A Prospective Evaluation for a Possible Safe Skin Bridge in Elective Foot Surgery.

Background: In foot and ankle surgery, adequate surgical exposure often requires multiple incisions to be used near one another, thus creating a skin bridge. As the skin bridge becomes narrower, the wound edge vitality is potentially compromised and therefore the wound's ability to heal. The impact of local, host, and surgical factors on wound healing are well documented in the literature; however, little is known about the role of the skin bridge. The aim of this study is to determine if there is a recommendable safe skin bridge in elective foot and ankle surgery. Methods: A prospective study was performed on 56 patients with 60 feet who had elective foot surgery. The length of each incision and distance between the incisions were recorded. The wounds were assessed for complications at 2, 4, and 6 weeks after surgery. Patient demographics and host risk factors were documented. Results: The average incision length was 5.5 (range: 3-8.5) cm. The average skin bridge was 3.9 (range: 2-6.8) cm. Five (8.3%) of the 60 feet developed a wound complication. Four (80%) of these patients had a known comorbidity. Two patients had diabetes and 2 were smokers. The incidence of relevant comorbidities was 5.5% (n = 3) for patients without a wound complication (P < .001). Age did not differ significantly between patients with and without a wound complication. Patients with a wound complication had significantly longer incision lengths (P = .047). There was no significant independent association between skin bridge width and risk of wound complications (P > .05) with skin bridge widths of 2 cm or larger. Conclusion: In this relatively small cohort of 60 elective operative foot surgeries, we did not find increased wound complications in skin bridges 2 cm or larger, when meticulous surgical technique is practiced and host risk factors are optimized. Level of Evidence: Level III, prospective case control study.

Outcomes of Total Ankle Arthroplasty After Periprosthetic Cyst Curettage and Bone Grafting.

Total ankle arthroplasty (TAA) has become a popular management option for ankle arthritis. Periprosthetic osteolysis is one of the most common causes for reoperation in TAA. A CT scan should be done in all suspected osteolysis cases to confirm location, quantify size and aid in surgical planning. These patients are often asymptomatic with limited evidence regarding appropriate management. Smaller lesions should be monitored for progression in size. Periprosthetic cysts measuring 10-15mm in all three axes should be considered for debridment and curettage with autogenous bone grafting. The authors believe that bone grafting of large asymptomatic periprosthetic cysts could prevent implant failure.

Mathematical optimization of waste management systems: Methodological review and perspectives for application.

The transition to a circular economy through sustainable waste management (WM) follows different paths in each region, depending on its socioeconomic conditions and existing infrastructure. Mathematical optimization models are rigorous tools for informing local decision-making and identifying WM policy levers based on a variety of configurations. This review explores the pathways taken when designing WM optimization models (WM-OMs) that establish a network of waste valorization technologies. To standardize the literature review process, we propose a novel characterization method for examining, relating, and benchmarking the features of WM-OMs. After a thorough review of 58 articles published between 2015 and 2022, we assembled a comprehensive database to document the characteristics of these papers and the type of data reported in their case studies. We aim to provide a solid foundation for streamlining and enhancing future WM-OMs. Our work identifies various opportunities to improve the accuracy and reliability of WM-OMs. They include modeling thermo-chemical reactions in WM processes; considering regulatory, environmental, and political constraints; recognizing the informal sector; exploring the impact of marketing mechanisms on waste prevention and recycling; improving the traceability of case study data; specifying the rationale for uncertainty analysis (UA); and indicating the mathematical model (type, optimization algorithm, and equations). As many WM-OM authors have implemented UA without justifying their method choices, our review provides a pioneering guide for selecting the UA approach. Finally, we discuss the need for a trade-off between performance and practicality as models become more complex, making it critical to consider the specific needs of stakeholders.

The use of a 3D printed titanium implant for arthrodesis in the management of large osseous defects in the ankle.

