Fixation of Metacarpal Shaft Fractures: Biomechanical Comparison of Intramedullary Nail Crossed K-Wires and Plate-Screw Constructs

Determining the Optimal Intramedullary Screw Canal Fill Ratio in Length Unstable Metacarpal Fractures: A Biomechanical Investigation

PURPOSE

Intramedullary (IM) screw fixation is gaining popularity in the treatment of metacarpal fractures. Despite its rapid adoption, there is a paucity of evidence regarding parameters to optimize effectiveness. This study aimed to quantify the relationship between stability, IM screw size, and canal fill using a cadaveric model.

METHODS

Thirty cadaveric metacarpals (14 index, 13 middle, and three ring fingers; mean age: 58.3 years, range: 48-70) were selected to allow for canal fill ratios of 0.7-1.1 for screws sized 3.0, 3.5, and 4.5 mm. Metacarpals underwent a 45° volar-dorsal osteotomy at the midpoint before fixation with an IM screw. Specimens were subjected to 100 cycles of loading at 10 N, 20 N, and 30 N before load-to-failure testing. Correlation coefficients for angular displacement on the final cycle at each load, peak load to failure, and average stiffness were assessed.

RESULTS

Correlation coefficients for the angular displacement on the 100th cycle were as follows: 10 N, R = 0.62, 20 N, R = 0.57, and 30N, R = 0.58. Correlation values for peak load to failure as a function of canal fit were as follows: 3.0 mm, R = 0.5, 3.5 mm, R = 0.17, and 4.5 mm, R = 0.44. The canal fill ratio that intersected the line-of-best fit at an angular deformity of 10° was 0.74. Average peak forces for 3.0-, 3.5-, and 4.5-mm screws were 79.5, 136.5, and 179.6 N, respectively. Average stiffness for each caliber was 14.8, 33.4, and 52.3 N/mm.

CONCLUSIONS

Increasing screw diameter and IM fill resulted in more stable fixation, but marginal gains were seen in ratios >0.9. A minimum fill ratio of 0.74 was sufficient to withstand forces of early active motion with angular deformity <10°.

CLINICAL RELEVANCE

An understanding of the relationship of IM fill ratio of metacarpal screws to fracture stability may provide a framework for clinicians to optimally size these implants.

Intramedullary Nail Fixation for Metacarpal Fracture: A Case Report and Review of the Clinical and Biomechanical Evidence

We present two cases of complex metacarpal fractures treated with an intramedullary locking nail. This is an emerging fixation method that minimizes tissue insult, provides sufficient stability, and allows early mobilization. Locking nails accommodate the capture of fractured fragments in complex unstable patterns and provide longitudinal and rotational stability. The described intrafocal technique is intended to improve coaxial placement of the wire into the medullary canal.

Percutaneous transverse pinning for metacarpal fractures: a clinical trial

INTRODUCTION

Metacarpal fractures account for 25%-50% of all hand fractures and may negatively impact hand function and ability to work. Percutaneous transverse pinning of non-articular metacarpal fractures allows mobilisation immediately after the procedure.

METHODS

Between March 2017 and February 2022, 56 patients undergoing percutaneous transverse pinning for unstable metacarpal fractures were prospectively recruited. We investigated surgical outcomes in terms of Patient-rated Wrist/Hand Evaluation (PRWHE) and pre-and post-operative radiographic evaluation. The Student t-test was used to compare the means of PRWHE values after surgery. Statistical significance was set at p < 0.05.

RESULTS

The mean age was 40.21 ± 17.9 years (range of 16 to 86 years). The average operating time was 27.96 min. The mean follow-up period was 14.3 ± 6.4 months (from 2 to 41 months). The mean PRWHE score was 6.5 ± 1.8. None of the patients had clinically observable rotational deformities, and the functional outcomes were satisfactory.

CONCLUSION

Percutaneous transverse pinning for non-articular metacarpal fractures restores excellent function, and imaging results are satisfactory. Further high-quality clinical trials are required to validate these results on a larger scale.

LEVEL OF EVIDENCE

II, prospective cohort study.

Comparison Between Intramedullary Nail and Percutaneous Pin Fixation in Proximal Phalanx Fractures

BACKGROUND

Percutaneous pinning has been the predominant technique for fixation of proximal phalanx fractures, but stiffness is a reported complication. The introduction of intramedullary (IM) nail fixation of proximal phalanx fractures provides a stronger biomechanical fixation for amenable fracture patterns with the added benefit of not tethering the soft tissue. The goal of this study was to compare the surgical outcomes of IM nail and percutaneous pin fixation in isolated proximal phalanx fractures.

METHODS

A retrospective review was performed at our institution between the years 2018 and 2022 for patients treated for proximal phalanx fractures. Patients that underwent fixation with IM nails or percutaneous fixation for isolated extraarticular proximal phalanx fractures were included. Patients were excluded if they had concomitant hand fractures, tendon injury, or intraarticular extension.

RESULTS

A total of 50 patients were included in this study. Twenty-eight patients received percutaneous pin fixation, and 22 patients underwent IM nail or screw fixation. There was no significant difference in injury patterns or demographics between these two groups. Patients that underwent IM nail fixation had a significantly quicker return to active motion, shorter duration of orthosis treatment, and fewer occupational therapy visits. In addition, patients in the IM fixation group had significantly improved range of motion (ROM) at 6 weeks postoperatively.

CONCLUSIONS

This study demonstrates that patients receiving percutaneous pin or IM nail fixation have equivocal union and complication rates. The IM nail fixation group was able to have quicker return to mobilization, fewer required occupational therapy visits, and improved early ROM.

Treatment of two or more metatarsal fractures

INTRODUCTION

Metatarsal fractures are the most common type of foot fracture. When surgical treatment is needed, pinning is typically used, either percutaneous or open. However, this fixation method has been criticized by some authors who lament residual malunion and prefer to use plate and/or screws. The primary objective of our study was to compare the outcomes of K-wire versus plate and/or screw fixation for the surgical treatment of two or more metatarsal fractures. The secondary objective was to evaluate the factors that contribute to poor outcomes and complications. We hypothesized that plate and/or screw fixation will produce better functional outcomes than K-wire fixation.

MATERIALS AND METHODS

This was a prospective and retrospective multicenter study carried out between 1 January 2010 and 1 June 2018 with a minimum follow-up of 12 months. Three functional scores were determined (AOFAS, FAAM and SF12 physical and mental) preoperatively, postoperatively and at the final assessment. We evaluated the outcomes in the entire study population and in four injury type subgroups, including one with isolated metatarsal fractures to control analysis bias.

RESULTS

Our analysis compiled data from 165 patients (123 men, 42 women) who had a mean age of 38 years (16-82). The mean follow-up time was 27.9months (10-120). There were no complications in 130 patients (79%). Skin necrosis occurred in 25 patients (15%). The FAAM score was significantly higher in the plate and/or screw group 70.2 (17-84) versus 60.3 (31-84) in the K-wire group (P=0.033). The 78 (19-100) AOFAS was higher, but not significantly, in the plate and/or screw group versus 70 (12-100) in the K-wire group (P=0.144).

CONCLUSION

Trauma to the foot that causes a fracture in two or more metatarsals often occurs due to a crush injury (39%). The frequency of associated bone lesions means that a preoperative CT scan should be done routinely to analyze the injury pattern and determine the best treatment. The fixation method should be adapted to the local conditions; when possible, it is preferable to use rigid fixation with plates and/or screws as it yields better functional outcomes.

