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

Transtibial osseointegration following unilateral traumatic amputation: An observational study of patients with at least two years follow-up

IMPORTANCE

Most patients use a traditional socket prosthesis (TSP) to ambulate independently following transtibial amputation. However, these patients generally require prosthesis repairs more than twice annually and an entirely new prosthesis every two years. Furthermore, transtibial amputation patients have four times the skin ulceration rate of transfemoral patients, prompting more frequent prosthesis refitting and diminished use. Trans-Tibial osseointegration (TTOI) is a promising technique to address the limitations of TSP, but remains understudied with only four cohorts totaling 41 total procedures reported previously. Continued concerns regarding the risk of infection and questions as to functional capacity postoperatively have slowed adoption of TTOI worldwide.

OBJECTIVE

This study reports the changes in mobility, quality of life (QOL), and the safety profile of the largest described cohort of patients with unilateral TTOI following traumatic amputation.

DESIGN

Retrospective observational cohort study. The cohort consisted of patients with data outcomes collected before and after osseointegration intervention.

SETTING

A large, tertiary referral, major metropolitan center.

PARTICIPANTS

Twenty-one skeletally mature adults who had failed socket prosthesis rehabilitation, with at least two years of post-osseointegration follow-up.

MAIN OUTCOMES AND MEASURES

Mobility was evaluated by K-level, Timed Up and Go (TUG), and Six Minute Walk Test (6MWT). QOL was assessed by survey: daily prosthesis wear hours, prosthesis problem experience, general contentment with prosthesis, and Short Form 36 (SF36). Adverse events included any relevant unplanned surgery such as for infection, fracture, implant loosening, or implant failure.

RESULTS

All patients demonstrated statistically significant improvement post osseointegration surgery with respect to K-level, TUG, 6MWT, prosthesis wear hours, prosthesis problem experience, general prosthesis contentment score, and SF36 Physical Component Score (p < 0.01 for all). Three patients had four unplanned surgeries: two soft tissue refashionings, and one soft tissue debridement followed eventually by implant removal. No deaths, postoperative systemic complications, more proximal amputations, or periprosthetic fractures occurred.

CONCLUSIONS AND RELEVANCE

TTOI is likely to confer mobility and QOL improvements to patients dissatisfied with TSP rehabilitation following unilateral traumatic transtibial amputation. Adverse events are relatively infrequent and not further disabling. Judicious use of TTOI seems reasonable for properly selected patients.

LEVEL OF EVIDENCE

2 (Therapeutic investigation, Observational study with dramatic effect).

Bone-anchored prostheses for transfemoral amputation: a systematic review of outcomes, complications, patient experiences, and cost-effectiveness

Introduction

Bone-anchored prostheses (BAP) are an advanced reconstructive surgical approach for individuals who had transfemoral amputation and are unable to use the conventional socket-suspension systems for their prostheses. Access to this technology has been limited in part due to the lag between the start of a new procedure and the availability of evidence that is required before making decisions about widespread provision. This systematic review presents as a single resource up-to-date information on aspects most relevant to decision makers, i.e., clinical efficacy, safety parameters, patient experiences, and health economic outcomes of this technology.

Methods

A systematic search of the literature was conducted by an information specialist in PubMed, MEDLINE, Embase, CINAHL, Cochrane Library, the Core Collection of Web of Science, CADTH's Grey Matters, and Google Scholar up until May 31, 2023. Peer-reviewed original research articles on the outcomes of clinical effectiveness (health-related quality of life, mobility, and prosthesis usage), complications and adverse events, patient experiences, and health economic outcomes were included. The quality of the studies was assessed using the Oxford Centre for Evidence-Based Medicine Levels of Evidence and ROBINS-I, as appropriate.

Results

Fifty studies met the inclusion criteria, of which 12 were excluded. Thirty-eight studies were finally included in this review, of which 21 reported on clinical outcomes and complications, 9 case series and 1 cohort study focused specifically on complications and adverse events, and 2 and 5 qualitative studies reported on patient experience and health economic assessments, respectively. The most common study design is a single-arm trial (pre-/post-intervention design) with varying lengths of follow-up.

Discussion

The clinical efficacy of this technology is evident in selected populations. Overall, patients reported increased health-related quality of life, mobility, and prosthesis usage post-intervention. The most common complication is a superficial or soft-tissue infection, and more serious complications are rare. Patient-reported experiences have generally been positive. Evidence indicates that bone-anchored implants for prosthesis fixation are cost-effective for those individuals who face significant challenges in using socket-suspension systems, although they may offer no additional advantage to those who are functioning well with their socket-suspended prostheses.

Transcutaneous osseointegration for amputees

Transcutaneous osseointegration for amputees (TOFA) is an evolving technology that has the potential to revolutionize the interface between the amputee and their prosthesis, showing potential at many levels of amputation. While no amputation is without its challenges, TOFA requires a highly specialized prosthesis and a multidisciplinary team that includes specialized surgeons, physical therapists, wound care teams, and social workers who guide the amputee through surgery, postoperative rehabilitation, and the chronic wound care that goes into maintaining the prosthesis. The infrastructure required to facilitate care pathways that lead to reliable, successful outcomes are unique in each health care setting, including those in advanced health care systems such as the United States and Australia. This article details the emerging evidence supporting the use of this prosthetic interface design and many of the challenges that providers face when establishing programs to offer this type of care in the United States.

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.

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.

Horrifying Basal Cell Carcinoma Presenting as Progressive Pyoderma Gangrenosum: Case Report

Introduction

Skin ulcers can be challenging to diagnose and manage, particularly with comorbid autoimmune and gastrointestinal diseases. Occam's razor encourages the simplest explanation to guide care, but reconsideration must occur when intervention proves futile.

Case Presentation

We report the case of a 70-year-old male, with a 17-year history of expanding pretibial skin ulcer, presumed by prior care providers to be pyoderma gangrenosum related to Crohn's disease. A surgical biopsy performed upon presentation to our institution revealed basal cell carcinoma of the skin, invasive to the proximal tibia with associated deep infection, prompting transfemoral amputation.

Conclusion

This report is written as a reminder to reconsider a diagnosis and consider seeking additional expertise when a patient's condition progressively worsens despite intervention. Earlier diagnosis likely would have facilitated therapeutic limb salvage care.

Limb sparing in a cat with a humeral osteosarcoma using a customised three-dimensional printed endoprosthesis

Case summary

A 12-year-old male neutered Bengal cat presented for a left thoracic limb lameness of several weeks' duration. Abnormal advanced imaging findings depicted the presence of an irregularly marginated osteolytic lesion in the proximal-mid diaphysis of the left humerus. A histopathological evaluation of the humerus confirmed a diagnosis of osteoblastic osteosarcoma. Limb-sparing surgery was planned with a custom-designed three-dimensional printed endoprosthesis. Mild neuropraxia was noted immediately postoperatively and deemed to have resolved by the 2-week follow-up. Stereotactic radiation was planned, though pulmonary metastasis was noted on planning CT. The cat was euthanased 90 days postoperatively owing to the development of pulmonary clinical signs.

Relevance and novel information

This is the first reported case of a humeral limb salvage procedure in a cat using a custom-designed three-dimensional printed endoprosthesis. Although the survival time in this case was short, the patient maintained an adequate quality of life and limb function was preserved.

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.