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Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using three-dimensional surgical computer simulation and patient-matched instrument
Journal of Orthopaedic Science xxx (xxxx) xxx
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Original Article
Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using three-dimensional surgical computer simulation and patient-matched instrument Kunihiro Oka, Atsuo Shigi, Hiroyuki Tanaka, Hisao Moritomo, Sayuri Arimitsu, Tsuyoshi Murase* Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, 2-2, Yamada-oka, Suita, Osaka, 565-0871, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 22 August 2019 Received in revised form 12 October 2019 Accepted 11 November 2019 Available online xxx
Background: Corrective osteotomy of malunited intra-articular distal radius fracture is challenging. In this study, we investigated the results in patients with malunited intra-articular distal radius fracture who underwent intra-articular corrective osteotomy through an extra-articular approach using threedimensional (3-D) computer simulation and a patient-matched instrument (PMI). Methods: We retrospectively studied five consecutive patients with symptomatic malunited intraarticular distal radius fracture who underwent corrective osteotomy using a PMI. The maximal stepoff on computed tomography and the deformity angle on plain radiographs were evaluated. The clinical examination parameters included range of motion (ROM), grip strength, pain according to visual analog scale (VAS), and Patient-Rated Wrist Evaluation (PRWE) score. Results: The maximal step-off was significantly reduced from 4.9 ± 1.8 to 1.0 ± 0.2 mm (p ¼ 0.008). The absolute differences between the affected side and the normal contralateral side in radial inclination were significantly reduced from 5.4 ± 3.4 e1.2 ± 1.1 (p ¼ 0.043). These differences were not significantly reduced postoperatively in the volar tilt and ulnar variance. VAS was significantly reduced from 4.1 ± 1.6 to 0.9 ± 0.7 cm (p ¼ 0.006). The PRWE score significantly improved from 41.6 ± 22.0 to 15.7 ± 19.5 (p ¼ 0.043). Grip strength was significantly increased from 54.0% ± 14.8%e85.8% ± 18.8% (p ¼ 0.003). The preoperative and postoperative total arc of the wrist and forearm ROM were not significantly different. Conclusions: Intra-articular corrective osteotomy using PMI could be one of the reliable treatment options for intra-articular malunion. PMI has exceptionally high precision performance, and it is also anticipated to yield superior surgical results. © 2019 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.
1. Introduction Distal radius fracture is among the most common injuries. Anatomical reduction is the key to the recovery of wrist function [1]. Residual deformities may cause wrist dysfunction, such as pain, restriction of range of motion (ROM), and decreased grip strength [2e4]. Extra-articular malunion of the distal radius is treated with corrective osteotomy to recover wrist function [5e7]. For intraarticular malunion, a salvage procedure, such as partial wrist arthrodesis, is sometimes indicated to reduce wrist pain, although
* Corresponding author. Fax: þ81 6 6879 3559. E-mail address: [email protected] (T. Murase).
it may lead to loss of motion as corrective osteotomy is technically difficult to perform [8e10]. Several investigators have reported favorable results from intraarticular corrective osteotomy for symptomatic intra-articular malunion with or without arthroscopic assistance [9,11e14]. However, dissection of the joint capsule and ligament to perform osteotomy with direct view of the articular surface may result in postoperative joint stiffness. Detachment of soft tissue from the malunited fragment poses a risk of osteonecrosis [14]. Less-invasive arthroscopic procedures also require considerable surgical skills to accomplish an appropriate intra-articular corrective osteotomy. Accordingly, three-dimensional (3-D) intra-articular corrective osteotomy through an extra-articular approach without arthrotomy, using a surgical guide designed from preoperative computer
https://doi.org/10.1016/j.jos.2019.11.005 0949-2658/© 2019 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx
simulation, has been developed [15,16]. Although these novel techniques make it possible to perform intra-articular corrective osteotomy adequately, few reports have described the clinical outcomes. Here we investigated five patients with malunited intraarticular distal radius fracture who underwent corrective osteotomy performed using a patient-matched instrument (PMI) designed and manufactured based on preoperative 3-D computer simulation. 2. Materials and methods 2.1. Patients This is a retrospective case-series study on the surgical outcome of intra-articular corrective osteotomy for distal radius malunion using preoperative computer simulation and a PMI. This study was approved by the institutional review board of our institution and followed the tenets of the Declaration of Helsinki (as revised in 2000). Each author certifies that his or her institution approved the human protocol, so that all investigations were conducted in conformity with the ethical principles of research. Moreover, informed consent for publication of data from the cases was obtained from all study participants. From May 2004 to June 2017, five consecutive patients with intra-articular distal radius malunion, treated with intra-articular corrective osteotomy using a PMI, participated in the investigation. All patients were male (aged 33e76 years, average 44.4 years at the time of surgery). The inclusion criterion of this surgery was the presence of intra-articular deformity after distal radius fracture on the articular surface of the distal radius with more than 2 mm or greater step-off [9], accompanied by functional disabilities, such as restricted wrist ROM and pain. We excluded patients aged <18 years or with progressive osteoarthritis of the radiocarpal joint, rheumatoid arthritis, other inflammatory pathologies, or bilateral deformity of the distal radius. The initial treatment of the radial fracture was conservative therapy with cast immobilization for three patients because the step-off was within 2 mm at the initial diagnosis. One patient underwent open reduction and internal fixation with volar locking plate. The remaining one patient was a case that missed the fracture. The original fracture was the volar Barton type in four patients and the dorsal diepunch type in one patient. All patients reported having restriction of wrist ROM accompanied by severe pain. The average duration from initial injury to corrective osteotomy was 9.0 months (range, 6e12 months). The follow-up time was at least 16 months for all patients. The patients’ backgrounds are described in Table 1.
