Outcomes of Bone Grafting of Bone Cysts After Total Ankle Arthroplasty

Bone grafting for periprosthetic bone cysts following total ankle arthroplasty

Aims

The purpose of this study was to assess the success rate and functional outcomes of bone grafting for periprosthetic bone cysts following total ankle arthroplasty (TAA). Additionally, we evaluated the rate of graft incorporation and identified associated predisposing factors using CT scan.

Methods

We reviewed a total of 37 ankles (34 patients) that had undergone bone grafting for periprosthetic bone cysts. A CT scan was performed one year after bone grafting to check the status of graft incorporation. For accurate analysis of cyst volumes and their postoperative changes, 3D-reconstructed CT scan processed with 3D software was used. For functional outcomes, variables such as the Ankle Osteoarthritis Scale score and the visual analogue scale for pain were measured.

Results

Out of 37 ankles, graft incorporation was successful in 30 cases. Among the remaining seven cases, four (10.8%) exhibited cyst re-progression, so secondary bone grafting was needed. After secondary bone grafting, no further progression has been noted, resulting in an overall 91.9% success rate (34 of 37) at a mean follow-up period of 47.5 months (24 to 120). The remaining three cases (8.1%) showed implant loosening, so tibiotalocalcaneal arthrodesis was performed. Functional outcomes were also improved after bone grafting in all variables at the latest follow-up (p < 0.05). The mean incorporation rate of the grafts according to the location of the cysts was 84.8% (55.2% to 96.1%) at the medial malleolus, 65.1% (27.6% to 97.1%) at the tibia, and 81.2% (42.8% to 98.7%) at the talus. Smoking was identified as a significant predisposing factor adversely affecting graft incorporation (p = 0.001).

Conclusion

Bone grafting for periprosthetic bone cysts following primary TAA is a reliable procedure with a satisfactory success rate and functional outcomes. Regular follow-up, including CT scan, is important for the detection of cyst re-progression to prevent implant loosening after bone grafting.

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.

Complications after total wrist arthroplasty

We reviewed the incidence and management of complications after total wrist arthroplasty, as reported in the literature, with so-called fourth-generation implants and other recent designs. While early intraoperative and postoperative complications, including fractures, tendon lacerations, infection, nerve compression, tendonitis, stiffness and chronic regional pain syndrome, had an acceptable incidence, late complications, such as periprosthetic osteolysis and implant loosening, occurred more frequently. Implant survival at 10 years was in the range of 70%-80% in most publications. Several of the implants have been modified or withdrawn. Instability and dislocation were frequent after a pyrocarbon spacer. Failed arthroplasties can be salvaged by revision arthroplasty or total wrist arthrodesis. Revision arthroplasty has a lower survival rate than primary arthroplasty and does not clearly offer important significant advantages over total wrist arthrodesis in terms of patient-reported outcome measures. Further development of prosthetic design, new materials and more knowledge on patient-related risk factors are needed.

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.

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.

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.

How Does a Novel In Situ Fixed-bearing Implant Design Perform in Revision Ankle Arthroplasty in the Short Term? A Survival, Clinical, and Radiologic Analysis

BACKGROUND

Given the growing number of primary total ankle replacements (TAR), an increase in the number of patients undergoing subsequent revisions might be expected. Achieving a stable and balanced ankle while preserving the remaining bone stock as much as possible is crucial for success in revision TAR. Most reported techniques rely on bulky implants with extended fixation features. Since 2018, we have used a novel, three-component ankle prosthesis for revision that is converted in situ to a fixed-bearing, two-component ankle prosthesis once the components have found their position according to an individual's anatomy. The results of this novel concept (fixation, revision, pain, or function) have not, to our knowledge, been reported.

QUESTIONS/PURPOSES

What are the short-term results with this new revision TAR design, in terms of (1) repeat revision surgery, (2) patient-reported outcomes on the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, (3) pain according to the VAS, and (4) radiographic signs of fixation?

