Publication Excerpt

“Lateral fixation of AO type-B2 ankle fractures by the APCS (Acutrak Plus compression screw) is a safe and effective technique. It offers several advantages including stable fixation, a small surgical wound, less dissection of soft tissue, a headless device without palpable hardware, and easy applications with a short operating time.”

Journal Abstract

The Acutrak plus compression screw (APCS) (Acumed Inc., Beaverton, OR, USA) is an intramedullary implant which can achieve stable fixation with minimum soft tissue dissection. The characteristics of the APCS include fully-threaded length, headless, cannulated, and variable thread pitch. Twenty-three patients with AO type- B2 ankle fractures treated with lateral fixation by an APCS were retrospectively reviewed. Evaluation of postoperative roentgenograms for adequacy of reduction revealed a good reduction in 22 of 23 (95.7%) patients. The average wound incision was 4.1 cm. The operative time was 25.3 minutes. All the ankle fractures showed radiographic evidence of healing within four months. At the final follow-up, the ankle scores of the patients were evaluated for functional outcomes. Good to excellent results were obtained in 21 (91.3%) patients. No patient complained of symptomatic hardware. In conclusion, lateral fixation of AO type-B2 ankle fractures by APCS offers several advantages including stable fixation, a small surgical wound, less dissection of soft tissue, no palpable hardware, and easy application with a short operating time.

Reference

Chen SH, Huang CR, Hsu TL, Lee YS. Lateral fixation of AO type-B2 ankle fractures: the Acutrak Plus compression screw technique. Int Orthop. 2010;34(6):903-907.

Publication Excerpt

“Using a headless screw fixation for arthroscopic ankle arthrodesis prevents symptomatic metalwork prominence and the requirement for removal.”

Journal Abstract

Background
Arthroscopic ankle arthrodesis (AAA) is a recognized salvage procedure for end-stage arthritis. Its reported disadvantages include a high rate of re-operation for symptomatic prominence of metalwork. We propose that the use of a headless screw would reduce this re-operation rate.

Methods
We reviewed 32 AAAs, using the Acutrak 6/7 mm headless screw fixation system, to determine peri-operative parameters and complication rates.

Results
At an average of 22 months follow-up, 28 (88%) had united radiologically. There were 2 stable fibrous nonunions not requiring further intervention. Of the other 2, one was successfully revised using an open technique, and the other patient died of unrelated causes. There were no other complications in this series, with no cases of metalwork removal for prominence or pain.

Conclusion
Using a headless screw fixation for arthroscopic ankle arthrodesis prevents symptomatic metalwork prominence and the requirement for removal.

Reference

Odutola A, Sheridan B, Kelly AJ. Headless compression screw fixation prevents symptomatic metalwork in arthroscopic ankle arthrodesis. Foot Ankle Surg. 2012;18(2):111-113.

Publication Excerpt

“Performance of the tapered, fully threaded, variable pitch screws exceeded that of conventional lag screws regardless of whether two or three screws were used. Additional resistance to internal rotation afforded by a third screw placed anteriorly may offer some advantage in patients at risk for nonunion.”

Journal Abstract

Background
Subtalar joint arthrodesis is a common operative treatment for symptomatic subtalar arthrosis. Because excessive relative motion between the talus and calcaneus can delay or prohibit fusion, fixation should be optimized, particularly in patients at risk for subtalar arthrodesis nonunion. Tapered, fully-threaded, variable pitch screws are gaining popularity for this application, but the mechanical properties of joints fixed with these screws have not been characterized completely. We quantified the torsion resistance of 2-screw and 3-screw subtalar joint fixation using this type of screw.

Methods
Ten pairs of cadaveric subtalar joints were prepared for arthrodesis and fixed using Acutrak 2–7.5 screws. One specimen from each pair was fixed with two diverging posterior screws, and the ontralateral joint was fixed using two posterior screws and a third screw directed through the anterior calcaneus into the talar neck. Internal and external torsional loads were applied and joint rotation and torsional stiffness were measured at two torque levels.

Findings
Internal rotation was significantly less in specimens fixed with three screws. No difference was detectable between 2-screw and 3-screw fixation in external rotation or torsional stiffness in either rotation direction. Both 2-screw and 3-screw fixation exhibited torsion resistance surpassing that reported previously for subtalar joints fixed with two diverging conventional lag screws.

Interpretation
Performance of the tapered, fully threaded, variable pitch screws exceeded that of conventional lag screws regardless of whether two or three screws were used. Additional resistance to internal rotation afforded by a third screw placed anteriorly may offer some advantage in patients at risk for nonunion.

Reference

Riedl M, Glisson RR, Matsumoto T, Hofstaetter SG, Easley ME. Torsional stiffness after subtalar arthrodesis using second generation headless compression screws: Biomechanical comparison of 2-screw and 3-screw fixation. Clin Biomech. 2017;45:32−37.

Publication Excerpt

“Our study demonstrates that the Synthes headless compression screw experienced a greater loss of interfragmentary compressive force from the time of installation to the final steady state compression level. The higher post-installation compression of the Acutrak 2 Standard may be attributable to the greater number of threads throughout the entire length of the screw. The clinical significance of these results, are, at this point uncertain. We do demonstrate that a fully threaded design offers a more reliable compression that may translate to more predictable bony union.”

Journal Abstract

Purpose
The purpose of this study was to compare the interfragmentary compression force across a simulated scaphoid fracture by two commonly used compression screw systems: the Acutrak 2 Standard and the 3.0 mm Synthes headless compression screw.

