Lower Bone Density on Preoperative Computed Tomography Predicts Periprosthetic Fracture Risk in Total Ankle Arthroplasty

SPECT/CT of Total Ankle Arthroplasty

Use of SPECT/CT (Single Photon Emission Computed Tomography/Computed Tomography) is increasing providing additional information in patients with inconclusive clinical examination and unremarkable imaging findings presenting with chronic pain after total ankle arthroplasty. To differentiate the cause of pain after total ankle arthroplasty can be challenging. SPECT/CT combines structural and metabolic imaging as a hybrid tool leading to higher specificity and overall diagnostic accuracy presumably in cases of gutter impingement, prosthetic loosening, and osteoarthritis of adjacent joints. Moreover, SPECT/CT can complement diagnostic work up in periprosthetic joint infections. Basal tracer enhancement has to be considered for the interpretation of imaging findings.

Postoperative Medial Malleolar Fractures in Total Ankle Replacement Are Associated With Decreased Medial Malleolar Width and Varus Malalignment: A Case-Control Study

BACKGROUND

There are limited data regarding risk factors associated with periprosthetic medial malleolar fractures in total ankle arthroplasty (TAA). This case-control study aimed to identify the risk factors and analyze the effect of prophylactic screw fixation in preventing a medial malleolar fracture after TAA.

METHODS

A case-control study was conducted on 149 patients who underwent primary TAA. Twenty patients with postoperative medial malleolar fractures >4 weeks postoperatively (cases) were identified. An additional 129 patients (controls) were randomly selected from the TAA database. Radiographic evaluation included tibial component coronal alignment and postoperative medial malleolar width. Demographics and radiographic variables were compared between cohorts. Logistic regression was used to investigate the association between medial malleolar fracture and postoperative coronal alignment, medial malleolar width, and prophylactic fixation of the medial malleolus.

RESULTS

Mean (SD) medial malleolar width was significantly smaller in the fracture cohort (8.52 mm [1.6]) than in the control group (11.78 mm [1.74]) (P < .001). Mean (SD) tibial component coronal alignment was 92.17 degrees (2.77) in the fracture cohort and 90.21 degrees (1.66) in the control group (P = .002). Regression analysis identified a significant negative association between postoperative medial malleolar width and the probability of fracture (OR = 0.06, 95% CI 0.01, 0.26, P < .001). Varus malalignment of the tibial component was positively associated with the probability of fracture (OR = 1.90, 95% CI 1.27, 2.86, P = .002). Prophylactic screw fixation resulted in more than 90% reduction in the odds of a fracture (OR = 0.04, 95% CI 0.01, 0.45, P = .01). ROC curve analysis determined a medial malleolar width of 10.3 mm as a potential threshold for predicting fracture.

CONCLUSION

Decreased medial malleolar width and postoperative varus malalignment were associated with an increased risk of postoperative medial malleolar fracture. Therefore, surgeons should consider prophylactic screw fixation in patients with a medial malleolar width <10.3 mm or at risk of postoperative varus deformity.

Is smoking a risk factor for complications following total ankle arthroplasty? A meta-analysis

BACKGROUND

Smoking has long been recognized as a risk factor for impaired wound and bone healing, particularly in the context of ankle and foot surgery. Despite numerous studies exploring the association between smoking and complications following ankle replacement, there remains significant inconsistency in their findings. Therefore, this meta-analysis study aims to elucidate whether smoking increases the rate of complications after total ankle arthroplasty (TAA), providing valuable insights for clinical management.

METHODS

A comprehensive systematic search was conducted in the PubMed, Embase, and Wiley databases to identify relevant English studies on the influence of smoking on postoperative complications following ankle replacement without any restrictions on publication dates. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. Random-effect models were used to calculate odds ratios (OR) and 95 % confidence intervals (CI). This study adhered to PRISMA guidelines for transparent reporting and was registered with PROSPERO.

RESULTS

The analysis incorporated data from 12 retrospective cohort studies, totaling 17331 subjects, 2580 of whom were smokers and 791 complications following TAA. The findings revealed a statistically significant disparity in wound-related complications (OR: 2.26; 95 % CI: 1.13-4.50; P = .02), particularly evident in current smokers with an OR of 3.30 (95 % CI: 2.12-5.14; P < .00001). However, we lacked sufficient evidence to substantiate an association between smoking and complications related to the prosthesis (OR: 1.09; 95 % CI: 0.77-1.53; P = .64) or systemic complications (OR: 1.18; 95 % CI: 0.10-14.13; P = .90) following TAA.

CONCLUSIONS

Smoking, especially current smoking, is associated with increased wound complication risk post-operation for total ankle arthroplasty. Despite a lack of definitive evidence on the optimal timeframe for smoking cessation before surgery, discontinuing smoking appears to be a prudent measure to mitigate these complications.

