Abstract
Purpose: During distal tibial oblique osteotomy, external fixators can increase pin site infection risk, whereas plates can cause wound necrosis, necessitating a compromise between soft-tissue position and length. We provide the first report of the early results of intramedullary nail fixation in these osteotomies for avoiding soft tissue complications. Methods: Ten ankles, classed as Takakura–Tanaka stages 3a to 4 and unclassified and treated via distal tibial oblique osteotomy for ankle osteoarthritis between 2017 and 2021, were included. Osteotomy was performed obliquely from the distal medial tibia to the tibiofibular joint. The distal tibial fragment was rotated distally in the coronal plane for realignment. An intramedullary nail fixation was applied for stabilization. The resulting gap was filled with iliac bone graft. Ankles were evaluated on the Japanese Society for Surgery of the Foot ankle–Hindfoot Scale and Self-Administered Foot Evaluation Questionnaire before surgery and at final follow-up. Radiographic assessments were performed. Results: Bone union was achieved within 3 months in all patients. There were no cases of wound necrosis or correction loss postsurgery. Japanese Society scale scores significantly improved from 40.3 ± 15.9 to 87.5 ± 12.6 (P < 0.01). Mean self-evaluation scale scores (pain and pain-related, physical functioning and daily living, social functioning, general health and well-being) improved significantly. shoe-related scores did not change significantly but improved. There was no correction loss after surgery, with an average widening of 24.2 mm and opening angle of 22.6° at the osteotomy site. Conclusion: Our study showed that intramedullary nail for fixation of the osteotomy site in distal tibial oblique osteotomy effectively prevents soft tissues complications even in osteotomy sites with large openings.
Keywords
Brief introduction
There are three main types of surgical treatment for ankle osteoarthritis (OA), ankle arthrodesis, total ankle arthroplasty, and osteotomy. Supramalleolar low tibial osteotomy (LTO) is a widely performed joint preservation procedure for the correction of alignment.1–3 Nevertheless, LTO is not indicated for end-stage ankle OA because of the broad loss of articular cartilage surface and disruption of the subtalar joint compensatory mechanism. 4 Thus, LTO is indicated for varus-type OA at stage 2 or 3a of the Takakura–Tanaka classification system. 5 To expand the indications for LTO, Teramoto et al. devised the distal tibial oblique osteotomy (DTOO) for patients with advanced-stage (stages 3b and 4) ankle OA and achieved good results. 6 During DTOO, the osteotomy site is opened until the articular surface of the lateral talar body comes into contact with the medial articular surface of the lateral malleolus. This causes enlargement of the opening distance, theoretically stretching the skin and soft tissue just above the osteotomy site. The medial part of the lower leg is particularly prone to circulatory disturbances because of its thin subcutaneous tissue. McFerran and Smith evaluated complications encountered in the treatment of plafond fractures, and the complication rate was 54%, comprising wound breakdown, deep soft tissue infection/osteomyelitis, and superficial wound infections. 7 Similarly, Ovadia and Beals reported that 16 patients out of 142 required soft tissue procedures for wound closure. 8 Moreover, osteotomy stabilization with a locking plate exacerbates skin and subcutaneous tissue damage. Watanabe et al. found that a potential concern with tibial open-wedge osteotomies, especially DTOO, is soft tissue or skin complications due to excessive tension following the displacement of the osteotomized distal tibial fragment, including severe problems such as infection and bone nonunion. 9 The correction angle may be insufficient to avoid skin and subcutaneous problems. Teramoto et al. have noted that if there is no previous scarring of the medial skin, and the osteotomy separation is less than 15 mm, a locking plate can be inserted without removing the medial tibial cortex and cancellous bone. The most important point is to avoid insufficient correction to facilitate plate insertion and wound closure. 6 Yet, even when an external fixator is used instead of a locking plate, there may still be problems. These include pin site infection and complexity of use. A study by Harada found that all 15 patients with traumatic OA who underwent intraarticular osteotomy and had the osteotomized bone fixed with a circular external fixator developed pin site infection. 10 Thus, an alternative fixation method to reduce these problems is necessary.
