The Vega advanced third generation posterior stabilized total knee arthroplasty system enables the restoration of range of motion for high demanding daily activities - A 5-years follow-up study.

BACKGROUND: The Vega System® PS (Aesculap AG, Tuttlingen, Germany) is an advanced, third generation fixed implant that aims to mimic natural knee kinematics by optimizing pivotal motion while reducing surface stress. This study evaluated mid-term survival and clinical outcomes, including range of motion (ROM) of the modern posterior stabilized implant in order to analyse whether this biomechanically successful implant reaches good results in situ. METHODS: The first 100 patients to receive the Vega PS System for total knee arthroplasty were invited to take part in this single centre, single surgeon study. Of these, 84 patients were clinically assessed 5-6 years postoperatively. Data which was obtained during this follow-up examination included revision data, range of motion and clinical scores. RESULTS: The 5-year survival rate for exchange of any component was 97.6%, whereby two patients required replacement of the polyethylene gliding surface. Secondary patella resurfacing was performed in 7 patients. Significantly improved results in comparison to the preoperative state could be obtained at the follow-up: KOOS improved from 39.4 to 78.8, SF-12 PCS improved from 32.1 to 42 SF-12 MCS improved from 46 to 53.8 and patella pain improved from 2.7 to 0.3. The mean ROM of the 84 patients after 5 years was 133.1° and mean total KSS was 189.9. DISCUSSION & CONCLUSIONS: This study demonstrates a high survival rate of the Vega PS System® and significant improvements in clinical outcomes 5 years after implantation. The obtained mean ROM indicates that this implant provides good flexibility of the knee joint, allowing a high number of activities. However, due to the rate of secondary patella implantation, routine resurfacing of the patella for all PS TKA cases is highly recommended. CLINICAL TRIALS REGISTRATION: The study was registered at clinicaltrials.gov (NCT02802085).

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.

Techniques to Remove Press-Fit Osseointegration Implants.