BACKGROUND: Large osseous defects (LOD) in the ankle occur because of multiple aetiologies. Advancement in 3-dimensional (3D) printing technologies has led to the use of custom implants and instrumentation their management. A 3D printed patient-specific porous titanium cage which allows for peripheral osteo-integration and autogenous bone-grafting could be an ideal implant in these cases. METHODS: Retrospective review of a multi-centre, multi-surgeon consecutive cohort of patients requiring either TTC or AA for a large osseous defect between June 2019 - August 2020. A custom titanium prosthesis was 3D-printed according to CT measurements for implantation. RESULTS: Mean follow up was 19.5 months (range 12-24 months). Plain radiographs and CT scans at 12 months confirmed osseointegration (stability) in 11of 13 patients (84%). Two patients developed late infection, one requiring revision surgery. CONCLUSIONS: 3D-Printed titanium implants in the management of LODs in the ankle offer a comparable success rate to other reported procedures, with unlimited geometric possibilities in the design allowing for accurate length correction. Their structural stability may offer an advantage over conventional bone graft techniques and limits the amount of bone-graft required. LEVELS OF EVIDENCE: LOE III.

A Novel Domain Knowledge-Informed Machine Learning Approach for Modeling Solid Waste Management Systems.

Sustainability challenges, such as solid waste management, are usually scientifically complex and data scarce, which makes them not amenable to science-based analytical forms or data-intensive learning paradigms. Deep integration between data science and sustainability science in highly complementary manners offers new opportunities for tackling these conundrums. This study develops a novel hybrid neural network (HNN) model that imposes the holistic decision-making context of solid waste management systems (SWMS) on a traditional neural network (NN) architecture. Equipped with adaptable hybridization designs of hand-crafted model structure, constrained or predetermined parameters, and a customized loss function, the HNN model is capable of learning various technical, economic, and social aspects of SWMS from a small and heterogeneous data set. In comparison, the versatile HNN model not only outperforms traditional NN models in convergence rates, which leads to a 22% lower mean testing error of 0.20, but also offers superior interpretability. The HNN model is capable of generating insights into the enabling factors, policy interventions, and driving forces of SWMS, laying a solid foundation for data-driven decision making.

Foot and Ankle Injuries in Elite South African Cricketers: A Descriptive Analysis of Injury Surveillance Data.

Introduction: Injury surveillance is an important part of injury risk reduction in the sporting population. This study describes the type, side (dominant or non-dominant), occurrence, impact, activity of onset, and severity of foot and ankle injuries in elite South African male and female cricketers. Methods: Foot and ankle injuries sustained by elite cricket players between 2018 and 2021, obtained from the records of Cricket South Africa, were descriptively analysed. Results: A total of 104 foot and ankle injuries in 82 players were recorded. The majority (n = 100; 96%) of injuries were on the non-dominant side. Bowling (n = 31; 30%) and fielding (n = 20; 19%) contributed to most injuries. The majority were first-time (n = 83; 80%) and non-impact injuries (n = 62; 60%). Fifty percent (n = 52) of injuries rendered players unable to participate in at least one match or practice session. Lateral ankle ligament injury was the most common injury sustained (n = 36; 35%). Conclusion: The findings from this study can inform future researchers and assist healthcare service needs relating to injury risk reduction and management programmes. Effective rehabilitation programmes may reduce the risk of reinjury. Ideally, these programmes need to be role specific.

Tumor induced osteomalacia from a peripheral mesenchymal tumour of the foot.

Tumour induced osteomalacia (TIO) is a rare condition caused by peripheral mesenchymal tumours (PMT) which produce fibroblast-growth factor 23 (FGF23). FGF23 inhibits renal phosphate reabsorption leading to vitamin D resistant osteomalacia. The rarity of the condition and difficulty with isolating the PMT make diagnosis difficult, with delayed treatment leading to significant patient morbidity. We present a case of PMT of the foot with TIO, with a discussion on diagnosis and treatment.

Patient reported outcomes following revision neurectomy through a dorsal approach for recurrent interdigital neuroma.

