Intermediate-term Results of Mobile-bearing Total Ankle Replacement

Abstract

Background:

The literature analyzing total ankle replacement (TAR) results should be critically interpreted because studies made by the design surgeons are potentially subject to bias. European nondesigner surgeon studies reviewing the HINTEGRA TAR system are scarce in the literature. The present study is a European nondesigner surgeon study reviewing a consecutive series of 50 HINTEGRA TAR systems with a minimum follow-up of 2 years, focusing on clinical and radiographic outcomes.

Methods:

Fifty primary TAR procedures were performed between February 2008 and January 2012 by a single surgeon. Every patient underwent a standardized clinical and radiographic follow-up at 6 weeks, 3 and 6 months, and 1 year postoperatively and annually thereafter. The mean time to final follow-up was 45 months.

Results:

The mean American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale score significantly increased from 43.5 preoperatively to 83.8 postoperatively. Clinical range of motion of the ankle also improved from 23.3 degrees preoperatively to 28.3 degrees postoperatively. In 70% of the TAR procedures, the talar component was positioned anteriorly with respect to the tibial axis. Radiological evidence of osteolysis was identified in 24 ankles. The failure rate in the present series was 10%, which was defined as having major revision surgery within 4 years.

Conclusion:

The survival of the first 50 HINTEGRA TAR systems in this series was satisfactory from clinical and radiological points of view. However, the incidence of asymptomatic periprosthetic osteolytic lesions was quite high (24 ankles).

Level of Evidence:

Level IV, retrospective case series.

Keywords

total ankle replacement TAR periprosthetic osteolytic lesions

Ankle osteoarthritis (OA) is a progressive degenerative joint disease that is characterized by severe pain, loss of autonomy, diminished health-related quality of life, functional disability, and diminished physical ability to fulfill occupational duties of life in its end stage.^1,20,42 Self-reported physical function in patients with ankle OA using the SF-36 questionnaire is equivalent to or worse than that of patients with end-stage kidney disease or congestive heart failure.^1,42

Although ankle arthrodesis is the main operative treatment for end-stage ankle OA and provides good pain relief and a relatively well-documented long-term outcome,^14,16,48,49 total ankle replacement (TAR) is increasingly being recognized as an effective alternative.^17,55 To be successful, TAR should meet essential requirements such as minimal bone resection, extended bone support, appropriate balancing of the ankle ligaments, and minimal contact stresses within and around the prosthesis.²⁷ The 3-component unconstrained HINTEGRA TAR system (Newdeal, Lyon, France) appears to meet those needs by proposing a unique design that provides axial rotation and physiological flexion and extension mobility, inversion and eversion stability, and no intramedullary fixation of its tibial component.^5,6,27

European nondesigner surgeon studies reviewing the HINTEGRA TAR system are scarce in the literature and have limited sample sizes, which explains why the authors of those studies were unable to reach any firm conclusions about the HINTEGRA TAR system.^9,37,45,53 To the authors’ knowledge, the present study is one of the first European nondesigner surgeon studies reviewing a consecutive series of 50 procedures with the HINTEGRA TAR system with a minimum follow-up of 2 years, focusing on clinical and radiographic outcomes.

Methods

Study Design

This retrospective cohort study includes unilateral TAR with a minimum follow-up of 2 years. The inclusion criteria for TAR were primary OA, posttraumatic OA with an aligned or partially reducible deformity of the ankle and/or hindfoot, inflammatory arthritis affecting one or multiple joint sites, and hemochromatosis. The exclusion criteria for TAR were the following: neuromuscular disorders; neuroarthropathy; instability or malalignment that could not be addressed by additional procedures; vascular insufficiency; physically demanding jobs; significant skin conditions such as skin ulcers, skin grafts, or previous anterior wounds; and severe osteoporosis. Fifty primary TAR procedures (26 right ankles and 24 left ankles) were performed between February 2008 and January 2012 by a single senior orthopedic foot and ankle surgeon. The present consecutive series of TAR represents the surgeon’s first 50 HINTEGRA TAR systems and therefore includes any potential learning curve component. The surgeon had previous TAR experience since 2003 using various implants: AES (Ankle Evolutive System, Transystem, Nîmes, France) from 2003-2006 and Mobility (DePuy, Leeds, UK) from 2006-2008. The institutional review board approved the study.

Patients

The 50 patients (50% female and 50% male) had a mean age of 54.9 ± 12.2 years (median, 53 years; range, 30-77 years). The preoperative diagnosis was posttraumatic OA in 34 (68%) ankles, primary OA in 7 (14%) ankles, and arthritis due to inflammatory disease in 9 (18%) ankles. The 50 patients had a mean body mass index of 27.1 kg/m² (median, 26.5 kg/m²; range, 19.0-37.5 kg/m²). The comorbidities included smoking in 5 patients, history of smoking in 1 patient, high blood pressure in 15 patients, and type 2 diabetes in 2 patients.

Implant and Operative Procedure

The HINTEGRA TAR system is a cementless, nonconstrained 3-component system designed to provide intrinsic stability in the coronal plane against eversion-inversion^4,27 and to use all available bone surfaces for support.⁵⁴ A standardized operative technique was used in all patients as described by Hintermann et al.²⁷ Three patients who presented with concomitant painful OA in the adjacent joints, confirmed clinically and radiographically with the use of conventional radiographs and computed tomography (CT), underwent 2-stage surgery. The first stage was arthrodesis of the subtalar and/or talonavicular and/or calcaneocuboid joints depending on the location of painful OA. The second stage was implantation of the ankle prosthesis 6 weeks after arthrodesis. The main reason for 2-stage surgery was to avoid 4 to 6 weeks of immobilization of the ankle prosthesis, which could potentially negatively affect the functional recovery of the patient.

