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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 69 - 69
2 Jan 2024
Kvarda P Siegler L Burssens A Susdorf R Ruiz R Hintermann B
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Varus ankle osteoarthritis (OA) is typically associated with peritalar instability, which may result in altered subtalar joint position. This study aimed to determine the extent to which total ankle replacement (TAR) in varus ankle OA can restore the subtalar position alignment using 3-dimensional semi-automated measurements on WBCT. Fourteen patients (15 ankles, mean age 61) who underwent TAR for varus ankle OA were retrospectively analyzed using semi- automated measurements of the hindfoot based on pre-and postoperative weightbearing WBCT (WBCT) imaging. Eight 3-dimensional angular measurements were obtained to quantify the ankle and subtalar joint alignment. Twenty healthy individuals were served as a control groups and were used for reliability assessments. All ankle and hindfoot angles improved between preoperative and a minimum of 1 year (mean 2.1 years) postoperative and were statistically significant in 6 out of 8 angles (P<0.05). Values The post-op angles were in a similar range to as those of healthy controls were achieved in all measurements and did not demonstrated statistical difference (P>0.05). Our findings indicate that talus repositioning after TAR within the ankle mortise improves restores the subtalar position joint alignment within normal values. These data inform foot and ankle surgeons on the amount of correction at the level of the subtalar joint that can be expected after TAR. This may contribute to improved biomechanics of the hindfoot complex. However, future studies are required to implement these findings in surgical algorithms for TAR in prescence of hindfoot deformity.


The Bone & Joint Journal
Vol. 106-B, Issue 1 | Pages 46 - 52
1 Jan 2024
Hintermann B Peterhans U Susdorf R Horn Lang T Ruiz R Kvarda P

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.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_9 | Pages 12 - 12
17 Apr 2023
Van Oevelen A Burssens A Krähenbühl N Barg A Audenaert E Hintermann B Victor J
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Several emerging reports suggest an important involvement of the hindfoot alignment in the outcome of knee osteotomy. At present, studies lack a comprehensive overview. Therefore, we aimed to systematically review all biomechanical and clinical studies investigating the role of the hindfoot alignment in the setting of osteotomies around the knee.

A systematic literature search was conducted on multiple databases combining “knee osteotomy” and “hindfoot/ankle alignment” search terms. Articles were screened and included according to the PRISMA guidelines. A quality assessment was conducted using the Quality Appraisal for Cadaveric Studies (QUACS) - and modified methodologic index for non-randomized studies (MINORS) scales.

Three cadaveric, fourteen retrospective cohort and two case-control studies were eligible for review. Biomechanical hindfoot characteristics were positively affected (n=4), except in rigid subtalar joint (n=1) or talar tilt (n=1) deformity. Patient symptoms and/or radiographic alignment at the level of the hindfoot did also improve after knee osteotomy (n=13), except in case of a small pre-operative lateral distal tibia- and hip knee ankle (HKA) angulation or in case of a large HKA correction (>14.5°). Additionally, a pre-existent hindfoot deformity (>15.9°) was associated with undercorrection of lower limb alignment following knee osteotomy. The mean QUACS score was 61.3% (range: 46–69%) and mean MINORS score was 9.2 out of 16 (range 6–12) for non-comparative and 16.5 out of 24 (range 15–18) for comparative studies.

Osteotomies performed to correct knee deformity have also an impact on biomechanical and clinical outcomes of the hindfoot. In general, these are reported to be beneficial, but several parameters were identified that are associated with newly onset – or deterioration of hindfoot symptoms following knee osteotomy. Further prospective studies are warranted to assess how diagnostic and therapeutic algorithms based on the identified criteria could be implemented to optimize the overall outcome of knee osteotomy.

Remark: Aline Van Oevelen and Arne Burssens contributed equally to this work


The Bone & Joint Journal
Vol. 102-B, Issue 7 | Pages 925 - 932
1 Jul 2020
Gaugler M Krähenbühl N Barg A Ruiz R Horn-Lang T Susdorf R Dutilh G Hintermann B

Aims

To assess the effect of age on clinical outcome and revision rates in patients who underwent total ankle arthroplasty (TAA) for end-stage ankle osteoarthritis (OA).

Methods

A consecutive series of 811 ankles (789 patients) that underwent TAA between May 2003 and December 2013 were enrolled. The influence of age on clinical outcome, including the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score, and pain according to the visual analogue scale (VAS) was assessed. In addition, the risk for revision surgery that includes soft tissue procedures, periarticular arthrodeses/osteotomies, ankle joint debridement, and/or inlay exchange (defined as minor revision), as well as the risk for revision surgery necessitating the exchange of any of the metallic components or removal of implant followed by ankle/hindfoot fusion (defined as major revision) was calculated.


The Bone & Joint Journal
Vol. 101-B, Issue 6 | Pages 682 - 690
1 Jun 2019
Scheidegger P Horn Lang T Schweizer C Zwicky L Hintermann B

Aims

There is little information about how to manage patients with a recurvatum deformity of the distal tibia and osteoarthritis (OA) of the ankle. The aim of this study was to evaluate the functional and radiological outcome of addressing this deformity using a flexion osteotomy and to assess the progression of OA after this procedure.

Patients and Methods

A total of 39 patients (12 women, 27 men; mean age 47 years (28 to 72)) with a distal tibial recurvatum deformity were treated with a flexion osteotomy, between 2010 and 2015. Nine patients (23%) subsequently required conversion to either a total ankle arthroplasty (seven) or an arthrodesis (two) after a mean of 21 months (9 to 36). A total of 30 patients (77%), with a mean follow-up of 30 months (24 to 76), remained for further evaluation. Functional outcome, sagittal ankle joint OA using a modified Kellgren and Lawrence Score, tibial lateral surface (TLS) angle, and talar offset ratio (TOR) were evaluated on pre- and postoperative weight-bearing radiographs.