LEVEL OF EVIDENCE

IV; study with retrospective component.

Metacarpal and Phalangeal Nonunions

The majority of phalangeal and metacarpal fractures will proceed to union when appropriately treated. However, when a nonunion does occur, it can lead to significant functional impairment for patients and societal costs. Operative intervention is typically required in these cases, but the technique can vary depending on each individual patient scenario. This article provides an overview of nonunions of the metacarpals and phalanges in the hand, including incidence, risk factors, current treatment options, and postoperative care.

Articular Involvement With Retrograde Headless Compression Screw Fixation of the Metacarpal

PURPOSE

Retrograde headless compression screw (RHCS) fixation for metacarpal fractures can lead to metacarpal head articular cartilage violation. This study aimed to quantify the articular surface loss after insertion of the RHCS and determine the functional range of motion (ROM) of the metacarpophalangeal (MCP) joint at the point of contact between the proximal phalangeal (P1) base and the articular defect.

METHODS

Ten fresh-frozen cadaveric hand specimens were analyzed for prefixation MCP joint ROM. After screw insertion, the ROM at which the dorsal portion of the P1 base begins to engage the screw tract defect, as well as the ROM at which the midsagittal portion of the P1 bisector engages the screw tract defect, was recorded. The distal axial articular surface of the metacarpal and the defects from screw insertion were measured using a digital image software program.

RESULTS

Nine men and one woman (mean age, 69 years) were examined. The prefixation mean extension-flexion arc for all MCP joints ranged from 1° to 85°. After screw insertion, the mean MCP ROM at which the dorsal P1 articular surface first engaged the screw tract was 31°. Only 7 digits had screw tract engagement with the midsagittal bisector of the P1 base at a mean flexion angle of -18° (18° hyperextension). Mean articular surface violation increased from the index finger moving ulnarly, with an average of 3.9% involvement.

CONCLUSIONS

Articular surface loss of the metacarpal head following RHCS insertion is negligible in a cadaveric model, with minimal engagement between the corresponding defect and the P1 base during functional ROM.

CLINICAL RELEVANCE

Retrograde headless compression screw fixation of metacarpals inevitably damages the cartilage. However, the actual defect is small in proportion to the articular surface area and not engaged during functional activity. These biomechanical features may mitigate the surgeon's concern about joint destruction, while ensuring the benefits of early rehabilitation and minimal invasiveness of this technique.

Biomechanical study of the fixation ability of the dorsal and volar locking plate for transverse metacarpal neck fractures

Metacarpal neck fracture is one of the most common types of hand fractures; the literature suggests that applying a bone plate on the dorsal side provides higher fixation strength than that provided by other fixation methods. However, bone plate fixation on the dorsal side may result in postoperative tendon adhesion. So far, no studies have investigated the fixation of metacarpal neck fractures on the volar side by using a bone plate. The objective of this study was to investigate the differences in the fixation results between bone plate fixation on the dorsal side and bone plate fixation on the volar side of the metacarpal in the case of a metacarpal neck fracture. A saw blade was used to create a transverse metacarpal neck fracture on 14 artificial metacarpal bone specimens. The specimens were divided into 2 groups depending on the fixation method: a volar locking plate (VLP) group and a dorsal locking plate (DLP) group. All specimens were subjected to a cantilever bending test on a material testing system, and a force-displacement curve was used to measure the yield force and stiffness, which served as an indicator of the fixation ability of the 2 fracture fixation methods. For the experimental results, the Mann-Whitney U test was used to compare the fixation abilities of the 2 fixation methods. In terms of yield force, the DLP group (266.9 ± 68.3 N) scored significantly higher than the VLP group (32.6 ± 2.7 N) (P < .05); expressed in terms of median, the DLP group scored 8.2 times higher than the VLP group. Similarly, in terms of stiffness, the DLP group (69.0 ± 13.4 N/mm, median ± interquartile range) scored significantly higher than the VLP group (12.9 ± 1.4 N/mm) (P < .05); expressed in terms of median, the DLP group scored 5.3 times higher than the VLP group. The fixation strength of volar bone plates is only about one-third of that of dorsal bone plates.

[Translated article] Closed reduction and intramedullary fixation of fifth metacarpal neck fractures: Retrograde vs. anterograde technique. Prospective study

INTRODUCTION

The fifth metacarpal fracture is a frequent pathology that can cause deformity and functional impairment for the adequate grip of the hand. Reintegration into daily or working activities is related to the treatment received and rehabilitation. In fractures of the neck of the fifth metacarpal, internal fixation with a Kirschner's wire is a conventional treatment method with variants that affect its outcome.

AIM OF THE STUDY

To compare the functional and clinical results of the treatment of fifth metacarpal fracture with the use of retrograde vs. antegrade Kirschner wires.

MATERIAL AND METHODS

Comparative, longitudinal, prospective study at a third-level trauma centre in patients with a fifth metacarpal neck fracture, with clinical, radiographic and Quick DASH scale follow-up at the 3rd, 6th, and 8th postoperative week.

RESULTS

Sixty patients were included (58 men, 2 women), age of 29.63±10.15 years, with a fifth metacarpal fracture, treated by closed reduction and stabilisation with a Kirschner wire. The antegrade approach showed a metacarpophalangeal flexion range at 8 weeks of 89.11° (p<0.001; 95% CI [-26.81; -11.42]), a DASH scale value of 18.17 (p<0.001; 95% CI [23.45; 39.12]), and an average of 27.35 days to return to work (p=0.002; 95% CI [16.22; 62.14]), compared with the retrograde approach.

CONCLUSION

Stabilisation with antegrade Kirschner wire showed superior functional results, and metacarpophalangeal range of motion, compared to those operated via retrograde approach.

Closed reduction and intramedullary fixation of fifth metacarpal neck fractures: Retrograde vs. anterograde technique. Prospective study

INTRODUCTION

The fifth metacarpal fracture is a frequent pathology that can cause deformity and functional impairment for the adequate grip of the hand. Reintegration into daily or working activities is related to the treatment received and rehabilitation. In fractures of the neck of the fifth metacarpal, internal fixation with a Kirschner's wire is a conventional treatment method with variants that affect its outcome.

AIM OF THE STUDY

To compare the functional and clinical results of the treatment of fifth metacarpal fracture with the use of retrograde versus antegrade Kirschner wires.

MATERIAL AND METHODS

Comparative, longitudinal, prospective study at a third-level trauma center in patients with a fifth metacarpal neck fracture, with clinical, radiographic and Quick DASH scale follow-up at the 3rd, 6th, and 8th postoperative week.

RESULTS

Sixty patients were included (58 men, 2 women), age of 29.63±10.15 years, with a fifth metacarpal fracture, treated by closed reduction and stabilization with a Kirschner wire. The antegrade approach showed a metacarpophalangeal flexion range at 8 weeks of 89.11° (p<0.001; 95% CI [-26.81; -11.42]), a DASH scale value of 18.17 (p<0.001; 95% CI [23.45; 39.12]), and an average of 27.35 days to return to work (p=0.002; 95% CI [16.22; 62.14]), compared with the retrograde approach.

CONCLUSION

Stabilization with antegrade Kirschner wire showed superior functional results, and metacarpophalangeal range of motion, compared to those operated via retrograde approach.

