Pathogenesis, Evaluation, and Management of Osteolysis Following 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.

The Role of Receptor Activator of Nuclear Factor-κB Ligand/Osteoprotegerin Ratio in Synovial Fluid as a Potential Marker for Periprosthetic Osteolysis Following Total Ankle Arthroplasty

Background

Periprosthetic osteolysis is a prevalent complication following total ankle arthroplasty (TAA), implicating various cytokines in osteoclastogenesis as pivotal in this process. This study aimed to evaluate the relationship between osteolysis and the concentrations of osteoclastogenesis-related cytokines in synovial fluid and investigate its clinical value following TAA.

Methods

Synovial fluid samples from 23 ankles that underwent revision surgery for osteolysis following TAA were analyzed as the osteolysis group. As a control group, we included synovial fluid samples obtained from 23 ankles during primary TAA for osteoarthritis. The receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) ratio in these samples was quantified using sandwich enzyme-linked immunosorbent assay techniques, and a bead-based multiplex immunoassay facilitated the detection of specific osteoclastogenesis-related cytokines.

Results

RANKL levels averaged 487.9 pg/mL in 14 of 23 patients in the osteolysis group, with no detection in the control group's synovial fluid. Conversely, a significant reduction in OPG levels was observed in the osteolysis group (p = 0.002), resulting in a markedly higher mean RANKL/OPG ratio (0.23) relative to controls (p = 0.020). Moreover, the osteolysis group had increased concentrations of various osteoclastogenesis-related cytokines (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, IL-8, IP-10, and monocyte chemotactic protein-1) in the synovial fluid relative to the control group.

Conclusions

Our results demonstrated that periprosthetic osteolysis was associated with osteoclastogenesis activation through an elevated RANKL/OPG ratio following TAA. We assume that RANKL and other osteoclastogenesis-related cytokines in the synovial fluid have clinical value as a potential marker for the development and progression of osteolysis following TAA.

Early experience with a 3-D printed porous surface, fixed-bearing, total ankle arthroplasty: A minimum of 2-year follow-up

BACKGROUND

This is a pilot study reviewing patients undergoing ankle replacement with the 3-D printed INFINITY™ with ADAPTIS™ total ankle arthroplasty (TAA) system.

METHODS

A retrospective review was conducted of patients with a minimum two-year follow-up who underwent TAA with the INFINITY™ with ADAPTIS™ implant system. Outcome measures include implant survivorship, complications with subsequent reoperations, patient reported outcomes, and radiologic subsidence or radiolucency.

RESULTS

Thirty patients were included with median follow-up of 26 months (range, 24-36). Implant survival rate was 90% (27/30). Two patients experienced linear radiolucency > 2 mm: one required a revision TAA secondary to tibial subsidence; the other patient was asymptomatic and nonprogressive on serial radiographs. No cystic radiolucencies > 5 mm were identified. VAS, PROMIS PF, and FADI scores improved significantly.

CONCLUSION

TAA performed with the 3-D printed INFINITY™ with ADAPTIS™ implant technology led to ninety percent short term implant survivorship and improvement in patient reported outcomes with comparable results to other 4th generation arthroplasty systems as a treatment modality for end-stage ankle arthritis.

LEVEL OF EVIDENCE

Level III, Retrospective cohort study, Prognostic.

Comparing Rates of Radiographic Baseplate Loosening Between Cement and Cementless INFINITY Total Ankle Prostheses

INTRODUCTION

Total ankle replacement is indicated for end-stage ankle osteoarthritis. Periprosthetic radiolucency, from separation between the bone and implant, is suggested to be indicative of potential prosthesis failure risk. Anchoring implants with cement may mitigate this. This study aimed to compare rates of periprosthetic radiolucency between patients with cement-affixed and cementless implants.

METHODS

A retrospective analysis was performed on 28 patients who underwent total ankle replacement with the INFINITY Total Ankle System (Wright Medical, Memphis, Tennessee) implant between January 2016 and May 2022. Anteroposterior, mortise, and lateral ankle X-rays were reviewed by 2 independent reviewers for tibiotalar angle, talar tilt, and periprosthetic radiolucency. The Wilcoxon rank-sum test and chi-square test were performed.

