Value of Acid-Fast Bacilli and Fungal Cultures in Foot and Ankle Surgery in a US Hospital System.

BACKGROUND: Acid-fast bacilli(AFB) and fungi are generally slow-growing, difficult to culture, and rarely the cause of infection. The goal of this study was to evaluate the value of routinely obtaining AFB and fungal cultures in foot and ankle surgery at a US hospital. METHODS: A retrospective review was conducted to determine the number of positive AFB and fungal cultures out of the total number of foot and ankle samples tested. Between 2014 and 2019, patients who underwent surgery for a foot and ankle infection for soft tissue infection, septic arthritis, infectious postoperative complications were identified. Charts were reviewed to identify the results of the microbiological tests performed. To determine the value of running AFB and fungal cultures, the costs of each were provided by the microbiology lab at our institution. RESULTS: Of the 322 patient charts reviewed, there were 434 AFB and 525 fungal cultures performed. None of these cultures were indicated to be positive for AFB (0%), and 22 (4.19%) were positive for fungi. The total labor and material costs were calculated to be $38 767. The AFB cultures cost $23 967, the positive fungal cultures cost $2371, and the negative fungal cultures cost $36 395.36. CONCLUSION: This 322-case series of surgically managed foot and ankle infections showed 0% and 4.1% positivity rates of AFB and fungal cultures, respectively. Additionally, only 20% of cases with positive cultures were identified as pathologic requiring antifungal treatment. Further analysis is needed to determine best practices for obtaining vs declining to culture for AFB or fungal species, including assessing patient outcomes in the series of culture-positive(fungal-only) cases. Our results suggest that in our clinical setting of a US hospital system, routine fungal and AFB cultures may not be necessary but should be considered for chronic/recalcitrant infections, immunocompromised patients, and those with high surgeon suspicion. LEVEL OF EVIDENCE: Level IV, case series.

Tibial torsion correlates with talar morphology.

BACKGROUND: There is limited literature on axial rotation of the ankle or variations in anatomy of the talus. We aim to evaluate the rotational profile of the distal tibia and its relationship to talus morphology, radiographic foot-type, and tibiotalar tilt in arthritic ankles. METHODS: Preoperative imaging was reviewed in 173 consecutive patients with ankle arthritis. CT measurements were used to calculate tibial torsion and the talar neck-body angle (TNBA). Tibiotalar tilt and foot-type were measured on weightbearing plain radiographs. RESULTS: Measurements indicated mean external tibial torsion of 29.2±9.1˚ and TNBA of 35.2±7.5˚ medial. Tibiotalar tilt ranged from 48˚ varus to 23.5˚ valgus. A moderate association between increasing external tibial torsion and decreasing TNBA was found (ρ=-0.576, p<.0001). Weak relationships were found between external tibial torsion and varus tibiotalar tilt (ρ=-0.239, p=.014) and plantarflexion of the talo-first metatarsal angle (ρ=-0.218, p<.025). CONCLUSION: We observed a statistically significant correlation between tibial torsion and morphology of the talus, tibiotalar tilt, and first ray plantarflexion. This previously unreported association may provide information regarding the development of foot and ankle deformity and pathology. LEVEL OF EVIDENCE: Level III.

Local and Systemic In Vivo Responses to Osseointegrative Titanium Nanotube Surfaces.

