Percutaneous EndoProsthetic Osseointegration for Limbs (PEPOL) facilitates improved quality of life (QOL) and objective mobility for most amputee's discontent with their traditional socket prosthesis (TSP) experience. Some amputees desiring PEPOL have residual bone much shorter than the currently marketed press-fit implant lengths of 14-16 cm, potentially a risk for failure to integrate. We report on the techniques used, complications experienced, the management of those complications, and the overall mobility outcomes of seven patients who had femur distraction osteogenesis (DO) with a Freedom nail followed by PEPOL. Retrospective evaluation of a prospectively maintained database identified nine patients (5 females) who had transfemoral DO in preparation for PEPOL with two years of follow-up after PEPOL. Six patients had traumatic causes of amputation, one had perinatal complications, one was performed to manage necrotizing fasciitis and one was performed as a result of osteosarcoma. The residual femurs on average started at 102.2±39.7 mm and were lengthened 58.1±20.7 mm, 98±45% of goal (99±161% of the original bone length). Five patients (56%) had a complication requiring additional surgery. At a mean of 3.4±0.6 (2.6-4.4) years following osseointegration six patients had K-level >2. The 6 Minute Walk Test remained unchanged (267±56 vs 308 ± 117 meters). Patient self-rating of prosthesis function, problems, and amputee situation did not significantly change from before DO to after osseointegration. Six patients required additional surgery following osseointegration: six to remove fixation plates placed to maintain distraction osteogenesis length at osseointegration; two required irritation and debridement for infection. Extremely short residual femurs which make TSP use troublesome can be lengthening with externally controlled telescoping nails, and successfully achieve osseointegration. However, it is imperative to counsel patients that additional surgery to address inadequate regenerate or to remove painful hardware used to maintain fixation may be necessary. This may improve the amputee's expectations before beginning on a potentially arduous process

Introduction. Percutaneous EndoProsthetic Osseointegration for Limbs (PEPOL) facilitates improved quality of life (QOL) and objective mobility for most amputees discontent with their traditional socket prosthesis (TSP) experience. Some amputees desiring PEPOL have residual bone much shorter than the currently marketed press-fit implant lengths of 14–16 cm, potentially a risk for failure to integrate. We report on the techniques used, complications experienced, the management of those complications, and the overall mobility outcomes of seven patients who had femur distraction osteogenesis (DO) with a Freedom nail followed by PEPOL. Materials & Methods. Retrospective evaluation of a prospectively maintained database identified nine patients (5 females) who had transfemoral DO in preparation for PEPOL with two years of follow-up after PEPOL. Six patients had traumatic causes of amputation, one had perinatal complications, one was performed to manage necrotizing fasciitis and one was performed as a result of osteosarcoma. Results. The average age at which DO commenced was 39.4±15.9 years, and seven patients had their amputation more than ten years prior (average 25.5±18.8 years). The residual femurs on average started at 102.2±39.7 mm and were lengthened 58.1±20.7 mm, 98±45% of goal (99±161% of the original bone length). Five patients (56%) had a complication requiring additional surgery: four events of inadequate regenerate were managed with continued lengthening to desired goal followed by autograft placement harvested from contralateral femur reaming; one patient had the cerclage wires break which required operative replacement. All patients had osseointegration performed, at 355±123 days after the initial lengthening nail surgery. One patient had K-level >2 before DO, at a mean of 3.4±0.6 (2.6–4.4) years following osseointegration six patients had K-level >2. The 6 Minute Walk Test remained unchanged (267±56 vs 308 ± 117 meters). Patient self-rating of prosthesis function, problems, and amputee situation did not significantly change from before DO to after osseointegration. Six patients required additional surgery following osseointegration: six to remove fixation plates placed to maintain distraction osteogenesis length at osseointegration; two required irritation and debridement for infection. Conclusions. Extremely short residual femurs which make TSP use troublesome can be lengthening with externally controlled telescoping nails, and successfully achieve osseointegration. However, it is imperative to counsel patients that additional surgery to address inadequate regenerate or to remove painful hardware used to maintain fixation may be necessary. This may improve the amputee's expectations before beginning on a potentially arduous process