Interdigital neuroma is one of the commonest causes of metatarsalgia. The reported success rate after excision of a primary neuroma is 74%. Recurrent symptoms after neurectomy can be due to a recurrent interdigital neuroma. Recurrent interdigital neuromas can be diagnosed using sound clinical examination and ultrasonography. Surgical excision is the best treatment modality with varying success reported in the literature. We report on the clinical outcome following surgical excision of recurrent interdigital neuromas through a dorsal approach. All patients who had undergone excision of a recurrent interdigital neuroma by a single surgeon between 01/2010 and 12/2019 were identified. Inclusion criteria included patients having a preoperative ultrasound and postoperative histology report. The exclusion criteria were preexisting neuropathy or tarsal tunnel syndrome. Demographic data was collected, and a self-reported foot and ankle score questionnaire (SEFAS) was completed by the patient at their most recent follow-up. Twenty-three patients (25 feet) were included in the study. Mean time of follow-up was 75 (range 14-189) months. The mean age was 49 (range 15-71) years. Eleven (44%) recurrent neuromas were excised from the second webspace and 14 (56%) were excised from the third webspace. All excised masses were confirmed as recurrent neuromas histologically. Regarding the SEFAS score, 17 (73.93%) patients scored as excellent, one (4.34%) as good, three (13.04%) as fair, and two (8.69%) as poor. This long term follow-up study on outcomes after surgery for recurrent interdigital neuroma suggests that excision through a dorsal approach is an effective treatment option with a high patient satisfaction.

A Rare Case of Flexor Digitorum Accessorius Longus Muscle Presenting as Tarsal Tunnel Syndrome.

Tarsal tunnel syndrome (TTS) is a relatively uncommon nerve entrapment neuropathy. Many pathologies are reported as possible causes for TTS. The diagnosis of TTS can be difficult and often missed. We present a rare case of TTS due to an accessory flexor digitorum longus muscle. Together with a high index of suspicion, MRI is the investigation of choice in making the diagnosis. These patients are best managed with excision or transposition of the flexor digitorum accessorius longus (FDAL) and neurolysis of the posterior tibial nerve and its branches.

CT Scan Assessment and Functional Outcome of Periprosthetic Bone Grafting After Total Ankle Arthroplasty at Medium-term Follow-up.

BACKGROUND: Periprosthetic cysts can occur in up to 95% of total ankle arthroplasties (TAA) and have been correlated with implant failure. The aim of this study was to determine the clinical and radiologic outcomes, using computed tomographic (CT) scan, after periprosthetic cyst bone grafting and assess for the minimum cyst size that should be grafted. METHODS: A retrospective review was performed of all TAA procedures performed between 2007 and 2014 (n=93). A CT scan was done to assess cyst size and operative planning. Eight patients with 9 periprosthetic cysts larger than 1.75 cm3 were grafted and specimens sent for histology. The mean time to bone grafting was 7.3 (3.8-9.5) years. Functional outcome was assessed using the American Orthopaedic Foot & Ankle Society ankle score, visual analog scale, and Self-reported Foot and Ankle Score. A CT scan was performed at follow-up to assess graft incorporation and cyst size progression. The mean time to CT scan post grafting was 3.0 (0.7-4.7) years. RESULTS: There was no implant malalignment identified and no differences in the pre- and postoperative functional scores. Preoperatively cysts had a mean volume of 8.16 (2.04-14.03) cm3. The mean percentage incorporation was 89% (69%-100%). Eight of the grafted cysts were considered successful on CT, with the ninth having 69% incorporation. Five cysts were not grafted, as they were below 1.75 cm3, and remained the same size or had minimal enlargement. CONCLUSION: The satisfactory results in this small cohort suggests that prophylactic bone grafting may extend implant survival. We recommend that periprosthetic cysts greater than 1.75 cm3 be prophylactically bone grafted, and that cysts smaller than 1.75 cm3 be monitored for progression in size. LEVEL OF EVIDENCE: Level IV, Case Series.

Reliability of the Radiographic Measurement of the Hallux Interphalangeal Angle.

