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.

A Biomechanical Analysis of Oblique Metacarpal Metadiaphyseal Fracture Fixation in a Cadaver Model.

PURPOSE: Although metacarpal fractures are typically managed nonoperatively, when surgical management is indicated, metacarpal fractures are commonly treated with crossed Kirschner wires (K-wires), which may limit early range of motion. Intramedullary implants are increasing in use with the potential advantage of early range of motion; however, stability in oblique metacarpal neck fractures remains a theoretical concern. The purpose of this study was to determine the biomechanical stability of noncompressive intramedullary fixation for oblique metacarpal neck fractures compared with crossed K-wire fixation. METHODS: The index, long, and small metacarpals were harvested from three matched pairs of fresh-frozen cadavers. Oblique fractures at the metadiaphyseal region were created in each metacarpal. Each metacarpal was randomized to noncompressive, threaded intramedullary nail fixation or fixation with two crossed K-wires. Specimens were mounted in a Materials Testing System load frame and axially loaded until failure. Load to failure (LTF), stiffness, and load to 2 mm displacement were calculated from load-displacement curves. Differences in peak LTF, stiffness, and load to 2 mm displacement between noncompressive intramedullary fixation and crossed K-wire fixation were evaluated. RESULTS: The noncompressive intramedullary fixation cohort had a significantly higher LTF (1,190.9 ± 534.7 N vs 297.0 ± 156.0 N) and stiffness (551.3 ± 164.6 N/mm vs 283.0 ± 194.5 N/mm) when compared with the crossed K-wire fixation cohort. Load at 2 mm displacement was greater in the noncompressive intramedullary fixation cohort compared with crossed K-wire fixation (820.5 ± 203.9 vs 514.1 ± 259.6). CONCLUSIONS: For oblique metadiaphyseal metacarpal fractures, noncompressive intramedullary fixation provides a biomechanically superior construct under axial loading in terms of LTF, stiffness, and load to 2 mm of displacement compared with crossed K-wire fixation. CLINICAL RELEVANCE: Noncompressive intramedullary nails may be an alternative to K-wire fixation for the treatment of oblique metadiaphyseal metacarpal fractures.

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.

The Three-Dimensional Relationship of the Axes of the Capitate and Third Metacarpal.

PURPOSE: We quantified the morphology and angulation of the third metacarpal (MC3) relative to the capitate using three-dimensional computed tomography data to inform surgical procedures such as total wrist arthroplasty and wrist arthrodesis. Specifically, we report the three-dimensional location of the intersections of the long axis of MC3 axis with the capitate cortical surface, the sagittal and coronal angles between the MC3 and capitate axes, and the MC3 shaft angle in the sagittal plane. We tested the hypothesis that these metrics did not differ between women and men. METHODS: Three-dimensional bone models of the capitate and MC3 were analyzed in 130 subjects (61M and 69F). Long axes of the MC3 and capitate were computed. The intersection of the metacarpal long axis with the cortical surface of the capitate, the angle between the metacarpal-capitate axes, and metacarpal shaft angle were calculated and compared between men and women. RESULTS: The long axis of the MC3 intersected the capitate at two locations on the outer cortical surface of the capitate. The proximal intersection was located near the midportion of the capitate, whereas the distal intersection was typically located within the capitate-MC3 articulation. The angle between the axes of the capitate and MC3 in the sagittal plane was a mean of 15°, ranging from 5° to 23°. The mean sagittal MC3 shaft angle was 166° and ranged from 158° to 173°.There were only subtle differences in these metrics between the sexes. CONCLUSIONS: The long axis of the MC3 penetrates the dorsal surface of the capitate about its midportion, but there is notable variation in this location as well as in the angular relationships. CLINICAL RELEVANCE: Three-dimensional measurements of the relationships between the third metacarpal and the capitate may serve as an important reference for the placement of intramedullary wires, plates, devices, and prosthetics.

