Functional Outcomes of Total Ankle Arthroplasty at a Mean Follow-up of 7.6 Years

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
James W. Brodsky ◽  
Daniel J. Scott ◽  
Samuel Ford ◽  
Scott Coleman ◽  
Yahya Daoud
Keyword(s):  
Functional Outcomes ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthroplasty

scholarly journals Heterotopic Ossification in Total Ankle Arthroplasty

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0002
Author(s):  
Thomas Bemenderfer ◽  
Robert Anderson ◽  
Mario Escudero ◽  
Feras Waly ◽  
Kevin Wing ◽  
...  
Keyword(s):  
Systematic Review ◽  
Range Of Motion ◽  
Functional Outcome ◽  
Heterotopic Ossification ◽  
Functional Outcomes ◽  
Total Ankle Arthroplasty ◽  
Minimal Clinical Important Difference ◽  
Ankle Arthroplasty ◽  
Wide Range

Category: Ankle Arthritis Introduction/Purpose: Heterotopic ossification (HO) following total ankle arthroplasty (TAA) is a known sequela and has been reported to contribute to reduced postoperative range of motion and poor patient functional outcomes. However, conflicting results have been reported in the literature with respect to the correlation between HO and clinical outcome. As new strategies and implants continue to be designed, it is important to understand what instruments for measuring the outcome of treatment are important to assess when evaluating outcome measures in TAA. The present study documents the incidence of HO and functional outcome for the novel 2 component fixed bearing Infinity Total Ankle System prosthesis at minimum of two year follow up and reports a systematic review of the literature. Methods: We reviewed the incidence, degree of severity, and functional outcome in 67 consecutive patients who underwent primary Infinity TAA at two North American tertiary medical centers between 2013 and 2015 in a prospective observational study. Radiographic and functional outcome data was collected preoperatively, at 6 to 12 months postoperatively, and annually thereafter. In addition, we conducted a systematic review of studies reporting the incidence of HO following TAA. We included peer-reviewed studies reporting on at least 20 TAAs with minimum follow up of two years. Results: While the incidence of HO was 68% at 2.4 years in the 67 patients who underwent primary Infinity TAA, there was no association between HO and AOFAS (HO 73.9, no HO 55.0), SF36-PCS (HO 50.1, no HO 45.2), FFI (HO 22.1, no HO 26.4), and VAS (HO 2.6, no HO 2.3). Fourteen studies with 1201 TAAs were included. The overall incidence of HO following TAA was approximately 56.6% at average 3.8 years with a wide range (range, 22.2-100%). Four studies (299 ankles) did not address functional outcomes. Nine studies (822 ankles) reported no association between functional outcomes and HO. One study (80 ankles) reported a statistically significant difference in range of motion of 7 degrees of dorsiflexion and a 7-point difference in AOFAS score. Conclusion: There was no association between HO and functional outcome in our observational cohort. Only one study demonstrated statistically significant differences in range of motion and functional outcome due to HO. Although the minimal clinical important difference in ankle dorsiflexion and AOFAS has not been established in TAA, these differences are below the minimal clinical important difference established in other foot and ankle procedures. Available data, including the results in our 67 patients, suggests that clinical function is independent of the presence of HO.

scholarly journals Long Term Functional Outcomes after Total Ankle Arthroplasty

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0014
Author(s):  
James W. Brodsky ◽  
Daniel J. Scott ◽  
Samuel E. Ford ◽  
Scott Coleman ◽  
Yahya Daoud
Keyword(s):  
Gait Analysis ◽  
Functional Outcomes ◽  
Walking Speed ◽  
Step Length ◽  
Total Ankle Arthroplasty ◽  
Initial Contact ◽  
Ankle Arthroplasty ◽  
Objective Functional

