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Introduction: Over the past years, different fixation techniques focused on rotational stability in order to increase stability and stimulate union rates. Additionally, extracorporeal shockwave therapy (ESWT) has gained importance in the treatment of delayed and nonunions. Purpose of this study was to compare the radiological and clinical outcome of two headless compression screws (HCS) and plate fixation in scaphoid nonunions, in combination with intraoperative high energy ESWT., Materials and Methods: Thirty-eight patients with scaphoid nonunions were treated by using a nonvascularized bone graft from the iliac crest and stabilization with either two HCS or a volar angular stable scaphoid plate. All patients received one ESWT session with 3000 impulses and energy flux per pulse of 0.41 mJ/mm 2 intraoperatively. Clinical assessment included range of motion (ROM), pain according to the Visual Analog Scale (VAS), grip strength, disability of the Arm Shoulder and Hand Score, Patient-Rated Wrist Evaluation Score, Michigan Hand Outcomes Questionnaire and modified Green O'Brien (Mayo) Wrist Score. To confirm union, a CT scan of the wrist was performed., Results: Thirty-two patients returned for clinical and radiological examination. Out of these, 29 (91%) showed bony union. All patients treated with two HCS compared to 16 out of 19 (84%) patients treated by plate showed bony union on the CT scans. The difference was not statistically significant. However, at a mean follow-up interval of 34 months, no significant differences could be found in ROM, pain, grip strength and patient-reported outcome measurements between the two HCS and plate group. Height-to-length ratio and capitolunate angle improved significantly in both groups compared to preoperative., Conclusions: Scaphoid nonunion stabilization by using two HCS or angular stable volar plate fixation and intraoperative ESWT results in comparable high union rates and good functional outcome. Due to the higher rate for a secondary intervention (plate removal), HCS might be preferable as first choice, whereas the scaphoid plate fixation should be reserved for recalcitrant (substantial bone loss, humpback deformity or failed prior surgical intervention) scaphoid nonunions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The treatment of unstable scaphoid fracture and nonunion remains a challenging problem for hand surgeons. Minimally invasive treatment has become the preferred method of treatment., Purpose: This study introduces the arthroscopic technique with two headless compression screws (HCS) fixation and distal radius bone grafting for the treatment of unstable scaphoid fracture and nonunion, aiming to evaluate its clinical and radiological outcomes., Methods: It was a retrospective study. From January 2019 to February 2021, a total of 23 patients were included in the current study. Among them, 13 patients with unstable scaphoid fracture underwent arthroscopic treatment with two HCS; 10 patients with scaphoid nonunion underwent arthroscopic treatment with two HCS and a distal radius bone graft. The range of motion of the wrist, visual analog scale (VAS), grip strength, the Modified Mayo Wrist Score (MMWS), the Patient-Rated Wrist Evaluation (PRWE) score, and the Disability of the Arm, Shoulder and Hand (DASH) score were collected at preoperatively and the final follow-up. A computed tomography scan of the wrist was performed on each patient to analyze for union and postoperative osteoarthritis during the follow-up period., Results: Significant improvement was only observed in wrist extension. Clinical outcomes including grip strength, VAS pain score, MMWS, PRWE score, and DASH score were significantly improved at the final follow-up. In the subgroup analysis, both patients stabilized with either two HCS or a distal radius bone graft and two HCS have improved clinical outcomes after surgery, respectively. All patients achieved union. No screw fixation failure occurred, and no other postoperative complication was observed in any of the patients., Conclusions: The arthroscopic technique with two-HCS fixation and distal radius bone grafting is a reliable and effective technique for the treatment of unstable scaphoid fracture and nonunion, providing satisfactory union rates and clinical outcomes., (© 2023. The Author(s).)

