Remember me
ORIGINAL ARTICLE
Year : 2022 | Volume
: 11
| Issue : 4 | Page : 171-176
Comparison of the outcomes of vascularized and nonvascularized bone grafting in treatment of scaphoid nonunion
Ali Tabrizi1, Hooman Bakhtaki1, Sina Dindarian2, Maryam Najafi3
1 Department of Orthopedics, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran
2 Student Research Committee, Urmia University of Medical Sciences, Urmia, Iran
3 Trauma Research Center, Kashan University of Medical Sciences, Kashan, Iran
Correspondence Address:
Ali Tabrizi
Modaress Street, Ershad Boulevard, Urmia, 57157 81351
Iran
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/atr.atr_1_22
Background and Objectives: Scaphoid fractures are common fractures of the upper extremity and more than 5% of them progress to nonunion. Nonvascularized bone grafting (NVBG) and vascularized bone grafting (VBG) are used to treat this fracture and the best option for the treatment of scaphoid nonunion (SN) is controversial. Hence, this study aimed to compare the clinical outcomes of VBG and NVBG in treatment of SN. Materials and Methods: This quasi-experimental study was conducted on 30 patients with SN. The patients were divided into two groups of NVBG (n = 15) and VBG (n = 13) and were followed up at 2, 4, 8 weeks, and at least 10 months after surgery. Patients' functional abilities in both groups were compared using the Quick Disabilities of the Arm, Shoulder, and Hand (DASH) Questionnaire and the Mayo modified wrist score. Severity of pain was also compared using the Visual Analog Scale (VAS) before and after the surgery. Results: Union rates between the VBG (92.3%) and NVBG (73.3%) groups were not significantly different (P = 0.1). There was a significant difference in the VAS score (P = 0.03) and grip strength (P = 0.010) between the two groups. However, no significant difference was found regarding the active range of motion between the groups (P = 0.2). The postoperative Quick DASH scores of the VBG and of NVBG groups were 5.6 ± 1.1 and 8.4 ± 2.3, respectively, and the difference was significant (P = 0.001). The functional improvement based on the postoperative Mayo score was significantly higher in the VBG group compared with the NVBG group (85.9 ± 3.04 vs. 80.4 ± 6.6; P = 0.006). Conclusion: Vascularized bone grafting seems to be a preferable treatment option for SN because of its higher union rate and better functional outcomes.
Keywords: Bone graft, functional outcome, nonunion, nonvascularized, Scaphoid, vascularized
Accounting for more than 60% of all carpal fractures, scaphoid fractures are the second most common fractures of the upper extremity after distal radius fractures.[1] The highest occurrence rate of scaphoid fractures are in young men in the second and third decades of life.[2] Among different populations, the annual occurrence rate of scaphoid fractures ranges from 0.08 to 1.21 per 1000 people. Studies show that more than 5% of all scaphoid fractures progress to nonunion fractures.[3] Diagnosis of scaphoid nonunion (SN) in radiography is hard and this fracture usually does not cause severe pain and work limitation. Thus, delay in diagnosis may cause severe complications, such as instability and degenerative changes (SN advanced collapse).[4] Various nonvascularized bone grafting (NVBG) and vascularized bone grafting (VBG) procedures are used to treat this fracture including 1, 2-intercompartmental supraretinacular artery pedicled vascularized bone graft (1,2-ICSRA-VBG), free vascularized medial femoral condyle bone transfer,[5] and the free iliac crest bone graft.[6] It is believed that vascular-based bone graft is a better treatment option because of its faster healing process due to activity of living cells providing nutrition to the bone structure, less immobilization period, and higher chance of stability.[7] However, still the best option for the treatment of SN remains controversial. For instance, VBGs are technically more challenging than NVBGs, requiring microsurgical techniques[6],[8] and resulting in prolonged surgical time, and donor-site morbidity.[9] If the fracture can be successfully repaired with NVBG, it is not necessary to use VBG techniques. However, the rate of union by NVBG methods differs from 60% to 95% in various papers, while in VBG, the rate ranges from 80% to 100%. Obviously, the use of VBG is more beneficial when NVBG may result in graft failure.[5],[8],[10],[11] Hence, the present study aimed to prospectively evaluate the clinical outcomes of VBG compared to NVBG in treatment of nonunion scaphoid fractures.
Materials and MethodsStudy design
This quasi-experimental study was conducted on 30 patients with SN from April 2015 to April 2018. Demographic factors, features of the fractures (the site and time of fracture), type of surgery, and functional status of the patients were extracted from the medical records of the Orthopedic Department of the Trauma Center in Imam Khomeini Hospital of Urmia (in the northwest province of Iran). Urmia is located at a distance of 900 km from the capital of Iran with a population of about 1.5 million people. The exclusion criteria included congenital deformity of the wrist, previous history of trauma, previous wrist injuries, and previous history of consumption of corticosteroids and anabolic drugs. Flow diagram of the study protocol is shown in [Figure 1]. Thirty patients with SN presented with avascular necrosis (AVN) in waist or proximal pole of the scaphoid were eligible for this study. The patients were divided into two groups of 15 patients based on patients' consent and hand surgeon's decision. The vascularity of scaphoid was determined using MRI imaging.
