) were evaluated for association with subsequent positive intraoperative cultures using regression and area under receiver-operator curve (AUC) modeling. Results: Peri-implant limb pain (highly correlated with infection), ESR > 30 (highly correlated against infection), positive preoperative swab (moderately correlated with infection), gross implant motion (moderately correlated against infection), and erythema or cellulitis of the transcutaneous region (mildly correlated with infection) were variables included in the best AUC model, which achieved an 85 % positive predictive value. Other clinical findings and laboratory values (notably CRP and WBC) were non-predictive of infection. Conclusions: This seminal investigation to develop a preoperative diagnostic algorithm for peri-TOFA infection suggests that the clinical examination remains paramount. Further evaluation of a wider spectrum of clinical, laboratory, and imaging data, consistently and routinely collected with prospective data techniques in larger cohorts of patients, is necessary to create a robust predictive algorithm.

Osseointegration for Lower Limb Amputation: Understanding the Risk Factors and Time Courses of Soft Tissue Complications

PURPOSE

Lower-limb osseointegrated prostheses are a novel alternative to traditional socket-suspended prostheses, which are often associated with poor fit, soft tissue damage, and pain. Osseointegration eliminates the socket-skin interface and allows for weight-bearing directly on the skeletal system. However, these prostheses can also be complicated by postoperative issues that can negatively impact mobility and quality of life. Little is known about the incidence of or risk factors for these complications as few centers currently perform the procedure.

METHODS

A retrospective analysis was performed on all patients who underwent single-stage lower limb osseointegration at our institution between 2017 and 2021. Patient demographics, medical history, operative data, and outcomes were collected. Fisher exact test and unpaired t tests were performed to identify risk factors for each adverse outcome, and time-to-event survival curves were generated.

RESULTS

Sixty patients met our study criteria: 42 males and 18 females with 35 transfemoral and 25 transtibial amputations. The cohort had an average age of 48 years (range, 25-70 years) and follow-up period of 22 months (range, 6-47 months). Indications for amputation were trauma (50), prior surgical complication (5), cancer (4), and infection (1). Postoperatively, 25 patients developed soft tissue infections, 5 developed osteomyelitis, 6 had symptomatic neuromas, and 7 required soft tissue revisions. Soft tissue infections were positively correlated with obesity and female sex. Neuroma development was associated with increased age at osseointegration. Neuromas and osteomyelitis were both associated with decreased center experience. Subgroup analysis by amputation etiology and anatomic location did not show significant differences in outcomes. Notably, hypertension (15), tobacco use (27), and prior site infection (23) did not correlate with worse outcomes. Forty-seven percent of soft tissue infections occurred in the 1 month after implantation, and 76% occurred in the first 4 months.

CONCLUSIONS

These data provide preliminary insights into risk factors for postoperative complications arising from lower limb osseointegration. These factors are both modifiable (body mass index, center experience), and unmodifiable (sex, age). As this procedure continues to expand in popularity, such results are necessary to inform best practice guidelines and optimize outcomes. Further prospective studies are needed to confirm the above trends.

Neuromuscular adaptations after osseointegration of a bone-anchored prosthesis in a unilateral transfemoral amputee - a case study

PURPOSE

Many individuals with a lower limb amputation experience problems with the fitting of the socket of their prosthesis, leading to dissatisfaction or device rejection. Osseointegration (OI)- the implantation of a shaft directly interfacing with the remaining bone- is an alternative for these patients. In this observational study, we investigated how bone anchoring influences neuromuscular parameters during balance control in a patient with a unilateral transfemoral amputation.

MATERIAL AND METHODS

Center of pressure (CoP) and electromyography (EMG) signals from muscles controlling the hip and the ankle of the intact leg were recorded during quiet standing six months before and one and a half years after this patient underwent an OI surgery. Results were compared to a control group of nine able-bodied individuals.

RESULTS

Muscle co-activation and EMG intensity decreased after bone anchoring, approaching the levels of able-bodied individuals. Muscle co-activation controlling the ankle decreased in the high-frequency range, and the EMG intensity spectrum decreased in the lower-frequency range for all muscles when vision was allowed. With eyes closed, the ankle extensor muscle showed an increased EMG intensity in the high-frequency range post-surgery. CoP length increased in the mediolateral direction of the amputated leg.

CONCLUSIONS

These findings point to shifts in the patient's neuromuscular profile towards the one of able-bodied individuals.

Sex and gender differences in quality of life and related domains for individuals with adult acquired lower-limb amputation: a scoping review

PURPOSE

To understand what is known about sex and gender differences in quality of life (QoL) and related domains for individuals with an adult acquired lower limb amputation (LLA).

METHODS

A computer-assisted literature search of four online databases was completed. Articles were included if they incorporated sex or gender as part of their data analysis with a focus on QoL-related domains. Data were analyzed using descriptive numerical analysis and thematic analysis.

RESULTS

One hundred and eleven articles were included in this review. Women were under-represented across studies, with most of the participants being men. No articles described the inclusion of trans or non-binary persons. Differences by sex or gender were reported by 66 articles. Articles reporting on gender seldom provided descriptions of how gender was defined. Overall, women/females seemed to have worse outcomes in terms of prosthesis-related outcomes, mental health, and return to occupations.

CONCLUSION

Articles included in this review were not clear with how gender was defined. In order for more targeted interventions that account for sex and gender differences, studies need to be more forthcoming about how they use and define gender. Future research should seek to include gender non-conforming participants to identify additional needs.Implications for rehabilitationSex and gender are important constructs that influence outcomes following lower limb amputation.Rehabilitation professionals should consider sex and gender-specific outcomes when tailoring programs to ensure ethical clinical care.