Outcomes following total ankle total talus replacement: A systematic review

BACKGROUND

Prosthetic substitution of the talus presents a significant challenge to the foot and ankle surgeon. The shear and compressive forces on the talus and its tenuous blood supply lead to high rates of avascular necrosis and eventual talar collapse. The purpose of this systematic review is to evaluate whether total ankle total talus replacement (TATTR) leads to improved clinical and radiographic outcomes with appropriate safety metrics in patients with a history of avascular necrosis or significant trauma.

METHODS

We searched the concepts of talus, prosthesis, and arthroplasty in MEDLINE (PubMed), Embase (Elsevier), CINAHL Complete (EBSCOhost), and Scopus (Elsevier) from the database's inception through March 9, 2023. Inclusion Criteria were 1) previous trauma to the talus, 2) post-traumatic arthritis to the tibiotalar joint, 3) avascular necrosis of talus, 4) multiple failed prior interventions, 5) degenerative osteoarthritis to the tibiotalar joint, and 6) inflammatory arthropathy to tibiotalar joint. Patients less than 18 years of age and manuscripts in non-English languages were excluded.

RESULTS

Of the 7625 references, 16 studies met the inclusion criteria, yielding data from 136 patients (139 ankles). The studies varied in design, with case reports and retrospective case series being predominant. The overall weighted average modified Coleman Methodology Score (mCMS) was 70.4 out of 100, indicating moderate flaws in study design that may be subject to various forms of bias and possible confounders. Demographics showed a diverse range of etiologies, with alumina ceramic being the primary prosthesis material. Functional scores demonstrated improvements in dorsiflexion and plantarflexion, although patient-reported outcome measures (PROs) were inconsistently reported. Complications included fractures, heterotopic ossification, prolonged wound healing, and infections. Revision details were sparsely reported.

CONCLUSION

TATTR is a promising treatment modality for improving short-term functional outcomes for patients with avascular necrosis or trauma-related issues. However, this systematic review underscores the need for standardized reporting, longer-term follow-ups, and further research to establish the procedure's efficacy and safety, particularly in comparison to other treatment modalities.

LEVEL OF EVIDENCE

III, Systematic Review of Level IV Studies.

Managing Intraoperative Fractures During Total Ankle Replacement

Intraoperative complications during total ankle replacement (TAR) can be devastating. As surgeons' experience with total ankles grow and surgical techniques are refined, intraoperative complications, such as fractures, can still occur. Surgeons must be able to recognize a problem, identify the options to remediate, and then execute a solution readily. Unfortunately, given the heterogeneity of TAR outcome studies, it is difficult to garner the true incidence of complications in the peri-operative period following ankle replacements. The purpose of this review is to focus on perioperative fractures during TAR. Fractures can occur intraoperatively and postoperatively as stress fractures or post-operative trauma.

Obesity and Ankle Prosthesis Revision: A Systematic Review and Meta-analysis

BACKGROUND

The increasing number of total ankle arthroplasties (TAAs) has led to growing evidence on the risk factors for complications after surgery. However, the role of obesity in this patient group has been the subject of much debate. Therefore, this systematic review aimed to investigate the evidence for untoward effects of obesity following TAA.

METHODS

We conducted a comprehensive search on April 28, 2023, in MEDLINE (via PubMed), Embase, and CENTRAL. Eligible observational studies reported on the short- and long-term outcomes of primary TAA, comparing patients with and without obesity (defined as body mass index > 30). Using a random effects model, we calculated pooled odds ratios (ORs) with 95% confidence intervals (CIs) from 2 by 2 tables (event and nonevent in the obese and nonobese primary TAA groups).

RESULTS

Nine studies with 10 388 patients were eligible for inclusion in the meta-analysis. We found significantly higher odds of revision in the obese group compared to the nonobese group (OR = 1.68, CI: 1.44-1.95). However, the odds of overall perioperative complications (OR = 1.55, CI: 0.50-4.80) and wound complications (OR = 1.34, CI: 0.29-6.20) were nonsignificantly higher in the obese group.

CONCLUSION

Based on our results, obesity may have affected long-term outcomes following TAA and may have negatively affected the prosthesis's survival.

Updates on Total Ankle Arthroplasty

The newer generation total ankle arthroplasty constructs afford higher levels of long-term survivability, and for the first in the history of ankle arthroplasty procedures, results are comparable to arthrodesis. Much of the success hinges on appropriate patient selection. A comprehensive workup of the patient will allow selection of adjunctive procedures as well as allowing for the determination of single versus 2-stage deformity correction. With the continual addition of implants, it is important to understand the specialization and indications that are assigned to certain models because this will help in selecting the most appropriate implant for any given patient.