The Bone & Joint Journal
Vol. 100-B, Issue 4 | Pages 461 - 467
1 Apr 2018
Wagener J Schweizer C Zwicky L Horn Lang T Hintermann B

Aims

Arthroscopically controlled fracture reduction in combination with percutaneous screw fixation may be an alternative approach to open surgery to treat talar neck fractures. The purpose of this study was thus to present preliminary results on arthroscopically reduced talar neck fractures.

Patients and Methods

A total of seven consecutive patients (four women and three men, mean age 39 years (19 to 61)) underwent attempted surgical treatment of a closed Hawkins type II talar neck fracture using arthroscopically assisted reduction and percutaneous screw fixation. Functional and radiological outcome were assessed using plain radiographs, as well as weight-bearing and non-weight-bearing CT scans as tolerated. Patient satisfaction and pain sensation were also recorded.


The Bone & Joint Journal
Vol. 99-B, Issue 2 | Pages 231 - 236
1 Feb 2017
Wagener J Gross CE Schweizer C Lang TH Hintermann B

Aims

A failed total ankle arthroplasty (TAA) is often associated with much bone loss. As an alternative to arthrodesis, the surgeon may consider a custom-made talar component to compensate for the bone loss. Our aim in this study was to assess the functional and radiological outcome after the use of such a component at mid- to long-term follow-up.

Patients and Methods

A total of 12 patients (five women and seven men, mean age 53 years; 36 to77) with a failed TAA and a large talar defect underwent a revision procedure using a custom-made talar component. The design of the custom-made components was based on CT scans and standard radiographs, when compared with the contralateral ankle. After the anterior talocalcaneal joint was fused, the talar component was introduced and fixed to the body of the calcaneum.


The Bone & Joint Journal
Vol. 97-B, Issue 9 | Pages 1242 - 1249
1 Sep 2015
Hintermann B Wagener J Knupp M Schweizer C J. Schaefer D

Large osteochondral lesions (OCLs) of the shoulder of the talus cannot always be treated by traditional osteochondral autograft techniques because of their size, articular geometry and loss of an articular buttress. We hypothesised that they could be treated by transplantation of a vascularised corticoperiosteal graft from the ipsilateral medial femoral condyle.

Between 2004 and 2011, we carried out a prospective study of a consecutive series of 14 patients (five women, nine men; mean age 34.8 years, 20 to 54) who were treated for an OCL with a vascularised bone graft. Clinical outcome was assessed using a visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. Radiological follow-up used plain radiographs and CT scans to assess graft incorporation and joint deterioration.

At a mean follow-up of 4.1 years (2 to 7), the mean VAS for pain had decreased from 5.8 (5 to 8) to 1.8 (0 to 4) (p = 0.001) and the mean AOFAS hindfoot score had increased from 65 (41 to 70) to 81 (54 to 92) (p = 0.003). Radiologically, the talar contour had been successfully reconstructed with stable incorporation of the vascularised corticoperiosteal graft in all patients. Joint degeneration was only seen in one ankle.

Treatment of a large OCL of the shoulder of the talus with a vascularised corticoperiosteal graft taken from the medial condyle of the femur was found to be a safe, reliable method of restoring the contour of the talus in the early to mid-term.

Cite this article: Bone Joint J 2015;97-B:1242–9.


The Bone & Joint Journal
Vol. 97-B, Issue 5 | Pages 668 - 674
1 May 2015
Röhm J Zwicky L Horn Lang T Salentiny Y Hintermann B Knupp M

Talonavicular and subtalar joint fusion through a medial incision (modified triple arthrodesis) has become an increasingly popular technique for treating symptomatic flatfoot deformity caused by posterior tibial tendon dysfunction.

The purpose of this study was to look at its clinical and radiological mid- to long-term outcomes, including the rates of recurrent flatfoot deformity, nonunion and avascular necrosis of the dome of the talus.

A total of 84 patients (96 feet) with a symptomatic rigid flatfoot deformity caused by posterior tibial tendon dysfunction were treated using a modified triple arthrodesis. The mean age of the patients was 66 years (35 to 85) and the mean follow-up was 4.7 years (1 to 8.3). Both clinical and radiological outcomes were analysed retrospectively.

In 86 of the 95 feet (90.5%) for which radiographs were available, there was no loss of correction at final follow-up. In all, 14 feet (14.7%) needed secondary surgery, six for nonunion, two for avascular necrosis, five for progression of the flatfoot deformity and tibiotalar arthritis and one because of symptomatic overcorrection. The mean American Orthopaedic Foot and Ankle Society Hindfoot score (AOFAS score) at final follow-up was 67 (between 16 and 100) and the mean visual analogue score for pain 2.4 points (between 0 and 10).

In conclusion, modified triple arthrodesis provides reliable correction of deformity and a good clinical outcome at mid- to long-term follow-up, with nonunion as the most frequent complication. Avascular necrosis of the talus is a rare but serious complication of this technique.

Cite this article: Bone Joint J 2015; 97-B:668–74.


