Effectiveness of distal tibial osteotomy with distraction arthroplasty in varus ankle osteoarthritis
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In highly active older individuals, end-stage ankle osteoarthritis has traditionally been treated using tibiotalar arthrodesis, which provides considerable pain relief. However, there is a loss of ankle joint movement and a risk of future arthrosis in the adjacent joints. Distraction arthroplasty is a simple method that allows joint cartilage repair; however, the results are currently mixed, with some reports showing improved pain scores and others showing no improvement. Distal tibial osteotomy (DTO) without fibular osteotomy is a type of joint preservation surgery that has garnered attention in recent years. However, to our knowledge, there are no reports on DTO with joint distraction using a circular external fixator. Therefore, the purpose of this study was to examine the effect of DTO with joint distraction using a circular external fixator for treating ankle osteoarthritis.
A total of 21 patients with medial ankle arthritis were examined. Arthroscopic synovectomy and a microfracture procedure were performed, followed by angled osteotomy and correction of the distal tibia; the ankle joint was then stabilized after its condition improved. An external fixator was used in all patients, and joint distraction of approximately 5.8 mm was performed. All patients were allowed full weight-bearing walking immediately after surgery.
The anteroposterior and lateral mortise angle during weight-bearing, talar tilt angle, and anterior translation of the talus on ankle stress radiography were improved significantly (P < 0.05). Signal changes on magnetic resonance imaging also improved in all patients. Visual analog scale and American Orthopedic Foot & Ankle Society scores improved significantly (P < 0.05), and no severe complications were observed.
DTO with joint distraction may be useful as a joint-preserving surgery for medial ankle osteoarthritis in older patients with high levels of physical activity.
Level of evidence
Level IV, retrospective case series.
KeywordsDistal tibial osteotomy Medial ankle arthritis Joint distraction Circular external fixator
The American Orthopedic Foot & Ankle Society
Distal tibial osteotomy
low tibial osteotomy
Magnetic resonance imaging
The Patient Archiving and Communication System
Range of motion
Visual Analogue Scale
To date, ankle arthrodesis or total ankle arthroplasty has been performed in patients with progressive or end-stage ankle osteoarthritis. With the emergence of a super-aged society and an increased number of older patients with high levels of physical activity, joint-preserving surgery has become has become increasingly popular. The surgical treatment of ankle osteoarthritis varies according to the stage. In patients with stage II and IIIA ankle osteoarthritis, low tibial osteotomy (LTO) is indicated for correcting the alignment of the lower end of the tibia surface [1, 2, 3, 4, 5], whereas total ankle arthroplasty or arthrodesis is generally indicated for patients with end-stage arthropathy (stages IIIB and IV) [6, 7, 8, 9]. Intraarticular deformities may also be treated with total ankle arthroplasty, and distraction arthroplasty is indicated for patients with stage III or IV arthropathy [10, 11, 12, 13, 14]. In younger-aged patients with post-traumatic osteoarthritis, distraction arthroplasty is often performed with an external fixator. However, Tellisi and Fragomen  reported that in terms of joint preservation in the osteoarthritic ankle, older patients (more than 60 years old) tend to have better outcomes with distraction arthroplasty than their younger counterparts. Horn and Fragomen  also reported that supramalleolar osteotomy using circular external fixation is an effective method for correcting distal tibial deformities in the adult population. Plafond-plasty is also well indicated for various stages of intra-articular varus ankle osteoarthritis (including stage IIIB) associated with ankle instability .
Distal tibial osteotomy (DTO) is a type of joint-preserving surgery allowing patients to reacquire ankle stability and achieve weight-bearing; hence, it has been reported that DTO using a site with remaining healthy cartilage is indicated for stage II-IIIB arthropathy. However, to our knowledge, there are no reports on DTO with joint distraction using a circular external fixator. Therefore, this study aimed to examine the effect of DTO on ankle osteoarthritis with joint distraction using a circular external fixator.
Twenty-one patients (7 males and 14 females; mean age: 68.2 years; age range: 60–80 years) with medial ankle osteoarthritis (Takakura classification stage IIIA: 4 cases and stage IIIB: 17 cases), who underwent DTO with joint distraction using a circular external fixator and had undergone ≥2 years of follow-up, were included in the study. Overall, 17, 2, 1, and 1 patients had primary ankle osteoarthritis, ankle rheumatoid arthritis, post-traumatic ankle osteoarthritis (tibial shaft fracture), and polio-related ankle osteoarthritis, respectively. The left side was affected in 12 patients. The patients were all highly active people, and included farmers, manual laborer, and sports enthusiasts; they had chronic ankle pain with swelling, stiffness, and difficulty in walking, all of which are symptoms of ankle osteoarthritis.