Background: Transcutaneous osseointegration for amputees (TOFA) has proven to consistently, significantly improve the quality of life and mobility for the vast majority of amputees, as compared with the use of a socket prosthesis1,2. As with any implant, situations such as infection, aseptic loosening, or implant fracture can occur, which may necessitate hardware removal. Although it may eventually occur, to date no osseointegration implant has ever required removal in the setting of periprosthetic fracture. Since TOFA implants are designed to facilitate robust bone integration, removal can be challenging. Even in cases in which portions of the implant are loose, other areas of the implant may remain strongly integrated and resist removal. Further, there can be cases in which an implant fractures, leaving the residual portion of the implant in place without the interface for an extraction tool. Although the outcomes of revision osseointegration has not been the primary focus of any publication, the fact that revision can be necessary and generally succeeds in restoring similar mobility has been documented3-5. As with any hardware removal, preserving healthy tissue and avoiding iatrogenic injury are critically important. This article demonstrates several techniques to remove press-fit osseointegration implants that we have found safe and effective. Description: The procedure is performed with the patient in the supine position and with the affected extremity prepared and draped in a typical sterile fashion. The use of a tourniquet can help reduce blood loss, but it may be safer to not use a tourniquet during the portions of the procedure that create increased or prolonged bone thermal exposure, such as during reaming or drilling. If patients are clinically stable, withholding antibiotics until cultures are obtained may improve diagnostic yield. The implant removal technique should proceed from conservative to aggressive, as necessary: slap hammer, thin wire-assisted slap hammer, and extended osteotomy. Trephine reaming is discouraged because of the need for and difficulty of removing the dual cone interface portion of the implant, along with the extensive damage often caused to the surrounding bone during reaming, which can be avoided with the osteotomy technique. Alternatives: It is important to emphasize that most infections related to transcutaneous osseointegration do not require implant removal; the use of antibiotics alone or soft-tissue and/or limited bone debridement is sufficient to resolve infection in the majority of cases. If a patient has a non-infectious indication for removal (such as a loose implant) but declines surgery, activity modification with close observation may be reasonable. If a patient has an infectious indication for removal but declines surgery, very close observation must be maintained to avoid potential osteomyelitis. The use of suppressive antibiotics (oral and/or intravenous) may help reduce the severity of the infection. An alternative surgery to manage implant-associated infection can be amputation above the implant (within the same bone, through-joint amputation, or through the femur for a transtibial osseointegration). This should be considered only if there is a tremendously compelling reason to do so, such as an emergency need to amputate due to a life-threatening infection. Rationale: Indications for implant removal include persistent pain, deep infection recalcitrant to soft-tissue or bone debridement and implant retention, or mechanical complications involving the implant, such as loosening or breakage. The following are specific examples of indications for removal: infection that cannot be resolved with oral and/or intravenous antibiotics or with debridement of soft tissue and/or bone, implants that have not achieved or not maintained stable integration (aseptic or loosening) and are causing pain, and implants that have fractured or have deformed and are a concern for fracture. Expected Outcomes: Most patients who require removal of press-fit osseointegration implants are suitable for reimplantation after a decontamination period involving a local antibiotic depot and intravenous antibiotics. This duration is often 6 to 12 weeks. Following revision osseointegration, patients generally achieve similar levels of performance as they had during the stable period prior to removal3-5. Infection does not appear to be associated with an increased risk of mortality6. Patients who decline revision osseointegration are able to return to the use of a socket prosthesis. Important Tips: Infection is often treatable with use of oral and/or intravenous antibiotics, with or without soft-tissue and/or bone debridement. Consider these options before reflexively removing an implant.Preserving bone stock and quality is important for an optimal revision to another osseointegration prosthesis or conversion to a socket prosthesis. Living bone, even if infected, can be decontaminated with antibiotics. Minimize thermal injury by releasing the tourniquet and using saline solution irrigation during reaming or similar portions of the procedure. If the implant can only be removed by fully removing a portion of bone (rather than through a single clamshell-type osteotomy), attempt screw osteosynthesis to preserve a canal for future osseointegration.Be gentle and patient during the removal techniques. Elevating bone quickly or violently may cause propagating fractures, increased morbidity, or splinter bone fragments. Carefully separating bone from implant will reduce bone loss and preserve the bone condition for a potential revision.Although patients may not appear to have an infection in some cases, it is advised to treat every removal as if it involves an infection. The first surgical stage should be for removal, culture acquisition, and decontamination with antibiotics. A separate second surgery can be performed after the antibiotics have eradicated infection.Many implants have been removed with slap hammer or fine wire techniques; osteotomy should be reserved for situations in which diligent attempts using these techniques have proven unsuccessful, in order to optimize bone integrity.

Transfemoral amputation versus knee arthrodesis for failed total knee replacement: A systematic review of outcomes.

BACKGROUND: The options available to salvage a failed total knee replacement (TKR) include transfemoral amputation (TFA) and knee arthrodesis (KA). This systematic review aims to evaluate outcomes following either TFA or KA, comparing ambulatory status, additional subsequent surgery, postoperative infection, pain, health-related quality of life (HRQoL), and mortality rate. METHODS: A literature search was conducted in EMBASE, Ovid Medline, and PubMed. Only primary research studies were included and data were independently extracted using a standardized form. The methodological quality of the studies was evaluated using Newcastle-Ottawa Scale. RESULTS: Forty-four papers were included, comprising 470 TFA and 1034 KA patients. The methodological quality of the studies was moderate. No TFA versus KA randomized controlled trials could be identified. Pooled data totals via subgroup analyses were performed, owing to inconsistent reporting methods in the included studies. Prosthesis use rate by TFA patients was 157/316 = 49.7%. Significant differences included that TFA patients had lower rates of ambulatory capacity than KA patients (139/294 = 45.6% versus 248/287 = 86.4%, p < 0.001), TFA ambulators were less likely to use an ambulatory aid (55/135 = 40.7% versus 167/232 = 72.0%, p < 0.001), and TFA was associated with a greater postoperative infection rate than KA (29/118 = 24.6% versus 129/650 = 17.2%, p = 0.054). There was a similar rate of revision surgery between TFA and KA (37/183 = 20.2% versus 145/780 = 18.6%, p = 0.612). Data on HRQoL for both TFA and KA were limited, contradictory, and heterogeneous. CONCLUSION: No randomized controlled trials comparing TFA versus KA exist;therefore, current data likely reflects substantial selection bias. The currently available evidence suggests that KA patients are significantly more likely to achieve independent bipedal ambulation than TFA patients. In both treatment cohorts, subsequent infection and revision surgery remain a relatively common occurrence.

