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| ORIGINAL ARTICLE |
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| Year : 2017 | Volume
: 9
| Issue : 2 | Page : 106-111 |
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Nonunion scaphoid treated with vascularized pronator quadratus osteomuscular transposition flap: A review of 11 cases
Varun Goel1, Neeraj Valecha2, Basant Kumar Bhuyan3, Santosh Kumar Sharma2, Vivek Singh2
1 Department of Orthopaedics, Late Shri Lakhiram Agarwal Memorial Medical College, Raigarh, Chhattisgarh, India
2 Department of Orthopaedics, R.D. Gardi Medical College, Ujjain, Madhya Pradesh, India
3 Department of Orthopaedics, IMS and SUM Hospital, Bhubaneswar, Odisha, India
| Date of Web Publication | 14-Dec-2017 |
Correspondence Address:
Dr. Varun Goel
Beside Prachi Medicose, Gandhi Ganj, Raigarh - 496 001, Chhattisgarh
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jotr.jotr_25_17
Overview: Nonunion scaphoid is a common complication of fracture scaphoid which always remains a difficult surgical problem. Most of the cases present late with persistent pain and disability, not responding to conservative treatment. Simple bone grafts are generally not enough in cases with evidence of decreased vascularity of proximal fragment, so pronator quadratus osteomuscular transposition flap to revascularize the nonunion scaphoid gained popularity. A series of 11 cases treated using vascularized osteomuscular graft. Materials and Methods: This study was done on eleven cases of nonunion scaphoid with pronator quadratus vascularized bone graft. Herbert and Alnot classification was used and postoperative evaluation done by scaphoid outcome score. Results: Postoperative scaphoid outcome score was excellent in 4 cases, good in 4 cases, fair in 2 cases, and poor in 1 case. One case developed scaphoid nonunion advanced collapse and wrist arthritis and revision surgery with proximal row carpectomy was done in it. The mean follow-up period was 22 months. Conclusion: Bone grafting is the mainstay treatment for non-union scaphoid. Vascularized bone grafts using pronator quadratus osteomuscular flaps have proved to be more biological and more successful treatment option.
Keywords: Nonunion scaphoid, osteomuscular flap, pronator quadratus, vascularized bone graft
How to cite this article:
Goel V, Valecha N, Bhuyan BK, Sharma SK, Singh V. Nonunion scaphoid treated with vascularized pronator quadratus osteomuscular transposition flap: A review of 11 cases. J Orthop Traumatol Rehabil 2017;9:106-11 |
How to cite this URL:
Goel V, Valecha N, Bhuyan BK, Sharma SK, Singh V. Nonunion scaphoid treated with vascularized pronator quadratus osteomuscular transposition flap: A review of 11 cases. J Orthop Traumatol Rehabil [serial online] 2017 [cited 2023 Apr 1];9:106-11. Available from: https://www.jotr.in/text.asp?2017/9/2/106/220762 |
| Introduction | |  |
Scaphoid, lateral bone of proximal carpal row, is the largest and most mobile [1] of all. It is the most common carpal to get fractured. Scaphoid is very notorious to go into nonunion and ultimately avascular necrosis (AVN) which inevitably causes scaphoradial arthritis. The reasons behind it are the major alterations in the kinematics of wrist,[2] its vulnerable blood nourishment,[3],[4] the oblique alignment and its multiplanar motion. Compressive forces tend to collapse and angulate the fracture fragments; proximal pole tends to extend whereas the distal pole tends to flexion collapse, termed as “concertina effect” by Fisk.[1]
Studies have shown that 95.6% of total scaphoid fractures are of waist and of these 63% are displaced fractures.[5] Fracture of the proximal pole has higher chances of AVN.[6],[7]
Scaphoid has two major blood vessels along palmar and dorsal surface. Studies have shown that vessels enter through nonarticular surface of distal half and palmar vessels enter through the tubercle. These arteries are direct branches of radial artery (83.33%), and in 16.67%, its branch of superficial palmar branch of radial artery. Dorsal vessels nourish the proximal two-third of the scaphoid.[8] Scaphoid is vascularized 80% by its dorsal vessels and 20% by palmar vessels.[4]
Advanced scoring system and techniques with longer follow-up period have shown that proximal pole scaphoid fractures and displaced fractures have a very low bone union rates which frequently landed into nonunion and AVN of proximal fragment.[9] The mainstay treatment for scaphoid nonunion is bone grafting. Free cancellous or nonvascularized bone grafts has certain limitations and showed failure rates as high as 65%.[4] Nonvascularized bone grafts thus proved less beneficial for cases of AVN.[10] For these conditions, vascularized bone grafts gained the greatest popularity as it was a more biological solution. It preserves the viability of osteoblasts and osteoclasts, prevents bone resorption, and shortens the time of bone graft incorporation.