SPECT/CT of Total Ankle Arthroplasty

Use of SPECT/CT (Single Photon Emission Computed Tomography/Computed Tomography) is increasing providing additional information in patients with inconclusive clinical examination and unremarkable imaging findings presenting with chronic pain after total ankle arthroplasty. To differentiate the cause of pain after total ankle arthroplasty can be challenging. SPECT/CT combines structural and metabolic imaging as a hybrid tool leading to higher specificity and overall diagnostic accuracy presumably in cases of gutter impingement, prosthetic loosening, and osteoarthritis of adjacent joints. Moreover, SPECT/CT can complement diagnostic work up in periprosthetic joint infections. Basal tracer enhancement has to be considered for the interpretation of imaging findings.

Identifying the Potential Role of Regional Bone Mineral Density on the Degree of Malleolar Involvement in Acute Ankle Fractures

Ankle fractures are a common traumatic lower extremity injury and are generally classified and characterized by the rotational mechanism of injury. At each malleolus (i.e., posterior, medial, and lateral) a fracture can occur or a ligamentous injury may be sustained. The purpose of this retrospective study was to determine if bone mineral density is a contributing factor on the number of fractured malleoli versus soft tissue injury in adult ankle fractures. Data was obtained from a registry of ankle fractures that were operatively treated by the foot and ankle team throughout our institutional facilities, from July 2017 to August 2019, and in which a preoperative computerized tomography scan was performed. Regional bone mineral density (BMD) was measured by calculating the average Hounsfield Unit (HU) on axial computerized tomography images of the distal fibula and tibia. The average HU was then compared to the number of fractured malleoli. One hundred eight patients met the study criteria. We identified statistically significant relationships between decreased BMD with increasing age (p < .01) and the male gender (p < .01). After adjusting for the covariates age and gender, no statistically significant relationship was identified between BMD and the number of malleoli involved in a given ankle fracture (p = .11). These findings suggest that while more investigation is required for ankle fracture patterns and BMD evaluation, increased age and biologic female gender is significantly related to decreased BMD as identified via HU.

Radiodensity Analysis of Lateral Column Superconstruct Fixation Sites in Midfoot Charcot Neuroarthropathy

Lateral column deterioration and subsequent loss of function poses a challenge for limb preservation in patients with Charcot neuroarthropathy (CN). Application of "superconstructs" provides stability and clinical improvement to an often-ulcerated lateral foot. This study examines radiodensity in Hounsfield units (HU) to compare bone quality of lateral column fixation targets using computed tomography (CT) scans between patients with and without midfoot CN. A retrospective chart review identified control (nondiabetic, non-CN; n = 29) and midfoot CN (n = 21) groups. Patient demographics and medical history were collected. Two reviewers measured the mean HU of circular regions of interest centered on the fourth and fifth metatarsal heads as well as the anterior, middle, and posterior thirds of the calcaneus. Radiodensity was compared between groups, among calcaneal locations, Eichenholtz stages and Brodsky types. A p value ≤.05 was considered statistically significant. Age and body mass index were not significantly different between groups. The CN group exhibited greater HU than the control group at the metatarsal head and calcaneus (p < .001). The anterior calcaneus exhibited greater HU than the posterior calcaneus in the CN group (p = .02). The difference in HU was not statistically significant between Stages 0-1 and Stages 2-3 or midfoot Brodsky Types. Indirect bone density analysis revealed an increased density in CN compared to control patients with no significant difference between midfoot CN stages or types. The anterior calcaneus was the densest rearfoot bone among the CN patients, a result that may have implications in surgical fixation.

Fast-Track for Total Ankle Replacement: A Novel Enhanced Recovery Protocol for Select Patients

BACKGROUND

Enhanced recovery after surgery programs, also called fast-track protocols, were developed and successfully applied in the last decade for hip and knee reconstruction. Specific fast-track protocols have not yet been applied to ankle prostheses. The aim of the study was to develop and validate an enhanced recovery protocol for total ankle replacement (TAR) evaluating the clinical and radiographic results. We hypothesize that on the basis of well-defined pre- and postoperative characteristics, the current knowledge on ankle replacement, and referring to hip and knee reconstruction, it is possible to identify a "patient type" to be safely eligible to a Fast-Track Protocol with at least comparable results and without increasing the complications risk.

METHODS

We identified 8 predictive variables that might affect the outcome of TAR. Those variables were the body mass index, the state of anxiety or depression, the functional preoperative status, ankle equinus, the coronal malalignment, the surgical time, the surgical accessory procedures, and the bone quality. These characteristics were evaluated for each patient with almost validated outcome tools attributing a specific score. Based on the score obtained, the patients were divided into 2 groups: the Standard Protocol group (Control Group) and the Fast-Track Protocol group (Study Group). The main difference between treatment of the 2 groups relates to the use of postoperative plaster casts: in the Fast-Track group the cast was removed the first day after surgery and walking was allowed in sports shoes assisted with crutches, whereas in the Standard Protocol group, the cast was removed after 3 weeks. Clinical and radiographic evaluation was performed for all patients preoperatively and postoperatively every 6 months.