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

Aims: Safety concerns surrounding osseointegration are a significant barrier to replacing socket prosthesis as the standard of care following limb amputation. While implanted osseointegrated prostheses traditionally occur in two stages, a one-stage approach has emerged. Currently, there is no existing comparison of the outcomes of these different approaches. To address safety concerns, this study sought to determine whether a one-stage osseointegration procedure is associated with fewer adverse events than the two-staged approach. Methods: A comprehensive electronic search and quantitative data analysis from eligible studies were performed. Inclusion criteria were adults with a limb amputation managed with a one- or two-stage osseointegration procedure with follow-up reporting of complications. Results: A total of 19 studies were included: four one-stage, 14 two-stage, and one article with both one- and two-stage groups. Superficial infection was the most common complication (one-stage: 38% vs two-stage: 52%). There was a notable difference in the incidence of osteomyelitis (one-stage: nil vs two-stage: 10%) and implant failure (one-stage: 1% vs two-stage: 9%). Fracture incidence was equivocal (one-stage: 13% vs two-stage: 12%), and comparison of soft-tissue, stoma, and mechanical related complications was not possible. Conclusion: This review suggests that the one-stage approach is favourable compared to the two-stage, because the incidence of complications was slightly lower in the one-stage cohort, with a pertinent difference in the incidence of osteomyelitis and implant failure.

Bone density changes after five or more years of unilateral lower extremity osseointegration: Observational cohort study.

Context: Rehabilitation following lower extremity amputation presents multiple challenges, many related to the traditional prosthesis (TP) socket. Without skeletal loading, bone density also rapidly decreases. Transcutaneous osseointegration for amputees (TOFA) surgically implants a metal prosthesis attachment directly into the residual bone, facilitating direct skeletal loading. Quality of life and mobility are consistently reported to be significantly superior with TOFA than TP. Objective: To investigate how femoral neck bone mineral density (BMD, g/cm2) changes for unilateral transfemoral and transtibial amputees at least five years following single-stage press-fit osseointegration. Methods: Registry review was performed of five transfemoral and four transtibial unilateral amputees who had dual x-ray absorptiometry (DXA) performed preoperatively and after at least five years. The average BMD was compared using Student's t-test (significance p < .05). First, all nine Amputated versus Intact limbs. Second, the five patients with local disuse osteoporosis (ipsilateral femoral neck T-score < -2.5) versus the four whose T-score was greater than -2.5. Results: The average Amputated Limb BMD was significantly less than the Intact Limb, both Before Osseointegration (0.658 ± 0.150 vs 0.929 ± 0.089, p < .001) and After Osseointegration (0.720 ± 0.096 vs 0.853 ± 0.116, p = .018). The Intact Limb BMD decreased significantly during the study period (0.929 ± 0.089 to 0.853 ± 0.116, p = .020), while the Amputated Limb BMD increased a not statistically significant amount (0.658 ± 0.150 to 0.720 ± 0.096, p = .347). By coincidence, all transfemoral amputees had local disuse osteoporosis (BMD 0.545 ± 0.066), and all transtibial patients did not (BMD 0.800 ± 0.081, p = .003). The local disuse osteoporosis cohort eventually had a greater average BMD (not statistically significant) than the cohort without local disuse osteoporosis (0.739 ± 0.100 vs 0.697 ± 0.101, p = .556). Conclusions: Single-stage press-fit TOFA may facilitate significant BMD improvement to unilateral lower extremity amputees with local disuse osteoporosis.

Transcutaneous osseointegration for amputees with burn trauma.