Orthopedic implants requiring osseointegration are often surface modified; however, implants may shed these coatings and generate wear debris leading to complications. Titanium nanotubes (TiNT), a new surface treatment, may promote osseointegration. In this study, in vitro (rat marrow-derived bone marrow cell attachment and morphology) and in vivo (rat model of intramedullary fixation) experiments characterized local and systemic responses of two TiNT surface morphologies, aligned and trabecular, via animal and remote organ weight, metal ion, hematologic, and nondecalcified histologic analyses. In vitro experiments showed total adherent cells on trabecular and aligned TiNT surfaces were greater than control at 30 min and 4 h, and cells were smaller in diameter and more eccentric. Control animals gained more weight, on average; however, no animals met the institutional trigger for weight loss. No hematologic parameters (complete blood count with differential) were significantly different for TiNT groups vs. control. Inductively coupled plasma mass spectrometry (ICP-MS) showed greater aluminum levels in the lungs of the trabecular TiNT group than in those of the controls. Histologic analysis demonstrated no inflammatory infiltrate, cytotoxic, or necrotic conditions in proximity of K-wires. There were significantly fewer eosinophils/basophils and neutrophils in the distal region of trabecular TiNT-implanted femora; and, in the midshaft of aligned TiNT-implanted femora, there were significantly fewer foreign body giant/multinucleated cells and neutrophils, indicating a decreased immune response in aligned TiNT-implanted femora compared to controls.

Dimensions of the Lateral Malleolar Fossa and Its Potential Violation With Lateral Distal Fibular Plate Fixation.

A previously undescribed pitfall of lateral distal fibular locking plates is the risk of violating the lateral malleolar fossa (MF). No previous study has described the dimensions of this fossa. All cases using a lateral distal fibular plate for a fibula fracture from December 2012 to December 2015 (n=365) at a single institution were reviewed. Screws that violated the medial fibular cortical density corresponding to the MF were identified as "at-risk" screws. Available preoperative computed tomography (CT) scans were reviewed (n=69) to measure MF dimensions. Of 365 patients, 115 (31.5%) patients had distal fibular screws at risk of MF violation. There were no significant differences between MF violation and non-violation groups in terms of age, sex, open fracture, syndesmotic fixation, and Weber classification. The MF dimensions were measured on CT scans. Mean height was 12.96 mm (SD, 2.09 mm; range, 9.0-17.3 mm). Mean width was 7.52 mm (SD, 1.37 mm; range, 4.2-10.4 mm). Mean depth was 8.32 mm (SD, 1.59 mm; range, 5.3-11.8 mm). Mean ratio of MF to total fibular width was 0.46 mm (SD, 0.07 mm; range, 0.3-0.65 mm). Mean MF to total fibular depth was 0.42 mm (SD, 0.07 mm; range, 0.28-0.58 mm). There was a difference in dimensions of patients with screws at risk of MF violation compared with those without (MF height: 13.77 vs 12.56, P=.02; MF width: 7.98 vs 7.30, P=.05; MF to fibula width ratio: 0.49 vs 0.44, P=.01; MF to fibula depth ratio: 0.43 vs 0.42, P=.05). The MF violation is a previously unreported but potentially prevalent pitfall of lateral distal fibular plate fixation. Surgeons should be aware of the MF size and exhibit caution when placing screws in the distal locking holes during fibula fixation. [Orthopedics. 2020;43(3):e141-e146.].

Titania nanotube morphologies for osseointegration via models of in vitro osseointegrative potential and in vivo intramedullary fixation.

As total joint replacements increase annually, new strategies to attain solid bone-implant fixation are needed to increase implant survivorship. This study evaluated two morphologies of titania nanotubes (TiNT) in in vitro experiments and an in vivo rodent model of intramedullary fixation, to simulate joint arthroplasty conditions. TiNT surfaces were prepared via an electrochemical etching process, resulting in two different TiNT morphologies, an aligned structure with nanotubes in parallel and a trabecular bone-like structure. in vitro data showed bone marrow cell differentiation into osteoblasts as well as osteoblastic phenotypic behavior through 21 days. In vivo, both TiNT morphologies generated greater bone formation and bone-implant contact than control at 12 weeks, as indicated by µCT analyses and histology, respectively. TiNT groups also exhibited greater strength of fixation compared to controls, when subjected to wire pull-out testing. TiNT may be a promising surface modification for promoting osseointegration.

Revision of the Failed Ankle Fusion.