The Bone & Joint Journal
Vol. 96-B, Issue 6 | Pages 772 - 777
1 Jun 2014
Kessler B Knupp M Graber P Zwicky L Hintermann B Zimmerli W Sendi P

The treatment of peri-prosthetic joint infection (PJI) of the ankle is not standardised. It is not clear whether an algorithm developed for hip and knee PJI can be used in the management of PJI of the ankle. We evaluated the outcome, at two or more years post-operatively, in 34 patients with PJI of the ankle, identified from a cohort of 511 patients who had undergone total ankle replacement. Their median age was 62.1 years (53.3 to 68.2), and 20 patients were women. Infection was exogenous in 28 (82.4%) and haematogenous in six (17.6%); 19 (55.9%) were acute infections and 15 (44.1%) chronic. Staphylococci were the cause of 24 infections (70.6%). Surgery with retention of one or both components was undertaken in 21 patients (61.8%), both components were replaced in ten (29.4%), and arthrodesis was undertaken in three (8.8%). An infection-free outcome with satisfactory function of the ankle was obtained in 23 patients (67.6%). The best rate of cure followed the exchange of both components (9/10, 90%). In the 21 patients in whom one or both components were retained, four had a relapse of the same infecting organism and three had an infection with another organism. Hence the rate of cure was 66.7% (14 of 21). In these 21 patients, we compared the treatment given to an algorithm developed for the treatment of PJI of the knee and hip. In 17 (80.9%) patients, treatment was not according to the algorithm. Most (11 of 17) had only one criterion against retention of one or both components. In all, ten of 11 patients with severe soft-tissue compromise as a single criterion had a relapse-free survival. We propose that the treatment concept for PJI of the ankle requires adaptation of the grading of quality of the soft tissues.

Cite this article: Bone Joint J 2014;96-B:772–7.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 10 | Pages 1367 - 1372
1 Oct 2011
Hintermann B Barg A Knupp M

We undertook a prospective study to analyse the outcome of 48 malunited pronation-external rotation fractures of the ankle in 48 patients (25 females and 23 males) with a mean age of 45 years (21 to 69), treated by realignment osteotomies. The interval between the injury and reconstruction was a mean of 20.2 months (3 to 98).

In all patients, valgus malalignment of the distal tibia and malunion of the fibula were corrected. In some patients, additional osteotomies were performed. Patients were reviewed regularly, and the mean follow-up was 7.1 years (2 to 15).

Good or excellent results were obtained in 42 patients (87.5%) with the benefit being maintained over time. Congruent ankles without a tilted talus (Takakura stage 0 and 1) were obtained in all but five cases. One patient required total ankle replacement.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 9 | Pages 1232 - 1239
1 Sep 2011
Stufkens SA van Bergen CJ Blankevoort L van Dijk CN Hintermann B Knupp M

It has been suggested that a supramalleolar osteotomy can return the load distribution in the ankle joint to normal. However, due to the lack of biomechanical data, this supposition remains empirical. The purpose of this biomechanical study was to determine the effect of simulated supramalleolar varus and valgus alignment on the tibiotalar joint pressure, in order to investigate its relationship to the development of osteoarthritis. We also wished to establish the rationale behind corrective osteotomy of the distal tibia.

We studied 17 cadaveric lower legs and quantified the changes in pressure and force transfer across the tibiotalar joint for various degrees of varus and valgus deformity in the supramalleolar area. We assumed that a supramalleolar osteotomy which created a varus deformity of the ankle would result in medial overload of the tibiotalar joint. Similarly, we thought that creating a supramalleolar valgus deformity would cause a shift in contact towards the lateral side of the tibiotalar joint. The opposite was observed. The restricting role of the fibula was revealed by carrying out an osteotomy directly above the syndesmosis. In end-stage ankle osteoarthritis with either a valgus or varus deformity, the role of the fibula should be appreciated and its effect addressed where appropriate.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 7 | Pages 921 - 927
1 Jul 2011
Barg A Henninger HB Hintermann B

The aim of this study was to identify the incidence of post-operative symptomatic deep-vein thrombosis (DVT), as well as the risk factors for and location of DVT, in 665 patients (701 ankles) who underwent primary total ankle replacement. All patients received low-molecular-weight heparin prophylaxis. A total of 26 patients (3.9%, 26 ankles) had a symptomatic DVT, diagnosed by experienced radiologists using colour Doppler ultrasound. Most thrombi (22 patients, 84.6%) were localised distally in the operated limb. Using a logistic multiple regression model we identified obesity, a previous venous thromboembolic event and the absence of full post-operative weight-bearing as independent risk factors for developing a symptomatic DVT.

The incidence of symptomatic DVT after total ankle replacement and use of low-molecular-weight heparin is comparable with that in patients undergoing total knee or hip replacement.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 12 | Pages 1659 - 1663
1 Dec 2010
Barg A Knupp M Hintermann B

The aim of this study was to compare the outcome of bilateral sequential total ankle replacement (TAR) with that of unilateral TAR. We reviewed 23 patients who had undergone sequential bilateral TAR under a single anaesthetic and 46 matched patients with a unilateral TAR. There were no significant pre-operative differences between the two groups in terms of age, gender, body mass index, American Society of Anaesthesiologists classification and aetiology of the osteoarthritis of the ankle. Clinical and radiological follow-up was carried out at four months, one and two years.

After four months, patients with simultaneous bilateral TAR reported a significantly higher mean pain score than those with a unilateral TAR. The mean American Orthopaedic Foot and Ankle Society hindfoot score and short-form 36 physical component summary score were better in the unilateral group. However, this difference disappeared at the one-and two-year follow-ups.

Bilateral sequential TAR under one anaesthetic can be offered to patients with bilateral severe ankle osteoarthritis. However, they should be informed of the long recovery period.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 11 | Pages 1540 - 1547
1 Nov 2010
Kim BS Knupp M Zwicky L Lee JW Hintermann B

We report the clinical and radiological outcome of total ankle replacement performed in conjunction with hindfoot fusion or in isolation. Between May 2003 and June 2008, 60 ankles were treated with total ankle replacement with either subtalar or triple fusion, and the results were compared with a control group of 288 ankles treated with total ankle replacement alone.