Reconstruction of the malaligned ankle was essential to restore and maintain proper bony alignment and muscle balance in order to increase the chances of the long-term survival of TAR. Therefore, associated procedures included 1 Dwyer calcaneal osteotomy, 1 medial calcaneal sliding osteotomy, 1 medial malleolus osteotomy, 4 tenolysis of the tibialis posterior muscle, 14 Strayer Achilles lengthening, 3 deltoid ligament release, and 1 ligamentoplasty with an allograft.

Postoperative Care^5,28

Standard protocol

A short leg splint was used to hold the ankle in a neutral position. After 48 hours, the dressing and splint were removed, and a short leg cast was applied for a period of 10 days. After the immobilization period, the cast was replaced with a walker boot that protected the ankle against eversion, inversion, and plantarflexion. At 3 weeks postoperatively, a 4-month rehabilitation program was initiated with passive and active ankle movement, walking exercises, stretching and strengthening of the triceps surae, and balance and proprioception exercises.

Modified standard protocol for patients with TAR associated with the aforementioned additional procedures

A short leg splint was used to hold the ankle in a neutral position. After 48 hours, the dressing and splint were removed, and a short leg cast was applied for a period of 4 to 6 weeks depending on the type of additional procedure that was performed. After the immobilization period, the cast was replaced with a stable functional brace, and a 4-month rehabilitation program was initiated as described for the standard protocol. Patients with TAR with only Strayer Achilles lengthening followed the standard protocol.

Postoperative protocol of 2-stage surgery

Patients requiring arthrodesis of the subtalar and/or talonavicular and/or calcaneocuboid joints, depending on the location of painful OA, postoperatively had a short leg cast for a period of 4 to 6 weeks. After implantation of the ankle prosthesis, the standard protocol was then followed.

Data Analysis

An independent reviewer (clinical scientist who specialized in foot and ankle research), who did not perform a TAR procedure on any included patients, conducted preoperative and postoperative evaluations. Every patient underwent a standardized clinical and radiographic follow-up at 6 weeks, 3 and 6 months, and 1 year postoperatively and annually thereafter. The mean time to final follow-up was 45 ± 13.4 months (median, 43 months; range, 24-72 months).

The overall revision rate of TAR, the rate of additional surgeries (such as arthroscopic debridement, subtalar arthrodesis), and the rate of arthrodesis after failed TAR were assessed. All patients underwent the same preoperative and postoperative evaluation protocol, which is composed of a clinical examination, functional assessment (American Orthopaedic Foot and Ankle Society [AOFAS] Ankle-Hindfoot Scale),³¹ radiographic x-rays, and helical CT. Each patient rated his or her pain postoperatively using the following scores: (1) no pain, (2) occasionally, (3) daily, and (4) severe, almost always present. The range of motion (ROM) of the ankle-hindfoot complex was measured using a hand goniometer along the lateral border of the leg and the foot as described by Kim et al.³⁰ The aim of preoperative ankle-hindfoot CT was to explore the bone quality, the areas of wear, and possible pre-existing subchondral cysts as well as the status of the neighboring joints. The x-ray assessment was composed of (1) a standardized anteroposterior (AP) ankle Méary view to measure the hindfoot axis (γ angle)³⁶ and the position of the tibial (α₁ angle) and talar (α₂ angle) implants with respect to the tibial axis³⁰; (2) a standardized weightbearing lateral foot (and ankle) view to measure the slope of the tibial component with respect to the tibial axis (β angle), the AP position of the talus with respect to the tibial axis, and the alignment of the talar component with respect to the tibial component³⁰; and (3) standardized weightbearing lateral foot (and ankle) and lateral supine dynamic views under maximal dorsiflexion and plantarflexion of the ankle (Figures 1 -3).

The bone-implant interface was assessed with a postoperative standardized weightbearing lateral ankle view. Postoperative ankle-hindfoot CT was systematically performed at 24 months. If the presence of an osteolytic lesion was seen on plain radiographs, ankle-hindfoot CT was performed earlier to more accurately define the lesion. Recent studies demonstrated that CT has superior sensitivity to detect and to quantify more accurately osteolytic lesions adjacent to metal implants compared to conventional radiography.^24,54 The standardized weightbearing AP ankle Méary view was not used to analyze the bone-implant interface because of anterior shield of the tibial component and the convex shape of the talar component.⁵⁴ Radiolucency was defined as a nonevolutionary and asymptomatic radiolucent line between the implant and the bone less than 2 mm wide.^8,40 We defined radiolucencies as pathological if they became evolutionary and symptomatic. Heterotopic ossification posterior to the distal tibia on lateral foot (and ankle) x-rays was graded according to the classification described by Choi and Lee.^12,34 Osteolysis was defined as a demarcated periprosthetic hypodense zone greater than 2 mm with no inner bone trabeculae that was not present preoperatively.^11,39,54 The size as well as the anatomic location of osteolysis was measured and located with the use of ankle-hindfoot CT. The ankle was subdivided into 5 zones (lateral tibia, medial tibia, lateral malleolus, medial malleolus, under the talar implant) in the AP view^8,40 and into 7 zones (tibia: anterior shield, around screws, loading plate, and posterior tip; talus: anterior, middle, and posterior) in the lateral view (Figure 4).⁵⁴ The size of each lesion was calculated by using the ellipse formula A = ¼ abπ (a = maximal length in the axial plane [mm], and b = maximum length in the sagittal plane [mm]).⁵⁴ The total surface area of the lesion was than further classified as follows: type A: 0-200 mm²; type B: 200-400 mm²; and type C: more than 400 mm².⁴⁰ All radiographic measurements were conducted with AGFA IMPAX 6.5.3.657 software (AGFA Healthcare NV, Mortsel, Belgium).

Patients with and without osteolysis were further compared with regard to their demographics, clinical outcomes, and radiographic data to identify factors predisposing patients to develop periprosthetic osteolysis.