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

Biomechanical and histomorphometric evaluation of skin integration on titanium and PEEK implants with different surface treatments

Percutaneous implants are frequently affected by bacterial growth at the skin-implant interface. Integration between implant and surrounding skin is important to prevent bacteria from spreading to the underlying tissue. The standard method to evaluate skin-implant integration is by histomorphometry on samples which have been placed in tissue grown in vivo or ex vivo. In this study, a biomechanical method was developed and evaluated. The integration of implants into porcine skin was studied in an ex vivo model, where pig skin samples were cultivated in a nutrient solution. Cylindrical shaped implants, consisting of polyether ether ketone (PEEK) and titanium (Ti) with different surface treatments, were implanted in the skin tissue and the skin was grown in nutrient solution for 2 weeks. The implants were then extracted from the implantation site and the mechanical force during extraction was measured as a quantitative assessment of skin-implant integration. Implants from each group were also processed for histomorphometry and the degree of epidermal downgrowth (ED) and tissue to implant contact (TIC) was measured. A higher mean pullout force was observed for the PEEK implants compared to the Ti implants. Applying nanosized hydroxyapatite (HA) on Ti and PEEK increased the pullout force compared to uncoated controls, 24% for machined and 70% for blasted Ti, and 51% for machined PEEK. Treatment of Ti and PEEK with nanosized zirconium phosphate (ZrP) did not increase the pullout force. The histomorphometry analysis showed correlation between ED and pullout force, where the pullout force was inversely proportional to ED. For TIC, no significant differences were observed between the groups of same material (i.e. Ti, Ti+HA, Ti+ZrP, and PEEK, PEEK + HA, PEEK + ZrP), but it was significantly higher for PEEK compared to Ti. Scanning electron microscopy analysis was done on samples before and after the pullout tests, showing that the ZrP coating was unaffected by the 2 week ex vivo implantation and pullout procedure, no dissolution or detachment of the coating was observed. For the HA coating, a loss of coating was seen on approximately 5% of the total surface area of the implant. Graphical abstract.

Microbiological Profile of the Implantation Zone under Different Mechanical Compression of Percutaneous Implants: Experimental Study

Background. Infection of percutaneous implants in patients with limb amputation is the most common complication. Aim of the study evaluation of the microflora in the implantation zone depending on the mechanical compression of the implant in conditions of its additional external fixation. Methods. The study was performed on 36 male rabbits. The tibia of all the rabbits was sawn at the border of the upper and middle parts. The medullary canal was reamed and a percutaneous implant was placed in the tibial stump. The segment and the implant were fixed with an Ilizarov apparatus. An additional compression device was installed in 30 animals. We used 5 compression modes, accordingly, 6 experimental groups were formed, 6 animals in each: group 1 without compression, group 2 compression on the implant with force of 0.053 N/mm2, group 3 compression on the implant with force of 0.105 N/mm2, group 4 compression on the implant with force of 0.158 N/mm2, group 5 compression on the implant with force of 0.211 N/mm2, group 6 compression on the implant with force of 0.263 N/mm2. The restraint was removed 6 weeks after implantation for a total follow-up of 26 weeks. The microflora of the place where the implant enters the skin (the implant / skin interface) was investigated, the level of blood leukocytes and the level of C-reactive protein in blood serum were determined. Results. On days 9-10 after implantation, significant differences in the microbial landscape were found at the site of the exit of the metal implant in animals of different groups. The largest number of strains was found in animals of groups 1, 5 and 6, the smallest in groups 2 and 3. The most frequently detected strains: S. saprophyticus and Enterococcus spp. It was found that the greatest statistically significant increase in the level of CRP in the blood serum was observed in animals of group 6. The level of leukocytes in animals of all groups did not change statistically significantly relative to preoperative values. Animals with better osseointegration (groups 2 and 3 no cases of implant loss) showed a minimal number of growing strains. Conclusions. The microbiological profile of the implantation zone of percutaneous implants changes depending on the amount of mechanical compression. The optimal mode is 0.053-0.105 N/mm2.

A preliminary, observational study using whole-blood RNA sequencing reveals differential expression of inflammatory and bone markers post-implantation of percutaneous osseointegrated prostheses

AIMS

While the benefits of direct skeletal attachment of artificial limbs are well recognized, device failure due to infection and insufficient osseointegration remain obstacles to obtaining consistently successful outcomes. Currently, the potential for device failure is assessed by subjective pain, clinical function scores, radiographic evidence of bone atrophy, and the presence of radiolucent lines at the bone-implant interface, and subjective pain and function scores. Our hypothesis is that measurable biological indices might add another objective means to assess trends toward bone and stomal healing. This longitudinal cohort study was undertaken to identify potential serological biomarkers suggestive of bone remodeling and the presence of stomal tissue inflammation.

METHODS

Ten unilateral transfemoral amputee veterans, who were implanted with a percutaneous osseointegrated (OI) skeletal limb docking system, were recruited to participate in this IRB-approved study. Venous blood samples were obtained from before the Stage 1 Surgery up to 1 year following the Stage 2 Surgery. Whole-blood RNA was extracted, sequenced, mapped, and analyzed. Of the significant differentially expressed (DEGs) genes (p<0.05) identified, four genes of interest (IL12B, IL33, COL2A1, and SOST) were validated using qPCR. Enrichment analysis was performed to identify significant (p<0.01) Gene Ontology (GO) terms.

RESULTS

Most differentially expressed genes were only detected at PoS1 immediately after the first surgery. Of the significant genes identified, IL12B and IL33 were related to inflammation, and COL2A1 and SOST were associated with bone remodeling. These four genes were identified with greater than 20 log fold-change.

CONCLUSION

Whole-blood RNA-seq data from 10 patients who previously underwent percutaneous osseointegrated lower limb implantation revealed four genes of interest that are known to be involved in inflammation or bone remodeling. If verified in future studies, these genes may serve as markers for predicting optimal bone remodeling and stomal tissue healing following OI device implantation.

