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

Aims. Prior cost-effectiveness analyses on osseointegrated prosthesis for transfemoral unilateral amputees have analyzed outcomes in non-USA countries using generic quality of life instruments, which may not be appropriate when evaluating disease-specific quality of life. These prior analyses have also focused only on patients who had failed a socket-based prosthesis. The aim of the current study is to use a disease-specific quality of life instrument, which can more accurately reflect a patient’s quality of life with this condition in order to evaluate cost-effectiveness, examining both treatment-naïve and socket refractory patients. Methods. Lifetime Markov models were developed evaluating active healthy middle-aged male amputees. Costs of the prostheses, associated complications, use/non-use, and annual costs of arthroplasty parts and service for both a socket and osseointegrated (OPRA) prosthesis were included. Effectiveness was evaluated using the questionnaire for persons with a transfemoral amputation (Q-TFA) until death. All costs and Q-TFA were discounted at 3% annually. Sensitivity analyses on those cost variables which affected a change in treatment (OPRA to socket, or socket to OPRA) were evaluated to determine threshold values. Incremental cost-effectiveness ratios (ICERs) were calculated. Results. For treatment-naïve patients, the lifetime ICER for OPRA was $279/quality-adjusted life-year (QALY). For treatment-refractory patients the ICER was $273/QALY. In sensitivity analysis, the variable thresholds that would affect a change in the course of treatment based on cost (from socket to OPRA), included the following for the treatment-naïve group: yearly replacement components for socket > $8,511; cost yearly replacement parts OPRA < $1,758; and for treatment-refractory group: yearly replacement component for socket of > $12,467. Conclusion. The use of the OPRA prosthesis in physically active transfemoral amputees should be considered as a cost-effective alternative in both treatment-naïve and treatment-refractory socket prosthesis patients. Disease-specific quality of life assessments such as Q-TFA are more sensitive when evaluating cost-effectiveness. Cite this article: Bone Jt Open 2024;5(3):218–226

Observing a decreasing number of transfemoral amputations following infection of Total Knee Arthroplasty (TKA) we performed a retrospective case control study of all rehabilitated amputees in the HELIOS centre of rehabilitation for amputees, located in Bad Berleburg, Germany. This study examines all patients who had undertaken a transfemoral amputation (TF) after infection of TKA since 2007. Methods: retrospective case control study. The clinical reports of 355 patients with transfemoral amputation rehabilitated from 2007 to 2013 were systematically and statistically evaluated. In this period we rehabilitate 636 amputees. Results: 9 patients – 2.53% of all TF-amputations suffered a loss of the lower extremity caused by an infection of TKA. 3 patients presented an infection only by MRSA (multiresistant Staph. aureus 33.33%), 2 patients only with MSSA (multisensible Staph. aureus); other 4 patients presented mixed infections with MRSE (multiresistant Staph. epidermidis), multiresistant Acinetobacter baumannii, E. coli, Enterococcus faecalis, Pseudomonas aeroguinosa. Epidemiology: The mean age of the patients at time of amputation was 70.07 years, with 4 men and 5 women. Marital status: 6 patients are married (66.66%), 1 divorced, 1 widowed, 1 unmarried. All patients are retired. School-leaving qualifications: 7 elementary school (60.87%), 1 secondary school, 1 unknown. Health insurance: AOK 3 patients (33.33%), BKK 3 patients (33.33%), employers insurance 1 patients (11.11%) and 2 more patients. The medial time of hospitalization in the clinic for rehabilitation after suffering amputation because of infection of TKA was 29.22 days. Mobility class of amputees at the beginning of hospitalization: class 0 (= non walkers) all 9 patients (100%). Mobility class of amputees at the end of hospitalization: class 0 (= non walkers) are 2 patients (22.22%), class 1 (= walking only inside) are 5 patients (55.55%), class 2 (= walking inside and a little outside) are 2 patients (22.22%), class 3 (= walking well inside and outside) no patient. This retrospective case control study shows for the first time that amputation of the lower extremity following infection in TKA is rare – in our group we found 2.53%. In the national and international literature one does not find much research about transfemoral amputations caused by infection in TKA. In our clinic we notice a decreasing number

