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Scientific Articles:
Beat Hintermann, Alexej Barg, Markus Knupp, and Victor Valderrabano
Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty
J Bone Joint Surg Am 2009; 91: 850-858 [Abstract] [Full text] [PDF]
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[Read Letter to the Editor] Dr. Hintermann and colleagues respond to Dr. Kini
Beat Hintermann, MD, Alexej Barg, MD; Markus Knupp, MD; Victor Valderrabano, MD, PhD   (30 April 2009)
[Read Letter to the Editor] Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty
Sunil Gurpur Kini, MBBS, MS(Ortho), DNB(Ortho), MNAMS(Ortho)   (30 April 2009)

Dr. Hintermann and colleagues respond to Dr. Kini 30 April 2009
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Beat Hintermann, MD,
Associate Professor, Chairman
Clinic of Orthopaedic Surgery, Liestal, Switzerland,
Alexej Barg, MD; Markus Knupp, MD; Victor Valderrabano, MD, PhD

Send letter to journal:
Re: Dr. Hintermann and colleagues respond to Dr. Kini

beat.hintermann{at}ksli.ch Beat Hintermann, MD, et al.

We thank Dr. Kini for his interest and comments on our study and we are grateful for the opportunity to make the following comments:

At the latest follow up, any persisting pain laterally was localized to periarticular soft tissues. This finding can be best explained by the fact that most of the patients included in this study had an average of 3.3 previous operations (range, zero to nine procedures). To exclude the possibility of subtalar arthritis or arthritis in other adjacent joints as the cause of pain, we recommend performing single photon emission computed tomography (SPECT-CT) (1). In seven patients, pain was mainly localized in medial aspect of the ankle at the latest follow-up. The origin of this pain was irritation of periarticular soft tissues and not osseous impingement at the medial side of the ankle in patients in whom the mechanical axis had been restored . It is imperative that the tibial component and the heel are properly aligned to the mechanical axis of leg. If the tibial component is implanted in a varus position, and/or the heel is in valgus, osseous impingement in the medial gutter was seen to occur.

2) In this patient group, all persons were allowed full weight bearing in the cast. However, in some patients, we recommend non-weight bearing for 8 weeks postoperatively. During the first clinical and radiographic follow up at 6 weeks postoperatively, we have measured the range of motion to be slightly less in patients who were non weight bearing when compared to those patients who were fully weight bearing; however, the difference was not statistically significant. At the next follow-up (4 months postoperatively), we did not detect any difference in range of motion between these patient groups.

Newer gait analysis studies show that a nearly normal gait pattern is present in terms of joint kinematics of the knee, ankle, and foot after uneventful mobile-bearing total ankle replacement (2). Dr.Kini stated in his letter that if 10º dorsiflexion is not obtained during the the mid-portion of stance phase, the gait will be similar to what is observed following ankle arthrodesis (3). However, we believe that the ankle mobility gained after this arthroplasty, even in cases with dorsiflexion less than 10º, can decrease the stress forces in the adjacent joint which may slow down the development of osteoarthritis as reported in patients who underwent ankle fusion (4,5).

3) Indeed, malleolar fracture has been reported as a common intraoperative complication with an incidence up to 10% (6,7). In this study, we observed five fractures of the malleoli (including the medial malleolus in three ankles, the lateral malleolus in one ankle, and a bimalleolar fracture in one ankle). Therefore, we now use prophylactic pinning in cases where the malleoli seem to be at risk of fracture.

References

1. Knupp M, Pagenstert GI, Barg A, Bolliger L, Easley ME, Hintermann B. SPECT-CT compared with conventional imaging modalities for the assessment of the varus and valgus malaligned hindfoot. J Orthop Res. 2009 (accepted for publication).

2. Doets HC, van Middelkoop M, Houdijk H, Nelissen RG, Veeger HE. Gait analysis after successful mobile bearing total ankle replacement. Foot Ankle Int. 2007;28:313-22.

3. Conti SF. Gait before and after total ankle arthroplasty with a comparison to arthrodesis. In: International Federation of Foot and Ankle Societies, Triennial Scientific Meeting; 2002; San Francisco, CA.

4. Coester LM, Saltzman CL, Leupold J, Pontarelli W. Long-term results following ankle arthrodesis for post-traumatic arthritis. J Bone Joint Surg Am. 2001;83:219-28.

5. Mazur JM, Schwartz E, Simon SR. Ankle arthrodesis. Long-term follow-up with gait analysis. J Bone Joint Surg Am. 1979;61:964-75.

6. Lee KB, Cho SG, Hur CI, Yoon TR. Perioperative complications of HINTEGRA total ankle replacement: our initial 50 cases. Foot Ankle Int. 2008;29:978-84.

7. Wood PL, Deakin S. Total ankle replacement. The results in 200 ankles. J Bone Joint Surg Br. 2003;85:334-41.
Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty 30 April 2009
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Sunil Gurpur Kini, MBBS, MS(Ortho), DNB(Ortho), MNAMS(Ortho),
Registrar, Orthopaedics
Guru Teg Bahadur Hospital, University College of Medical Sciences, Delhi, India

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Re: Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty

drsunilkini{at}gmail.com Sunil Gurpur Kini, MBBS, MS(Ortho), DNB(Ortho), MNAMS(Ortho)

To the Editor:

I read with interest the article by Hintermann et al. (1) and would like to offer the following comments and ask some questions of the authors.

A major concern regarding ankle arthroplasty continues to be the high rate of revision surgeries. SooHoo et al., in a study of 480 ankle replacements performed during a ten-year study period, reported rates of major revision surgery after ankle replacement of 9% at one year and 23% at five years (2).

Alhough the unconstrained mobile bearing ankle prosthesis has yielded good results in the short term,long term results will need to be evaluated with respect to revision rates, especially for polyethylene wear, aseptic loosening, and loss of axial alignment.

I would like to have the authors opinion on the following queries:

1) The authors reported persistent pain after arthroplasty in 24 of 29 ankles. Did they localize the origin of pain? If the cause of pain was subtalar arthritis secondary to arthrodesis, arthroplasty would not have addressed this pathology.

2) Did the authors notice any difference in range of motion in non weight bearing and weight bearing modes? Whatever range of ankle motion is provided by the implant is not necessarily utilized during steady state walking. If 10° dorsiflexion is not obtained during the mid-portion of stance phase, then, from a functional perspective, the gait adopted is similar to what is observed following an ankle arthrodesis.

3) Keeping in mind the high rate of intraoperative malleolar fractures reported in literature (4), do the authors recommend prophylactic pinning in all cases?

4) Was medial ankle pain/impingement a prominent finding in postoperative follow-up?

The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of his immediate family, is affiliated or associated.

References

1. Hintermann B, Barg A, Knupp M, Valderrabano, V. Conversion of painful ankle arthrodesis to total ankle artrhoplasty. J Bone Joint Surg Am. 2009;91:850-8.

2. SooHoo NF, Zingmond DS, Ko CY. Comparison of reoperation rates following ankle arthrodesis and total ankle arthroplasty. J Bone Joint Surg Am. 2007;89:2143-9.

3. Conti SF. Gait before and after total ankle arthroplasty with a comparison to arthrodesis. In: International Federation of Foot and Ankle Societies Triennial Scientific Meeting. 2002; San Francisco, CA.

4. Wood PL, Deakin S. Total ankle replacement. The results in 200 ankles. J Bone Joint Surg Br. 2003;85:334-41.