radiation-dose technique (scan time 0.5 s, slice thickness 0.625 mm, 10 mA, 120 kV) [17]. 3-D computer models of the bilateral forearms were constructed from CT data and analyzed using commercially available software (BoneViewer™ and BoneSimulator™, Orthree, Osaka, Japan). We evaluated the amount of intra-articular deformity of step-off by matching the affected radius to the mirror image of the normal contralateral radius. The malunited fragment was separated along the original fracture line and was reduced to create a smooth articular surface. We designed the PMI so that preoperative simulation was reproduced during actual surgery. The PMI was manufactured as a plastic model made of medical-grade resin (United States Pharmacopeia class VI), which had passed the tests for cytotoxicity, dermal irritation, and delayedtype hypersensitivity, with rapid prototyping technology through a 3-D printer (Formiga P, EOS GmbH Electro Systems, Krailling, Germany or Eden250, Objet Geometries, Rehovot, Israel). The PMI was shaped to exactly fit onto the bone surface of the distal radius and had multiple drilling sleeves to divide the malunited fragment from the radius through an extra-articular approach. 2.3. Surgical procedures The bone surface of the distal radius was exposed through a volar approach for malunion of the volar fragment and a dorsal approach for malunion of the dorsal fragment. The PMI was fitted to the bone surface of the distal radius, and placement was confirmed by inserting a reference Kirschner wire (K-wire) through the guide pointing to the tip of the radial styloid. The accuracy of the PMI location on the distal radius has been corroborated with a freshfrozen cadaveric study in which errors of corrective osteotomy were <1.0 and 1.0 mm [18]. Multiple drilling holes were made through drill sleeves on the PMI and the osteotomy was completed along the drilling holes. The fragment was carefully relocated to reduce the step-off on the articular surface under arthroscopic visualization and/or X-ray image intensifier. After reduction, the fragment was fixed with double-thread screws for one volar Barton type fracture, with a volar locking plate for three volar Barton type fractures, and with both double-thread screws and dorsal locking plate for one dorsal die-punch type fracture. The five operations were performed by different certified hand surgeons with sufficient experience. The surgical time of each patient was described in Table 1. Cast immobilization was maintained for 2 weeks postoperatively. After removal of the plaster, the patient was encouraged to perform active exercises of the wrist and forearm under the supervision of a physiotherapist. 2.4. Representative case
2.2. Computer simulation and manufacturing of the PMI To plan corrective surgery for intra-articular deformity of the distal radius, we attempted to simulate 3-D correction of the deformity using computer models of the bones. Forearms of the patient were scanned with computed tomography (CT) using a low-
Case 2: A 34-year-old man had a malunion of a volar Barton fracture with an intra-articular step-off of 4.6 mm (Fig. 1aec). The deformity was evaluated using 3-D bone models, and the intraarticular corrective osteotomy along the original fracture line was simulated (Fig. 2a and b). The PMI fitting on the volar surface of
Table 1 Each patient's data. Patient
Affected side
Gender
Age (years)
Interval from injury to surgery (months)
Initial treatment
Type of fracture
Value of step-off (mm)
Surgical time (minutes)
1 2 3 4 5 Average
L R R L L
M M M M M
33 34 41 38 76 44.4
10 10 12 7 6 9.0
ORIF Cast Cast Cast Ignored
VB VB DD VB VB
4.5 4.6 3.0 7.8 4.5 4.9
165 223 225 262 238 227
ORIF, open reduction and internal fixation; VB, volar Barton; DD, dorsal die punch.
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx
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Fig. 1. Anteroposterior (a) and lateral (b) preoperative plain radiographs and sagittal plane of computed tomography (c) show subduction of the lunate fossa.
distal radius was designed and manufactured accordingly (Fig. 3aec). The volar surface of the distal radius was exposed through a volar approach, and the PMI was fit on the bone surface manually. The placement was confirmed by inserting a reference 1.2-mm K-wire (Figs. 3a and 4a). Then, the PMI was fixed to the radius with two 2.0-mm K-wires (Figs. 3b and 4b). Multiple drilling holes were made by passing 1.0-mm K-wires through drill sleeves on the PMI while confirming penetration of their ends to the original articular fracture line under arthroscopic visualization (Fig. 4c). After removal of the PMI, the malunited fragment was divided with a bone chisel along the multiple drilling holes. The fragment was completely separated from the radius along with soft tissues, such as the radiocarpal ligaments and capsule (Fig. 5a). The fragment was moved distally to reduce the intra-articular step-off and fixed temporally with 1.2-mm K-wires (Fig. 5b). Finally, the fragment was fixed rigidly with a volar locking plate in the correct position (Fig. 6aec). Case 4: A 38-year-old man had a volar Barton fracture, resulting in malunion with step-off of 7.8 mm (Fig. 7aed). The 3-D corrective osteotomy was performed using a PMI and a fixation was performed with a volar locking plate (Fig. 8aed).
Fig. 2. (a) The affected radius (blue) was superimposed over the mirror model of the contralateral normal radius (translucent white). (b) The malunited fragment (pink) was divided and reduced to the normal position. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
2.5. Measurements All patients were clinically and radiographically evaluated preoperatively and during the final follow-up period. The union was
Fig. 3. (a) The position of patient-matched instrument (PMI) was confirmed with a reference K-wire (*) penetrating the radial styloid. (b) The PMI was fixed with two K-wires (**). (c) Multiple drilling holes were made and the malunited fragment (pink) was divided. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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Fig. 4. (a, b) The position of patient-matched instrument was confirmed using a K-wire (*) and fixed. (c) Arthroscopic image showed the penetration of K-wire to the original articular fracture line. Shaded area surrounded black dotted line indicates the step-off.
Fig. 5. (a) The malunited fragment was observed to be connected with the capsule (y). The area surrounded by white dotted lines and white arrow indicates osteotomy surfaces and radiocarpal joint. (b) The fragment was reduced and fixed temporarily with K-wires.
considered complete when the osteotomy line disappeared on plain radiographs. Volar tilt (VT), radial inclination (RI), and ulnar variance (UV) were determined from the radiographs, and the absolute differences between the affected side and normal contralateral side were recorded. The degree of osteoarthritis (OA) was evaluated as grades 0 to 3 with preoperative and final follow-up anteroposterior plain radiographs according to Knirk and Jupiter's classification (grade 0, normal; grade 1, slight joint-space narrowing; grade 2, marked joint-space narrowing and osteophyte formation; grade 3, bone-on-bone, osteophyte formation, and cyst formation) [4]. The maximal step-off of the articular surface was measured using the sagittal or coronal slices of preoperative and postoperative CT scan via commercially available software (Synapse Ex-5, FUJIFILM Corporation, Tokyo, Japan) according to the method reported by Cole et al. (Fig. 9) [19]. The patients were clinically assessed for pain, wrist and forearm ROM, grip strength, and postoperative complications. The PatientRated Wrist Evaluation (PRWE) score was used to assess patientreported outcomes. We used a visual analog scale (VAS) to assess pain, determined by measuring the distance (in centimeters) on a
10.0-cm line between 0 (no pain) and patient's mark. The minimal clinically important difference (MCID) was reported to be 3.0 for VAS [20] and 14 for PRWE [21]. Therefore, we confirmed that there was improvement in VAS and PRWE, when they showed values of 3.0 and 14, respectively, with the present treatment using PMI. Grip strength was recorded as a percentage of that on the normal contralateral side. 2.6. Statistical analysis A priori power analysis performed prior to the beginning of data collection revealed that a sample size of four cases would provide a power of 80%, which would be sufficient to detect a 3 mm (clinically unacceptable value) reduction in step-off of the articular surface in CT evaluation at the 0.05 confidence level. The normality of all the variables in any analysis was tested using the ShapiroeWilk tests. Data are expressed as means and standard deviation of the means. The differences in the values between the preoperative and postoperative parameters were analyzed using the paired t-test (if paired differences were normally distributed) or Wilcoxon signed-
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx
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Fig. 6. The fragment was rigidly fixed with the volar locking plate. Anteroposterior (a) and lateral (b) postoperative plain radiographs and sagittal plane of computed tomography (c) show the smooth articular surface of the distal radius.