A failed ankle fusion is a complicated and not-uncommon occurrence. Successful management requires a thorough preoperative evaluation to determine the cause of initial clinical failure and identify surgical strategies to maximize the likelihood of clinical success. Because revision ankle fusion is a risk factor for failed ankle fusion, a measured approach is required. Patients typically fall into one of three categories. In patients without infection or substantial malalignment, clinical success can be achieved with a broad scope of surgical interventions tailored to the specific clinical symptoms of the patient. Patients with malalignment may require osteotomy for correction. The final group, encompassing patients with infection or bone loss, often requires a more complex approach. A measured, meticulous approach increases the likelihood of successful revision surgery and can decrease the likelihood of further surgery. Although revision is often successful, limb salvage may not be possible in a small subset of patients.

Effect of Bisphosphonate Pretreatment on Fresh Osteochondral Allografts: Analysis of In Vitro Graft Structure and In Vivo Osseous Incorporation.

Fresh allograft transplantation of osteochondral defects restores functional articular cartilage and subchondral bone; however, rapid loss of chondrocyte viability during storage and osteoclast-mediated bone resorption at the graft-host interface after transplantation negatively impact outcomes. The authors present a pilot study evaluating the in vitro and in vivo impact of augmenting storage media with bisphosphonates. Forty cylindrical osteochondral cores were harvested from femoral condyles of human cadaveric specimens and immersed in either standard storage media or storage media supplemented with nitrogenated or non-nitrogenated bisphosphonates. Maintenance of graft structure and chondrocyte viability were assessed at 3 time points. A miniature swine trochlear defect model was used to evaluate the influence of bisphosphonate-augmented storage media on in vivo incorporation of fresh osteochondral tissue, which was quantified via µCT and decalcified histology. In the in vitro study, Safranin-O/Fast Green staining showed that both low- and high-dose nitrogenated-treated grafts retained chondrocyte viability and cartilage matrix for up to 43 days of storage. Allografts stored in nitrogenated-augmented storage media showed both µCT and histologic evidence of enhanced in vivo bony and cartilaginous incorporation in the miniature swine trochlear defect model. Several preclinical studies have shown the potential for enhanced storage of fresh osteochondral allografts via additions of relatively common drugs and biomolecules. This study showed that supplementing standard storage media with nitrogenated bisphosphonates may improve maintenance of chondrocyte viability and graft structure during cold storage as well as enhance in vivo osseous and cartilaginous incorporation of the graft. [Orthopedics: 2018; 41(3):e376-e382.].

Single-Surgeon Experience and Complications of a Fixed-Bearing Total Ankle Arthroplasty.

BACKGROUND: Total ankle arthroplasty (TAA) has historically resulted in inferior survivorship rates compared with total hip and knee arthroplasty, because of technical issues unique to ankle anatomy. In this study, a single-surgeon series of intra- and postoperative complications as well as resultant reoperations/revisions of the Tornier Salto Talaris, a fixed-bearing TAA prosthesis, were reviewed. METHODS: Medical records from index procedure to latest follow-up of primary TAA were reviewed. Complications were categorized according to the Glazebrook classification; additional complications were documented. Concurrent procedures were recorded, and radiographs were analyzed for alignment, subsidence, and cyst formation. Time to complication onset and learning curve analyses were performed. One hundred four Salto Talaris TAA prostheses (96 patients), with an average follow-up of 46 months, were included. RESULTS: Thirty-five complications were identified in 32 ankles with a 34% complication rate, resulting in 11 reoperations (5 TAA revisions). Technical error (n = 12), wound healing (n = 9), and aseptic loosening (n = 4) were the most common complications, and there were no statistically significant differences in demographics or follow-up duration between cases with versus without complications. In both the cohorts with and without complications, there were moderate, negative correlations between radiographically observed keel osteopenia and lucency (ρ = -0.548, P = .00125, and ρ = -0.416, P = .000303, respectively); also, in the complication cohort, a weak, positive correlation between subsidence and lucency (ρ = 0.357, P = .0450) was found. CONCLUSION: Salto Talaris TAA survivorship and reoperation rates in our series were comparable with previous reports, using either the same or similar mobile-bearing prostheses; new information regarding complication, radiographic, and learning curve analyses was presented. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Review of Mechanical, Processing, and Immunologic Factors Associated With Outcomes of Fresh Osteochondral Allograft Transplantation of the Talus.