Background: There is evidence that interfragmentary fracture gap size may affect the compression achievable with a modern headless compression screw (HCS). This mechanical study compared the compression achieved by 3 commercial HCS systems through various fracture gaps: CAPTIVATE Headless (Globus Medical, Inc, Audubon, Pennsylvania), Synthes (DePuy Synthes, Westchester, Pennsylvania), and Acumed Acutrak 2 (Acumed LLC, Hillsboro, Oregon). Methods: Screws were inserted into a custom test fixture composed of polyurethane synthetic bone foam fragments, separated by a layer of easily compressible polyurethane foam simulating a fracture gap. Compression was measured after final insertion and countersinking. The effect of the interfragmentary fracture gap size on the compression generated was also investigated. Results: The CAPTIVATE Headless 3.0 mm screw (70.1 ± 5.7 N) and the Synthes 3.0 mm screw (64.9 ± 7.3 N) achieved similar compressive forces after final countersink. Similar comparisons were found for the CAPTIVATE Headless 2.5 mm and Synthes 2.4 mm screws, and the CAPTIVATE Headless 4.0 mm and Acutrak 2 Standard screws. The final compression of the CAPTIVATE Headless 2.5 mm and Synthes 2.4 mm screws was not significantly affected when the fracture gap was doubled from 2 to 4 mm, but was reduced significantly by 95.9% with the Acutrak 2 Micro screw. Conclusion: When comparing like-sized screws, the CAPTIVATE, Synthes, and Acutrak 2 HCS systems demonstrated similar potential compressive forces. However, compared with the CAPTIVATE Headless and Synthes HCS systems, which are inserted with a compression sleeve that is not gap distance-dependent, the Acutrak 2 HCS system demonstrated less compression when the simulated fracture gap size was increased to 4 mm.

Introduction: Scaphoid nonunion remains challenging for hand surgeons. Several treatment options are available such as: non-vascularized or vascularized bone grafting, with or without additional stabilization. In the last few decades, extracorporeal shockwave therapy (ESWT) has become an established procedure for treating delayed and nonunions. Purpose of this retrospective follow-up study was (a) to investigate union rate and clinical outcome of the different implants [either one/two headless compression screws (HCS) or a plate] and (b) union rate and clinical outcome using only surgery, or a combination of surgery and ESWT., Materials and Methods: The study included 42 patients with scaphoid nonunions of the waist with a mean follow-up of 52 months. All patients received a non-vascularized bone graft from the iliac crest and stabilization was achieved by using one, two HCS or a plate. ESWT was performed with 3000 impulses, energy flux density per pulse 0.41 mJ/mm 2 within 2 weeks after surgery. Clinical assessment included range of motion (ROM), pain according to the Visual Analog Scale (VAS), grip strength, Disability of the Arm Shoulder and Hand Score, Patient-Rated Wrist Evaluation Score, Michigan Hand Outcomes Questionnaire and modified Green O'Brien (Mayo) Wrist Score. In addition, each patient had a CT scan of the wrist., Results: A total of 33/42 (79%) patients showed union at the follow-up investigation. Patients treated with additional ESWT showed bony healing in 21/26 (81%) and without ESWT in 12/16 (75%). Patients that were stabilized using one HCS showed bony healing in 6/10 (60%), with two HCS 10/12 (83%) and by plate 17/20 (85%). The ESWT group had a significantly lower pain score according to the VAS and better modified Green O'Brien (Mayo) Score. No differences could be found in respect of ROM, grip strength, functional outcome score depending of which stabilization method was used., Conclusions: Stabilization of scaphoid waist nonunions with two HCS or plate showed higher union rates than a stabilization using only one HCS. In addition, ESWT combined with a nonvascularized bone graft from the iliac crest seems a suitable option for treating scaphoid nonunions.

Introduction: Fractures of the scaphoid account for the most commonly injured carpal bone. Minimally displaced fractures of the waist will heal in 85-90% when using a below elbow cast. However, fractures with displacement have a higher risk for nonunion. Therefore, open reduction and fixation with headless compression screws (HCS) have become the preferred method of treatment. The aim of this study was to compare the radiological and clinical outcome of unstable scaphoid B2 type fractures, stabilized using one or two headless compression screws., Patients and Methods: A total of 47 unstable scaphoid B2 type fractures were included in this retrospective follow-up study. Twelve patients were not accessable and three refused to attend follow-up checks. Therefore, a total of 32 patients were included in this study with a mean follow-up interval of 43 (12-81) months. Twenty-two patients were treated using one HCS and ten with two HCS. Clinical assessment included range of motion (ROM), pain according to the visual analogue scale (VAS), grip strength, Disability of the Arm, Shoulder and Hand Score, Patient-Rated Wrist Evaluation Score, Michigan Hand Outcomes Questionnaire and modified Green O'Brien Wrist Score. The follow-up study on each patient included a CT-Scan of the wrist which was analyzed for union, osteoarthritis, dorsiflexed intercalated segment instability and humpback deformity., Results: Radiologically, 29/32 (91%) of the scaphoid B2 type fractures showed union, 10/10 (100%) in the two HCS group and 19/22 (86%) in the one HCS group (p < 0.05). No significant differences could be found in respect to ROM, grip strength, VAS and scores between the groups. Screw removal was necessary in two patients in the two HCS group and one in the one HCS group., Conclusion: The unstable B2 type fractures of the scaphoid, when using two HCS without bone grafting is a safe method, shows a significantly higher union rate and equal clinical outcome compared to stabilization using only one HCS.