Fig. 7. Anteroposterior (a) and lateral (b) preoperative plain radiographs and sagittal plane of computed tomography (c) show malunion of intra-articular fracture. The range of wrist flexion (*) was restricted (d).
Fig. 8. Anteroposterior (a) and lateral (b) postoperative plain radiographs show that the malunited fragment was reduced. The step-off was completely reduced in the sagittal plane of computed tomography (c). The range of wrist flexion (*) was improved postoperatively (d).
rank test (if paired differences were non-normally distributed). Significance was established at p < 0.05. Statistical analyses were performed with IBM SPSS, Version 25.0 (IBM, Armonk, NY, USA). 3. Results The average follow-up period was 48.5 months (range, 16e142 months). The step-off of the articular surface was reduced, and wrist function was recovered in all patients. Bone union was achieved at a mean of 9 weeks (range, 4e15 weeks) postoperatively.
The maximal step-off was significantly reduced (p ¼ 0.008). Although the preoperative absolute differences in VT and UV between the affected side and normal contralateral side were not significantly different from postoperative values (p ¼ 0.191 and p ¼ 0.109), the difference in RI significantly improved (p ¼ 0.043). Four patients had no progress in their OA grade. The remaining one patient with grade 1 OA progressed to grade 2 OA at the final follow-up (Table 2). VAS and PRWE were significantly improved (p ¼ 0.006 and p ¼ 0.043). Four of the five patients showed improvement in VAS greater than the MCID value (3.0); all five
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx Table 3 Clinical assessment. Assessment
Before Surgery
After Surgery
P value
Wrist ROM Forearm ROM Grip strengtha, % VAS, cm PRWE
93 ± 41 144 ± 38 54.0 ± 14.8 4.1 ± 1.6 41.6 ± 22.0
146 ± 23 164 ± 13 85.8 ± 18.8 0.9 ± 0.7 15.7 ± 19.5
0.085b 0.240b *0.003b *0.006b *0.043c
ROM, range of motion; VAS, visual analog scale; PRWE, the patient-rated wrist evaluation. P values are statistically significant (*P < 0.05). a Percentage of the contralateral limb. b Indicates p value from paired t-test. c Indicates p value from Wilcoxon signed-rank test.
Fig. 9. B is the displaced position of the fracture from A. C is intersection of the approximate circle on the articular surface and a line connecting the center of this circle and B. The distance CB is defined as the step-off.
patients showed improvement in PRWE greater than the MCID value (14). Moreover, grip strength significantly increased (p ¼ 0.003). The preoperative and postoperative total arc of the wrist and forearm ROM were not significantly different (p ¼ 0.085 and p ¼ 0.240) (Table 3). There were no major complications related to the surgery.
4. Discussion Intra-articular malunion of the distal radius is one of the major complications after distal radius fracture [4]. Residual intraarticular deformity of more than 2 mm results in poor wrist function. Reducing the step-off of the articular surface is considered the optimal treatment to recover wrist function. However, correction of the intra-articular malunited fragment without capsule release requires advanced arthroscopic skills and special tools, such as the osteotome and arthroscopic guide, for inside-out intra-articular osteotomy [11]. The salvage procedure of radiocarpal arthrodesis is one of the treatments for relief of wrist pain, although decrease in wrist ROM is inevitable. The total arc of wrist ROM after partial wrist arthrodesis for posttraumatic wrist OA was 49 e98 [8,22e24]. Intra-articular corrective osteotomy using various approaches, such as direct view with arthrotomy [14], fluoroscopic guidance, arthroscopic assistance [11], and patient-specific drill guide [16], has been reported to result in postoperative wrist ROM Table 2 Radiographic assesment. Assessment
Before Surgery
After Surgery
P value
Step-off, mm VTa RIa UVa, mm Osteoarthritis
4.9 ± 1.8 7.0 ± 6.0 5.4 ± 3.4 2.4 ± 2.4 G0: 0, G1: 3, G2: 2, G3: 0
1.0 ± 0.2 2.8 ± 1.3 1.2 ± 1.1 0.4 ± 0.5 G0: 0, G1: 2, G2: 3, G3: 0
*0.008b 0.191b *0.043c 0.109c e
VT, volar tilt; RI, radial inclination; UV, ulnar variance. G0-3: grade0-3. P values are statistically significant (*P < 0.05). a Difference to the contralateral side. b Indicates p value from paired t-test. c Indicates p value from Wilcoxon signed-rank test.