After the mean follow-up of 39.5 months (12 to 73), the ankles with hindfoot fusion showed significant improvement in the mean visual analogue score for pain (p < 0.001), the mean American Orthopaedic Foot and Ankle Society score (p < 0.001), and the mean of a modified version of this score (p < 0.001). The mean visual analogue pain score (p = 0.304) and mean modified American Orthopaedic Foot and Ankle Society score (p = 0.119) were not significantly different between the hindfoot fusion and the control groups. However, the hindfoot fusion group had a significantly lower mean range of movement (p = 0.009) and a higher rate of posterior focal osteolysis (p = 0.04). Both groups showed various complications (p = 0.131) and failure occurring at a similar rate (p = 0.685).

Subtalar or triple fusion is feasible and has minimal adverse effects on ankles treated with total ankle replacement up to midterm follow-up. The clinical outcome of total ankle replacement when combined with hindfoot fusion is comparable to that of ankle replacement alone. Thus, hindfoot fusion should be performed in conjunction with total ankle replacement when indicated.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_IV | Pages 587 - 587
1 Oct 2010
Knupp M Bollinger M Hintermann B Schuh R Stufkens S
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Introduction: Recent studies suggest that preservation of the calcaneocuboidal joint and a single medial approach may lead to equally good results as a conventional triple arthrodesis for painful malalignment or arthritis of the hindfoot. The theoretical advantage of a single medial approach for subtalar and talonavicular fusion is a lower risk for postoperative wound healing problems. The aim of our study was to assess the capability of the modified triple arthrodesis to correct hindfoot malalignment.

Methods: We retrospectively measured radiological parameters in 36 consecutive feet in 34 patients who underwent a modified triple arthrodesis. All operations were done with a single medial incision using rigid internal fixation with screws. Radiological evaluation was done at a mean of 15 months (range 6 to 34) postoperatively.

Results: The following angles showed a significant (p< 0.001) improvement: the talonavicular coverage from 23° (range,−51 to 51°) to 10° (range, −13 to 32°), the dorsoplantar talar-first metatarsal angle from 18° (range, −19 to 76°) to 9° (range, −11 to 28°), the lateral talo-calcaneal angle from 38° (range, 14 to 57°) to 28° (range, 12 to 44°), and the lateral talar-first metatarsal angle from −15° (range, −51 to 23°) to −4°(range, −18 to 22°). We encountered neither primary wound healing problems, nor bony nonunion.

Conclusions: In our study all radiological parameters improved postoperatively. We therefore believe that this is a safe and effective technique in the management of hindfoot deformity with predictable outcome even in patients with severe malalignment.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_IV | Pages 586 - 586
1 Oct 2010
Horisberger M Hintermann B Valderrabano V
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Background: While several studies in the last years tried to identify clinical limitations of patients suffering from end-stage ankle osteoarthritis (OA), very few attempted to assess foot and ankle function in a more objective biomechanical way, especially using dynamic pedobarography. The aim of the study was therefore to explore plantar pressure distribution characteristics in a large cohort of posttraumatic end-stage ankle OA.

Method: 120 patients (female, 54; male, 66; 120 cases) suffering from posttraumatic end-stage ankle OA were included. The clinical examination consisted of assessment of the AOFAS hindfoot score, a pain score, the range of motion (ROM) for ankle dorsiflexion and plantar flexion, and the body mass index (BMI, kg/m2). Radiological parameters included the radiological tibiotalar alignment and the radiological ankle OA grading. Plantar pressure distribution parameters were assessed using dynamic pedobarography.

Results: Intra-individual comparison between the affected and the opposite, asymptomatic ankle revealed significant differences for several parameters: maximum pressure force and contact area were decreased in the whole OA foot, such was maximum peak pressure in the hindfoot and toes area. No correlations could be found between clinical parameters, such as AOFAS hindfoot score, VAS for pain, and ROM, and the pedobarographic data. However, there was a positive correlation between dorsiflexion and the pedobarographic parameters for the hindfoot area.

Conclusion: In conclusion, posttraumatic end-stage ankle OA leads to significant alterations in plantar pressure distribution. These might be interpreted as an attempt of the patient to reduce the load on the painful ankle. Other explanations might be bony deformity and ankle malalignment as a consequence of either the initial trauma or of the degenerative process itself, pain related disuse atrophy of surrounding muscles, and scarred soft tissue.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 315 - 315
1 May 2010
Schneiderbauer M Trampuz A Hintermann B
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Background: The diagnosis of implant-associated infections is difficult due to organisms attached to surfaces as biofilms. We hypothesize that diagnosis can be improved by removing biofilm microorganisms from implant surface by sonication, followed by Gram stain, culture and calorimetric detection in sonication fluid.

Methods: We prospectively included adult patients from May 2005 until December 2006 from whom an orthopedic implant (joint prosthesis or internal fixation device) was removed for any reason. Removed implants were vortexed and sonicated in solid containers 5 min at 40 kHz in 100 to 400 ml Ringer’s solution. The resulting sonicate was plated and incubated on aerobic and anaerobic blood agar and aliquots were in parallel incubated at 37°C for 3 days in an isothermal calorimeter TAM III (TA Instruments, New Castle, DE). Gram stain was performed on sonicates centrifuged at 5000 g for 10 min. Definitive infection diagnosis was of the implant was defined if purulence surrounding the implant, or growth of the same microorganism in ≥2 synovial fluid or intraoperative tissue specimens, or acute inflammation in histopathology, or a sinus tract was present. Sonicate culture was defined positive if > 10 cfu (colony forming units) grew/ml sonicate. Calorimetry was defined positive if heat flow rate increased ≥10 μW above baseline (detection limit ~0.3 μW).