Category: Ankle; Ankle Arthritis; Hindfoot Introduction/Purpose: In vivo gait analysis is the objective functional measurement compared to subjective patient-reported outcomes. Intermediate-term gait studies showed positive results of Total Ankle Arthroplasty (TAA). To date, there are no published Long-Term functional outcomes of TAA. Methods: Three-dimensional gait analysis with twelve-camera digital-motion capture system and double force plates recorded temporal-spatial (TS), kinematic (KM), and kinetic (KN) measures, in 33 patients who had STAR (28) or Salto Talaris (5) TAA, done pre-operatively and at intervals post-operatively, with last testing at a mean of 7.6 years. Almost half the patients had 8-13 year follow up. Results: Improvements were found in multiple gait parameters, with TS increases in cadence, (+9.5 steps/min; P <0.001), step length (+4.4 cm; P = 0.001) and walking speed (+0.2 m/s; P<0.001), KM increases in total ROM (+2.0 deg; P = 0.026), plantarflexion at initial contact (+2.7 deg; P=0.004), and maximum plantarflexion (+2.0 deg; P=0.049), and KN analysis showed no loss of ankle power, despite patients’ aging. When examining 15 patients with 8 to 13 year follow-up (mean 10.3 years), there were gains in cadence (+9.8 steps/min, p=0.003), step length (3.6 cm, p=0.024), and walking speed (0.17 m/s, p=0.003), and preservation of the increased sagittal ROM of 2.0 deg. The only difference between prostheses was increased dorsiflexion at initial contact in the STARs vs SALTOs (5.9 degrees, p=0.014). Conclusion: This is the first study to report long-term, objective, functional outcomes of TAA, as measured by 3-D digital gait analysis. Even at a decade or more after TAA, patients had sustained improvement in multiple, objective parameters of gait compared to their preoperative function.

scholarly journals Salvage Arthrodesis with Femoral Head Allograft for Failed Total Ankle Arthroplasty

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0032
Author(s):  
Hong S. Lee ◽  
Kiwon Young ◽  
Tae-Hoon Park ◽  
Hong Seop Lee
Keyword(s):  
Femoral Head ◽  
Subjective Assessment ◽  
Total Ankle Arthroplasty ◽  
Bone Block ◽  
Ankle Arthroplasty ◽  
Pain Scores ◽  
Walking Aids ◽  
The Mean ◽  
Final Followup

Category: Ankle Introduction/Purpose: Failed total ankle arthroplasty (TAA) often results in significant bone loss and requires salvage arthrodesis. The aim of this study was to investigate the outcomes of Salvage arthrodesis with allo-bone block for failed TAA. Methods: This study included 8 patients who underwent salvage arthrodesis with femoral head allograft for failed TAA from August 2012 to March 2018 because of loosing of TAA implant. The mean age of the patients was 71 years (range, 54-81 years), and the mean follow-up period was 32 months (range, 12 to 84 months). Allograft problem and alignment of joint were evaluated radiographically. American Orthopaedic Foot & Ankle Society (AOFAS) scores, Foot and Ankle Outcome Score (FAOS), and visual analogue scale (VAS) pain scores were recorded preoperatively and at the time of final followup. Functional questionnaires were used to assess the duration for which the patient could walk continuously, use of walking aids, consumption of pain medication, and the patient’s subjective assessment of the percentage of overall improvement compared with before the salvage arthrodesis. Results: The allograft was retained without collapse for a mean of 24 months (range, 12 to 36 months) in four patients. Collapse of the allograft was observed in four patients at a mean of 11 months (range, 9 to 16 months), 1 of 4 patients were conserved to retrograde intramedullary nail at postoperative 12 months because of with implant failure and nonunion. The mean AOFAS and VAS pain scores improved from 12 (range, 8 to 40) preoperatively to 63 (range, 38 to 75) postoperatively (p = 0.001) and from 7 (range, 6 to 10 to 3 (range, 2 to 8) (p = 0.001), respectively. At the final follow-up evaluation, 6 of 8 patients were able to walk continuously at least 30 minutes with walking aid. Conclusion: The successful rate of salvage arthrodesis with femoral head allograft was 75% (Six of total 8 patients). The incidence rate of allograft collapse was 50% (Four of total 8 patients).

scholarly journals Effect of Travel Time and Distance on Outcomes in Total Ankle Arthroplasty