Intramedullary Metacarpal Fracture Fixation: A Biomechanical Study of Screw Diameter and Comparison With Intramedullary Wire Stabilization

PURPOSE

Interest in intramedullary metacarpal fracture fixation (IMFF) with screws is increasing. However, the optimal screw diameter for fracture fixation is not yet established. In theory, larger screws should be more stable, but there is concern about long-term sequelae of larger metacarpal head defects and extensor mechanism injury created during insertion as well as implant cost. Therefore, the purpose of this study was to compare different diameter screws for IMFF to a popular and more cost-effective alternative of intramedullary wiring.

METHODS

Thirty-two cadaveric metacarpals were used in a transverse metacarpal shaft fracture model. Treatment groups consisted of IMFF with 3.0 × 60 mm, 3.5 x 60 mm, and 4.5 x 60 mm screws as well as 4 1.1-mm intramedullary wires. Cyclic cantilever bending was performed with the metacarpals mounted at 45° to simulate physiologic loading. Cyclical loading at 10, 20, and 30 N was performed to determine fracture displacement, stiffness, and ultimate force.

RESULTS

At 10, 20, and 30 N of cyclical loading, all screw diameters tested provided similar stability as measured by fracture displacement and were superior to the wire group. However, ultimate force under load to failure testing was similar between the 3.5- and 4.5-mm screws and superior to 3.0-mm screws and wires.

CONCLUSIONS

For IMFF, 3.0, 3.5, and 4.5-mm diameter screws provide adequate stability for early active motion and are superior to wires. When comparing the different screw diameters, 3.5- and 4.5-mm diameter screws offer similar construct stability and strength superior to the 3.0-mm diameter screw. Therefore, to minimize metacarpal head morbidity, smaller screw diameters may be preferable.

CLINICAL RELEVANCE

This study suggests that IMFF with screws is biomechanically superior to wires in cantilever bending strength in the transverse fracture model. However, smaller screws may be sufficient to permit early active motion while minimizing metacarpal head morbidity.

A Biomechanical Comparison of Fixation Techniques in Metacarpal Shaft Fractures

Background  Typically, metacarpal shaft fractures are treated with closed reduction percutaneous pinning, intramedullary nails, or plate fixation. Recently some surgeons have begun using intramedullary headless compression screws. Questions/Purposes  The purpose of this study was to compare intramedullary screw fixation to K-wire fixation, which is the standard of care in a transverse metacarpal midshaft fracture, using a cadaveric model. Our hypothesis was that intramedullary screw fixation would have a biomechanical advantage (higher stiffness and peak load to failure) when compared with dual Kirschner wire fixation of transverse metacarpal shaft fractures. Methods  Four-point bend testing was performed to compare stiffness and failure load values of seven paired 2nd and 3rd metacarpals instrumented with headless intramedullary compression screw fixation or Kirschner wire fixation. Similar testing was performed on 14 unpaired 4th metacarpals. Results  There was no significant difference in peak load ( p  = 0.60) or stiffness ( p  = 0.85) between fixation groups for the 2nd and 3rd instrumented metacarpals. For the instrumented 4th metacarpals, there was no significant difference in peak load ( p  = 0.14), but the stiffness was significantly greater ( p  = 0.01) for the compression screw group compared with the Kirschner wire fixation. Conclusions/Clinical Relevance  In this study, the load to failure was not different between the two fixation methods and likely both techniques can sustain physiologic loads needed for rehabilitation. The greater stiffness in the 4th metacarpal compression screw group may be related to the smaller canal morphology than in the 2nd and 3rd metacarpals. Larger diameter screws may be needed to obtain a better fit particularly in the 2nd and 3rd metacarpals.

Expanding the applications of intramedullary cannulated screw fixation in the hand

OBJECTIVES

Intramedullary cannulated headless compression screw fixation (ICHCS) is gaining popularity for managing metacarpal and phalangeal fractures, but is still relatively new to the surgical landscape. We aim to further illustrate its utility and versatility by presenting the outcomes of such fractures treated with ICHCS at two tertiary plastic surgery centres. Primary objectives were to assess functional range of motion, patient-reported outcomes, and complication rates.

MATERIALS AND METHODS

All patients with metacarpal or phalangeal fractures treated with ICHCS (n = 49) between September 2018 and December 2020 were retrospectively reviewed. Outcomes were active ranges of motion (TAM), QuickDASH scores (obtained via telephone), and complication rates. Two-tailed Student's t-tests evaluated differences between centres.

RESULTS

TAMs were available for 59% (n = 34/58) of fractures; 70.7% were metacarpal and 29.3% were phalangeal. The mean cohort metacarpal TAMs and phalangeal TAMs were 237.7° and 234.5°, respectively. QuickDASH scores were available for 69% (n = 34/49) of patients. The mean cohort score for metacarpal fractures was 8.23, and 5.13 for phalangeal. Differences between the two centres were statistically significant (p < 0.05). Two complications occurred, giving an overall complication rate of 3.45%.

CONCLUSION

Our results corroborate previous reports on ICHCS, further demonstrating its versatility and capacity to provide excellent outcomes. More prospective, comparative studies are needed to fully determine the suitability of ICHCS.

Ideal Length and Diameter for Intramedullary Screw Fixation of Metacarpal Fractures: A Biomechanical Study

Purpose

This biomechanical study evaluated the effect of intramedullary screw diameter and length relative to 3-point bending force and torsional force when used to stabilize metacarpal shaft fractures.

Methods

Transverse osteotomies were made in the proximal metacarpal shaft in 36 middle finger metacarpal fourth-generation composite Sawbones. To compare screw diameters, antegrade intramedullary screws of 30-mm length were placed in 6 metacarpals, which included 4.7-mm Acutrak 2, Standard Acutrak 2 (4.0 mm), and Mini-Acutrak 2 (3.5 mm) screws. To compare screw lengths, metacarpals were fixated with Standard Acutrak 2 screws of 26, 30, or 34 mm in length, with screw tips bypassing the osteotomy by 6, 10, or 14 mm, respectively. A 6 degrees of freedom robot was used for torsional and 3-point bending testing.

Results

Increasing screw diameter demonstrated significant differences in both 3-point bending and torsional strengths. Maximum torsional loads were 69 Ncm (4.7-mm Acutrak 2), 45 Ncm (Standard Acutrak 2), and 27 Ncm (Mini-Acutrak 2) (P < .05). Loads to failure in the 3-point bending tests were 916 N (4.7-mm Acutrak 2), 713 N (Standard Acutrak 2), and 284 N (Mini-Acutrak 2) (P < .05). Differing screw lengths demonstrated significant differences with maximum torsional loads when comparing the 26-mm screws (22 Ncm) with 30- and 34-mm screws (45 and 55 Ncm, respectively) (P < .05). The 3-point dorsal bending strengths were significantly different between the 26-mm screws (320 N) and 30- and 34-mm screws (713 N and 702 N, respectively) (P < .05).

Conclusions

The results demonstrated significantly higher torsional strength and resistance to 3-point bending with larger intramedullary screw diameters. Further, when selecting the intramedullary screw length, the screw tip should pass at least 10 mm beyond the fracture.

Clinical Relevance

This study provided biomechanical evidence to guide surgeons in selecting intramedullary screw diameter and length for treating metacarpal fractures.

Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study

BACKGROUND AND OBJECTIVE

Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels.

MATERIAL AND METHODS

We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15 mm in the other 15. In turn, in each group, five fractures were stabilized with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS.

RESULTS

Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74 N and 70.86 N, respectively) was found to be more stable than retrograde IMHCS one (32.72 N) (p = 0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52 N retrograde vs. 57.64 N trans-articular vs. 42.92 N intra-articular; p = 0.20).

