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Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results
Journal of Orthopaedic Science xxx (2018) 1e6
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Original Article
Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results Kota Watanabe a, *, Atsushi Teramoto b, Takuma Kobayashi b, Yuzuru Sakakibara b, Hiroaki Shoji b, Shinichiro Okimura b, Satoshi Nuka c, Toshihiko Yamashita b a b c
Department of Physical Therapy, Sapporo Medical University School of Health Sciences, South-1, West-17, Chuoku, Sapporo, Hokkaido, 060-8556, Japan Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1, West-16, Chuoku, Sapporo, Hokkaido, 060-8543, Japan Department of Orthopaedic Surgery, Hakodate Goryokaku Hospital, 38-3, Goryokakuchou, Hakodate, Hokkaido, 0400001, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 2 February 2017 Received in revised form 23 April 2018 Accepted 29 August 2018 Available online xxx
Background: Low tibial osteotomy is an effective joint-preserving surgery for ankle arthritis. However, poor postoperative wound healing, infection, and delayed or non-union of bones remain significant concerns. We describe a modified distal tibial oblique osteotomy procedure and report preliminary results for varus ankle arthritis. Methods: The osteotomy path consisted of an oblique doglegged line from the lateral end of the distal tibia to a proximal point about one-third from the lateral edge and continuing along an arc defined by virtual coronal-plane rotation of the doglegged line to the medial edge. After osteotomy, the distal tibial fragment was rotated distally in the coronal plane for realignment while maintaining contact with the proximal tibia and the distal tibial fragment. The resulting wedge-shaped gap was filled with artificial bone blocks and tibial bone projecting medially from rotation. A locking plate was then applied for stabilization. We evaluated 7 ankles from 6 osteoarthritis patients both clinically and radiographically following this procedure. Results: Bone union was achieved within 3 months for all patients. The Japanese Society for Surgery of the Foot ankleehindfoot scale improved from a mean of 38.4 points preoperatively to 85.7 points at the latest follow-up. No wound healing problems, infections, or nerve disturbances were observed. Multiple radiographic parameters were also improved following the operation. Conclusions: This procedure maintains close bone contact for better postoperative union, obviates the need for iliac bone harvesting, and reduces tension on medial soft tissue. We believe these modifications are potential advantages for achieving stable results in patients with ankle osteoarthritis. © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
1. Introduction Supramalleolar low tibial osteotomy (LTO) is an effective operative procedure for the management of ankle arthritis with varus or valgus deformity. Indeed, open-wedge, closed-wedge, and intraarticular variants of LTO can correct biomechanical abnormalities like aberrant pressure distribution in the tibiotalar joint by realigning the deformity [1,2]. Early and mid-stage ankle osteoarthritis are generally accepted as indications for these procedures.
* Corresponding author. Department of Physical Therapy, Sapporo Medical University School of Health Sciences, South-1, West-17, Chuoku, Sapporo, Hokkaido, 060-8556, Japan. Fax: þ11 641 6026. E-mail address: [email protected] (K. Watanabe).
For instance, Tanaka et al. reported that LTO was indicated for varus-type stage 2 or stage 3a osteoarthritis (Table 1) [3]. Previous investigators reported clinically significant pain relief and functional improvement following these procedures [1,3e16]. Open-wedge LTO in particular has been widely used for varus ankle arthritis. In this procedure, the osteotomy line is parallel or slightly oblique to the distal tibial articular surface, with a medial point about 5 cm above the tip of the medial malleolus. In most cases, tibial osteotomy is combined with fibular osteotomy [3e7,15]. Teramoto et al. developed distal tibial oblique osteotomy (DTOO) and achieved good outcomes in stage 3b or 4 patients [8e10] In this procedure, the distal tibia is osteotomized obliquely toward the distal tibiofibular joint. The distal tibial fragment is spread until the lateral articular surface of the talus contacts the medial articular surface of the lateral malleolus. Iliac bone is then
https://doi.org/10.1016/j.jos.2018.08.020 0949-2658/© 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
2
K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6 Table 1 Classification of varus ankle osteoarthritis (from Takakura et al., 1995; Tanaka et al., 2006). Stage
Characteristics
1 2 3a 3b 4
No narrowing of the joint-space, but early sclerosis and formation of osteophytes Narrowing of the medial joint space Obliteration of the medial joint space with subchondral bone contact. The obliteration is limited to the medial malleolus Obliteration of the medial joint space with subchondral bone contact. The obliteration extends to the roof of the dome of the talus Obliteration of the whole joint space with complete bone contact
grafted into the spreading space and an Ilizarov external fixator or a locking plate is used to stabilize the osteotomy site. This DTOO operation can restore the congruence of the tibiotalar joint surface, improving both the alignment and stability of the ankle joint. Favorable outcomes have also been reported using similar tibial osteotomy designs [12e14]. While these realignment osteotomies can lead to good clinical outcomes, there are still risks of postoperative complications. Soft tissue is thin around the osteotomy site and over-tension of the soft tissue may occur following realignment or internal fixation with implants. Indeed, several complications have been reported following supramalleolar osteotomies for ankle osteoarthritis, including wound healing problems, infection, delayed/non-union of bone, and painful hardware [1]. Another potential concern is morbidity associated with harvesting iliac crest for the bone graft. We have also observed non-union cases following LTO and complications at the iliac crest bone harvesting site. To improve outcome and reduce complications, we have developed a modified DTOO procedure. The purposes of this study are to introduce our procedure and report results for varus ankle arthritis. 2. Patients and methods This study included 7 ankles of 6 patients (6 female, 1 male) with ankle osteoarthritis. Approval for this study was granted by our institutional review board (IRB) and informed consent was obtained from each patient. Radiographic ankle osteoarthritis stage according to the Takakura-Tanaka classification ranged from 2 to 3b [3,4]. All patients had suffered from their affected ankles for more than one year and were treated conservatively for at least 6 months. Patient demographic data are shown in Table 2. Operative procedure: The procedure developed is modified from ankle mortise reconstruction, which has been reported as DTOO [8e10,13] or distal tibial rotational osteotomy (DTRO) [9,11]. The purpose of DTOO is to improve the alignment and stability of the ankle joint [9e11]. During the operation multidirectional stress tests are performed to confirm ankle joint stability by using an image intensifier. Modification of this procedure was devised to achieve the following: (1) Maintained contact of the distal and proximal tibial bones after osteotomy, (2) No bone harvesting from other sites (iliac bone), and (3) Usage of an internal fixation (plate) for stabilization. The planned osteotomy path combined a doglegged line