Osseointegration Amputation Reconstruction

Purpose of Review

To review the topic of osseointegration amputation reconstruction, which inserts a transcutaneous metal implant into the remaining intramedullary bone of a person with an amputation to facilitate a direct bone-anchored connection to an external prosthesis, eliminating the molded socket interface.

Recent Findings

Evidence continues to build that patients function better and have a higher quality of life with osseointegration implants compared with traditional socket prosthetics. The indications for osseointegration are expanding to additional patient populations and the long-term outcomes available are favorable which supports the continued refinement and utilization of the technology.

Summary

Osseointegration implants offer people with amputations freedom from burdensome socket prosthetics while improving function and quality of life. Mild infections at the skin interface are common but managed effectively with oral antibiotics and rarely lead to deep infection and implant removal. Other serious complications like hip or implant fracture are also uncommon. Additional long-term outcomes are needed along with technologic refinements, especially at the skin implant interface.

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.

Attachment of a Myoelectric Prosthesis After Transulnar Osseointegration Implantation: A 2-Patient Case Study

CASE

This report discusses 2 successful cases of traumatic transulnar amputees who underwent osseointegration implantation. After surgery, a myoelectric prosthetic equipped with Coapt (Chicago, IL) recognition software was attached directly to the implant. Patients underwent training with pattern recognition software to learn to control the myoelectric prosthetic with the multiarticulating hand and wrist. Both implants osseointegrated without signs of loosening at the most recent follow-up of 18 months and 2 years, respectively. Prosthetic control gradually improved to allow activities of daily living.

CONCLUSION

These cases demonstrate what can be achieved with interdisciplinary coordination between surgeons, prosthetists, and emerging technologies.

Mehrstufige Rehabilitation bei osseointegrierter Prothesenversorgung

Die erfolgreiche Wiederherstellung der Gehfähigkeit nach Amputation einer unteren Extremität ist eine große Herausforderung. Transkutane osseointegrierte Prothesen gewinnen als modernes Behandlungsverfahren zunehmend an Bedeutung. Diese Kasuistik vergleicht die mehrstufige Rehabilitation eines Patienten, welcher primär mittels schaftgeführter und sekundär mittels osseointegrierter Prothese versorgt wurde.

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.

Early Experience with Femoral and Tibial Bone-Anchored Osseointegration Prostheses

Background:

The use of bone-anchored osseointegration implants for amputation reconstruction continues to expand throughout the world. Benefits are thought to include the elimination of socket-related problems and improved control and proprioception of the prosthetic limb. Reported outcomes have been positive, but skepticism remains with regard to the risk of infection and implant failure. Further results from early adopters are therefore needed prior to widespread acceptance and regulatory approval.

Methods:

A retrospective review of the first 31 consecutive patients who underwent implantation of a press-fit osseointegration implant of the femur or tibia with follow-up of at least 6 months was performed. The primary outcome was the patient-reported Questionnaire for persons with a Transfemoral Amputation (Q-TFA) measured preoperatively and 6 to 12 months postoperatively. Patient-Reported Outcomes Measurement Information System (PROMIS) and Limb Deformity-Scoliosis Research Society (LD-SRS) scores, 2-minute and 6-minute walk tests, and complications were also recorded.

Results:

In this study, 18 femoral reconstructions and 13 tibial reconstructions were performed, with a mean follow-up (and standard deviation) of 21.1 ± 9.2 months. Twenty-eight reconstructions were single-stage implantations. All Q-TFA domains improved significantly (p < 0.001) from preoperatively to postoperatively, including the global score (25.0 ± 17.4 to 81.2 ± 17.6 points), prosthetic use (50.2 ± 39.9 to 91.2 ± 18.7 points), prosthetic mobility (49.7 ± 26.9 to 81.4 ± 21.5 points), and prosthetic problems (46.4 ± 17.5 to 9.1 ± 6.6 points). The overall and functional outcome domains of the PROMIS and LD-SRS and the 2-minute walk test (243 ± 107 to 369 ± 151 ft [74 ± 33 to 112 ± 46 m]; p = 0.022) and 6-minute walk test (609 ± 323 to 1,054 ± 555 ft [186 ± 98 to 321 ± 169 m]; p = 0.016) also improved significantly. Serious adverse events included 2 periprosthetic hip fractures, 1 explantation for septic loosening, and 1 explantation for aseptic loosening, with an overall implant retention of 93%. The most common complication was low-grade, soft-tissue infection requiring oral antibiotics.

Conclusions:

Similar to the early experience of other international centers, osseointegration implants improved the overall and functional experience of patients compared with socket prosthetics. Complications were present but manageable and were not a deterrent to ongoing support of the technology.

Level of Evidence:

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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.

The Need to Work Arm in Arm: Calling for Collaboration in Delivering Neuroprosthetic Limb Replacements

Over the last few decades there has been a push to enhance the use of advanced prosthetics within the fields of biomedical engineering, neuroscience, and surgery. Through the development of peripheral neural interfaces and invasive electrodes, an individual's own nervous system can be used to control a prosthesis. With novel improvements in neural recording and signal decoding, this intimate communication has paved the way for bidirectional and intuitive control of prostheses. While various collaborations between engineers and surgeons have led to considerable success with motor control and pain management, it has been significantly more challenging to restore sensation. Many of the existing peripheral neural interfaces have demonstrated success in one of these modalities; however, none are currently able to fully restore limb function. Though this is in part due to the complexity of the human somatosensory system and stability of bioelectronics, the fragmentary and as-yet uncoordinated nature of the neuroprosthetic industry further complicates this advancement. In this review, we provide a comprehensive overview of the current field of neuroprosthetics and explore potential strategies to address its unique challenges. These include exploration of electrodes, surgical techniques, control methods, and prosthetic technology. Additionally, we propose a new approach to optimizing prosthetic limb function and facilitating clinical application by capitalizing on available resources. It is incumbent upon academia and industry to encourage collaboration and utilization of different peripheral neural interfaces in combination with each other to create versatile limbs that not only improve function but quality of life. Despite the rapidly evolving technology, if the field continues to work in divided "silos," we will delay achieving the critical, valuable outcome: creating a prosthetic limb that is right for the patient and positively affects their life.

