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

Complications of osteosynthesis for long-finger metacarpal and phalanx fracture

Fractures of the metacarpals and phalanges represent a significant proportion of hand fractures. Although non-operative treatment is generally effective, some fractures require surgery. Historically, osteosynthesis using K-wires was widely used, but screw plates and then cannulated intramedullary screws have emerged as therapeutic alternatives. We assessed the complications associated with the different osteosynthesis techniques: stiffness, infection, bone consolidation and hardware-related problems. Each osteosynthesis technique has advantages and disadvantages, and choice depends on several factors. An individualized approach according to patient and fracture is essential to optimize clinical results.

Biomechanical analysis of plate versus K-wire fixation for metacarpal shaft fractures with wedge-shaped bone defects

BACKGROUND

Metacarpal shaft fracture is a common type of hand fracture. Numerous studies have explored fixing transverse fractures in the midshaft of the metacarpal bone. However, this section of the metacarpal bone is often susceptible to high-energy injury, resulting in comminuted fracture or bone loss. In such cases, wedge-shaped bone defects can develop in the metacarpal shaft, increasing the difficulty of performing fracture fixation. Notably, the research on this type of fracture fixation is limited. This study compared the abilities of four fixation methods to fix metacarpal shaft fractures with wedge-shaped bone defects.

METHODS

In total, 28 artificial metacarpal bones were used. To create wedge-shaped bone defects, an electric saw was used to create metacarpal shaft fractures at the midshaft of each bone. The artificial metacarpal bones were then divided into four groups for fixation. The bones in the first group were fixed with a dorsal locked plate (DP group), those in the second group were fixed with a volar locked plate (VP group), and those in the third group were fixed by combining dorsal and volar locked plates (DP + VP group), and those in the fourth group were fixed with two K-wires (2 K group). Cantilever bending tests were conducted using a material testing machine to measure yielding force and stiffness. The four groups' fixation capabilities were then assessed through analysis of variance and Tukey's test.

RESULTS

The DP + VP group (164.1±44.0 N) achieved a significantly higher yielding force relative to the 2 K group (50.7 ± 8.9 N); the DP group (13.6 ± 3.0 N) and VP group (12.3 ± 1.0 N) did not differ significantly in terms of yielding force, with both achieving lower yielding forces relative to the DP + VP group and 2 K group. The DP + VP group (19.8±6.3 N/mm) achieved the highest level of stiffness, and the other three groups did not differ significantly in terms of stiffness (2 K group, 5.4 ± 1.1 N/mm; DP group, 4.0 ± 0.9 N/mm; VP group, 3.9 ± 1.9 N/mm).

CONCLUSIONS

The fixation method involving the combined use of dorsal and volar locked plates (DP + VP group) resulted in optimal outcomes with respect to fixing metacarpal shaft fractures with volar wedge bone defects.

Metacarpal Shortening with Intramedullary Screw Fixation: A Cadaveric Study

Background  Intramedullary screw fixation is a commonly used technique for the management of metacarpal fractures. However, compression across the fracture site can lead to unintentional shortening of the metacarpal. Questions/Purposes  Our aim was to evaluate the risk of overshortening with differing intramedullary device designs for fixation of metacarpals. Methods  The small finger metacarpal of nine fresh-frozen cadavers were included. A metacarpal neck fracture was simulated with a 5-mm osteotomy. Three different intramedullary screw designs were compared. Each screw was placed in a retrograde fashion into the intramedullary canal and the amount of shortening measured. Screws were reversed and the number of reverse turns with the screwdriver needed to release overshortening were measured. Results  The average shortening at the osteotomy site was 2.5 mm. The mean shortening was 80%, 58%, and 12% for the partially threaded screw, fully threaded screw, and threaded nail, respectively. The mean differences of the distance shortened were statistically significant for the threaded nail compared with the partially and fully threaded screws. The partially threaded screw had the most shortening, while the threaded nail provided the least amount of shortening. When the screws were reversed, the screws did not disengage until the screw was fully removed from the osteotomy site. Conclusion  The fully threaded nail demonstrates less shortening and possibly minimizes overshortening of fractures compared with partially threaded and fully threaded screw designs. Overshortening cannot be corrected by unscrewing the screw unless completely removed from the distal fragment. Clinical Relevance  Orthopaedic surgeons may select intermedullary screws based on the design that is suited for the particular metacarpal fracture pattern.