RESULTS

A total of 163 patients received a score between 1 and 5 and were included in the control group (Standard Protocol); 47 patients received a score of 0 and were allocated to the study group (Fast-Track Protocol). Clinically, except for the preoperative American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale score, no statistically significant differences were recorded in the multiple comparisons between the 2 groups. No significant differences were found regarding complications.

CONCLUSION

In selected patients, it is possible to apply an enhanced recovery protocol of rehabilitation, focused on immediate weightbearing and mobilization without any plaster or boot.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Assessment of Bone Mineral Density in the Distal Tibia Using Quantitative Hounsfield Samples From Computer Tomography

The distal tibia bone quality is of paramount importance for ankle fractures, total ankle implants, ankle fusions, and osteotomy procedures. Despite this fact relatively little is known regarding the overall bone quality for this section of the tibia. Previous literature suggest that there is a statistically significant decrease in bone mineral density within the distal 5% to 10% segment of the tibia medullary canal. This segment of medullary bone is considerable in size and thus valuable for fixation constructs as it is oftentimes utilized for medial malleolar fractures, distal tibia fractures, total ankle replacements, ankle fusions, and other procedures. This study assessed bone attenuation between the distal 5% and 10% mark of the tibia in 1% slices via Hounsfield unit measurements on CT scans based on previously established correlation between Hounsfield units and bone mineral density found on DEXA scans. One hundred five distal tibia segments were assessed with an average interval in percentile slices of 3.8 mm. As expected there was a gradual decrease in bone attenuation noted with each proximal percentile segment. There exists a statistically significant difference in bone attenuation among males versus females as well as those older than 60 years versus younger than 60 years. The findings suggest fixation constructs in the tibia medullary canal may find limited benefit proximal from 7% segment in females ≥60, or 26.1 mm from tibial plafond. Fixation constructs in tibia medullary canal may find limited benefit proximal from 8% segment in males <60, or 32.3 mm from tibial plafond.

Bone Density by Specific Anatomic Location Using Hounsfield Samples of the Lower Extremity: A Multi-center Retrospective Analysis

Understanding bone mineral density and its effects on patient outcomes is a useful tool for lower extremity surgeons. Historically, dual-energy X-ray absorptiometry scans have been the gold standard for quantifying bone mineral density. In this study, we look at an indirect way to measure bone mineral density using Hounsfield units on computed tomography. The aim of this study is to establish normal physiological Hounsfield ranges in specific bones of the foot by analyzing Hounsfield unit measurements and determining associated factors. We hypothesize that there will be a difference in density based on age, sex, and anatomic location. Patient data from January 2010 to January 2020 were retrospectively analyzed from 2 institutions. Nine anatomic locations (calcaneus, talar body, talar head, navicular, cuboid, medial cuneiform, head of first and fifth metatarsal, and base of first proximal phalanx) were measured for bone mineral density averages. In total, 137 patients were evaluated (71 males, 66 females) with an average age of 54 years. Significant differences in density were found between the 9 anatomic locations. Age was confirmed to be a significant covariate with inverse relation to Hounsfield units, p < .001. There were no density differences between sexes at any of the locations, except the talar head, p < .001. This is the first study to our knowledge to establish normal physiological ranges of bone density on computed tomography for specific anatomic locations of the foot. This quantitative approach to bone density and the established effect of age, sex, and location is pivotal for diagnostic and preoperative planning.

Radiodensity Analysis of Medial Column Superconstruct Fixation Sites in Midfoot Charcot Neuroarthropathy

Charcot neuroarthropathy (CN) is a highly destructive, pathologic process with devastating consequences to foot structure and viability. The use of intramedullary fixation "superconstructs" allows for "re-bar" support of compromised bone and allows for some dynamic fixation. This study examines radiodensity in Hounsfield units (HU) to compare bone quality of medial column fixation targets using computed tomography scans between patients with and without midfoot CN. A retrospective chart review identified control (nondiabetic, non-CN; n = 29) and midfoot CN (n = 21) groups. Patient demographics and medical history were collected. Two reviewers measured the mean HU of a circular region of interest centered on the first metatarsal head and the anterior, middle, and posterior thirds of the talar body. Radiodensity was compared between groups, and among talar locations, Eichenholtz stages and Brodsky types, with statistical significance set at p ≤ .05. Age and body mass index were not significantly different between groups. The CN group maintained greater mean HU than the control group at the metatarsal head (p < .001), and talar body locations (p < .019). The difference in mean HU of these bones was not statistically significant between Stages 0 to 1 and Stages 2 to 3 or Brodsky Types 1 and 2. Mean HU differences among talus positions were not statistically significant. Indirect bone density analysis using HU showed an increased density in CN patients with no significant difference among talar body locations or midfoot Charcot stages and types. These results may assist in optimizing fixation length. Future studies may examine these densities in ankle CN.