Intramedullary Fixation of Hand Fractures and Arthrodeses.

Intramedullary fixation has long been popular for fracture fixation in the upper extremity from the shoulder through the carpus. Recently, intramedullary fixation in the hand has gained increasing interest, specifically in the metacarpals and phalanges, corresponding with the development of improved cannulated headless screw technology. Along with the advantages of increased operative speed and less surgical dissection, which can promote rapid healing, many benefits exist, supporting their use despite some drawbacks. This article reviews the background and biomechanics of intramedullary fixation with a specific focus on cannulated headless screws, describes the application and techniques of intramedullary screw fixation in the hand, and details the associated outcomes and costs for metacarpal fractures, phalangeal fractures, and interphalangeal joint arthrodesis.

Correction of Congenital Ring-Little Finger Metacarpal Synostosis Through Simultaneous Interpositional Allograft Bone After Split Osteotomy of the Synostosis Site and Distraction Lengthening of the Fifth Metacarpal.

PURPOSE: We attempted a technique for patients with congenital ring-little finger metacarpal synostosis involving simultaneous interpositional allograft bone after split osteotomy of the synostosis site and distraction lengthening of the fifth metacarpal along with correction of the metacarpal joint abduction contracture. The purpose of this study was to describe the surgical technique and its outcomes. METHODS: We reviewed the medical records of children with congenital ring-little finger metacarpal synostosis treated surgically at our institute. Eight hands of six children with an average age of 5.0 (range, 1.7-9.3) years were treated by simultaneous interpositional allograft bone after split osteotomy, distraction lengthening, and tenotomy of abductor digiti minimi. We measured the metacarpal head-to-capitate area ratios from serial radiographs and analyzed them according to age. We also measured the change in the intermetacarpal angle (IMA) and metacarpal length ratio during an average of 8.1 (range, 1.4-16.8) years of follow-up. These changes were compared with changes in seven hands of five children with an average age of 8.1 (range, 1.5-15.6) years treated by the same method, but without a distraction lengthening of the fifth metacarpal and followed up for an of average 12.1 (range, 4.1-19.8) years, as a control group. RESULTS: Abnormal metacarpal head-to-capitate area ratio before surgery was normalized in all patients within the first 2 years after surgery. The IMA change averaged 39.8°, and the metacarpal length ratio changed by 17%. The control group showed an average IMA change of 36.6° and metacarpal length ratio change of 6%. CONCLUSIONS: Simultaneous interpositional allograft bone after split osteotomy of the synostosis site and distraction lengthening of the fifth metacarpal with correction of metacarpal joint abduction contracture can restore the radiographic parameters in congenital ring-little finger metacarpal synostosis. The normalized ossification of the fifth metacarpal head indicates that the surgical procedure is probably safe. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Advances in the Treatment of Hand and Wrist Injuries in the Elite Athlete.

Caring for hand and wrist injuries in the elite athlete brings distinct challenges, with case-by-case decisions regarding surgical intervention and return-to-play. Metacarpal fractures, thumb ulnar collateral ligament tears, and scaphoid fractures are common upper-extremity injuries in the elite athlete that can be detrimental to playing time and future participation. Treatment should therefore endure the demand of accelerated rehabilitation and return-to-activity without compromising long-term outcomes. Fortunately, the literature has supported emerging management options that support goals specific to the athlete. This review examined the advances in surgical and perioperative treatment of metacarpal fractures, thumb ulnar collateral ligament injuries, and scaphoid fractures in the elite athlete.

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.

Management of paediatric fifth metacarpal neck fractures: a systematic review.