Osteochondral lesions of the talus (OLTs) are an increasingly implicated cause of ankle pain and instability. Several treatment methods exist with varying clinical outcomes. Due in part to successful osteochondral allografting (OCA) in other joints, such as the knee and shoulder, OCA has gained popularity as a treatment option, especially in the setting of large lesions. The clinical outcomes of talar OCA have been inconsistent relative to the positive results observed in other joints. Current literature regarding OCA failure focuses mainly on 3 factors: the effect of graft storage conditions on chondrocyte viability, graft/lesion size, and operative technique. Several preclinical studies have demonstrated the ability for bone and cartilage tissue to invoke an immune response, and a limited number of clinical studies have suggested that this response may have the potential to influence outcomes after transplantation. Further research is warranted to investigate the role of immunological mechanisms as an etiology of OCA failure. LEVEL OF EVIDENCE: Level V, expert opinion.

The midfoot is really deformed after hindfoot arthrodesis: how to salvage?

Concomitant hindfoot and midfoot deformity is common. Hindfoot fusion is associated with prolonged recovery and significant disability. Further surgery is often required to obtain a plantigrade foot. Understanding normal structural and kinematic relationships between the midfoot and hindfoot, as well as recognizing common combined patterns of midfoot and hindfoot deformity, can minimize the unanticipated consequences of hindfoot fusion. Treatment of residual or resultant midfoot deformity requires a thorough analysis of the deformity and familiarity with a variety of operative techniques for correction.

Missed peritalar injuries: an analysis of factors in cases of known delayed diagnosis and methods for improving identification.

UNLABELLED: Because of the complex anatomy of the foot, rarity of fractures of the foot, and subtle radiographic cues, foot injuries are commonly overlooked and mis/undiagnosed. This study seeks to investigate a patient population whose peritalar injuries, including fractures and dislocations, were missed on initial examination, in order to analyze factors of known, missed injuries and provide insight into methods for reducing the incidence of missed diagnoses. Surgical cases between January 1999 and May 2011 were queried and retrospectively reviewed to identify missed peritalar injuries. Of 1682 surgical cases reviewed, 27 patients with missed peritalar injury(ies), which were subsequently confirmed by imaging studies, were identified. Using the Orthopaedic Trauma Association classification, fracture and dislocation subtypes were classified. A medical record review was performed to assess demographic and surgical data elements. In this study population, 7 types of peritalar injuries (talus, calcaneal, navicular, and cuboid fractures as well as subtalar, calcaneocuboid, and talonavicular joint dislocations) were diagnosed in 27 patients. All patients required surgical intervention. Talus fractures were the most commonly missed injury. In patients with multiple peritalar injuries, there was a strong correlation between talus and navicular fractures (r = -0.60; P < .01) as well as a moderate correlation between talus fractures and calcaneocuboid dislocations (r = -0.46; P = .02). The presence of a calcaneal fracture significantly decreased the time to definitive diagnosis (P = .01). Male patients' diagnoses were delayed an average of 324 days and females 105 days (P = .04). A moderate correlation was found between patient age at injury and time to diagnosis (r = -0.47; P = .04), with a decreased time to diagnosis as patient age increased. Significant factors were identified in this patient population, including patient sex and age, which may contribute to missed or delayed diagnosis in the clinical setting. Prompt and accurate diagnosis of peritalar injuries may improve long-term outcomes. LEVELS OF EVIDENCE: Care Management, Level V.

The adult paralytic foot.