Statistical Methods

The Kolmogorov-Smirnov test was used to determine whether the chosen variables were normally distributed. Mann-Whitney U tests, Wilcoxon tests, or Student paired t tests were used for comparisons of nonnormally and normally distributed data. The χ² test was used to compare categorical variables. One-way ANOVA was used to assess differences in ROM and the AOFAS score between 3 subgroups of patients (group 1: AP offset ratio [AOR] > 1; group 2: AOR = 0; group 3: AOR < 1). A P value <.05 was considered significant. The correlation between the grades of heterotopic ossification and tibial component coverage was calculated by using the Spearman rank order correlation coefficient test. Data were analyzed using SPSS version 21 (SPSS Inc, Chicago, Illinois, USA).

Results

Clinical and Radiographic Results

The mean AOFAS score significantly (P < .0001) improved from 43.5 (median, 45; range, 19-58) preoperatively to 83.8 (median, 86.5; range, 60-97) postoperatively. The mean clinical ROM of the ankle also significantly increased from 23.3 degrees (median, 25 degrees; range, 10-35 degrees) preoperatively to 28.3 degrees (median, 30 degrees; range, 15-40 degrees) postoperatively (P < .05). Postoperatively, 25 patients reported having a painless ankle at their last follow-up. Nineteen patients occasionally experienced some pain, and 6 patients reported having daily pain at their ankle.

The radiological results are reported in detail in Table 1. Preoperative hindfoot alignment (median, 84.5 degrees; range, 71-104 degrees) differed significantly from postoperative hindfoot alignment (median, 86.5 degrees; range, 80-92 degrees) (P = .031). None of the TAR procedures had postoperative hindfoot alignment in varus (>94 degrees). The median radiological global ROM of TAR was 22 degrees (range, 5-37 degrees). The median postoperative α₁ angle of the tibial component was 91 degrees (range, 84-96 degrees). The slope of the tibial component (β angle) was 5 degrees of dorsiflexion (range, 0-12 degrees). The median postoperative α₂ angle of the talar component was 91 degrees (range, 84-96 degrees). The median AOR was 0.06 (range, –0.08 to 0.23). Seventy percent of the patients who underwent TAR had their talar component positioned anteriorly with respect to the tibial axis.

Table 1.

Radiographic Outcomes as Measured Preoperatively and Postoperatively.

	Preoperative	Postoperative	P Value
Hindfoot
Alignment, median (range)	84.5 (71 to 104)	86.5 (80 to 92)	.031
Coronal plane alignment, n (%)
Neutral (86-94 deg)	17 (34)	18 (36)	<.020
Varus (>94 deg)	2 (4)	0
Valgus (<86 deg)	31 (62)	32 (64)
Tibial component
α₁ angle, median (range)	90 (75 to 106)	91 (84 to 96)	.016
β angle, median (range)	N/A	5 (0 to 12)	N/A
Coronal plane alignment, n (%)
Neutral (86-94 deg)	32 (64)	47 (94)	<.010
Varus (>94 deg)	11 (22)	2 (4)
Valgus (<86 deg)	7 (14)	1 (2)
Talar component position
α₂ angle, median (range)	90 (80 to 119)	91 (83 to 95)	.149
Coronal plane alignment, n (%)
Neutral (86-94 deg)	37 (74)	46 (92)	<.050
Varus (>94 deg)	7 (14)	3 (6)
Valgus (<86 deg)	6 (12)	1 (2)
AOR, median (range)		0.06 (−0.08 to 0.23)
Sagittal position, n (%)
Central (0)	N/A	12 (24)
Anterior (>0)	N/A	35 (70)
Posterior (<0)	N/A	3 (6)
AOR following operative technique, median (range)	N/A	0 (−0.12 to 0.08)
Sagittal position, n (%)
Central (0)	N/A	25 (50)
Anterior (>0)	N/A	15 (30)
Posterior (<0)	N/A	10 (20)
Range of motion present at TAR, median (range)	N/A	22 (5 to 37)

Abbreviations: AOR, anteroposterior offset ratio; N/A, not applicable; TAR, total ankle replacement.

No significant differences were found in terms of ROM and the AOFAS score between the anteriorly, neutrally, and posteriorly positioned talar components with respect to the longitudinal axis of the tibia (P > .05 for 3 AOR subgroups and ROM; P > .05 for 3 AOR subgroups and AOFAS score).

The median AP position of the talar component with respect to the tibial component was 0 (range, –0.12 to 0.08). Only 10% of the TAR procedures had a posteriorly positioned talar component with respect to the tibial component.

Radiolucency, Heterotopic Ossification, and Osteolysis

Periprosthetic radiolucency was observed in 7 ankles (14%), all in the tibia (Table 2). The radiolucent lines less than 2 mm were located on the tibialis anterior shield in 2 TAR procedures, on the posterior part of the tibial component in 2 TAR procedures, and globally at the interface between the tibia and the tibial component in 3 TAR procedures.

Table 2.

Radiographic Outcomes: Radiolucency and Osteolysis.

	n (%)
Radiolucency
Absent	43 (86)
Present	7 (14)
Nonpathological	6 (12)
Pathological	1 (2)
Location
Tibialis anterior shield	2 (4)
Anterior part of the tibial component	0 (0)
Posterior part of the tibial component	2 (4)
Globally across the tibial component	3 (6)
Lateral malleolus	0 (0)
Medial malleolus	0 (0)
Osteolysis
Absent	26 (52)
Present	24 (48)
Total periprosthetic lesions in 24 ankles	66 (100)
Tibial component
Anteromedial	1 (2)
Anterolateral	3 (5)
Anterocentral	1 (2)
Centromedial	2 (3)
Centrolateral	5 (8)
Posteromedial	11 (17)
Posterolateral	7 (11)
Posterocentral	4 (6)
Lateral malleolus	2 (3)
Medial malleolus	6 (9)
Talar component
Anterior	11 (17)
Central	9 (14)
Posterior	4 (6)

Of the 50 TAR procedures, 24 ankles (48%) presented radiological evidence of heterotopic ossification, which was always located posterior to the tibial component (Table 3). There was no significant correlation between the extent of heterotopic ossification and tibial component coverage (r = −0.299).