Effects of Patient-Specific Instrumentation and Ancillary Surgery Performed in Conjunction With Total Ankle Implant Arthroplasty: Postoperative Radiographic Findings

Accuracy and reproducibility when performing total ankle implant arthroplasty (TAA) are essential for longevity of the implant, maintaining relative stability of the joint, and theoretically reducing the formation of adjacent joint arthritis in the subtalar and knee joints. Studies have helped to illustrate the accuracy of implantation when using patient-specific instrumentation in both knee and ankle implant arthroplasty. Despite the findings of these studies, few have gone on to evaluate the effects of ancillary procedures on TAA; particularly their effects on postoperative implant congruity when performed simultaneously with joint replacement surgery. In this study, preoperative plans on implant alignment based on patient-specific computed tomography images were compared with the alignment observed on immediate postoperative radiographs. Additionally, postoperative joint congruity was measured, and operative reports were assessed to determine if concomitant procedures performed with total ankle replacement had a significant effect on overall alignment. In our population, 46/47 implants were within 1.5° of their anticipated placement in the coronal plane, and 100% were within 2° of anticipated placement in the sagittal plane. Using a spearman's rank-order correlation, our data failed to show any significant relationship between conducting additional procedures in conjunction with TAA (rho = 0.178; p value = .232) and postoperative congruency of the implant. These findings help support the accuracy of ankle implantation using patient-specific instrumentation, while also supporting the appropriate use of indicated procedures in conjunction with total ankle replacement to help obtain a congruent joint postoperatively.

Predicting Nonunions in Ankle Fractures Using Quantitative Tibial Hounsfield Samples From Preoperative Computed Tomography: A Multicenter Matched Case Control Study

The aim of this study is to use tibial Hounsfield unit measurements from preoperative computed tomography scans of ankle fractures to predict delayed union and nonunion. We hypothesize that patients with lower Hounsfield unit averages, an indirect measure of lower bone mineral density, in the distal tibia are more likely to develop delayed union and nonunion complications after ankle fracture surgery. Patient data from January 2010 to January 2020 were retrospectively analyzed from 2 institutions. Exposure cases of delayed union or nonunion that had preoperative computed tomography were compared to 5 controls matched for sex, age, and classification. 3 measurements were taken from the tibia on axial computed tomography and averaged to create a summative measure for overall bone health. Statistical analysis was used to analyze the relationship between the groups. 19 exposure patients were compared to 95 control patients. There were 16 females and 3 males in the exposure group aged from 30 to 88 years. Average follow-up was 1.6 years. The average exposure and control Hounsfield measurements were 186 (161-210) and 258 (248-269), respectively. Significant differences were found for all measured averages. This is the first study to our knowledge relating preoperative tibial Hounsfield measurements to healing rates of ankle fractures. Measurements taken from any of the 3 sites or the average could be an indicator of overall bone health. Using this technique on preoperative imaging will help surgeons adjust their perioperative planning for patients at higher risk for delayed union and nonunion.

Outcomes and Complications of the INFINITY Total Ankle: A Systematic Review

IV.

Investigation on the contour and bone mineral density of the distal tibial cutting surface used for total ankle arthroplasty

PURPOSE

This study was designed to investigate (1) the contour of the distal tibial cutting surface, and (2) the bone mineral density (BMD) of the distal tibial cutting surface used during total ankle arthroplasty (TAA).

METHODS

Eight-four distal tibial models were created using foot and ankle computerized tomographic (CT) images taken from normal people. The distal tibial cutting surface for TAA was determined to be 10 mm proximal to the tibial plafond. The bony contour and BMD values were determined from the CT image at that level. A bounding box was made on the contour and the width and length of the contour was measured. Regional BMD was evaluated by Hounsfield units (HU) value measurement, with 7 regions of interest (ROI) on 8 different directions for all the 84 CT images. Two different observers made independent measurements and mean HU values for all the 56 ROIs were calculated.

RESULTS

Great variations were found among the contours of the cutting surface especially in term of the shape of the anterior and posterior tibial tubercle, and the fibular notch. These variations could be grouped into six categories. For the BMD of the cutting surface, the medial border of the cutting surface did not included cortical bone. The HU value of seven ROIs, which included cortical bone, were significantly greater than all the other ROIs. Few statistical differences were found by multiple comparisons among HU value of all the 49 ROIs without cortex.

CONCLUSIONS

Great variability existed in the shape and the BMD of the distal tibial cutting surface.