BACKGROUND: Fifth metacarpal neck fractures (FMCNFs) are common among paediatric patients. Complications include reduced metacarpophalangeal (MCP) range of motion and grip strength, which impede the hand's functional abilities. Various management options are available, but indications are not standardised. This systematic review aims to assimilate all available evidence on the management of paediatric FMCNFs to determine appropriate treatment pathways. METHODS: PubMed (Medline), EMBASE, Scopus and Google Scholar were used to identify evidence pertaining to the management of these fractures. RESULTS: Ten studies were identified, involving 237 patients with a mean age of 14.4 years (Range 9-17). Ninety percent of patients were male. Sixty-one (26%) patients, with an average fracture angulation of 27° (Range 16°-33°) and no rotational deformities, were managed with immobilisation alone. These patients returned to normal metacarpophalangeal range of motion and grip strength. Fifty-four (23%) patients, with an average fracture angulation of 42.7° (Range 33°-54°), were managed with fracture reduction and immobilisation. This technique did not yield sustained reduction of fractures with significant angulation or rotation after intervention. One hundred twenty-two (51%) patients, with an average fracture angulation of 48.3° (Range 30°-58°) and including cases of malrotation, were managed with fracture reduction and surgical fixation. These patients experienced good functional outcomes. CONCLUSIONS: This review suggests paediatric FMCNFs can be safely managed with immobilisation alone when there is an absence of rotational deformity and an angulation of < 30°. In the case of a higher fracture angulation or rotational deformity, fracture reduction and surgical fixation is an appropriate method of management.

Assocation between trapezium size and failure of total trapeziometacarpal prosthesis. A survival analysis.

AIMS: To assess the survival function of cementless total trapezium metacarpal prostheses (TTMPs) at 20 years, to compare survival functions by trapezium size, and to evaluate the association between the instantaneous risk of TTMP failure and small trapezium size using a multivariate Cox regression model. METHODS: This observational cohort study included 221 consecutive patients with a mean follow-up after TTMP of 137.3 months (maximum of 246 months). Kaplan-Meier and actuarial life-table methods were used to evaluate the survival function of thecohort. Kaplan-Meier survival curves were compared by trapezium size. Multivariate Cox regression analysis was used to determine the effect of potential confounders on the association between small trapezium and the instantaneous risk of TTMP failure. RESULTS: At the end of follow-up, there was a 89.01% chance of the TTMP surviving for 246 months or more. There was an association between TTMP survival time and trapezium size showing a significant trend such that the survival curves weresignificantly higher with larger trapezium size (Mantel-Cox test, p = 0.0001; WilcoxonBreslow test, p = 0.0002; Tarone-Ware test, p = 0.0001).The unadjusted Cox regression model showed a significant association between small trapezium size (smaller than 9 mm) and the instantaneous risk of TTPM failure (HR: 7.37, 95% CI: 2.46-22.07). In the multivariate Cox analysis, "age", "trapezium morphology", and "complications" were confounders in the association between small trapezium size and the hazard ratio of prosthetic failure (HR = 3.76; 95% CI 0.96 to 13.82). CONCLUSION: These results confirm the long-term functional survival of TTMP prostheses and reveal a significant increase in trend of the survival curve with larger trapezium size. Patient age, trapezium morphology, and the presence of post-surgical complications are confounders in the association between small trapezium size and the hazard ratio of TTMP failure.

Indian Hand Anthropometry: Computer Tomography-Based Morphometric Analysis of Metacarpal.