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0015
Author(s):  
Kristin C. Caolo ◽  
Scott J. Ellis ◽  
Jonathan T. Deland ◽  
Constantine A. Demetracopoulos
Keyword(s):  
Travel Time ◽  
Complication Rate ◽  
High Volume ◽  
Total Ankle Arthroplasty ◽  
Complication Rates ◽  
Linear Regression Models ◽  
Ankle Arthroplasty ◽  
Significant Difference ◽  
Drive Time

Category: Ankle; Ankle Arthritis Introduction/Purpose: Surgeons who perform a higher volume of total ankle arthroplasty (TAA) are known to have decreased complication rates; evidence shows that low volume centers performing TAA have decreased survivorship when compared with high volume centers. Understanding differences in outcomes for patients traveling different distances for their TAA is important for future patients deciding where to travel for their surgery. No study has previously examined differences in outcomes of patients traveling different distances to a high volume center for their TAA. This study compares preoperative and postoperative PROMIS scores for patients undergoing total ankle arthroplasty who traveled less than and more than 50 miles for their TAA. We hypothesized that there would be no difference in outcome scores based on distance traveled or estimated drive time. Methods: This study is a single center retrospective review of 162 patients undergoing primary total ankle arthroplasty between January 2016 and December 2018. We collected the primary address as listed in the patient’s medical record and used the directions feature on Google Maps to estimate driving mileage and estimated driving time from the patient’s address to the hospital. To analyze the distance patients traveled, patients were divided into two groups: <50 miles traveled (n=91) and >50 miles traveled (n=71). To analyze the estimated drive time, patients were divided into two groups: <90 minutes (n=77), >90 minutes (n=85). We collected preoperative and most recent postoperative PROMIS scores for all patients. Differences in most recent post-operative PROMIS scores between distance groups and travel time groups were assessed using multivariable linear regression models, adjusting for the pre-operative score and follow-up time. Results: We found no significant difference in post-operative PROMIS scores between the two groups when analyzed for distance traveled or for estimated travel time after adjustment for pre-operative PROMIS score and follow-up time (Table 1). The average follow-up for all 162 patients was 1.49 years. Power analysis showed that with a sample size of 110 (55 in each group), we had 81% power to detect an effect size of 4. Patients saw an increase in their Physical Function scores and a decrease in their Pain Interference and Pain Intensity scores with postoperative scores better than population means (Table 1). Overall complication rate for the <50 miles group was 17.6%, 7.7% required surgery. The >50 miles group had an overall complication rate of 24.0%, 9.9% required surgery. Conclusion: Patients traveling further distances to a high volume orthopedic specialty hospital for their total ankle arthroplasty do not have different clinical outcomes than patients traveling shorter distances. This is particularly important for patients deciding where to have their total ankle arthroplasty surgery. Patients who travel further have the opportunity to be treated at a local academic center; however our results show that outcomes do not change when traveling further for total ankle arthroplasty. [Table: see text]

scholarly journals Axial Rotational Alignment of Mobile-Bearing Total Ankle Arthroplasty

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0021
Author(s):  
Beat Hintermann ◽  
Lukas Zwicky ◽  
Christine Schweizer ◽  
Alexej Barg ◽  
Roxa Ruiz
Keyword(s):  
Tibial Component ◽  
Mobile Bearing ◽  
Total Ankle Arthroplasty ◽  
Axial Position ◽  
Anterior Surface ◽  
Ankle Arthroplasty ◽  
Medial Border ◽  
Wide Range ◽  
Angle Of Rotation