ranging from 112 to 145 , which is superior to the results of partial arthrodesis. However, intra-articular osteotomy is technically demanding and has a risk of bone necrosis of separated fragments by the release of soft tissues attached to them and postoperative joint stiffness. Therefore, we attempted to develop a 3-D computer simulation system and PMIs to enable intra-articular corrective osteotomy for intra-articular malunion of the distal radius without damage to the capsule and radiocarpal ligaments. We have reported reliable use of these novel technologies for long bone deformity in the upper extremity [25,26] and described the first case of intra-articular malunion of the distal radius treated with a PMI through an extra-articular approach [15]. Schweizer et al. [16] reported six case series treated by a palmar, dorsal, or combined approach with corrections of multiple fragments using PMIs. They also quantitatively evaluated the intra-articular correction of stepoff using preoperative and postoperative 3-D CT models and reported accurate correction and good clinical results. We also quantitatively evaluated the reduction of intra-articular step-off using preoperative and postoperative CT scans. Additionally, we investigated clinical findings, including patient-reported outcomes (VAS and PRWE). PMIs provided highly accurate reduction with an average residual step-off of 1.0 ± 0.2 mm, similar to the results of Schweizer et al. [16] RI also significantly improved. Although the absolute differences in VT and UV between the affected side and normal contralateral side were statistically insignificant, the postoperative values of 2.8 ± 1.3 and 0.4 ± 0.5 mm were clinically accepted. The VAS score for wrist pain improved beyond the MCID in four of five patients. PRWE improved beyond the MCID in all five patients. One patient (case 4) whose OA proceeded from grade 1 to 2 had a deformity of step-off with 7.8 mm. The degree of preoperative deformity would affect the progression of OA, despite being corrected to 1.1 mm postoperatively. As for the PMI, we added the reference guide on it through which the K-wire could point to the anatomical landmark of the distal radius for the confirmation of position because PMI placement directly affects the accuracy of osteotomy. This refinement would improve the reliability of the PMI. Intra-articular corrective osteotomy through the extra-articular approach using the PMI designed based on preoperative 3-D simulation achieved accurate correction of intra-articular deformity and provided good postoperative results, including patientreported outcomes, independently of the surgeon's skill. The limitations of our investigation include the small number of cases and the several different fracture types. Although a larger number of participants might have resulted in different findings, the a priori power analysis and a sample size of four patients had a statistically high power of >80% for the step-off in the post hoc power analysis (p ¼ 0.05). The lack of a control group was also a major limitation. Prospective randomized controlled trial is required to prove the utility of a PMI for intra-articular corrective
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx
osteotomy [27]. Because different surgeons performed the corrective osteotomies, the clinical results may have been influenced by surgical skill. However, the specialized hand surgeons had more than 10 years of experience each, and therefore, the effect of surgical skill on the results was likely minor. Variations in the treatment strategy (volar or dorsal approach) may also have affected the surgical results. However, including variations of intra-articular malunion in the same group of intra-articular step-off deformity is acceptable, considering the degree of intra-articular step-off mostly affects the wrist function. CT of the wrist was preoperatively and postoperatively performed in this study to evaluate the stepoff, which highlights radiation exposure in patients. However, our CT protocol reduced the radiation exposure to <1/10 under normal conditions of CT parameters [17]. Measurement of the deformity is necessary to evaluate the present procedure. Finally, time and expense are required for computer simulation and manufacturing of the PMI. Computer simulation takes approximately 3 h. The cost of manufacturing the PMI is US$1500 to US$2000 in Japan but may vary depending on the situation. Our results indicate adequate reliability of these technologies. Although there are some limitations, we believe that 3-D preoperative simulation and intra-articular osteotomy using a PMI could be reliable treatment options for intra-articular malunion. In particular, PMI is useful for intra-articular malunion once bone union is completed and where the original fracture line cannot be identified during surgery before osteoarthritis progression. The PMI not only has exceptionally high precision performance but is also anticipated to yield superior surgical results, regardless of the surgeon's skill. Declaration of Competing Interest Tsuyoshi Murase and Kunihiro Oka received funding in support of this research from the Japan Society for the Promotion of Science. Tsuyoshi Murase receives research support from Teijin Nakashima Medical Co., LTD., during of the study. Tsuyoshi Murase and Oka owns stocks of Orthree Co. LTD. The other authors declare that there is no conflict of interest. Acknowledgments This work was supported by the Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science, Grant Number JP 18K12104 and 19H03783. References [1] Gehrmann SV, Windolf J, Kaufmann RA. Distal radius fracture management in elderly patients: a literature review. J Hand Surg Am 2008 Mar;33(3):421e9. [2] Ali M, Brogren E, Wagner P, Atroshi I. Association between distal radial fracture malunion and patient-reported activity limitations: a long-term followup. J Bone Joint Surg Am 2018 Apr 18;100(8):633e9. [3] Jupiter JB. Complex articular fractures of the distal radius: classification and management. J Am Acad Orthop Surg 1997 May;5(3):119e29. [4] Knirk JL, Jupiter JB. Intra-articular fractures of the distal end of the radius in young adults. J Bone Joint Surg Am 1986 Jun;68(5):647e59. € rensen A, [5] Buijze GA, Leong NL, Stockmans F, Axelsson P, Moreno R, Ibsen So Jupiter JB. Three-dimensional compared with two-dimensional preoperative planning of corrective osteotomy for extra-articular distal radial malunion: a multicenter randomized controlled trial. J Bone Joint Surg Am 2018 Jul 18;100(14):1191e202.