Fifteen cases were treated by VBG (VBG group) and 15 patients underwent nonvascularized iliac crest bone grafting[10],[12] without hardwire fixation (NVBG group). In the VBG group, VBG was done according to the Zaidemberg's technique,[10],[12] then fixation was performed by 1.5 mm Kirschner (K) wire [Figure 2], [Figure 3], [Figure 4]. Postoperatively, all of the patients in both groups immobilized with a cast for at least 6 weeks and then the thumb spica casts and pins were removed if union was achieved, and afterwards wrist functional splints were used. Two of the patients in the VBG group were lost to follow-up after surgery. The remaining 28 patients were followed up at 2, 4, and 8 weeks after surgery and also control radiography was performed for them [Figure 5]. Finally, the patients were followed up for at least 10 months after the treatment and functional abilities of the patients in both groups were determined and compared using the disabilities of the arm, shoulder, and hand (Quick DASH) questionnaire[13] and the Mayo modified wrist score[14] before and after the surgery. Furthermore, the severity of pain before and after the surgery was compared in both groups using the Visual Analog Scale (VAS) ranging from 0 (no pain) to 100 (maximal pain). Finally, post-treatment complications including locomotor restriction, wrist joint osteoarthritis, nerve injury associated with anesthesia, and motor impairment (due to tendon injury) were compared between the groups.
Figure 3: Clinical photo showing the dorsal branch of radial artery in the preparation of vascularized distal radius bone graft
Figure 4: Postoperative radiography after graft insertion and fixation using K-wire
Figure 5: Final follow-up radiography indicating the union of scaphoid fractureStatistical analysis
Descriptive data were given as mean ± standard deviation for each group. For continuous scales variables, we used t-test or Mann–Whitney U-test where applicable. In addition, to compare categorical variables, we used Chi-square, or Fisher's exact tests. Statistical analysis was performed using IBM SPSS Statistics 20 (SPSS Inc., Chicago, IL, USA). The value of P < 0.05 was considered statistically significant.
Ethical approval
All procedures were in accordance with the ethical standards of the 1964 Helsinki declaration and its later amendments and were approved by Ethics Committee, Urmia University of Medical Sciences, Urmia, Iran, with the approval code IR. UMSU. REC.1397.107. The results of this study were part of student thesis. We also obtained informed consent from all of the participants.
ResultsThe total number of participants included 28 patients with SN and AVN (27 males and 1 female) ranged from 20 to 47 years old with the mean age of 27.4 ± 6.7 years. Thirteen patients (12 males and 1 female) were treated with VBG and 15 male patients were treated with NVBG. Demographic and clinical characteristics of the two groups are summarized in [Table 1]. There was no significant difference regarding sex (P = 0.2) and age (independent t-test, P = 0.9) between the two groups. The mean delay between the fracture and the surgery for the treatment of nonunion was almost the same in both groups (14.9 months in VBG vs. 13.5 months in NVBG; P = 0.4). Furthermore, no significant difference was found regarding the injured hand, site of injury, and follow-up time.
Overall 23 patients achieved union in both groups. The rate of union was 92.3% (n = 12) in the patients treated with VBG and 73.3% (n = 11) in the patients treated with NVBG. Although more patients in the VBG group achieved union, there was no significant difference in the healing process between the two groups (P = 0.1).
In vascularized bone grafts, superficial radial neuropathy was found in 4 cases (30.8%), and the complex regional pain syndrome was found in only 1 case (7.6%). None of these complications was found in the NVBG group. The postoperative outcomes of patients achieving union at the end of the follow-up time are shown in [Table 2]. The severity of pain was compared based on the VAS score between the two groups and the results showed statistically significant differences between the scores of the two groups (P = 0.03). Furthermore, grip strength and an active range of motion (AROM) were compared in both grafts and significant differences were observed between the two groups for grip strength (vascularized vs. non VBG [NVBG]; 44.9 ± 3.2 vs. 49 ± 7.1 kg; P = 0.01). No significant difference was found in AROM between the groups (P = 0.20). [Table 3] compares the pre- and post-operative functions of the patients in both groups using Mayo-wrist and Quick DASH scores. The postoperative Quick DASH scores of the VBG and NVBG groups were 5.6 ± 1.1 and 8.4 ± 2.3, respectively, which showed a significant difference (P = 0.001). The functional improvement based on the postoperative Mayo score was significantly higher in the VBG group compared with the NVBG group (85.9 ± 3.04 vs. 80.4 ± 6.6; P = 0.006). In addition, [Figure 6] and [Figure 7], respectively, show the changes in MAYO and Quick DASH scores of the two groups before and after surgery.