Category: Ankle Arthritis Introduction/Purpose: In total ankle arthroplasty (TAA), component malpositioning is a major cause of implant failure, possibly due to the altered force patterns caused by the malpositioning which are then transmitted to the bone-implant interface or neighboring joints during physiological loading. Mobile-bearing TAA with their second interface, may allow the talus to adapt its position based upon the individual anatomy. However, no data exist on the change in component positioning after implantation. It is unclear whether it is the result of initial positioning during implantation or secondary adjustments such as possible soft tissue adaptions. We aimed to determine the relative axial rotation between the talar and tibial components at the end of surgery and after a minimum of 3 years follow-up. Methods: The relative rotation between the tibial and talar components was measured in two groups. First, intraoperatively before wound closure, in a consecutive series of 58 patients (60 ankles; age 61.8 [31 to 86] years; females 25, males, 35) who underwent TAA between February and November 2018. A K-wire inserted along the medial border of the tibial component and a rectangular marker positioned at the anterior surface of PE insert were used to determine the angle of rotation. Second, in 48 patients (48 ankles; age 60.2 [31 - 82] years; females, 24; males, 24) out of 1411 patients who underwent TAA between January 2003 and December 2015, and in whom a weight-bearing CT scan was taken for evaluation at 6.3 (range, 3.0 -16.3) years. The medial border of the tibial component and a perpendicular line to the anterior surface of the PE insert were used to determine the angle of rotation. Results: The angle of rotation, thus the relative position of the talar component compared to the tibial component, did not differ between the two groups (p = 0.2). While the talus was internally rotated by 1.7 (range, -14.0 - 14.0) degrees at the end of surgery, it was internally rotated by 1.5 (range, -13.0 – 19.5) degrees after a minimum follow-up of 3 years (Figure 1). Conclusion: Although there was no significant difference in average axial position measured intraoperatively compared to a 3- years follow-up, there was a wide range of rotational measurements. The possibility of the talar component to find its position as given by individual anatomy may be crucial in TAA to avoid non-physiological joint loads and shear forces which may otherwise result in increased PE wear. Due to the wide range of measurements, our data suggests that axial talar rotation cannot be predicted preoperatively or intraoperatively by surgical techniques that reference the transtibial axis, tibial tuberosity and transmalleolar axis as guidance for tibial component positioning.

scholarly journals Role of Total Ankle Arthroplasty in Stiff Ankles – Long Term Follow-Up

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0001
Author(s):  
James W. Brodsky ◽  
Justin M. Kane ◽  
Andrew W. Pao ◽  
David D. Vier ◽  
Scott Coleman ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Step Length ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthritis ◽  
Ankle Arthroplasty ◽  
Post Surgery ◽  
Long Term Follow Up ◽  
Gait Function

Category: Ankle, Ankle Arthritis Introduction/Purpose: Operative treatment of end-stage ankle arthritis involves either ankle arthrodesis (AA) or total ankle arthroplasty (TAA). The theoretical benefit of TAA is the ability to preserve range of motion (ROM) at the tibiotalar joint. Previous studies have questioned whether it is justified to perform TAA over AA in stiff, arthritic ankles. However, a recent study showed that patients who underwent TAA with stiff ankles preoperatively experienced significant clinical improvement in range of motion and gait function compared to more flexible groups at 1-year follow-up. We retrospectively assessed these same gait and functional parameters to see if these improvements held up in long-term follow-up. Methods: A retrospective study of long-term, prospectively collected functional gait data in 33 TAA patients at a mean of 7.6 years postoperatively (range 4.8-13.3) used a multivariate regression model to determine the effect of ankle stiffness on the long- term, objective outcomes of TAA. Data was analyzed by quartiles (Q1, Q2+Q3, Q4) of preoperative sagittal ROM using one-way analysis of variance (ANOVA) to compare both preop and postop gait parameters. The two middle quartiles were combined to conform to distribution of the data. The multivariate analysis determined the independent effect of age, gender, BMI, years post- surgery, and preop ROM on every preop and postop parameter of gait. Results: Statistically significant differences were found in all three gait parameter categories, including temporal-spatial (step length and walking speed), kinematic (total sagittal ROM and maximum plantarflexion), and kinetic (peak ankle power). The stiffest ankles preoperatively (Q1) had the greatest absolute increase in total sagittal ROM postoperatively, +5.3o, compared to -1.3o (p<0.0174) in Q4 (most flexible). However, Q1 had the lowest absolute total postoperative sagittal ROM of 13.1 o, compared to 19.7 o (p<0.0108) in Q4. Q1 also had the lowest preoperative step length, walking speed, maximal plantarflexion, and peak ankle power when compared to the other subgroups. There was no difference in any of these same parameters postoperatively. BMI and years post-surgery had no effect on outcomes, while age and gender had a minimal effect. Conclusion: Preoperative range of motion was once again predictive of overall postoperative gait function in long-term follow-up at an average of 7.2 years. A greater degree of preoperative sagittal range of motion was predictive of greater postoperative sagittal range of motion in long-term follow-up. Patients with the stiffest ankles preoperatively once again had a statistically and clinically greater improvement in function as measured by multiple parameters of gait. This shows that the clinically meaningful improvement in gait function after total ankle arthroplasty holds up in long-term follow-up, even in the setting of limited preoperative sagittal range of motion.