Methods
Sixteen (8 pairs; 6 female, 2 male) cadaver scaphoids were randomly assigned to receive either the Acutrak 2 or Synthes screw with the contralateral scaphoid designated to receive the opposite. Guide wires were inserted under fluoroscopic control. Following transverse osteotomy, the distal and proximal fragments were placed on either side of a custom load cell, to measure interfragmentary compression. Screws were placed under fluoroscopic control using the manufacturer’s recommended surgical technique. Compressive forces were measured during screw insertion. Recording continued for an additional 60s in order to measure any loss of compression after installation was complete. The peak and final interfragmentary compression were recorded and paired t-tests performed.

Results
The mean peak compression generated by the Acutrak 2 Standard was greater than that produced by the Synthes compression screw (103.9 ± 33.2 N vs. 88.7 ± 38.6 N respectively, p = 0.13). The mean final interfragmentary compression generated by the Acutrak 2 screw (68.6 ± 36.4 N) was significantly greater (p = 0.04) than the Synthes screw (37.2 ± 26.8 N). Specimens typically reached a steady state of compression by 120-150s after final tightening.

Conclusion
Peak interfragmentary compression observed during screw installation was similar for both screw systems. However, the mean interfragmentary compression generated by the Acutrak 2 Standard was significantly greater. Our study demonstrates that the Synthes headless compression screw experienced a greater loss of interfragmentary compressive force from the time of installation to the final steady state compression level. The higher post-installation compression of the Acutrak 2 Standard may be attributable to the greater number of threads throughout the entire length of the screw. The clinical significance of these results, are, at this point uncertain. We do demonstrate that a fully threaded design offers a more reliable compression that may translate to more predictable bony union.

Reference

Grewal R, Assini J, Sauder D, Ferreira L, Johnson J, Faber K. A comparison of two headless compression screws for operative treatment of scaphoid fractures. J Orthop Surg Res. 2011;6:27.

Publication Excerpt

“The Acutrak screw enabled more accurate screw placement and achieved higher union rates and modified Mayo wrist scores than the Herbert screw did.”

Journal Abstract

Purpose
To compare the treatment outcome of Acutrak versus Herbert screw fixation for scaphoid non-union and delayed union.

Methods
Records of 132 patients who underwent Herbert screw fixation (n=61) or Acutrak screw fixation (n=71) with or without bone grafting for scaphoid non-union and delayed union by a single surgeon were reviewed. The most common fracture site was the waist of the scaphoid (n=95), followed by the proximal pole (n=31) and the distal pole (n=6). Screw placement was considered accurate (n=120) when the screw was placed in the central one-third (axially) of the scaphoid; otherwise it was eccentric (n=12). Bone union was assessed radiographically and clinically. Functional outcome was assessed using the modified Mayo wrist score.

Results
Respectively in the Herbert and Acutrak screw groups, the mean patient ages were 25.3 and 27.3 years (p=0.28), the mean intervals between injury Acutrak versus Herbert screw fixation for scaphoid non-union and delayed union and screw fixation were 12.2 and 17 months (p=0.38), the mean durations to bone union were 2.1 and 1.8 months (p=0.63), and the union rates were 77% and 93% (p=0.01). The union rate was significantly higher in fractures of the waist of the scaphoid than in the proximal and distal poles (94% vs. 71% vs. 33%, p=0.001). The union rate was significantly higher when the screw was placed accurately (axially) than eccentrically (Herbert screw: 84% vs. 40%, p=0.006; Acutrak screw: 96% vs. 0%, p=0.004). 84% of the Herbert screws were placed axially, compared to 97% for the Acutrak screws. Respectively, 67% and 85% of patients had satisfactory functional outcomes (p=0.03), whereas 23% and 7% of the patients had persistent non-union (p=0.05).

Conclusion
The Acutrak screw enabled more accurate screw placement and achieved higher union rates and modified Mayo wrist scores than the Herbert screw did.

Reference

Oduwole KO, Cichy B, Dillon JP, Wilson J, O’Beirne J. Acutrak versus Herbert screw fixation for scaphoid non-union and delayed union. J Orthop Surg (Hong Kong). 2012;20(1):61-65.

Publication Excerpt

“Distal digital joint arthrodesis with the AcuTwist resulted in a fusion rate of 94% with a complication rate of 9%. Our rate of fusion compares favorably with prior series using other methods of fixation.”

Journal Abstract

Purpose
To study the results of using a small, headless compression screw (AcuTwist) for thumb interphalangeal (IP) joint and finger distal interphalangeal (DIP) joint arthrodeses.

Methods
Between November 2007 and January 2012, 48 primary arthrodeses of the thumb IP joint or DIP joint in the other digits were performed in 29 consecutive patients with AcuTwist devices. Indications for arthrodesis included 19 cases of osteoarthritis in 25 fingers, 3 cases of lupus in 9 fingers, 2 cases of post-traumatic osteoarthritis in 2 fingers, and 1 case and finger each of acute trauma, neuromuscular disorder, postinfectious osteoarthritis, boutonniere deformity, and Dupuytren contracture. Charts were reviewed for clinical data, and radiographs were assessed for alignment and healing.

Results
Age averaged 59 years and follow-up averaged 12 months (range, 2–50 mo). Union occurred in 43 out of 46 fingers (94%). There were no cases of nail deformity, wound complications, tip hypersensitivity, or clinically notable malalignment. Three arthrodesis failed to fuse, including 2 asymptomatic nonunions and 1 fixation loss requiring revision with autograft. The complication rate was 9%.

Conclusions
Distal digital joint arthrodesis with the AcuTwist resulted in a fusion rate of 94% with a complication rate of 9%. Our rate of fusion
compares favorably with prior series using other methods of fixation.

Reference

Cox C, Earp BE, Floyd WE, Blazar PE. Arthrodesis of the thumb interphalangeal joint and finger distal interphalangeal joints with a headless compression screw. J Hand Surg Am. 2014;39(1):24-28.