The mean period to bone union was 85.0 days (range, 77–121 days). The mean period with an external fixator was 89.2 days (range, 80–128 days) and the mean follow-up period was 3.2 years (range, 2–9 years). Magnetic resonance imaging (MRI) was performed at a mean of 11.2 months (range, 10–14 months) after frame removal. Pre- and postoperative images were obtained, as well as the latest X-ray. The Patient Archiving and Communication System (PACS) software was used, which allowed for remarkably consistent measurements on radiographs. We confirmed the absence of errors on the AP, lateral, and mortise views of the radiographs on every occasion, using the scale in PACS. We also checked for weightbearing on AP, lateral, and mortise views of the radiographs every 1 to 3 months, and assessed the arthropathic changes such as the appearance of loss of joint space, subchondral sclerosis, cysts, and eburnation.
The rate of improvement in MRI signal changes (preoperative versus postoperative) was also determined (Fig. 6). MRI was performed on a 1.5-T system; T1and T2-weighted sequences were utilized to assess signal changes.
The rate of adjacent joint arthritis was measured using pre- and post-operative visual analog scale (VAS) and American Orthopedic Foot and Ankle Society (AOFAS) scores.
The paired Student’s t-test was used to compare pre- and post-operative values. All data passed the normality and equal variance Shapiro–Wilk tests. P < 0.05 was considered statistically significant.
Before and after surgery comparison
Antero-posterior mortise angle during weight-bearing
80.5 ± 2.8°(77–86°)
98.0 ± 2.1° (96–102°)
Lateral mortise angle during weight-bearing
76.0 ± 2.6° (74–82°)
85.0 ± 1.6° (83–88°)
Talar tilt angle
19.5 ± 2.9° (14–24°)
3.0 ± 0.8° (2~4°)
Anterior translation of the talus
27 ± 4.2 mm (16–32 mm)
2.6 ± 0.7 mm (2~4 mm)
7.0 ± 4.3°(0–15°)
6.0 ± 4.0° (0–15°)
45.0 ± 8.2° (25–60°)
40.0 ± 8.4° (20~60°)
9.1 ± 1.4 (6–10)
1.6 ± 2.4 (0–6)
35.5 ± 8.6 (30–58)
88.4 ± 10.7 (58~100)
MRI signal changes before and after surgery
Signal change of MRI
Disappeared, 9 patients (42.9%)
Reduced, 12 patients (57.1%)
Disappeared, 4 patients (19.1%)
Reduced, 17 patients (80.9%)
All patients showed improvements in MRI T1-weighted image signal changes, with a disappearance of preoperative signal changes and a reduction in the signal change area in 9 and 12 patients, respectively; additionally, in MRI T2-weighted images, there was a disappearance of preoperative signal changes and a reduction in the signal change area in 3 and 18 patients, respectively.
None of the patients demonstrated radiographic evidence of arthropathic changes in the peripheral joints.
The ROM was preserved, with similar pre- and post-operative values. The VAS improved from a preoperative mean of 9.1 points to a postoperative mean of 1.6 points. Additionally, the AOFAS improved from a preoperative mean of 35.5 points to a postoperative mean of 88.4 points.
There were 14 superficial pin-tract infections, which were treated with empirical oral antibiotics and daily pin-tract dressings. None of the patients experienced skin disorders that required additional surgery, deep infection, deep venous thrombosis, nerve palsy, adjacent joint disorders, or arthrofibrosis. One patient (79-year-old female) was using a crutch to walk by 5 years after surgery. One patient transiently experienced mild postoperative pain at the iliac crest; however, this had disappeared at the latest follow-up.
Various options exist for the surgical treatment of ankle osteoarthritis. Selection of the optimal treatment requires a thorough consideration of the patient’s characteristics. In patients with progressive or end-stage ankle osteoarthritis, total ankle arthroplasty is indicated for cases with bilateral involvement or degeneration in the adjacent joints. However, total ankle arthroplasty is contraindicated in patients with infectious ankle osteoarthritis or severe deformities (≥15° varus and valgus deformity of the ankle joint); it is also not appropriate for patients with a high level of physical activity (including sports and farming), even if they are ≥60 years of age . Although ankle arthrodesis shows stable long-term outcomes and is effective in reducing pain, it has certain disadvantages including a loss in the ankle ROM and adjacent joint disorders. Furthermore, in countries such as Japan where people do not wear shoes and tend to sit on the floor in the house, patient satisfaction with ankle arthroplasty is relatively low [7, 9]. LTO includes valgus correction of the alignment and an outward shift of the weight-bearing line. The procedure has been reported to have good outcomes in patients with stage I-IIIA ankle osteoarthritis. However, LTO, which involves extra-articular osteotomy, is contraindicated in patients with ankle joint instability and may require additional surgery, such as ligament reconstruction [1, 19, 20].