| Materials and Methods | | |
This study was done on 10 cases of nonunion scaphoid with pronator quadratus vascularized bone graft. Among the patients, all eleven were men. Four of the patients were farmer, three were students, three were laborers, and one was businessman. Their mean age was 32 years (ranging from 22 to 52 years). About 72.73% fractures were of the right hand and 27.27% of the left hand. The mode of injury for nine patients was fall on hyperextended wrist following road traffic accident, one had injury following punching, and the mode was uncertain for one patient. Meantime period between injury and surgical intervention was eight months (ranging from 6 to 15 months).
The evaluation was done clinically on the basis of pain, function, patient's perception of motion, and overall satisfaction and postoperative scores according to scaphoid outcome score [Table 1] and radiological evaluation was done by X-rays in the anteroposterior view, lateral view and scaphoid views. The radiological evaluation was supported by computed tomography scans and magnetic resonance imaging to diagnose nonunion and AVN of scaphoid [Table 2].
We have included 11 patients in the study who were symptomatic and had nonunion or AVN of scaphoid. Acute fractures and revision surgery patients were excluded from the study. Patients with inadequate clinical records, compound fractures, patients with congenital or healing disorders such as diabetes or severely morbid patients were also excluded from the study.
Most common way to classify scaphoid classification is through Herbert classification [6] [Table 3]. There were 3 cases of type D1 and 8 cases of type D2.
According to Alnot classification [11] [Table 4], all the eleven cases were of type 2a and 2b. None of the patients had radioscaphoid or radiocarpal arthritis or proximal pole necrosis.
Operative technique
The technique was given by Kuhlmann et al.[12] Osteomuscular graft was taken from anteromedial cortex of distal radius with a pedicle of lower fibers of pronator quadratus muscle. This muscle pedicle has a volar carpal branch of anterior interosseous artery which nourishes the graft.
Brachial block was given in all the patients and a digital pneumatic tourniquet applied over the arm. A classic anterior incision (Henry's incision) was given and scaphoid exposed. The Nonunion areas of both proximal and distal fragment of scaphoid were identified and curetted [Figure 1]a and [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d. Dead and fibrous tissues removed. | Figure 1: (a) Freshening the scaphoid fracture margins. (b) Harvesting the pronator quadratus vascularized graft from distal radius. (c) Placing the graft in between the fracture fragments and fixing it with 2 k-wires
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 | Figure 2: (a) Case no. 3, preoperative X-ray anteroposterior view showing scaphoid fracture through the waist. (b) Case no. 3, preoperative X-ray lateral view. (c) Case no. 3, preoperative X-ray scaphoid view. (d) Case no. 3, preoperative magnetic resonance imaging. (e) Case no. 3, postoperative X-ray anteroposterior view showing good reduction with 2 k-wires in situ. (f) Case no. 3, postoperative X-ray lateral view. (g) Case no. 3, 6 months postoperative X-ray anteroposterior view. (h) Case no. 3, 6 months postoperative X-ray lateral view. (i) Case no. 3, 6 months postoperative X-ray scaphoid view
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The incision was then extended proximally to expose the donor site. Graft harvested from anteromedial cortex of radius with intact inferior fibers of pronator quadratus and its supplying artery. Pronator quadratus was freed from its origin subperiosteally to make the osteomuscular flap mobile [Figure 1]b. The tourniquet was then deflated to confirm graft vascularity. The graft is then put into the scaphoid bony defect without putting strain on pedicle and fixed with a k-wire from distal to proximal fashion [Figure 1]c, [Figure 2]e, [Figure 2]f. Wound closed in layers and below elbow slab applied in neutral position.
In the postoperative follow-up, 14 days after surgery, the sutures were removed and all patients were immobilized in a plaster cast including the wrist and thumb for four weeks (wrists then were splinted after removal of the plaster cast, at which time patients were encouraged to mobilize their wrists), and all Kirschner wires were removed within ten weeks of operation in three cases (where they were kept out) and after radiological signs of union in all other cases (where they were buried under the skin). The patients were encouraged to do physiotherapy to improve the mobility and regain strength.
Nonunions were considered healed after radiographic evidence of bone consolidation (bridge trabeculae on both sides of the graft, with attenuation of the continuity solution lines in the scaphoid). When such parameters were not observed, residual nonunion of the scaphoid was considered present.
| Results | | |
Utmost care was taken intraoperatively not to damage or fracture muscle pedicle or its vessel. There were no perioperative complications. Mean follow-up period was 22 months (12–27 months) [Table 2].