Table 3.

Analysis of Heterotopic Ossification Versus Tibial Component Coverage.

	Heterotopic Ossification: Posterior Part of Tibial Component
Tibial Coverage	Grade 0	Grade 1	Grade 2	Grade 3	Grade 4	Total
Small (<2 mm), n	1	2	2	0	0	5
Optimal (−2 to 2 mm), n	20	8	5	4	3	40
Large (>2 mm), n	5	0	0	0	0	5
Total, n	26	10	7	4	3	r = −0.299^a

Spearman rank order correlation coefficient test.

Radiological evidence of osteolysis was identified in 24 ankles (48%). The mean time to the radiographic diagnosis of osteolysis was 27.7 months (range, 9-54 months). The incidence and location of osteolytic lesions are reported in Table 2. Sixty-six osteolytic lesions were detected in 24 ankles, which represent a mean of 2.5 lesions per ankle. Osteolytic lesions were first identified postoperatively within 12 months in 5 ankles, at 24 months in 7 ankles, at 36 months in 5 ankles, and more than 48 months in 7 ankles. Of the 66 osteolytic lesions, a total surface area less than 100 mm² (median, 38.1 mm²; range, 10-86.35 mm²) was found in 56 (84.8%) lesions, between 100 < X < 200 mm² in 8 (12.2%) lesions (median, 159.7 mm²; range, 102.1-193.1 mm²), between 200 < X < 300 mm² in 1 (1.5%) lesion, and more than 400 mm² in 1 (1.5%) lesion. There was no significant difference in pain between patients with or without osteolysis (χ² = 5.23; df = 3; P > .05).

Failure and Revision Surgery

Additional surgery was performed in 9 patients (18%), with a mean interval follow-up of 24.4 months. The most common operative indication for these additional surgeries was anteromedial gutter impingement (GI) (Table 4). The failure rate in the present series was 10%, defined as having major revision surgery within 4 years. In 2 ankles (4%), a component of the implant was replaced (Table 5), with a mean interval follow-up of 26 months. The main reasons for TAR component revision were ligamentous instability and a pathological radiolucent line between the posterior part of the tibial component and the tibial bone. On radiographs at recent follow-up, both prostheses were stable since revision surgery. Failure of the HINTEGRA TAR system that could not be managed by revision arthroplasty occurred in 3 patients (6%) due to an infection (1 ankle) and unexplained persistent pain (2 ankles) (Table 6). These failed TAR procedures were successfully converted to tibiotalar (2 cases) and tibiotalocalcaneal (1 case) arthrodeses. A bone allograft in association with an autograft from the iliac crest was used to fill the bone defect (Table 6). Radiological evidence of solid fusion was obtained after a mean time of 3 months.

Table 4.

Additional Surgery.

Case	Sex	Age, y	Original Indication	Time to Surgery, mo	Indication	Additional Procedures
1	M	46	PM OA	1	Infection	Lavage
2	F	36	PT OA	3	Medial retromalleolar pain	Neurolysis of tibialis posterior nerve
3	M	55	PT OA	12	Stress shielding (screws)	Screw removal
4	F	48	PT OA	24	Pain in medial malleolus	Medial sliding calcaneal osteotomy + supramalleolar osteotomy + Strayer
5	F	76	PM OA	25	Subtalar joint pain + pain in medial malleolus	Supramalleolar osteotomy + subtalar arthrodesis
6	F	53	RA OA	25	Anteromedial GI	Arthroscopic debridement + tenoscopy of tibialis posterior
7	F	49	PT OA	29	Anteromedial GI	Arthroscopic debridement
8	F	76	PT OA	41	Anteromedial GI	Arthroscopic debridement
9	F	56	PM OA	60	Anterior and posterior GI	Arthroscopic debridement

Abbreviations: F, female; GI, gutter impingement; M, male; PM OA, primary osteoarthritis; PT OA, posttraumatic osteoarthritis; RA OA, osteoarthritis due to inflammatory disease.

Table 5.

Prosthetic Revision Surgery.

Case	Sex	Age, y	Diagnosis	Reason for Failure	Time to Failure, mo	Revision Procedure	Graft
1	M	57	PM OA	Pathological tibialis posterior radiolucency	21	Revision tibial component	AlloS FH Sec + CA IC + DBM
2	F	58	PT OA	Ligamentous instability	31	Revision inlay from 6 to 9 mm	N/A

Abbreviations: AlloS, structural allograft; CA, cancellous bone; DBM, demineralized bone matrix; F, female; FH, femoral head; IC, iliac crest; M, male; N/A, not applicable; PM OA, primary osteoarthritis; PT OA, posttraumatic osteoarthritis; Sec, secured.

Table 6.

Tibiotalar and Tibiotalocalcaneal Fusion After Failed Total Ankle Replacement.

Case	Sex	Age, y	Diagnosis	Reason for Failure	Time to Failure, mo	Arthrodesis	Graft	Time to Fusion, mo	Hindfoot Deviation Valgus, deg	Follow-up, mo	AOFAS Score
1	F	65	PT OA	Infection	7	Tibiotalocalcaneal	AlloS FH Sec + CA IC + DBM	3	8	18	73
2	F	41	PT OA	Pain	21	Tibiotalar	AlloS FH + BM IC + DBM	3	5	12	75
3	F	54	PT OA	Pain	38	Tibiotalar	AlloS FH + BM IC + DBM	3	5	12	70

Abbreviations: AlloS, structural allograft; AOFAS, American Orthopaedic Foot and Ankle Society; BM, bone marrow; CA, cancellous bone; DBM, demineralized bone matrix; F, female; FH, femoral head; IC, iliac crest; PT OA, posttraumatic osteoarthritis; Sec, secured.