CONCLUSIONS

Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

[Translated article] Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study

BACKGROUND AND OBJECTIVE

Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels.

MATERIAL AND METHODS

We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15mm in the other 15. In turn, in each group, five fractures were stabilised with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS.

RESULTS

Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74N and 70.86N, respectively) was found to be more stable than retrograde IMHCS one (32.72N) (p=0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52N retrograde vs. 57.64N trans-articular vs. 42.92N intra-articular; p=0.20).

CONCLUSIONS

Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

Threaded Intramedullary Nails Are Biomechanically Superior to Crossed K-wires for Metacarpal Neck Fractures

BACKGROUND

Intramedullary nail (IMN) fixation of metacarpal fractures is an alternative to Kirschner wire (K-wire) fixation. The goal of this study was to compare the biomechanical properties of K-wire fixation with a threaded IMN (InNate; ExsoMed, Aliso Viejo, California).

METHODS

The study design was based on previously described biomechanical models for evaluating metacarpal fractures. Sixteen fresh frozen small finger-matched and ring finger-matched pairs were randomized to either IMN or 0.045 in K-wire fixation after receiving a standardized neck osteotomy. Proper implant placement was confirmed with plain radiographs. Specimens then underwent loading in a 3-point bend configuration. Load to failure (LTF), stiffness, and fracture displacement were recorded. Mechanical failure was defined by a sharp change in the load-displacement curve.

RESULTS

Age, sex, sidedness (left or right), and digit (ring or small finger) were evenly distributed between groups. The IMN had a significantly higher LTF than K-wires (546 N vs 154 N, P < .001). The K-wire fixation demonstrated plastic deformation between 75 and 150 N. Intramedullary nail stiffness was higher than that of K-wires (155.89 N/mm vs 59.28 N/mm, P < .001).

CONCLUSIONS

When surgical fixation is indicated for metacarpal neck and shaft fractures, the threaded IMN is biomechanically superior to crossed K-wires with the application of 3-point bend.

Intramedullary Headless Screw Fixation of Metacarpal Fractures: A Radiographic Analysis for Optimal Screw Choice

Background: The purpose of this study was to investigate variations in radiographic metacarpal anatomy as it relates to intramedullary (IM) fixation of metacarpal fractures and to compare this anatomy with available headless screw dimensions. Methods: We radiographically analyzed posteroanterior and lateral (LAT) radiographs of 120 metacarpals across 30 patients without structural abnormalities. Primary outcomes included IM isthmus diameter, isthmus location, metacarpal cascade, and head entry point collinear with IM canal. Measurements were compared with a list of commercially available headless screws used for IM fixation. Results: The average largest isthmus diameter was in the small metacarpal (3.4 mm), followed by the index (2.8 mm), long (2.7 mm), and ring (2.7 mm) metacarpals. The average cascade angle between long and index, long and ring, and long and small metacarpals was 0°, 24°, and 27°, respectively. The appropriate head entry point ranged between 25% and 35% from the dorsal surface of the metacarpal head on a LAT view. The retrograde isthmus location of the index and long finger was 39.2 and 38.1 mm, respectively. Twenty-five screws from 7 manufacturers were analyzed with sizes ranging from 1.7 to 4.5 mm. Only 8 of 17 screws between 2.3 and 3.5 mm had a length range above 35 mm. Conclusions: Metacarpal head entry point and cascade angle can help identify the appropriate reduction with the guide pin starting point in the dorsal 25% to 35% of the metacarpal head. Surgeons should be mindful to choose the appropriate fixation system in light of the variations between metacarpal isthmus size, isthmus location, and available screw lengths.

Comparison of the fixation ability between lag screw and bone plate for oblique metacarpal shaft fracture

Background

For oblique metacarpal shaft fracture, if anatomical reduction is achieved through conservative cast immobilization rather than stable fixation, bone malrotation can easily occur, resulting in severe loss in hand prehensile function. However, whether bone plate fixation or only lag screw fixation is more preferable remains unclear. Few studies have evaluated whether screw fixation can provide biomechanical fixation strength similar to bone plate fixation.

Objective

We assessed the difference in fixation strength between fixtation with two lag screws and bone plate for oblique metacarpal shaft fractures.

Materials and methods

We created oblique metacarpal shaft fractures on 21 artificial bones and fixated them using (1) double lag screw (2LS group), (2) regular plate (RP group), or (3) locked plate (LP group). To obtain the force–displacement data, a cantilever bending test was conducted for each specimen through a material testing machine. One-way analysis of variance and a Tukey test were conducted to compare the maximum fracture force and stiffness of the three fixation methods.

Results

The maximum fracture force of the 2LS group (mean + SD: 153.6 ± 26.5 N) was significantly lower than that of the RP (211.6 ± 18.5 N) and LP (227.5 ± 10.0 N) groups (p < 0.001). However, no significant differences were discovered between the RP and LP groups. The coefficient of variation for the maximum fracture force of the 2LS group (17.3%) was more than twice as high as that of the RP (8.7%) and LP (4.4%) groups. In addition, the stiffness of the three fixation methods was similar.

Conclusion

Compared with bone plate fixation, double lag screw fixation yielded slightly lower maximum bearable fracture force but similar stiffness. Therefore, this technique could be used for treating oblique metacarpal shaft fractures. However, using double lag screw fixation alone is technically demanding and requires considerable surgical experiences to produce consistent results.

A comparison of intramedullary cannulated screws versus miniplates for fixation of unstable metacarpal diaphyseal fractures

We carried out a prospective randomized study to compare the clinical and radiological results of metacarpal diaphyseal fractures treated with retrograde intramedullary headless cannulated screws (IHCS) and plates. Fractures were fixed with IHCS in 34 patients (37 metacarpals) and locked miniplates in 35 patients (40 metacarpals). The mean age was 33 years (range 18-61) in the IHCS group and 32 years (range 17-68) in plate group. All patients were followed up for 1 year. All fractures in the IHCS group united but there was one nonunion in the plate group. At final follow-up, there was no significant difference between the groups in total active movement, visual analogue pain score, Disabilities of the Arm, Shoulder, and Hand score and grip strength, although the study was not sufficiently powered to exclude differences with certainty. IHCS is a safe and fast technique that is a good alternative to plate fixation in metacarpal diaphyseal fractures.Level of evidence: I.

Intramedullary Screw Fixation Comprehensive Technique Guide for Metacarpal and Phalanx Fractures: Pearls and Pitfalls

Background:

Phalangeal and metacarpal fractures are the second and third most common upper extremity fractures after distal radius fractures with varying methods of fixation techniques. Intramedullary screw fixation is an increasingly preferred method of fixation. Benefits include early range of motion, faster recovery, limited dissection, and reduced complications. Improper technique, which is readily avoidable, can lead to suboptimal results.

Methods:

A review of recent literature on current techniques aims to summarize the biomechanics of intramedullary screw fixation and outline appropriate technique of placing headless compression screws for metacarpal and phalangeal fractures.

Results:

We discuss through images and videos the indications, preoperative workup, and technical pearls and pitfalls to encourage surgeons to add this technique to their armamentarium and improve outcomes.

Conclusions:

intrameduallry screw fixation is a powerful option for metacarpal and phalanx fixation that allows rigid stability, enabling early return of function with excellent rates of union and total active motion. With knowledge of technical pearls presented in this article, common mistakes can be avoided to improve efficiency of screw placement and optimize patient outcomes.