The assessment of clinical outcome was done according to scaphoid outcome Score under the following points: pain, function, patient's perception of motion, and overall satisfaction. Postoperative X-rays were done to analyze radiological bone union.
Ten out of total 11 cases had a satisfactory clinical outcome, one case complained of restricted and painful wrist movements but united and one case went into AVN and arthritis (scaphoid nonunion advanced collapse [SNAC]). None of the cases had postoperative complications such as infection or k-wire migration.
Scaphoid outcome score postoperatively was excellent in 4 cases (10–11 points), good in 4 cases (8–9 points), fair in 2 cases (6–7 points), and poor in 1 case (<5 points).
Seven out of eleven patients reported that their pain had improved by about 90% or had no pain at all. Pain assessed on the basis of change or limitation of activity, discomfort with strenuous work and frequency or duration of pain. Occasional pain, no change in activity, mild discomfort with strenuous use was still experienced by three patients and one experienced severe pain and serious limitations in activities [Table 2].
Functional outcome was good in ten patients whereas one patient had chronic pain and limitation/discomfort [Table 2].
A reasonable and useful range of movement was preserved in the majority of patients, with an average of 30° of extension, 31° of flexion, and 10° of radial and 20° of ulnar deviation. Overall, there was a loss of 7° of flexion-extension, but 9 patients had either a total range of more than 90°, or a gain of 30° when compared to the preoperative movement. A flexion-extension range of 50° with 25° of flexion and of extension is considered useful, and this was present in one of our patients. A severely restricted combined range with stiff joint occurred in one patient [Table 2].
Nine out of eleven cases showed good bone union radiologically (90.90% bone union rate) [Figure 2]g, [Figure 2]h, [Figure 2]i, one case did not show radiological union and had mild pain and restricted movements, but the activity of daily living was not hampered, so no intervention was done. However, one case showed signs of nonunion and AVN which later landed into SNAC and wrist arthritis. As the disability was significant revision surgery with proximal row carpectomy was done in this case ten months after primary surgery.
| Discussion | | |
Five to ten percent of scaphoid fractures treated nonoperatively may not achieve union [13] and the success rate may widely vary and has high chances of progressing to carpal collapse and ultimately wrist arthritis. Various bone grafts which yield 70%–92% success rates.[14],[15],[16],[17],[18],[19] Conventional free bone grafts and vascularized bone grafts have been compared in [Table 5]. | Table 5: Comparision of various types and techniques of bone grafts and its union rates
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Iliac crest is the most common site for the harvest of autologous nonvascularized bone graft for most orthopedic procedures. Its osteogenic and mechanical properties are well proven, and a large quantity of graft can be harvested. But in comparison, distal radius graft is easier to harvest. This involves the same extremity, and a smaller incision is needed. Although iatrogenic fracture is a potential complication while harvesting graft from the distal radius, a corticocancellous graft harvested from the middle part of distal radius with gentle hammering will avoid this complication. We have never encountered such problem in any of our cases.[20]
Vascularized pronator quadratus osteomuscular transposition flap from the anteromedial radius is a very high yielding and reliable surgical option for nonunion fracture scaphoid but harvesting such small graft with intact muscle pedicle and its nourishing vessel is a very meticulous and tactful technique. Another challenge was mobility of the graft and pedicle to the nonunion site. This requires experienced hands to achieve high success rates.
Postoperatively, mild-moderate pain is a very common and consistent problem. In our study, mild pain till 4–6 months postoperatively was seen, which later subsided with conservative treatment with analgesics and physiotherapy.
In our study, we used two k-wires to fix the graft in between the fractured scaphoid which when left outside skin had a problem of loosening and mild pin tract infection in postoperative period. All these problems can be minimized with the use of Herbert screws. However, the main drawback which limited us to use it in our study was its need for increased dissection and higher chances of displacement of small vascularized graft in between the scaphoid. Headless screw fixation although provides better compression but is technically more difficult.[21]
Smoking and increased age has also been shown to affect bone union.[22] Hence, we buried wires under the skin leaving about 3 mm from the bone surface for later surgical removal.
| Conclusion | | |
Excellent results with vascularized pedicle graft have changed the protocol for nonunion scaphoid completely and made the older technique obsolete.
Acknowledgments
We would like to thank the collaborators who cooperated in providing an encouraging environment for evaluation of patients and operating them and providing instruments and operating room needed for the procedures: Dr. VK Mahadik (Medical Director), Dr. NK Singh (Dean), Dr. JK Sharma. We also would like to thank all the seniors and juniors of orthopedic department and Department of Radiology and all operating room staffs and sisters for their support.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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