Discussion

The present cohort study evaluated multiple outcomes of TAR in 50 patients, performed by a single surgeon using the same operative approach and type of prosthesis. A detailed analysis indicates that clinical and radiological outcomes were satisfactory at a medium-term follow-up of 45 months. Significant improvements were observed in most clinical parameters including the AOFAS score and clinical ROM of the ankle. The present series had comparable AOFAS scores as reported in the literature (Supplementary Material 1). However, the amount of clinical ROM that significantly improved in the present series was not as high as reported in previous studies using the HINTEGRA prosthesis (Supplementary Material 2). The mean improvement in ROM of the literature review presented in Supplementary Material 2 was approximately 12.08 degrees, with a wide range of 3.4 to 25.28 degrees. The number of complications and TAR failures were comparable to the outcomes reported by 2 recent systematic reviews.^22,55 However, a high rate of focal osteolysis was observed, which could potentially prejudice the long-term outcome.

One can observe from the recent medium- and long-term outcomes of various types of ankle prostheses that the number of patients with periprosthetic osteolysis after TAR has increased.^{8,24,29,32,40,46,54} Misalignment of the TAR components was pointed out as a potential risk factor for developing periprosthetic osteolytic lesions.^18,19,47 Studies suggested that frontal or sagittal misalignment of the TAR components between themselves or with respect to the tibial axis could cause a high concentration of forces acting in the interfaces between metal and bone and in the polyethylene liner, accelerating polyethylene wear and the subsequent development of osteolysis.^17,21,23 With the numbers available, there were no significant differences in the position of the TAR components between patients with and without radiological evidence of osteolysis in the present study (Table 7). Similar results were found in the study of Yoon et al,⁵⁴ who investigated the incidence and characteristics of periprosthetic osteolytic lesions and their association with radiological and clinical outcomes after TAR.

Table 7.

Postoperative Differences in TAR Positions in Patients With or Without Osteolysis.

	Osteolysis
	Absent (n = 26)	Present (n = 24)	P Value
Hindfoot
Coronal alignment, median (range)	87 (80 to 91)	86 (81 to 92)	NS
Tibial component
α₁ angle, median (range)	91 (88 to 96)	92 (84 to 96)	NS
β angle, median (range)	5.5 (1 to 10)	5.0 (0 to 12)	NS
Talar component position
α₂ angle, median (range)	91 (88 to 95)	91 (83 to 95)	NS
Postoperative AOR, median (range)	0.07 (−0.08 to 0.21)	0.05 (−0.02 to 0.23)	NS
AOR following operative technique, median (range)	0 (−0.12 to 0.07)	0 (−0.05 to 0.08)	NS

Abbreviations: AOR, anteroposterior offset ratio; NS, not significant; TAR, total ankle replacement.

Most of the ankles with radiological evidence of osteolysis presented no or limited progression (83.3%), and only 4 ankles demonstrated continuous progression over the study period. Despite the high number of ankles presenting osteolytic lesions, all patients were asymptomatic, and there were no significant differences in clinical outcomes between patients with and without osteolysis (Table 8). The lack of correlation between the presence of radiological osteolysis and the absence of clinical symptoms was also observed in total hip arthroplasty and received the name of “silent osteolysis.”³⁸ This observation could partially be explained by the measured size of the osteolytic lesions, which was limited and would not affect the intrinsic stability of the TAR components. However, these lesions possess the potential for later mechanical failure of the implant if the size continuously progresses.

Table 8.

Clinical and Radiological Outcomes for the First 25 (Series 1) and Last 25 Cases (Series 2).

	Series 1	Series 2	P Value
Clinical outcomes
Ankle ROM, median (range)
Preoperative	25 (10 to 35)	25 (10 to 35)	NS
Postoperative	30 (15 to 40)	30 (20 to 40)	NS
AOFAS score, median (range)
Preoperative	45 (19 to 58)	44 (19 to 58)	NS
Postoperative	84 (61 to 97)	87 (60 to 97)	NS
Radiological outcomes
Hindfoot (valgus <90 deg; varus >90 deg)
Coronal alignment, median (range)
Preoperative	85 (71 to 104)	84 (77 to 97)	NS
Postoperative	86 (80 to 89)	87 (82 to 92)	NS
Tibial component
α₁ angle, median (range)
Preoperative	89 (82 to 106)	90 (75 to 98)	NS
Postoperative	92 (87 to 96)	91 (84 to 96)	NS
β angle, median (range)	4 (1 to 12)	6 (0 to 12)	.010
Talar component
α₂ angle, median (range)
Preoperative	90 (80 to 105)	90 (82 to 119)	NS
Postoperative	91 (87 to 95)	91 (83 to 95)	NS
Postoperative AOR, median (range)	0 (−0.02 to 0.23)	0.1 (−0.08 to 0.22)	NS
AOR following operative technique, median (range)	0 (−0.04 to 0.07)	0 (−0.12 to 0.08)	NS
ROM present at TAR, median (range)	21 (5 to 37)	22 (12 to 36)	NS

Abbreviations: AOFAS, American Orthopaedic Foot and Ankle Society; AOR, anteroposterior offset ratio; NS, not significant; ROM, range of motion; TAR, total ankle replacement.

Recent studies demonstrated that CT had superior sensitivity to detect and to quantify more accurately osteolytic lesions adjacent to metal implants compared to conventional radiography.^24,54 Yoon et al⁵⁴ reported that the sensitivity of standard radiographs was 53% for identifying lesions of any size and 50% for those less than 100 mm². This could explain why studies using CT to analyze their TAR procedures usually had a greater incidence of osteolysis compared to studies that used standard radiographs.