Electron Microscopy and Synchrotron analysis of Heterotopic Ossification (HO) from blast-related amputees' has shown that HO is bone with a disorganised structure and altered remodelling. This research performs mechanical testing of HO to understand its biomechanical properties in an attempt to create an accurate model to predict its morphological appearance. The hypothesis of this work is that HO is mechanically mediated in its formation. Synchrotron mechanical analysis of HO samples was performed to measure Young's modulus, ultimate strength and density distribution. A novel algorithm based on Wolf's law was implemented in a Finite Element (FE) analysis model of HO to take into account the differing mechanical and biological properties measured and the presence of HO outside the skeletal system. An HO modeling factor, which considers boundary conditions, and regulates recruitment of the soft tissue into bone formation, results in a re-creatable formation of HO within the soft tissues, comparable to the appearance of HO seen in military amputees. The results and model demonstrates that certain types of HO are under the control of endogenous and exogenous mechanical stimulus. HO can thus be mechanically exploited in the casualty management and rehabilitation process to achieve better clinical outcomes

Introduction. In the US over half a million people are prescribed crutches each year. More than 750,000 wheelchair users exist in the UK and wheelchair and crutch users commonly develop shoulder pathology. The purpose of this study was to determine the influence of complex topographies on heart rate (HR) and thus energy expenditure, using a wheelchair and differing crutch designs on the exertional body stress. Method. Two Paralympics Athletes from the GB amputee football squad were assessed in a Lomax Active wheelchair and 5 different types of crutches in a randomly allocated order over a course representing everyday complex terrains at the Pedestrian Accessibility and Movement Environment Laboratory (PAMELA), University College London. In addition results were compared over the same course with the athletes using their own personal pair of crutches. The PAMELA course consisted of a mixture of 4% and 2.5% cross falls (transverse) and a simulated road crossing, sprint, slalom and a slow straight. Results. Initial findings show both athletes needed to work harder, thus spend more energy (13% more) to cope with the wheelchair tasks (2.6) than with the crutches(2.3). The Total Heart Beat Index (THBI) revealed that trying to ambulate with the crutches was more difficult in 4% cross fall (3.3) than on the longitudinal slopes (3.2), followed by 2.5% cross fall (2.85), slalom (2.1) and sprint (1.8). For the same tasks executed using a wheelchair the 2.5% gradient was shown to be the higher energy demanding (3.8), followed by the 4% (3.5), slopes (2.9), slalom (2.2) and sprint (2.1). Both participants reached a lower THBI (2.2) during the same task when using their own crutches. Conclusion. The results of this study imply that ambulation with crutches puts less burden than wheelchair. This might be due to the time these athletes spend with crutches, either in training or activities of daily living. Furthermore, the physical strain which they underwent during the complex terrains was clearly reflected on their heart rate. The setting of longer distances to collect more consistent HR data should be the focus of further research. The comparison in performance between athletes and the general population should also be investigated

This work examines the Upper limb (UL) blast-mediated traumatic amputation (TA) significance from recent operations in Afghanistan. It is hypothesized that the presence of an UL amputation at any level is an independent predictor of torso injury.

A joint theatre trauma registry search was performed to determine the number of British casualties with TA and their associated injuries.

UL TA accounted for 15.7% of all amputations; distributed: shoulder disarticulation 2.5%, trans-humeral 30%, elbow disarticulation 10%, trans-radial 20% and hand 37.5%. The presence of an UL amputation was more likely in dismounted casualties (P=0.015) and is a predictor of an increased number of total body regions injured and thoracic injuries (P 0.001 and P 0.026 respectively). An increased Injury Severity Score (ISS) was seen in patients with multiple amputations involving the UL (UL TA present ISS=30, no UL TA ISS=21; P=0.000) and the ISS was not significantly different whether mounted or dismounted (P=0.806).

The presence of an upper limb amputation at any level should insight in the receiving clinician a high index of suspicion of concomitant internal injury; especially thoracic injury. Therefore with regards to blast mediated TA the injury patterns observed reflect a primary and tertiary blast mechanism of injury.

Traditional socket prosthesis (TSP) rehabilitation for amputees is associated with substantial dissatisfaction due to poor mobility and pain from soft tissue squeezing. Osseointegration (OI), eliminates skin compression and prosthesis fit issues, providing superior mobility and quality of life (QOL) for most amputees. The potential for OI to benefit patients with exceptionally poor mobility is understudied. To address this knowledge gap, this project investigated the mobility and QOL changes. A retrospective review was performed to identify transfemoral amputees who presented with wheelchair-bound mobility (K0) and had at least five years of post-osseointegration follow-up. Outcome measures included changes in mobility (K-level, daily prosthesis wear hours, Timed Up and Go (TUG), 6 minute walk test (6MWT)) and QOL (Questionnaire for persons with a Transfemoral Amputation (QTFA); Short Form Health Survey 36 (SF36). Adverse events recorded included debridement for infection, implant revision surgery, fractures, and implant failures. 9 patients with mean age 48.2±7.7 (range 34-59) years were included. The proportion of patients achieving K-level >2 improved from 0/9=0% to [9/9=100%], p<0.001. The 6MWT improved from 0±0 to 320.65±57 meters (p<0.001). The TUG improved from incapable to 10.68±2.7 seconds (p<0.001). Statistically significant QOL metrics included QTFA global score (33.33±31 vs 68.52±21, p=0.039), SF36 physical component score (30.03±6.3 vs 42.34±12, p=0.023) and the SF36 mental component score (47.89±8.8 vs 51.95±10.4, p=0.332). Six patients required operative intervention to address complications. Five developed infections: three had debridement, and 2 required implant removal and reimplantation. Osseointegration does confer significant sustained mobility and quality of life improvement for wheelchair bound transfemoral amputees. All 9 K0 patients had statistically improved mobility and QOL after osseointegrated reconstruction. This supports osseointegration as an effective rapid and long-term rehabilitation alternative for patients who have the neurologic and muscular capacity to walk but are unable due to issues related to their TSP