RESULTS

The incidence of periprosthetic radiolucency at the most recent follow-up did not significantly differ between cement and cementless groups (57.1% in both groups, P = 1.0). Follow-up tibiotalar and talar tilt angles were not significantly different (P > .51 for all comparisons).

CONCLUSIONS

Patients with cemented implants had a similar incidence of periprosthetic radiolucency compared with patients with cementless prostheses. Understanding of long-term clinical outcomes will help inform optimal operative approaches for ankle prostheses.

LEVELS OF EVIDENCE

Therapeutic, Level III, Retrospective cohort 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.

Lack of Consensus on the Definition of Aseptic Loosening in Total Ankle Replacement: A Narrative Systematic Review

Background: Aseptic loosening is one of the most common modes of failure of total ankle replacement (TAR). However, a precise definition of aseptic loosening is still lacking. This systematic review aimed to identify the variations of applied definitions and offer insights into the lack of consensus. Methods: Human studies reporting aseptic loosening of TAR published in peer-reviewed journals within the last decade were considered. The search strategy involved specific terms in Embase, MEDLINE ALL, and the Cochrane Library. Variations in aseptic loosening definitions were analysed. Results: Of 767 studies, 88 were included in this study. Only nine studies precisely defined aseptic loosening with significant variations. Twenty-two studies referenced the term and fifty-seven reported it as a complication but neither defined nor referenced it. Conclusions: Significant uncertainty exists regarding the universal definition of aseptic loosening of TAR, and many variations occur in terms of the assessment approach and criteria.

Survival and risk assessment in revision arthroplasty of the ankle

Aims

Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined.

Methods

This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up.

Results

The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up.

Conclusion

Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved.

Talar component subsidence correlates with periprosthetic osteolysis after total ankle arthroplasty

PURPOSE

This study aimed to investigate the relationship between periprosthetic osteolysis around the talar component and the amount of talar component subsidence after total ankle arthroplasty (TAA).

METHODS

This study included forty patients who underwent TAA with a mean follow-up of 67.5 ± 17.0 months. The patients were divided into two groups based on the amount of osteolysis around the talar component, as measured by computed tomography at the latest clinic visit: none to 2 mm (N group, n = 20) and greater than or equal to 2 mm (O group, n = 20). The average amount of talar component subsidence, clinical outcomes, and complications were compared between the two groups. In the O group, the correlation between osteolysis and talar component subsidence was evaluated.

RESULTS

The average talar component subsidence was significantly different between the N (0.22 ± 0.94 mm) and O groups (2.12 ± 2.28 mm). Five out of 20 ankles in the O group required revision surgery owing to talar component subsidence. The Japanese Society for Surgery of the Foot scores in the N and O groups were significantly different: 93.5 ± 7.7 and 85.3 ± 15.4, respectively. In the O group, we found that osteolysis tended to develop on the lateral side, and the amount of osteolysis was positively correlated with the talar component subsidence (r = 0.59, P = .007).

CONCLUSION

In the O group, a positive correlation between osteolysis and talar component subsidence was found, and five patients required revision surgery.

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.

The ceramic coated implant (CCI). Evolution total ankle replacements: a retrospective analysis of 40 ankles with 8 years follow-up

Diminutive data is available on the outcome of several previously used total ankle replacement implants. The purpose of this study was to investigate the medium-term functional and radiological outcome and implant survival of the CCI Evolution implant. Consecutive series of 40 ankles operated in our hospital with primary TAR using the CCI Evolution implant in 2010-2013 were available for follow-up. The prospective clinical and radiographic data including the Kofoed score, subjective satisfaction and standard radiographs were collected preoperatively and at fixed time-points postoperatively. A CT was obtained in cases where osteolysis or loosening were suspected. The improvement of the Kofoed score and subjective satisfaction were statistically significant (p<0.0001). The implant survival was 97% (95% confidence interval (CI) 81%-100 %) at 5 years, and 81 % (95% confidence interval (CI) 60 %-92%) at 8 years. There were altogether 25 (64%) complications. Overall revision rate was 28% and failure rate 13%. The CCI implant outcome was not acceptable. The malposition of prosthetic components, subsidence, and peri-implant osteolysis were recorded often. Although the patient reported outcome measures improved, mostly due to positive changes in pain severity, overall revision and failure rates were high and comparable with previous findings of the CCI implant.