Results: 846 implants (367 joint prostheses and 479 internal fixation devices) were studied, of which 171 (20%) were infected and 675 (80%) were aseptic cases. The sensitivity of intraoperative tissue cultures was 74%, of sonicate culture 89%, of sonicate Gram stain 51%, of sonicate calorimetry 96%. The specificity of all specimens was ≥95%.

Conclusion: Sonicate culture and calorimetry were more sensitive than intraoperative tissue cultures for diagnosing implant infections. With Gram stain of centrifuged sonicate, infection was diagnosed in > 50% cases. Sonicate culture and calorimetry may replace the current approach using multiple intraoperative periprosthetic tissue specimens, whenever the implant or part of it is removed.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 339 - 339
1 May 2010
Valderrabano V Ebneter L Leumann A von Tscharner V Hintermann B
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Introduction: Ankle sprains are among the most common injuries in sports and recreational activities. 10 to 40% of the acute ankle sprains lead to chronic ankle instability (CAI), which can be divided into its mechanical and its functional division. The clinical-orthopaedic diagnosis of mechanical ankle instability (MAI) has been well established, whereas the etiology of the functional ankle instability (FAI) is still not objectively allocatable. The aim of this study was to identify neuromuscular patterns in lower leg muscles to objectively describe the FAI.

Methods: 15 patients suffering from unilateral CAI (mean age, 35.5 years) since 2.4 years (1–9 years) were examined. The patients were evaluated etiologically and clinically (VAS pain score, AOFAS Ankle Score, calf circumference, and SF-36). Electromyographic (EMG) measurements of surface EMG with determination of mean EMG frequency and intensity by wavelet transformation were taken synchronously with dynamic stabilometry measurements. Four lower leg muscles were detected: tibialis anterior (TA), gastrocnemius medialis (GM), soleus (SO), and peroneus longus (PL) muscle. 15 healthy subjects were tested identically.

Results: Patients showed higher stability indices, higher VAS score, and lower AOFAS Ankle Score.

The mean EMG frequency was significantly lower for the PL (pathologic leg, 138.3 Hz; normal leg, 158.3 Hz, p< 0.001). Lower mean EMG intensity was found in the pathologic PL and GM. The mean EMG frequency of the TA was lower in the patient group, its intensity higher.

Discusssion and conclusion: Patients suffering CAI demonstrate weakened stability and impaired life quality. Neuromuscular patterns of the GM, PL and TA lead evidently to an objective etiology of the functional ankle instability. EMG patterns of four lower leg muscles indicate chronic changes in muscle morphology, such as degradation of type-II muscle fibres or modified velocity of motor unit action potentials. Accurate prevention and rehabilitation may compensate a MAI with a sufficient functional potential of lower leg muscles. This may also avoid operative treatment of MAI. The present study evidences the etiology of the FAI with objective parameters and indicates chronic changes in muscle morphology within CAI-Patients.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 21 - 21
1 Mar 2010
Valderrabano V Ebneter L Leumann A von Tscharner V Hintermann B
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Purpose: Ankle sprains are among the most common injuries in sports and recreational activities. 10 to 40% of the acute ankle sprains lead to chronic ankle instability (CAI), which can be divided into its mechanical and its functional division. The clinical-orthopaedic diagnosis of mechanical ankle instability (MAI) has been well established, whereas the etiology of the functional ankle instability (FAI) is still not objectively allocatable. The aim of this study was to identify neuromuscular patterns in lower leg muscles to objectively describe the FAI.

Method: 15 patients suffering from unilateral CAI (mean age, 35.5 years) since 2.4 years (1–9 years) were examined. The patients were evaluated etiologically and clinically (VAS pain score, AOFAS Ankle Score, calf circumference, and SF-36). Electromyographic (EMG) measurements of surface EMG with determination of mean EMG frequency and intensity by wavelet transformation were taken synchronously with dynamic stabilometry measurements. Four lower leg muscles were detected: tibialis anterior (TA), gastrocnemius medialis (GM), soleus (SO), and peroneus longus (PL) muscle. 15 healthy subjects were tested identically.

Results: Patients showed higher stability indices, higher VAS score, and lower AOFAS Ankle Score. The mean EMG frequency was significantly lower for the PL (pathologic leg, 138.3 Hz; normal leg, 158.3 Hz, p< 0.001). Lower mean EMG intensity was found in the pathologic PL and GM. The mean EMG frequency of the TA was lower in the patient group, its intensity higher.

Conclusion: Patients suffering CAI demonstrate weakened stability and impaired life quality. Neuromuscular patterns of the GM, PL and TA lead evidently to an objective etiology of the functional ankle instability. EMG patterns of four lower leg muscles indicate chronic changes in muscle morphology, such as degradation of type-II muscle fibres or modified velocity of motor unit action potentials. Accurate prevention and rehabilitation may compensate a MAI with a sufficient functional potential of lower leg muscles. This may also avoid operative treatment of MAI. The present study evidences the etiology of the FAI with objective parameters and indicates chronic changes in muscle morphology within CAI-Patients.


History and Background: The HINTEGRA® Total Ankle Prosthesis was designed in 2000 by Dr. B. Hintermann (Basel, Switzerland); Dr. G. Dereymaeker (Pellenberg, Belgium); Dr. R. Viladot (Barcelona/Spain); and Dr. P. Diebold (Maxeville, France), and is manufactured by Newdeal SA in Lyon, France.