Numerous biomechanical^18,50 and clinical studies^2,4 have highlighted the biomechanical consequences of sagittal misalignment of the prosthetic components on ankle motion as well as a high concentration of implant contact stresses. A recent study by Barg et al⁴ demonstrated a significantly higher AOFAS score and ankle motion in patients with an AOR of 0 compared to patients with an AOR greater or less than 0. However, with the numbers available, no significant correlation was found between the AOR and the postoperative AOFAS score or ankle ROM in the present series. This finding could be explained by the limited sample size in the present study and by the fact that, of the 50 operated ankles, 70% had an AOR greater than 0. This percentage should be interpreted with care because the median AOR of 0.06 corresponds to 3 mm. Similar AOR repartitions between anteriorly, neutrally, and posteriorly positioned talar components have been reported in the literature.¹¹ The percentage of TAR being precisely positioned on the longitudinal axis of the tibia in clinical surgeon designer studies was limited to 34.5% to 40%.^2,3 The high rate of anteriorly positioned talar components reported in the literature (Supplementary Material 1)^2,3 and present study can potentially be explained by the rationale of the operative technique of the HINTEGRA prosthesis. In contrast to other prosthesis designs, the HINTEGRA instrument has an operative guide for the implantation of the talar component, which is not dependent on the tibial rod. The purpose of the HINTEGRA talar guide is to respect the anatomy by implementing the talar component into the talus in such a way that the center of rotation of the talar component corresponds to the original center of rotation of the talus. The ideal position of the talar component according to the operative technique of the HINTEGRA prosthesis is described as follows: the center of rotation of the talar implant must be situated in between 40% to 45% of the length of the tibial component on the lateral x-ray. The median AOR following the operative technique is 0, which reassures the authors about the sagittal alignment of the prosthesis. However, it will be interesting to analyze in the future if these anteriorly positioned talar components with respect to the longitudinal axis of the tibia will have an impact on the survival rate of the prosthesis in the long term. At the present time, further statistical analysis revealed no significant differences in terms of ROM and the AOFAS score between the anteriorly, neutrally, and posteriorly positioned talar components with respect to the longitudinal axis of the tibia.

Based on the results of the present study, proper alignment of the prosthetic components does not always result in adequate ankle ROM. Nevertheless, we believe that even a minor misalignment of the prosthetic components could potentially cause an abnormal concentration of stresses in the interfaces between metal and bone and in the polyethylene liner, and also on the surrounding soft tissues, especially the ligaments in posttraumatic cases.⁴¹

Because TAR is a challenging procedure with a steep learning curve, the surgeon’s experience may substantially influence the outcome of TAR procedures.^33,41,43 The present series represented the first 50 HINTEGRA TAR systems implanted by the primary surgeon and could therefore potentially include any potential implantation learning curve of the HINTEGRA TAR system. Therefore, we subsequently analyzed if a learning curve could be detected by comparing the radiographic and functional outcomes of the last 25 procedures to the radiographic and functional outcomes of the first 25 procedures. The results of the present study are not in line with previous literature regarding the presence of a steep learning curve with the HINTEGRA TAR system (Table 8). The previous TAR experience of the senior surgeon with various types of prostheses could explain the contradictory results that have been found compared to the literature.

Four patients (8%) postoperatively developed anteromedial GI, which was successfully debrided by arthroscopy. This incidence of symptomatic GI after TAR in patients who did not undergo gutter resection at the time of implantation is similar to the 7% incidence reported in the study of Schuberth et al.⁴⁴ The present authors suggest performing prophylactic gutter resection at the time of implantation to reduce the risk of postoperative symptomatic GI.

Of the 50 ankles, 24 ankles (48%) presented radiological evidence of heterotopic ossification, which was always located posterior to the tibial component (Table 3). The development of heterotopic ossification is not uncommon and has also been observed in other types of prostheses, with a maximum incidence of 63%.^11,51 Our findings mirrored the results of Choi and Lee¹² that the presence of heterotopic ossification was not significantly associated with tibial component coverage. Recently, Lee et al³³ suggested that insufficient removal of the posterior capsule and periosteum of the distal tibia could be the cause of heterotopic ossification. These ossifications could potentially be a source of pain and stiffness in patients after TAR.¹⁰ However, in the present series, only 1 patient was experiencing pain from heterotopic ossification, which was arthroscopically debrided. Choi and Lee¹² showed that heterotopic ossification formation was not associated with the outcome after TAR. Surgeons should therefore be extremely cautious in attributing posterior pain symptoms of TAR to the presence of heterotopic ossification in the posterior ankle joint.

While the longevity and number of primary TAR procedures continue to increase, the number of publications addressing the issue of TAR failure has also increased.^{7,13,15,25,26,28,35} Regardless of the implant used, Gougoulias et al²² reported in a systematic review that the overall failure rate (with revision, arthrodesis, or amputation as the endpoint) was approximately 10% at 5 years, with a wide range of 0% to 32%. In the present study, 10% had to undergo major revision surgery within 4 years (revision of the implant or conversion to arthrodesis). The failure rate was not higher in patients with comorbidities. A short review of previous TAR studies using the HINTEGRA prosthesis showed similar results in terms of revision rates requiring revision arthroplasty or arthrodesis (Supplementary Material 1). Loosening of one or both prosthesis components^11,27,30,52 as osteolytic defects⁵⁴ was reported in the literature as major reasons of failure. One can observe from the short review of the literature that converting failed TAR to arthrodesis is considered to be the “gold standard” for salvage (Supplementary Material 1).^22,28 The rate of failed TAR converted to arthrodesis is reported in the majority of the studies. However, the reasons for this revision procedure are not well described.

There are some limitations in the present study. First, the present study was a retrospective study of consecutive patients. Second, the present sample was composed of a heterogeneous group of patients with respect to age and preoperative diagnosis. Despite the fact that clinical ROM was measured preoperatively and postoperatively, the present series measured radiological ROM only postoperatively. However, the description of radiological ROM present in the HINTEGRA prosthesis is rarely described in the literature (Supplementary Material 2). Finally, the limited sample size and the minimum follow-up period of 2 years may explain the fact that the authors were unable to reach any firm conclusions regarding the etiology of periprosthetic osteolytic lesions.