Purpose: Scaphoid fracture commonly occurs around the mid-third of the scaphoid, and non-union of this fracture has several treatment options. The authors performed autologous cancellous bone graft from the iliac crest and headless compression screw fixation for the treatment of Mack-Lichtman type II scaphoid waist non-union. The purpose of this study was to determine whether this procedure was effective in achieving bony union and restoration of alignment., Methods: Medical records and radiographs of 30 patients who underwent cancellous bone graft and headless compression screw fixation for non-union of scaphoid waist fracture were retrospectively reviewed. There were 28 men and 2 women, with a mean age of 32.8 years (range: 21-63). The mean time to surgery was 10 months (range: 3-25) and mean follow-up was 37.5 months (range: 15-52). The authors analyzed bony union, lateral intrascaphoid angle, scapholunate angle, radiolunate angle and scaphoid length on radiographs and evaluated the Modified Mayo wrist score (MMWS) as a functional outcome., Results: Bony union was achieved in all cases. The lateral intrascaphoid angle improved from 40° to 32° (P<0.001). The scapholunate angle also improved from 61° to 56° (P=0.009). The radiolunate angle decreased from 8° to 4° (P=0.048) and scaphoid length increased from 22mm to 26mm (P<0.001) postoperatively. Wrist motion and MMWS improved significantly at last follow-up. However, there were no significant differences between scaphoid deformity correction angle and pre- to post-operative difference in MMWS., Conclusions: Non-structural autologous cancellous bone graft from the iliac crest and headless screw fixation provided reliable results and can be one of the effective treatment options for patients with symptomatic Mack-Lichtman type II non-union in the mid-third of the scaphoid., Level of Evidence: Level III., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: The literature describes the treatment of scaphoid fractures comparing the volar and dorsal approaches, the advantages and disadvantages of percutaneous screw fixation, as well as the treatment of scaphoid nonunions using different types of cancellous or corticocancellous bone grafts. Yet, to date no studies are available comparing the outcome of rotational stability in screw-fixed scaphoid fractures to angular stable systems. The purpose of this study is to provide reliable data about rotational stability in stabilised scaphoid fractures and to gain information about the rigidity and the stability of the different types of fixation., Methods: Three groups of different stabilisation methods on standardised scaphoid B2 fractures were tested for rotational stability. Stabilisation was achieved using one or two cannulated compression screws (CCS) or angular stable plating. We performed ten repetitive cycles up to 10°, 20° and 30° rotation, measuring the maximum torque and the average dissipated work at angle level., Results: Our study showed that rotational stability using a two CCS fixation is significantly (p < 0.05) higher than single CCS fixation. Using the angular stable plate system was also superior to the single CCS (p < 0.05). There was, however, no significant difference between two CCS fixation and angular stable plate fixation., Conclusion: Even though indications of using screws or plate systems might be different and plate osteosynthesis may be preferable in treatment of dislocated or comminuted fractures as well as for nonunions, our study showed a better rotational stability by choosing more than just one screw for osteosynthesis. Angular stable plating of scaphoid fractures also provides more rotational stability than single CCS fixation. The authors therefore hypothesise higher union rates in scaphoid fractures using more stable fixation systems.

To promote a quicker return to function, an increasing number of patients are treated with headless screws for acute displaced and even non-displaced scaphoid fractures. Therefore, it is imperative to understand and optimize the biomechanical characteristics of different implants to support the demands of early mobilization. The objective of this study was to evaluate the biomechanical fixation strength of 4 headless compression screws under distracting and bending forces. The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple screws were tested using a polyurethane foam scaphoid fracture model. Implants were inserted into the foam blocks across a linear osteotomy. Custom fixtures applied pull-apart and four-point bending forces until implant failure. Pull-apart testing was performed in three different foam densities in order to simulate osteoporotic, osteopenic, and normal bone. The peak pull-apart forces varied significantly between implants and were achieved by (from greatest to least): the Acutrak Standard, Synthes 3.0, Acutrak Mini, and Herbert-Whipple screws. The fully threaded screws (Acutrak) failed at their proximal threads while the shanked screw (Synthes and Herbert Whipple) failed at their distal threads. Similarly, the screws most resistant to bending were (from greatest to least): the Acutrak Standard, Acutrak Mini, Herbert-Whipple, and Synthes. Although the amount of force required for pull-apart failure increased with each increasing simulated bone density (a doubling in density required triple the amount of pull apart force), the mode and sequence of failure was the same. Overall, the fully threaded, conical design of the Acutrak screws demonstrated superior fixation against pull-apart and bending forces than the shanked designs of the Synthes and Herbert-Whipple. We also found a strong relationship between simulated bone density and pull-apart force., (Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.)