Design Features: The HINTEGRA® Total Ankle Prosthesis is a non-constrained, three-component system that provides inversion/eversion stability. Axial rotation and normal flexion/extension mobility are provided by a mobile bearing element. Limits of motion are dependent on natural soft-tissue constraints: no mechanical prosthetic motion constraints are imposed for any ankle movement with this device. The HINTEGRA® ankle uses all available bone surface for support. The anatomically shaped, flat tibial and talar components essentially resurface the tibia and talar dome, respectively, and wings hemiprosthetically replace degenerate medial and lateral facets (a potential source of pain and impingement). No more than 2 to 3 mm of bone removal on each side of the joint is necessary to insert the tibial and talar components. On the tibial side, most importantly, the bony architecture remains intact, and in particular, the anterior cortex is preserved. Perfect apposition with the hard subchondral bone is achieved by the flat resection of the bone and the flat surface of the component. Primary stability for coronal plane motion is provided by two screws inserted into the anterior shield, in the upper part of oval holes so that the settling process of the component is not hindered by axial loading. On the talar side, additional anterior support is provided by a shield, and pressfit is provided by the slightly curved wings. Two pegs facilitate the insertion of the talar component and provide additional stability, particularly against anterior-posterior translation. Another advantage of this concept is the instrumentation that allows reliable implantation of components.

Technique: The prosthesis is implanted through an anterior approach. In the case of malalignment, ligamentous instability, and concomitant osteoarthrosis of the distal joints, additional surgeries are considered before prosthetic implantation.

Complications: In the beginning, a major concern was the positioning of the talar component, which tended to slide too posteriorly while impacting and press fitting. With the addition of two talar pegs, the current design may resist such translational forces during press fitting.

There is evidence that positioning of the talar component too posteriorly may cause pain and limit dorsiflexion of the foot (probably because the posterior aspects of the deltoid ligament are over-tensioned), thereby the intrinsic forces are also increased which may cause unacceptable high shear forces at the bone-implant interface and/or component instability. In all but one of the seven revised talar components (out of the author’s first 400 cases), the component was positioned too posteriorly.

There is a potential risk for dislocation of the meniscal component either laterally or medially as long as no appropriate alignment and/or ligament balancing have been achieved during surgery. The author encountered this problem only in two of the first twenty cases; thereafter, no such complications occurred probably because of better understanding alignment and balancing the ankle.

A potential concern in uncemented resurfacing prostheses is the use of screws that may create stress shielding. The HINTEGRA® ankle, however, uses oval holes on the tibial side so that some settling of the component during osteointegration is possible. As screw fixation is located eccentric to the load transfer area, the potential for stress shielding is in addition minimized.

Salvage of Complications: Special revision implants are available for salvage of failed components. On tibial side, components with a thicker plateau may serve to replace loosed bone stock and to get firm bony support more proximally, thereby preserving the original joint line (that means, the ankle ligaments are supposed to be properly used for stabilizing and guidance of the joint). On talar side, components with a flat undersurface allow flat resection of the talus, thus providing a wide area of bone support to the revision component.

Results: Between 05/2000 and 12/2006, 340 primary TAA were performed in 322 patients (females, 165; males, 157, age 57.3 ± 13.4 years). Underlying diagnosis was posttraumatic osteoarthritis in 272 ankles, primary osteoarthritis in 26 ankles and inflammatory arthritis in 42 ankles. All patients were clinically and radiologically assessed after 6.2 (1.1–7.5) years, and survivorship analysis was calculated. Revision of a metallic implant or conversion into ankle arthrodesis was taken as the endpoint.

The AOFAS Hindfoot Score improved from 42.1 (14–61) points preoperatively to 78.6 (44–100) points at follow-up. 205 ankles (60.5%) were completely pain free. The average range of motion was clinically 32.2° (range, 15° to 55°), and under fluoroscopy (that is, true ankle motion) 30.4° (range, 7° to 62°). Four ankles were revised to TAA (component loosening, 3; pain, 1), and 2 ankles (component loosening and recurrent misalignment, 1; pain, 1) were revised to ankle arthrodesis. Overall survivorship at 6 years was 98.2%, being 97.9% for the talar component and 98.8% for the tibial component.

Four ankles (1.2%) were successfully revised, and the obtained result at latest follow-up did not differ from those ankles without complications. Whereas, 2 ankles (0.6%) were revised to ankle arthrodesis.

In another series of 37 patients (37 ankles: STAR, 26 ankles; HINTEGRA, 3 ankles; AGILITY, 3 ankles, Büchel-Pappas, 2 ankles; MOBILITY, 2 ankles; SALTO, 1 ankle) with failed total ankle arthroplasty, revision arthroplasty was performed with the HINTEGRA® ankle. All but one surgery were successful. At a mean follow-up of 3.6 (1.2–6.4) years, 29 patients (78.4%) were satisfied with the obtained result. The AOFAS Hindfoot Score improved from 39.2 (23–58) points pre-operatively to 72.8 (54–95) points. All but on implants were radiographically stable; in one case, the tibial component showed, at one year, still a radioluscency which may be considered as loosening. As the patient is completely pain free, no revision surgery was done.

In another series of 29 patients (30 ankles), a painful ankle fusion was taken down and ankle arthroplasty was performed with the HINTEGRA® ankle. All surgeries were successful. At a mean follow-up of 3.4 (2–7.6) years, 24 patients (80%) were satisfied with the obtained result. The AOFAS Hindfoot Score improved from 34.1 (18–47) points preoperatively to 69.4 (48–90) points. The obtained motion for dorsi-/plantar flexion was clinically 23.5° (10°–40°) [52.6% of contra lateral ankle), and radiographically (“true ankle motion”) 24.5°(8°–24°) [54.4% of contra lateral ankle].