Introduction Metacarpal fractures are common and have various treatment options, but understanding their morphometry is crucial for optimizing fixation techniques and reducing complications. Accurate assessment of metacarpal anatomy is challenging in conventional radiographs but feasible with computed tomography (CT) scans, which offer precise views. This study aimed to provide accurate anatomical data on metacarpals within an Indian population using CT scans and to compare the results with existing literature. The findings have implications for surgical procedures, including plating, pinning, and intramedullary screw fixation. Materials and Methods This retrospective analysis utilized CT scans of 100 hands, including 50 males and 50 females, from two hospitals in India. Inclusion criteria included complete metacarpal visualization with a slice thickness of 0.6 mm, while exclusion criteria involved trauma, deformity, or underlying pathologies. Various parameters of all metacarpals were measured using RadiAnt DICOM Viewer 2021.1, providing accurate anteroposterior and lateral views. Results Male and female cohorts had mean ages of 38.58 ± 12.02 and 43.60 ± 13.61 years, respectively. The study showed good to excellent reliability in measurements. The 2nd metacarpal was consistently the longest, and the general length pattern was 3rd > 4th > 5th > 1st metacarpal in both genders. Men generally had larger metacarpal dimensions than women, except for intramedullary diameter, which showed minimal sex-related differences. Notably, the medullary cavity's narrowest part was at the 4th metacarpal, and the thumb had the widest intramedullary diameter. Conclusion This study provides valuable anatomical reference data for metacarpals in an Indian population, aiding in optimizing surgical techniques for metacarpal fractures. The 2nd metacarpal consistently stood out as the longest, and men generally had larger metacarpal dimensions than women. These insights into anatomical variations can inform clinical decisions and stimulate further research in this field. However, a larger and more diverse sample would enhance the study's representativeness.

Elastic Modulus and Its Relation to Apparent Mineral Density in Juvenile Equine Bones of the Lower Limb.

Density-modulus relationships are necessary to develop finite element models of bones that may be used to evaluate local tissue response to different physical activities. It is unknown if juvenile equine trabecular bone may be described by the same density-modulus as adult equine bone, and how the density-modulus relationship varies with anatomical location and loading direction. To answer these questions, trabecular bone cores from the third metacarpal (MC3) and proximal phalanx (P1) bones of juvenile horses (age <1 yr) were machined in the longitudinal (n = 134) and transverse (n = 90) directions and mechanically tested in compression. Elastic modulus was related to apparent computed tomography density of each sample using power law regressions. We found that density-modulus relationships for juvenile equine trabecular bone were significantly different for each anatomical location (MC3 versus P1) and orientation (longitudinal versus transverse). Use of the incorrect density-modulus relationship resulted in increased root mean squared percent error of the modulus prediction by 8-17%. When our juvenile density-modulus relationship was compared to one of an equivalent location in adult horses, the adult relationship resulted in an approximately 80% increase in error of the modulus prediction. Moving forward, more accurate models of young bone can be developed and used to evaluate potential exercise regimens designed to encourage bone adaptation.

Clinical outcomes of capitellar fractures with posterior comminution treated with Herbert screws combined with metacarpal locking plates.

BACKGROUND: The treatment of Dubberley type B capitellar fractures, which are frequently complicated, is widely debated. This study aimed to investigate the prognostic factors and clinical outcomes of Dubberley type B capitellar fractures treated with Herbert screws combined with posterior buttress plates. METHODS: Seven men and nine women (aged 30-68 years) with Dubberley type B capitellar fractures were operated on with Herbert screws combined with posterior buttress plates. The patients were classified into Dubberley types IB (seven), IIB (four), and IIIB (five). Complications and bone union were observed, and functional outcomes were evaluated by the Mayo Elbow Performance Index (MEPI). RESULTS: All patients were followed up for a mean period of 23.5 months (12-30 months). All fractures healed in 8-14 weeks (mean, 10.5 weeks). No cases of non-union, elbow instability, or avascular necrosis occurred. Degenerative arthritis occurred in 7 (44%) and heterotopic ossification in 11 (69%) patients. The median MEPI score was 92.5 (interquartile range, 85-100) points, with 11 reporting excellent, 3 good, and 2 fair outcomes. The MEPI scores of type IIIB fractures were significantly lower than those of types IB and IIB fractures, while the MEPI scores of type IB and IIB fractures did not differ significantly. CONCLUSIONS: Dubberley type IIIB capitellar fractures with multiple articular fragments have a poorer prognosis than type IB and IIB fractures. However, Herbert screw fixation combined with posterior metacarpal locking plates is feasible, providing satisfactory recovery of elbow joint function.