Comparison of the fixation ability of headless compression screws and locking plate for metacarpal shaft transverse fracture

Metacarpal shaft fractures are common hand fractures. Although bone plates possess strong fixation ability, they have several limitations. The use of headless compression screws for fracture repair has been reported, but their fixation ability has not been understood clearly.This study aimed to compare the fixation ability of locked plate with that of headless compression screw for metacarpal fracture repair.A total of 14 artificial metacarpal bones (Sawbones, Vashon, WA, USA) were subjected to transverse metacarpal shaft fractures and divided into 2 groups. The first group of bones was fixed using locked plates (LP group), whereas the second group was fixed using headless compression screws (HC group). A material testing machine was used to perform cantilever bending tests, whereby maximum fracture force and stiffness were measured. The fixation methods were compared by conducting a Mann-Whitney U test.The maximum fracture force of the HC group (285.6 ± 57.3 N, median + interquartile range) was significantly higher than that of the LP group (227.8 ± 37.5 N; P < .05). The median of the HC group was 25.4% greater. However, no significant difference in stiffness (P > .05) was observed between the HC (65.2 ± 24.6 N/mm) and LP (61.7 ± 19.7 N/mm) groups.Headless compression screws exhibited greater fixability than did locked plates, particularly in its resistance to maximum fracture force.

Comparison of clinical and radiological results of fixation methods with retrograde intramedullary Kirschner wire and plate-screw in extra-articular metacarpal fractures

OBJECTIVES

In this study, we aimed to compare clinical and radiographic outcomes of retrograde intramedullary Kirschner-wire (K-wire) fixation with those of plate-screw (PS) fixation.

PATIENTS AND METHODS

A total of 98 metacarpal shaft fractures in 75 patients (65 males, 10 females; mean age: 31.2±10.9 years; range, 16 to 65 years) were included between January 2011 and December 2017. The total joint active range of motion (AROM) and grip strength of the healthy and broken hands were evaluated. The Visual Analog Scale (VAS) and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores were recorded. We compared surgery duration, number of fluoroscopy images, and cost-effectiveness for each technique.

RESULTS

The overall mean follow-up was 21.9 (range, 12 to 56) months. At the last follow-up, total joint AROM (p=0.072), VAS score (p=0.298), QuickDASH score (p=0.132), and hand grip strength (p=0.947) were similar between the groups. Radiological union occurred in the PS and K-wire groups in a mean of 5.84 (range, 3 to 8) and 4.46 (range, 3 to 20) weeks, respectively (p=0.173). A significant difference was found in surgery duration (p=0.021) and number of fluoroscopy images (p<0.05) between the PS and K-wire groups. Two wound complications were observed in the PS group and one with K-wires.

CONCLUSION

Retrograde intramedullary K-wire fixation has certain advantages such as being less invasive and more accessible with shorter operation time, compared to PS fixation. Similar radiological and clinical scores can be obtained in patients undergoing retrograde intramedullary K-wire fixation or PS fixation.

Percutaneous reduction and fixation technique for 4th metacarpal shaft fracture

The objective of this retrospective study was to introduce a percutaneous reduction and intermetacarpal K-wire fixation technique for the treatment of the 4th metacarpal shaft fracture. From January 2014 to February 2017, 25 patients with isolated closed 4th metacarpal shaft fracture (angulation > 30°, rotation > 5°, or shortening > 5 mm) were treated by percutaneous reduction and internal fixation. Assessment comprised total active motion, grip strength, dorsal prominence, and patient satisfaction. Bone healing was achieved in all patients. At a mean follow-up of 28 months (range, 25-32 months), total active range of motion averaged 98% of contralateral values (range, 88%-100%). There were 20 excellent and 5 good results. Grip strength averaged 97% of contralateral values (range, 88%-100%). Mean dorsal prominence on a 100-mm visual analogue scale was 0 (range, 0-1). Mean satisfaction rating on the Short Assessment of Patient Satisfaction 26 (range, 22-28). Percutaneous reduction and intermetacarpal K-wire fixation is a useful technique for treating 4th metacarpal shaft fracture, achieving stable and reliable fixation, with good hand function.

Matched retrospective analysis of three different fixation devices for chevron osteotomy

Chevron osteotomy with consecutive fixation is a commonly performed operative treatment option for hallux valgus deformities. The present retrospective study aims to compare the clinical and radiological outcome of novel bioabsorbable magnesium screw fixation with metal screw and Kirschner wire fixation. Eighteen matched triplets were assembled according to the following criteria: female gender, age difference less than 5 years, date of operation within 4 months, difference in preoperative intermetatarsal angle less than 5°, and equal experience of the first and second surgeon. These patients, between 18 and 85 years of age and with a minimum follow-up period of 12 months, were invited to a follow-up examination, of which only 16 matched triplets of patients entirely kept the appointment. Thus, 48 feet of 44 patients were clinically evaluated using the American Orthopaedic Foot & Ankle Society scale, Foot Function Index, University of California and Los Angeles Activity Score, as well as a visual analogue scale for pain, satisfaction, cosmetic results, and functional impairment. Radiographical assessment included measuring intermetatarsal angle and first metatarsophalangeal angles. All occurring complications and revision surgeries were noted. Significant differences were observed for postoperative intermetatarsal angle between magnesium screw and pin fixation (p = 0.009). Moreover, patients receiving magnesium screw were significantly more prone to undergo the same procedure again (p = 0.03). In conclusion, if the advantages of bioabsorbable magnesium screws outweigh the drawbacks of increased costs and a higher surgical demand, this implant might serve as possible chevron osteotomy fixation method. Compression screws and Kirschner wires also show comparable satisfactory outcomes. LEVEL OF EVIDENCE: III retrospective comparative study.

Effect of a figure-of-eight cerclage wire with two Kirschner wires on fixation strength for transverse metacarpal shaft fractures: an in vitro study with artificial bone

BACKGROUND

Metacarpal shaft fractures are a common type of hand fracture. Despite providing strong fixation strength, plate fixation has numerous shortcomings. Concerning internal fixation with Kirschner wires (K-wires), although this approach is frequently used to treat metacarpal shaft fractures, the lack of functional stability may result in fixation failure.

OBJECTIVE

To evaluate the effect of figure-of-eight cerclage wire on fixation for transverse metacarpal shaft fractures using two K-wires.

MATERIALS AND METHODS

We used a saw blade to create transverse metacarpal shaft fractures in 14 fourth-generation artificial third metacarpal bones (Sawbones, Vashon, WA, USA), which were assigned to groups undergoing fixation with two K-wires (KP) or with two K-wires and figure-of-eight cerclage wire (KP&F8). All specimens were subjected to material testing, specifically cantilever bending tests. The maximum fracture force and stiffness of the two fixation types were determined on the basis of the force-displacement data. The Mann-Whitney U test was used to compare between-group differences in maximum fracture force and stiffness.

RESULTS

The maximum fracture force of the KP group (median ± interquartile range = 97.30 ± 29.70 N) was significantly lower than that of the KP&F8 group (153.2 ± 69.50 N, p < 0.05; Figure 5a), with the median of the KP&F8 group exceeding that of the KP group by 57.5%. Similarly, stiffness was significantly lower in the KP group (18.14 ± 9.84 N/mm) than in the KP&F8 group (38.25 ± 23.49 N/mm; p < 0.05; Figure 5b), with the median of the KP&F8 group exceeding that of the KP group by 110.9%.

CONCLUSION

The incorporation of a figure-of-eight cerclage wire increased the maximum fracture force and stiffness by 57.5 and 110.9%, respectively, compared with those achieved in standard two K-wire fixation. Therefore, hand surgeons are advised to consider the proposed approach to increase fixation strength.