BACKGROUND: The hallux valgus interphalangeus (HVI) deformity has a common association with hallux valgus and hallux rigidus. The HVI is formed by the angle between the long axes of the proximal and distal phalanges. The normal value for this angular deformity in the coronal plane is less than 10°. The aim of this study was to analyze the intra- and inter-observer reliability of measuring the interphalangeal angle by orthopaedic surgeons. This study is the first study to evaluate specifically the reliability and reproducibility of measuring the HVI angle. METHODS: Twenty-one X-ray prints of weightbearing feet constituted a set. Sixteen qualified orthopaedic surgeons were asked to measure the HVI angle of all 21 X-ray images in the set. Three randomized sets were sent to each evaluator at 4-week intervals. After all 3 sets were measured, data were retrieved and statistically analyzed to determine the inter- and intraobserver variability and reliability in the measurement of the HVI angle. Reproducibility of the HVI measurement was assessed using 3 categories, which included the ability to measure the same angle 3 times and achieve: 3° or less, 5° or less, and more than 5° variation. RESULTS: The intraobserver reliability was found to be 5° or less in 85.2% of participants and the interobserver reliability was 81.2%. The researcher did not find significant correlation between the surgeons' level of experience with regard to the reliability of measuring the HVI angle. CONCLUSION: The inter- and intraobserver reliabilities of measuring the HVI angle is 81.2% and 85.2%, respectively. The level of experience of the surgeon does not improve this reliability. LEVELS OF EVIDENCE: Level II.

Knee scooter related injuries and satisfaction in patients following foot and ankle surgery.

BACKGROUND: Knee scooters have become popular amongst foot and ankle surgeons for patients who are required to be non-weight bearing. Information is limited regarding falls and injuries sustained while using a knee scooter and potential contraindications to their use are ill-defined. No study has assessed patient reported injuries and satisfaction. This study aims to evaluates the patient's perspective with regards to the use of a knee scooter. As a secondary aim we assessed for risk factors associated with knee scooter related injuries to try make recommendations for the safe use of a knee scooter. METHODS: Patients who used a knee scooter during 2018-2020 were emailed a questionnaire assessing (1) demographic data, (2) medical history, (3) falls and injuries sustained, including the management of these injuries, and (4) patient satisfaction. This study is a descriptive, cross-sectional survey analysis. RESULTS: 101/196 (51,5%) responses were received, which included 32 males and 69 females. The cohort had a mean age of 56.4 years, and BMI of 28.5. Mean time spent using the scooter was 6.7 weeks. Twenty-five respondents had fallen off the scooter, with 5 reporting injuries. One patient required medical attention for a shoulder injury. Cause of falls included hitting an obstacle, making a sharp turn, moving too fast, and moving downhill. There was no correlation between falls and patient comorbidities. Ninety-six percent of respondents reported a high satisfaction and preferred the scooter to crutches. CONCLUSION: The knee scooter is a safe, and well-tolerated, mobility aid for patients requiring non-weight bearing during their recovery, with a high satisfaction rate. Educating patients on correct use and common causes for falling is important as a preventative measure. LEVEL OF EVIDENCE: IV, retrospective case series.

A new lesser metatarsophalangeal joint replacement arthroplasty design - in vitro and cadaver studies.