METHODS

Between February 2018 and February 2020, we performed 230 TAR surgeries (in 206 patients) for any indication in our clinic. The novel semiconstrained, uncemented Hintermann Series H2 © implant was used in 96% (220 of 230) of procedures (201 patients). Fifty-four percent (119 of 220) of these were converted from an existing TAR to H2, which was the focus of the present study. However, only 45% (54 of 119) of these conversions to H2 were eligible for analysis. These patients had a mean age of 63 ± 12 years, and 43% (23 of 54) were women. The median (range) follow-up time was 3.2 years (2.0 to 4.3). The H2 design allows in situ conversion to a fixed-bearing system, with minimal bone resection. It achieves translational and rotational stability while preserving function and supporting the periarticular soft tissues. We defined repeat revision as exchange of one or both metal components, ankle fusion, or amputation and assessed it using a cumulative incidence survivorship estimator. Factors potentially associated with revision were assessed using Cox regression analyses. Clinical and radiologic outcomes were assessed preoperatively and at the most recent follow-up interval. Clinical outcomes included pain on the VAS (average pain during normal daily activity during the past seven days) and AOFAS score. Radiologic outcomes were the tibial articular surface angle, tibiotalar surface angle, talar tilt angle in the coronal plane, and AP offset ratio in the sagittal plane, as well as radiolucent lines and radiographic signs of loosening, defined as change in position greater than 2° of the flat base of the tibia component in relation to the long axis of the tibia, subsidence of the talar component into the talus greater than 5 mm, or change in position greater than 5° relative to a line drawn from the top of the talonavicular joint to the tuberosity of the calcaneus, as seen on plain weightbearing radiographs.

RESULTS

The cumulative incidence of repeat revision after 1 and 2 years was 5.6% (95% CI 0% to 11%) and 7.4% (95% CI 0% to 14%), respectively. With the numbers available, no clinical factors we analyzed were associated with the risk of repeat revision. The median values of all assessed clinical outcomes improved; however, not all patients improved by clinically important margins. The median (range) AOFAS ankle-hindfoot score increased (from 50 [16 to 94] to 78 [19 to 100], difference of medians 28; p < 0.01), and the median pain on the VAS decreased (from 5 [0 to 9] to 2 [0 to 9], difference of medians 3; p < 0.01) from before surgery to follow-up at a minimum of 2 years. Radiographically, lucency was seen in 12% (6 of 49 patients) and loosening was seen in 8% (4 of 49). One of these patients showed symptomatic loosening and was among the four patients overall who underwent revision. We could not assess risk factors for repeat revision because of the low number of events (four).

CONCLUSION

The investigated new in situ fixed-bearing ankle design achieved overall better short-term results than those reported in previous research. Destabilization of the ankle joint complex, soft tissue insufficiency, and possible changes of the joint configuration need an optimal solution in revision arthroplasty. The studied implant might be the answer to this complex issue and help surgeons in the perioperative decision-making process. However, a relatively high percentage of patients did not achieve a clinically important difference. Observational studies are needed to understand long-term implant behavior and possibly to identify ankles benefiting the most from revision.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

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.

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.

Treatment of Infected Nonunions With Bone Defects Using Autologous Bone Graft and Absorbable Antibiotic-Loaded Calcium Sulfate-Hydroxyapatite Paste

BACKGROUND

Revision surgery in the presence of infection carries high risks. We describe our results using a new technique to treat these challenging problems. We treated infected nonunions with cavitary voids with adjuvant antibiotic loaded calcium sulfate-hydroxyapatite paste composite and autologous bone graft (ABG) layer technique coupled with stable fixation.