from the lateral edge of the distal tibia and an arc defined by virtual coronal-plane rotation of this line (Fig. 1). The center of this virtual circle was set at the lateral edge of the distal tibia. The radius of this circle was the horizontal distance from the circle center to the medial tibial surface. The osteotomy arc was designed on the virtual circle with the lateral tibial cortex spared. Basically we set the width of the osteotomy arc to two-third of the transverse diameter of the tibia to avoid fracture. The oblique osteotomy line from the center of the virtual circle was an equiangular bisector of the distal tibial lateral portion (about 45 from the articular surface of the distal tibia). This line was connected with the vertical line from the lateral end of the osteotomy arc. The patient lay on the operative table in a supine position with a tourniquet. A Kirschner wire was inserted from the lateral fibula percutaneously to the tibia under fluoroscopic guidance to stabilize the distal tibiofibular syndesmosis temporarily and avoid displacement when the distal tibial fragment was rotated in the coronal plan after osteotomy. It was helpful to put a short Kirschner wire at the center of the virtual circle to identify this point for osteotomy (Fig. 2C). An L-shaped incision was used to expose medial and anterior aspects of the distal tibia, and the periosteum was peeled off along the osteotomy path. Multiple holes were made along the osteotomy path with Kirschner wire. Then osteotomy was performed with thin chisels. The thin chisels of 3 or 5 mm width were useful to connect the multiple holes on the circular arc part of the osteotomy line. After osteotomy, the distal tibial fragment was rotated distally in the coronal plane (i.e., clockwise for the right ankle and counterclockwise for the left) by a spreader and hand manipulated until ankle stability was achieved. The spreader could be inserted in the vertically osteotomized gap, and it was useful to rotate the distal tibial fragment along the osteotomy arc. As the distal tibial fragment was rotated distally, the width of the ankle mortice became narrow and the stabilized ankle was confirmed. If appropriate stability is not achieved, three dimensional displacement of the distal tibial fragment should be considered [10]. Artificial bone blocks (beta-tricalcium phosphate) were inserted in the wedge-shaped gap (Fig. 2D). Local bone grafting was performed using tibial bone resected from the projection created by rotation (Fig. 1). A locking plate was then applied for stabilization (Figs. 2E and 3). Postoperative management: A short-leg splint was applied for 2 weeks. Ankle range-of-motion (ROM) exercises were started one week postoperatively. The patient was then allowed to walk with a
Table 2 Patient demographic data. Case
Sex
Age
OA stage
Follow-up period (months)
1 2 (left ankle) (right ankle) 3 4 5 6
Female Female
65 67 68 46 56 72 64
3a 3a 3a 2 3b 3a 3a
35 32 15 25 17 13 13
Female Male Female Female
Combined osteotomy Fibula Fibula Calcaneus
OA: osteoarthritis.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6
3
Fig. 1. Osteotomy design. A: The osteotomy path is the combination of a doglegged line and the arc of a virtual circle created by coronal-plane rotation of this line (solid line). B: The bone projection created by tibial rotation (hatched area with an arrow) can be resected and grafted into the gap (black).
Fig. 2. A representative case (case 5). A: Preoperative anteroposterior weight-bearing radiograph showing stage 3a ankle osteoarthritis. B: Preoperative lateral weight-bearing ankle radiograph. C: Intraoperative fluoroscopic view. A Kirschner wire was inserted from the lateral fibula percutaneously to the tibia to stabilize the distal tibiofibular syndesmosis temporarily. A short Kirschner wire was put around the center of the virtual circle as a reference point for osteotomy. D: The distal tibial fragment was rotated distally and an artificial bone block was inserted in the wedge-shaped gap. E: The periosteum was repaired and a locking plate was applied for stabilization.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
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K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6
Fig. 3. One-year postoperative weight-bearing ankle radiographs. A: Anteroposterior view. B: Lateral view.
patella tendon-bearing brace. At six weeks postoperatively, weightbearing was allowed depending on the rate of osteotomy healing. Clinical improvements were evaluated using the Japanese Society for Surgery of the Foot (JSSF) ankleehindfoot scale [17]. The Self-Administered Foot Evaluation Questionnaire (SAFE-Q) was used as patient-based outcome measurement. SAFE-Q has been developed as a QOL questionnaire instrument for use in pathological conditions related to the foot and ankle and the reliability has been validated [18]. Postoperative complications such as infection, wound complications, and nerve disturbances were recorded. Radiographic evaluation was performed to assess the period until bone union and the postoperative alignment of the ankle. Preoperative and postoperative radiographic parameters measured were (1) TAS (the angle between the tibial shaft and the tibial joint surface on the anteroposterior view), (2) TLS (the angle of the tibial joint surface on the lateral view), and (3) TMM (the angle of the medial malleolus on the anteroposterior view) [4]. 3. Results Three of the seven ankles received combined procedures, fibular osteotomy in 2 ankles and lateral sliding osteotomy of the calcaneus in one ankle (Table 2). The mean JSSF ankleehindfoot scale improved from 38.4 points preoperatively to 85.7 points at the latest follow-up (Table 3). Postoperative SAFE-Q data were presented in Table 3. The bilateral operated case (case 2) showed relatively low scores in the subscales of “physical functioning and daily living”, “social functioning”, and “general health and well-being”. The other cases showed favorable outcomes of selfevaluated QOL. Sutures were removed within 2 weeks postoperatively in all patients and no wound problems, infections, or nerve disturbances were observed. Bone union was achieved within 3 months in all the patients as evaluated radiographically. All radiographic parameters (TAS, TLS, and TMM) were improved following the operation (Tables 3 and 4).