Introduction. Transfemoral osseointegration (TFOI) for amputees has substantial literature proving superior quality of life and mobility versus a socketed prosthesis. Some amputees have hip arthritis that would be relieved by a total hip replacement (THR). No other group has reported performing a THR in association with TFOI (THR+TFOI). We report the outcomes of eight patients who had THR+TFOI, followed for an average 5.2 years. Materials & Methods. Our osseointegration registry was retrospectively reviewed to identify all patients who had TFOI and also had THR, performed at least two years prior. Six patients had TFOI then THR, one simultaneous, one THR then TFOI. All constructs were in continuity from hip to prosthetic limb. Outcomes were: complications prompting surgical intervention, and changes in subjective hip pain, K-level, daily prosthesis wear hours, Questionnaire for Persons with a Transfemoral Amputation (QTFA), and Short Form 36 (SF36). All patients had clinical follow-up, but one patient did not have complete mobility and quality of life survey data at both time periods. Results. Four (50%) were male, average age 52.7±14.8 years. Three patients (38%) had amputation for trauma, three for osteosarcoma, one each (13%) infected total knee and persistent infection after deformity surgery. One patient died one year after THR+TOFA from subsequently diagnosed pancreatic cancer. One patient had superficial debridement for infection with implant retention after five years. No implants were removed, no fractures occurred. All patients reported severe hip pain preoperatively versus full relief of hip pain afterwards. K-level improved from 0/8=0% K>2 (six were wheelchair-bound) to 5/8=63% (p=.026). At least 8 hours of prosthesis wear was reported by 2/7=29% before TOFA vs 5/7=71% after (p=.286). The QTFA improved in all categories, but not significantly: Global (40.0±21.6 vs 60.0±10.9, p=.136), Problem (50.2±33.2 vs 15.4±8.4, p=.079), and Mobility (35.9±26.8 vs 58.3±30.7, p=.150). The SF36 also improved minimally and not significantly: Mental (53.6±12.0 vs 54.7±4.6, p=.849) and Physical (32.5±10.9 vs 36.3±11.2, p=.634). Conclusions. THR+TFOI is a successful reconstruction option for amputees who desire relief from severe pain related to hip joint degeneration, and also the opportunity for improved mobility and quality of life that TFOI typically confers. In our cohort, the procedure proved safe: no associated deaths, no removals, one soft tissue debridement. Mobility improved markedly. Quality of life improved, but not to significant thresholds as measured by the surveys. THR+TFOI appears safe and reasonable to offer to transfemoral amputees with painful hip joint degeneration