Outcomes of radial head fractures treated with pre-curved metacarpal plate.

OBJECTIVE: To explore the clinical outcomes of MasonII/III radial head fractures without the neck involvement treated with pre-curved metacarpal plates. METHODS: Ninety cases of Mason typeII/III radial head fractures without the neck involvement were retrospectively collected from the department of orthopaedics of our hospital from September 2015 to May 2021. Group A (n = 44) underwent open reduction and internal fixation with pre-curved metacarpal plate, and Group B (n = 46) were fixed by traditional T-shaped plates. The operation time and the incision length were recorded during the operation. The Mayo Elbow Performance Score (MEPS), Disability of Arm, Shoulder and Hand (DASH) score, visual analogue scale (VAS) for pain, range of motion (ROM) and post-operative complications were evaluated at the last follow-up. RESULTS: All the patients were followed up for at least 12 months. There were no significant difference between two groups regarding operation time (54.2 ± 12.1 v.s 51.3 ± 7.2, mins), MEPS (88.9 ± 4.2 v.s 87.8 ± 4.4), DASH score (7.3 ± 4.6 v.s 9.0 ± 4.0), VAS (1.6 ± 0.8 v.s 1.7 ± 0.7), and ROM. However, the incision length was shorter in Group A (5.6 ± 0.5 v.s 6.6 ± 0.5, cm, P < 0.01). The postoperative complication rate was also lower in Group A (1/44 v.s 8/46, P = 0.02). CONCLUSION: Masson II/III radial head fractures without the neck involvement treated with pre-curved metacarpal plates could achieve satisfactory outcomes comparable to traditional T-shaped plates. Moreover, the invasiveness and postoperative complications are less in patients with pre-curved metacarpal plates. LEVEL OF EVIDENCE: III, retrospective comparison study.

Surgical Outcomes of Percutaneous Pinning and Open Locking Plating in Patients With Intra-articular Fractures of the Base of the Fifth Metacarpal.

PURPOSE: The purpose of the study was to demonstrate the results of surgical treatment, including percutaneous K-wire fixation after closed reduction (CRKF) or locking plate fixation after open reduction (ORPF), in patients with intra-articular fractures of the base of the fifth metacarpal. METHODS: We retrospectively reviewed data of 29 patients who received surgical treatment for closed, intra-articular fractures of the base of the fifth metacarpal and were followed up for at least 1 year after surgery. Sixteen of the 29 patients underwent CRKF, whereas 13 patients underwent ORPF. Attempts were made to address intra-articular step-off with closed reduction in all the patients; however, if inadequate, ORPF was performed. Clinical outcomes were evaluated using Disabilities of the Arm, Shoulder, and Hand scores, visual analog scale pain scores, the total active motion (TAM) of the little finger, and grip strength. Osseous union and posttraumatic arthritis of the fifth carpometacarpal joint were also evaluated. RESULTS: K-wire fixation after closed reduction was performed for 13 simple fractures and 3 comminuted fractures; ORPF was performed for 6 simple fractures and 7 comminuted fractures. All the patients had satisfactory subjective outcomes with over 90% grip strength compared with that on the contralateral side and nearly full TAM. All the patients in both the groups achieved osseous union. There were five cases of grade 1 posttraumatic arthritis after CRKF and seven cases of grade 1 posttraumatic arthritis after ORPF. CONCLUSIONS: Surgical treatment provided satisfactory results in patients with intra-articular fractures of the base of the fifth metacarpal treated with either CRKF or ORPF. Our data showed that the patients who underwent CPKF had good results, and those who underwent ORPF after attempt failure of close reduction also had good results. Our experience suggests that ORPF can be a backup plan when CRKF cannot be accomplished in a satisfactory way. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A Comparative Study of Thumb Metacarpal Morphology and Shape Categorization.