Evaluating and Managing the Painful Total Ankle Replacement

The number of total ankle replacements (TARs) performed in the United States has dramatically increased in the past 2 decades due to improvements in implant design and surgical technique. Yet as the prevalence of TAR increases, so does the likelihood of encountering complications and the need for further surgery. Patients with new-onset or persistent pain after TAR should be approached systematically to identify the cause: infection, fracture, loosening/subsidence, cysts/osteolysis, impingement, and nerve injury. The alignment of the foot and ankle must also be reassessed, as malalignment or adjacent joint pathology can contribute to pain and failure of the implant. Novel advanced imaging techniques, including single-photon emission computed tomography and metal-subtraction magnetic resonance imaging, are useful and accurate in identifying pathology. After the foot and ankle have been evaluated, surgeons can also consider contributing factors such as pathology outside the foot/ankle (eg, in the knee or the spine). Treatment of the painful TAR is dependent on etiology and may include debridement, bone grafting, open reduction and internal fixation, realignment of the foot, revision of the implants, arthrodesis, nerve repair/reconstruction/transplantation surgery, or, in rare cases, below-knee amputation.Level of Evidence: Level V, expert opinion or review.

Bone Mineral Density Testing in Patients Undergoing Total Ankle Arthroplasty: Should We Pay More Attention to the Bone Quality?

Total ankle arthroplasty (TAA) has become one of the standard treatments for end-stage ankle arthritis. Long-term TAA survivorship is reported from 63% to 95%, with aseptic loosening being the most common mode of failure. Several studies have shown that low bone mineral density (BMD) of the hip affects the longevity of prosthetic implants. The role of Dual energy X-ray absorptiometry for TAA has not been established. The purpose of this review was to define the role of BMD in TAA outcomes and the role of Dual energy X-ray absorptiometry in measuring periprosthetic BMD. There is a paucity of information and published literature regarding the relationship between BMD and TAA. From attempting this systematic review, we hope to highlight that much of the focus in total ankle arthroplasty has emphasized implants and relatively little has focused on the quality of bone into which the prostheses are implanted.

Glenoid bony morphology of osteoarthritis prior to shoulder arthroplasty: what the surgeon wants to know and why

Shoulder arthroplasty is performed with increasing frequency, and osteoarthritis is the most common indication for this procedure. However, the glenoid side of the joint is widely recognized as a limiting factor in the long-term durability of shoulder replacement, and osteoarthritis leads to characteristic bony changes at the glenoid which can exacerbate this challenge by reducing the already limited glenoid bone stock, by altering biomechanics, and by interfering with operative exposure. This article reviews the Walch classification system for glenoid morphology. Several typical findings of osteoarthritis at the glenoid are discussed including central bone loss, posterior bone loss, retroversion, biconcavity, inclination, osteophyte formation, subchondral bone quality, and bone density. The three primary types of shoulder arthroplasty are reviewed, along with several techniques for addressing glenoid deformity, including eccentric reaming, bone grafting, and the use of augmented glenoid components. Ultimately, a primary objective at shoulder arthroplasty is to correct glenoid deformity while preserving bone stock, which depends critically on characterizing the glenoid at pre-operative imaging. Understanding the surgical techniques and the implications of glenoid morphology on surgical decision-making enables the radiologist to provide the morphologic information needed by the surgeon.

Comparison of Preoperative Bone Density in Patients With and Without Periprosthetic Osteolysis Following Total Ankle Arthroplasty

BACKGROUND

Modern total ankle arthroplasty (TAA) prostheses are uncemented press-fit designs whose stability is dependent on bone ingrowth. Preoperative insufficient bone density reduces initial local stability at the bone-implant interface, and we hypothesized that this may play a role in periprosthetic osteolysis. We aimed to investigate the preoperative bone density of the distal tibia and talus and compare these in patients with and without osteolysis.

METHODS

We enrolled 209 patients (218 ankles) who underwent primary TAA using the HINTEGRA prosthesis. The overall mean follow-up duration was 66 (range, 24-161) months. The patients were allocated into 2 groups according to the presence of periprosthetic osteolysis: the osteolysis group (64 patients, 65 ankles) and nonosteolysis group (145 patients, 153 ankles). Between the 2 groups, we investigated and compared the radiographic outcomes, including the Hounsfield unit (HU) value around the ankle joint and the coronal plane alignment.

RESULTS

HU values of the tibia and talus measured at 5 mm from the reference points were higher than those at 10 mm in each group. However, comparing the osteolysis and nonosteolysis groups, we found no significant intergroup difference in HU value at every measured level in the tibia and talus (P > .05). Concerning the coronal plane alignment, there were no significant between-group differences in the tibiotalar and talar tilt angles (P > .05).

CONCLUSION

Patients with osteolysis showed similar preoperative bone density of the distal tibia and talus compared with patients without osteolysis. Our results suggest that low bone density around the ankle joint may not be associated with increased development of osteolysis.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Is preoperative glenoid bone mineral density associated with aseptic glenoid implant loosening in anatomic total shoulder arthroplasty?