Introduction. Transtibial osseointegration (TFOI) for amputees has limited but clear literature identifying superior quality of life and mobility versus a socketed prosthesis. Some amputees have knee arthritis that would be relieved by a total knee replacement (TKR). No other group has reported performing a TKR in association with TTOI (TKR+TTOI). We report the outcomes of nine patients who had TKR+TTOI, followed for an average 6.5 years. Materials & Methods. Our osseointegration registry was retrospectively reviewed to identify all patients who had TTOI and who also had TKR, performed at least two years prior. Four patients had TKR first the TTOI, four patients had simultaneous TKR+TTOI, and one patient had 1 OI first then TKR. All constructs were in continuity from hinged TKR to the prosthetic limb. Outcomes were: complications prompting surgical intervention, and changes in daily prosthesis wear hours, Questionnaire for Persons with a Transfemoral Amputation (QTFA), and Short Form 36 (SF36). All patients had clinical follow-up, but two patients did not have complete survey and mobility tests at both time periods. Results. Six (67%) were male, average age 51.2±14.7 years. All primary amputations were performed to manage traumatic injury or its sequelae. No patients died. Five patients (56%) developed infection leading to eventual transfemoral amputation 36.0±15.3 months later, and 1 patient had a single debridement six years after TTOI with no additional surgery in the subsequent two years. All patients who had transfemoral amputation elected for and received transfemoral osseointegration, and no infections occurred, although one patient sustained a periprosthetic fracture which was managed with internal fixation and implant retention and walks independently. The proportion of patients who wore their prosthesis at least 8 hours daily was 5/9=56%, versus 7/9=78% (p=.620). Even after proximal level amputation, the QTFA scores improved versus prior to TKR+TTOI, although not significantly: Global (45.2±20.3 vs 66.7±27.6, p=.179), Problem (39.8±19.8 vs 21.5±16.8, p=.205), Mobility (54.8±28.1 vs 67.7±25.0, p=.356). SF36 changes were also non-significant: Mental (58.6±7.0 vs 46.1±11.0, p=.068), Physical (34.3±6.1 vs 35.2±13.7, p=.904). Conclusions. TKR+TTOI presents a high risk for eventual infection prompting subsequent transfemoral amputation. Although none of these patients died, in general, TKR infection can lead to patient mortality. Given the exceptional benefit to preserving the knee joint to preserve amputee mobility and quality of life, it would be devastating to flatly force transtibial amputees with severe degenerative knee joint pain and unable to use a socket prosthesis to choose between TTOI but a painful knee, or preemptive transfemoral amputation for transfemoral osseointegration. Therefore, TTOI for patients who also request TKR must be considered cautiously. Given that this frequency of infection does not occur in patients who have total hip replacement in association with transfemoral osseointegration, the underlying issue may not be that linked joint replacement with osseointegrated limb replacement is incompatible, but may require further consideration of biological barriers to ascending infection and/or significant changes to implant design, surgical technique, or other yet-uncertain factors

Introduction. This study reports on minimum 2 year follow up outcomes on functional and quality of life of patients after undergoing bilateral osseointegration in comparison to traditional socket prosthesis. Materials & Methods. This is a prospective pilot study of 35 patients, consisting of 30 males and 5 females, aged 22–66 (mean 36) years at surgery, with minimum two-year follow-up. Selection criteria were age over 18 years, bilateral amputees who had socket-related problems or were wheelchair-bound with short stumps and non-reconstructable limb pathology. Principle outcome measures included the Questionnaire for persons with a Trans-Femoral Amputation (Q-TFA), Short Form Health Survey 36 (SF-36), Six Minute Walk Test (6MWT), Timed Up and Go (TUG), and K-levels. Adverse events were recorded including infection, revision surgery, fractures, and implant failures. Results. Comparisons were made using differences between the mean pre-operative and mean post-operative values for each outcome measure. Significant improvements in all validated outcome measures were observed. All patient who were wheelchair bound prior to the surgery were able to mobilise post operatively. The occurrence levels of adverse events, including the infection rate and revision rate within this patient cohort, were similar to other established trans-femoral osseointegration studies. Conclusions. These preliminary results indicate that osseointegration surgery is a safe and effective alternative treatment for bilateral amputees experiencing socket-related discomfort. Compared to the suboptimal outcomes of socket prostheses, osseointegration currently provides one of the best chances for any bilateral amputee to walk again and regain the ability to perform daily activities

