Percutaneous Fixation for Scaphoid Nonunion with Bone Grafting Through the Distal Insertion Hole of a Fully Threaded Headless Screw

3D printed guide-assisted percutaneous screw fixation for minimally displaced scaphoid waist fractures with delayed diagnosis or presentation

OBJECTIVES

To Investigate the value of 3D printed guide-assisted percutaneous management of minimally displaced scaphoid waist fractures(Herbert's B2) with delayed diagnosis or presentation.

METHODS

From October 2018 to February 2022, 10 patients with established delayed diagnoses and presentation of minimally displaced scaphoid waist fractures were treated with 3D printed guides assisted with percutaneous internal fixation without bone grafting. This technique was based on the patient's preoperative CT and imported into the software. Based on Boolean subtraction, the most centralized screw placement position was identified and a customized guide was produced. Intraoperative percutaneous insertion of the guide wire was assisted by the custom guide.

RESULTS

All 10 patients were successful in one attempt. The fractures healed at a mean of 7.7 weeks postoperatively (range 6-10 weeks). At a mean follow-up of 7.7 months (6-13 months), patients had excellent recovery of wrist function with minimal pain reduction. There were no major postoperative complications and the patients all returned to their previous activities before the injury.

CONCLUSIONS

Percutaneous internal fixation based on 3D printed guides is a safe and effective technique for delayed diagnosis or presentation of patients with minimally displaced fractures of the scaphoid waist. This method allows for easy insertion of screws and avoids multiple attempts.

Can CT-Scan Measurements of Humpback Deformity, Dislocation, and the Size of Bony Cysts Predict Union after Surgery for Scaphoid Nonunion?

Objective  Scaphoid fractures are associated with high rates of late- or nonunion after conservative treatment. Nonunion is reported to occur in approximately 10% of all scaphoid fractures. It is known that the union of scaphoid fractures is affected by factors such as location at proximal pole, tobacco smoking, and the time from injury to treatment. Same factors seem to affect the healing after surgery for scaphoid nonunion. While the impact of preoperative humpback deformity on the functional outcome after surgery has been previously reported, the impact of humpback deformity, displacement, and the presence of bony cysts on union rate and time to healing after surgery has not been studied. Purpose  The primary purpose of this study is to assess the association of humpback deformity, fragment displacement, and the size of cysts along the fracture line with the union rate and union time, following surgery of scaphoid nonunion. The second purpose of the study is to investigate the interobserver reliability in the evaluation of computed tomography (CT) scans of scaphoid nonunion. Patients and Methods  From January 2008 to December 2018, 178 patients were surgically treated in our institution. After exclusion criteria were met, 63 patients with scaphoid delayed- or established nonunion, and preoperative CT scans of high quality (<2mm./ slice), were retrospectively analyzed. There was 58 men and 5 women with a mean age of 30 years (range: 16-72 years). Four orthopaedic surgeons and one radiologist independently analyzed the CT scans. The dorsal cortical angle (DCA), lateral intrascaphoid angle (LISA), the height-to-length ratio, the size of the cysts, and displacement of the fragments were measured. Healing was defined by CT scan, or by conventional X-ray, and status of no pain at clinical examination. Thirty-two of the patients had developed nonunion (>6 months postinjury), while 31 were in a stage of delayed union (3-6 months postinjury). Results  Open surgery with cancellous or structural bone graft was the treatment of choice in 49 patients, 8 patients were treated with arthroscopic bone grafting, and 6 patients with delayed union were operated with percutaneous screw fixation, without bone graft. Overall union rate was 86% (54/63) and was achieved after 84 days (12 weeks) (mean). The failure rate and time to healing were not associated with the degree of the humpback deformity, size of the cysts, or displacement of the nonunion in general. However, greater dislocation, and the localization of the nonunion at the scaphoid waist, showed significant influence on the union rate. Dislocation at nonunion site, in the group of the patients who united after surgery, was 2.7 mm (95% confidence interval [CI]: 1.5-3.7), and in the group who did not unite was 4.2 mm (95% CI: 2.9-5.7); p  = 0.048). Time from injury to surgery was significantly correlated with time to union ( p  < 0.05), but not associated with the union rate ( p  < 0.4). Patients treated arthroscopically achieved faster healing (42 days), (standard deviation [SD]: 22.27) as compared with patients treated by open techniques (92 days; SD: 70.86). Agreement among five observers calculated as intraclass correlation coefficient was for LISA: 0.92; for height-to-length ratio: 0.73; for DCA: 0.65; for size of cysts: 0.61; and for displacement in millimeters: 0.24, respectively. Conclusions  The degree of humpback deformity and the size of cysts along the fracture line of scaphoid nonunion have no predictive value for the result, neither for the union rate nor the union time after surgery for the scaphoid nonunion. However, larger dislocation of the fragments measured at the scaphoid waist showed lower union rate. Time to healing following surgery is mainly influenced by the time from injury to the surgical treatment and may be influenced by the choice of the surgical technique. Interrater reliability calculation was best with LISA measurements, and worse with the measurements of the dislocation. Level of Evidence  This is a Level III, observational, case-control study.