METHODS

Thirty consecutive patients who underwent revision foot and ankle surgery for an infected nonunion were prospectively studied. Following multidisciplinary team workup, surgical debridement and biopsies were undertaken. Bone voids were measured and classified according to containment and size. ABG was mixed and layered with an adjuvant antibiotic-loaded calcium sulfate-hydroxyapatite paste followed by surgical reconstruction including arthrodesis and fixation. Empirical and pathogen-specific antibiotics were instituted until intraoperative sample-specific antibiotics were identified and used. Patients were prospectively followed up for a minimum of 1 year.

RESULTS

The male-female ratio was 16:14, mean age was 51.3 years, and 23.3% smoked at definitive surgery. Void volume was <1 cm³ (n=9), 1-2 cm³ (n = 13), and >2 cm³ (n=8). No patients either were lost to follow-up or had a further infective episode at a mean of 38.3 months; 86.7% united with fusion on imaging. Four patients had radiographic evidence of nonunion; 3 were asymptomatic and 1 required revision surgery (void >2 cm³). Independent ambulation was achieved at an average of 12 weeks, at 1 year mean American Orthopaedic Foot & Ankle Society score was 77.7 (SD 9.59), and the Manchester-Oxford Foot Questionnaire reached an effect size >0.5 in all domains at 1 year following surgery. The union rate was independent of smoking status and vitamin D deficiency (P = .94).

CONCLUSION

Layered autologous bone grafting with adjuvant antibiotic-loaded calcium sulfate-hydroxyapatite paste has been shown to be effective and safe in revision arthrodesis, with low comorbidities in void gaps without infection recurrence.

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.

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.

Analysis of 408 Total Ankle Arthroplasty Adverse Events Reported to the US Food and Drug Administration From 2015 to 2018

Background. Total ankle arthroplasty (TAA) use has increased with newer generation implants. Current reports in the literature regarding complications use data extracted from high-volume centers. The types of complications experienced by lower-volume centers may not be reflected in these reports. The purpose of this study was to determine a comprehensive TAA adverse event profile from a mandatory-reporting regulatory database. Methods. The US Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database was reviewed from 2015 to 2018 to determine reported adverse events for approved implants. Results. Among 408 unique TAA device failures, the most common modes of failure were component loosening (17.9%), intraoperative guide or jig error (15.4%), infection (13.7%), and cyst formation (12.7%). In addition, the percentage distribution of adverse event failure types differed among implants. Conclusion. The MAUDE database is a publicly available method that requires mandatory reporting of approved device adverse events. Using this report, we found general agreement in types of complications reported in the literature, although there were some differences, as well as differences between implants. These data may more accurately reflect a comprehensive profile of TAA complications as data were taken from a database of all device users rather than only high-volume centers.Levels of Evidence: NA.

Intermediate-term Patient-Reported Outcomes and Radiographic Evaluation Following Intramedullary- vs Extramedullary-Referenced Total Ankle Replacement

BACKGROUND

The purpose of this study was to report on the radiographic outcomes, clinical outcomes, and implant survivorship following extramedullary-referenced (EMr) vs intramedullary-referenced (IMr) total ankle replacement (TAR).

METHODS

From May 2007 to February 2018, a consecutive series of patients with end-stage tibiotalar osteoarthritis undergoing TAR was enrolled in this study. Analyses were performed comparing IMr vs EMr components for patient-reported outcomes data, pre- and postoperative radiographic ankle alignment, concomitant procedures, and complications. Kaplan-Meier survivorship analyses served to determine implant reoperation and revision surgery. A total of 340 TARs were included with 105 IMr TAR and 235 EMr TAR. The mean follow-up was 5.3 years (±2.5, range 2-12).

RESULTS

The absolute value for preoperative coronal alignment was significantly greater for IMr compared to EMr TAR (13.0 vs 6.4 degrees; P < .0001), but both groups achieved near neutral alignment postoperatively (1.4 vs 1.5 degrees; P = .6655). The odds of having a concomitant procedure was 2.7 times higher in patients with an IMr TAR (OR 2.7, CI 1.7-4.4; P < .0001). There were similar improvements in patient-reported outcome scores at 1 year and final follow-up (all P > .05). The 5-year implant survivorship was 98.6% for IMr vs 97.5% for EMr at final follow-up.