Representative case: A 72-year-old female (case 5) suffered pain during weight bearing on her right ankle and visited our clinic. After conservative treatment failed, she underwent the distal tibial rotational osteotomy (Fig. 2). Beta-tricalcium phosphate artificial bone blocks (OSferion 60, Olympus Co., Tokyo, Japan) were inserted in the gap of the tibia. Local bone grafting was performed using the Table 3 Patient clinical and radiographic parameters. Case
1 2 (left) (right) 3 4 5 6 Case
JSSF scale
TAS
Pre.
Post.
Pre.
Post.
Pre.
TLS Post.
Pre.
TMM Post.
38 34 34 36 35 57 35
90 85 85 85 85 85 85
83 82 79.5 84.5 86 84.5 83
91 90 90 97 95 97 91.5
77.5 76 77.5 84 83 79.5 83.5
79 77 79 85 83 82 82.5
49 51 34 25 44 41 30.5
39 40 25 16 36 22.5 23.5
Postoperative SAFE-Q Social Shoe-related General Pain and Physical functioning health and pain-related functioning well-being and daily living
1 2 (left) (right) 3 4 5 6
76.3 77.6 100 80.8 81.3 82.2 76.4
88.6 65.9 70.5 84.1 75 84.1 77.3
100 66.7 66.7 83.3 91.7 83.3 83.3
58.3 83.3 83.3 66.7 91.7 66.7 41.7
100 65 65 80 95 90 80
JSSF scale: the Japanese Society for Surgery of the Foot ankleehindfoot scale. TAS: the angle between the tibial shaft and the tibial joint surface on the anteroposterior view. TLS: the angle of the tibial joint surface on the lateral view. TMM: the angle of the medial malleolus (from Takakura et al., 1995; Tanaka et al., 2006). SAFE-Q: the Self-Administered Foot Evaluation Questionnaire. Pre.: preoperative. Post.: postoperative.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6 Table 4 Preoperative and postoperative radiographic parameters following tibial osteotomy for varus ankle osteoarthritis. Study
TAS
(reported year)
Pre.
Post.
Pre.
TLS Post.
Pre.
TMM Post.
Takakura et al. (1995) Tanaka et al. (2006) Sakamoto et al. (2014) Kim et al. (2014) Ahn et al. (2015) Kobayashi et al. (2016) Hongmou et al. (2016) Current study
82.2 82.7 84.3 82.9 86.6 84.9 81.2 83.2
93.8 98.2 92.8 89.5 92.9 95.0 88.3 93.1
77.4 78.5 80.2 77.1 81.1
81.6 84.7 80.9 78.8 84.3
43.5
26.9
28.4
20.1
82.7 80.1
83.5 81.1
39.2
28.9
TAS: the angle between the tibial shaft and the tibial joint surface on the anteroposterior view. TLS: the angle of the tibial joint surface on the lateral view. TMM: the angle of the medial malleolus (from Takakura et al., 1995; Tanaka et al., 2006). Pre.: preoperative. Post.: postoperative. The values indicate mean angles (in degrees).
resected tibial bone projection created by tibial rotation. A Locking Humerus Spoon Plate (Synthes Japan, Tokyo) was used as a lowprofile locking plate for tibial stabilization. One year postoperatively, her ankle pain was relieved and she could perform daily activities with no restriction. Postoperative radiographs of her weightbearing ankle showed complete bone fusion of the osteotomy site and the inserted artificial bone blocks with improved radiographic parameters (Fig. 3). The JSSF ankleehindfoot scale improved from 57 to 85. 4. Discussion Tibial osteotomy for ankle arthritis results in acceptable clinical outcome. Tanaka et al. [3] reported excellent or good clinical results in 19 of 26 ankles at 99 months following open-wedge LTO. Sakamoto et al. [6] also achieved good clinical results in 20 ankles at a mean follow-up of 68 months using open-wedge LTO, with improvement of the mean JSSF ankleehindfoot scale score from 61.3 to 83.3. Several investigations have reported significant clinical and radiographic improvements following DTOO [12e14]. These latter reports applied internal fixation with plates to stabilize the osteotomy site, and radiographic improvements were comparable in those in previous studies (Table 4). One potential concern of tibial open-wedge osteotomy, especially DTOO, is soft tissue/skin complication due to over-tension following displacement of the osteotomized distal tibial fragment, which could lead to severe problems such as infection and bone non-union. Teramoto et al. used an Ilizarov external fixator to avoid such soft tissue-related complications [8e10]. Another concern is non-union or delayed union following osteotomy of the tibia, which has been reported in up to 22% of patients [1]. High union rates were achieved using locking plates for fixation in recent reports [10,13,14]. Using our modified DTOO procedure, we were able to maintain tibial contact after the osteotomy by rotating the distal tibial fragment. Further, resection of the medial bone projection created by rotational displacement should reduce tension of the medial soft tissue. Moreover, the gap created by rotation was filled with artificial bone blocks and the resected tibial bone, thereby avoiding potential postoperative complications at a bone harvesting site (ileum). We also mitigated over-tension of the medial soft tissue and improved patient compliance in their daily activities by applying a low-profile locking plate for stabilization of the osteotomy site. Although the number of patients was small and the follow-up period short,
5
