Transfemoral Osseointegration in Association With Total Hip Replacement: Observational Cohort Study of Patients With Follow-Up Exceeding 2 Years.

Background: Some amputees with transfemoral osseointegration (TFOI) have ipsilateral hip arthritis which can be addressed with total hip arthroplasty (THA). This study reported the medium-term outcomes of THA in association with TFOI (THA + TFOI). Methods: Retrospective review was performed for eight patients with THA + TFOI performed at least 2 years prior. Primary outcomes include complications prompting surgical intervention. Secondary outcomes include changes in mobility (K-level, 6-minute walk test [6MWT], timed up and go) and patient-reported measures (hip pain, daily prosthesis wear hours, Questionnaire for Persons with a Transfemoral Amputation, and Short Form 36 [SF36]). Results: One patient died after 11 months (cancer); he was included to maximally report complications but excluded from mobility and reported outcomes. Three patients required subsequent surgeries: Two had skin refashioning, and the other underwent hip debridement of the replaced joint with subsequent removal of the TFOI. No perioperative complications, fractures, or arthroplasty explantations occurred. All patients reported complete hip pain relief. Of 6 patients reporting prosthesis wear time, 2 (33%) wore their prosthetic leg at least 4 hours daily before, vs all (100%) who did afterward (P = .061). K-levels improved in all responding patients. All 5 wheelchair-bound patients achieved and maintained ambulation. The Questionnaire for Persons with a Transfemoral Amputation and Short Form 36 did not significantly change. Conclusions: THA + TFOI does not appear to pose an inevitable risk for prosthetic hip infection and may improve mobility and enhance quality of life (QOL) for transfemoral amputees with concurrent arthritic hip pain who are dissatisfied with their outcome following traditional socket prosthesis rehabilitation.

Single-Stage Press-Fit Osseointegration of the Radius and Ulna for Rehabilitation After Trans-Forearm Amputation.

Background: Upper limb (UL) amputation is disabling. ULs are necessary for many domains of life1, and few effective motor and sensory replacements are accessible2. Approximately 41,000 people in the United States have UL amputation proximal to the fingers3, two-thirds of (all) traumatic amputations are UL4, and 80% of UL amputations are performed for trauma-related etiologies5. Socket prosthesis (SP) abandonment remains high because of the lack of sensation, limited prosthesis control, perceived weight, and difficulty comfortably wearing the SP6. Transcutaneous osseointegration7,8 surgically inserts a bone-anchored implant, passed through a transcutaneous portal to attach a terminal device, improving amputee rehabilitation by reducing perceived weight, conferring osseoperception9, and increasing wear time10. Without the socket, all residual skin and musculature remain available for transcutaneous myoelectrodes. The present article describes single-stage radius and ulna press-fit osseointegration (PFOI) after trans-forearm amputation. Description: This technique resembles a lower-extremity PFOI11,12. Importantly, at-risk nerves and vessels are different, and implant impaction must be gentler as a result. The surgery is indicated for patients who are dissatisfied with SP rehabilitation or declining alternative rehabilitative options, and who are motivated and enabled to procure, train with, and utilize a forearm prosthesis. An engaged prosthetist is critical. Surgical steps are exposure, bone-end and canal preparation, first implant insertion (in the operative video shown, in the radius), purse-string muscle closure, confirmation that radius-ulna motion remains, performing the prior steps for the other bone (in the video, the ulna), and closure (including potential nerve reconstruction, soft-tissue contouring, and portal creation). Although the patient in the operative video did not require nerve procedures to address pain or to create targets for transcutaneous myoelectrodes, targeted muscle reinnervation or a regenerative peripheral nerve interface procedure could be performed following exposure. Alternatives: Alternatives include socket modification, bone lengthening and/or soft-tissue contouring13, Krukenberg-type reconstructions14, or accepting the situation. An alternative implant is a screw-type osseointegration implant. Our preference for press-fit implants is based on considerations such as our practice's 12-year history of >1,000 PFOI surgeries; that the screw-type implant requires sufficient cortical thickness for the threads15, which is compromised in some patients; the lower cost per implant; that the procedure is performed in 1 instead of 2 surgical episodes15,16; and the documented suitability of press-fit implants for patients with challenging anatomy or comorbidities17-19. Rationale: PFOI can be provided for amputees having difficulty with socket wear. PFOI usually provides superior prosthesis stability, which can confer better prosthesis control versus nonoperative and other operative options in patients expressing dissatisfaction for reasons such as those mentioned above, or for poor fit, compromised energy transfer, skin pinching, compression, and abrasions. For patients who want myoelectric control of their prosthesis but who are unable because the optimal myoelectric location is obstructed by the socket, osseointegration may provide access for the electrodes by eliminating the socket. Expected Outcomes: Only 3 trans-forearm osseointegration20-22 publications totaling 10 limbs could be identified, limiting the ability to determine generalizable outcomes. Osseointegrated prostheses, being skeletally anchored, feel lighter to patients than SPs, which should confer better outcomes. In 1 patient, multiple implant fractures and infection prompted additional surgeries. Periprosthetic bone fractures and non-infectious loosening have not been documented for UL osseointegration. Important Tips: Osseointegration eliminates the socket, relieving socket-based pain. However, neurogenic pain relief requires specific nerve procedures.Osseointegration provides a prosthesis connection. Nerve- or muscle-based prosthesis control requires separate, potentially integrated planning.Osseointegrated prostheses confer osseoperception (i.e., mechanical force transmission), not "normal" skin-mediated afferent sensation (i.e., light touch, temperature, pain) or native proprioception.Prostheses must be individualized to the patient's elbow flexion and radioulnar rotation. An attentive prosthetist must be ensured preoperatively.Achieving the demonstrated outcomes requires more therapy and retraining than walking with an osseointegrated lower-extremity prosthesis. Patients must expect at least several months of spending multiple hours daily engaging in self-directed rehabilitation.Prosthesis utilization decision aids23 may minimize non-beneficial surgeries. Acronyms and Abbreviations: UL = upper limbSP = socket prosthesisPFOI = press-fit osseointegrationperi-pros fx = periprosthetic fractureMRI = magnetic resonance imagingCT = computed tomography.