The adult paralytic foot is a common clinical entity. It has numerous neurologic, systemic, and traumatic causes that result in muscle imbalance and foot deformity. A thorough physical examination and diagnostic work-up, as well as an understanding of the relevant functional anatomy, are essential to proper management. Treatment goals include the establishment of a plantigrade foot, elimination of deforming forces, and, when possible, restoration of active motor control.

Functional results of posterior tibial tendon reconstruction, calcaneal osteotomy, and gastrocnemius recession.

BACKGROUND: This study aimed to assess and provide prospective outcome data following reconstruction of Stage II posterior tibial tendon insufficiency, as well as evaluate the effect of reconstruction with gastrocnemius recession on plantarflexion strength. METHODS: A prospective evaluation of 24 patients undergoing reconstruction for Stage II posterior tibial tendon insufficiency was granted IRB approval. The reconstructive procedures consisted of a flexor digitorum longus transfer, medial displacement calcaneal osteotomy, lateral column lengthening, and gastrocnemius recession. Patients were asked to complete multiple outcome measures preoperatively, 6 months, 1 year, and 2 years postoperatively. A dynamometer was utilized to evaluate peak torque plantarflexion preoperatively, 6 months, and 1 year postoperatively. RESULTS: In the study, 14 patients completed preoperative surveys, and 23 patients had 2-year followup. Patients were highly satisfied with the results of their surgery. All outcome measures showed statistically significant improvement. Improvement was seen at 6 months, but results continued to improve at the 1-year mark. By the second year, improvement largely reached a plateau. Biodex testing showed no loss of plantarflexion strength after reconstruction and gastrocnemius recession. CONCLUSION: Reconstruction of the flexible adult acquired flatfoot with FDL transfer, double calcaneal osteotomy, and gastrocnemius recession yielded excellent functional results for the treatment of Stage II posterior tibial tendon insufficiency. Plantarflexion weakness was not found to be a concern. A good functional outcome can be anticipated after the early postoperative period. However, it should be expected to take at least 1 year for maximal benefit.

Adolescent accessory navicular.

Accessory tarsal navicular is a common anomaly in the human foot. It should be in the differential of medial foot pain. A proper history and physical, along with imaging modalities, can lead to the diagnosis. Often, classification of the ossicle and amount of morbidity guide treatment. Nonsurgical measures can provide relief. A variety of surgical procedures have been used with good results. Our preferred method is excision for small ossicles and segmental fusion after removal of the synchondrosis for large ossicles. In addition, pes planovalgus deformities need to be addressed concomitantly.

Commonly missed peritalar injuries.

Because of the effect on hindfoot kinematics, missed or delayed diagnosis of peritalar injuries often results in impairment. The seemingly innocuous nature of these injuries, subtle radiographic findings, and low incidence limit familiarity, thereby increasing the likelihood of misdiagnosis. Because of delay in diagnosis, salvage arthrodesis may be necessary to restore function to the extremity. Talar head fracture, talar process fracture, subtalar fracture-dislocation, transverse tarsal joint fracture, and transverse tarsal ligamentous disruption with instability are recurrently misdiagnosed. The keys to proper diagnosis of these potentially devastating injuries are the recognition of their existence, their injury patterns, and their radiographic appearance. The threshold for additional imaging studies should be lowered when a patient has pain and physical examination findings are out of proportion to a provisional diagnosis, or when symptoms fail to improve.

Analysis of retrieved agility total ankle arthroplasty systems.