scholarly journals Conversion of Ankle Fusions to Ankle Replacements

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0051
Author(s):  
Stephen White ◽  
Bruce Cohen ◽  
Carroll Jones ◽  
Michael Le ◽  
W. Hodges Davis
Keyword(s):  
Ankle Arthrodesis ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthritis ◽  
Ankle Arthroplasty ◽  
Patient Reported ◽  
Fusion Site ◽  
Foot Function ◽  
Patient Related Outcome ◽  
Improved Function

Category: Ankle Arthritis Introduction/Purpose: Ankle arthrodesis remains a prominent treatment choice for ankle arthritis in a majority of patients. Long term studies have shown a compensatory development of ipsilateral adjacent joint arthritis after ankle arthrodesis, and some patients who receive an ankle arthrodesis develop pain in surrounding joints, or even at the fusion site. As total ankle arthroplasty (TAA) design, instrumentation, and techniques have improved, the use of total ankle arthroplasty has become more widespread. Very few studies have been published on conversion of ankle arthrodesis to ankle arthroplasty, but they have shown improved function and patient-related outcome scores. The purpose of this study was to assess the radiographic, clinical, and patient-reported outcomes of patients undergoing ankle arthroplasty after conversion from a CT-confirmed ankle arthrodesis. Methods: This was a retrospective cohort study of patients with previous CT-confirmed ankle arthrodesis who underwent conversion to total ankle arthroplasty. Minimum follow up was 1 year. Nonunions of ankle arthrodesis were excluded. AOFAS ankle-hindfoot score, foot function index (FFI), pain, revision surgeries, complications, and patient demographics were assessed. Radiographs prior to TAA, and at latest follow-up were also reviewed. Results: 10 patients were included in the study with an average age of 54.5 years. No implants had to be revised. 1/10 (10%) patients had to undergo secondary surgery for heterotopic ossification removal. The same patient had to undergo another subsequent surgery for posterior ankle decompression. 2/10 (20%) patients had a mild talar subsidence of the TAA at latest follow-up, with no patients having tibial subsidence. Talar osteolysis was noticed in 2 patients (20%) at latest follow-up, with no patients having tibial osteolysis. Only one patient (10%) was noted to have a mild valgus alignment of TAA with no varus malalignments. All radiographic changes noted were clinically asymptomatic. The average AOFAS total score was 58 (range 23,89). The mean FFI total score was 41.9 (range 0,90). Conclusion: Conversion of ankle fusion to TAA is a challenging operation but can be a viable option for patients with ongoing pain after an ankle arthrodesis. We noted low revision rates and few complications at 1 year.

The Impact of Concomitant Ipsilateral Knee Pain on Functional Outcomes in Total Ankle Arthroplasty

2020 ◽  
pp. 193864002095089
Author(s):  
Michael J. Symes ◽  
Alastair Younger ◽  
Mario Escudero ◽  
Murray J. Penner ◽  
Kevin Wing ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Knee Pain ◽  
Functional Outcomes ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthritis ◽  
Pain Group ◽  
Ankle Arthroplasty ◽  
End Stage ◽  
The Impact ◽  
Disease Specific

