BADAL X Safety and Effectiveness

Safety

Chronic bacterial colonization of the transcutaneous component of bone anchoring systems for artificial limbs is inevitable since the device penetrates through the skin and is exposed to the extracorporeal environment. Bone anchoring systems are therefore associated with frequent, but relatively mild, soft tissue infections in the skin penetration area in the first months after implantation. These soft tissue infections are causally not associated with septic loosening of the bone anchoring system because septic loosening is an exceptional complication. Aseptic loosening also rarely occurs and is associated with insufficient osseointegration capacity or wrong sizing of the intramedullary component. These complications will need carefully weighed against the potential benefits regarding function and quality of life in the risk-benefit profile. On the benefit side, literature consistently reports increased prosthetic use (78-80%), longer walking distance in the six minutes walking test (32%), better quality of life (62-73%), less energy consumption during walking (18%) (Van de Meent et al Arch Phys Med Rehab 2013). On the risks side it is obvious that the transcutaneous attachment causes superficial pin tract infections with pain (12-13%), typically managed by local wound care and/or oral antibiotics. Deep infections and/or removal of the implant of press fit bone anchoring systems due to infection seldom occurs. Other noninfectious complications such as fractures of the femur, implant loosening, mechanical complications with the abutment and implant breakages may occur. However, the bone anchoring devices have been subject to radical improvements in design, surgical technique and rehabilitation protocols, in the past two decades. This has resulted in much lower rates of complications. It is assumed that BADAL X is now the most elaborate bone anchoring system with respect to implant design and instructions for use. Several specific patient risk factors for implant failure have been identified and are implemented in the BADAL X exclusion criteria and instructions for use. 
 

Clinical trial with BADAL X (Attalah et al Plos One 2020)

Safety and effectiveness of BADAL X was investigated in 91 consecutive individuals who underwent BADAL X treatment between March 2015 and June 2018 in a single center in the Netherlands and were followed-up for 12 months (Attalah et al. Plos One, 2020). Ninety subjects of the 91 subjects were eligible, including 66 with transfemoral amputation (3 bilateral), 3  through knee, and 21 with transtibial amputation (1 bilateral). The average age was 54 years (range 20-86) and 26 subjects were females. The cause of amputation was trauma; n=49, vascular; n=12, infection; n=11, oncology; n=8, congenital; n=2, miscellaneous; n=8. 

Three patients were lost to follow-up, one patient with an OTI developed a progressive ischemic vascular disease and underwent transfemoral amputation and two participants (one with OTI and one with OFI-C did not attend the clinic at 1 year follow-up due to reasons unrelated to the BAP. Of the 94 implanted BADAL X devices the number OFI-C, OFI-Y, and OTI implants was 55, 17 and 22 respectively.
 

Results: general/device unrelated adverse events

One individual developed a progressive ischemic peripheral vascular disease after BADAL X surgery resulting in a higher (transfemoral) amputation. Other reported adverse events included; pulmonary embolism after stage 1 OFI-C implantation (n-1). One patient (OFI-C) developed transient nausea, hypertension and pain at 5 months after OI surgery but these complaints disappeared suddenly and inexplicable with few minor adaptations of the alignment of the artificial limb. Two individuals had bone fractures, one hip neck fracture after a fall (OFP-C) which was treated successfully with dynamic hip screw osteosynthesis and one lumbar vertebra fracture after a fall (OFP-C) which was treated conservatively.
 

Results: BADAL X related adverse events:

Prevalence of implant loosening was reported 0%. Prevalence of soft tissue infection requiring surgical refashioning was reported 2%; two individuals required surgical treatment, due to stoma irritation caused by redundant soft tissue and for peri-stoma abscess drainage respectively. Prevalence of implant breakage was reported 0%. Prevalence of implant revision rate/failure rate was reported 0%, therefore, implant survival rate was 100%. Four breakages of the adapter (double conus adapter) of BADAL X occurred. Three subjects (two with OFI-Y and one with OTI) had a breakage of the Adapter distal taper and one subject with OFI-C had broken weakpoints of the Adapter. All broken Adapters were successfully replaced in an outpatient clinic setting. The cause of the broken distal Adapter taper was investigated and it was identified that the taper breakage was caused bij a mis-fit between taper and male part of the connector. In line with the corrective and preventive action procedure of the BADAL X manufacturer OTN Implants, two new connectors; HELI and LUCI were designed, manufactured and tested according to the ISO 10328. 