Noting a decreasing number of transfemoral amputations following infection of Total Knee Arthroplasty (TKA) I studied a case of a patient which suffered an amputation following infection of TKA by MRSA. With assistance of all hospitals and the NHS it was able to classify all costs of this poor case. This study exposes a drama of a person which received a Total Knee Arthroplasty in the right knee at 66.0 years. 2 weeks after the implantation of TKA she presented a wound secretion, the microbiology shows: MRSA, Pseudomonas aeroguinos and Streptococcus. 4 surgical revisions followed without removing the TKA. 35 month later, with 68.9 years it was indispensable to remove the TKA in a 6th operation, implanting a spacer with Vancomycine. 1 month later removing of the spacer and implanting a second cemented TKA in the 7th surgery. With 70.2 years the removal of the second TKA was necessary because of infection with Pseudomonas aeroguinosa and Morganelli morganii. Now implantation of another spacer with Vancomycine. 1 month later with 70.3 years removal of the spacer molding an arthrodesis of the knee using an intramedullary femur to tibia rod. After that 4 revision surgeries with changing the intramedullary rod some wound revisions followed, ending in the 23rd operation with a transfemoral amputation with 71.1 years – 5 years after primary TKA. 3 month after transfemoral amputation the patient presented high temperature and a secretion of the scarf of the TT-stump; microbiology: MRSA. 2 more surgeries are necessary to stop the infection. This patient suffered over all 25 surgical procedures in 5.5 years. The hospitalization for acute infection of TKA led to 431 days in different hospitals in 33 months. Statement of charges from the hospitals € 74.046,92 in the last three years before amputation. Payments by the health insurance € 155.424,00 for all procedures. We will demonstrate the different costs of hospital procedures and distribution for the insurance for all performances

Aims. The aim of this study was to compare the cost-effectiveness of treatment with an osseointegrated percutaneous (OI-) prosthesis and a socket-suspended (S-) prosthesis for patients with a transfemoral amputation. Patients and Methods. A Markov model was developed to estimate the medical costs and changes in quality-adjusted life-years (QALYs) attributable to treatment of unilateral transfemoral amputation over a projected period of 20 years from a healthcare perspective. Data were collected alongside a prospective clinical study of 51 patients followed for two years. Results. OI-prostheses had an incremental cost per QALY gained of €83 374 compared with S-prostheses. The clinical improvement seen with OI-prostheses was reflected in QALYs gained. Results were most sensitive to the utility value for both treatment arms. The impact of an annual decline in utility values of 1%, 2%, and 3%, for patients with S-prostheses resulted in a cost per QALY gained of €37 020, €24 662, and €18 952, respectively, over 20 years. Conclusion. From a healthcare perspective, treatment with an OI-prosthesis results in improved quality of life at a relatively high cost compared with that for S-prosthesis. When patients treated with S-prostheses had a decline in quality of life over time, the cost per QALY gained by OI-prosthesis treatment was considerably reduced. Cite this article: Bone Joint J 2018;100-B:527–34

Rates of prosthetic joint infection in megaprostheses are high. The application of silver ion coating to implants serves as a deterrent to infection and biofilm formation. A retrospective review was performed of all silver-coated MUTARS endoprosthetic reconstructions (SC-EPR) by a single Orthopaedic Oncology Surgeon. We examined the rate of component revision due to infection and the rate of infection successfully treated with antibiotic therapy. We reviewed overall revision rates, sub-categorised into the Henderson groupings for endoprosthesis modes of failure (Type 1 soft tissue failure, Type 2 aseptic loosening, Type 3 Structural failure, Type 4 Infection, Type 5 tumour progression). 283 silver-coated MUTARS endoprosthetic reconstructions were performed for 229 patients from October 2012 to July 2022. The average age at time of surgery was 58.9 years and 53% of our cohort were males. 154 (71.3%) patients underwent SC-EPR for oncological reconstruction and 32 (14.8%) for reconstruction for bone loss following prosthetic joint infection(s). Proximal femur SC-EPR (82) and distal femur (90) were the most common procedures. This cohort had an overall revision rate of 21.2% (60/283 cases). Component revisions were most commonly due to Type 4 infection (19 cases), Type 2 aseptic loosening/culture negative disease (15 cases), and Type 1 dislocation/soft tissue (12 cases). Component revision rate for infection was 6.7% (19 cases). 15 underwent exchange of implants and 4 underwent transfemoral amputation due to recalcitrant infection and failure of soft tissue coverage. This equates to a limb salvage rate of 98.3%. The most common causative organisms remain staphylococcus species (47%) and polymicrobial infections (40%). We expand on the existing literature advocating for the use of silver-coated endoprosthetic reconstructions. We provide insights from the vast experience of a single surgeon when addressing patients with oncological and bone loss-related complex reconstruction problems