favorable clinical results and bone union were achieved in all cases with no postoperative complications. In addition, radiographic parameters were improved to a degree comparable with previous surgical methods (Table 4). We thus suggest that this modified DTOO procedure can achieve successful tibial union with minimal postoperative soft-tissue complications and harvesting site morbidity for patients with ankle osteoarthritis. It is important to confirm ankle joint stability achieved after displacement of the distal tibia. The original DTOO is three-dimensional displacement osteotomy to achieve ankle stability [8e11]. In our procedure if larger displacement leads to separation of the osteotomized tibia or instability at the osteotomy site, another type of locking plate or external fixation method such as Ilizarov external fixation should be considered as the original procedure indicates [10]. Limitations include the small sample size. In addition, we performed combined osteotomy in our early cases (fibula; 2, calcaneus; 1) to achieve valgus alignment, while most DTOO procedures reported previously were solely tibial osteotomies. Thus, it is difficult to directly compare results among procedures. Currently, we agree with this concept of single tibial osteotomy considering those previous favorable results and our experiences. Further, additional case series are required to clarify indications for this procedure, and longer follow-up periods are necessary to evaluate the long-term clinical efficacy relative to previous DTOOs. Conflict of interest The authors declare that they have no conflict of interest. References [1] Barg A, Pagenstert GI, Horisberger M, Paul J, Gloyer M, Henninger HB, Valderrabano V. Supramalleolar osteotomies for degenerative joint disease of the ankle joint: indication, technique and results. Int Orthop 2013 Sep;37(9):1683e95. [2] Knupp M, Stufkens SA, van Bergen CJ, Blankevoort L, Bolliger L, van Dijk CN, Hintermann B. Effect of supramalleolar varus and valgus deformities on the tibiotalar joint: a cadaveric study. Foot Ankle Int 2011 Jun;32(6):609e15. [3] Tanaka Y, Takakura Y, Hayashi K, Taniguchi A, Kumai T, Sugimoto K. Low tibial osteotomy for varus-type osteoarthritis of the ankle. J Bone Joint Surg Br 2006 Jul;88(7):909e13. [4] Takakura Y, Tanaka Y, Kumai T, Tamai S. Low tibial osteotomy for osteoarthritis of the ankle. Results of a new operation in 18 patients. J Bone Joint Surg Br 1995 Jan;77(1):50e4. [5] Lee WC, Moon JS, Lee K, Byun WJ, Lee SH. Indications for supramalleolar osteotomy in patients with ankle osteoarthritis and varus deformity. J Bone Joint Surg Am 2011 Jul 6;93(13):1243e8. [6] Sakamoto T, Imamura I, Goto M, Kita A. Clinical results of low tibial osteotomy for osteoarthritis of the ankle joint. J Jpn Soc Surg Foot 2014 Sep;35(1):112e5 [in Japanese]. [7] Hongmou Z, Xiaojun L, Yi L, Hongliang L, Junhu W, Cheng L. Supramalleolar osteotomy with or without fibular osteotomy for varus ankle arthritis. Foot Ankle Int 2016 Sep;37(9):1001e7. [8] Teramoto T, Nakamura S, Makino Y, Iwasaki. The application of Ilizarov external fixator for the osteotomy of tibia. J Jpn Soc Extern Fixat 1996 Feb;7:29e32. [9] Teramoto T, Tashiro K, Ohtsuka K, Takai M, Makino Y, Asahara T. The change in the instability of the ankle joint after distal tibial oblique osteotomy performed for the treatment of osteoarthritis of the ankle joint. J Jpn Assoc Extern Fixat Limb Lengthening 2009 Feb;20:119e26. [10] Teramoto T, Harada S, Takaki M, Asahara T, Kato N, Takenaka N, Matsushita T, Makino Y, Tasiro K, Kazutaka O, Nishi Y, Kinugsa K. The Teramoto distal tibial oblique osteotomy (DTOO): surgical technique and applicability for ankle osteoarthritis with varus deformity. Strateg Trauma Limb Reconstr 2018 Apr;13(1):43e9. https://doi.org/10.1007/s11751-018-0307-0. Epub 2018 Jan 29. [11] Teramoto T, Makino Y, Nobuyuki T, Tashiro K, Ohtsuka K, Asahara T, Takai M. Attentions of the osteoarthritis of the ankle joint treated by distal tibial oblique osteotomy. J Jpn Soc Surg Foot 2010 May;31(2):76e81 (in Japanese). [12] Kim YS, Park EH, Koh YG, Lee JW. Supramalleolar osteotomy with bone marrow stimulation for varus ankle osteoarthritis: clinical results and secondlook arthroscopic evaluation. Am J Sports Med 2014 Jul;42(7):1558e66. [13] Ahn TK, Yi Y, Cho JH, Lee WC. A cohort study of patients undergoing distal tibial osteotomy without fibular osteotomy for medial ankle arthritis with mortise widening. J Bone Joint Surg Am 2015 Mar 4;97(5):381e8. [14] Kobayashi H, Kageyama Y, Shido Y. Treatment of varus ankle osteoarthritis and instability with a novel mortise-plasty osteotomy procedure. J Foot Ankle Surg 2016 Jan-Feb;55(1):60e7.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
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K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6
[15] Stamatis ED, Cooper PS, Myerson MS. Supramalleolar osteotomy for the treatment of distal tibial angular deformities and arthritis of the ankle joint. Foot Ankle Int 2003 Oct;24(10):754e64. [16] Mann HA, Filippi J, Myerson MS. Intra-articular opening medial tibial wedge osteotomy (plafond-plasty) for the treatment of intra-articular varus ankle arthritis and instability. Foot Ankle Int 2012 Apr;33(4): 255e61.