Enxerto percutâneo e fixação de parafusos em pacientes com não consolidação do escafoide

Objective  The aim of the present study was to analyze the clinical and radiological results of patients with type-V cystic scaphoid nonunion who were treated with percutaneous grafting and screw.

Methods  A total of 11 patients were treated with a percutaneous bone graft with screw fixation. The criteria for inclusion in the study were a type-V scaphoid nonunion and age > 18 years old. Those with humpback deformity, arthritis, ligament damage determined on magnetic resonance imaging, or avascular necrosis (AVN) in the nonunion fragment were excluded from the study.

Results  The mean follow-up time was 36 months (range: 15–53 months). At the final follow-up examination, the mean visual analogue scale score was 1.06 (range: 0–2.3). Postoperatively, the mean extension was 61.6° (44–80°), flexion 66° (60–80°), radial deviation 12° (7–20°), and ulnar deviation 25° (20–34°). The mean grip strength of the operated hand was found to be 94%, compared with the healthy side. The results obtained in the Mayo Modified Wrist Score were poor in 2 patients, good in 2 and excellent in 7 (64%). With the exception of 2 patients, union was obtained radiologically in 9 patients, with a mean of 12.6 weeks (range, 8–16 weeks).

Conclusion  Percutaneous grafting and screw fixation cannot replace open surgery in cases with deformity, shortening, humpbacking, or in long term nonunions; however, it is a reliable and effective treatment method in selected cases, such as Slade & Dodds type-V cystic nonunion.

Arthroscopically Assisted Bone Grafting Reduces Union Time of Scaphoid Nonunions Compared to Percutaneous Screw Fixation Alone

Purpose  Minimally invasive techniques have been recommended in the treatment of painful but stable scaphoid nonunions. The purpose of this study was to determine if arthroscopically assisted bone grafting provided superior results in healing as compared to percutaneous screw fixation. Materials and Methods  One hundred sixty-four consecutive patients with scaphoid nonunions were retrospectively analyzed. One hundred forty-eight patients were treated with the open grafting techniques either with iliac or distal radius bone, leaving 16 patients treated with minimally invasive surgery. In the group treated percutaneously ( n  = 8), the time from injury to surgery was 2.5 months (range: 2-4 months) and it was 27.3 months (range: 3-180 months) in the arthroscopic group ( n  = 8). The mean age was 39 years (range: 20-66) in the percutaneous group and 22 years (range: 16-32) in the arthroscopic group. In all cases, the Mini Acutrak headless fully threaded compression screw was used. Healing was assessed clinically and radiographically at a minimum follow-up of 12 weeks, mean 7 months (range: 3-12 months). Data were calculated with two-tailed Mann-Whitney U test based on p -value of < 0.05 that was considered statistically significant. Results  We recorded no complications in any of the groups. Patients treated arthroscopically received cancellous bone grafting from the distal radius and all patients but one healed at a median of 7.8 weeks (range: 5-18 weeks). Seven patients in the percutaneous group healed at a mean of 10.5 weeks (range: 7-24 weeks), thus leaving one patient from each group without achieving union. Mann-Whitney U test showed the U value of 11, the critical value of U to be 13 ( p  < 0.05), thus significantly faster healing was observed in the arthroscopically treated group. Conclusions  Arthroscopically treated patients achieved faster healing despite shorter time to surgery in the percutaneous group. Local bone grafting is considered as the main reason for this outcome. Younger population in the arthroscopically treated group may have influenced the result. Level of Evidence  This is a Level III comparative study.