Distraction arthroplasty includes cell mobilization from the bone marrow in the talus and tibial mortise (via a microfracture procedure or drilling), and requires treated patients to perform articulation while wearing an external fixator, allowing for an increased ROM. Joint traction for an appropriate period of time prevents damage to the regenerated tissue, and articulation promotes its maturation [18, 21]. In this study, we combined DTO and distraction arthroplasty. DTO has been shown to be effective in older patients with a high level of physical activity, as it preserves the ROM [22, 23]. In a study, DTO was successfully performed in patients with stage IIIB arthropathy and ankle joint instability. DTO offers certain advantages over arthrodesis, which include preservation of joint function and pain reduction. Another merit is that it exerts less influence on peripheral joints, which often cause problems in fixation. Hence, none of the patients in the present study had an adjacent joint disorder.
Deliberate flexion of the osteotomy serves to stabilize and provide more coverage to the talus. Since most patients with ankle osteoarthritis lack dorsiflexion, many surgeons are hesitant to flex the osteotomy and increase equinus. However, we overcame this issue by employing transverse Vulpius gastrocsoleus recession for increased equinus, which provided better coverage of the talus and shifted the healthier posterior cartilage anteriorly. This approach may have contributed to the observed good results.
The advantage of DTO over LTO is that it improves ankle joint stability by an angled osteotomy of the proximal tibial attachment site of the anterior tibiofibular ligament with valgus correction . Without fibular osteotomy, DTO is similar to LTO with fibular osteotomy, in that they both correct alignments. Both osteotomies may shift the weight-bearing axis laterally by angulation of the osteotomized distal part of the tibia. However, only DTO without fibular osteotomy can narrow the lateral mortise in cases of medial ankle arthritis with mortise widening . Therefore, DTO with joint distraction using a circular external fixator may also be beneficial to the cartilage [10, 24].
There are numerous reports on supramalleolar osteotomy with or without fibular osteotomy for varus ankle arthritis. Hongmou et al.  reported that fibular osteotomy may be necessary in supramalleolar osteotomy cases with a large talar tilt and small tibiocrural angles. Stufkens et al.  also reported that only supramalleolar osteotomy with fibular osteotomy shifts the pressure laterally for varus ankle arthritis. However, further research is required on this subject.
Since long-term non-weight-bearing leads to reduced walking ability in older patients, walking with a circular external fixator with strong fixation immediately after surgery may greatly benefit them and mechanical stimulation by weight-bearing may have additional effects. Conversely, DTO using a plate requires 1 to 2 months of non-weight-bearing [22, 23]. Caution is required with higher degrees of correction as it places a greater burden on soft tissues.
This study has certain limitations. First, patients may find the use of a circular external fixator uncomfortable. However, one of the major reasons explaining the absence of deep infections or soft tissue complications requiring additional surgery in this cohort, may be the avoidance of plate fixation. Additionally, improvement of talus instability without ligament reconstruction requires a relatively large opening (i.e., about 20 mm) at the osteotomy site in most patients; this substantially increases the tension on the medial soft tissue in most patients. Therefore, additional studies with a larger number of older patients with ankle osteoarthritis and a high level of physical activity, are needed to validate the suitability of DTO with distraction arthroplasty using a circular external fixator as a treatment option for end-stage ankle osteoarthritis.
In the treatment of patients with ankle osteoarthritis, it is important to consider the patient’s age and physical activity level while selecting the optimal surgical strategy.
DTO with joint distraction may be useful as joint-preserving surgery for medial ankle osteoarthritis in young patients, and in older patients with a high level of physical activity.
KN performed the surgery. MN helped with surgery and helped to draft the manuscript. TK, YK, HS, HK and SC assisted with the surgery. HT and YS helped draft the manuscript. All authors read and approved the final manuscript.
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Ethics approval and consent to participate
All participants received prior information about the study before providing their written informed consent in accordance with the declaration of Helsinki. The study was approved by the ethical committee of Akita University Hospital (registration number 1970).
Consent for publication
Written informed consent was obtained from the patients for publication of this research and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.
The authors declare that they have no competing interests.
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