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.

Osseointegration for Amputees: Current Implants, Techniques, and Future Directions

Osseointegrated prostheses provide a rehabilitation option for amputees offering greater mobility, better satisfaction, and higher use than traditional socket prostheses. There are several different osseointegrated implant designs, surgical techniques, and rehabilitation protocols with their own strengths and limitations. The 2 most prominent risks, infection and periprosthetic fracture, do not seem unacceptably frequent or insurmountable. Proximal amputations or situations leading to reduced mobility are exceptionally infrequent. Osseointegrated implants can be attached to advanced sensory and motor prostheses.

An ex vivo model of medical device-mediated bacterial skin translocation

The skin is a barrier and part of the immune system that protects us from harmful bacteria. Because indwelling medical devices break this barrier, they greatly increase the risk of infection by microbial pathogens. To study how these infections can be prevented through improved clinical practices and medical device technology, it is important to have preclinical models that replicate the early stages of microbial contamination, ingress, and colonization leading up to infection. At present, there are no preclinical ex vivo models specifically developed to simulate conditions for indwelling medical devices. Translocation of pathogens from outside the body across broken skin to normally sterile internal compartments is a rate-limiting step in infectious pathogenesis. In this work, we report a sensitive and reproducible ex vivo porcine skin-catheter model to test how long antimicrobial interventions can delay translocation. Skin preparation was first optimized to minimize tissue damage. The presence of skin dramatically decreased bacterial migration time across the polyurethane catheter interface from > 96 h to 12 h. Using visual colony detection, fluorescence, a luminescent in vitro imaging system, and confocal microscopy, the model was used to quantify time-dependent differences in translocation for eluting and non-eluting antimicrobial catheters. The results show the importance of including tissue in preclinical biofilm models and help to explain current gaps between in vitro testing and clinical outcomes for antimicrobial devices.

Surgical and technological advances in the management of upper limb amputees

Upper limb amputations, ranging from transhumeral to partial hand, can be devastating for patients, their families, and society. Modern paradigm shifts have focused on reconstructive options after upper extremity limb loss, rather than considering the amputation an ablative procedure. Surgical advancements such as targeted muscle reinnervation and regenerative peripheral nerve interface, in combination with technological development of modern prosthetics, have expanded options for patients after amputation. In the near future, advances such as osseointegration, implantable myoelectric sensors, and implantable nerve cuffs may become more widely used and may expand the options for prosthetic integration, myoelectric signal detection, and restoration of sensation. This review summarizes the current advancements in surgical techniques and prosthetics for upper limb amputees. Cite this article: Bone Joint J 2021;103-B(3):430-439.

[Transcutaneous osseointegrated prosthetic systems after major amputation of the lower extremity : A retrospective 3-year analysis]

INTRODUCTION

Transcutaneous osseointegrated prosthetic systems (TOPS) are an established optional procedure for the prosthetic treatment of amputations. Under the term endo-exo-prosthesis (EEP), the endosteal adapted exo-prosthesis (Dr. Grundei®) is currently used as the only standard prosthesis for clinical application in Germany. The prosthetic treatment with EEP involves a two-stage surgical procedure. In a first surgical step, the endo-fixed stem is implanted into the bone; in a second operation, approx. 2-6 weeks later, the skin/soft tissue stoma is created, through which the exoprosthetic components can be coupled transcutaneously.

AIM

The aim of this manuscript was to retrospectively collect descriptive 3‑year statistics (2017-2019) from clinical follow-ups and to analyze them with regard to possible effects of TOPS on the mobility level measured by k‑levels. In addition, a brief description of the current standard of care in Germany regarding TOPS will be given.

METHODS

All patients who underwent EEP after major amputation from February 2017 to December 2019 (n = 72, with 76 implants) were included in this study. The data of the EEP patients were collected in standardized follow-ups. K‑levels were compared preoperatively to 6 months postoperatively.

RESULTS

A total of N = 72 patients (N = 76 implantations) was analyzed in the described period. The main cause of amputations was trauma (68.9%). Main complications were myofascial complaints. Implant loosening and deep infections were observed in two cases (2.7%) during this period. Stoma problems occurred with a 3-year average of 25.7%. In terms of K‑levels, there was a high significant increase from preoperative 1.8 ± 0.8 to 3.0 ± 0.4 after a 6-month period.

CONCLUSION

TOPS is an established optional procedure for the treatment of limb loss. In Germany, only one implant is currently regularly implanted (endo-exo prosthesis), and the restoration is currently focused on the lower limb. The restoration of patients with major amputation of the lower extremity by means of TOPS can lead to an increase in mobility and, thus, to an increase in daily activities and participation in daily living.

A systematic review of health economic evaluations in orthotics and prosthetics: Part 1 - prosthetics

BACKGROUND

The extent to which current prosthetic health economic evaluations inform healthcare policy and investment decisions is unclear. To further the knowledge in this area, existing evidence gaps and method design issues must be identified, thereby informing the design of future research.

OBJECTIVES

The aim of this systematic review was to identify evidence gaps, critical method design and reporting issues and determine the extent to which the literature informs a wide range of policy and investment decisions.

STUDY DESIGN

Systematic review.

METHODS

A range of databases were searched using intervention- and health economic evaluation-related terms. Issues with methodological design and reporting were evaluated using the Consolidated Health Economic Checklist - Extended and the Checklist for Health Economic Evaluation Reporting Standards.