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.

Intramedullary Threaded Nail Fixation Versus Plate and Screw Construct in Metacarpal Neck Fractures: A Biomechanical Study

BACKGROUND

Indicated surgical management of metacarpal neck fractures varies with techniques, including Kirschner wire fixation, plate fixation, intramedullary fixation, and headless compression screw fixation, without demonstrated superiority. This study compares intramedullary threaded nail (ITN) fixation with a locking plate construct.

METHODS

Index through small finger metacarpals were harvested from 10 embalmed cadavers. After application of appropriate exclusion criteria, remaining metacarpals underwent neck fracture creation by a three-point load to failure. Eight samples were randomly allocated to fixation with ITN fixation, and six were stabilized with a 2.3-mm seven-hole locking plate. Samples were then subjected to a second round of biomechanical testing using the same apparatus. Ultimate load between the intact tissue and the subsequently stabilized fracture was analyzed with a paired Student t -test. Percentage change in ultimate load in the intact tissue and stabilized tissue was calculated, and the magnitude of relative difference between the two groups was analyzed using unpaired Student t -tests. Statistical difference was defined by a P value of < 0.05.

RESULTS

Both groups demonstrated the ability to handle a biomechanical load; however, both were significantly weaker than the intact tissue (paired Student t -test p ITN-fixed versus p ITN-intact = 0.006; p plate-fixed versus p plate-intact = 0.002). ITN samples demonstrated a higher load to failure (unpaired Student t -test p ITN-fixed versus p plate-fixed = 0.039).

CONCLUSION

ITN provides a biomechanically stronger fixation constructed for vertically oriented metacarpal neck fractures compared with locking plate fixation. Both ITN and locking plate constructs provide stabilization capable of tolerating a biomechanical load; however, both fixation modalities are weaker than the native tissue.

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.

A Comparison of Outcomes following Plate versus Pin Fixation of Metacarpal Shaft and Neck Fractures

The aim of this study is to compare clinical and radiographic outcomes of open reduction and internal fixation versus closed reduction and percutaneous pinning of metacarpal fractures in relation to anatomic and surgical variables.

Methods

Electronic medical records at two institutions were reviewed for patients who underwent surgical intervention for metacarpal fractures. Data were collected from those who underwent reduction and internal fixation with either plates or Kirschner wires (K-wires). Inclusion criteria included minimum postoperative follow-up of 60 days and age 18 years or older. Exclusion criteria included insufficient radiographic data, previously attempted closed reduction with immobilization, pathologic fracture mechanism, history of previous trauma or surgery to the affected bone, and fixation technique other than plate or K-wire.

Results

We reviewed data for patients treated over a 22-year time period. Ultimately, 81 metacarpal shaft and neck fractures in 60 patients met inclusion criteria. Among all metacarpal fractures, complications were present in 39 (48.1%) cases. There were no significant associations between complication prevalence and hardware type. Revision surgery was required in 11 (13.6%) patients; there were no significant associations between revision procedures and hardware type. Postoperatively, all patients with imaging data had radiograph follow-up to assess union status. There was no significant association between time to union and hardware type.

Conclusions

Outcomes showed no significant difference between plate and pin fixation for metacarpal shaft and neck fractures. These findings suggest that surgeons may have flexibility to decide on the type of operative intervention while considering patient-specific factors, such as the need for early mobilization.

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.