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n SA, Brouwer KM, Doornberg JN, Goslings JC, Kloen P, [6] Lozano-Caldero Jupiter JB. Long-term outcomes of corrective osteotomy for the treatment of distal radius malunion. J Hand Surg Eur 2010 Jun;35(5):370e80. [7] Miyake J, Murase T, Moritomo H, Sugamoto K, Yoshikawa H. Distal radius osteotomy with volar locking plates based on computer simulation. Clin Orthop Relat Res 2011 Jun;469(6):1766e73. [8] Bain GI, Ondimu P, Hallam P, Ashwood N. Radioscapholunate arthrodesis - a prospective study. Hand Surg 2009;14(2e3):73e82. [9] Buijze GA, Prommersberger KJ, Gonz alez Del Pino J, Fernandez DL, Jupiter JB. Corrective osteotomy for combined intra- and extra-articular distal radius malunion. J Hand Surg Am 2012 Oct;37(10):2041e9. [10] Nagy L. Salvage of post-traumatic arthritis following distal radius fracture. Hand Clin 2005 Aug;21(3):489e98. [11] del Pinal F, Garcia-Bernal FJ, Delgado J, Sanmartín M, Regalado J, Cerezal L. Correction of malunited intra-articular distal radius fractures with an inside-out osteotomy technique. J Hand Surg Am 2006 Jul-Aug;31(6): 1029e34. [12] Gobel F, Vardakas DG, Riano F, Vogt MT, Sarris I, Sotereanos DG. Arthroscopically assisted intra-articular corrective osteotomy of a malunion of the distal radius. Am J Orthoped 2004 Jun;33(6):275e7. [13] Marx RG, Axelrod TS. Intraarticular osteotomy of distal radial malunions. Clin Orthop Relat Res 1996 Jun;(327):152e7. [14] Ring D, Prommersberger KJ, Gonzalez del Pino J, Capomassi M, Slullitel M, Jupiter JB. Corrective osteotomy for intra-articular malunion of the distal part of the radius. J Bone Joint Surg Am 2005 Jul;87(7):1503e9. [15] Oka K, Moritomo H, Goto A, Sugamoto K, Yoshikawa H, Murase T. Corrective osteotomy for malunited intra-articular fracture of the distal radius using a custom-made surgical guide based on three-dimensional computer simulation: case report. J Hand Surg Am 2008 Jul-Aug;33(6):835e40. [16] Schweizer A, Furnstahl P, Nagy L. Three-dimensional correction of distal radius intra-articular malunions using patient-specific drill guides. J Hand Surg Am 2013 Dec;38(12):2339e47. [17] Oka K, Murase T, Moritomo H, Goto A, Sugamoto K, Yoshikawa H. Accuracy analysis of three-dimensional bone surface models of the forearm constructed from multidetector computed tomography data. Int J Med Robot 2009 Dec;5(4):452e7. [18] Omori S, Murase T, Kataoka T, Kawanishi Y, Oura K, Miyake J, Tanaka H, Yoshikawa H. Three-dimensional corrective osteotomy using a patientspecific osteotomy guide and bone plate based on a computer simulation system: accuracy analysis in a cadaver study. Int J Med Robot 2014 Jun;10(2): 196e202. [19] Cole RJ, Bindra RR, Evanoff BA, Gilula LA, Yamaguchi K, Gelberman RH. Radiographic evaluation of osseous displacement following intra-articular fractures of the distal radius: reliability of plain radiography versus computed tomography. J Hand Surg Am 1997 Sep;22(5):792e800. [20] Lee JS, Hobden E, Stiell IG, Wells GA. Clinically important change in the visual analog scale after adequate pain control. Acad Emerg Med 2003 Oct;10(10): 1128e30. [21] Sorensen AA, Howard D, Tan WH, Ketchersid J, Calfee RP. Minimal clinically important differences of 3 patient-rated outcomes instruments. J Hand Surg Am 2013 Apr;38(4):641e9. [22] Garcia-Elias M, Lluch A, Ferreres A, Papini-Zorli I, Rahimtoola ZO. Treatment of radiocarpal degenerative osteoarthritis by radioscapholunate arthrodesis and distal scaphoidectomy. J Hand Surg Am 2005 Jan;30(1):8e15. € w S, Prommersberger KJ, van [23] Muhldorfer-Fodor M, Ha HP, Hohendorff B, Lo Schoonhoven J. Results after radioscapholunate arthrodesis with or without resection of the distal scaphoid pole. J Hand Surg Am 2012 Nov;37(11): 2233e9. [24] Quadlbauer S, Leixnering M, Jurkowitsch J, Hausner T, Pezzei C. Volar radioscapholunate arthrodesis and distal scaphoidectomy after malunited distal radius fractures. J Hand Surg Am 2017 Sep;42(9). 754.e1-754.e8. [25] Murase T, Oka K, Moritomo H, Goto A, Yoshikawa H, Sugamoto K. Threedimensional corrective osteotomy of malunited fractures of the upper extremity with use of a computer simulation system. J Bone Joint Surg Am 2008 Nov;90(11):2375e89. [26] Oka K, Tanaka H, Okada K, Sahara W, Myoui A, Yamada T, Yamamoto M, Kurimoto S, Hirata H, Murase T. Three-dimensional corrective osteotomy for malunited fractures of the upper extremity using patient-matched instruments: a prospective, multicenter, open-label, single-arm trial. J Bone Joint Surg Am 2019 Apr 17;101(8):710e21. [27] Leong NL, Buijze GA, Fu EC, Stockmans F, Jupiter JB. Distal Radius Malunion (DiRaM) collaborative group. Computer-assisted versus non-computerassisted preoperative planning of corrective osteotomy for extra-articular distal radius malunions: a randomized controlled trial. BMC Muscoskelet Disord 2010 Dec 14;11:282.
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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Original Article
Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using three-dimensional surgical computer simulation and patient-matched instrument Kunihiro Oka, Atsuo Shigi, Hiroyuki Tanaka, Hisao Moritomo, Sayuri Arimitsu, Tsuyoshi Murase* Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, 2-2, Yamada-oka, Suita, Osaka, 565-0871, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 22 August 2019 Received in revised form 12 October 2019 Accepted 11 November 2019 Available online xxx
Background: Corrective osteotomy of malunited intra-articular distal radius fracture is challenging. In this study, we investigated the results in patients with malunited intra-articular distal radius fracture who underwent intra-articular corrective osteotomy through an extra-articular approach using threedimensional (3-D) computer simulation and a patient-matched instrument (PMI). Methods: We retrospectively studied five consecutive patients with symptomatic malunited intraarticular distal radius fracture who underwent corrective osteotomy using a PMI. The maximal stepoff on computed tomography and the deformity angle on plain radiographs were evaluated. The clinical examination parameters included range of motion (ROM), grip strength, pain according to visual analog scale (VAS), and Patient-Rated Wrist Evaluation (PRWE) score. Results: The maximal step-off was significantly reduced from 4.9 ± 1.8 to 1.0 ± 0.2 mm (p ¼ 0.008). The absolute differences between the affected side and the normal contralateral side in radial inclination were significantly reduced from 5.4 ± 3.4 e1.2 ± 1.1 (p ¼ 0.043). These differences were not significantly reduced postoperatively in the volar tilt and ulnar variance. VAS was significantly reduced from 4.1 ± 1.6 to 0.9 ± 0.7 cm (p ¼ 0.006). The PRWE score significantly improved from 41.6 ± 22.0 to 15.7 ± 19.5 (p ¼ 0.043). Grip strength was significantly increased from 54.0% ± 14.8%e85.8% ± 18.8% (p ¼ 0.003). The preoperative and postoperative total arc of the wrist and forearm ROM were not significantly different. Conclusions: Intra-articular corrective osteotomy using PMI could be one of the reliable treatment options for intra-articular malunion. PMI has exceptionally high precision performance, and it is also anticipated to yield superior surgical results. © 2019 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.
1. Introduction Distal radius fracture is among the most common injuries. Anatomical reduction is the key to the recovery of wrist function [1]. Residual deformities may cause wrist dysfunction, such as pain, restriction of range of motion (ROM), and decreased grip strength [2e4]. Extra-articular malunion of the distal radius is treated with corrective osteotomy to recover wrist function [5e7]. For intraarticular malunion, a salvage procedure, such as partial wrist arthrodesis, is sometimes indicated to reduce wrist pain, although
* Corresponding author. Fax: þ81 6 6879 3559. E-mail address: [email protected] (T. Murase).