Bone mineral density in osseointegration implant surgery: A review of current studies (Review).

Osseointegration implant (OI) surgery is the latest rehabilitation technology for amputees, where a bone-anchored implant obviates the limitations of traditional socket prostheses. The bone mineral density (BMD) in the periprosthetic and other anatomical regions can be used to assess bone remodelling following OI surgery. Currently, limited studies have used BMD measurements in reporting post-operative OI outcomes and the association between the maintenance of BMD and implant efficacy has remained elusive. This review captured and analysed all studies that have reported the BMD as an objective outcome measure in patients with trans-femoral or trans-tibial OI. The PubMed, Medline, Scopus and Web of Science databases were searched using the terms 'amputation', 'osseointegration' and 'bone mineral density'. A total of 6 studies involving human participants were included for analysis. All studies used dual X-ray absorptiometry and/or X-rays for measuring BMD. Rehabilitation of trans-femoral or trans-tibial amputation using OI may help restore healthy BMD by enabling physiological bone loading. However, there is a low correlation between the BMD around the OI and the success of OI surgery or the risk of periprosthetic fractures. This review summarises the current evidence on BMD assessment in OI for lower limb amputee rehabilitation. Despite the great variability in the results, the available evidence suggests that OI may help restore BMD following surgery. The limited evidence calls for further investigation, as well as the development of a standard BMD measurement protocol.

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.

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.

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.

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.

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.

Total Hip Arthroplasty by the Direct Anterior Approach Using a Neck-preserving Stem: Safety, efficacy and learning curve.

BACKGROUND: The concept of femoral neck preservation in total hip replacement (THR) was introduced in 1993. It is postulated that retaining cortical bone of the femoral neck offers triplanar stability, uniform stress distribution, and accommodates physiological anteversion. However, data on safety, efficacy and learning curve are lacking. MATERIALS AND METHODS: We prospectively assessed all patients who were operated for a THR with a short neck preserving stem (MiniHip) between 2012 and 2014. The safety and learning curve were assessed by recording operative time; stem size; and adverse events including periprosthetic fracture; paresthesia; and limb length discrepancy (LLD). The cohort was divided into equal groups to assess the learning curve effect, and the cumulative sums (CUSUM) test was performed to monitor intraoperative neck fractures. For assessment of efficacy, Oxford Hip Score (OHS) and Short Form-36 (SF-36) scores were compared preoperatively and postoperatively. RESULTS: 138 patients with median age 62 years (range 35-82 years) were included with a median followup of 42 months (range 30-56 months). The minimum followup was 2.5 years. The OHS, SF-36 (physical and mental component) scores improved by a mean score of 26, 28, and 27 points, respectively. All patients had LLD of <10 mm (1.9 mm ± 1.3). Adverse events included intraoperative neck fracture (n = 6), subsidence (n = 1), periprosthetic fracture (n = 1), paresthesia (n = 12), and trochanteric bursitis (n = 2). After early modification of the technique to use a smaller finishing broach, the CUSUM test demonstrated acceptable intraoperative neck fracture risk. The second surgery group had a reduced risk of intraoperative neck fracture (5/69 vs. 1/69 P = 0.2), reduced operative time (66 vs. 61 min, P = 0.06), and increased stem size (5 vs. 6, P = 0.09) although these differences were not statistically significant. CONCLUSIONS: The MiniHip stem is safe alternative to standard THR with good functional outcomes but with a learning curve for the surgical technique, implants sizing, and the risk of intraoperative neck fractures.