Retrograde Intramedullary Screw Fixation for Metacarpal Fractures: A Systematic Review

Common forms of fixation of metacarpal fractures have historically included percutaneous Kirschner wire fixation, plates and screws, and, more recently, intramedullary screw fixation. Retrograde intramedullary screws (RISs) are a novel modality first described 10 years ago. The purpose of this review is to critically evaluate the published literature assessing outcomes of RIS fixation for metacarpal fractures and create a complication profile for this novel technique. A comprehensive literature search was performed using electronic databases for both clinical and biomechanical studies in relation to RIS fixation published from 2000 to 2020. A total of 19 studies (13 clinical and 6 biomechanical) met the inclusion criteria. The clinical studies examined 603 metacarpal fractures and demonstrated adequate functional outcomes in terms of grip strength, total active motion, and time to return to work. The biomechanical studies examined 80 metacarpal fractures, finding that load to failure in RISs was often equal to or higher than Kirschner wires but less than plate and screws. The complication rate in reviewed studies was 2.8%, with the most prevalent complications being stiffness and extension lag. RIS use in metacarpal fractures appears to provide adequate stability with satisfactory clinical outcomes and minimal complications, although more high-quality studies are needed to fully examine this modality.

Morphological Analysis of Metacarpal Shafts With Respect to Retrograde Intramedullary Headless Screw Fixation

Background: The use of retrograde intramedullary headless compression screw fixation for metacarpal neck and shaft fractures has been described in the literature. The purpose of this study was to perform a computed tomography (CT)-based morphological analysis of metacarpal size to help surgeons anticipate expected hardware needs. Methods: In all, 108 consecutive hand CT scans were evaluated for the medullary diameter in the volar-dorsal and radial-ulnar planes at the narrowest point of the canal, as well as for the distance from the articular surface to this point. Results were then analyzed by finger and by sex. Results: The ring finger had the smallest average medullary canal diameter for both men and women (2.7 and 2.6 mm, respectively); the small finger had the largest average diameter (3.9 mm) for men and the middle finger (3.6 mm) for women. Radial-ulnar was the rate-limiting dimension in the index, middle, and ring fingers, whereas volar-dorsal was the smallest dimension in the small finger, regardless of sex. Medullary diameter tended to be larger in patients aged more than 50 years. More than 50% of fingers have diameters >3.0 mm, and at least 40% of index, middle, and small fingers have diameters >3.5 mm, which are common diameters of commercially available headless compression screws. Conclusions: When preparing to perform open reduction internal fixation of a metacarpal using retrograde intramedullary headless compression screws, the surgeon needs to be prepared with screws of larger diameters to optimize fixation. Screws of larger diameters are needed to achieve endosteal purchase, regardless of sex.

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.

Analysis of 3 Different Operative Techniques for Extra-articular Fractures of the Phalanges and Metacarpals

Background: Several techniques have been described for treating metacarpal and phalangeal fractures. We sought to compare the 3 techniques most frequently used for extra-articular metacarpal and phalangeal fractures: plate screw (PS), Kirschner wire (KW), and retrograde intramedullary screw (RIS) fixation. We aimed to determine whether using an RIS provides better clinical outcomes than using either a PS or a KW fixation. Methods: We conducted a retrospective review of patients who underwent surgical treatment of metacarpal and phalangeal fractures from January 2011 to December 2017 in our department. Only patients with an acutely displaced short oblique or transverse extra-articular metacarpal or phalangeal fracture were included. Patients were classified into 3 groups depending on the treatment they received: PS, KW, or RIS fixation. The duration of each procedure was recorded. Clinical assessments included measuring total active motion (TAM), grip strength, and an evaluation of plain radiographs through to ultimate healing. A Disabilities of the Arm, Shoulder and Hand (QuickDASH) score was collected on all patients. Data were analyzed by analysis of variance or Kruskal-Wallis rank test, as indicated. Results: A total of 253 fractures (202 metacarpal and 51 phalangeal) in 230 patients were included in analysis. In all, 135 fractures (53.3%) underwent PS fixation; 53 (20.9%), KW fixation; and 65 (25.6%), RIS fixation. In the KW fixation group, Bouquet pinning was performed for metacarpal fractures and cross pinning for phalangeal fractures. When more than 1 fracture coexisted in the same patient, they were considered separate instances. No differences among the 3 groups were observed when evaluating mean time to radiological union, grip strength, TAM, or QuickDASH score. Mean surgery time was significantly shorter with KW (20 minutes) and RIS (25 minutes), than with PS (32 minutes). Mean return to work or routine activities time was significantly less in the RIS (7.8 weeks) group than in the PS and KW groups (8.3 and 9.2 weeks, respectively). Conclusions: Surgical treatment is recommended in patients with unstable metacarpal and phalangeal fractures. The use of RIS was associated with shorter mean surgery duration and return to work times than PS and KW, respectively.