Background

Aseptic loosening of glenoid implants is the primary revision cause in anatomic total shoulder arthroplasty (aTSA). While supported by biomechanical studies, the impact of glenoid bone quality, more specifically bone mineral density (BMD), on aseptic glenoid loosening remains unclear. We hypothesized that lower preoperative glenoid BMD was associated with aseptic glenoid implant loosening in aTSA.

Methods

We retrospectively included 93 patients (69 females and 24 males; mean age, 69.2 years) who underwent preoperative non-arthrographic shoulder computed tomography (CT) scans and aTSA between 2002 and 2014. Preoperative glenoid BMD (CT numbers in Hounsfield unit) was measured in 3D using a reliable semi-automated quantitative method, in the following six contiguous volumes of interest (VOI): cortical, subchondral cortical plate (SC), subchondral trabecular, and three successive adjacent layers of trabecular bone. Univariate Cox regression was used to estimate the impact of preoperative glenoid BMD on aseptic glenoid implant loosening. We further compared 26 aseptic glenoid loosening patients with 56 matched control patients.

Results

Glenoid implant survival rates were 89% (95% confidence interval CI, 81–96%) and 57% (41–74%) at 5 and 10 years, respectively. Hazard ratios for the different glenoid VOIs ranged between 0.998 and 1.004 (95% CI [0.996, 1.007], p≥0.121). Only the SC VOI showed significantly lower CTn in the loosening group (622±104 HU) compared with the control group (658±88 HU) (p=0.048), though with a medium effect size (d=0.42). There were no significant differences in preoperative glenoid BMD in any other VOI between patients from the loosening and control groups.

Conclusions

Although the preoperative glenoid BMD was statistically significantly lower in the SC region of patients with aseptic glenoid implant loosening compared with controls, this single-VOI difference was only moderate. We are thus unable to prove that lower preoperative glenoid BMD is clearly associated with aseptic glenoid implant loosening in aTSA. However, due to its proven biomechanical role in glenoid implant survival, we recommend extending this study to larger CT datasets to further assess and better understand the impact of preoperative glenoid BMD on glenoid implant loosening/survival and aTSA outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03892-0.

Infinity ankle arthroplasty with traditional instrumentation and PSI prophecy system: preliminary results

Ankle arthrodesis has been considered the surgical Gold Standard for advanced ankle arthritis; prosthetic replacement of the tibio-talar joint played a secondary role.The introduction of last generation ankle prostheses lead to better outcome and a lower rate of complication. PSI represents the most recent innovations introduced on the market of ankle arthroplasty:PSI is proposed as a surgical technique capable of making ankle arthroplasty more accurate and more reproducible compared to standard referencing guides Aim of the study is to report early clinical and radiographic outcomes obtained from a single surgeon experience by implanting the same ankle prosthesis using a standard (STD) or a PSI instrumentation Unlike no difference in the average increment of normalized sub score related to function in each group (PSI vs STD), the analysis of normalized pain sub score pointed out a greater average improvement in the PSI group(+75%)compared to the STD group(+62%);this result has been adovacated to the absence of post operative gutter impingement syndrome in the PSI group compared to the STD referencing group. The analysis of radiographic angles revealed a more accurate and reproducible positioning of the components in the PSI group; ankle arthroplasty performed with PSI reported a reduction of both surgical times and the need of intraop.fluoroscopy. PSI ankle arthroplasty achived more accurate and reproducible clinical and radiographic results compared to STD instrumentation;long-term follow-up are needed to demonstrate whether a better positioning of the implant is associated with an increased survival of the prosthesis and therefore justifies the additional costs of PSI.

The Optimal Combination of Monochromatic and Metal Artifact Reconstruction Dual-energy CT to Evaluate Total Knee Replacement Arthroplasty

PURPOSE

To evaluate the effects of gemstone spectral imaging-metal artifact reduction (GSI-MAR) on different dual-energy CT monochromatic images for patients with total knee replacement arthroplasty (TKRA) and to identify an appropriate protocol for clinical practice.

METHOD

We enrolled 34 patients with TKRA. CT images were iteratively reconstructed with or without GSI-MAR at different energy levels (70, 95, 115, and 140 keV). Two radiologists evaluated the objective and subjective image qualities and MAR-related new artifacts at the femoral and tibial levels. For objective analysis, the mean CT number and image noise of the selected regions of interest in the bone and muscle were recorded. To quantitatively evaluate the performance of GSI-MAR, a structural similarity index (SSIM) was used. For subjective analysis, streak artifacts and diagnostic confidence in detecting periprosthetic complications were assessed. Objective and subjective indicators were compared among the image combinations.

RESULTS

In the femoral component, 140 keV monochromatic energy images with GSI-MAR showed the lowest mean CT number, image noise, SSIM value, and streak artifacts, and the best diagnostic confidence. In the tibial component, the image noise differed significantly, but the SSIM and subjective indicators were similar among the image combinations. MAR-related new artifacts were noted in 14.7% of images, and all of them were observed in only the femoral component.