OBJECTIVE: Transcutaneous osseointegration for amputees (TOFA) surgically implants a prosthetic anchor into the residual limb's bone, enabling direct skeletal connection to a prosthetic limb and eliminating the socket. TOFA has demonstrated significant mobility and quality of life benefits for most amputees, but concerns regarding its safety for patients with burned skin have limited its use. This is the first report of the use of TOFA for burned amputees. METHODS: Retrospective chart review was performed of five patients (eight limbs) with a history of burn trauma and subsequent osseointegration. The primary outcome was adverse events such as infection and additional surgery. Secondary outcomes included mobility and quality of life changes. RESULTS: The five patients (eight limbs) had an average follow-up time of 3.8 ± 1.7 (range 2.1-6.6) years. We found no issues of skin compatibility or pain associated with the TOFA implant. Three patients underwent subsequent surgical debridement, one of whom had both implants removed and eventually reimplanted. K-level mobility improved (K2 +, 0/5 vs 4/5). Other mobility and quality of life outcomes comparisons are limited by available data. CONCLUSION: TOFA is safe and compatible for amputees with a history of burn trauma. Rehabilitation capacity is influenced more by the patient's overall medical and physical capacity than their specific burn injury. Judicious use of TOFA for appropriately selected burn amputees seems safe and merited.

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

BACKGROUND: The literature comparing bone-anchored prosthesis (BAP) with socket prosthesis (SP) consistently reports improvement in physical health and quality of life using primarily patient-reported outcome measures (PROMs). OBJECTIVE: To determine the differences in mobility and balance using performance-based outcome measures and PROMs in people with transfemoral amputations (TFAs) fitted with BAP vs. SP. STUDY DESIGN: Causal comparative. METHODS: Two groups of people with TFAs were recruited: one using a BAP (N = 11; mean age ± standard deviation, 44 ± 14.9 years; mean residual limb length as a percentage of the intact femur, 68% ± 15.9) and another group using a SP (N = 11; mean age ± standard deviation, 49.6 ± 16.0 years; mean residual limb length as a percentage of the intact femur, 81% ± 13.9), and completed the 10-meter walk test, component timed-up-and-go, Prosthetic Limb Users Survey of Mobility™ 12-item, and Activities-specific Balance Confidence Scale. RESULTS: There were no statistically significant differences between the BAP and SP groups in temporal spatial gait parameters and prosthetic mobility as measured by the 10-meter walk test and component timed-up-and-go, yet large effect sizes were found for several variables. In addition, Activities-specific Balance Confidence Scale and Prosthetic Limb Users Survey of Mobility™ scores were not statistically different between the BAP and SP groups, yet a large effect sizes were found for both variables. CONCLUSIONS: This study found that people with TFA who use a BAP can demonstrate similar temporal spatial gait parameters and prosthetic mobility, as well as self-perceived balance confidence and prosthetic mobility as SP users. Therefore, suggesting that the osseointegration reconstruction surgical procedure provides an alternative option for a specific population with TFA who cannot wear nor have limitations with a SP. Future research with a larger sample and other performance-based outcome measures and PROMs of prosthetic mobility and balance would further determine the differences between the prosthetic options.

Association Between Osseointegration of Lower Extremity Amputation and Mortality Among Adults.