[17] Niki H, Aoki H, Inokuchi S, Ozeki S, Kinoshita M, Kura H, Tanaka Y, Noguchi M, Nomura S, Hatori M, Tatsunami S. Development and reliability of a standard rating system for outcome measurement of foot and ankle disorders I: development of standard rating system. J Orthop Sci 2005 Sep;10(5):457e65. [18] Niki H, Tatsunami S, Haraguchi N, Aoki T, Okuda R, Suda Y, Takao M, Tanaka Y. Validity and reliability of a self-administered foot evaluation questionnaire (SAFE-Q). J Orthop Sci 2013 Mar;18(2):298e320.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Original Article
Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results Kota Watanabe a, *, Atsushi Teramoto b, Takuma Kobayashi b, Yuzuru Sakakibara b, Hiroaki Shoji b, Shinichiro Okimura b, Satoshi Nuka c, Toshihiko Yamashita b a b c
Department of Physical Therapy, Sapporo Medical University School of Health Sciences, South-1, West-17, Chuoku, Sapporo, Hokkaido, 060-8556, Japan Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1, West-16, Chuoku, Sapporo, Hokkaido, 060-8543, Japan Department of Orthopaedic Surgery, Hakodate Goryokaku Hospital, 38-3, Goryokakuchou, Hakodate, Hokkaido, 0400001, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 2 February 2017 Received in revised form 23 April 2018 Accepted 29 August 2018 Available online xxx
Background: Low tibial osteotomy is an effective joint-preserving surgery for ankle arthritis. However, poor postoperative wound healing, infection, and delayed or non-union of bones remain significant concerns. We describe a modified distal tibial oblique osteotomy procedure and report preliminary results for varus ankle arthritis. Methods: The osteotomy path consisted of an oblique doglegged line from the lateral end of the distal tibia to a proximal point about one-third from the lateral edge and continuing along an arc defined by virtual coronal-plane rotation of the doglegged line to the medial edge. After osteotomy, the distal tibial fragment was rotated distally in the coronal plane for realignment while maintaining contact with the proximal tibia and the distal tibial fragment. The resulting wedge-shaped gap was filled with artificial bone blocks and tibial bone projecting medially from rotation. A locking plate was then applied for stabilization. We evaluated 7 ankles from 6 osteoarthritis patients both clinically and radiographically following this procedure. Results: Bone union was achieved within 3 months for all patients. The Japanese Society for Surgery of the Foot ankleehindfoot scale improved from a mean of 38.4 points preoperatively to 85.7 points at the latest follow-up. No wound healing problems, infections, or nerve disturbances were observed. Multiple radiographic parameters were also improved following the operation. Conclusions: This procedure maintains close bone contact for better postoperative union, obviates the need for iliac bone harvesting, and reduces tension on medial soft tissue. We believe these modifications are potential advantages for achieving stable results in patients with ankle osteoarthritis. © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
1. Introduction Supramalleolar low tibial osteotomy (LTO) is an effective operative procedure for the management of ankle arthritis with varus or valgus deformity. Indeed, open-wedge, closed-wedge, and intraarticular variants of LTO can correct biomechanical abnormalities like aberrant pressure distribution in the tibiotalar joint by realigning the deformity [1,2]. Early and mid-stage ankle osteoarthritis are generally accepted as indications for these procedures.
* Corresponding author. Department of Physical Therapy, Sapporo Medical University School of Health Sciences, South-1, West-17, Chuoku, Sapporo, Hokkaido, 060-8556, Japan. Fax: þ11 641 6026. E-mail address: [email protected] (K. Watanabe).
For instance, Tanaka et al. reported that LTO was indicated for varus-type stage 2 or stage 3a osteoarthritis (Table 1) [3]. Previous investigators reported clinically significant pain relief and functional improvement following these procedures [1,3e16]. Open-wedge LTO in particular has been widely used for varus ankle arthritis. In this procedure, the osteotomy line is parallel or slightly oblique to the distal tibial articular surface, with a medial point about 5 cm above the tip of the medial malleolus. In most cases, tibial osteotomy is combined with fibular osteotomy [3e7,15]. Teramoto et al. developed distal tibial oblique osteotomy (DTOO) and achieved good outcomes in stage 3b or 4 patients [8e10] In this procedure, the distal tibia is osteotomized obliquely toward the distal tibiofibular joint. The distal tibial fragment is spread until the lateral articular surface of the talus contacts the medial articular surface of the lateral malleolus. Iliac bone is then
https://doi.org/10.1016/j.jos.2018.08.020 0949-2658/© 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
2
K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6 Table 1 Classification of varus ankle osteoarthritis (from Takakura et al., 1995; Tanaka et al., 2006). Stage
Characteristics
1 2 3a 3b 4
No narrowing of the joint-space, but early sclerosis and formation of osteophytes Narrowing of the medial joint space Obliteration of the medial joint space with subchondral bone contact. The obliteration is limited to the medial malleolus Obliteration of the medial joint space with subchondral bone contact. The obliteration extends to the roof of the dome of the talus Obliteration of the whole joint space with complete bone contact
grafted into the spreading space and an Ilizarov external fixator or a locking plate is used to stabilize the osteotomy site. This DTOO operation can restore the congruence of the tibiotalar joint surface, improving both the alignment and stability of the ankle joint. Favorable outcomes have also been reported using similar tibial osteotomy designs [12e14]. While these realignment osteotomies can lead to good clinical outcomes, there are still risks of postoperative complications. Soft tissue is thin around the osteotomy site and over-tension of the soft tissue may occur following realignment or internal fixation with implants. Indeed, several complications have been reported following supramalleolar osteotomies for ankle osteoarthritis, including wound healing problems, infection, delayed/non-union of bone, and painful hardware [1]. Another potential concern is morbidity associated with harvesting iliac crest for the bone graft. We have also observed non-union cases following LTO and complications at the iliac crest bone harvesting site. To improve outcome and reduce complications, we have developed a modified DTOO procedure. The purposes of this study are to introduce our procedure and report results for varus ankle arthritis. 2. Patients and methods This study included 7 ankles of 6 patients (6 female, 1 male) with ankle osteoarthritis. Approval for this study was granted by our institutional review board (IRB) and informed consent was obtained from each patient. Radiographic ankle osteoarthritis stage according to the Takakura-Tanaka classification ranged from 2 to 3b [3,4]. All patients had suffered from their affected ankles for more than one year and were treated conservatively for at least 6 months. Patient demographic data are shown in Table 2. Operative procedure: The procedure developed is modified from ankle mortise reconstruction, which has been reported as DTOO [8e10,13] or distal tibial rotational osteotomy (DTRO) [9,11]. The purpose of DTOO is to improve the alignment and stability of the ankle joint [9e11]. During the operation multidirectional stress tests are performed to confirm ankle joint stability by using an image intensifier. Modification of this procedure was devised to achieve the following: (1) Maintained contact of the distal and proximal tibial bones after osteotomy, (2) No bone harvesting from other sites (iliac bone), and (3) Usage of an internal fixation (plate) for stabilization. The planned osteotomy path combined a doglegged line