Conclusion

Total ankle replacement is a challenging procedure, and the outcome is influenced by many factors including preoperative diagnosis, psychological factors, position and stability of the TAR components, and the presence of OA in the adjacent joints or surrounding soft tissue. Despite the 10% rate of revision surgery performed by a single surgeon within the first 4 years, the survival of the first 50 HINTEGRA TAR systems at a mean of 45 months was satisfactory in comparison to the literature from clinical and radiological points of view (Supplementary Material 1). However, the incidence of periprosthetic osteolytic lesions was high.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Agel

Coetzee

Sangeorzan

Roberts

Hansen

. Functional limitations of patients with end-stage ankle arthrosis. Foot Ankle Int. 2005;26(7):537-539.

Barg

Elsner

Anderson

Hintermann

. The effect of three-component total ankle replacement malalignment on clinical outcome: pain relief and functional outcome in 317 consecutive patients. J Bone Joint Surg. 2011;93-A(21):1969-1978.

Barg

Elsner

Chuckpaiwong

Hintermann

. Insert position in three-component total ankle replacement. Foot Ankle Int. 2010;31(9):754-759.

Barg

Knupp

Anderson

Hintermann

. Total ankle replacement in obese patients: component stability, weight change, and functional outcome in 118 consecutive patients. Foot Ankle Int. 2011;32(10):925-932.

Barg

Knupp

Henninger

Zwicky

Hintermann

. Total ankle replacement using Hintegra, an unconstrained, three-component system: surgical technique and pitfalls. Foot Ankle Clin. 2012;17(4):607-635.

Barg

Zwicky

Knupp

Henninger

Hintermann

. Hintegra total ankle replacement: survivorship analysis in 684 patients. J Bone Joint Surg. 2013;95-A(13):1175-1183.

Berkovitz

Clare

Walling

Sanders

. Salvage of failed total ankle arthroplasty with fusion using cancellous allograft and internal fixation. Foot Ankle Int. 2011;32(5):493-501.

Besse

Brito

Lienhart

. Clinical evaluation and radiographic assessment of bone lysis of the AES total ankle replacement. Foot Ankle Int. 2009;30(10):964-975.

Besse

Colombier

Asencio

. Total ankle arthroplasty in France. Orthop Traumatol Surg Res. 2010;96(3):291-303.

10.

Buechel

Sr Buechel

Jr Pappas

. Eighteen-year evaluation of cementless meniscal bearing total ankle replacements. Instr Course Lect. 2002;51:143-151.

11.

Choi

Kim

Yeo

Song

. Comparison of the Hintegra and Mobility total ankle replacements: short-to-intermediate-term outcomes. Bone Joint J. 2013;95-B(8):1075-1082.

12.

Choi

Lee

. Heterotopic ossification after total ankle arthroplasty. J Bone Joint Surg. 2011;93-B(11):1508-1512.

13.

Deleu

Devos Bevernage

Maldague

Gombault

Leemrijse

. Arthrodesis after failed total ankle replacement. Foot Ankle Int. 2014;35(6):549-557.

14.

Demetriades

Strauss

Gallina

. Osteoarthritis of the ankle. Clin Orthop Relat Res. 1998;349(1):28-42.

15.

Doets

Zürcher

. Salvage arthrodesis for failed total ankle arthroplasty. Acta Orthop. 2010;81(1):142-147.

16.

Donatto

. Arthritis and arthrodesis of the hindfoot. Clin Orthop Relat Res. 1998;349(4):81-92.

17.

Easley

Adams

Jr Hembree

Deorio

. Current concepts review: results of total ankle arthroplasty. J Bone Joint Surg. 2011;93-A(15):1455-1468.

18.

Espinosa

Walti

Favre

Snedeker

. Misalignment of total ankle components can induce high joint contact pressures. J Bone Joint Surg. 2010;92-A(5):1179-1187.

19.

Fukuda

Haddad

Ren

Zhang

L-Q

. Impact of talar component rotation on contact pressure after total ankle arthroplasty: a cadaveric study. Foot Ankle Int. 2010;31(5):404-411.

20.

Glazebrook

Daniels

Younger

. Comparison of health-related quality of life between patients with end-stage ankle and hip arthrosis. J Bone Joint Surg. 2008;90-A(3):499-505.

21.

Goldberg

Sharp

Cooke

. Early failure in total ankle replacements due to component malposition: a report of two cases. Foot Ankle Int. 2009;30(8):783-787.

22.

Gougoulias

Khanna

Maffulli

. How successful are current ankle replacements? A systematic review of the literature. Clin Orthop Relat Res. 2010;468(1):199-208.

23.

Greisberg

Hansen

. Ankle replacement: management of associated deformities. Foot Ankle Clin N Am. 2002;7(4):721-736.

24.

Hanna

Haddad

Lazarus

. Evaluation of periprosthetic lucency after total ankle arthroplasty: helical CT versus conventional radiography. Foot Ankle Int. 2007;28(8):921-926.

25.

Henricson

Rydholm

. Use of a trabecular metal implant in ankle arthrodesis after failed total ankle replacement. Acta Orthop. 2010;81(6):745-747.

26.

Hintermann

Nunley

Christensen

Steck

Schuberth

. The failed total ankle. Foot Ankle Spec. 2013;6(6):434-440.

27.

Hintermann

Valderrabano

Dereymaeker

Dick

. The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles. Clin Orthop Relat Res. 2004;(424):57-68.

28.

Hintermann

Zwicky

Knupp

Henninger

Barg

. Hintegra revision arthroplasty for failed total ankle prostheses. J Bone Joint Surg. 2013;95-A(13):1166-1174.

29.

Kim

Choi

Kim

Lee

. Total ankle replacement in moderate to severe varus deformity of the ankle. J Bone Joint Surg. 2009;91-B(9):1183-1190.

30.

Kim

Knupp

Zwicky

Lee

Hintermann

. Total ankle replacement in association with hindfoot fusion: outcome and complications. J Bone Joint Surg. 2010;92-B(11):1540-1547.