Twelve of the 90 individuals (13%) developed a grade 1 soft tissue infection and eleven individuals (12%) developed grade 2 soft tissue infection. All grade 1 and 2 soft tissue infections were pin-track infections and occurred in the first months after BADAL X surgery. All grade 1 infections were successfully treated with oral antibiotics (grade 1A). Grade 2 infections were treated successfully with oral antibiotics in 9 cases (grade 2A). Four individuals that underwent two stage BADAL X surgery experienced wound infections after stage 1 and therefore, step two of the surgery was performed earlier. The number of soft tissue infections related to OFI-C, OFI-Y and OTI were: 8, 5, and 10 respectively. Correcting for the differences in numbers per group by using the above mentioned infection/implant-year ratio this amounts to a ratio of 15.1 ((8 infections/53 implants with 1 year follow-up)x100), 31.3 ((5/16)x100) and 47.6 ((10/21)x100) for the OFI-C, OFI-Y, and OTI respectively. Other reported probably device related adverse events were: transient knee pain after OTI (n=1), transient groin pain after OFI-C (n=1), and distal femoral heterotopic bone formation (OFI-C) in one patient that used Aclasta intravenously for the treatment of glucocorticoid-induced osteoporosis.
 

Results: BADAL X performance:

Device related quality of life as measured with the Q-TFA Global Score improved 78% with BADAL X as compared to pre-operative values with the socket attached artificial limb. Prosthetic use improved 73% as compared to pre-operative values.
 

Conclusion

The transcutaneous bone anchoring systems for artificial limbs are inevitably connected with device related pin tract complications and these complications will need carefully weighed against the potential benefits regarding function and quality of life in the risk-benefit profile. On the benefit side, literature consistently reports improved functional mobility, physical performance, and physical health. On the risks side it is obvious that the transcutaneous attachment causes superficial pin tract infections, typically managed by local wound care and/or oral antibiotics. Deep infections and/or removal of the implant of press fit bone anchoring systems due to infection seldom occurs. Other noninfectious complications such as fractures of the femur, implant loosening, mechanical complications with the abutment and implant breakages may occur. However, the bone anchoring devices have been subject to radical improvements in design, surgical technique and rehabilitation protocols, in the past two decades. This has resulted in much lower rates of complications. BADAL X is now the most elaborate bone anchoring system with respect to implant design and instructions for use. Several specific patient risk factors for implant failure have been identified and are implemented in the BADAL X exclusion criteria and instructions for use. Evidence is shown in the recent one year follow up results of 94 implanted BADAL X systems which showed pin tract grade 1 and 2 complications rates of respectively 13% and 12% compared to a quality of life improvement of 78%. 
 

BADAL X Disclosure of residual risk (provided in the IFU)

  • General risks associated with anesthesia and major surgery; 
  • Cardiovascular complications including deep vein thrombosis, thrombophlebitis, pulmonary embolism, wound hematoma and avascular necrosis; 
  • Nerve damage, neuromas;
  • Intra-osseous lesion, including fissures, perforations, peri-prosthetic fractures or stem removal; 
  • Abnormal stump pain (acute, chronic, psychosomatic); 
  • Heterotopic ossification; 
  • Bacterial colonization of the stoma or soft tissue area with or without signs or symptoms of infection; 
  • Complications in the stoma area including edema, swelling, tissue irritation including delay of the stoma epithelialisation; 
  • Superficial infections of the stoma and / or soft tissue; 
  • Deep intramedullary infections, osteitis, osteomyelitis, septic arthritis; 
  • Muscle contractures, enthesitis, tendinitis;
  • Loosening, fracture, or mechanical failure of prosthetic components due to excessive load (excessive physical activity, sport, inattention or contraindications) or non-physiological stress (fall and / or traumatic accidents) or due to incorrect choice of components (eg, improper size of stem and transcutaneous adapter);
  • Falling in case of breakage of the prosthetic components;
  • Possible excessive tension on the soft tissues of the stump as skin, scars or muscles;
  • Peri-prosthetic bone resorption and bone loss, osteonecrosis; 
  • Retrograde stem migration; 
  • Lack or insufficient osseointegration of the intramedullary stem with the subsequent loosening, due to e.g.poor bone quality, inadequate primary stability (press fit), micro-movements, early mobilization and loading; 
  • Allergic reaction to the implant materials or the emission of metal ions by the implant; 
  • Complications due to modular prosthetic connections (metallosis, adverse biological reactions, osteolysis due to particles and release of metal ions due to corrosion, abrasion and wear component interface) 
  • Revision surgery to replace one or more parts before the end of its useful life; 
  • Revision surgery for a permanent explant of BADAL X implant; 
  • Revision surgery with amputation of the stump at a higher (more proximal) level; 
  • Detection by security surveillance systems based on electromagnetic fields and interference with clinical analysis or instrumental analyses based on magnetic fields;