Metal debris release is commonly seen from explanted total ankle replacements

This study aimed to characterise the damage mechanisms present on the metal components used in various contemporary total ankle replacements. Twenty-seven explanted total ankle replacements comprising 8 different designs (3 fixed bearing and 5 mobile bearing) were analysed using various explant analysis techniques. Pitting and scratching were the most commonly observed wear features. Microscopic analysis revealed metallic pitting on 52% of tibial components and 95% of talar components. Pitting was identified on more cobalt-chromium than titanium alloy tibial components (63% versus 0%). Non-contact profilometry confirmed the presence of pitting, with significant (p < 0.05) differences in the measured average surface roughness values of pitted and unpitted areas for tibial and talar components. There was macroscopically visible sliding plane scratching, indicating the presence of hard third body particles, on 78% of talar components. Changes to the non-articulating surfaces coatings in terms of coating loss and/or changes in reflectivity was identified visually on 80% of metal components. Scanning electron microscopy with energy dispersive X-ray spectroscopy identified metallic embedded debris in 19% of polyethylene inserts. This explant study demonstrates the release of metal debris from both the metallic tibial and talar component articulating surfaces and non-articulating surface coatings of various contemporary total ankle replacements. Metal particulate debris release from total ankle replacements may be more common than previously recognised. Metal debris should be considered in further study into the aetiology of failed total ankle arthroplasty.

Use of Femoral Head Allograft for Extended Bone Loss in Revision Total Ankle Arthroplasty: A Case Report

CASE

A 38-year-old male patient presented with severe ankle pain 13 years after a total ankle arthroplasty (TAA). Radiographic evaluation revealed loosening of the implant and extensive osteolytic lesions. The medial tibial plafond and malleolus were reconstructed using a fresh-frozen femoral head graft, and revision TAA was performed. The midterm results were satisfactory, with adequate integration of the allograft and stable implant components.

CONCLUSION

The use of the allograft technique in revision TAA is feasible in the presence of severe bone loss, including the malleoli, and allows firm component fixation of the reconstructed bone.

Management of Periprosthetic Bone Cysts After Total Ankle Arthroplasty

Modern improvements in total ankle arthroplasty (TAA) have increased the performance of this procedure for treatment of end-stage ankle arthritis. A common finding after TAA is the formation of periprosthetic bone cysts, which can be clinically silent or result in TAA failure. The exact cause of periprosthetic bones cysts has not been established, but major theories are related to osteolysis secondary to implant wear, micromotion, and stress shielding. Treatment can be nonoperative with clinical observation for small, asymptomatic cysts. Large, progressive, and symptomatic cysts often merit surgical treatment with debridement and grafting, revision TAA, or salvage arthrodesis.

Early Radiographic and Clinical Outcomes of a Novel, Fixed-Bearing Fourth-Generation Total Ankle Replacement System

BACKGROUND

The Cadence Total Ankle System is a 2-component, fixed-bearing fourth-generation total ankle arthroplasty (TAA) system that was introduced for clinical use in 2016. The purpose of this study was to report non-inventor, non-industry funded survivorship, radiographic and clinical outcomes, and early complications following use of this implant at a minimum of 2 years.

METHODS

This single-center retrospective study included patients who underwent TAA by 2 surgeons with this novel fixed-bearing system between January 2017 and September 2018. Forty-eight patients were evaluated at an average of 33.6 months. Radiographic outcomes included preoperative and postoperative tibiotalar angle on anteroposterior radiographs of the ankle, sagittal tibial angle (STA) on lateral radiographs of the ankle, and periprosthetic lucency formation and location. Revision and reoperation data were collected, and patient-reported outcomes were assessed using Patient Reported Outcomes Measurement Information System (PROMIS). Subgroup analysis assessed associations between preoperative deformity, postoperative implant alignment, PROMIS scores, and periprosthetic lucency formation.