Intramedullary nail fixation has been widely used in the treatment of distal tibial fractures with good clinical results because the surrounding tissue with poor vascularity is preserved.11–13 The application of intramedullary nails for the fixation of osteotomy sites may be a useful means of reducing soft tissue complications in DTOO. There have been no previous reports on the fixation of osteotomy sites with intramedullary nails in ankle OA. Hence, this study aims to assess the early results of clinical outcomes of fixation of osteotomy sites with intramedullary nails in patients with ankle OA. We will assess bone union, correction loss, and soft tissue complications.
Materials and methods
Data source
Patient demographics.
OA: Osteoarthritis
Surgical procedure
Each patient was placed on the operating table in a supine position without a tourniquet. General anesthesia was performed, a 5-cm medial straight incision was made ∼7 cm proximal to the tibial articular surface on the medial side, and a subperiosteal exposure was created. Using X-ray image intensification, the starting point of the osteotomy was assessed to ensure it is ∼ 6 cm proximal to the tibial articular surface. Since a large bone graft was required due to the large opening angle at the osteotomy site, a skin incision of that size was necessary. The cut was made obliquely toward the center of the tibiofibular joint. A 1.5-mm Kirschner wire was driven from the proximal-medial to distal lateral in the coronal plane and toward the part ∼1.5 cm proximal to the tibial joint surface of the distal tibiofibular joint. The osteotomy was then performed using a bone saw and osteotome. A 1.5-mm Kirschner wire was inserted percutaneously from the lateral fibula to the tibia under fluoroscopic guidance to temporarily stabilize the distal tibiofibular syndesmosis and avoid displacement when the distal tibial fragment was rotated in the coronal plane after osteotomy. 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) using a spreader. The osteotomy site was spread until the medial malleolus came into contact with the talus, whereupon it was transiently fixed with Kirschner wire. The osteotomy site was spread further until the lateral malleolus came into contact with the talus, at which point, the Kirschner wire was removed. Osteophytes on the lateral malleolus surface were resected when the osteophytes between the tibiofibular joints prevented the valgus of the distal fragment. The osteophytes on the anterior side of the fibula were not excised because they are considered to contribute to the stability of the internal-external rotation. Manual manipulation was used to confirm that ankle stability had been achieved in the coronal plane. This stability occurs because the rotation of the distal tibial fragment narrows the width of the ankle mortise. The stability of the varus, valgus, forward pull, and internal-external rotation were assessed under fluoroscopy. If determined unstable, bone fragments were readjusted to achieve a stable position. 6 When the varus sway remained after correcting the tibial osteotomy during surgery, and it was judged that the fibula became relatively short due to the lengthening of the tibia, fibula lengthening was performed.
Then, the intramedullary nail was inserted by suprapatellar approach and fixed under fluoroscopic guidance (Figure 1). Phoenix Nail (Zimmer Biomet, Warsaw, IN, USA) was used in four cases and T2 Alpha (Stryker Trauma GmbH, Kiel-Schönkirchen, Germany) in six cases. At first, an intramedullary nail without a distal locking option had been used, but an intramedullary nail with a distal locking option has been used after it was commercially available in our country. The proximal and distal bone fragments were temporarily fixed in place with Kirschner wire in a position that would not interfere with the path of the intramedullary nail. A guide pin can be used at the site of osteotomy to control the tip of the reaming. Three interlocking screws at the distal and 2 screws at the proximal of the nail were used. The distal screws were inserted Representative case (case 3) of intramedullary nail fixation in distal tibia oblique osteotomy. 56-year-old female. She underwent surgery for Takakura-Tanaka class IIIa ankle osteoarthritis. The image shows proximal incisions for the intramedullary nail. Representative case (case 7). A 66-year-old man underwent surgery for Takakura-Tanaka Classification IIIb osteoarthritis of the ankle. The TAS angle improved from 81.9° before surgery to 103.2° after surgery. The TLS angle has improved from 83.4° to 84.5°. Intraoperative fluoroscopic view of intramedullary nail fixation in the distal tibial oblique osteotomy. A–C. A φ2.0 mm Kirschner wire was inserted percutaneously from lateral fibula to tibia to temporarily stabilize distal tibiofibular syndesmosis. Intramedullary nail was inserted. Representative case (case 7). A and B: preoperative radiographs; C and D: postoperative radiographs. The surgery was completed after confirming improvement in varus/valgus instability, plantar dorsiflexion instability, and internal/external rotation instability. There is no standard for improving instability, and it is determined by the feeling of the operator during surgery. The osteotomy is 30 mm dilated and the dilated angle is 28.6°. The TAS angle improved from 81.9° before surgery to 103.2° after surgery. The TLS angle has improved from 83.4° to 84.5°.