Osseointegration as Treatment for a Knee Disarticulation Because of a Congenital Femoral Deficiency: A Case Report.

CASE: A 25-year-old woman underwent osseointegration surgery as treatment for an amputation that had been performed because of congenital femoral deficiency. The undersized custom-designed implant for the congenitally hypoplastic femur subsequently loosened, causing substantial pain and loss of function. The patient underwent revision surgery with a larger standard-sized osseointegration implant, and experienced no additional complications. CONCLUSION: This case demonstrates the possibility of stimulating a hypertrophic response in underdeveloped bone, which allows the subsequent insertion of a larger implant with greater stability. Similar procedures can be considered for the treatment of patients who had amputations because of congenital deficiencies, in order to produce improved outcomes and reduce the risk of additional complications.

Osseointegrated Transtibial Implants in Patients with Peripheral Vascular Disease: A Multicenter Case Series of 5 Patients with 1-Year Follow-up.

BACKGROUND: Osseointegration is an alternative treatment for amputees who are unable to wear or have difficulty wearing a socket prosthesis. Although the majority of limb amputations are due to vascular disease, such amputations have been perceived as a contraindication to osseointegration surgery. We report the outcomes of osseointegrated reconstruction in a series of 5 patients with limb amputation due to peripheral vascular disease. METHODS: Five patients with transtibial amputation and a history of peripheral vascular disease who received an osseointegration implant from 2014 to 2015 were followed for 12 months. Clinical and functional outcomes were assessed, including pain, the amount of time the patient wore the prosthesis, mobility, walking ability, and quality of life. Adverse events, including infection, fracture, implant failure, revision surgery, additional amputation, and death, were monitored and recorded. RESULTS: Five transtibial amputees (56 to 84 years of age) followed for 1 year after osseointegration surgery were included in this case series. The mobility of all patients was improved at the time of follow-up. Three patients were wheelchair-bound prior to the surgery but all 5 were able to walk and perform daily activities at the time of follow-up. Four of the 5 patients were pain-free at 12 months postoperatively, and all 5 were using the osseointegrated prosthesis. Two patients had a single episode of superficial soft-tissue infection. CONCLUSIONS: An osseointegrated implant may be considered a feasible alternative to the conventional socket prosthesis for patients with peripheral vascular disease. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Single-stage osseointegrated reconstruction and rehabilitation of lower limb amputees: the Osseointegration Group of Australia Accelerated Protocol-2 (OGAAP-2) for a prospective cohort study.

INTRODUCTION: Lower limb amputations have detrimental influences on the quality of life, function and body image of the affected patients. Following amputation, prolonged rehabilitation is required for patients to be fitted with traditional socket prostheses, and many patients experience symptomatic socket-residuum interface problems which lead to reduced prosthetic use and quality of life. Osseointegration has recently emerged as a novel approach for the reconstruction of amputated limbs, which overcomes many of the socket-related problems by directly attaching the prosthesis to the skeletal residuum. To date, the vast majority of osseointegration procedures worldwide have been performed in 2 stages, which require at least 4 months and up to 18 months for the completion of reconstruction and rehabilitation from the time of the initial surgery. The current prospective cohort study evaluates the safety and efficacy of a single-stage osseointegration procedure performed under the Osseointegration Group of Australia Accelerated Protocol-2 (OGAAP-2), which dramatically reduces the time of recovery to ∼3-6 weeks. METHODS AND ANALYSIS: The inclusion criteria for osseointegrated reconstruction under the OGAAP-2 procedure are age over 18 years, unilateral transfemoral amputation and experiencing problems or difficulties in using socket prostheses. All patients receive osseointegrated implants which are press-fitted into the residual bone. Functional and quality-of-life outcome measures are recorded preoperatively and at defined postoperative follow-up intervals up to 2 years. Postoperative adverse events are also recorded. The preoperative and postoperative values are compared for each outcome measure, and the benefits and harms of the single-stage OGAAP-2 procedure will be compared with the results obtained using a previously employed 2-stage procedure. ETHICS AND DISSEMINATION: This study has received ethics approval from the University of Notre Dame, Sydney, Australia (014153S). The study outcomes will be disseminated by publications in peer-reviewed academic journals and presentations at relevant clinical and orthopaedic conferences.