RESULTS

The existing health economic evaluation literature was narrowly focused on informing within-participant component decisions. There were common method design (e.g. time horizon too short) and reporting issues (e.g. competing intervention descriptions) that limit the extent to which this literature can inform policy and investment decisions.

CONCLUSION

There are opportunities to conduct a wider variety of health economic evaluations to support within- and across-sector policy and investment decisions. Changes to aspects of the method design and reporting are encouraged for future research in order to improve the rigour of the health economic evaluation evidence.

CLINICAL RELEVANCE

This systematic review will inform the clinical focus and method design of future prosthetic health economic evaluations. It will also guide readers and policy-makers in their interpretation of the current literature and their understanding of the extent to which the current literature can be used to inform policy and investment decisions.

Printing the Pathway Forward in Bone Metastatic Cancer Research: Applications of 3D Engineered Models and Bioprinted Scaffolds to Recapitulate the Bone-Tumor Niche

Breast cancer commonly metastasizes to bone, resulting in osteolytic lesions and poor patient quality of life. The bone extracellular matrix (ECM) plays a critical role in cancer cell metastasis by means of the physical and biochemical cues it provides to support cellular crosstalk. Current two-dimensional in-vitro models lack the spatial and biochemical complexities of the native ECM and do not fully recapitulate crosstalk that occurs between the tumor and endogenous stromal cells. Engineered models such as bone-on-a-chip, extramedullary bone, and bioreactors are presently used to model cellular crosstalk and bone-tumor cell interactions, but fall short of providing a bone-biomimetic microenvironment. Three-dimensional bioprinting allows for the deposition of biocompatible materials and living cells in complex architectures, as well as provides a means to better replicate biological tissue niches in-vitro. In cancer research specifically, 3D constructs have been instrumental in seminal work modeling cancer cell dissemination to bone and bone-tumor cell crosstalk in the skeleton. Furthermore, the use of biocompatible materials, such as hydroxyapatite, allows for printing of bone-like microenvironments with the ability to be implanted and studied in in-vivo animal models. Moreover, the use of bioprinted models could drive the development of novel cancer therapies and drug delivery vehicles.

Osseointegration of Extremity Prostheses: A Primer for the Plastic Surgeon

Interest in amputation surgery has increased in conjunction with rising public awareness about amputee care. To date, plastic surgeons have impacted the quality of life and functional potential of amputees through novel strategies for sensory feedback and prosthesis control and various techniques for neuroma treatment and prevention. Osseointegration, which involves the direct skeletal attachment of a prosthesis to bone, has the ability to further maximize amputee function. There exists a critical role for plastic surgeons to help optimize techniques for extremity osseointegration through improved wound care and soft-tissue management. An overview of current osseointegrated prostheses and their associated limitations, and potential avenues through which plastic surgeons can help mitigate these challenges, are discussed in this article.

Advanced techniques in amputation surgery and prosthetic technology in the lower extremity

Bone-anchored implants give patients with unmanageable stump problems hope for drastic improvements in function and quality of life and are therefore increasingly considered a viable solution for lower-limb amputees and their orthopaedic surgeons, despite high infection rates.Regarding diversity and increasing numbers of implants worldwide, efforts are to be supported to arrange an international bone-anchored implant register to transparently overview pros and cons.Due to few, but high-quality, articles about the beneficial effects of targeted muscle innervation (TMR) and regenerative peripheral nerve interface (RPNI), these surgical techniques ought to be directly transferred into clinical protocols, observations and routines.Bionics of the lower extremity is an emerging cutting-edge technology. The main goal lies in the reduction of recognition and classification errors in changes of ambulant modes. Agonist-antagonist myoneuronal interfaces may be a most promising start in controlling of actively powered ankle joints.As advanced amputation surgical techniques are becoming part of clinical routine, the development of financing strategies besides medical strategies ought to be boosted, leading to cutting-edge technology at an affordable price.Microprocessor-controlled components are broadly available, and amputees do see benefits. Devices from different manufacturers differ in gait kinematics with huge inter-individual varieties between amputees that cannot be explained by age. Active microprocessor-controlled knees/ankles (A-MPK/As) might succeed in uneven ground-walking. Patients ought to be supported to receive appropriate prosthetic components to reach their everyday goals in a desirable way.Increased funding of research in the field of prosthetic technology could enhance more high-quality research in order to generate a high level of evidence and to identify individuals who can profit most from microprocessor-controlled prosthetic components. Cite this article: EFORT Open Rev 2020;5:724-741. DOI: 10.1302/2058-5241.5.190070.

Osseointegrated reconstruction and rehabilitation of transtibial amputees: the Osseointegration Group of Australia surgical technique and protocol for a prospective cohort study

INTRODUCTION

Lower extremity amputation uniformly impairs a person's vocational, social and recreational capacity. Rehabilitation in traditional socket prostheses (TSP) is associated with a spectrum of complications involving the socket-residuum interface which lead to reduced prosthetic use and quality of life. Osseointegration has recently emerged as a novel concept to overcome these complications by eliminating this interface and anchoring the prosthesis directly to bone. Though the complications of TSPs affect both transfemoral and transtibial amputees, Osseointegration has been predominantly performed in transfemoral ones assuming a greater benefit/risk ratio. However, as the safety of the procedure has been established, we intend to extend the concept to transtibial amputees and document the outcomes.

METHODS AND ANALYSIS

This is protocol for a prospective cohort study, with patient enrolment started in 2014 and expected to be completed by 2022. The inclusion criteria are age over 18 years, unilateral, bilateral and mixed transtibial amputation and experiencing socket-related problems. All patients receive osseointegrated implants, the type of which depend on the length of the residuum and quality of bone, which are press-fitted into the residual bone. Objective functional outcomes comprising 6-Minute Walk Test, Timed Up-and-Go test and K-level, subjective patient-reported-quality-of-life outcomes (Short Form Health Survey 36, daily prosthetic wear hours, prosthetic wear satisfaction) and adverse events are recorded preoperatively and at postoperative follow-up intervals of 3, 6, 12 months and yearly, and compared with the preoperative values using appropriate statistical tests. Multivariable multilevel logistic regression will be performed with a focus to identify factors associated with outcomes and adverse events, specifically infection, periprosthetic fracture, implant fracture and aseptic loosening.