PURPOSE: To describe the shape of a biplanar thumb metacarpal (MC) head and identify how it differs morphologically from previously described flat and round MC heads. METHODS: Lateral radiographs of the thumb were collected retrospectively from our patient database. Patients were included in the study if they had an appropriate lateral radiograph, met the age criteria (range; 18-75 years), and did not have severe metacarpophalangeal (MCP) joint arthritis. Metacarpal heads were categorized as flat or round by dividing the distance measured from the volar to the dorsal edge of the articular surface by the radius of curvature of the articular surface. A ratio of 1.7 or greater indicated a round MC head, whereas a ratio of less than 1.7 indicated a flat MC head. RESULTS: Among the 210 study participants, 110 were female and the average age was 47.3 years. During the measurement and classification process, it was determined by a board-certified hand surgeon that a subset of MCs did not meet the criteria for being categorized as either flat or round because of the inability to appropriately measure the radius of curvature of the MCP joint. Of the participants 113, 79, and 18, were classified as having either round, flat, or biplanar MC head shapes, respectively. CONCLUSIONS: We have identified a third, biplanar MC head shape. The biplanar head shape is more triangular and has two distinct planes on the articular surface that converge into an apex. CLINICAL RELEVANCE: The shape of the MC head has been shown to influence the range of motion of the MCP joint which may have an influence on the types of injuries that occur at the MCP joint. Further studies are required to understand how shape classification of MC heads may be useful and relevant to range of motion and risk of injury.

Metacarpal Lengthening Using a Mini-Ring Ilizarov Device for Thumb Reconstruction.

PURPOSE: To explore the results of using the mini-ring Ilizarov external fixator for thumb metacarpal lengthening and its compatibility with a simultaneous groin flap. METHODS: From May 2016 to June 2019, 17 adult patients with thumb loss were treated with metacarpal lengthening using a mini-ring Ilizarov device. The device was composed of 2 rings, threaded rods, nuts, and K-wires (diameter, 1.5 mm). Of these patients, 6 also underwent simultaneous groin flap transfer. Lengthening was started 3 days after surgery at a rate of 0.66 mm/d. The pedicle of the groin flap was divided 1 month after the surgery. The healing index (days per cm), which denotes the number of days the external fixator is attached to the bone per centimeter of length gained, was used to evaluate the lengthening efficiency. RESULTS: The patients were observed for 21.9 ± 9.0 months. The lengthening continued for 29.1 ± 4.5 days, resulting in an additional length of 1.9 ± 0.3 cm. CONCLUSIONS: The mini-ring Ilizarov external fixator is a simple device for primary metacarpal lengthening. This device can be used with a groin flap for single-stage lengthening of injured thumbs with bone exposure. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Long-Term Outcomes in Female Patients With Carpometacarpal Arthroplasty and Metacarpophalangeal Fusion Compared With the Unoperated Side or Carpometacarpal Arthroplasty.

PURPOSE: Patients with carpometacarpal (CMC) osteoarthritis (OA) often present with metacarpophalangeal (MP) hyperextension and/or thenar atrophy. This study hypothesizes that MP fusion (MPF) performed at the time of CMC arthroplasty (CMCA) for patients who have moderate-to-severe thenar atrophy, MP hyperextension >30°, or MP arthritis will have greater long-term pinch strength and improvements in the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score from preoperative values when compared with the unoperated side or those who had CMCA only. METHODS: This study involved a retrospective review of long-term results from patients who underwent either CMCA or CMCA/MPF. The QuickDASH score, the pain visual analog scale (VAS), and an average of three pinch readings from each thumb were measured on the Baseline pinch gauge and recorded with a correction for hand dominance in right-handed patients. RESULTS: Fifty-three female patients with 70 operated thumbs were included in the study. The mean age was 67.2 years. There were 29 CMCAs and 41CMCA/MPFs. The mean follow-up was 6.3 years (range 2-16.9 years). At the latest follow-up, the mean CMCA/MPF pinch strength (11.3 lbs) was significantly stronger than that of CMCA (8.0 lbs) and carpometacarpal osteoarthritis thumbs (8.9 lbs). There was no significant difference in pinch strength between patients who underwent a CMCA and CMCOA thumbs (8.0 lbs vs 8.9 lbs, respectively). Preoperative QuickDASH demonstrated worse function in the CMCA/MPF group (55.8 vs 36.5). At the latest follow-up, QuickDASH and VAS revealed similar values in both the CMCA/MPF (10.5 and 0.66) and CMCA (18.5 and 0.52) groups. CONCLUSION: Long-term results demonstrate stronger pinch and greater improvement in QuickDASH scores in patients who underwent CMCA/MPF compared with those who underwent a CMCA or untreated carpometacarpal osteoarthritis thumbs. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Factors Associated With Implant Removal Following Plate-and-Screw Fixation of Isolated Metacarpal Fractures.