Osseointegrated Prosthetic Limb for the treatment of lower limb amputations : Experience and outcomes.

BACKGROUND: Osseointegration has emerged over the past two decades as a dramatically different approach for the treatment of lower limb amputations, which involves direct attachment of the prosthesis to the skeletal residuum. This approach can address many of the socket-interface issues associated with socket prostheses which represent the current standard of care for amputees. The Osseointegrated Prosthetic Limb (OPL) is an osseointegration implant with a new design and improved features compared to other available implant systems. OBJECTIVES: To report on the experience and outcomes of using the OPL for osseointegrated reconstruction of lower limb amputations. MATERIALS AND METHODS: This is a retrospective study of 22 patients who received the OPL implant between December 2013 and November 2014. Clinical outcomes were obtained pre- and post-operatively, with results reported at the 1­year follow-up. 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), and Timed Up and Go (TUG). Adverse events were also recorded. RESULTS: Compared to the mean pre-operative values obtained while patients were using socket prostheses or were wheelchair-bound, the mean post-operative values for all four validated outcome measures were significantly improved. There were 15 episodes of minor infections in 12 patients, all of which responded to antibiotics. Soft tissue refashioning was performed electively on 6 patients. No other adverse events were recorded. CONCLUSIONS: The results demonstrate that osseointegration surgery using the OPL is a relatively safe and effective procedure for the reconstruction and rehabilitation of lower limb amputees.

19 years outcome after cementless total hip arthroplasty with spongy metal structured implants in patients younger than 65 years.

BACKGROUND: Cementless fixation of total hip arthroplasties (THAs) is often favored in young, high-demanding patients due to the conservation of valuable bone-stock and easier revision if loosening has occurred. Long-term outcome data of the spongy metal structured implant used in the present study in patients younger than 65 years are still lacking. METHODS: We conducted a retrospective chart review and functional investigation (Merle d'Aubigné score, SF-12) of patients younger than 65 years at implantation treated with a spongy metal structured THA (n = 79) from one orthopedic university center from 1985 to 1989. RESULTS: At a 19-year mean follow-up (range: 15.3 - 21.3 years), the overall stem survival rate was 93.7 %, and the overall cup survival rate was 82.3 %. Revision surgeries of the stem were performed in all cases for aseptic loosening at an average of 15.3 ± 3.5 years after implantation. Acetabular components were revised for aseptic loosening and recurrent dislocation after inlay revision on an average of 11.8 ± 4.7 years after implantation. No other device related complications occurred within the 19-year follow-up period. No correlation was found between time of revision and gender or age. Clinical outcome scores (Merle d'Aubigné score, SF-12) revealed excellent to good results of the implanted THAs in 87 % of patients. CONCLUSIONS: We conclude that spongy metal structured cementless THAs implanted in young patients have an excellent survival and provide trustworthy clinical results at 19 years of follow-up.

Safety of Osseointegrated Implants for Transfemoral Amputees: A Two-Center Prospective Cohort Study.

BACKGROUND: Osseointegrated implants are an alternative for prosthetic attachment for individuals unable to wear a socket following an amputation. The concept of an integrated metal implant communicating with the external environment raises substantial concern about the risk of ascending infection. We report on the safety of press-fit osseointegrated implants currently used in Australia and the Netherlands. METHODS: We prospectively recorded all adverse events in all patients with transfemoral amputation who were managed with an osseointegration implant system between 2009 and 2013 at two centers. The procedure was performed in two stages. A customized porous-coated implant was placed in the first stage, and a stoma was created in the second. Adverse events were categorized according to type (infection or "other") and severity. Infections were classified according to four grades of severity based on clinical and radiographic findings: (1) low-grade soft-tissue infection, (2) high-grade soft-tissue infection, (3) bone infection, and (4) septic implant failure. RESULTS: Eighty-six patients (ninety-one implants), twenty-five to eighty-one years of age, were included in the study and followed for a median of thirty-four months (range, twenty-four to seventy-one months). Thirty-one patients had an uneventful course with no complications; twenty-nine developed infection (all grade 1 or 2); and twenty-six did not develop infection but had one or more other complications requiring intervention, including stoma hypergranulation (seventeen patients), soft-tissue redundancy (fourteen), proximal femoral fracture (three), inadequate osseointegration leading to implant replacement (one), implant breakage (two), and breakage of the pin used as a fail-safe mechanism (twenty-five). CONCLUSIONS: Mild infection and irritation of the soft tissue in the skin-penetration area are common in transfemoral amputees who have an osseointegrated implant. These complications were successfully managed with simple measures. Severe infections resulting in septic implant loosening are rare. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.