from the lateral edge of the distal tibia and an arc defined by virtual coronal-plane rotation of this line (Fig. 1). The center of this virtual circle was set at the lateral edge of the distal tibia. The radius of this circle was the horizontal distance from the circle center to the medial tibial surface. The osteotomy arc was designed on the virtual circle with the lateral tibial cortex spared. Basically we set the width of the osteotomy arc to two-third of the transverse diameter of the tibia to avoid fracture. The oblique osteotomy line from the center of the virtual circle was an equiangular bisector of the distal tibial lateral portion (about 45 from the articular surface of the distal tibia). This line was connected with the vertical line from the lateral end of the osteotomy arc. The patient lay on the operative table in a supine position with a tourniquet. A Kirschner wire was inserted from the lateral fibula percutaneously to the tibia under fluoroscopic guidance to stabilize the distal tibiofibular syndesmosis temporarily and avoid displacement when the distal tibial fragment was rotated in the coronal plan after osteotomy. It was helpful to put a short Kirschner wire at the center of the virtual circle to identify this point for osteotomy (Fig. 2C). An L-shaped incision was used to expose medial and anterior aspects of the distal tibia, and the periosteum was peeled off along the osteotomy path. Multiple holes were made along the osteotomy path with Kirschner wire. Then osteotomy was performed with thin chisels. The thin chisels of 3 or 5 mm width were useful to connect the multiple holes on the circular arc part of the osteotomy line. After osteotomy, the distal tibial fragment was rotated distally in the coronal plane (i.e., clockwise for the right ankle and counterclockwise for the left) by a spreader and hand manipulated until ankle stability was achieved. The spreader could be inserted in the vertically osteotomized gap, and it was useful to rotate the distal tibial fragment along the osteotomy arc. As the distal tibial fragment was rotated distally, the width of the ankle mortice became narrow and the stabilized ankle was confirmed. If appropriate stability is not achieved, three dimensional displacement of the distal tibial fragment should be considered [10]. Artificial bone blocks (beta-tricalcium phosphate) were inserted in the wedge-shaped gap (Fig. 2D). Local bone grafting was performed using tibial bone resected from the projection created by rotation (Fig. 1). A locking plate was then applied for stabilization (Figs. 2E and 3). Postoperative management: A short-leg splint was applied for 2 weeks. Ankle range-of-motion (ROM) exercises were started one week postoperatively. The patient was then allowed to walk with a
Table 2 Patient demographic data. Case
Sex
Age
OA stage
Follow-up period (months)
1 2 (left ankle) (right ankle) 3 4 5 6
Female Female
65 67 68 46 56 72 64
3a 3a 3a 2 3b 3a 3a
35 32 15 25 17 13 13
Female Male Female Female
Combined osteotomy Fibula Fibula Calcaneus
OA: osteoarthritis.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6
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Fig. 1. Osteotomy design. A: The osteotomy path is the combination of a doglegged line and the arc of a virtual circle created by coronal-plane rotation of this line (solid line). B: The bone projection created by tibial rotation (hatched area with an arrow) can be resected and grafted into the gap (black).
Fig. 2. A representative case (case 5). A: Preoperative anteroposterior weight-bearing radiograph showing stage 3a ankle osteoarthritis. B: Preoperative lateral weight-bearing ankle radiograph. C: Intraoperative fluoroscopic view. A Kirschner wire was inserted from the lateral fibula percutaneously to the tibia to stabilize the distal tibiofibular syndesmosis temporarily. A short Kirschner wire was put around the center of the virtual circle as a reference point for osteotomy. D: The distal tibial fragment was rotated distally and an artificial bone block was inserted in the wedge-shaped gap. E: The periosteum was repaired and a locking plate was applied for stabilization.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
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K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6
Fig. 3. One-year postoperative weight-bearing ankle radiographs. A: Anteroposterior view. B: Lateral view.
patella tendon-bearing brace. At six weeks postoperatively, weightbearing was allowed depending on the rate of osteotomy healing. Clinical improvements were evaluated using the Japanese Society for Surgery of the Foot (JSSF) ankleehindfoot scale [17]. The Self-Administered Foot Evaluation Questionnaire (SAFE-Q) was used as patient-based outcome measurement. SAFE-Q has been developed as a QOL questionnaire instrument for use in pathological conditions related to the foot and ankle and the reliability has been validated [18]. Postoperative complications such as infection, wound complications, and nerve disturbances were recorded. Radiographic evaluation was performed to assess the period until bone union and the postoperative alignment of the ankle. Preoperative and postoperative radiographic parameters measured were (1) TAS (the angle between the tibial shaft and the tibial joint surface on the anteroposterior view), (2) TLS (the angle of the tibial joint surface on the lateral view), and (3) TMM (the angle of the medial malleolus on the anteroposterior view) [4]. 3. Results Three of the seven ankles received combined procedures, fibular osteotomy in 2 ankles and lateral sliding osteotomy of the calcaneus in one ankle (Table 2). The mean JSSF ankleehindfoot scale improved from 38.4 points preoperatively to 85.7 points at the latest follow-up (Table 3). Postoperative SAFE-Q data were presented in Table 3. The bilateral operated case (case 2) showed relatively low scores in the subscales of “physical functioning and daily living”, “social functioning”, and “general health and well-being”. The other cases showed favorable outcomes of selfevaluated QOL. Sutures were removed within 2 weeks postoperatively in all patients and no wound problems, infections, or nerve disturbances were observed. Bone union was achieved within 3 months in all the patients as evaluated radiographically. All radiographic parameters (TAS, TLS, and TMM) were improved following the operation (Tables 3 and 4).