Evaluation of clinical outcomes
Clinical improvements were evaluated using the Japanese Society for Surgery of the Foot (JSSF) ankle and hindfoot scale. 15 The Self-Administered Foot Evaluation Questionnaire (SAFE-Q) was also used as a patient-based outcome measurement. SAFE-Q was developed for use with foot and ankle pathologies and the reliability has been validated. 16 Postoperative complications such as infection, wound complications, and neural disturbances were recorded. A radiographic evaluation was performed to determine the time taken until the bone union and the postoperative alignment of the ankle. Bone union was defined as adequate bridging of the lateral portion of the tibial osteotomy site on plain radiographs. Since the outer cortex at the osteotomy site was continuous in an open wedge osteotomy, the continuity of the single cortex was evaluated instead of the usual fracture criteria. The preoperative and postoperative radiographic parameters measured were (1) tibial articular surface angle (TAS—the angle between the tibial shaft and the tibial joint surface on the anteroposterior view), (2) tibial lateral surface angle (TLS—the angle of the tibial joint surface on the lateral view), (3) tibial medial malleolar angle (TMM—the angle of the medial malleolus on the anteroposterior view), 14 and (4) the opening distance and angle of the postoperative osteotomy site. Postoperative measurements were taken on the day of surgery and 3 months, 6 months, and 12 months after the surgery. TW and AM measured these parameters on plain radiograms and calculated from the average values.
Statistical analysis
All statistical analyses were performed with EZR, v.14 (Saitama Medical Center, Jichi Medical University, Saitama, Japan) software, a modified version of R commander designed to perform statistical functions (The R Foundation for Statistical Computing, Vienna, Austria). Continuous variables, including the JSSF scale, TAS, TMM, TLS were presented as the mean ± standard deviation and the differences between the preoperative and postoperative parameters were compared using paired t-tests. Differences were considered statistically significant at p < 0.05.
Results
Two of the 10 ankles required additional fibular osteotomy. In one case, the fibula was extended and stabilized because of the remaining instability after the tibial osteotomy and correction. In the other case, joint stability was obtained after the tibial osteotomy, but the ankle varus remained; thus, a fibula osteotomy was performed (Figure 4). The mean JSSF scores significantly improved from 40.3 ± 15.9 points preoperatively to 87.5 ± 12.6 points (p < 0.01) at the final follow-up (1 year postoperative). The mean preoperative and final follow-up scores on the SAFE-Q for each sub-measure were as follows: pain and pain-related scores improved significantly from 46.7 ± 11.1 to 76.3 ± 12.5 points (p < 0.01); physical functioning and daily living scores improved significantly from 53.0 ± 16.1 to 72.1 ± 12.4 points (p < 0.01); social functioning scores improved significantly from 58.3 ± 17.1 to 76.3 ± 13.3 points (p < 0.02); shoe-related scores did not change significantly but improved from 61.7 ± 19.3 to 74.2 ± 19.0 points (p = 0.162); general health and well-being scores improved significantly from 43.0 ± 19.3 to 74.5 ± 13.6 points (p < 0.01) (Table 2). Postoperatively, there were no wound problems and no cases of necrosis. There was one case of prophylactic relaxing incision due to high intraoperative skin tension, and three cases of superficial exudation lasting for 2–4 weeks. Bone union, confirmed radiographically, was achieved within 3 months by all patients. The mean TAS improved significantly from 81.65 ± 2.26 (°) preoperatively to 102.86 ± 5.49 (°) (p < 0.01). The mean TAS improved significantly from 80.79 ± 3.63 (°) preoperatively to 103.6 ± 5.09 (°) (p < 0.01). The mean TMM improved significantly from 40.0 ± 12.14 (°) preoperatively to 19.91 ± 10.56 (°) (p < 0.01). The mean TLS improved but not significantly from 79.33 ± 5.48 (°) preoperatively to 82.01 ± 6.40 (°) (p = 0.33) (Figure 5). Representative case (case 3). A 56-year-old woman underwent surgery for Takakura-Tanaka Classification IIIa osteoarthritis of the ankle. Since the varus sway remained after correcting the tibial osteotomy during surgery, it was judged that the fibula became relatively short due to the lengthening of the tibia, and fibula lengthening was performed. The current situation is that the determination of joint stability is not quantified and is left to the operator's senses, and this is a future issue. requiring fibula osteotomy after distal tibial oblique osteotomy due to residual instability. A: preoperative; B and C: postoperative radiographs. Comparison of pre and postoperative foot evaluation measure scores of patients with ankle osteoarthritis who underwent distal tibial oblique osteotomy with intramedullary nail fixation. JSSF, Japanese Society for Surgery of the Foot; SAFE-Q, self-administered foot evaluation questionnaire. Student’s t-test.
There was no change in the TAS and TLS angles immediately after surgery and at the 1 year follow-up, and there was no correction loss in any patient. The mean widening distance was 24.4 mm (14–30.3 mm), and the mean opening angle was 23.8° (14.6°–32.7°) (Figure 5). One patient complained of discomfort from the distal interlocking screw on the medial side of the lower leg, but the symptoms were mild and the screw was not removed. There was no adverse effect of harvesting the iliac bone. The mean tibial articular surface angle and tibial medial malleolar angle were significantly improved postoperatively. The mean tibial lateral surface angle improved postoperatively but not significantly.
Discussion
Despite an average opening distance of 24.4 mm, with a maximum of 30.3 mm, no major wound complications were observed in our sample. There was no loss of correction, and all patients achieved bone union with good clinical outcomes. Although there have been a few studies of intramedullary nail fixation in proximal tibia osteotomies, this is the first report of intramedullary nail fixation with DTOO.17,18
The use of intramedullary nail fixation was found to effectively preserve the soft tissue above the osteotomy site. Our method did not cause circulatory disturbances sometimes observed with procedures such as locking plates, even in osteotomy sites with large openings, and the possibility of pin site infection that can occur with external fixation was eliminated. Complications are frequent when plate and circular external fixators are used. Harada et al. reported a case series of 20 corrective osteotomies for posttraumatic OA of the ankle. In all five cases where the osteotomized bone was fixed with a locking compression plate, screws, or K-wires, the hardware was removed at the patient’s request because of symptoms caused by local irritation. Moreover, all of the remaining 15 cases, in which the osteotomized bone was fixed with a circular external fixator, developed pin site infections. 11 Fixation with an intramedullary nail reduces the likelihood of these complications. It also has advantages over other fixation methods for patients’ postoperative weight bearing. When a circular external fixator is used, partial weight bearing is allowed 6–8 weeks after surgery, with a subsequent gradual increase to the load. 11 Using intramedullary nail fixation, we were able to allow partial weight bearing 3 weeks postoperatively and full weight bearing at 6 weeks. Additionally, circular external fixators are removed 3–4 months after surgery, once bone union is achieved. 11 This is not necessary with our approach. Intramedullary nail fixation for DTOO provides sufficient correction and stability without the weaknesses of ring-type extramedullary fixation and plate fixation.