A Single Intramedullary K-Wire Is Sufficient for the Management of Nonthumb Metacarpal Shaft Fractures

Objective

This study aims to evaluate the outcome after the internal fixation of diaphyseal metacarpal fractures by a single intramedullary K-wire.

Methods

In this prospective case series study, conducted from July 2017 to June 2019 in 23 adult patients with a single, unstable, diaphyseal metacarpal fracture, outcomes after internal surgical fixation using a single antegrade intramedullary K-wire were evaluated. The outcomes were evaluated by union rate, time to union, handgrip measurements at 6 and 12 months, and the modified Disabilities of the Arm, Shoulder, and Hand (DASH) score at 12 months.

Results

The study population consisted of 17 males and 6 females, with a mean patient age of 28.4 ± 8.5 years (range, 16–45 years). The median time to final follow-up was 14 ± 1.8 months (range: 12–24 months). The mean duration of the union was 7.3 ± 1.6 weeks (range: 5–11 weeks), with a union rate of 95.7% (22 cases). The mean handgrip strength was 68% ± 12.8% of the strength of the uninjured hand after 6 months and 92.7% ± 6.9% after 12 months. The mean modified DASH score was 2.6 ± 0.26 after 12 months (range: 0–5.8). There were no cases of malrotation or infection. In conclusion, using a single 1.8–2.0 mm K-wire gives excellent functional outcomes and union rate without significant complications when used to treat an unstable metacarpal shaft fracture.

Metacarpal shaft fixation: a biomechanical comparison of dorsal plating, lag screws, and headless compression screws

Background

Metacarpal shaft fractures are common and can be treated nonoperatively. Shortening, angulation, and rotational deformity are indications for surgical treatment. Various forms of treatment with advantages and disadvantages have been documented. The purpose of the study was to determine the stability of fracture fixation with intramedullary headless compression screws in two types of metacarpal shaft fractures and compare them to other common forms of rigid fixation: dorsal plating and lag screw fixation. It was hypothesized that headless compression screws would demonstrate a biomechanical stronger construct.

Methods

Five matched paired hands (age 60.9 ± 4.6 years), utilizing non-thumb metacarpals, were used for comparative fixation in two fracture types created by an osteotomy. In transverse diaphyseal fractures, fixation by headless compression screws (n = 7) and plating (n = 8) were compared. In long oblique diaphyseal fractures, headless compression screws (n = 8) were compared with plating (n = 8) and lag screws (n = 7). Testing was performed using an MTS frame producing an apex dorsal, three point bending force. Peak load to failure and stiffness were calculated from the load-displacement curve generated.

Results

For transverse fractures, headless compression screws had a significantly higher stiffness and peak load to failure, means 249.4 N/mm and 584.8 N, than plates, means 129.02 N/mm and 303.9 N (both p < 0.001). For long oblique fractures, stiffness and peak load to failure for headless compression screws were means 209 N/mm and 758.4 N, for plates 258.7 N/mm and 518.5 N, and for lag screws 172.18 N/mm and 234.11 N. There was significance in peak load to failure for headless compression screws vs plates (p = 0.023), headless compression screws vs lag screws (p < 0.001), and plates vs lag screws (p = 0.009). There was no significant difference in stiffness between groups.

Conclusion

Intramedullary fixation of diaphyseal metacarpal fractures with a headless compression screw provides excellent biomechanical stability. Coupled with lower risks for adverse effects, headless compression screws may be a preferable option for those requiring rapid return to sport or work.

Level of evidence

Basic Science Study, Biomechanics.

Effect of oblique headless compression screw fixation for metacarpal shaft fracture: a biomechanical in vitro study

Background

Metacarpal shaft fracture is a common fracture in hand trauma injuries. Surgical intervention is indicated when fractures are unstable or involve considerable displacement. Current fixation options include Kirschner wire, bone plates, and intramedullary headless screws. Common complications include joint stiffness, tendon irritation, implant loosening, and cartilage damage.

Objective

We propose a modified fixation approach using headless compression screws to treat transverse or short-oblique metacarpal shaft fracture.

Materials and methods

We used a saw blade to model transverse metacarpal neck fractures in 28 fresh porcine metacarpals, which were then treated with the following four fixation methods: (1) locked plate with five locked bicortical screws (LP group), (2) regular plate with five bicortical screws (RP group), (3) two Kirschner wires (K group), and (4) a headless compression screw (HC group). In the HC group, we proposed a novel fixation model in which the screw trajectory was oblique to the long axis of the metacarpal bone. The entry point of the screw was in the dorsum of the metacarpal neck, and the exit point was in the volar cortex of the supracondylar region; thus, the screw did not damage the articular cartilage. The specimens were tested using a modified three-point bending test on a material testing system. The maximum fracture forces and stiffness values of the four fixation types were determined by observing the force–displacement curves. Finally, the Kruskal–Wallis test was adopted to process the data, and the exact Wilcoxon rank sum test with Bonferroni adjustment was performed to conduct paired comparisons among the groups.

Results

The maximum fracture forces (median ± interquartile range [IQR]) of the LP, RP, HC, and K groups were 173.0 ± 81.0, 156.0 ± 117.9, 60.4 ± 21.0, and 51.8 ± 60.7 N, respectively. In addition, the stiffness values (median ± IQR) of the LP, HC, RP, and K groups were 29.6 ± 3.0, 23.1 ± 5.2, 22.6 ± 2.8, and 14.7 ± 5.6 N/mm, respectively.

Conclusion

Headless compression screw fixation provides fixation strength similar to locked and regular plates for the fixation of metacarpal shaft fractures. The headless screw was inserted obliquely to the long axis of the metacarpal bone. The entry point of the screw was in the dorsum of the metacarpal neck, and the exit point was in the volar cortex of the supracondylar region; therefore the articular cartilage iatrogenic injury can be avoidable. This modified fixation method may prevent tendon irritation and joint cartilage violation caused by plating and intramedullary headless screw fixation.

Single versus dual elastic nails for closed reduction and antegrade intramedullary nailing of displaced fifth metacarpal neck fractures

Closed reduction and internal fixation with antegrade intramedullary nails is a feasible and effective treatment for displaced fifth metacarpal neck fractures (FMNFs). The present study aimed to compare clinical and radiological outcomes in patients with displaced FMNFs after treatment with single or dual antegrade elastic intramedullary nails (AEIMNs). Thirty-three patients were treated with a single 2.0 mm AEIMN and 34 patients were treated with two 1.5 mm AEIMNs. Clinical and radiological outcomes included grip strength, active range of motion (ROM), active flexion and extension of the fifth metacarpophalangeal (MCP) joint, dorsal angulation loss, and metacarpal shortening of the fifth metacarpal at 12 months after treatment. No significant difference was observed between the two groups with respect to grip strength, ROM or flexion of the fifth MCP joint. The average values of dorsal angulation loss, metacarpal shortening, and extension of the fifth MCP joint of the dual nails group were better than those of the single nail group (dorsal angulation loss, 2.79 ± 1.93° vs. 4.05 ± 1.59°, P = 0.009; metacarpal shortening, 1.66 ± 0.80 mm vs. 2.12 ± 0.88 mm, P = 0.028; extension of the fifth MCP joint, 7.71 ± 4.43° vs. 4.82 ± 4.09°, P = 0.012). In conclusion, dual AEIMNs fixation provided better MCP extension and radiological outcomes than single AEIMN fixation.