31.

Kitaoka

Alexander

Adelaar

Nunley

Myerson

Sanders

. Clinical rating systems for the ankle-hindfoot, midfoot, hallux and lesser toes. Foot Ankle Int. 1994;15(7):349-353.

32.

Koivu

Kohonen

Sipola

Alanen

Vahlberg

Tiusanen

. Severe periprosthetic osteolytic lesions after the Ankle Evolutive System total ankle replacement. J Bone Joint Surg. 2009;91-B(7):907-914.

33.

Lee

Cho

Hur

Yoon

. Perioperative complications of HINTEGRA total ankle replacement: our initial 50 cases. Foot Ankle Int. 2008;29(10):978-984.

34.

Lee

Cho

Park

Song

Yoon

Seon

. Heterotopic ossification after primary total ankle arthroplasty. J Bone Joint Surg. 2011;93-A(8):751-758.

35.

McCoy

Goldman

Fragomen

Rozbruch

. Circular external fixator-assisted ankle arthrodesis following failed total ankle arthroplasty. Foot Ankle Int. 2012;33(11):947-955.

36.

Méary

Filip

Aubriot

Tomeno

. Etude fonctionnelle de la double arthrodèse du pied. Rev Chir Orthop. 1977;63(4):345-359.

37.

Preyssas

Toullec

Henry

Neron

Mabit

Brihault

. Total ankle arthroplasty. Three-component total ankle arthroplasty in Western France: a radiographic study. Orthop Traumatol Surg Res. 2012;98(4 Suppl):S31-S40.

38.

Puri

Wixson

Stern

Kohli

Hendrix

Stulberg

. Use of helical computed tomography for the assessment of acetabular osteolysis after total hip arthroplasty. J Bone Joint Surg. 2002;84-A(4):609-614.

39.

Rippstein

Huber

Coetzee

Naal

. Total ankle replacement with use of a new three-component implant. J Bone Joint Surg. 2011;93-A(15):1426-1435.

40.

Rodriguez

Devos Bevernage

Maldague

Deleu

Tribak

Leemrijse

. Medium term follow-up of the AES ankle prosthesis: high rate of asymptomatic osteolysis. Foot Ankle Surg. 2010;16(2):54-60.

41.

Saltzman

Amendola

Anderson

. Training and complications in total ankle arthroplasty. Foot Ankle Int. 2003;24(6):514-518.

42.

Saltzman

Zimmerman

O’Rourk

Brown

Buckwalter

Johnston

. Impact of comorbidities on the measurement of health in patients with ankle osteoarthritis. J Bone J Joint Surg. 2006;88-A(11):2366-2372.

43.

Schimmel

Walschot

Louwerens

. Comparison of the short-term results of the first and last 50 Scandinavian total ankle replacements: assessment of the learning curve in a consecutive series. Foot Ankle Int. 2014;35(4):326-333.

44.

Schuberth

Babu

Richey

Christensen

. Gutter impingement after total ankle arthroplasty. Foot Ankle Int. 2013;34(3):329-337.

45.

Schuh

Hofstaetter

Krismer

Bevoni

Windhager

Trnka

. Total ankle arthroplasty versus ankle arthrodesis: comparison of sports, recreational activities and functional outcome. Int Orthop. 2012;36(6):1207-1214.

46.

Schutte

Louwerens

. Short-term results of our first 49 Scandinavian total ankle replacements (STAR). Foot Ankle Int. 2008;29(2):124-127.

47.

Stamatis

Myerson

. How to avoid specific complications of total ankle replacement. Foot Ankle Clin. 2002;7(4):765-789.

48.

Thomas

Daniels

. Current concepts review: ankle arthritis. J Bone Joint Surg. 2003;85-A(5):923-936.

49.

Thomas

Daniels

Parker

. Gait analysis and functional outcomes following ankle arthrodesis for isolated ankle arthritis. J Bone Joint Surg. 2006;88-A(3):526-535.

50.

Tochigi

Rudert

Brown

McIff

Saltzman

. The effect of accuracy of implantation on range of movement of the Scandinavian total ankle replacement. J Bone Joint Surg. 2005;87-B(5):736-740.

51.

Valderrabano

Hintermann

Dick

. Scandinavian total ankle replacement: a 3.7-year average followup of 65 patients. Clin Orthop Relat Res. 2004;(424):47-56.

52.

Valderrabano

Pagenstert

Horisberger

Knupp

Hintermann

. Sports and recreation activity of ankle arthritis patients before and after total ankle replacement. Am J Sports Med. 2006;34(6):993-999.

53.

Willegger

Trnka

Schuh

. The Hintegra ankle arthroplasty: intermediate term results of 16 consecutive ankles and a review on the current literature. Clin Res Foot Ankle. 2013;2:1.

54.

Yoon

Lee

Choi

Lee

. Periprosthetic osteolysis after total ankle arthroplasty. Foot Ankle Int. 2014;35(1):14-21.

55.

Zaidi

Cro

Gurusamy

. The outcome of total ankle replacement: a systematic review and meta-analysis. Bone Joint J. 2013;95-B(11):1500-1507.

Supplementary Material

Please find the following supplemental material available below.

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Intermediate-term Results of Mobile-bearing Total Ankle Replacement

Abstract

Background:

Methods:

Results:

Conclusion:

Level of Evidence:

Keywords

Methods

Study Design

Patients

Implant and Operative Procedure

Postoperative Care5,28

Standard protocol

Modified standard protocol for patients with TAR associated with the aforementioned additional procedures

Postoperative protocol of 2-stage surgery

Data Analysis

Statistical Methods

Results

Clinical and Radiographic Results

Radiolucency, Heterotopic Ossification, and Osteolysis

Failure and Revision Surgery

Discussion

Conclusion

Footnotes

Declaration of Conflicting Interests

Funding

References

Supplementary Material

Postoperative Care^5,28