Bone plate fixation ability on the dorsal and lateral sides of a metacarpal shaft transverse fracture

Background

Metacarpal shaft fractures are a common hand trauma. The current surgical fixation options for such fractures include percutaneous Kirschner wire pinning and nonlocking and locking plate fixation. Although bone plate fixation, compared with Kirschner wire pinning, has superior fixation ability, a consensus has not been reached on whether the bone plate is better placed on the dorsal or lateral side.

Objective

The purpose of this study was to evaluate the fixation of locking and regular bone plates on the dorsal and lateral sides of a metacarpal shaft fracture.

Materials and methods

Thirty-five artificial metacarpal bones were used in the experiment. Metacarpal shaft fractures were created using a saw blade, which were then treated with four types of fixation as follows: (1) a locking plate with four locking bicortical screws on the dorsal side (LP_D); (2) a locking plate with four locking bicortical screws on the lateral side (LP_L); (3) a regular plate with four regular bicortical screws on the dorsal side (RP_D); (4) a regular plate with four regular bicortical screws on the lateral side (RP_D); and (5) two K-wires (KWs). All specimens were tested through cantilever bending tests on a material testing system. The maximum fracture force and stiffness of the five fixation types were determined based on the force–displacement data. The maximum fracture force and stiffness of the specimens with metacarpal shaft fractures were first analyzed using one-way analysis of variance and Tukey’s test.

Results

The maximum fracture force results of the five types of metacarpal shaft fracture were as follows: LP_D group (230.1 ± 22.8 N, mean ± SD) ≅ RP_D group (228.2 ± 13.4 N) > KW group (94.0 ± 17.4 N) > LP_L group (59.0 ± 7.9 N) ≅ RP_L group (44.5 ± 3.4 N). In addition, the stiffness results of the five types of metacarpal shaft fracture were as follows: LP_D group (68.7 ± 14.0 N/mm) > RP_D group (54.9 ± 3.2 N/mm) > KW group (20.7 ± 5.8 N/mm) ≅ LP_L group (10.6 ± 1.7 N/mm) ≅ RP_L group (9.4 ± 1.2 N/mm).

Conclusion

According to our results, the mechanical strength offered by lateral plate fixation of a metacarpal shaft fracture is so low that even KW fixation can offer relatively superior mechanical strength; this is regardless of whether a locking or nonlocking plate is used for lateral plate fixation. Such fixation can reduce the probability of extensor tendon adhesion. Nevertheless, our results indicated that when lateral plate fixation is used for fixating a metacarpal shaft fracture in a clinical setting, whether the mechanical strength offered by such fixation would be strong enough to support bone union remains questionable.