Long-term outcomes of metacarpal fractures surgically treated using bioabsorbable plates: a retrospective study

Background

Implants made from bioabsorbable unsintered hydroxyapatite and poly-L-lactate composites (u-HA/PLLA) are widely used in the oral, maxillofacial, and orthopedic fields. This study assess the long-term (> 5 years) outcomes of patients with metacarpal fractures who were surgically treated using bioabsorbable plates and screws (Super-Fixsorb MX40 mesh; Teijin Medical Technology, Osaka, Japan).

Methods

A retrospective analysis of six patients with eight metacarpal fractures treated with bioabsorbable plates was done. All patients were followed for more than 5 years post-surgery. The clinical outcomes were evaluated using Q-DASH scores and the grip strength (GS): opposite side ratio. The resorption status of implants was assessed on plain computed tomography (CT) scans at final follow-up appointments.

Results

The mean age of the patients at the time of surgery was 29.5 years (16–54), and the median follow-up period was 81.8 months (68–101). All fractures united without displacement after an average of 3.5 months, and there were no implant specific complications associated with the use of absorbable plates. The mean grip strength ratio was 85.1% (56.8–104.5). The mean Q-DASH scores of 11.36 points (0–34.09) was good in all but two patients. We also observed that it took more than 8 years for the plates to be absorbed completely.

Conclusions

This study demonstrates that the process of bioabsorption in metacarpal fractures might be completed in about 8 years, and the absorption speeds were different inside and outside of the bone. The bioabsorbable plates are more cost-effective than metallic implants. The potential for bioabsorbable plates to be used in various clinical procedures is promising.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03841-x.

Intramedullary screw fixation for metacarpal shaft fractures: a biomechanical human cadaver study

Intramedullary cannulated compression screws have been introduced for the fixation of unstable metacarpal fractures. In the present study, this technique was compared with dorsal compression plating to evaluate its biomechanical performance in stabilizing metacarpal shaft fractures. In a first set of experiments, the biomechanical characteristics of the screws were analysed in an artificial bone model. In subsequent experiments, midshaft osteotomies were performed in human cadaver metacarpals, followed by plating or intramedullary screw osteosynthesis. The metacarpals were tested to failure in cantilever bending, following a stepwise increasing cyclic loading protocol. We found a significantly lower load at failure and a significantly lower number of cycles to failure in the intramedullary screw group, but both methods offered sufficient stability under these loads. With reference to published loads on the metacarpals during use of the hand, we conclude that intramedullary osteosynthesis yields sufficient strength and stiffness for early active motion. A difference in its fixation stability is noted compared with plate fixation, which may not be clinically relevant.

A novel method for internal fixation of basal fifth metatarsal fracture in athletes: a cadaveric study of the F.E.R.I. technique (Fifth metatarsal, Extra-portal, Rigid, Innovative)

Purpose

One of the main problems of Kirschner wire fixation of fifth metatarsal base fractures (in combination with a tension band wiring technique) seems to be hardware intolerance and several studies in athletes also report failure after isolated fixation with a screw only. These reports prompted us to look at new materials and a novel technique through fixation with an intramedullary screw combined with a high-resistance suture via the presented F.E.R.I. (Fifth metatarsal, Extra-portal, Rigid, Innovative) technique.

Methods

This cadaveric study describes F.E.R.I. technique. On a cadaver, through two mini portals, a full reduction and solid internal fixation with an intramedullary screw and suture cerclage with Fiberwire of a fifth metatarsal base fracture is achieved. In this article, the cadaveric study and proposed surgical technique are explained and illustrated step by step.

Results

The presented internal fixation F.E.R.I. technique is indicated in acute proximal fractures, stress fractures or non-union of metatarsal 5 (Zone 2–3 by Lawrence and Botte) and it resulted feasible and stable during manual stress test. The authors intend to study this technique in the clinical setting in the near future.

Conclusions

Fifth metatarsal base fractures gain specific interest when occurring in athletes. In this group of patients, internal fixation is often required to obtain a satisfactory outcome and time to return to play. The aim of the presented cadaveric study is to illustrate an innovative concept of internal fixation, named F.E.R.I.

Transverse and oblique fractures of the diaphysis of the fifth metacarpal: surgical outcomes for antegrade intramedullary pinning versus combined antegrade and retrograde intramedullary pinning

The purpose of this study was to develop a technique allowing a faster return to previous activities after surgical treatment of short transverse and oblique fractures of the diaphysis of the fifth metacarpal. It consisted of an anterograde and retrograde centromedullary double pinning connected. Our series included 40 patients of average age 25 years including 2 women. In 20 cases (group I), an anterograde centromedullary pinning with a 1.6- or 2-mm pin was performed followed by a 6-week orthosis and then 2-week self-education. In 20 cases (group II), an anterograde and retrograde centromedullary double pinning was performed using 2 1.5-mm pins connected by a connector (MétaHUS^®, Arex™). A first pin was introduced into the canal antegrade, then the second retrograde. The 2 externalized pins were connected, and self-rehabilitation was encouraged. Mean tourniquet time was 14.75 min (group I) and 15.8 min (group II), respectively. At the last follow-up, the average pain was 0.35/10 and 0.2/10, the Quick DASH 0.68/100 and 0.57/100, the strength of the hand 94.65% and 94.35%, the active flexion MCP 98.5% and 99%, respectively. MCP active extension was 98.5% and 98.75%; the sick leave was 8.4 and 6.3 weeks. All fractures healed without recovery with 3 complications: 2 infections on pins, in each group, 1 CRPS1 (group I). Our results seem to show that the technique of anterograde and retrograde centromedullary double pinning connected in the treatment of short transverse and oblique fractures of the diaphysis of the fifth metacarpal gives results at least as good as the reference technique with a non-negligible socioeconomic advantage, a less time off work.

Meta-bone Fracture Repair via Minimally Invasive Plate Osteosynthesis

A concise review of the history of meta-bone fracture repair is provided. The relevant surgical anatomy, available instrumentation, and execution of preoperative, intraoperative, and postoperative surgical care using minimally invasive plate osteosynthesis are discussed in detail. A short discussion that touches on future directions for care of meta-bone fractures follows.

Headless Screw Fixation of Metacarpal Neck Fractures: A Mechanical Comparative Analysis

BACKGROUND

The purpose of this study was to compare the mechanical properties of metacarpal neck fracture fixation by headless compression screw (HCS) with that of Kirschner wire (KW) cross-pinning and locking plate (LP) fixation.

METHODS

A metacarpal neck fracture was created in 30 fourth-generation composite Sawbones metacarpal models. A volar-based wedge was removed using a custom jig to simulate a typical apex dorsal fracture, unstable in flexion. The models were divided into 3 equal groups based on the method of fixation: retrograde cross-pinning with two 1.2-mm KWs, 2.0-mm dorsal T-plate with six 2.0-mm locking screws (LP), and a 3.0-mm retrograde HCS. Models were fixed at the proximal end, mounted in a material testing machine, and loaded through a cable tensioned over the metacarpal head, simulating grip loading. Cyclic loading from 0 to 40 N was performed, followed by loading to failure. Load, displacement, and failure mode were recorded.

RESULTS

Stiffness of the HCS (7.3 ± 0.7 N/m) was significantly greater than the KW (5.8 ± 0.5 N/m) but significantly less than the LP (9.5 ± 1.9 N/m). With cyclic loading to 40 N, the LP exhibited significantly less displacement (0.2 ± 1.3 mm) compared with the HCS (2.5 ± 2.3 mm) and KW (2.8 ± 1.0 mm). Load to failure for the HCS (215.5 ±3 9.0 N) was lower than that of the KW (279.7 ± 100.3 N) and of the LP (267.9 ± 44.1 N), but these differences were not statistically significant.