BACKGROUND: Isolated degenerative joint disease and/or Freiberg's infraction of the lesser metatarsophalangeal joint, although not frequent may become debilitating in the younger individual. Currently, once conservative management fails, the mainstay of treatment is debridement and excision-interposition arthroplasty. Replacement arthroplasty has been ineffective in the long term as the joints are subject to severe repetitive fatigue loading over small articulating surfaces through a wide range of motion. This is an in vitro and cadaver study of a new design replacement arthroplasty developed by the senior author. The aim of this study is to evaluate this novel replacement arthroplasty of the lesser metatarsophalangeal joint in a laboratory setting and cadaver implantation. METHODS: This three-component mobile bearing device is made of titanium and high density polyethylene which evolved over 4 years. It was subjected to 5,000,000 cycles in a laboratory under physiological and excessive forces to assess resistance to fatigue failure and wear pattern of the polyethylene liner. Following these tests, it was implanted in 15 fresh frozen cadavers at various stages of its development, during which the surgical technique was perfected. Range of motion and stability was tested using custom made instrumentation in four cadavers. The implant was inserted in a further two cadavers by an independent foot and ankle surgeon to check reproducibility. RESULTS: The device showed almost no signs of wear or surface deformation under physiological forces. The surgical technique was found to be simple and reproducible in the cadaver trial. The average dorsiflexion was 28.5° and 28.9° pre- and post-implant respectively. The average plantar flexion was 33.8° and 20.8° pre- and post- implant respectively. The joints were stable both pre- and post-operatively. Post-operative stability was objectively assessed for dorsal displacement and dorsiflexion using a 5 kgf (49 N) and was found to be excellent. CONCLUSION: This novel lesser metatarsophalangeal joint replacement arthroplasty has been developed as an option in the surgical treatment of symptomatic degenerative joint disease and/or Freiberg's infraction resistant to conservative treatment. The implant was found to be durable and resistant to wear in the laboratory testing. The cadaver studies have shown it to require minimal specialized instrumentation with good surgical reproducibility. This proof of concept study is the basis for clinical trials.

Outcomes of bilateral simultaneous hallux MTPJ fusion.

BACKGROUND: Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a frequently performed surgical procedure. Many patients have bilateral hallux MTPJ pathology requiring bilateral arthrodesis. There are concerns that bilateral simultaneous hallux surgery, under one anaesthetic, results in the patient being severely incapacitated in the early post-operative period. We hypothesize that bilateral simultaneous hallux MTPJ fusions does not compromise outcomes or the patients' post-operative comfort and rehabilitation and is cost and time effective. METHODS: In this retrospective study, 16 patients who underwent bilateral simultaneous first MTPJ arthrodesis were compared to 16 patients who had unilateral MTPJ arthrodesis with regards to outcome, tolerance, cost and time effectiveness. Outcome measures were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux score and the Self-Reported Foot and Ankle questionnaire (SEFAS). RESULTS: There was a significant improvement in the AOFAS scores post surgery in the bilateral group and according to the SEFAS grading, 14 patients (87.5%) had good or excellent outcome scores with 13 (81.25%) of these patients having excellent scores. This was comparable to the outcome scores in the unilateral group. Two patients developed non-unions bilaterally compared to one in the unilateral group. There is also a notable general cost saving and less time off work when bilateral fusions are done at the same setting. CONCLUSION: Bilateral simultaneous hallux MTPJ arthrodesis is an effective, convenient and cost effective option for patients requiring MTPJ fusions for bilateral hallux pathology. LEVEL OF EVIDENCE: Level 4.

Comparison of 2 Oblique Fifth Metatarsal Osteotomies for the Management of a Bunionette.

BACKGROUND: A bunionette is a painful prominence of the fifth metatarsal head. This study aimed to compare the clinical outcome of 2 corrective osteotomies, namely, the Mau-type and Ludloff-type osteotomies. We report results with regard to correction, healing, complications, and patient-reported outcomes. METHODS: Thirty-two patients who underwent bunionette corrective surgery from March 2011 to May 2017 were included in the study. All patients had pre- and postoperative radiographs. The pre- and postoperative fourth-fifth intermetatarsal angles (IMAs) and postoperative fifth metatarsal bowing angle were measured. Radiographic union was assessed at 12 weeks. All patients completed the Self-Reported Foot and Ankle Score (SEFAS) questionnaire to assess clinical outcome. Thirty-two patients (43 feet) were available for follow-up and completed the SEFAS score. Twenty-two Mau-type and 21 Ludloff-type osteotomies were performed. RESULTS: The mean pre- and postoperative IMA for Mau was 10.5 and 4.3 degrees, respectively, and for the Ludloff was 10.2 and 4 degrees, respectively, with no statistically significant difference between the 2 groups. The Mau caused more bowing with a mean of 9.8 degrees as compared to a mean of 3.5 degrees with the Ludloff. No patients in the Mau group reported clinical problems related to the increased bowing. All osteotomies united. The Mau cohort had a mean SEFAS score of 45 and the Ludloff cohort a mean of 46. No feet had fair or poor outcome scores. CONCLUSION: Patient satisfaction after bunionette correction with an oblique shaft rotational osteotomy was good. Orientation of the osteotomy did not affect outcomes. Postoperative bowing of the fifth metatarsal was greater with the Mau-type osteotomy. Postoperative fifth metatarsal bowing had no negative clinical effects. The trend in our unit has been a preference toward the Mau-type osteotomy as it is perceived to be more stable. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Radiographic Assessment of Relative First Metatarsal Length Following Modified Lapidus Procedure.