Abstract. Objectives. Osteoporosis of the pelvis and femur is diagnosed in a high proportion of lower-limb amputees which carries an increased fracture risk and subsequently serious implications on mobility, physical dependency and morbidity. Through the development of biofidelic musculoskeletal and finite element (FE) models, we aim to determine the effect of lower-limb amputation on long-term bone remodelling in the hip and to understand the potential underpinning mechanisms for bone degradation in the younger amputee population. Methods. Our models are patient specific and anatomically accurate. Geometries are derived from MRI-scans of one bilateral, above-knee, amputee and one body-matched control subject. Musculoskeletal modelling enables comparison of muscle and joint reaction-forces throughout gait. This provides the loading scenario implemented in FE. FE modelling demonstrates the effect of loading on the amputated limb via a prosthetic socket by comparing bone mechanical stimulation in amputee and control cases. Results. Musculoskeletal modelling shows that the bilateral amputee has 25% higher peak hip-reaction force than controls but a 54% lower peak knee-reaction force. Compensation for missing muscles and joints cause large-scale changes to the muscle loading patterns of the residual limb. FE analysis shows a 32% reduction in bone stimulation within the proximal femur and an 81% reduction in the distal femoral shaft when compared to the healthy control. A shielding effect from weight-bearing through a prosthetic socket was observed that may offset any increases in joint and muscle loading at the amputated hip. Conclusions. Bone loss in the young amputee population could be driven by unloading osteopenia where altered joint and muscle loads cause altered mechanical stimulus in the femur. Over many cycles of remodelling, a net bone loss occurs. Importantly, this suggests that the issue is preventable, or even reversible, with the implementation of targeted loading regimes or changes to the design of the prosthetic socket. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction. Lower limb amputation is associated with significant morbidity and mortality. Reflecting the predominance of vascular or diabetic disease as a cause for lower limb amputation, much of the available literature excludes lower limb amputation secondary to trauma in the reporting of complication rates. This paucity in the literature represents a research gap in describing the incidence of complications in lower limb amputation due to trauma, which we aim to address. Materials and Methods. Retrospective analysis of a prospectively collected database of all traumatic lower limb amputations secondary to trauma from a regional multidisciplinary amputee service at Queen Mary's Hospital. Electronic patient records and paper notes were consulted for evidence of re-operation, infection (superficial or deep), phantom limb pain and neuroma. 222 patients were screened and 108 included in the data analysis. Results. Records identified 108 lower limb amputations secondary to trauma in 99 patients with a mean age of 34 years (at time of amputation). Average follow-up was 225 months. 33.6% of patients underwent re-operation, 25.2% had at least one episode of infection. Of those who underwent re-operation, 47.2% had evidence of infection. 42% and 3.7% of patients described phantom limb pain and neuroma respectively. Conclusions. Lower limb amputations secondary to trauma exhibit higher rates of re-operation and infection compared to vascular or diabetic amputees. This first study to provide high quality data describing the incidence of complications such as re-operation, infection, phantom limb pain and neuroma in lower limb amputations secondary to trauma

Introduction. Osseointegration has been established as a promising approach for the reconstruction of amputated limbs, particularly for amputees suffering from traditional socket prosthesis (TSP). While Osseointegration was originally developed with a screw fixation design, several Osseointegration devices adopting a modern press-fit design have also been introduced. In this study, medium-term outcomes for patients with the two most common press-fit osseointegration implant used worldwide are analysed. Materials and Methods. This is a cross-sectional analysis containing a cohort of Osseointegration patients treated in several centres worldwide. We analyzed a total of 93 patients with an average follow-up time of 6.52 years. Functional, Mobility and patient reported outcomes were collected pre-operatively and during follow-up. All postoperative adverse events (infection, revision surgery, fractures, and implant failures) were also analyzed. Results. Crude analysis of the data indicated that all 93 patients continue to use their osseointegrated prosthesis. Significant improvements for all outcome measures were observed. However, several adverse events including 19 implant revisions, 8 periprosthetic fractures and 43 surgical debridements were also reported. A detailed analysis was performed on each adverse event type to evaluate possible causes. Conclusions. At 5 years post-surgery, Osseointegration continues to provide amputees with improvements on function and quality of life which were previously unattainable with socket prosthesis. However, the benefits are accompanied with a relatively high risk of adverse events. Further research in standardizing clinical practice and the development of better implant may offer a reduction to these risks

Introduction. Osseointegration is a potential treatment option for transfemoral amputees experiencing socket related problems. Till this date, there is little data assessing the feasibility and advantages of osseointegration in individuals with transtibial amputations. Materials and Methods. We prospectively followed 91 patients undergoing transtibial osseointegration from 2014–2018 who either 1) reported pain or mobility dissatisfaction with socket prosthesis; 2) had an intact limb with incapacitating pain, complex deformity, or profound distal weakness or 3) were recent amputees preferring osseointegration. Adverse events were monitored including infection, periprosthetic fracture, implant breakage, aseptic loosening, revision surgery/additional amputation and death. Functional outcomes were measured using the Questionnaire of persons with a Trans-femoral amputation (Q-TFA) and mobility was assessed using Six Minute Walk Test (6MWT) and Time Up and Go (TUG). Results. Following osseointegration surgery, there was a significant increase in the Q-TFA global score, the 6MWT and the K-levels during follow-up. At one year following Osseointegration surgery, all patients were pain-free, the 11 patients who were wheelchair-bound prior to surgery were ambulatory, and the other 27 patient unable to walk prior to surgery, demonstrated improved mobility. There were 7 cases of implant removals due to pain and loosening and 10 cases of revisions within an average of 1.8 years, of which 1 was aseptic loosening, 6 due to infection, 1 failure to integrate and 2 implant fractures. No periprosthetic bone fractures occurred. Conclusions. Transtibial osseointegration results in improved functional outcomes after amputation. Complications are manageable and should decrease with surgical and implant improvements