CONCLUSIONS

The HCS provided mechanical fracture fixation properties comparable with KW fixation. The LP construct allowed significantly less displacement and had the highest strength of the 3 fixation methods.

Closed Intramedullary Locking Nailing for Metacarpal Fractures: A Retrospective Study of Sixty-Six Fractures

Introduction: Metacarpal fractures are frequent injuries in the young male working population and the majority are treated non-operatively. There is a growing trend to surgically treat these fractures, with the aim of reducing the deformity and shortening the rehabilitation period. The aim of this retrospective case series is to report on our experience and clinical outcomes of using percutaneous flexible locking nails for the management of displaced metacarpal fractures. This study is a retrospective review of 66 fractures that were managed at our centre over a 7-year period.

Materials and Methods: Records of 60 patients were retrospectively reviewed. Indications for surgery were a displaced metacarpal shaft or neck fracture with associated rotational deformity, or multiple metacarpal fractures. The fracture was reduced by closed manipulation, and a flexible pre-bent locked intramedullary nail (1.6mm diameter) was inserted through a percutaneous dorsal antegrade approach, facilitated by a specially designed pre-fabricated awl. The implant was removed at union. Patients were followed-up in clinic until the fracture had united.

Results: The mean union time was seven weeks (range 2 to 22 weeks) and there were nine (14%) delayed unions (>3 months) and no non-unions. The nail had migrated in three cases (5%) and caused skin impingement in two cases (3%). There was one infected case (2%). Rotational clinical deformity was evident for two (3%) cases.

Conclusion: The use of a minimally-invasive locked intramedullary nailing for unstable metacarpal fractures has a significantly low complication rate, with predictable union times and good functional outcomes.

New fixation approach for transverse metacarpal neck fracture: a biomechanical study

Background

Fifth metacarpal neck fracture, also known as boxer’s fracture, is the most common metacarpal fracture. Percutaneous Kirschner-wire (K-wire) pinning has been shown to produce favorable clinical results. However, the fixation power of K-wires is a major concern. Plate fixation is also a surgical option, but it has the disadvantages of tendon adhesion, requirement of secondary surgery for removal of the implant, and postoperative joint stiffness. A fixation method that causes little soft tissue damage and provides high biomechanical stability is required for patients with fifth metacarpal neck fracture for whom surgical intervention is indicated. The present study proposed fixation using K-wires and a cerclage wire to treat fifth metacarpal neck fracture. The fixation power of this new method was compared with that of K-wires alone and plates.

Methods

We used a saw blade to create transverse metacarpal neck fractures in 16 artificial metacarpal bone specimens, which were then treated with four types of fixation as follows: (1) locking plate with five locking bicortical screws (LP group), (2) regular plate with five bicortical screws (RP group), (3) two K-wires (K group), and (4) two K-wires and a figure-of-eight cerclage wire (KW group). The specimens were tested by using cantilever bending testing on a material testing system. The stiffness of the four fixation types was determined by observing force–displacement curves. Finally, the Kruskal–Wallis test was adopted to process the data, and the Mann–Whitney exact test was performed to conduct paired comparison between the fixation types.

Results

The fixation strength levels of the four fixation approaches for treating fifth metacarpal neck fracture were ranked in a descending order of LP group (24.6 ± 5.1 N/mm, median ± interquartile range) > RP group (22.2 ± 5.8 N/mm) ≅ KW group (20.1 ± 3.2 N/mm) > K group (16.9 ± 3.0 N/mm).

Conclusion

The fixation strength of two K-wires was significantly higher when reinforcement was provided using a figure-of-eight cerclage wire. The strength of the proposed approach is similar to that of a regular plate with five bicortical screws but weaker than that of a locking plate with the same amount of bicortical screws. Cerclage wire-integrated K-wires can be an alternative method that avoids the excessive soft tissue dissection required for plating in open reduction internal fixation for fifth metacarpal neck fracture.

Union Rate and Rate of Hardware Removal Following Plate Fixation of Metatarsal Shaft and Neck Fractures

BACKGROUND

There have been very few studies related to the treatment of first, second, third, and fourth (MT) metatarsal shaft and neck fractures. In order to reduce metatarsal fracture malunion, many surgeons have turned from K-wire to plate fixation of these fractures. This study reports the healing rates, final fracture angulation, and need for hardware removal of operatively treated first to fourth MT shaft and neck fractures with plate fixation.

METHODS

A retrospective review was performed on all metatarsal fractures at our institution between 2008 and 2014 to identify all first to fourth MT shaft and neck fractures. Medical records and radiographs were reviewed for evidence of union, sagittal, and coronal fracture angulation (degrees), time to full weight bearing, plate size, fracture location (neck vs shaft), and number of screws on each side of the fracture. Multiple linear regression analysis was used to make calculations of statistical significance.

RESULTS

Forty-five patients with a total of 75 first to fourth MT fractures treated with plate fixation were included in this study. All fractures went on to union and full weight bearing. The average time to union and time to full weight bearing was 10.9 ± 2 weeks and 7.5 ± 1.6 weeks, respectively. The average coronal and sagittal plane angulation was 3.9 and 2.2 degrees, respectively. Fractures located in the neck were found to have higher coronal plane angulation malunion compared with fractures in the shaft ( P = .019). No variable was found to be related to final sagittal plane angulation. No patient had a plate removed, and 26 of 27 of patients did not want to have the plate removed.

CONCLUSION

Metatarsal fractures fixed with plates had high rates of union and low final fracture angulation. No patient included in this study underwent hardware removal.

LEVEL OF EVIDENCE

Level III, comparative study.

The Use of Minilocked Plate for Management of Unstable Metacarpal Fractures

Objective This study aims to evaluate the use of minilocked plates in the treatment of the metacarpal fractures. Method A total of 30 patients of metacarpal fractures were treated by minilocked plates. Results Union was achieved in all patients. There were 27 (90%) patients having satisfactory results (excellent and good results) and 3 patients (10%) had poor results. Conclusion The use of minilocked plate is recommended for fixation of periarticular, comminuted, and osteoporotic metacarpal fractures that offer rigid fixation early mobilization, decreases the incidence of joints stiffness, and tendon adherence which maximized the hand function.

Intramedullary Fixation of Metacarpal Fractures Using Headless Compression Screws

Introduction The purpose of this study is to examine the clinical results of retrograde intramedullary headless screw (IMHS) fixation for metacarpal fractures. Methods A retrospective review was performed on 16 patients with 18 metacarpal fractures who underwent IMHS fixation at a single institution. The average age was 32 years. The indications for surgery included rotational malalignment (five patients), multiple metacarpal fractures (five patients), angular deformity (four patients), and shortening greater than 5 mm (two patients). The average length of follow-up was 19.4 weeks (median 10.2 weeks). Results Functional outcome was considered excellent in all patients with total active motion in excess of 240 degrees. Active motion was initiated within 1 week of surgery. No secondary surgeries were performed related to a complication of IMHS fixation. Conclusion IMHS fixation of metacarpal fractures is an efficacious treatment modality for patients with comminution, multiple fractures, malrotation, and those who require rapid mobilization. It obviates the need for immobilization or more extensive plate and screw fixation techniques with excellent clinical results.