RESULTS

Survivorship of implant was 93.7%, with 3 revisions, 1 due to infection and 2 due to loosening of the implant (1 tibial and 1 talar component). Three patients had reoperations (6.3%): 2 for superficial infection and 1 for gutter debridement due to medial gutter impingement. Fifteen patients (35.8%) developed periprosthetic lucencies, all on the tibial side. PROMIS scores improved after surgery in all domains except Depression. Patients with significant postoperative periprosthetic lucency had worse postoperative PROMIS Physical function scores than patients without lucency (P < .05).

CONCLUSION

This study demonstrated excellent minimum 2-year clinical and radiographic outcomes and low revision and reoperation rates of this new fourth-generation TAA system. Future studies with longer follow-up, especially on patients with periprosthetic lucency, are necessary to investigate the long-term complications and understand the long-term functional and radiographic outcomes of this implant.

Long-Term Clinical Outcomes and Implant Survivorship of 151 Total Ankle Arthroplasties Using the HINTEGRA Prosthesis: A Minimum 10-Year Follow-up

BACKGROUND

Few studies have investigated long-term clinical outcomes of a mobile-bearing total ankle arthroplasty (TAA) system. This study analyzed long-term outcomes of TAA using the HINTEGRA prosthesis at a single, non-developer center.

METHODS

Primary TAAs were performed on 213 ankles in 194 patients, and 151 consecutive ankles [71%] in 136 patients with a minimum follow-up of 10 years after the primary TAA were included in this study. Clinical results were assessed using a visual analog scale (VAS) pain score, the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale score, the Ankle Osteoarthritis Scale (AOS) pain and disability subscores, and ankle range of motion. Prosthesis survivorship, reoperations, and risk factors were also evaluated.

RESULTS

The mean follow-up was 135.5 months (range, 120.0 to 204.0 months). All clinical scores and ankle range of motion improved significantly from preoperatively to 2 years, 4 to 6 years, and ≥10 years after TAA (p < 0.001). A total of 43 ankles (28.5%) required revision procedures, with the most common reason being periprosthetic osteolysis (32 ankles [21.2%]). The overall implant survivorship was 93.5% in Kaplan-Meier survival analysis at the mean follow-up of 11.3 years after the TAA.

CONCLUSIONS

TAA using the HINTEGRA prosthesis with careful follow-up observation and appropriate adjunct procedures for the treatment of end-stage ankle arthritis produced satisfactory clinical results, which were maintained at a follow-up of ≥10 years, and resulted in 93.5% of implant survivorship.

LEVEL OF EVIDENCE

Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Periprosthetic Osteolysis as a Risk Factor for Revision After Total Ankle Arthroplasty: A Single-Center Experience of 250 Consecutive Cases

BACKGROUND

Periprosthetic osteolysis after total ankle arthroplasty (TAA) is a challenging problem. This study aimed to evaluate the prevalence of and predisposing factors for osteolysis and its effects on clinical outcomes.

METHODS

We enrolled 236 patients (250 ankles) who underwent primary TAA using a mobile-bearing HINTEGRA prosthesis, with a mean follow-up of 83.5 months (range, 36 to 182 months), and subsequently divided them into 2 groups: the osteolysis group (79 ankles) and non-osteolysis group (171 ankles). Clinical and radiographic outcomes were compared between the 2 groups, and a bivariable logistic regression analysis was performed to identify predisposing factors for the development of osteolysis.

RESULTS

In the osteolysis group (31.6% of the 250 ankles), the mean time of detection was 28.8 months postoperatively. Forty of these ankles were closely monitored without surgical treatment. Another 29 ankles underwent bone grafting and exchange of the polyethylene inlay, and the remaining 10 ankles underwent revision TAA or arthrodesis. All clinical outcome variables were significantly lower in patients with osteolysis, compared with those without osteolysis, at the final follow-up (p < 0.05). In the investigation of predisposing factors, only rheumatoid arthritis was identified as having a significant association with an increased prevalence of osteolysis (p = 0.030).