it may lead to loss of motion as corrective osteotomy is technically difficult to perform [8e10]. Several investigators have reported favorable results from intraarticular corrective osteotomy for symptomatic intra-articular malunion with or without arthroscopic assistance [9,11e14]. However, dissection of the joint capsule and ligament to perform osteotomy with direct view of the articular surface may result in postoperative joint stiffness. Detachment of soft tissue from the malunited fragment poses a risk of osteonecrosis [14]. Less-invasive arthroscopic procedures also require considerable surgical skills to accomplish an appropriate intra-articular corrective osteotomy. Accordingly, three-dimensional (3-D) intra-articular corrective osteotomy through an extra-articular approach without arthrotomy, using a surgical guide designed from preoperative computer
https://doi.org/10.1016/j.jos.2019.11.005 0949-2658/© 2019 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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simulation, has been developed [15,16]. Although these novel techniques make it possible to perform intra-articular corrective osteotomy adequately, few reports have described the clinical outcomes. Here we investigated five patients with malunited intraarticular distal radius fracture who underwent corrective osteotomy performed using a patient-matched instrument (PMI) designed and manufactured based on preoperative 3-D computer simulation. 2. Materials and methods 2.1. Patients This is a retrospective case-series study on the surgical outcome of intra-articular corrective osteotomy for distal radius malunion using preoperative computer simulation and a PMI. This study was approved by the institutional review board of our institution and followed the tenets of the Declaration of Helsinki (as revised in 2000). Each author certifies that his or her institution approved the human protocol, so that all investigations were conducted in conformity with the ethical principles of research. Moreover, informed consent for publication of data from the cases was obtained from all study participants. From May 2004 to June 2017, five consecutive patients with intra-articular distal radius malunion, treated with intra-articular corrective osteotomy using a PMI, participated in the investigation. All patients were male (aged 33e76 years, average 44.4 years at the time of surgery). The inclusion criterion of this surgery was the presence of intra-articular deformity after distal radius fracture on the articular surface of the distal radius with more than 2 mm or greater step-off [9], accompanied by functional disabilities, such as restricted wrist ROM and pain. We excluded patients aged <18 years or with progressive osteoarthritis of the radiocarpal joint, rheumatoid arthritis, other inflammatory pathologies, or bilateral deformity of the distal radius. The initial treatment of the radial fracture was conservative therapy with cast immobilization for three patients because the step-off was within 2 mm at the initial diagnosis. One patient underwent open reduction and internal fixation with volar locking plate. The remaining one patient was a case that missed the fracture. The original fracture was the volar Barton type in four patients and the dorsal diepunch type in one patient. All patients reported having restriction of wrist ROM accompanied by severe pain. The average duration from initial injury to corrective osteotomy was 9.0 months (range, 6e12 months). The follow-up time was at least 16 months for all patients. The patients’ backgrounds are described in Table 1.
radiation-dose technique (scan time 0.5 s, slice thickness 0.625 mm, 10 mA, 120 kV) [17]. 3-D computer models of the bilateral forearms were constructed from CT data and analyzed using commercially available software (BoneViewer™ and BoneSimulator™, Orthree, Osaka, Japan). We evaluated the amount of intra-articular deformity of step-off by matching the affected radius to the mirror image of the normal contralateral radius. The malunited fragment was separated along the original fracture line and was reduced to create a smooth articular surface. We designed the PMI so that preoperative simulation was reproduced during actual surgery. The PMI was manufactured as a plastic model made of medical-grade resin (United States Pharmacopeia class VI), which had passed the tests for cytotoxicity, dermal irritation, and delayedtype hypersensitivity, with rapid prototyping technology through a 3-D printer (Formiga P, EOS GmbH Electro Systems, Krailling, Germany or Eden250, Objet Geometries, Rehovot, Israel). The PMI was shaped to exactly fit onto the bone surface of the distal radius and had multiple drilling sleeves to divide the malunited fragment from the radius through an extra-articular approach. 2.3. Surgical procedures The bone surface of the distal radius was exposed through a volar approach for malunion of the volar fragment and a dorsal approach for malunion of the dorsal fragment. The PMI was fitted to the bone surface of the distal radius, and placement was confirmed by inserting a reference Kirschner wire (K-wire) through the guide pointing to the tip of the radial styloid. The accuracy of the PMI location on the distal radius has been corroborated with a freshfrozen cadaveric study in which errors of corrective osteotomy were <1.0 and 1.0 mm [18]. Multiple drilling holes were made through drill sleeves on the PMI and the osteotomy was completed along the drilling holes. The fragment was carefully relocated to reduce the step-off on the articular surface under arthroscopic visualization and/or X-ray image intensifier. After reduction, the fragment was fixed with double-thread screws for one volar Barton type fracture, with a volar locking plate for three volar Barton type fractures, and with both double-thread screws and dorsal locking plate for one dorsal die-punch type fracture. The five operations were performed by different certified hand surgeons with sufficient experience. The surgical time of each patient was described in Table 1. Cast immobilization was maintained for 2 weeks postoperatively. After removal of the plaster, the patient was encouraged to perform active exercises of the wrist and forearm under the supervision of a physiotherapist. 2.4. Representative case
2.2. Computer simulation and manufacturing of the PMI To plan corrective surgery for intra-articular deformity of the distal radius, we attempted to simulate 3-D correction of the deformity using computer models of the bones. Forearms of the patient were scanned with computed tomography (CT) using a low-
Case 2: A 34-year-old man had a malunion of a volar Barton fracture with an intra-articular step-off of 4.6 mm (Fig. 1aec). The deformity was evaluated using 3-D bone models, and the intraarticular corrective osteotomy along the original fracture line was simulated (Fig. 2a and b). The PMI fitting on the volar surface of
Table 1 Each patient's data. Patient
Affected side
Gender
Age (years)
Interval from injury to surgery (months)
Initial treatment
Type of fracture
Value of step-off (mm)
Surgical time (minutes)
1 2 3 4 5 Average
L R R L L
M M M M M
33 34 41 38 76 44.4
10 10 12 7 6 9.0
ORIF Cast Cast Cast Ignored
VB VB DD VB VB
4.5 4.6 3.0 7.8 4.5 4.9
165 223 225 262 238 227
ORIF, open reduction and internal fixation; VB, volar Barton; DD, dorsal die punch.
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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Fig. 1. Anteroposterior (a) and lateral (b) preoperative plain radiographs and sagittal plane of computed tomography (c) show subduction of the lunate fossa.
distal radius was designed and manufactured accordingly (Fig. 3aec). The volar surface of the distal radius was exposed through a volar approach, and the PMI was fit on the bone surface manually. The placement was confirmed by inserting a reference 1.2-mm K-wire (Figs. 3a and 4a). Then, the PMI was fixed to the radius with two 2.0-mm K-wires (Figs. 3b and 4b). Multiple drilling holes were made by passing 1.0-mm K-wires through drill sleeves on the PMI while confirming penetration of their ends to the original articular fracture line under arthroscopic visualization (Fig. 4c). After removal of the PMI, the malunited fragment was divided with a bone chisel along the multiple drilling holes. The fragment was completely separated from the radius along with soft tissues, such as the radiocarpal ligaments and capsule (Fig. 5a). The fragment was moved distally to reduce the intra-articular step-off and fixed temporally with 1.2-mm K-wires (Fig. 5b). Finally, the fragment was fixed rigidly with a volar locking plate in the correct position (Fig. 6aec). Case 4: A 38-year-old man had a volar Barton fracture, resulting in malunion with step-off of 7.8 mm (Fig. 7aed). The 3-D corrective osteotomy was performed using a PMI and a fixation was performed with a volar locking plate (Fig. 8aed).