Importance: Transcutaneous osseointegration post amputation (TOPA) creates a direct linkage between residual bone and an external prosthetic limb, providing superior mobility and quality of life compared with a socket prosthesis. The causes and potential risks of mortality after TOPA have not been investigated. Objective: To investigate the association between TOPA and mortality and assess the potential risk factors. Design, Setting, and Participants: This observational cohort study included all patients with amputation of a lower extremity who underwent TOPA between November 1, 2010, and October 31, 2021, at a specialty orthopedic practice and tertiary referral hospital in a major urban center. Patients lived on several continents and were followed up as long as 10 years. Exposures: Transcutaneous osseointegration post amputation, consisting of a permanent intramedullary implant passed transcutaneously through a stoma and connected to an external prosthetic limb. Main Outcomes and Measures: Death due to any cause. The hypotheses tested-that patient variables (sex, age, level of amputation, postosseointegration infection, and amputation etiology) may be associated with subsequent mortality-were formulated after initial data collection identifying which patients had died. Results: A total of 485 patients were included in the analysis (345 men [71.1%] and 140 women [28.9%]), with a mean (SD) age at osseointegration of 49.1 (14.6) years among living patients or 61.2 (12.4) years among patients who had died. Nineteen patients (3.9%) died a mean (SD) of 2.2 (1.7) years (range, 58 days to 5 years) after osseointegration, including 17 (3.5%) who died of causes unrelated to osseointegration (most commonly cardiac issues) and 2 (0.4%) who died of direct osseointegration-related complications (infectious complications), of which 1 (0.2%) was coclassified as a preexisting health problem exacerbated by osseointegration (myocardial infarction after subsequent surgery to manage infection). No deaths occurred intraoperatively or during inpatient recuperation or acute recovery after index osseointegration (eg, cardiopulmonary events). Kaplan-Meier survival analysis with log-rank comparison and Cox proportional hazards regression modeling identified increased age (hazard ratio, 1.06 [95% CI, 1.02-1.09]) and vascular (odds ratio [OR], 4.73 [95% CI, 1.35-16.56]) or infectious (OR, 3.87 [95% CI, 1.31-11.40]) amputation etiology as risk factors. Notable factors not associated with mortality risk included postosseointegration infection and male sex. Conclusions and Relevance: These findings suggest that patients who have undergone TOPA rarely die of problems associated with the procedure but instead usually die of unrelated causes.

Osseointegration Following Transfemoral Amputation After Infected Total Knee Replacement: A Case Series of 10 Patients With a Mean Follow-up of 5 Years.

Background: Management of total knee replacement (TKR) infection may sometimes prompt knee fusion (KF) or transfemoral amputation (TFA), both associated with low mobility and quality of life (QOL). Transcutaneous osseointegration for amputees provides superior mobility and QOL vs traditional socket prostheses but has not been studied for patients with a history of infected TKR. This study investigates the following hypothesis: Patients who have had TFA or KF following infected TKR achieve better mobility and QOL following transfemoral osseointegration. Material and methods: A retrospective evaluation of the prospectively maintained registry identified 10 patients who had prior infected TKR. The mobility assessments (patient daily prosthesis wear time, K-level, Timed Up and Go, 6-Minute Walk Test) and QOL surveys (Questionnaire for Persons with a Transfemoral Amputation Global, Mobility, and Problem scores) were compared preoperatively and after at least 2 years. Complications requiring an additional surgery were also evaluated. Results: Daily wear hours, K-level, and 6-Minute Walk Test and Questionnaire for Persons with a Transfemoral Amputation Global and Problem scores significantly improved (P < .05). Through 1 year, 4 patients (40%) had additional surgeries. After several years, 7 patients (70%) had at least 1 additional surgery, and 5 (50%) had multiple, for an average of 1 debridement and 1.3 soft-tissue refashionings per patient. One patient died of newly diagnosed cancer 1 year after transcutaneous osseointegration for amputees. Conclusion: Transfemoral osseointegration confers significantly better mobility and QOL vs KF or a TFA with traditional socket prostheses following infected TKR. Technique improvements to prevent subsequent surgeries may provide an increasingly streamlined experience.

The Clinical History and Basic Science Origins of Transcutaneous Osseointegration for Amputees.

Transcutaneous osseointegration for amputees (TOFA) refers to an intramedullary metal endoprosthesis which passes transcutaneously to connect with a limb exoprosthesis. The first recognizably modern experiments and attempts occurred in the 1940s. Multiple researchers using a plethora of materials and techniques over the following 50 years identified principles and obstacles which informed the first long-term successful surgery in 1990. Unfortunately, the current mainstream TOFA literature presents almost exclusively subsequent developments, generally omitting prior research, leading to some historical mistakes being repeated. Given the increasing interest and surgical volume of TOFA, this literature review was performed to delineate TOFA's basic science and surgical origins and to integrate these early efforts within the contemporary understanding. Studying this research could protect and benefit future patients, surgeons, and implant developers as TOFA is entering a phase of increased attention and innovation. The aim of this article is to provide a focused reference of foundational research, much of which is difficult to identify and retrieve, for clinicians and researchers.