CONCLUSION

The IMr and EMr TAR components had comparable postoperative alignment, patient-reported outcome scores, and complications. The 5-year implant survivorship was similar between the IMr and EMr groups.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Endoprothetik am oberen Sprunggelenk

Arthrosis of the upper ankle is usually the long-term consequence of an ankle fracture. In the case of advanced osteoarthritis - after all conservative therapy options have been exhausted - the therapeutical options are reduced to the choice between arthrodesis and prosthesis, the technique and follow-up treatment of which this article presents. The mobility achieved after endoprosthetic treatment is usually less than the normal physiological level, but still functionally sufficient.

Pathogenesis, Evaluation, and Management of Osteolysis Following Total Ankle Arthroplasty

Periprosthetic osteolysis is a common occurrence after total ankle arthroplasty (TAA) and poses many challenges for the foot and ankle surgeon. Osteolysis may be asymptomatic and remain benign, or it may lead to component instability and require revision or arthrodesis. In this article, we present a current and comprehensive review of osteolysis in TAA with illustrative cases. We examine the basic science principles behind the etiology of osteolysis, discuss the workup of a patient with suspected osteolysis, and present a review of the evidence of various management strategies, including grafting of cysts, revision TAA, and arthrodesis.Level of Evidence: Level V, expert opinion.

Bone Cysts and Osteolysis in Ankle Replacement

BACKGROUND

Total ankle replacements (TARs) have higher rates of osteolysis than hip or knee replacements. It is unclear whether this is a pathologic immunologic process in response to wear debris, or expansion of pre-existing osteoarthritic bone cysts. We aimed to determine the incidence of bone cysts in patients with end-stage ankle arthritis prior to surgery and review the literature on bone cysts and osteolysis in relation to TAR.

METHODS

This is a descriptive/prevalence study in which all patients with end-stage ankle arthritis underwent plain radiographic imaging and computed tomographic (CT) scans prior to TAR surgery. Their imaging was assessed for the presence of cysts, measured on sagittal, axial, and coronal slices of the CT scan at the widest diameter. All cysts that would be removed as a result of the bone resection for the implant were excluded using digital analysis software. We assessed 120 consecutive patients with mean age of 63.4 years.

RESULTS

Seventeen patients (14%) did not have any bone cysts based on CT images. Ten patients (8%) had cysts that would have been completely removed by surgery, leaving 93 patients for analysis (78%). In 60% of these cases, the cysts were not seen on the plain radiographs. In 39 patients (33%), the cysts were greater than 5 mm in size. The medial (36%) and lateral malleoli (33%) were the most common location for the cysts (mean diameter 4.6±2.0 and 4.2±2.3 mm, respectively).

CONCLUSION

Bone cysts outside of the resection margins for a TAR were present in 78% of patients with ankle arthritis prior to undergoing surgery. In 30% of cases, cysts were greater than 5 mm in size. In 60% of cases, the cysts were not seen on plain radiographs. Preoperative 3-dimensional imaging can provide a foundation to observe and quantify cyst presence, expansion, and time of onset in the postoperative setting.

LEVEL OF EVIDENCE

Level IIc, diagnostic/prevalence study.

Outcomes of Total Ankle Arthroplasty in Ankles with >20° of Coronal Plane Deformity

BACKGROUND

A preoperative severe coronal plane deformity of >20° has been considered a contraindication for total ankle arthroplasty. We aimed to evaluate whether outcomes of total ankle arthroplasty in ankles with severe coronal plane deformity (20° to 35° of varus or valgus) are comparable with those with moderate deformity (5° to 15° of varus or valgus).