CONCLUSION

GSI-MAR with higher-energy monochromatic images showed fewer metal artifacts and better visualization. We recommend 140 keV with GSI-MAR for improving image quality and 140 keV without GSI-MAR for identifying MAR-related new artifacts when evaluating TKRA.

Does gender influence the outcomes of total ankle arthroplasty in patients with ankle osteoarthritis?

Background

Total ankle arthroplasty has progressed as a treatment option for patients with ankle osteoarthritis. However, no studies have been conducted to evaluate the effect of gender on the outcome. The purpose of the present study was to evaluate outcomes, survivorship, and complications rates of total ankle arthroplasty, according to gender differences.

Methods

This study included 187 patients (195 ankles) that underwent mobile-bearing HINTEGRA prosthesis at a mean follow-up of 7.5 years (range, 4 to 14). The two groups consisted of a men’s group (106 patients, 109 ankles) and a women’s group (81 patients, 86 ankles). Average age was 64.4 years (range, 45 to 83).

Results

Clinical scores on the Ankle Osteoarthritis Scale for pain and disability, and American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved and the difference was not statistically significant between the two groups at the final follow-up. There were no significant differences in complication rates and implant survivorship between the two groups. The overall survival rate was 96.4% in men and 93.4% in women at a mean follow-up of 7.5 years (p = 0.621).

Conclusions

Clinical outcomes, complication rates, and survivorship of total ankle arthroplasty were comparable between men and women. These results suggest that gender did not seem to affect outcomes of total ankle arthroplasty in patients with ankle osteoarthritis.

Level of evidence

Therapeutic level III

Effect of bone density and cement morphology on biomechanical stability of tibial unicompartmental knee arthroplasty

BACKGROUND

Unicompartmental knee arthroplasty (UKA) offers good long-term survivorship and superior kinematics and function compared with total knee arthroplasty (TKA). However, revision rates are higher with aseptic loosening representing a major cause. Biomechanical stability depends on cement penetration. The goal of this study was to analyze the influence of cement morphology and bone density on primary stability of tibial UKA under physiological loading conditions in human tibiae.

METHODS

Thirty-six tibial trays were implanted in fresh-frozen human cadaver knees and tested for primary stability using dynamic compression-shear testing. Prior to implantation, bone density had been quantified for all 18 tibiae. Postoperatively, cement penetration has been assessed on frontal cuts based on eight predefined parameters. The influence of bone density and cement morphology on biomechanical stability was determined using correlation and linear regression analysis.

RESULTS

Mean failure load was 2691 ± 832.9 N, mean total cement thickness was 2.04 ± 0.37 mm, mean cement penetration was 1.54 ± 0.33 mm and mean trabecular bone mineral density (BMD) was 107.1 ± 29.3 mg/ml. There was no significant correlation between failure load and cement morphology (P > .05). Failure load was significantly positive correlated with trabecular BMD (r = 0.843; P < .0001) and cortical BMD (r = 0.432; P = .0136).

CONCLUSIONS

Simulating physiological loading conditions, the failure load of tibial UKA is linearly dependent on the trabecular BMD. The observed parameters of cementation morphology seem capable of preventing failure at the bone-cement interface before inherent bone stability is reached. Further research is required to assess the usefulness of a preoperative assessment of bone quality for patient selection in UKA.

Algorithm for Management of Periprosthetic Ankle Fractures

BACKGROUND

Evidence on the management of and outcomes from periprosthetic fractures about a total ankle replacement (TAR) are limited. The purpose of this study was to develop an algorithm for the management of patients with postoperative periprosthetic fractures about a TAR.

METHODS

This was a retrospective analysis of patients undergoing a TAR from 2007 through 2017 with a subsequent periprosthetic fracture >4 weeks from index surgery. Implant stability was defined radiographically and intraoperatively where appropriate. Univariate and multivariate analyses were used to identify differences in outcomes. Thirty-two patients were identified with a remote TAR periprosthetic fracture with an average follow-up of 26 months (range, 3-104 months).

RESULTS

Most fractures were located about the medial malleolus (62.5%); the majority of fractures (75%) were deemed to have stable implants. Fractures of the talus always had unstable implants and always required revision TAR surgery (100%, P = .0002). There was no difference in patient-reported outcomes between stable and unstable fractures at an average of 36 months. In a multivariate analysis, fracture location (talus), less time to fracture, and implant type were found to be predictive of unstable implants ( P < .001). Implant stability was independently associated with the need for revision surgery ( P < .049). Nonoperative treatment was independently associated with treatment failure ( P < .001).

CONCLUSION

The majority of stable fractures about a TAR required operative fixation. Management with immobilization was fraught with a high rate of subsequent surgical intervention. We found that fractures about the talus required revision TAR surgery or arthrodesis.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.