Fig. 2. (a) The affected radius (blue) was superimposed over the mirror model of the contralateral normal radius (translucent white). (b) The malunited fragment (pink) was divided and reduced to the normal position. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
2.5. Measurements All patients were clinically and radiographically evaluated preoperatively and during the final follow-up period. The union was
Fig. 3. (a) The position of patient-matched instrument (PMI) was confirmed with a reference K-wire (*) penetrating the radial styloid. (b) The PMI was fixed with two K-wires (**). (c) Multiple drilling holes were made and the malunited fragment (pink) was divided. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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Fig. 4. (a, b) The position of patient-matched instrument was confirmed using a K-wire (*) and fixed. (c) Arthroscopic image showed the penetration of K-wire to the original articular fracture line. Shaded area surrounded black dotted line indicates the step-off.
Fig. 5. (a) The malunited fragment was observed to be connected with the capsule (y). The area surrounded by white dotted lines and white arrow indicates osteotomy surfaces and radiocarpal joint. (b) The fragment was reduced and fixed temporarily with K-wires.
considered complete when the osteotomy line disappeared on plain radiographs. Volar tilt (VT), radial inclination (RI), and ulnar variance (UV) were determined from the radiographs, and the absolute differences between the affected side and normal contralateral side were recorded. The degree of osteoarthritis (OA) was evaluated as grades 0 to 3 with preoperative and final follow-up anteroposterior plain radiographs according to Knirk and Jupiter's classification (grade 0, normal; grade 1, slight joint-space narrowing; grade 2, marked joint-space narrowing and osteophyte formation; grade 3, bone-on-bone, osteophyte formation, and cyst formation) [4]. The maximal step-off of the articular surface was measured using the sagittal or coronal slices of preoperative and postoperative CT scan via commercially available software (Synapse Ex-5, FUJIFILM Corporation, Tokyo, Japan) according to the method reported by Cole et al. (Fig. 9) [19]. The patients were clinically assessed for pain, wrist and forearm ROM, grip strength, and postoperative complications. The PatientRated Wrist Evaluation (PRWE) score was used to assess patientreported outcomes. We used a visual analog scale (VAS) to assess pain, determined by measuring the distance (in centimeters) on a
10.0-cm line between 0 (no pain) and patient's mark. The minimal clinically important difference (MCID) was reported to be 3.0 for VAS [20] and 14 for PRWE [21]. Therefore, we confirmed that there was improvement in VAS and PRWE, when they showed values of 3.0 and 14, respectively, with the present treatment using PMI. Grip strength was recorded as a percentage of that on the normal contralateral side. 2.6. Statistical analysis A priori power analysis performed prior to the beginning of data collection revealed that a sample size of four cases would provide a power of 80%, which would be sufficient to detect a 3 mm (clinically unacceptable value) reduction in step-off of the articular surface in CT evaluation at the 0.05 confidence level. The normality of all the variables in any analysis was tested using the ShapiroeWilk tests. Data are expressed as means and standard deviation of the means. The differences in the values between the preoperative and postoperative parameters were analyzed using the paired t-test (if paired differences were normally distributed) or Wilcoxon signed-
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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Fig. 6. The fragment was rigidly fixed with the volar locking plate. Anteroposterior (a) and lateral (b) postoperative plain radiographs and sagittal plane of computed tomography (c) show the smooth articular surface of the distal radius.
Fig. 7. Anteroposterior (a) and lateral (b) preoperative plain radiographs and sagittal plane of computed tomography (c) show malunion of intra-articular fracture. The range of wrist flexion (*) was restricted (d).
Fig. 8. Anteroposterior (a) and lateral (b) postoperative plain radiographs show that the malunited fragment was reduced. The step-off was completely reduced in the sagittal plane of computed tomography (c). The range of wrist flexion (*) was improved postoperatively (d).
rank test (if paired differences were non-normally distributed). Significance was established at p < 0.05. Statistical analyses were performed with IBM SPSS, Version 25.0 (IBM, Armonk, NY, USA). 3. Results The average follow-up period was 48.5 months (range, 16e142 months). The step-off of the articular surface was reduced, and wrist function was recovered in all patients. Bone union was achieved at a mean of 9 weeks (range, 4e15 weeks) postoperatively.
The maximal step-off was significantly reduced (p ¼ 0.008). Although the preoperative absolute differences in VT and UV between the affected side and normal contralateral side were not significantly different from postoperative values (p ¼ 0.191 and p ¼ 0.109), the difference in RI significantly improved (p ¼ 0.043). Four patients had no progress in their OA grade. The remaining one patient with grade 1 OA progressed to grade 2 OA at the final follow-up (Table 2). VAS and PRWE were significantly improved (p ¼ 0.006 and p ¼ 0.043). Four of the five patients showed improvement in VAS greater than the MCID value (3.0); all five
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
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K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx Table 3 Clinical assessment. Assessment
Before Surgery
After Surgery
P value
Wrist ROM Forearm ROM Grip strengtha, % VAS, cm PRWE
93 ± 41 144 ± 38 54.0 ± 14.8 4.1 ± 1.6 41.6 ± 22.0
146 ± 23 164 ± 13 85.8 ± 18.8 0.9 ± 0.7 15.7 ± 19.5
0.085b 0.240b *0.003b *0.006b *0.043c
ROM, range of motion; VAS, visual analog scale; PRWE, the patient-rated wrist evaluation. P values are statistically significant (*P < 0.05). a Percentage of the contralateral limb. b Indicates p value from paired t-test. c Indicates p value from Wilcoxon signed-rank test.
Fig. 9. B is the displaced position of the fracture from A. C is intersection of the approximate circle on the articular surface and a line connecting the center of this circle and B. The distance CB is defined as the step-off.
patients showed improvement in PRWE greater than the MCID value (14). Moreover, grip strength significantly increased (p ¼ 0.003). The preoperative and postoperative total arc of the wrist and forearm ROM were not significantly different (p ¼ 0.085 and p ¼ 0.240) (Table 3). There were no major complications related to the surgery.