BACKGROUND: The modified Lapidus is a surgical procedure for managing moderate to severe hallux valgus, especially in the presence of first tarsometatarsal joint arthritis or hypermobility. It has good long-term results but reportedly can lead to transfer metatarsalgia due to inherent shortening of the first metatarsal. METHODS: A retrospective analysis of all adult patients who underwent a modified Lapidus procedure during a 3-year period was performed. Clinical notes were evaluated to look for nonunion or any other complications related to the surgery. Pre- and postoperative standard weightbearing radiographs were used to establish the relative metatarsal length (RML), intermetatarsal angle (IMA), hallux valgus angle (HVA), and distal metatarsal articular angle (DMMA). A total of 69 modified Lapidus procedures were identified, with 32 included in the study. RESULTS: The mean pre- and postoperative RMLs were -0.8 and -4.9 mm, respectively. The average RML shortening due to the procedure was -4.1 (P < .0001). The mean pre- and postoperative IMAs were 15 and 5 degrees, respectively (P < .0001). The mean pre- and postoperative HVAs were 33 and 9 degrees, respectively (P < .0001). One patient reported transfer metatarsalgia, which was attributed to elevation of the first metatarsal. CONCLUSION: We found a statistically significant degree of shortening of the relative length of the first metatarsal without any clinically significant metatarsalgia. The low rate of transfer metatarsalgia following the modified Lapidus procedure could be attributed to the sagittal plane correction and stability obtained by performing a first tarsometatarsal fusion. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Morphology of the first metatarsal head as a risk factor for hallux valgus interphalangeus.

BACKGROUND: The aetiology of hallux valgus interphalangeus (HVI) is not well understood. First metatarsophalangeal joint stability, influenced by first metatarsal head shape, may be linked to HVI. We hypothesised that first metatarsal head shape is a risk factor for HVI. No published article could be found in the literature investigating this hypothesis. METHODS: 127 standardised foot radiographs were analysed retrospectively. The hallux valgus angle (HVA) and interphalangeus angle (IPA) were measured. The first metatarsal head shape was divided into chevron, round and flat groups. Statistical analysis was then performed to investigate the relationship between first metatarsal head shape and the occurrence of HVI. RESULTS: There was no statistically significant relationship between first metatarsal head shape and the occurrence of HVI. There was however a negative relationship between HVA and HVI. CONCLUSIONS: The morphology of the first metatarsal head does not seem to be a risk factor for HVI. A known negative relationship between HVA and IPA is reinforced. LEVEL OF EVIDENCE: Level III, retrospective cohort.

Economics of materials in mobile phone preprocessing, focus on non-printed circuit board materials.

Incomplete recovery of materials in mobile phones results in a significant economic loss. Many studies have focused on improving the situation by characterizing metals within printed circuit boards (PCBs) to identify where losses occur. Our work focuses on the evolving composition of mobile phones and particularly the flow of materials located within components outside of PCBs. In this study we quantify the appreciable economic potential of non-PCB derived metals and provide suggestions for optimization of different preprocessing steps to recover these materials. These opportunities can be categorized as recovering both high value and high volume materials. We therefore recommend that preprocessors pay special attention to precious metals in fine shredding and develop strategies for plastics recycling based on our demand and supply forecasts of postconsumer plastics in phones. We have performed this work based on a case study of Portugal.