Title:
The effect of delayed treatment on clinical and radiological effects of anterior wedge grafting for non-union of scaphoid fractures.

Abstract:
The aim of the treatment of displaced scaphoid non-unions is the restoration of normal scaphoid anatomy. Restoration of normal scaphoid anatomy at an earlier stage might have functional benefits as maladaptive carpal ligament contractures and the development of preliminary osteoarthritis could be avoided. The purpose of this retrospective study was to determine if late reconstruction (delayed reconstruction group) was as effective as early reconstruction (early reconstruction group) of scaphoid non-union in restoring clinical and radiological outcome.
The early reconstruction group included patients who underwent surgery between 6 and 12 months after the original fracture. This group consisted of 14 male and 2 female patients. The delayed reconstruction group included patients who underwent surgery 12 or more months after the original fracture. This group consisted of 9 male and 1 female patients. Average time from injury to surgery in the early reconstruction group was 10 months (range 6-12 months) and mean postoperative follow-up period averaged 58 months (range 19-72 months). Average time from injury to surgery in the delayed reconstruction group was 69 months (range 12-88 months) and mean postoperative follow-up period averaged 62 months (range 24-80 months). All patients showed a humpback deformity as well as a DISI deformity with the radiolunate angle being greater than 15°. The outcome was assessed on the basis of measurement of active wrist range of motion and grip power. Wrist pain was evaluated using a visual analogue scale. Functional subjective outcome was evaluated with the DASH and PRWE scores. Results were compared to preoperative measurements as well as to the uninjured contralateral side. Pre- and post-operative radiographs were assessed for scapholunate angle (SLA) as a measure of palmar rotation and radiolunate angle (RLA). The presence of DISI was defined by a difference of >60° for the SLA or of >10° for the RLA between the affected and unaffected wrist.
In the early reconstruction group bone union and correction of DISI deformity could be achieved for all patients (n = 16). In the delayed reconstruction group bone union could only be achieved without correction of the DISI deformity in six patients (60 %). In four patients (40 %) of the delayed reconstruction group non-union persisted. For the early reconstruction group at final follow-up mean flexion-extension arc, mean ulnar-radial-deviation arc and mean grip strength were 82, 91.5 and 82 % of uninjured side, respectively. Mean pain level decreased from 6 points before surgery to 1 point at final follow-up. The preoperative DASH changed from 48 to 17 and the preoperative PRWE changed from 30 to 14. The SLA changed from 51° to 48° and the RLA from 18° to 9°. Six patients from delayed reconstruction group showed bone union, but no correction of DISI deformity at final follow-up. Functional and radiological results showed only slight improvement. The remaining four patients from delayed reconstruction group with a persistent non-union continued to experience pain, reduced grip strength and limited range of wrist movement and DISI deformity persisted.
In conclusion, wedge-shaped bone grafting of scaphoid non-union leads to increased functional scores as well as to improved carpal angles as long as bony union can be achieved. Remaining non-union and the inability to correct DISI deformity are severely correlated with an increased time frame between fracture and surgical treatment. Furthermore, the vascularization of the proximal fragment and patients' smoking habits has to be taken into consideration preoperatively.