Introduction. The use of osseointegrated limb replacement prostheses for amputees are rapidly growing in popularity due to the many benefits over conventional sockets. Many institutions worldwide are beginning to provide this surgical option to their patients and are advertising the service online. The aim of this study was to assess the quality and reading level of related information available online. Materials & Methods. A search was performed using the 3 most popular English language search engines reviewing the top 40 websites from each, using the term osseointegration on. Duplicates, videos, medical journal articles and dentistry websites were excluded. All included websites were assessed for reading using the FKGL, G-Fog and FRE. Quality was assessed using the JAMA benchmark criteria, HONC erificate and a novel 16-point scoring system developed specifically for limb replacement osseointegration. Results. The search resulted in 9,985,000 websites, 120 were assessed. 23 websites were included after removal of duplicates, medical journals and dentistry websites. None with reading grades of 6 or lower. Mean FKGL grade was 11.3/18. Mean FRE was 38.83/100. Mean G-FOG was 12.57/20. No websites had HONC. Mean JAMA score was 1.76/4. Mean HSSOIS was 5.70/16. Most provided information on indications(16/23) and explanation of osseointegration 17/23) but few discussed costs(3/23) or restrictions(9/23). Conclusions. There is already a large amount of information available online regarding osseointegrated prostheses. However, the most accessible information may exceed most patients’ reading levels, limiting is usefulness. Further, the information available is generally of low quality, The quality of information and the readability of online content should be improved to ensure more effective patient education

Intraneural electrodes can be harnessed to control neural prosthetic devices in human amputees. However, in chronic implants we witness a gradual loss of device functionality and electrode isolation due to a nonspecific inflammatory response to the implanted material, called foreign body reaction (FBR). FBR may eventually lead to a fibrous encapsulation of the electrode surface. Poly(ethylene glycol) (PEG) is one of the most common low-fouling materials used to coat and protect electrode surfaces. Yet, PEG can easily undergo encapsulation and oxidative damage in long-term in vivo applications. Poly(sulfobetaine methacrylate) - poly(SBMA) - zwitterionic hydrogels may represent more promising alternatives to minimize the FBR due to their ultra-low fouling features. Here, we tested and compared the poly(SBMA) zwitterionic hydrogel coating with the PEG coating in reducing adhesion and activation of pro-inflammatory and pro-fibrotic cells to polyimide surfaces, which are early hallmarks of FBR. We aimed to coat polyimide surfaces with a hydrogel thin film and analysed the release of a model drug from the hydrogel. We performed hydrogel synthesis, mechanical characterization and biocompatibility analysis. Cell adhesion, viability and morphology of human myofibroblasts cultured on PEG- and hydrogel-coated surfaces were evaluated through confocal microscopy-based high-content analysis (HCA). Reduced activation of pro-inflammatory human macrophages cultured on hydrogels was assessed as well as the hydrogel drug release profile. Because of its high hydration, biocompatibility, low stiffness and ultra-low fouling characteristics the hydrogel enabled lower adhesion and activation of pro-inflammatory and pro-fibrotic cells vs. polystyrene controls, and showed a long-term release of the anti-fibrotic drug Everolimus. Furthermore, a polyimide surface was successfully coated with a hydrogel thin film. Our soft zwitterionic hydrogel could outperform PEG as more suitable coating material of neural electrodes for mitigating the FBR. Such poly(SBMA)-based biomaterial could also be envisioned as long-term delivery system for a sustained release of anti-inflammatory and anti-fibrotic drugs in vivo

Introduction. Severe, multiplanar, fixed, pantalar deformities present a challenge to orthopaedic surgeons. Surgical options include limb salvage or amputation. This study compares outcomes of patients with such deformities undergoing limb preservation with either pantalar fusion (PTF) or talectomy and tibiocalcaneal fusion (TCF), versus below knee amputation (BKA). Methods. Fifty-one patients undergoing either PTF, TCF and BKA for failed management of severe pantalar deformity were evaluated retrospectively. Twenty-seven patients underwent PTF, 8 TCF and 16 BKA. Median age at surgery was 55.0 years (17 to 72 years) and median follow-up duration was 49.9 months (18.0 to 253.7 months). Patients with chronic regional pain syndrome, tumour, acute trauma or diabetic Charcot arthropathy were excluded. Clinical evaluation was undertaken using the MOxFQ, EQ-5D and Special Interest Group in Amputee Medicine score (SIGAM). Patients were also asked whether they were satisfied with their surgical outcome and whether they would have the same surgery again. Results. There was no statistically significant difference in patient reported outcomes, satisfaction, or complication profile between the groups. Twenty-two patients undergoing PTF (81.5%), 6 patients undergoing TCF (75%), and 15 patients undergoing BKA (93.8%) were satisfied overall (p=0.414). Similarly, there was no difference in the proportion of patients who would opt for the same procedure again (p=0.142): 23 in the PTF group (85.2%), 8 in the TCF group (100%), and 11 in the BKA group (68.8%). Seven patients undergoing PTF (25.9%), 2 patients undergoing TCF (25%) and 6 patients undergoing BKA (37.5%) had major complications (p=0.692). Conclusion. This study has shown that PTF, TCF and BKA can all provide an acceptable outcome in treatment of severe, degenerative deformities of the lower extremity. Therefore, surgical decisions must be based on individual patient considerations. This data may also be useful in counselling patients when considering limb salvage versus amputation for severe deformity