CONCLUSIONS

This study demonstrated that the prevalence of periprosthetic osteolysis after TAA was considerable and that the development of osteolysis negatively affected the clinical outcome. Therefore, the prevention and appropriate treatment of osteolysis are crucial for the satisfactory long-term survival of TAA.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Definition of Periprosthetic Osteolysis in Shoulder Arthroplasty: A Systematic Review of Grading Schemes and Criteria

BACKGROUND

Periprosthetic osteolysis is a known complication after shoulder arthroplasty that may lead to implant loosening and revision surgery. To date, there is no consensus in the shoulder arthroplasty literature regarding the definition of osteolysis or the grading criteria, thus making it difficult to quantify and compare outcomes involving this complication. The purpose of this study was to perform a systematic review of the literature to assess how periprosthetic osteolysis in shoulder arthroplasty is defined and evaluated radiographically.

METHODS

A systematic review of MEDLINE, Scopus, Cochrane, and CINAHL was performed in August 2021 for studies that provided a definition and/or grading criteria for osteolysis in shoulder arthroplasty. Only studies with a minimum of 2 years of radiographic follow-up were included.

RESULTS

Thirty-four articles met the inclusion criteria. After consolidating studies by the same primary author that included the same grading criteria, 29 studies were examined for their definition and grading criteria for osteolysis. Of these, 19 (65.5%) evaluated osteolysis surrounding the glenoid and 18 (62.1%) evaluated osteolysis surrounding the humerus. There was considerable heterogeneity in the systems used to grade periprosthetic osteolysis surrounding the glenoid, whereas humeral periprosthetic osteolysis was often categorized via visualization into binary or categorical groups (e.g., presence versus absence; mild, moderate, or severe; partial versus complete). Four studies (13.8%) provided novel measurements for assessing either glenoid or humeral osteolysis.

CONCLUSIONS

Considerable heterogeneity exists in the assessment and grading of periprosthetic osteolysis in shoulder arthroplasty. The most common grading systems were binary and used qualitative visual interpretation, making them relatively subjective and prone to bias. Quantitative measurements of osteolysis were infrequently utilized. A standardized method of assessing osteolysis would be of value to facilitate communication and research efforts.

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.

Fixed-Bearing Trabecular Metal Total Ankle Arthroplasty Using the Transfibular Approach for End-Stage Ankle Osteoarthritis

This multicenter prospective cohort study assessed the safety and performance of the Trabecular Metal Total Ankle System (TM Ankle; Zimmer) for primary total ankle arthroplasty (TAA).

Low Rate of Peri-implant Osteolysis in Trabecular Metal Total Ankle Replacement on Short- to Midterm Follow-up

BACKGROUND

Peri-implant osteolysis is one of the major complications related to total ankle replacement. The aim of this study was to investigate the short- to midterm incidence of peri-implant osteolysis using computed tomography (CT) as imaging method for the Trabecular Metal Total Ankle (TMTA) implant representing a novel total ankle replacement (TAR) implant design regarding material and surgical technique.

METHODS

In total, 104 consecutive patients who had a primary TMTA replacement between March 2013 and October 2017 were included in the study. The radiographic evaluation included weightbearing anteroposterior and lateral views at baseline and after 3, 6, and every 12 months postoperatively. A helical CT was undertaken preoperatively and of the 80 patients available to follow up at least 12 months postoperatively, with average time interval between the TAR operation and the latest CT of 39 (range, 12-85) months.

RESULTS

Eight of 80 patients had altogether 11 osteolytic lesions around the components on CT images. Seven lesions were found in tibia, 3 in talus, and 1 in distal fibula. Four of the tibial lesions were situated in the medial malleolus and were not in contact with the prosthesis component. The sizes of the osteolytic lesions ranged between 7 and 20 mm, and the average volume of the lesions was 689 mm³.

CONCLUSION

We conclude that the risk of peri-implant osteolysis with the TMTA implant is minimal in short to midterm. The anatomic configuration, unique material, and surgical technique may all contribute to the TMTA implant having a low rate of peri-implant osteolysis.

LEVEL OF EVIDENCE

Level IV, case series.

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.