Table 2: Clinical and functional outcomes of patients after surgical union using the visual analogue scale score, active range of motion, and grip strength
Table 3: Comparison of pre- and post-operative functions of patients in both groups using Mayo wrist and Quick DASH scores
Figure 6: Changes in MAYO scores of the two groups before and after surgery
Figure 7: Changes in Quick DASH scores of the two groups before and after surgery. Quick DASH: Quick disabilities of the arm, shoulder and hand Discussion The major goals of SN treatment are relieving pain and increasing function as well as prevention of degenerative osteoarthritis and carpal deformity.[15],[16] Till now, various approaches have been used to treat SN such as NVBGs, VBGs, and dorsal and volar pedicled VBGs. Despite the VBG, which requires microsurgical treatment, these procedures are technically easier and are still widely performed.[6],[17] In the current study, we demonstrated relatively better functional outcome scores in the VBG group despite higher rates of complications. In the present study, the rates of union in the VBG and NVBG groups were 92.3% and 73.3%, respectively; however, no significant difference was found in the healing process. Furthermore, the results of two other prospective studies showed better healing rates[18] and faster bone healing[19] using the VBG method. In a systematic review, Ferguson et al.[20] evaluated the outcomes of VBG and NVBG in 5464 patients with nonunion scaphoid and they reported that the union rates in patients treated with VBG and NVBG were 84% and 80%, respectively. Moreover, a recent review of evidence of 41 publications demonstrated 84.7% union rate at 13 weeks after surgery in patients treated with vascularized bone graft.[21] Thus, although there is a better outcome in patients treated with VBG, the union rates are relatively similar in both methods in most of the studies.
Avascular necrosis is considered a risk factor for SN in previous studies.[22],[23] Furthermore, Chang et al.[24] demonstrated better union rates in patients without AVN. Malizos et al.[11] and Tsai et al.[25] found that AVN does not have a significant impact on union rates. The present study included 24 patients with AVN; all of 13 patients in the VBG group and 11 patients in the NVBG group were diagnosed with AVN. We observed a high union rate in patients with AVN in both groups. Especially, there was a union rate of 92.3% in patients with AVN who underwent VBG. A recent meta-analysis of 1827 SN restoration also demonstrated the dominancy of VBG in patients with AVN.[22] Furthermore, in the review of Ferguson et al.[20] they demonstrated that the union rates in patients with AVN who underwent VBG and NVBG were 75% and 62%, respectively. Most of the studies have reported VBG as a better method of treatment in patients with SN having AVN. However, since there is a controversy in the findings of studies investigating the impact of AVN on union rate, we recommend further studies to evaluate the effects of AVN on union following various methods of the SN treatment.
In the current study, complications were only found in vascularized bone grafts; 30.8% of the patients treated with VBG had superficial radial neuropathy and 6.7% of them had complex regional pain syndrome. In addition, in the review of Alluri et al.,[26] the most common complications were superficial infections (1.56%), neuropathic pain (1.56%), and complex regional pain syndrome (1.25%). In our study, we observed no complications in patients treated with NVBG. In addition, a low rate of complications occurrence in the review of Alluri et al. suggests that VBG is a better choice for SN.[27],[28] The present study does not fully support this claim. Further studies, especially prospective ones with a large sample size are recommended to compare the occurrence of complications in both methods.
In both surgical techniques, acceptable functional outcomes were observed. The Quick Dash score was significantly decreased in both groups in favor of the vascularized bone graft. The postoperative Mayo wrist score was increased from 48 to 85 in the VBG group and from 48 to 80 in the NVBG group and the difference was statistically significant. Furthermore, the VAS score and the grip strength were considerably higher in the NVBG group. In the study of Rahiminia et al.,[1] a modified Mayo wrist score (MMWS) improved from 60 to 83, postoperatively. Moreover, the Dash score decreased from 54 to 21, and grip strength decreased to 73% of the contralateral hand strength. This results are in accordance with those of Malizos et al.[11] and Hirche, et al.[29] Moreover, long-term results of SN surgeries in the study of Reigstad et al.[30] revealed that early surgery before the development of arthritis could positively affects MMWS, DASH, and VAS scores. Thus, both VBG and NVBG methods could be useful in the treatment of patients with SN, especially when it is conducted in an appropriate time. However, most of the studies consider VBG as a better method in improving the postoperative functions of SN.
One of the most considerable limitations of our study is the small sample size. Thus, the results of the current study cannot be generalized to the entire population. Furthermore, in the present study, we have not compared the function of the injured hand with the contralateral hand. Finally, we could not determine the exact healing time due to the long interval of follow-up. Studies with larger sample sizes, especially those evaluating and comparing the long-term outcomes of both methods, are strongly recommended in this field.
ConclusionAlthough the rate of complications occurrence in patients treated with vascularized bone graft is higher, it seems to be a preferable treatment option for SN in comparison with NVBG due to high union rates and better functional outcomes, especially in patients with AVN.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
Comments (0)