A retrospective case control study of all rehabilitated patients who suffered amputations of the lower extremity by sepsis was performed in the HELIOS centre of rehabilitation for amputees, Bad Berleburg, Germany. This study examines patients who had undertaken an amputation of the lower extremity caused by severe sepsis and septic shock. Methods: Case control study. The clinical reports of 448 patients with amputations of the lower extremity clinically rehabilitated from 2010 to 2013 were systematically and statistically evaluated. Sepsis is classified in 4 categories: SIRS, sepsis, severe sepsis and septic shock. Epidemiology: The mean age of the amputees was 61.33 years, with 25 men and 11 women. Marital status: 16 patients are married (44.44%), 7 divorced, 5 widowed, 7 unmarried, 1 unknown. 24 patients are retired (66.67%). School-leaving qualifications: 22 elementary school (61.11%), 8 secondary school, 1 high school, 5 unknown. Health insurance: AOK 10 patients (27.77%), BEK 7 patients (19.44%), pension insurance 9 patients (25.0%). The medial time of hospitalization in the clinic for rehabilitation of the amputated patients suffering sepsis was 27.23 days. Results: 36 patients, – 8.03 % of all – with 39 amputations, suffered a loss of the lower extremity caused by severe sepsis and septic shock: 1 patient suffered an exarticulation of both hips, 20 patients suffered a transfemoral amputation (1 patient had a transfemoral amputation of both legs), 17 patients lost their leg by transtibial amputation (1 patient had a transtibial amputation of both legs). 13 patients presented a sepsis by MRSA (multiresistant Staph. aureus 36.11%), 8 patients with MSSA (multisensible Staph. aureus), 4 patients with multiresistant Acinetobacter (8.33%), 2 patients with MRSE (multiresistant Staph. epidermidis), 13 patients with other multiresistant germs (36.11%) such as Streptococcus B, Enterococcus faecalis, Enterobacteriaceae, Klebsiella. Mobility class of amputees at the beginning of hospitalization: class 0 (= non walkers) all 36 patients (100%). Mobility class of amputees at the end of hospitalization: class 0 (= non walkers) are 5 patients (27.78%), class 1 (= only inside walkers) are 5 patients (13.89%), class 2 (= inside and little outside walkers) are 18 patients (50.00%), class 3 (= inside and good outside walkers) are 3 patients (8.33%). Amputation of the lower extremity following severe sepsis and septic shock is not rare – in our group we found more than 8%

This study aimed to characterise severe open femoral fractures sustained by military personnel and to describe their orthopaedic management and preliminary outcomes. The UK Military Trauma Registry was searched for open femoral fractures sustained between 2006–2010. Clinical records and radiographs were reviewed and data gathered on demographics, injury, management and preliminary outcomes. Thirty-four patients with 34 open femoral fractures were eligible for inclusion. The mean NISS was 22.4 (SD 12.28). Nineteen fractures were caused by gunshot wounds (56%), with the remainder due to blasts. Three patients (9%) suffered Grade 4 segmental bone loss. Intramedullary nailing was used in 22 patients (69%). A minimum of 12 month follow up was available for 33 patients (97%). Twenty-three patients (70%) had achieved fracture union within the first twelve months. One patient suffered deep infection requiring surgical debridement. Ten patients (30%) underwent a revision procedure due to femoral shortening or malunion: two required a transfemoral amputation. There was a significant association between bone loss and a poor outcome (revision surgery) at 12 months (p=0.00016). Infection rates were significantly lower in open femoral fractures when compared to similar published work on open tibial fractures (p=0.0257)