ETHICS AND DISSEMINATION

The Ethics approval for the study has been received from the University of Notre Dame, Sydney, Australia (014153S). The outcomes of this study will be disseminated by publications in peer-reviewed academic journals and scientific presentations at relevant orthopaedic conferences.

Transkutane osseointegrierte Prothesensysteme (TOPS) zur Versorgung Oberschenkelamputierter

Ziel Der Studie Durchgeführt wurde eine retrospektive Analyse der klinischen Ergebnisse und Komplikationsraten aller oberschenkelamputierten Patienten eines Zentrums, die mit dem neuesten Implantatdesign der sogenannten Endo-Exo-Femur-Prothese (EEFP, dritte Generation) versorgt wurden. Ziel ist es, spezifische Informationen zu Langzeitkomplikationen dieser Amputationsversorgungsform zu gewinnen.

Methodik Im Januar 2019 wurden Daten aller Oberschenkelamputierten, die von 2010 bis 2016 an einer Akutklinik aus Schleswig-Holstein mit TOPS versorgt wurden, retrospektiv analysiert. Dies geschah unter besonderer Berücksichtigung der postoperativen Komplikationen. Hierfür wurden alle Untersuchungsbefunde der klinischen Routine-Nachsorge-Untersuchungen herangezogen. Die Komplikationen wurden unterteilt in Stomaprobleme, orthopädie-technische Probleme, Frakturen und Explantationen. Alle EEFPs besaßen das gleiche Implantatdesign (dritte Generation). Dieses Implantat findet derzeit als einziges TOPS in Deutschland klinische Anwendung. Eine deskriptive Statistik des Patientenkollektivs, sowie Verhältnisangaben über aufgetretene Komplikationen wurden berechnet.

Ergebnisse Insgesamt wurden in diesem Zeitraum 68 Implantationen durchgeführt. Durchschnittliche Beobachtungszeit war 6,32 Jahre (±2,16 Jahre). Das mittlere Alter der Patienten betrug 51,84 Jahre±12,12 Jahre. Ursache der Amputation waren überwiegend Traumata (82,35%). Stoma-assoziierte Probleme zeigten mit 7% die höchste Inzidenz innerhalb aller beobachteten, patientenassoziierten Komplikationen und stellten die größten Herausforderungen während des Rehabilitationsprozesses dar. Betrachtet man nur die chirurgischen Komplikationen, so hatten 81% überhaupt keine Komplikationen. Insgesamt wiesen 15% orthopädie-technische Probleme auf, 6% eine peri-prothetische Fraktur, 7% Probleme am Stoma und 3% mussten aufgrund einer Infektion explantiert werden.

Schlussfolgerung Die erhobene Datenanalyse zeigt, dass TOPS (hier die EEFP der dritten Generation) eine erfolgreiche alternative Behandlungsmethode zur Schaftprothesenversorgung für Patienten mit Oberschenkelknochenverlust darstellen können. Die Indikation sollte erst nach dem Versagen einer Schaftversorgung erfolgen und Kontraindikationen müssen umfassend ausgeschlossen werden. Die größten Herausforderungen im Rehabilitationsprozess stellen die Vermeidung von Stomakomplikationen, Infektionen und orthopädie-technischen Problemen dar. Die Rehabilitation von Amputierten, die mit TOPS behandelt werden, erfordert daher ein interdisziplinäres, spezialisiertes Rehabilitations-Team und eine lebenslange rehabilitative Versorgung.

Orthopaedic osseointegration: Implantology and future directions

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

Soft Tissue Contouring at the Time of Osseointegrated Implant Reconstruction for Lower Extremity Amputation

INTRODUCTION

Patients with lower extremity amputations using a classic socket prosthesis face many challenges related to the socket-limb interface. The adaptation of osseointegration has allowed for the attachment of a prosthesis directly to bone, eliminating this interface and providing mechanical benefits. Contrary to the socket prosthesis, the osseointegrated prosthesis requires reducing and minimizing the soft tissue envelope. Studies have shown that patients who have undergone placement of these implants have high rates of reoperation for soft tissue redundancy. The purpose of our study was to evaluate complication rates and need for revisional surgery using our technique of soft tissue closure around the prosthesis at the time of implant placement.

METHODS

An institutional review board-approved, retrospective chart review was performed on all patients who underwent implantation of an osseointegrated prosthesis for lower extremity amputation with concomitant plastic surgery closure at our institution during a 2-year period from June 2017 to June 2019. Patient demographics, health status descriptors, operative data, length of admission, and rates of postoperative complications were gathered from the electronic medical record and coded into a HIPAA-compliant database. Specific outcomes tracked included minor and major infection, osteomyelitis, implant failure, hematoma, seroma, delayed wound healing, and rates of reoperation and readmission.

RESULTS

There were a total of 14 patients who underwent osseointegrated implant placement with concomitant plastic surgical coverage of the prosthesis during the study period. The average patient age was 50 years (range, 26-70 years), and average body mass index was 32.2 kg/m (range, 19.7-44.8 kg/m). Average follow-up time was 28 weeks (range, 10-73 weeks). There were 2 cases of local infection resolved with a course of oral antibiotics. There were no instances of infection requiring procedural intervention or hospital admission, nor any cases of osteomyelitis. Two patients required outpatient surgery for exchange of implant abutment, one required revision of a prosthesis for hardware loosening, and one required targeted muscle reinnervation of a sciatic nerve neuroma. There were no patients who required revisional surgery for soft tissue redundancy and no cases of delayed wound healing.