Transtibial Osseointegration for Patients with Peripheral Vascular Disease: A Case Series of 6 Patients with Minimum 3-Year Follow-up.

The management of peripheral vascular disease (PVD) can require amputation. Osseointegration surgery is an emerging rehabilitation strategy for amputees. In this study, we report on 6 patients who had PVD requiring transtibial amputation (PVD-TTA) and either simultaneous or subsequent osseointegration (PVD-TTOI). METHODS: Six patients (aged 36 to 84 years) with transtibial amputation and preexisting PVD underwent osseointegration between 2014 and 2016 and were followed for 3 to 5 years. Pre- and postoperative clinical and functional outcomes (pain, prosthesis wear time, mobility, walking ability, and quality of life) and adverse events (infection, fracture, implant failure, revision surgery, additional amputation, and death) were prospectively recorded. RESULTS: All patients' mobility improved following osseointegration. Three patients initially had required the use of a wheelchair, precluding baseline walking tests; the other 3 were classified as K level 1 or 2, with mean baseline Timed Up and Go (TUG) test = 14.0 ± 2.2 s and 6-Minute Walk Test (6MWT) = 262 ± 75 m. At the time of the latest follow-up, all patients were K level 2 or 3; mean TUG = 12.7 ± 7.2 s and 6MWT = 353 ± 148 m. Four patients wore their prosthesis ≥16 hours daily. Three patients had superficial soft-tissue infections. One other patient experienced recurrent infections 2.8 years after osseointegration requiring debridements and transfemoral amputation; the patient died 2 days following surgery from myocardial infarction caused by coronary atherosclerosis. CONCLUSIONS: All 6 patients who underwent PVD-TTOI in this case series survived through 2 years. Patients who initially had used a wheelchair achieved and maintained independent, unaided ambulation until PVD-related impairments in the contralateral leg occurred in 1 patient. Patients previously using a traditional socket prosthesis reported improvement in mobility and quality of life. One patient's death underscores the importance of careful patient selection. However, marked improvement in the other 5 patients suggests cautious optimism that PVD-TTA is not an absolute osseointegration contraindication. Conscientious further investigation seems appropriate. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Pelvic Osseointegration for Unilateral Hip Disarticulation: A Case Report.

CASE: A 24-year-old man with right unilateral hip disarticulation, intolerant of a traditional socket-mounted prosthesis (TSP), underwent pelvic transcutaneous osseointegration and was fit with a prosthetic lower extremity 7 months later. Twenty-four months after osseointegration, he remains pain-free and complication-free, wears his prosthesis all waking hours, walks without assistive devices and can carry 2-handed objects, and works as a livestock farmer. CONCLUSION: Through 24 months, the world's first patient with pelvic osseointegration has no complications and better mobility than most patients with unilateral hip disarticulation using TSPs. Pelvic osseointegration seems reasonable to further consider in carefully selected patients.

Amputation With Osseointegration for Patients With Intractable Complex Regional Pain Syndrome: A Report of 3 Cases.

CASES: Three patients with knee-level complex regional pain syndrome type 1 (CRPS1), recalcitrant to conservative interventions, elected for transfemoral amputation and osseointegration. Two patients gained independent ambulation; the third remains on crutches after a disrupted sciatic nerve targeted reinnervation. One uses no pain medication, one is weaning off, and one requires a reduced regimen after revision nerve innervation. CONCLUSION: Osseointegration seems suitable to optimize rehabilitation after amputation for CRPS1.

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.

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.

Cementing Osseointegration Implants Results in Loosening: Case Report and Review of Literature.

Skeletal transcutaneous osseointegration was performed on a 54-year-old female transfemoral amputee. None of the available osseointegration implants achieved press-fit stability, so an implant was cemented in position. Although initially stable, by six months the patient reported painful loading and radiographs revealed cement mantle lucency. The osseointegration implant was removed, antibiotics were delivered via implanted spacer and intravenously, and revision osseointegration three months later achieved appropriate immediate press-fit stability. Cemented transcutaneous osseointegration implants loosen within one year. Osseointegration is only successful when bone grows directly onto the implant.