4. Discussion Intra-articular malunion of the distal radius is one of the major complications after distal radius fracture [4]. Residual intraarticular deformity of more than 2 mm results in poor wrist function. Reducing the step-off of the articular surface is considered the optimal treatment to recover wrist function. However, correction of the intra-articular malunited fragment without capsule release requires advanced arthroscopic skills and special tools, such as the osteotome and arthroscopic guide, for inside-out intra-articular osteotomy [11]. The salvage procedure of radiocarpal arthrodesis is one of the treatments for relief of wrist pain, although decrease in wrist ROM is inevitable. The total arc of wrist ROM after partial wrist arthrodesis for posttraumatic wrist OA was 49 e98 [8,22e24]. Intra-articular corrective osteotomy using various approaches, such as direct view with arthrotomy [14], fluoroscopic guidance, arthroscopic assistance [11], and patient-specific drill guide [16], has been reported to result in postoperative wrist ROM Table 2 Radiographic assesment. Assessment
Before Surgery
After Surgery
P value
Step-off, mm VTa RIa UVa, mm Osteoarthritis
4.9 ± 1.8 7.0 ± 6.0 5.4 ± 3.4 2.4 ± 2.4 G0: 0, G1: 3, G2: 2, G3: 0
1.0 ± 0.2 2.8 ± 1.3 1.2 ± 1.1 0.4 ± 0.5 G0: 0, G1: 2, G2: 3, G3: 0
*0.008b 0.191b *0.043c 0.109c e
VT, volar tilt; RI, radial inclination; UV, ulnar variance. G0-3: grade0-3. P values are statistically significant (*P < 0.05). a Difference to the contralateral side. b Indicates p value from paired t-test. c Indicates p value from Wilcoxon signed-rank test.
ranging from 112 to 145 , which is superior to the results of partial arthrodesis. However, intra-articular osteotomy is technically demanding and has a risk of bone necrosis of separated fragments by the release of soft tissues attached to them and postoperative joint stiffness. Therefore, we attempted to develop a 3-D computer simulation system and PMIs to enable intra-articular corrective osteotomy for intra-articular malunion of the distal radius without damage to the capsule and radiocarpal ligaments. We have reported reliable use of these novel technologies for long bone deformity in the upper extremity [25,26] and described the first case of intra-articular malunion of the distal radius treated with a PMI through an extra-articular approach [15]. Schweizer et al. [16] reported six case series treated by a palmar, dorsal, or combined approach with corrections of multiple fragments using PMIs. They also quantitatively evaluated the intra-articular correction of stepoff using preoperative and postoperative 3-D CT models and reported accurate correction and good clinical results. We also quantitatively evaluated the reduction of intra-articular step-off using preoperative and postoperative CT scans. Additionally, we investigated clinical findings, including patient-reported outcomes (VAS and PRWE). PMIs provided highly accurate reduction with an average residual step-off of 1.0 ± 0.2 mm, similar to the results of Schweizer et al. [16] RI also significantly improved. Although the absolute differences in VT and UV between the affected side and normal contralateral side were statistically insignificant, the postoperative values of 2.8 ± 1.3 and 0.4 ± 0.5 mm were clinically accepted. The VAS score for wrist pain improved beyond the MCID in four of five patients. PRWE improved beyond the MCID in all five patients. One patient (case 4) whose OA proceeded from grade 1 to 2 had a deformity of step-off with 7.8 mm. The degree of preoperative deformity would affect the progression of OA, despite being corrected to 1.1 mm postoperatively. As for the PMI, we added the reference guide on it through which the K-wire could point to the anatomical landmark of the distal radius for the confirmation of position because PMI placement directly affects the accuracy of osteotomy. This refinement would improve the reliability of the PMI. Intra-articular corrective osteotomy through the extra-articular approach using the PMI designed based on preoperative 3-D simulation achieved accurate correction of intra-articular deformity and provided good postoperative results, including patientreported outcomes, independently of the surgeon's skill. The limitations of our investigation include the small number of cases and the several different fracture types. Although a larger number of participants might have resulted in different findings, the a priori power analysis and a sample size of four patients had a statistically high power of >80% for the step-off in the post hoc power analysis (p ¼ 0.05). The lack of a control group was also a major limitation. Prospective randomized controlled trial is required to prove the utility of a PMI for intra-articular corrective
Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005
K. Oka et al. / Journal of Orthopaedic Science xxx (xxxx) xxx
osteotomy [27]. Because different surgeons performed the corrective osteotomies, the clinical results may have been influenced by surgical skill. However, the specialized hand surgeons had more than 10 years of experience each, and therefore, the effect of surgical skill on the results was likely minor. Variations in the treatment strategy (volar or dorsal approach) may also have affected the surgical results. However, including variations of intra-articular malunion in the same group of intra-articular step-off deformity is acceptable, considering the degree of intra-articular step-off mostly affects the wrist function. CT of the wrist was preoperatively and postoperatively performed in this study to evaluate the stepoff, which highlights radiation exposure in patients. However, our CT protocol reduced the radiation exposure to <1/10 under normal conditions of CT parameters [17]. Measurement of the deformity is necessary to evaluate the present procedure. Finally, time and expense are required for computer simulation and manufacturing of the PMI. Computer simulation takes approximately 3 h. The cost of manufacturing the PMI is US$1500 to US$2000 in Japan but may vary depending on the situation. Our results indicate adequate reliability of these technologies. Although there are some limitations, we believe that 3-D preoperative simulation and intra-articular osteotomy using a PMI could be reliable treatment options for intra-articular malunion. In particular, PMI is useful for intra-articular malunion once bone union is completed and where the original fracture line cannot be identified during surgery before osteoarthritis progression. The PMI not only has exceptionally high precision performance but is also anticipated to yield superior surgical results, regardless of the surgeon's skill. Declaration of Competing Interest Tsuyoshi Murase and Kunihiro Oka received funding in support of this research from the Japan Society for the Promotion of Science. Tsuyoshi Murase receives research support from Teijin Nakashima Medical Co., LTD., during of the study. Tsuyoshi Murase and Oka owns stocks of Orthree Co. LTD. The other authors declare that there is no conflict of interest. Acknowledgments This work was supported by the Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science, Grant Number JP 18K12104 and 19H03783. References [1] Gehrmann SV, Windolf J, Kaufmann RA. Distal radius fracture management in elderly patients: a literature review. J Hand Surg Am 2008 Mar;33(3):421e9. [2] Ali M, Brogren E, Wagner P, Atroshi I. Association between distal radial fracture malunion and patient-reported activity limitations: a long-term followup. J Bone Joint Surg Am 2018 Apr 18;100(8):633e9. [3] Jupiter JB. Complex articular fractures of the distal radius: classification and management. J Am Acad Orthop Surg 1997 May;5(3):119e29. [4] Knirk JL, Jupiter JB. Intra-articular fractures of the distal end of the radius in young adults. J Bone Joint Surg Am 1986 Jun;68(5):647e59. € rensen A, [5] Buijze GA, Leong NL, Stockmans F, Axelsson P, Moreno R, Ibsen So Jupiter JB. Three-dimensional compared with two-dimensional preoperative planning of corrective osteotomy for extra-articular distal radial malunion: a multicenter randomized controlled trial. J Bone Joint Surg Am 2018 Jul 18;100(14):1191e202.
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Please cite this article as: Oka K et al., Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using threedimensional surgical computer simulation and patient-matched instrument, Journal of Orthopaedic Science, https://doi.org/10.1016/ j.jos.2019.11.005