CONCLUSIONS

Adequate planning of incisions and soft tissue contouring is important in the care of osseointegrated patients. Plastic surgery involvement can decrease soft tissue complications and lead to improved patient outcomes.

The future of the amputees with osseointegration: A systematic review of literature

OBJECTIVE

Socket prosthesis attachment is the current gold standard for limb amputees. Osseointegrated implantation is a novel technique that has many proposed advantages over the current gold standard. Clear advantages for its use over socket prosthetic attachment has been well established in literature. It decreases socket problems as pinching, pressure points, chronic skin problems and frequent socket change due to atrophy of muscles.

METHODS

We reviewed primary research articles documenting complication rates and outcome measures in patients with osseointegrated prosthesis implantation after limb amputation.

RESULTS

Nine studies were identified with a total of 211-242 patients. Clinical, radiographic, and functional outcomes, as well as complications were considered. The mean duration of follow-up was greater than 12 months in all studies.

CONCLUSIONS

Osseointegration is an effective alternative to socket prosthesis in transfemoral amputees. Transtibial and upper extremity implants are underreported in the literature and clear indication for their effectiveness over socket prosthesis does not exist. Minor complications are most common, such as soft tissue infections, and may be mitigated in the future by improvements in surgical technique and implant design.The level of evidence is 3.

A 15-year follow-up of transfemoral amputees with bone-anchored transcutaneous prostheses

AIMS

The aim of this study was to describe implant and patient-reported outcome in patients with a unilateral transfemoral amputation (TFA) treated with a bone-anchored, transcutaneous prosthesis.

METHODS

In this cohort study, all patients with a unilateral TFA treated with the Osseointegrated Prostheses for the Rehabilitation of Amputees (OPRA) implant system in Sahlgrenska University Hospital, Gothenburg, Sweden, between January 1999 and December 2017 were included. The cohort comprised 111 patients (78 male (70%)), with a mean age 45 years (17 to 70). The main reason for amputation was trauma in 75 (68%) and tumours in 23 (21%). Patients answered the Questionnaire for Persons with Transfemoral Amputation (Q-TFA) before treatment and at two, five, seven, ten, and 15 years' follow-up. A prosthetic activity grade was assigned to each patient at each timepoint. All mechanical complications, defined as fracture, bending, or wear to any part of the implant system resulting in removal or change, were recorded.

RESULTS

The Q-TFA scores at two, five, seven, and ten years showed significantly more prosthetic use, better mobility, fewer problems, and an improved global situation, compared with baseline. The survival rate of the osseointegrated implant part (the fixture) was 89% and 72% after seven and 15 years, respectively. A total of 61 patients (55%) had mechanical complications (mean 3.3 (SD 5.76)), resulting in exchange of the percutaneous implant parts. There was a positive relationship between a higher activity grade and the number of mechanical complications.

CONCLUSION

Compared with before treatment, the patient-reported outcome was significantly better and remained so over time. Although osseointegration and the ability to transfer loads over a 15-year period have been demonstrated, a large number of mechanical failures in the external implant parts were found. Since these were related to higher activity, restrictions in activity and improvements to the mechanical properties of the implant system are required. Cite this article: Bone Joint J 2020;102-B(1):55-63.

Osseointegrated Prosthetic Implants for People With Lower-Limb Amputation: A Health Technology Assessment

BACKGROUND

Osseointegrated prosthetic implants are biocompatible metal devices that are inserted into the residual bone to integrate with the bone and attach to the external prosthesis, eliminating the need for socket prostheses and the problems that may accompany their use. We conducted a health technology assessment of osseointegrated prosthetic implants, compared with conventional socket prostheses, for people with lower-limb amputation who experience chronic problems with their prosthetic socket, leading to prosthesis intolerance and reduced mobility. Our analysis included an evaluation of effectiveness, safety, cost-effectiveness, the budget impact of publicly funding osseointegrated prosthetic implants, and patient preferences and values.

METHODS

We performed a systematic literature search of the clinical evidence on the safety and effectiveness of the latest iterations of three implant systems: the Osseointegrated Prostheses for the Rehabilitation of Amputees (OPRA) Implant System, the Endo-Exo-Femur-Prosthesis, and the Osseointegration Group of Australia-Osseointegration Prosthetic Limb (OGAP-OPL). We assessed the risk of bias of individual studies and determined the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted a cost-utility analysis with a lifetime horizon from a public payer perspective. We also analyzed the net budget impact of publicly funding osseointegrated prosthetic implants in Ontario. To contextualize the potential value of osseointegrated prosthetic implants, we spoke with people with lower-limb amputations.