METHODS

A total of 148 consecutive ankles (142 patients) that underwent primary total ankle arthroplasty using the HINTEGRA prosthesis were included. The overall mean follow-up duration was 74 months (range, 24 to 160 months). We divided all patients into 2 groups according to the preoperative coronal plane tibiotalar angle: the severe group (36 patients, 41 ankles) and the moderate group (106 patients, 107 ankles). Clinical and radiographic outcomes were analyzed for intergroup differences, and multivariable regression was used to adjust for baseline characteristics. Patients in each group showed similar characteristics in mean age, sex, mean body mass index, and median follow-up duration.

RESULTS

At a mean follow-up of 74 months, we found no significant intergroup difference in the Ankle Osteoarthritis Scale pain and disability score, American Orthopaedic Foot & Ankle Society ankle-hindfoot score, Short Form-36 Physical Component Summary score, visual analog scale pain score, or ankle range of motion (p > 0.05). However, the final tibiotalar angle, talar tilt angle, and number of outliers were greater in the severe group (p < 0.05). Complication rates did not show a significant difference between the 2 groups (p > 0.05). The overall survival probability of the implant was 91.3% (92.3% in the severe group and 90.7% in the moderate group) (p = 0.354).

CONCLUSIONS

Total ankle arthroplasty in ankles with preoperative severe coronal plane deformity showed satisfactory and comparable clinical outcomes without increasing complication rates relative to those with moderate deformity in the intermediate-term follow-up. Our results suggested that total ankle arthroplasty may be considered in ankles with deformity of >20°.

LEVEL OF EVIDENCE

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

Peri-prosthetic bone cysts after total ankle replacement. A systematic review and meta-analysis

BACKGROUND

Periprosthetic cystic osteolysis is a well-known complication of total ankle replacement. Several theories have been proposed for its aetiology, based on individual biomechanical, radiological, histopathology and outcome studies.

METHODS

Studies that met predefined inclusion/exclusion criteria were analysed to identify literature describing the presence of peri-prosthetic ankle cystic osteolysis. Quantitative data from the selected articles were combined and statistically tested in order to analyse possible relations between ankle peri-prosthetic bone cysts and specific implant characteristics.

RESULTS

Twenty-one articles were elected, totalizing 2430 total ankle replacements, where 430 developed peri-prosthetic cystic osteolysis. A statistically significant association (P<.001) was found between the presence of bone cysts and non-anatomic implant configuration, hydroxyapatite-coating, mobile-bearing and non tibial-stemmed implants. No significant association existed between the type of constraining and the presence of cysts (P>.05).

CONCLUSIONS

Non-anatomic, mobile-bearing, hydroxyapatite-coated and non tibial-stemmed total ankle replacements are positively associated with more periprosthetic bone cysts.

Scandinavian Total Ankle Replacement: 15-Year Follow-up

BACKGROUND

Over the past decade, total ankle arthroplasty (TAA) has become a mainstay in the treatment of end-stage ankle arthritis. Currently in its fourth generation, the Scandanavian Total Ankle Replacement (STAR) is the only 3-piece mobile bearing ankle prosthesis available in the United States. Our current study reports implant survivorship at 15 years and patient outcomes for a subset of these survivors available for study.

METHODS

Eighty-four TAAs were performed between 1998 and 2000. Metal component survivorship at 15 years was calculated with a Kaplan-Meier curve. Twenty-four (29%) of 84 patients were available for participation with a minimum 15-year follow-up. Any radiographic changes were documented. All additional procedures and complications were recorded. Clinical findings, self-reported performance and pain evaluations, and AOFAS ankle/hindfoot scores were noted.

RESULTS

Metal implant survival was 73% at 15 years. Of the 24 patients available for clinical evaluation, 18 of 24 patients (70.7%) had no change in prosthetic alignment from the immediate postoperative radiograph. Only 1 subtalar fusion was required for symptomatic adjacent joint arthritis. Three patients sustained a broken polyethylene component. AOFAS scores improved from an average of 39.6 points preoperatively, to an average of 71.6. More than half (52.4%) of patients with retained implants required an additional surgical procedure; 3 required 2 additional procedures. The average time to subsequent procedure was 10.2 years.