BACKGROUND: First generation total ankle arthroplasty (TAA) systems showed high rates of failure. The Agility (DePuy, Warsaw, IN) TAA system, a second generation design, had improved outcomes; however, implant failure due to loosening of the metallic components persisted. The purpose of this study was to analyze the damage modes and radiographic mode(s) of failure observed in retrieved Agility TAA. MATERIALS AND METHODS: Ten devices were collected and each component was analyzed for common damage modes using microscopy. Clinical damage was analyzed with postoperative implant and preoperative revision procedure radiographs. RESULTS: Analyses revealed damage/wear to retrieved components, including abrasion, dishing, and pitting. These third-body wear particles may be a precursor to wear debris induced osteolysis which could cause component loosening. Seven TAA systems were removed due to loosening or subsidence, suggesting component damage/wear may lead to clinically observed component loosening. Retrieval analysis indicated the polyethylene experiences edge loading, resulting in increased contact stresses to polyethylene in the primary articulation region and wear. CONCLUSION: Since poor clinical outcomes have been associated with component instability and osteolysis, analyzing retrieved components wear and damage may be an important step toward improving implant design, thereby decreasing wear debris induced osteolysis and improving clinical outcomes.

Effects of hindfoot constraint on syndesmotic displacement.

BACKGROUND: The effects of altered hindfoot kinematics on the syndesmosis have not been previously studied. Our purpose was to test how the magnitude of displacement across the syndesmosis changes under simulated subtalar (ST) and/or talonavicular (TN) fusion and with altered hindfoot position in a cadaveric model. MATERIALS AND METHODS: Six cadaveric specimens (three matched pairs) age 33 to 43 years were disarticulated at the knee and mounted into a custom six-degree-of-freedom testing frame with a simulated ground reaction force of 700 N and a tensile Achilles load of 500 N. Specimens were then tested through four cycles of internal and external rotation under four conditions: simulated combined ST + TN fusion, ST fusion alone, TN fusion alone and no fusion. Each condition was tested in the neutral coronal position and 9 degrees of inversion and eversion. Infrared light emitting diode (irLED) marker arrays were used to track displacement across the anterior tibiofibular ligament (ATiFL) in order to assess displacement across the syndesmosis. RESULTS: Without fusion, displacement across the ATiFL in inversion is greater than that in neutral (p = 0.015). With ST, the measured ATiFL displacement in inversion is greater than that in neutral (p = 0.042). In neutral, the combined ST + TN significantly increased ATiFL displacement when compared to no fusion (p = 0.0043). Increased displacement was seen in inversion compared to eversion in all testing conditions. CONCLUSION: Simulated ST and TN fusion increases displacement across the ATiFL during simulated physiologic loading. Hindfoot inversion also increases displacement of the ATiFL. CLINICAL RELEVANCE: These observations may have clinical implications with respect to syndesmotic injury and total ankle arthroplasty.

Classification and treatment of severe ankle articular segment deficits: osteochondral allograft reconstruction.

Severe ankle degeneration can be a devastating problem for young adults. Although ankle fusion continues to be the gold standard, inherent long-term problems are related to this treatment option. Further advances in total ankle prosthetic arthroplasty are needed before this treatment option can be considered suitable in a younger population. The use of fresh osteochondral allograft transplantation can provide an alternative treatment option without precluding future salvage procedures. Future studies may further define the role immunosuppression can play in improving fresh osteochondral allograft viability.

Idiopathic cavovarus and lateral ankle instability: recognition and treatment implications relating to ankle arthritis.

Hindfoot malalignment and chronic lateral ankle instability may lead to degenerative ankle arthritis. We retrospectively analyzed 10 patients with 13 cavovarus feet. None of the patients had underlying neurologic disorders. All patients presented with a history consistent with chronic lateral ankle instability, clinically with cavovarus feet, and radiographically with varying degrees of varus talar tilt and ankle arthritis. Ankles with severe degenerative change were fused. The ankles with mild or moderate change underwent calcaneal osteotomy with lateral ligament reconstruction and/or dorsiflexion osteotomy of the first metatarsal. A quantitative radiographic Coleman block test was utilized to aid in the preoperative planning of the calcaneal and metatarsal osteotomies. All patients had correction of preoperative deformity and resolution of pain and instability. Recognition of the association between cavovarus and chronic ankle instability and degenerative ankle arthritis may be important in developing the appropriate treatment strategy in this patient population.