Medial application of standard large fragment plates has historically been associated with high rates of wound necrosis and infection.19–22 Distal lower leg fractures are caused by high-impact traumas such as falling from a height or low-impact traumas such as falls in the elderly. Soft tissue complications are common because of soft tissue damage during injury and surgery. McFerran et al. evaluated the complications encountered in the treatment of plafond fractures and found a local complication rate of 54%, comprising wound breakdown, deep soft tissue infection/osteomyelitis, and superficial wound infections. 7 Ovadia et al. reported that 16 of 142 patients required soft tissue procedures for wound closure. 8 Medial plate fixation in cases with fragile soft tissue can easily lead to a range of complications. Even with plate fixation to the tibia from the anterolateral side, such complications may still occur. Another study found that six of 42 (15%) patients treated using anterolateral locking plates had soft tissue complications, including marginal skin necrosis and infection. 23
In DTOO with large openings at the osteotomy site, the soft tissue of the distal tibia is fragile, and fixation of the osteotomy with a plate would likely lead to soft tissue complications. Thus, we used intramedullary nails to fix these osteotomy sites. Im et al. compared the use of closed intramedullary nailing and open reduction and internal fixation with anatomic plates in distal metaphyseal fractures of the tibia and found a lesser incidence of superficial infection with closed intramedullary nailing than fixation with anatomic plates. 12 Seyhan et al., also compared percutaneous locked plate treatment and intramedullary nail treatment for distal tibial fractures. The rate of both deep and superficial infections was higher with percutaneous locked plates than with intramedullary nails. 24 These studies support our findings and further demonstrate the superiority of intramedullary nails over plates for the fixation of osteotomy sites with large opening angles. Moreover, recent advances in the design of these nails, which now have interlocking holes close to the tip enable the placement of at least three screws in the distal fragment, preventing secondary malalignment. Three distal interlocking holes 25–30 mm from the nail tip are common in current tibial nails, and distal interlocking hole positioning in different planes has biomechanical advantages. The rotational stability of the construct increases the further the distal interlocking screw is from the fracture. 25
In the present study, intramedullary nail fixation for DTOO achieved good clinical results. A suprapatellar approach has the advantage to confirm the correction angle during the insertion of the intramedullary nail because it can be inserted with the knee extension. Any approach that allows the insertion of an intramedullary nail with the knee in extension can provide this advantage. Among various approaches to inserting an intramedullary nail, an intramedullary nail can be inserted at the center of the tibia and its entry point can be well controlled through the suprapatellar approach compared to other approaches such as the sub-patellar approach. However, there are a couple of issues with this technique. First, the suprapatellar approach requires additional invasion around the knee joint. Second, this method cannot be applied after knee arthroplasty. Nevertheless, the advantages of intramedullary nail fixation over locking plates or external fixators greatly outweigh these minor disadvantages.
This study had several limitations. First, the number of patients is small, and DTOO was performed on various grades ranging from 3a to 4 in the Takakura–Tanaka classification. Second, clinical outcomes with only short-term follow-up “periods” were described Clinical outcomes should be evaluated by a long-term follow-up. Finally, this was a retrospective study. Since this study demonstrated short-term clinical outcomes, the long-term outcomes remain unclear. However, the most important concern for this procedure are complications relating to skin breakdown and bone union, and short-term follow-up is sufficient to evaluate these concerns. Although good clinical outcomes in short-term follow-up were obtained in this procedure, prospective randomized control trials with a long-term follow-up will be needed. Ideally, these should compare the use of intramedullary nail fixation with plate fixation and/or external fixation in DTOO to fully assess the effectiveness of this method.
Conclusion
Our study showed that intramedullary nail fixation of the osteotomy site in DTOO effectively avoids soft tissue complications such as wound necrosis and demonstrates no correction loss even with large opening osteotomy sites.
Footnotes
Acknowledgements
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Ethical approval
This research has been approved by the IRB of the authors’ affiliated institutions. Verbal informed consent was obtained from the participants. All study procedures were conducted in accordance with principles of the 1964 Declaration of Helsinki.
IRB approval
This study was approved by institutional review board at Juntendo shizuoka hospital, 19.438; approval number: 721; approval date: 10/Feb/2020.