In end-stage ankle arthritis, little is known about the impact of concomitant knee pathology, including the impact of ipsilateral knee pain on total ankle arthroplasty (TAA) outcomes. The aim of this study was to determine the prevalence of ipsilateral preoperative knee pain in patients undergoing TAA and analyze its impact on patient-reported functional outcome measures (PROMs). A retrospective review was performed on the Vancouver End Stage Ankle Arthritis Database at a single institution. In total, 114 patients were studied, with patient demographics collected preoperatively, including the presence or absence of knee pain. Postoperative follow-up was performed at 5 years, primarily analyzing disease-specific PROMs, including the Ankle Osteoarthritis Score (AOS) and Ankle Arthritis Score (AAS). Multivariate mixed-effects linear regression models compared the scores between the groups. In total, 31 patients (27.2%) presented with concomitant ipsilateral knee pain. Despite more females in the knee pain group (64.5% vs 36.1%) there were no other significant differences at baseline between the knee pain and no knee pain groups in terms of demographics or baseline primary disease specific PROMs. At 5 years, the patients with knee pain had significantly worse AAS (37.9 ± 23.8 vs 21.2 ± 16.3, P = .004) and AOS total scores (38.1 ± 24.1 vs 21.9 ± 15.5, P = .005) compared with the no-knee pain group. Both groups improved significantly from baseline across all outcome measures; however, the magnitude of improvement was less in the knee pain group. Our study demonstrated that over one-quarter of patients with end-stage ankle arthritis undergoing TAA present with ipsilateral concomitant knee pain. If present, it is associated with worse functional outcomes at the 5-year mark. Further studies are needed to evaluate if knee pain influences complications, implant failure rates, and survival. Levels of Evidence: Level III

Radiographic and Clinical Outcomes of the Salto Talaris Total Ankle Arthroplasty

2020 ◽  
Vol 41 (12) ◽  
pp. 1519-1528
Author(s):  
Jonathan Day ◽  
Jaeyoung Kim ◽  
Martin J. O’Malley ◽  
Constantine A. Demetracopoulos ◽  
Jonathan Garfinkel ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Case Series ◽  
Total Ankle Arthroplasty ◽  
Retrospective Case ◽  
Level Of Evidence ◽  
Ankle Arthroplasty ◽  
Patient Reported ◽  
The Mean ◽  
Component Revision

Background: The Salto Talaris is a fixed-bearing implant first approved in the US in 2006. While early surgical outcomes have been promising, mid- to long-term survivorship data are limited. The aim of this study was to present the survivorship and causes of failure of the Salto Talaris implant, with functional and radiographic outcomes. Methods: Eighty-seven prospectively followed patients who underwent total ankle arthroplasty with the Salto Talaris between 2007 and 2015 at our institution were retrospectively identified. Of these, 82 patients (85 ankles) had a minimum follow-up of 5 (mean, 7.1; range, 5-12) years. The mean age was 63.5 (range, 42-82) years and the mean body mass index was 28.1 (range, 17.9-41.2) kg/m2. Survivorship was determined by incidence of revision, defined as removal/exchange of a metal component. Preoperative, immediate, and minimum 5-year postoperative AP and lateral weightbearing radiographs were reviewed; tibiotalar alignment (TTA) and the medial distal tibial angle (MDTA) were measured to assess coronal talar and tibial alignment, respectively. The sagittal tibial angle (STA) was measured; the talar inclination angle (TIA) was measured to evaluate for radiographic subsidence of the implant, defined as a change in TIA of 5 degrees or more from the immediately to the latest postoperative lateral radiograph. The locations of periprosthetic cysts were documented. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared. Results: Survivorship was 97.6% with 2 revisions. One patient underwent tibial and talar component revision for varus malalignment of the ankle; another underwent talar component revision for aseptic loosening and subsidence. The rate of other reoperations was 21.2% ( n = 18), with the main reoperation being exostectomy with debridement for ankle impingement ( n = 12). At final follow-up, the average TTA improved 4.4 (± 3.8) degrees, the average MDTA improved 3.4 (± 2.6) degrees, and the average STA improved 5.3 (± 4.5) degrees. Periprosthetic cysts were observed in 18 patients, and there was no radiographic subsidence. All FAOS subscales demonstrated significant improvement at final follow-up. Conclusions: We found the Salto Talaris implant to be durable, consistent with previous studies of shorter follow-up lengths. We observed significant improvement in radiographic alignment as well as patient-reported clinical outcomes at a minimum 5-year follow-up. Level of Evidence: Level IV, retrospective case series.

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