Aim. The first osseointegrated transfemoral amputation prosthesis operation was performed in Gothenburg in 1990. The aim is improving quality of life for patients who cannot use conventional socket prosthesis. In 1999 the prospective OPRA-study (Osseointegrated Prosthesis for Rehabiliation of Amputees) was initiated with standardized surgery, equipment and rehabilitation program. Method. The surgery consists of a two-stage procedure. At the primary surgery (S1), a titanium screw (the fixture) is inserted into the remaining diaphyseal bone. The fixture is 80 mm long with a diameter of 16–20 mm (+0.5 mm increments). The patient is hospitalized 5-7 days. At the secondary surgery (S2), six months later, an abutment is inserted into the fixture. The abutment has a hexagonal press-fitting into the fixture and is secured by an abutment screw. The patient remains hospitalized 10–12 days. Gradual increase of load and activity is initiated over a 6 month period. Results. The OPRA study includes 51 patients with 55 implants. Follow-up time has been set to minimum 2 years. The OPRA study will be evaluated in June 2010. 32 of the 51 patients have been followed for 2 years or more. Four implants have been removed due to loosening/infection. No patient has been lost to follow-up. Preliminary data shows that the success rate so far is 93% (51/55). Conclusion. Development of this new concept has to be carefully monitored and controlled. Once a standard technique was developed a drop in the complication rate was noted. Although deep infection and fixture loosening is the most feared complication, so far the most encountered one is late deformation of the abutment due to overload since the patients activity level is significantly increased caused by the good prosthetic function allowing the patient to use the prosthesis 12–15 hours daily, 7 days a week

We retrospectively reviewed 19 femoral non-unions. Age group ranged from 17–72 yrs with mean of 40 yrs. 12 were men and 7 were women. 11 fractures involved diaphysis and 8 involved supracondylar area. 5 cases were infected non-unions. Time from fracture to defini-tive treatment varied from 5 to 88 months (mean 21 months). Open technique was used in 18 cases. In 8 cases we have used autogenous cancellous bone graft and in 3 cases BMP7 was used in addition to bone graft. 9 cases were treated with Ilizarov frame without bone graft, 6 with plate & bone graft, 3 with intramedullary nail and 1 with bone graft alone. Internal bone transport was carried out in 5 cases to achieve limb length equality. Fracture union was achieved in 16 patients with 7 excellent and 8 good results as per ASAMI criteria. 15 cases achieved excellent to good functional results. Because of persistent infection, 2 distal femoral non-unions required transfemoral amputation. Treatment was discontinued due to psychiatric illness in 1 patient with Ilizarov frame. Two of the patients in Supracondylar group developed knee stiffness. Pin tract infection is a common complication in Ilizarov group. Adequate reduction & stabilization is key to success. Non-unions without any complications can be treated with exchange nail or open reduction and plating. Ilizarov method is effective for non-unions complicated by distal location, infection and bone loss. Psychological assessment is important before considering Ilizarov method of treatment

Aim and methods: We present our results on the treatment an outcome of femoral non-unions in our institution as tertiary referral centre. Retrospective analysis was performed using the ASAMI criteria. Results: 19 patients, 12 men and 7 women were retrospectively assessed. Mean age was 40 years (range 17–72). 11 fractures were in the diaphysiseal area and 8 were in the supracondylar area. 5 cases were infected non-unions. Time from fracture to definitive treatment varied from 5 to 88 months (mean 21 months). Open technique was used in 18 cases. In 8 cases we have used autogenous cancellous bone graft and in 3 cases BMP7 was used in addition to bone graft. 9 cases were treated with Ilizarov frame without bone graft, 6 with plate and bone graft, 3 with intramedullary nail and 1 with bone graft alone. Internal bone transport was carried out in 5 cases to achieve limb length equality. Fracture union was achieved in 16 patients with 7 excellent and 8 good results as per ASAMI criteria. 15 cases achieved excellent to good functional results. Because of persistent infection, 2 distal femoral non-unions required transfemoral amputation. Treatment was discontinued due to psychiatric illness in 1 patient with Ilizarov frame. Two of the patients in supracondylar group developed knee stiffness. Pin tract infection is a common complication in Ilizarov group. Conclusion: Adequate reduction and stabilization is key to success. Non-unions without any complications can be treated with exchange nail or open reduction and plating. Ilizarov method is effective for non-unions complicated by distal location, infection and bone loss. Psychological assessment is important before considering Ilizarov method of treatment