Comparative analysis of the effects of AO mini-plate and Kirschner wire pinning in the metacarpal fractures: A retrospective study

The aim of this study was to investigate the clinical effect of AO miniplate screw internal fixation and Kirschner wire (KW) in the treatment of metacarpal fractures.We retrospectively analyzed the clinical data of 590 metacarpal fracture patients admitted to our hospital from March 2016 to March 2019. Among them, 290 patients were treated with KWs; 300 were treated with AO microplate internal fixation. The clinical, radiological results, time of surgery, and complications were observed and compared between the 2 groups.The imaging characteristics and preoperative fracture types of the 2 groups were similar and comparable (P > .05). The operation time, length of hospital stay, and fracture healing time of AO group were shorter than those of KW group, and the differences were statistically significant (41.22 ± 7.23 vs 25.64 ± 6.29; 7.13 ± 2.38 vs 5.26 ± 1.71; 67.43 ± 22.01 vs 52.57 ± 17.46, P < .05). In addition, the incidence of postoperative complications in AO group was lower than that in KW group (8.3% vs 15.2%, P < .05). In terms of surgical knuckle extension, flexion, and total mobility (compared with the uninjured hand), patients in the AO plate group were significantly improved compared with patients in the KW group, and the difference was statistically significant (4 vs 10 degree; 19 vs 10 degree; 14 vs 29 degree, P < .05); The average degree of finger rotation deformity in AO plate group was significantly lower than that in KW group (1 vs 6 degree, P < .05). In terms of grip strength (compared with the healthy hand), the average grip strength of AO plate group was significantly higher than that of KW group (93% vs 83%, P < .05). Patients in the OA plate group had a lower Disabilities of the Arm, Shoulder and Hand score (P < .05).Compared with KW fixation, AO mini-plate and screw fixation for the metacarpal fracture has a better effect, which can effectively shorten the operation time and reduce the trauma to patients. It can provide patients with better stability and realize the early movement of the palm, promote fracture healing and joint function recovery; it can reduce the incidence of postoperative complications, which has certain safety. In addition, it can effectively reduce the risk of poor finger rotation.

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.

Osteosynthesis of Fractures of the Metacarpal Neck with Self-Compressing Screw - Preliminary Analysis of 21 Cases

Objective  The present study aims to analyze the clinical results of the surgical treatment of metacarpal neck fractures with retrograde intramedullary fixation using cannulated headless screws (Herbert type).

Methods  Retrospective study of 21 closed fractures deviated from the metacarpal neck in 21 patients operated between April 2015 and November 2018.

Results  The sample included 19 men and 2 women. The mechanisms that caused the trauma were punching, falling to the ground and motor vehicle accident (n = 14, 5 and 2). The affected metacarpals were the 5 ^th , 3 ^rd , and 2 ^nd (n = 19, 1 and 1). Surgical indications were neck-shaft diaphysis of the metacarpal > 30° for the 2 ^nd and 3 ^rd metacarpals and > 40° for the 5 ^th metacarpal, shortening ≥ 5mm, rotational deviation, and the desire of the patient not to use plaster cast. In the immediate postoperative period, patients remained without immobilization and were instructed to mobilize their fingers according to tolerance. All patients had total active mobility > 240° and returned to their former occupations. All fractures consolidated and there were no reinterventions.

Discussion  The great advantages of the headless screw technique are its low morbidity, sufficient stability to avoid external immobilization, and reproducibility at low cost.

Conclusion  This is an easy, fast technique that has excellent results for the surgical treatment of displaced fractures of the neck of the metacarpals.

Osteosynthesis of Phalangeal Fractures: Biomechanical Comparison of Kirschner Wires, Plates, and Compression Screws

PURPOSE

The aim of this study was to compare several osteosynthesis techniques (intramedullary headless compression screws, T-plates, and Kirschner wires) for distal epiphyseal fractures of proximal phalanges in a human cadaveric model.

METHODS

A total of 90 proximal phalanges from 30 specimens (index, ring, and middle fingers) were used for this study. After stripping off all soft tissue, a transverse distal epiphyseal fracture was simulated at the proximal phalanx. The 30 specimens were randomly assigned to 1 fixation technique (30 per technique), either a 3.0-mm intramedullary headless compression screw, locking plate fixation with a 2.0-mm T-plate, or 2 oblique 1.0-mm Kirschner wires. Displacement analysis (bending, distraction, and torsion) was performed using optical tracking of an applied random speckle pattern after osteosynthesis. Biomechanical testing was performed with increasing cyclic loading and with cyclic load to failure using a biaxial torsion-tension testing machine.