PURPOSE: The incidence of and associated risk factors for implant removal following the plate-and-screw fixation of metacarpal shaft fractures have not been well described. The primary objective of our study was to identify implant-related radiographic parameters associated with implant removal in patients treated with the plate-and-screw fixation of isolated, displaced metacarpal fractures at 2 years of follow-up. The secondary objective of our study was to identify patient-related factors associated with implant removal. METHODS: A retrospective study of all patients who underwent open treatment of a metacarpal fracture with a plate-and-screw construct from January 1, 2000, to April 30, 2019, at 2 level-1 trauma centers was conducted. After the application of exclusion criteria, we identified 138 patients with a single isolated metacarpal fracture of a nonthumb digit treated with open reduction and internal fixation using a plate-and-screw construct. Our study endpoint was the removal of the plate-and-screw construct or a minimum of 2 years of follow-up without the removal of the hardware. Twenty-three patients achieved our study endpoint as determined using their electronic medical records, and 58 additional patients were reached via telephone to confirm their implant removal status. A bivariate analysis was used to screen for factors associated with implant removal, and variables significant in the bivariate screen were included in a multivariable stepwise logistic regression model. RESULTS: Twenty-three out of 81 patients (28%) in our final cohort underwent implant removal by the final follow-up visit. In the logistic regression analysis, the distance between the plate and metacarpophalangeal joint, the distance between the plate and carpometacarpal joint, and active smoking were independently associated with implant removal. CONCLUSIONS: The proximity of metacarpal plates to adjacent joints is associated with subsequent implant removal. Patients may be counseled about the higher risk of implant removal when periarticular metacarpal plating is performed. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognosis IV.

Complications Following Intramedullary Screw Fixation for Metacarpal Fractures: A Systematic Review.

PURPOSE: There has been a recent increase in the use of intramedullary screws (IMS) for the surgical treatment of metacarpal fractures. While IMS fixation has been shown to produce excellent functional outcomes, postoperative complications have yet to be fully explored in a comprehensive way. This systematic review quantified the incidence, treatment, and results of complications following IMS fixation for metacarpal fractures. METHODS: A systematic review was performed using PubMed, Cochrane Central, EBSCO, and EMBASE databases. All clinical studies that documented IMS complications following metacarpal fracture fixation were included. Descriptive statistics were analyzed for all available data. RESULTS: Twenty-six studies were included: 2 randomized trials, 4 cohort studies, 19 case series, and 1 case report. Among the 1,014 fractures studied, 47 complications were reported across all studies (4.6%). Stiffness was the most common, followed by extension lag, loss of reduction, shortening, and complex regional pain syndrome. Other complications included screw fracture, bending, and migration; early-onset arthrosis; infection; tendon adhesion; hypertrophic scar; hematoma; and nickel allergy. Eighteen of the 47 (38%) patients with complications underwent revision surgery. CONCLUSIONS: Complications following IMS fixation of metacarpal fractures are relatively uncommon. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.