CONCLUSION

Our small cohort demonstrated STAR ankles with retention at 9 years were highly likely to survive to 15 years, and patients continued to have significant improvement in pain relief and minimal decrease in function. At 15 years from TAA, metal survivorship was 73%. As with all ankle replacements, supplementary procedures were common.

LEVEL OF EVIDENCE

Level IV, case series.

Bone cyst formation after ankle arthroplasty may be caused by stress shielding. A numerical simulation of the strain adaptive bone remodelling

BACKGROUND

The history of total ankle arthroplasty (TAA) has different evolution steps to improve the outcome. The third generation implants show an overall 8-year survival rate up to 93%. The main reported reason for early failure of TAA is aseptic loosening, cyst formation is also frequently reported. The aim of the present study is to use the finite element (FE) method to analyze the adaptive bone remodeling processes, including cyst formation after TAA.

METHODS

Bone characteristics applied to the model corresponded to information obtained from computed tomography. Finite element models for the tibia and the talus were developed and implant components were virtually implanted.

RESULTS

The calculated total bone loss is 2% in the tibia and 17% in the talus. Cysts and areas of increased bone density were detectable dependent on prosthesis design in the tibia and talus.

CONCLUSION

Our FE simulation provides a theoretical explanation for cyst formation and increasing bone density depending on implant design. However, cysts are not mono-causal, histo-chemical reactions should also be considered. Further clinical studies are necessary to evaluate the relevance of cyst formation and therapeutic strategies.

Medium to long-term results of 130 Ankle Evolutive System total ankle replacements-Inferior survival due to peri-implant osteolysis

BACKGROUND

The study reports the medium to long-term results of 130 Ankle Evolutive System total ankle replacements operated at a single-centre. Previously high amount of peri-implant osteolysis was reported from the same material.

METHODS

Between 2002 and 2008 one hundred and thirty consecutive ankles replaced with AES ankle prosthesis were followed both radiologically and clinically.

RESULTS

The five-year survival was 87.3% (95% confidence interval (CI) 80.0-92.0%), and ten-year survival 74.9% (95% confidence interval (CI) 65.4-82.2%) at a median follow-up time of 96 months (range 2-161; 8 years). Peri-implant osteolysis was found in 91 (70%) ankles, marked in 78 (60%). 44 ankles (34%) have been revised by filling of the cavities, 24 (18%) by fusion, and 6 by further replacement, resulting in the revision rate of 58%. Osteolysis was the main reason for all revisions. The improvement of the Kofoed Score and pain points was significant (all p<0.0001), and the subjective patient satisfaction was good.

CONCLUSIONS

Outcome of the current study was seriously affected by osteolysis and is inferior compared to previous reports.

Are periprosthetic osteolytic lesions in ankle worth bone grafting?

BACKGROUND

We retrospectively evaluated the medium-term follow-up of bone grafting due to periprosthetic osteolytic lesions in ankles.

METHODS

34 ankles (32 patients) with total ankle arthroplasty (TAA) underwent re operation. Indications were large periprosthetic osteolytic lesions or continuous growing of the lesions. The osteolytic lesions were imaged by CT before reoperation and once a year after that. The mean CT follow-up after re operation was 3.8 years (range, 2-6.2 years). Patient's clinical outcome was also monitored.

RESULTS

Osteolysis continued to progress in 44 bone grafted lesions (68%) in CT follow-up. Pain (p=0.04) and location of the lesion (p=0.03) were associated with progression of osteolysis. In 18 bone grafted osteolytic lesions (28%) the radiological survival remained excellent. 25 out of 34 ankles showed improvement of the function after bone grafting.

CONCLUSIONS

There is no established treatment protocol for osteolysis around TAA. Bone grafting is one alternative in the treatment of osteolytic lesions.