RESULTS

Cannulated intramedullary compression screws showed significantly less displacement at the fracture site in torsional testing. Furthermore, screws were significantly more stable in bending testing. Kirschner wires were significantly less stable than plating or screw fixation in any cyclic load to failure test setup.

CONCLUSIONS

Intramedullary compression screws are a highly stable alternative in the treatment of transverse distal epiphyseal phalangeal fractures. Kirschner wires seem to be inferior regarding displacement properties and primary stability.

CLINICAL RELEVANCE

Fracture fixation of phalangeal fractures using plate osteosynthesis may have the advantage of a very rigid reduction, but disadvantages such as stiffness owing to the more invasive surgical approach and soft tissue irritation should be taken into account. Headless compression screws represent a minimally invasive choice for fixation with good biomechanical properties.

Fixation of Metacarpal Fractures Using Intramedullary Headless Compression Screws: A Tertiary Care Institution Experience

Introduction

Metacarpal fractures account for the majority of hand fractures. Inadequate management can cause functional deficit which can lead to loss of fine hand movements. Adequate management has proven to give good outcomes. The use of intramedullary screws has given better results than the use of Kirschner wires (K-wires).

Method

This study was conducted at Dr. Ruth Phau Civil Hospital, Karachi (CHK) between August 1, 2018 and January 31, 2019. A total of 32 patients presented with metacarpal fractures. They were surgically managed with intramedullary headless screw fixation. Post-operatively, grip strength, range of motion, and presence of any disabilities were recorded. Patients were followed up to three months.

Results

Out of 32 patients, six were females. Mean age was found to be 29.1 ± 10.5 years. Post-operatively the mean grip strength was found to be 37.8 ± 7.3 kilograms. The mean total active range of motion was found to be 242.8 ±14.5 degrees. The mean days to return back to work were 25 ± 5.4 days. The mean patient satisfaction score was 8.1 ± 0.79. Three patients developed post-operative stiffness of the joint.

Conclusion

Patients with intramedullary screw fixation have good post-operative results with early return to work.

Crossed K-Wires Versus Intramedullary Headless Screw Fixation of Unstable Metacarpal Neck Fractures: A Biomechanical Study

BACKGROUND

Intramedullary headless screw (IMHS) has shown promise as an alternative to other fixation devices for metacarpal neck fractures. The purpose of this study was to assess the biomechanical performance of IMHS versus the commonly-used crossed K-wire technique. We hypothesized that IMHS fixation provides superior stability to K-wires.

METHODS

A metacarpal neck fracture model in 23 human cadaveric metacarpals was created. The specimens were divided into two groups based upon fixation method: Group 1, 3 mm intramedullary headless screw; and Group 2, 0.045 inch crossed K-wires. A cantilever bending model was used to assess load-to-failure (LTF), maximum displacement, energy absorption, and stiffness.

RESULTS

The mean LTF was 70.6 ± 30.1 N for IMHS and 97.5 ± 34.7 N for crossed K-wires. Mean stiffness was 11.3 ± 3.4 N/mm and 17.7 ± 7.8 N/mm for IMHS and crossed K-wires, respectively. The mean maximum displacement was 20.2 ± 4.6 mm for IMHS and 24.1 ± 3.7 mm for crossed K-wires. Moreover, mean energy absorption was 778.3 ± 528.9 Nmm and 1095.9 ± 454.4 Nmm, respectively, for IMHS and crossed K-wires. Crossed K-wires demonstrated significantly higher stiffness and maximum displacement than IMHS (p < 0.05).

CONCLUSIONS

IMHS fixation of unstable metacarpal neck fractures offers less stability compared to crossed K-wires when loaded in bending.

CLINICAL RELEVANCE

Crossed K-wires offer superior stability for the treatment of metacarpal neck fractures. These results reveal that IMHS fixation is less favorable biomechanically and should be cautiously selected with regards to fracture stability.