Purpose. Rotationplasty was first described in 1930 by Borggreve for treatment of limb shortening with knee ankylosis after tuberculosis. In 1948, Van Nes described its use for management of congenital defects of the femur and in the 1980s, Kotz and Salzer reported on patients with malignant bone tumors around the knee treated by rotationplasty as an alternative to above-knee amputation. Currently, rotationplasty is one of the options for surgical management of lower extremity bone sarcomas in skeletally immature patients but alternative limb salvage techniques, such as the use of expandable endoprosthesis, are also available. Despite rather satisfactory functional results have been uniformly associated with rotationplasty, concern still exists about the potential psychological impact of the new body imagerelated to the strange appearance of the rotated limb. Results of rotationplasty for sarcomas of the distal femur over a 20-year period were analyzed, focusing on long-term survival, function, quality of life and mental health. Method. Retrospective study of 73 children who had a rotationplasty performed at two institutions between 1984 and 2007 for a bone sarcoma of the distal femur; 42 males and 31 females, mean age at surgery 8.7 yrs (range 3–17). Four patients were converted to transfemoral amputation due to early vascular complication; 25 eventually died of their disease (mean survival 34 months, range 4–127). The 46 remaining survivors were evaluated for updated clinical outcome, MSTS score, gait analysis, SF-36 score, quality of life interview and psychological assessment at mean follow-up of 15 yrs (range 3–23). Results. Overall survival was 64%. All the survivors were disease-free at last follow-up. Four patients required hardware revision for nonunion and subsequently healed. Three patients refused participation in the long-term follow-up study. Mean MSTS score was 79 (range 64–88). SF-36 score was obtained in 35 patients (age > 16); male patients showed a trend toward greater activity and vitality. Compared to age-group norms, rotationplasty scores were lower for physical activity level (p <0.05) and higher for general health perception (p = 0.05) and mental health (p < 0.05). Conclusion. Rotationplasty remains a durable reconstructive option with good long-term function and acceptable psychological impact for children with bone sarcomas of the distal femur

Introduction and Aims: Orthopaedic oncologists are often consulted regarding problems involving salvage of the distal femur due to bone loss, non-unions, infections. In young patients, extensive bony reconstruction is often necessary; in elderly, low demand patients, replacement with an endoprosthetic device results in decreased surgical time and more rapid mobilisation. Method: Since 1991, 27 patients underwent reconstruction with a custom modular distal femoral replacement and rotating hinged knee joint (DFR). Twenty-two (81%) were revised to a DFR from an existing knee arthroplasty. Diagnoses included fracture, non-union, osteomyelitis, osteolysis or deformity. Average age was 66 (25–85); 83% were female. Most patients had undergone multiple prior surgeries. Patients with a history of infection had undergone aggressive resection and insertion of spacers with prolonged antibiotic administration, however they had no infection at the time of DFR reconstruction. All endoprostheses were cemented. Patients were allowed immediate weight-bearing and rehabilitation similar to patients undergoing TKA. Results: One elderly patient died in the immediate peri-operative period of respiratory failure and one was lost to follow-up after placement in a nursing home. Average follow-up on 25 evaluable patients was 47 months (7–122). Reoperations were for recurrent infection (six) and tibial component loosening (three). Five of the six with infection were treated with synovectomy, antibiotic beads and suppressive oral antibiotics, and all five devices are still in place at an average of 54 months (range, 25–100). One severely diabetic patient had had multiple episodes of sepsis unrelated to the prosthesis which eventually seeded the distal femur and required a hip disarticulation. MSTS functional scores at last follow-up averaged 49% (13–80%) and HSS knee scores averaged 71% (37–90%). Conclusion: DFR is a useful salvage procedure in low demand patients. Initially, six patients were scheduled for transfemoral amputation and three were confined to wheelchairs. Patients other than the hip disarticulation were at minimum household ambulators at last follow-up. In spite of problems with infection, most patients improved in overall function

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.

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.

The December 2015 Oncology Roundup³⁶⁰ looks at: Amputation may not be the best option; Growing golf balls bad news!; How close is safe? Radiotherapy and surgery; Lymphocyte: monocyte ratio in osteosarcoma; Are borderline cartilage tumours really borderline?; Boosting algorithms improves survival estimates; CT better than Mirels?

Heterotopic ossification (HO) is perhaps the single most significant obstacle to independence, functional mobility, and return to duty for combat-injured veterans of Operation Enduring Freedom and Operation Iraqi Freedom. Recent research into the cause(s) of HO has been driven by a markedly higher prevalence seen in these wounded warriors than encountered in previous wars or following civilian trauma. To that end, research in both civilian and military laboratories continues to shed light onto the complex mechanisms behind HO formation, including systemic and wound specific factors, cell lineage, and neurogenic inflammation. Of particular interest, non-invasive in vivo testing using Raman spectroscopy may become a feasible modality for early detection, and a wound-specific model designed to detect the early gene transcript signatures associated with HO is being tested. Through a combined effort, the goals of early detection, risk stratification, and development of novel systemic and local prophylaxis may soon be attainable.