Ratio of Range of Motion of the Ankle and Surrounding Joints After Total Ankle Replacement: A Radiographic Cohort Study

BACKGROUND

This study attempted to identify where motion occurs after total ankle replacement, the difference in range-of-motion contributions between fixed-bearing and mobile-bearing total ankle replacements, and the contribution of abnormal peritalar motion. We hypothesized that sagittal plane radiographic assessment would demonstrate that actual ankle motion through the prosthesis is less than the total arc of ankle motion that may be observed clinically secondary to contributions from adjacent joints.

METHODS

Patients underwent routine standardized weight-bearing maximum dorsiflexion and plantar flexion sagittal radiographs. Sagittal plane ankle and foot measurements were performed on each dorsiflexion and plantar flexion radiograph to determine the total arc of ankle motion, actual ankle motion through the prosthesis, motion through the subtalar and talonavicular joints, and midfoot motion. Motion radiographs were routinely made at 1 year postoperatively and at the time of the most recent follow-up. A minimum follow-up of 2 years was required of all patients.

RESULTS

There were 197 patients who met the inclusion criteria (75 INBONE, 52 Salto Talaris, and 70 STAR prostheses). The mean time to the latest radiographs (and standard deviation) was 42.9 ± 18.8 months. The mean actual ankle motion through the prosthesis was 25.9° ± 12.2°, which was significantly less (p < 0.001) than the mean total motion arc of 37.6° ± 12.0°. The motion of the ankle accounted for 68% of total range of motion, and motion of the peritalar joints accounted for 32%. There was no significant difference (p > 0.05) among the 3 prostheses or when comparing fixed and mobile-bearing designs for both ranges of motion.

CONCLUSIONS

This study demonstrates that actual ankle motion after total ankle replacement is approximately 12° less than the total arc of motion that might be observed clinically because of increased midfoot and subtalar motion.

LEVEL OF EVIDENCE

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

Operative Wound Complications Following Total Ankle Arthroplasty

BACKGROUND

Wound complications following total ankle replacement (TAR) potentially lead to devastating consequences. The aim of this study was to compare the operative and demographic differences in patients with and without major wound problems which required operative management. We hypothesized that increased tourniquet and operative time would negatively influence wound healing.

METHODS

We identified a consecutive series of 762 primary TARs performed between December 1999 and April 2014 whose data were prospectively collected. We then identified the subset of patients who required a secondary surgery to treat major wound complications (ie, operative debridement, split-thickness skin grafting, and soft tissue reconstruction). All patients requiring a second surgery had operative wound debridement. We then compared the demographics, operative characteristics, and functional scores to see if any differences existed between patients with and without major wound complications. Clinical outcomes including secondary procedures and implant failure rates were recorded.

RESULTS

Twenty-six patients (3.4%) had a total of 49 operative procedures to treat major wound issues. Eighteen patients had flaps and 14 had split-thickness skin grafts. The median time to operatively treating the wound was 1.9 (range: 0.5-12.5) months after the index TAR. The median follow-up time from the wound procedure was 12.7 (range: 1.2-170.8) months. Compared to the control group, patients with major wounds had a significantly longer mean surgery (214.8 vs 189.3 minutes, P = .041) time and trended toward a longer median tourniquet time (151 vs 141 minutes, P = .060). Patients without wound complications were more likely to have posttraumatic arthritis, whereas those with wound complications were more likely to have primary osteoarthritis ( P = .006). The control group trended toward having a higher mean BMI (29.5 vs 27.2, P = .056). There were 6 failures in the major wound complication cohort (23.1%), including 2 below the knee amputations.

CONCLUSION

Ankle wounds that required operative management had high failure rates and some resulted in devastating outcomes. We did not find any increase in major wound complications in those with various risk factors as identified by other studies. Given our data, we recommend limiting operative time. While correcting hindfoot and midfoot alignment is important for improving patient functionality and survivorship of the implant, thought should be given to staging the TAR if multiple pathologies are to be addressed at the time of surgery to limit operative time.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.