Representative case: A 72-year-old female (case 5) suffered pain during weight bearing on her right ankle and visited our clinic. After conservative treatment failed, she underwent the distal tibial rotational osteotomy (Fig. 2). Beta-tricalcium phosphate artificial bone blocks (OSferion 60, Olympus Co., Tokyo, Japan) were inserted in the gap of the tibia. Local bone grafting was performed using the Table 3 Patient clinical and radiographic parameters. Case
1 2 (left) (right) 3 4 5 6 Case
JSSF scale
TAS
Pre.
Post.
Pre.
Post.
Pre.
TLS Post.
Pre.
TMM Post.
38 34 34 36 35 57 35
90 85 85 85 85 85 85
83 82 79.5 84.5 86 84.5 83
91 90 90 97 95 97 91.5
77.5 76 77.5 84 83 79.5 83.5
79 77 79 85 83 82 82.5
49 51 34 25 44 41 30.5
39 40 25 16 36 22.5 23.5
Postoperative SAFE-Q Social Shoe-related General Pain and Physical functioning health and pain-related functioning well-being and daily living
1 2 (left) (right) 3 4 5 6
76.3 77.6 100 80.8 81.3 82.2 76.4
88.6 65.9 70.5 84.1 75 84.1 77.3
100 66.7 66.7 83.3 91.7 83.3 83.3
58.3 83.3 83.3 66.7 91.7 66.7 41.7
100 65 65 80 95 90 80
JSSF scale: the Japanese Society for Surgery of the Foot ankleehindfoot scale. TAS: the angle between the tibial shaft and the tibial joint surface on the anteroposterior view. TLS: the angle of the tibial joint surface on the lateral view. TMM: the angle of the medial malleolus (from Takakura et al., 1995; Tanaka et al., 2006). SAFE-Q: the Self-Administered Foot Evaluation Questionnaire. Pre.: preoperative. Post.: postoperative.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
K. Watanabe et al. / Journal of Orthopaedic Science xxx (2018) 1e6 Table 4 Preoperative and postoperative radiographic parameters following tibial osteotomy for varus ankle osteoarthritis. Study
TAS
(reported year)
Pre.
Post.
Pre.
TLS Post.
Pre.
TMM Post.
Takakura et al. (1995) Tanaka et al. (2006) Sakamoto et al. (2014) Kim et al. (2014) Ahn et al. (2015) Kobayashi et al. (2016) Hongmou et al. (2016) Current study
82.2 82.7 84.3 82.9 86.6 84.9 81.2 83.2
93.8 98.2 92.8 89.5 92.9 95.0 88.3 93.1
77.4 78.5 80.2 77.1 81.1
81.6 84.7 80.9 78.8 84.3
43.5
26.9
28.4
20.1
82.7 80.1
83.5 81.1
39.2
28.9
TAS: the angle between the tibial shaft and the tibial joint surface on the anteroposterior view. TLS: the angle of the tibial joint surface on the lateral view. TMM: the angle of the medial malleolus (from Takakura et al., 1995; Tanaka et al., 2006). Pre.: preoperative. Post.: postoperative. The values indicate mean angles (in degrees).
resected tibial bone projection created by tibial rotation. A Locking Humerus Spoon Plate (Synthes Japan, Tokyo) was used as a lowprofile locking plate for tibial stabilization. One year postoperatively, her ankle pain was relieved and she could perform daily activities with no restriction. Postoperative radiographs of her weightbearing ankle showed complete bone fusion of the osteotomy site and the inserted artificial bone blocks with improved radiographic parameters (Fig. 3). The JSSF ankleehindfoot scale improved from 57 to 85. 4. Discussion Tibial osteotomy for ankle arthritis results in acceptable clinical outcome. Tanaka et al. [3] reported excellent or good clinical results in 19 of 26 ankles at 99 months following open-wedge LTO. Sakamoto et al. [6] also achieved good clinical results in 20 ankles at a mean follow-up of 68 months using open-wedge LTO, with improvement of the mean JSSF ankleehindfoot scale score from 61.3 to 83.3. Several investigations have reported significant clinical and radiographic improvements following DTOO [12e14]. These latter reports applied internal fixation with plates to stabilize the osteotomy site, and radiographic improvements were comparable in those in previous studies (Table 4). One potential concern of tibial open-wedge osteotomy, especially DTOO, is soft tissue/skin complication due to over-tension following displacement of the osteotomized distal tibial fragment, which could lead to severe problems such as infection and bone non-union. Teramoto et al. used an Ilizarov external fixator to avoid such soft tissue-related complications [8e10]. Another concern is non-union or delayed union following osteotomy of the tibia, which has been reported in up to 22% of patients [1]. High union rates were achieved using locking plates for fixation in recent reports [10,13,14]. Using our modified DTOO procedure, we were able to maintain tibial contact after the osteotomy by rotating the distal tibial fragment. Further, resection of the medial bone projection created by rotational displacement should reduce tension of the medial soft tissue. Moreover, the gap created by rotation was filled with artificial bone blocks and the resected tibial bone, thereby avoiding potential postoperative complications at a bone harvesting site (ileum). We also mitigated over-tension of the medial soft tissue and improved patient compliance in their daily activities by applying a low-profile locking plate for stabilization of the osteotomy site. Although the number of patients was small and the follow-up period short,