The author’s overall experience: more than 750 replacements with the HINTEGRA® ankle in the last 8 years. The learning curve was rather long as some adjustments had to be performed, and there was need of some time to understand “ligament balancing” in ankle replacement in more detail. However, since then, an extremely high satisfaction rate was obtained, and most patients are doing very well. The revision rate has also turned down to < 2% despite, with increased experience, more complex cases may have been considered for ankle replacement.

Conclusion: Obviously, TAA using a current anatomic design of 3-component prosthesis (HINTEGRA) have evolved to a safe procedure with reliable results at mid- to long-term. These encouraging results support our belief that TAA has become a viable alternative to ankle arthrodesis even for younger patients and more difficult conditions, as often the case in posttraumatic osteoarthritis.


The Journal of Bone & Joint Surgery British Volume
Vol. 91-B, Issue 12 | Pages 1607 - 1611
1 Dec 2009
Stufkens SAS Knupp M Lampert C van Dijk CN Hintermann B

We have compared the results at a mean follow-up of 13 years (11 to 14) of two groups of supination-external rotation type-4 fractures of the ankle, in one of which there was a fracture of the medial malleolus and in the other the medial deltoid ligament had been partially or completely ruptured.

Of 66 patients treated operatively between 1993 and 1997, 36 were available for follow-up. Arthroscopy had been performed in all patients pre-operatively to assess the extent of the intra-articular lesions. The American Orthopaedic Foot and Ankle Society hind-foot score was used for clinical evaluation and showed a significant difference in both the total and the functional scores (p < 0.05), but not in those for pain or alignment, in favour of the group with a damaged deltoid ligament (p < 0.05). The only significant difference between the groups on the short-form 36 quality-of-life score was for bodily pain, again in favour of the group with a damaged deltoid ligament. There was no significant difference between the groups in the subjective visual analogue scores or in the modified Kannus radiological score.

Arthroscopically, there was a significant difference with an increased risk of loose bodies in the group with an intact deltoid ligament (p < 0.005), although there was no significant increased risk of deep cartilage lesions in the two groups.

At a mean follow-up of 13 years after operative treatment of a supination-external rotation type-4 ankle fracture patients with partial or complete rupture of the medial deltoid ligament tended to have a better result than those with a medial malleolar fracture.


The Journal of Bone & Joint Surgery British Volume
Vol. 91-B, Issue 9 | Pages 1191 - 1196
1 Sep 2009
Pagenstert GI Barg A Leumann AG Rasch H Müller-Brand J Hintermann B Valderrabano V

The precise localisation of osteoarthritic changes is crucial for selective surgical treatment. Single photon-emission CT-CT (SPECT-CT) combines both morphological and biological information. We hypothesised that SPECT-CT increased the intra- and interobserver reliability to localise increased uptake compared with traditional evaluation of CT and bone scanning together. We evaluated 20 consecutive patients with pain of uncertain origin in the foot and ankle by radiography and SPECT-CT, available as fused SPECT-CT, and by separate bone scanning and CT. Five observers assessed the presence or absence of arthritis. The images were blinded and randomly ordered. They were evaluated twice at an interval of six weeks. Kappa and multirater kappa values were calculated.

The mean intraobserver reliability for SPECT-CT was excellent (κ = 0.86; 95% CI 0.81 to 0.88) and significantly higher than that for CT and bone scanning together. SPECT-CT had significantly higher interobserver agreement, especially when evaluating the naviculocuneiform and tarsometatarsal joints.

SPECT-CT is useful in localising active arthritis especially in areas where the number and configuration of joints are complex.


The Journal of Bone & Joint Surgery British Volume
Vol. 91-B, Issue 5 | Pages 612 - 615
1 May 2009
Knupp M Schuh R Stufkens SAS Bolliger L Hintermann B

We describe a retrospective review of the clinical and radiological parameters of 32 feet in 30 patients (10 men and 20 women) who underwent correction for malalignment of the hindfoot with a modified double arthrodesis through a medial approach. The mean follow-up was 21 months (13 to 37). Fusion was achieved in all feet at a mean of 13 weeks (6 to 30). Apart from the calcaneal pitch angle, all angular measurements improved significantly after surgery. Primary wound healing occurred without complications.

The isolated medial approach to the subtalar and talonavicular joints allows good visualisation which facilitated the reduction and positioning of the joints. It was also associated with fewer problems with wound healing than the standard lateral approach.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_I | Pages 21 - 21
1 Mar 2006
Knupp M Magerkurth O Ledermann H Hintermann B
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Introduction: Realigning the foot and good ligament balancing have been recognized to be the mainstay for successful reconstruction of complex hindfoot disorders and deformities. This is particularly true for posttraumatic conditions, where deformities and scarring might be the underlying cause of foot dysfunction. For surgical reconstruction, i.e. osteotomies, arthrodeses and total ankle replacement, references are needed for restoration of the anatomy and the function. Most surprisingly to date no data is available regarding dimensions on standard X-rays of the hindfoot. The purpose of this prospective study therefore was 1) to define relevant and reproducible measures on lateral hindfoot X-rays and 2) to assess their reliability.

Methods: 100 lateral view X-rays were taken. Dimensions assessed were the talar area covered by the tibia, the angle of the distal tibial joint plane to the tibial axis (tilt), the width of the tibia on the joint level, the height of the talus, the joint radius of the ankle joint and the offset of the centre of rotation from the tibial axis.