In major lower limb amputation, preservation of the knee joint significantly improves outcome. In the severely compromised limb, to preserve the knee joint, high tibial transection may be necessary creating a less than optimal stump. This study reviews the outcome in below knee amputees with stumps 10cm or shorter. All 209 below knee (BK) amputees attending the New Zealand Artificial Limb Board’s Dunedin Centre were reviewed. The centre is the sole provider of prosthetic services in the southern region. Forty-four amputees (21% of total) had stumps of 10cm or less in length as measured by caliper rule. After a minimum twelve month follow-up these amputees were placed in two groups. Group 1: Short Stump (10cm to 8cm). Group 2: Ultra Short Stump (7.5cm to 5cm). Wood-Stanmore Grades were given for walking ability (Hanspal and Fisher 1991). Rehabilitation was further assessed using a modified Houghton Questionnaire (Houghton et al 1992). Mean stump length for all 209 BK amputees was 12.5 centimeters (range 5 to 25 centimeters). Group 1. Short Stump (ten to eight centimeters 0 – 37 amputees. Nineteen amputees – Good to Excellent (Wood – Stanmore Grade V and V1) i.e. walking indoors and outdoors without aids and with near normal gait. (10 trauma, four dysvascular, four tumour, one infection). Fourteen amputees-Satisfactory (Grade 1V) i.e. walking aid indoors and outdoors (13 dysvascular, one congenital). 4 amputees – Fair Only (Grade 111) i.e. mostly indoors with frame (four dysvascular). Group 2. Ultra Short Stump (7.5cm to 5cm) – seven amputees. Six amputees – Good to Excellent (Grade V or V1) – (all trauma). One amputee – Fair Only (Grade 111) – (dysvascular). Group one mostly had a posterior myocutaneous flap amputation with retention of the proximal fibula. In Group two, all had resection of the proximal fibula with varied flaps often with skin grafting. The patellar tendon was intact but two patients had lost the hamstring insertion with hyperextension of the knee, one requiring prosthesis with side steels and thigh corset. In group two the best results followed high resection of the common peroneal nerve and careful shaping of the tibial remnant. Cortical bone formed at the transection level allowing total contact prosthetic fitting with some end bearing. BK amputation is described as optimally 12.5 centimeters to 17.5 centimeters below the knee joint (10 to 12.5 centimeters in vascular disease). Saving the knee should always be considered and with combined surgical and prosthetic skill a stump as short as five centimeters may be fitted satisfactorily particularly in the young and following trauma

A major cause of morbidity in lower limb amputees is phantom limb pain (PLP) and residual limb pain (RLP). This study aimed to determine if surgical interposition of nerve endings into adjacent muscle bellies at the time of major lower limb amputation can decrease the incidence and severity of PLP and RLP. Data was retrospectively collected from January 2015 to January 2021, including eight patients that underwent nerve interposition (NI) and 36 that received standard treatment. Primary outcomes included the 11-point Numerical Rating Scale (NRS) for pain severity, and Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity, behaviour, and interference. Secondary outcome included Neuro-QoL Lower Extremity Function assessing mobility. Cumulative scores were transformed to standardised t scores. Across all primary and secondary outcomes, NI patients had lower PLP and RLP. Mean ‘worst pain’ score was 3.5 out of 10 for PLP in the NI cohort, compared to 4.89 in the control cohort (p=0.298), and 2.6 out of 10 for RLP in the NI cohort, compared to 4.44 in the control cohort (p=0.035). Mean ‘best pain’ and ‘current pain’ scores were also superior in the NI cohort for PLP (p=0.003, p=0.022), and RLP (p=0.018, p=0.134). Mean PROMIS t scores were lower for the NI cohort for RLP (40.1 vs 49.4 for pain intensity; p=0.014, 44.4 vs 48.2 for pain interference; p=0.085, 42.5 vs 49.9 for pain behaviour; p=0.025). Mean PROMIS t scores were also lower for the NI cohort for PLP (42.5 vs 52.7 for pain intensity; p=0.018); 45.0 vs 51.5 for pain interference; p=0.015, 46.3 vs 51.1 for pain behaviour; p=0.569). Mean Neuro-QoL t score was lower in NI cohort (45.4 vs 41.9;p=0.03). Surgical interposition of nerve endings during lower limb amputation is a simple yet effective way of minimising PLP and RLP, improving patients’ subsequent quality of life. Additional comparisons with targeted muscle reinnervation should be performed to determine the optimal treatment option