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favorable clinical results and bone union were achieved in all cases with no postoperative complications. In addition, radiographic parameters were improved to a degree comparable with previous surgical methods (Table 4). We thus suggest that this modified DTOO procedure can achieve successful tibial union with minimal postoperative soft-tissue complications and harvesting site morbidity for patients with ankle osteoarthritis. It is important to confirm ankle joint stability achieved after displacement of the distal tibia. The original DTOO is three-dimensional displacement osteotomy to achieve ankle stability [8e11]. In our procedure if larger displacement leads to separation of the osteotomized tibia or instability at the osteotomy site, another type of locking plate or external fixation method such as Ilizarov external fixation should be considered as the original procedure indicates [10]. Limitations include the small sample size. In addition, we performed combined osteotomy in our early cases (fibula; 2, calcaneus; 1) to achieve valgus alignment, while most DTOO procedures reported previously were solely tibial osteotomies. Thus, it is difficult to directly compare results among procedures. Currently, we agree with this concept of single tibial osteotomy considering those previous favorable results and our experiences. Further, additional case series are required to clarify indications for this procedure, and longer follow-up periods are necessary to evaluate the long-term clinical efficacy relative to previous DTOOs. Conflict of interest The authors declare that they have no conflict of interest. References [1] Barg A, Pagenstert GI, Horisberger M, Paul J, Gloyer M, Henninger HB, Valderrabano V. Supramalleolar osteotomies for degenerative joint disease of the ankle joint: indication, technique and results. Int Orthop 2013 Sep;37(9):1683e95. [2] Knupp M, Stufkens SA, van Bergen CJ, Blankevoort L, Bolliger L, van Dijk CN, Hintermann B. Effect of supramalleolar varus and valgus deformities on the tibiotalar joint: a cadaveric study. Foot Ankle Int 2011 Jun;32(6):609e15. [3] Tanaka Y, Takakura Y, Hayashi K, Taniguchi A, Kumai T, Sugimoto K. Low tibial osteotomy for varus-type osteoarthritis of the ankle. J Bone Joint Surg Br 2006 Jul;88(7):909e13. [4] Takakura Y, Tanaka Y, Kumai T, Tamai S. Low tibial osteotomy for osteoarthritis of the ankle. Results of a new operation in 18 patients. J Bone Joint Surg Br 1995 Jan;77(1):50e4. [5] Lee WC, Moon JS, Lee K, Byun WJ, Lee SH. Indications for supramalleolar osteotomy in patients with ankle osteoarthritis and varus deformity. J Bone Joint Surg Am 2011 Jul 6;93(13):1243e8. [6] Sakamoto T, Imamura I, Goto M, Kita A. Clinical results of low tibial osteotomy for osteoarthritis of the ankle joint. J Jpn Soc Surg Foot 2014 Sep;35(1):112e5 [in Japanese]. [7] Hongmou Z, Xiaojun L, Yi L, Hongliang L, Junhu W, Cheng L. Supramalleolar osteotomy with or without fibular osteotomy for varus ankle arthritis. Foot Ankle Int 2016 Sep;37(9):1001e7. [8] Teramoto T, Nakamura S, Makino Y, Iwasaki. The application of Ilizarov external fixator for the osteotomy of tibia. J Jpn Soc Extern Fixat 1996 Feb;7:29e32. [9] Teramoto T, Tashiro K, Ohtsuka K, Takai M, Makino Y, Asahara T. The change in the instability of the ankle joint after distal tibial oblique osteotomy performed for the treatment of osteoarthritis of the ankle joint. J Jpn Assoc Extern Fixat Limb Lengthening 2009 Feb;20:119e26. [10] Teramoto T, Harada S, Takaki M, Asahara T, Kato N, Takenaka N, Matsushita T, Makino Y, Tasiro K, Kazutaka O, Nishi Y, Kinugsa K. The Teramoto distal tibial oblique osteotomy (DTOO): surgical technique and applicability for ankle osteoarthritis with varus deformity. Strateg Trauma Limb Reconstr 2018 Apr;13(1):43e9. https://doi.org/10.1007/s11751-018-0307-0. Epub 2018 Jan 29. [11] Teramoto T, Makino Y, Nobuyuki T, Tashiro K, Ohtsuka K, Asahara T, Takai M. Attentions of the osteoarthritis of the ankle joint treated by distal tibial oblique osteotomy. J Jpn Soc Surg Foot 2010 May;31(2):76e81 (in Japanese). [12] Kim YS, Park EH, Koh YG, Lee JW. Supramalleolar osteotomy with bone marrow stimulation for varus ankle osteoarthritis: clinical results and secondlook arthroscopic evaluation. Am J Sports Med 2014 Jul;42(7):1558e66. [13] Ahn TK, Yi Y, Cho JH, Lee WC. A cohort study of patients undergoing distal tibial osteotomy without fibular osteotomy for medial ankle arthritis with mortise widening. J Bone Joint Surg Am 2015 Mar 4;97(5):381e8. [14] Kobayashi H, Kageyama Y, Shido Y. Treatment of varus ankle osteoarthritis and instability with a novel mortise-plasty osteotomy procedure. J Foot Ankle Surg 2016 Jan-Feb;55(1):60e7.
Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020
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[15] Stamatis ED, Cooper PS, Myerson MS. Supramalleolar osteotomy for the treatment of distal tibial angular deformities and arthritis of the ankle joint. Foot Ankle Int 2003 Oct;24(10):754e64. [16] Mann HA, Filippi J, Myerson MS. Intra-articular opening medial tibial wedge osteotomy (plafond-plasty) for the treatment of intra-articular varus ankle arthritis and instability. Foot Ankle Int 2012 Apr;33(4): 255e61.
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Please cite this article in press as: Watanabe K, et al., Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results, Journal of Orthopaedic Science (2018), https://doi.org/10.1016/j.jos.2018.08.020