Periprosthetic osseointegration fractures are infrequent and management is familiar.

AIMS: Osseointegrated prosthetic limbs allow better mobility than socket-mounted prosthetics for lower limb amputees. Fractures, however, can occur in the residual limb, but they have rarely been reported. Approximately 2% to 3% of amputees with socket-mounted prostheses may fracture within five years. This is the first study which directly addresses the risks and management of periprosthetic osseointegration fractures in amputees. METHODS: A retrospective review identified 518 osseointegration procedures which were undertaken in 458 patients between 2010 and 2018 for whom complete medical records were available. Potential risk factors including time since amputation, age at osseointegration, bone density, weight, uni/bilateral implantation and sex were evaluated with multiple logistic regression. The mechanism of injury, technique and implant that was used for fixation of the fracture, pre-osseointegration and post fracture mobility (assessed using the K-level) and the time that the prosthesis was worn for in hours/day were also assessed. RESULTS: There were 22 periprosthetic fractures; they occurred exclusively in the femur: two in the femoral neck, 14 intertrochanteric and six subtrochanteric, representing 4.2% of 518 osseointegration operations and 6.3% of 347 femoral implants. The vast majority (19/22, 86.4%) occurred within 2 cm of the proximal tip of the implant and after a fall. No fractures occurred spontaneously. Fixation most commonly involved dynamic hip screws (10) and reconstruction plates (9). No osseointegration implants required removal, the K-level was not reduced after fixation of the fracture in any patient, and all retained a K-level of ≥ 2. All fractures united, 21 out of 22 patients (95.5%) wear their osseointegration-mounted prosthetic limb longer daily than when using a socket, with 18 out of 22 (81.8%) reporting using it for ≥ 16 hours daily. Regression analysis identified a 3.89-fold increased risk of fracture for females (p = 0.007) and a 1.02-fold increased risk of fracture per kg above a mean of 80.4 kg (p = 0.046). No increased risk was identified for bilateral implants (p = 0.083), time from amputation to osseointegration (p = 0.974), age at osseointegration (p = 0.331), or bone density (g/cm2, p = 0.560; T-score, p = 0.247; Z-score, p = 0.312). CONCLUSION: The risks and sequelae of periprosthetic fracture after press-fit osseointegration for amputation should not deter patients or clinicians from considering this procedure. Females and heavier patients are likely to have an increased risk of fracture. Age, years since amputation, and bone density do not appear influential. Cite this article: Bone Joint J 2020;102-B(2):162-169.

Proximal Bone Remodeling in Lower Limb Amputees Reconstructed With an Osseointegrated Prosthesis.

Mobility outcomes and changes in bone mineral density (BMD) of the spine and femoral necks in response to unilateral osseointegrated implants was investigated over a 3-year period. A total of 48 unilateral amputees who received an osseointegrated implant, comprising 33 trans-femoral amputees (TFA) and 15 trans-tibial amputees (TTA), underwent dual-energy X-ray absorptiometry (DXA) scans of the lumbar spine (L2-L4) and femoral necks at baseline, 1-, and 3-years follow-ups. Mobility outcomes, including the Six-Minute-Walk Test (6MWT) and Timed-Up-and-Go (TUG), were measured before surgery, at 1 year, and more than 2 years following the osseointegration procedure. We observed a significant increase (p < 0.05) in Z-score values in the femoral neck of the amputated side in TFA patients without a femoral neck lag screw at the 1- and 3-year follow-ups, as well as in TFA patients with a lag screw present at 3-year follow-up. The BMD at 1-year follow-up was found to be positively correlated with pre-surgery 6MWT values in patients who were mobile using a traditional socket prosthesis before receiving an osseointegrated implant. These results suggest that osseointegrated implants induce a physiological response in the femoral neck of recipients and appear to be evidence of restored biomechanical loading in the proximal femur. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2524-2530, 2019.