Results: The tibial coverage of the talus was 88.1 degrees (SD = 0.36), the angle of the distal tibial joint plane to the tibial axis (tilt) was 83 degrees (SD 3.6), the width of the distal tibia 33.6 mm (SD = 2.4), the radius of the ankle joint 18.6 mm (SD = 4.0) with an anterior offset of the centre of rotation of 1.7 mm and the height of the talus was 28.2 mm (SD = 2.1).

Conclusions: In case of symptomatic deformity any reconstruction, i.e. correcting osteotomies, ligament reconstruction, arthrodeses or arthroplasty, should aim to correct the foot in a physiological way; respecting the original dimensions of the hindfoot to achieve maximal benefit. Anterior-posterior translation of the talus may be a source of pain, restriction of motion and a cause of degenerative joint disease because of eccentric joint loading. This is also true for the height of the talus, which may have a significant impact on the hindfoot physiology. To achieve good biomechanical function, the positioning of the talus in relation to the tibia needs to be planned carefully prior to surgery. Poor coverage of the talus by the tibia and too much tilt of the distal tibia lead to higher joint forces and may be the cause of instability. Surgical procedures may fail if this is not recognized preoperatively. Several easily accessible measures on X-rays were found to be reliable to describe the hind-foot, as only small variation was found on the evaluated X-rays. If reconstruction of the hindfoot is required, care should be taken to identify the physiological joint geometry.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_I | Pages 24 - 25
1 Mar 2006
Frank O Horisberger M Hintermann B
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Introduction: Posttraumatic osteoarthritis of the ankle joint usually occurs secondary to an intraarticular fracture of the weight bearing ankle joint. The question whether also recurrent ankle sprain and /or chronic instability alone can cause this entity, is, however, still a question to debate. The aim of this retrospective study was, therefore, to analyse the history and findings of a consecutive series of patients that were treated for post-traumatic end-stage osteoarthrosis of the ankle.

Methods: The complete database (including physical exam, standard radiographs, patient questionnaire and AOFAS hindfoot score) of all patients was analysed.

Results: Out of 268 patients (females, 135 patients; males, 133) 221 (82.5%) had had a fracture (Fx) and 47 (17.5%) suffered from chronic ankle instability with recurrent sprains (but did not have a fracture). The latter group could be subdivided into 29 (10.8%) patients with recurrent sprains (RS) and 10 (6.7%) patients with only a single sprain (SS). The mean (range) delay between primary trauma and surgical treatment for endstage osteoarthritis was 21.1 (1–58) months for Fx, 37.07 (1–61) months for RS and 22.5 (5–48) months for SS.

Conclusion: Obviously, not only fractures, but also severe sprains and /or chronic instability play an important role as a cause of end stage osteaorthrosis of the ankle joint. The obtained results suggest that a single severe sprain (dislocation) can cause similar articular damages to an intraarticular fracture, as the time to develop osteoarthrosis does not differ. This is in contrast to the current opinion that ankle sprain, in most instances, does not result in symptomatic articular degeneration.


The Journal of Bone & Joint Surgery British Volume
Vol. 82-B, Issue 8 | Pages 1107 - 1112
1 Nov 2000
Hintermann B Trouillier HH Schäfer D

In 42 elderly patients, 33 women and nine men with a mean age of 72 years, we treated displaced fractures of the proximal humerus (34 three-part, 8 four-part) using a blade plate and a standard deltopectoral approach. Functional treatment was started immediately after surgery. We reviewed 41 patients at one year and 38 at final follow-up at 3.4 years (2.4 to 4.5).

At the final review, all the fractures had healed. The clinical results were graded as excellent in 13 patients, good in 17, fair in seven, and poor in one. The median Constant score was 73 ± 18. Avascular necrosis of the humeral head occurred in two patients (5%).

We conclude that rigid fixation of displaced fractures of the proximal humerus with a blade plate in the elderly patient provides sufficient primary stability to allow early functional treatment. The incidence of avascular necrosis and nonunion was low. Restoration of the anatomy and biomechanics may contribute to a good functional outcome when compared with alternative methods of fixation or conservative treatment. Regardless of the age of the patients, we advocate primary open reduction and rigid internal fixation of three- and four-part fractures of the proximal humerus.


The Journal of Bone & Joint Surgery British Volume
Vol. 82-B, Issue 3 | Pages 345 - 351
1 Apr 2000
Hintermann B Regazzoni P Lampert C Stutz G Gächter A

We have evaluated prospectively the arthroscopic findings in acute fractures of the ankle in 288 consecutive patients (148 men and 140 women) with a mean age of 45.6 years. According to the AO-Danis-Weber classification there were 14 type-A fractures, 198 type B and 76 type C.

Lesions of the cartilage were found in 228 ankles (79.2%), more often on the talus (69.4%) than on the distal tibia (45.8%), the fibula (45.1%), or the medial malleolus (41.3%). There were more lesions in men than in women and in general they were more severe in men (p < 0.05). They also tended to be worse in patients under 30 years and in those over 60 years of age. The frequency and severity of the lesions increased from type-B to type-C fractures (p < 0.05). Within each type of fracture the lesions increased from subgroups 1 to 3 (p < 0.05). The anterior tibiofibular ligament was injured with increased frequency from type-B.1 to type-C.3 fractures (p < 0.05), but it was not torn in all cases. While lateral ligamentous injuries were seen more often in type-B than in type-C fractures (p < 0.05), no difference was noted in the frequency of deltoid ligamentous lesions.

Our findings show that arthroscopy is useful in identifying associated intra-articular lesions in acute fractures of the ankle.