Introduction: An interpositional wedge bone graft is a procedure performed to restore carpal height and scaphoid length for displaced scaphoid nonunions with carpal instability. The purpose of this study was to investigate which headless screw design (threadless central shaft screw or fully threaded variable pitch compression screw) is biomechanically preferred when an interpositional bone graft is needed., Methods: A total of 24 cadaveric scaphoid interpositional bone grafts were divided into three groups and fixed with HCS 3.0, Herbert-Whipple or Acutrak mini-screws, and the relative biochemical stability of each was measured. The specimens were tested using an Instron tensile testing machine to calculate stiffness and load to failure. To measure compression forces at different interfragmentary gaps, 30 interpositional polyurethane bone graft models were generated with three pieces of cancellous sawbone block, and two custom-made load-cells were inserted in each gap. The models were then divided into three groups and fixed with the above screw types. The compression forces at different interfragmentary gaps were measured immediately and 30 min after screw fixation., Results: The average stiffness and load to failure were similar among the three groups (p>0.05). The average compression force measured at each interfragmentary gap was highest in the HCS 3.0 fixation group, followed by the Herbert-Whipple and Acutrak mini-screw fixation groups both immediately after screw fixation and after 30 min (at which time there were significant decreases in force). The compression forces measured at different interfragmentary gaps were almost identical in the HCS 3.0 and Herbert-Whipple screw fixation groups; however, the force measured at the leading side was significantly lower than that measured at the trailing side in the Acutrak mini-screw fixation group., Conclusion: The threadless central shaft screw design is biomechanically preferred over the fully threaded variable pitch screw design because it achieves higher and identical compression forces at different interfragmentary gaps with similar stiffness and load to failure., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Purpose: To evaluate the functional and radiographic results of a scaphoid excision and four-corner arthrodesis technique using percutaneous headless compression screws. Methods: A cohort of 33 patients, mean age 51 (range, 20–72) years, was treated for scapholunate advanced collapse (19), scaphoid nonunion advanced collapse (12), midcarpal instability (1), and Preiser disease (1). After scaphoid excision and removal of cartilage and subchondral bone in the midcarpal joint through a limited arthrotomy, capitolunate fixation was achieved with a percutaneous, transmetacarpal Acutrak screw (Acumed LLC, Hillsboro, OR), and triquetrohamate fixation was done with a percutaneous screw. Scaphoid was used as a bone graft. The average follow-up time was 8 months (n = 32; range, 6–64 mo). Results: Union occurred in 31 of 33 wrists (94%). One of the 33 patients had total wrist arthrodesis. Average total active flexion-extension arc was 71° after surgery and 83° before surgery. The postoperative carpal height averaged 0.47 compared to preoperative values of 0.45. The percentage of grip strength significantly improved from 41% before surgery to 80% after surgery. Postoperative mean verbal numerical rating scale pain score was less than 1, statistically better than the preoperative score of 7. Twenty-five of 33 patients were completely pain free. The average postoperative Mayo wrist score was 74, a significant improvement over the preoperative average of 40. Final Disabilities of the Arm, Shoulder, and Hand scores averaged 13 (n = 32; range, 0–49). Conclusions: These results were comparable to or better than the results of previously published techniques in terms of fusion rates, alleviation of pain, grip strength, range of motion; Mayo wrist score; and Disabilities of the Arm, Shoulder, and Hand questionnaire score. The technique exploits the theoretical advantages of strong compression between carpals while avoiding a screw-head sized hole in the lunate articular cartilage and preserving the dorsal capsular ligament attachments to the triquetrum. Type of study/level of evidence: Therapeutic IV. [Copyright &y& Elsevier]