Advances in military surgery have led to significant numbers of soldiers surviving with bilateral above knee amputations. Despite advances in prosthetic design and high quality rehabilitation not all amputees succesfully ambulate. Five patients (10 stumps) with persisting socket fit issues were selected for osseointegration (OI) using a transcutaneous prosthesis with press-fit fixation in the residual femur. Prior to surgery all five were primarily/exclusively wheelchair users. Follow up was from 7 to 25 months (mean 12.2). There were no deaths, episodes of sepsis or osteomyelitis. There was one proximal femoral fracture secondary to a fall. One stump required soft tissue refashioning. Cellulitis needing oral antibiotics occurred in four cases. Functional improvement occurred in all cases with all currently primarily prosthetic users, the majority all day users. Three patients are still completing rehabilitation. Six minute walk tests (SMWT) improved by a mean of 20%. Three are now graded mobility SIGAM F (normal gait) and two SIGAM D-b (limited terrain; with one stick). This cohort suggests that OI may have a role in the treatment of military blast amputees. A larger scale clinical evaluation is planned in the UK blast related amputee population to further establish the benefits and risks of this technique

The anatomy of the femur shows a high inter-patient variability, making it challenging to design standard prosthetic devices that perfectly adapt to the geometry of each individual. Over the past decade, Statistical Shape Models (SSMs) have been largely used as a tool to represent an average shape of many three-dimensional objects, as well as their variation in shape. However, no studies of the morphology of the residual femoral canal in patients who have undergone an amputation have been performed. The aim of this study was therefore to evaluate the main modes of variation in the shape of the canal, therefore simulating and analysing different levels of osteotomy. To assess the variability of the femoral canal, 72 CT-scans of the lower limb were selected. A segmentation was performed to isolate the region of interest (ROI), ranging from the lesser tip of the trochanter to the 75% of the length of the femur. The canals were then sized to scale, aligned, and 16 osteotomy levels were simulated, starting from a section corresponding to 25% of the ROI and up to the distal section. For each level, the main modes of variations of the femoral canal were identified through Principal Component Analysis (PCA), thus generating the mean geometry and the extreme shapes (±2 stdev) of the principal modes of variation. The shape of the canals obtained from these geometries was reconstructed every 10 mm, best- fitted with an ellipse and the following parameters were evaluated: i) ellipticity, by looking at the difference between axismax and axismin; ii) curvature of the canal, calculating the arc of circumference passing through the shapes’ centroids; iii) conicity, by looking at the maximum/minimum diameter; iv) mean diameter. To understand the association between the main modes and the shape variance, these parameters were compared, for each level of osteotomy, between the two extreme geometries of the main modes of variation. Results from PCA pointed out that the first three PCs explained more than the 87% of the total variance, for each level of simulated osteotomy. By analysing the extreme geometries for a distal osteotomy (e.g. 80% of the length of the canal), the first PC was associated to a combination of ROC (var%=41%), conicity (var%=28%) and ellipticity (var%=7%). PC2 was still associated with the ROC (var%=16%), while PC3 turned out to be associated with the diameter (var%=38%). Through the SSM presented in this study, a quantitatively evaluation of the deformation of the intramedullary canal has been made possible. By analysing the extreme geometries obtained from the first three modes of variance, it is clear that the first three PCs accounted for the variations in terms of curvature, conicity, ellipticity and diameter of the femoral canal with a different weight, depending on the level of osteotomy. Through this work, it was also possible to parametrize these variations according to the level of excision. The results given for the segment corresponding to the 80% of the length of the canal showed that, at that specified level, the ROC, conicity and ellipticity were the anatomical parameters with the highest range of variability, followed by the variation in terms of diameter. Therefore, the analysis carried out can provide information about the relevance of these parameters depending on the level of osteotomy suffered by the amputee. In this way, optimal strategies for the design and/or customization of osteo-integrated stems can be offered depending on the patient's residual limb