RESULTS

We included nine studies in the clinical evidence review. All studies included patients with above-the-knee amputation who underwent two-stage surgery and mostly had short-term follow-up. With osseointegrated prosthetic implants, scores for functional outcomes improved significantly as measured by 6-Minute Walk Test (6MWT), Timed Up and Go (TUG) test, and Questionnaire for Persons with a Transfemoral Amputation (Q-TFA). The scores for quality of life measured by SF-36 showed significant improvement in the physical component summary but a nonsignificant decline for the mental component summary. The most frequently seen adverse event was superficial infection, occurring in about half of patients in some studies. Deep or bone infection was a serious adverse event, with variable rates among the studies depending on the length of follow-up. The treatment of deep or bone infection required long-term antibiotic use, surgical debridement, revision surgery, and implant extraction in some cases. Other adverse events included femoral bone fracture, implant breakage, issues with extramedullary parts that required replacement, and implant removal. Our assessment of the quality of the clinical evidence according to the GRADE criteria found low certainty in terms of improvement in functional outcomes, low certainty for quality of life, and high certainty of an increase in adverse events; all findings compared receiving an osseointegrated prosthetic implant with not receiving an osseointegrated prosthetic implant.In our economic model, osseointegrated prosthetic implants were found to be more effective and more expensive than having people remain users of an uncomfortable socket prosthesis. Our best estimate of the incremental cost-effectiveness ratio (ICER) for osseointegration, compared with an uncomfortable socket, was $94,987 per quality-adjusted life-year (QALY) gained. The probability of osseointegration being cost-effective was 54.2% at a willingness-to-pay value of $100,000 per QALY gained. The annual net budget impact of publicly funding osseointegrated prosthetic implants in Ontario over the next 5 years, for a small population of eligible candidates, would range from $1.5 million in year 1 to $0.6 million in year 5, for a 5-year total of $5.3 million.We interviewed 13 people with a lower-limb amputation; nine had experience with both a conventional socket prosthesis and an osseointegrated prosthetic implant, three had experience with a conventional socket prosthesis only, and one had only recently undergone amputation and had not yet chosen a prosthesis. People who had received an osseointegrated prosthetic implant said they had better mobility and quality of life than before receiving this implant but had concerns about the ongoing risk of infection and potential for problems with implant maintenance. People using a conventional socket prosthesis said cost was the only factor preventing them from undergoing an osseointegration procedure.

CONCLUSIONS

In the studies included in the clinical evidence review, most people who received osseointegrated prosthetic implants were followed for only a few years. Studies showed that functional outcomes and physical ability improved with osseointegrated prosthetic implants (GRADE: Low), but there was uncertainty about the impact of these implants on people's emotional health (GRADE: Low). Osseointegrated prosthetic implants can lead to serious adverse events such as bone infection and bone fracture in some patients, which may require additional surgeries (GRADE: High). The reference case of the primary economic evaluation represented a conservative estimate of cost-effectiveness and found osseointegration may be cost-effective, but there is a large degree of uncertainty given parameter uncertainty and the need to use proxy costs. Scenario analyses explored potential variations in approaches to modelling and parameter selection. Qualitative interviews with people with a lower-limb amputation and caregivers underscored the challenges of conventional socket prostheses, but cost remains an important barrier to pursuing osseointegrated prosthetic implantation.

Analysis of the Stomal Microbiota of a Percutaneous Osseointegrated Prosthesis: A Longitudinal Prospective Cohort Study

Percutaneous osseointegrated (OI) prostheses (POPs) are used to skeletally attach artificial limbs in amputees. While any permanent percutaneous interface is at risk of becoming infected by the resident microbiota colonizing the stoma, most of these patients remain infection-free. Avoidance of infection likely depends upon a mechanically and/or biologically stable skin-to-implant interface. The ultimate question remains, "why do some stomata become infected while others do not?" The answer might be found in the dynamic bacterial communities of the patient and within the stomal site itself. This study is an appendix to the first Food and Drug Administration approved prospective early feasibility study of OI prosthetic docking, in which, 10 transfemoral amputees were implanted with a unique POP device. In this analytical, longitudinal cohort study, each patient's skin and stomal microbiota were analyzed from the initial surgery to 1 year following the second-stage surgery. During each follow-up visit, three swab samples-stomal, device thigh skin and contralateral thigh skin-were obtained. DNA was extracted, and bacterial 16S ribosomal RNA (rRNA) genes were amplified and sequenced to profile microbial communities. The stomal microbiota were distinct from the microbiota on the adjacent thigh skin and the skin of the contralateral thigh, with a significantly increased abundance of Staphylococcus aureus within the stoma. Early on stomal microbiota were characterized by high diversity and high relative abundance of obligate anaerobes. Over time, the stomal microbiota shifted and stabilized in communities of lower diversity dominated by Streptococcus, Corynebacterium, and/or Staphylococcus spp. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2645-2654, 2019.

Orthopaedic Osseointegration: State of the Art

Osseointegration is a surgical approach that permitted the direct attachment of an external prosthesis to the skeleton in some select patients with amputation, who had failed to tolerate conventional sockets, thereby obviating related issues such as discomfort, skin breakdown, and poor fit. In this specific population, osseointegration offers the potential for enhanced biomechanical advantage and rehabilitative potential. Multiple percutaneous implant systems exist for clinical use internationally, each attempting to create a stable bone-implant interface while avoiding complications such as infection and loosening. Prospective clinical trials are now underway in the United States. This article will review the history and biology of osseointegration, indications and contraindications for use of currently available implant systems, and reported outcomes. Future directions of orthopaedic osseointegration technology, including electronic systems capable of biomimetic bidirectional volitional motor control of, and sensory/proprioceptive feedback from, external prosthetic devices, will also be discussed.

Survey data on the quality of life of consumers fitted with osseointegrated fixation and bone-anchored limb prostheses provided by government organization

The data in this paper are related to the research article entitled “Development of a government continuous quality improvement procedure for assessing the provision of bone anchored limb prosthesis: A process re-design descriptive study” (Frossard et al., Canadian Prosthetics & Orthotics Journal, 2018. 1(2). p. 1–14). This article contains quality of life data experienced by individuals before and after implantation of a press-fit or screw-type osseointegrated fixation when fitted with conventional socket-suspended and bone-anchored limb prosthesis, respectively. This specifically-designed survey was developed and administered by Queensland Artificial Limb Services (QALS), an Australian State government organization. It was an integrated part of QALS′ continuous quality improvement procedure for assessing the provision of bone-anchored prosthesis. A total of 12 out of the 65 consumers completed to the survey, giving a return rate of 18%. This benchmark information can contribute to inform the design of (A) other patients' experience surveys including those built-in governmental continuous quality improvement procedure as well as (B) clinical trials looking at the overall effects of surgical implantation of ossoeintegrated fixation on patients' quality of life. Online repository contains the files: https://data.mendeley.com/datasets/bkbxxmrhfh/1.