Relationship between trapeziometacarpal joint morphological parameters and joint contact pressure: a possible factor of osteoarthritis development.

The trapeziometacarpal (TMC) joint is the one of the hand joints that is most affected by osteoarthritis (OA). The objective of this study was to determine if specific morphological parameters could be related to the amount of pressure endured by the joint which is one of the factors contributing to the development of this pathology. We developed 15 individualized 3D computer aided design (CAD) models of the TMC joint, each generated from the CT scan of a different participant. For each participant, we measured several crucial morphological parameters: the width and length of the trapezium bone and dorso-volar and ulno-radial curvature, of the trapezium and the metacarpal bone. Each CAD model was converted into a finite element model, of both bones and the cartilage located in between. The joint forces applied during pinch grip and power grip tasks were then applied in order to estimate the contact pressures on joint cartilage for each model. Correlations between joint contact pressures and morphology of the trapezium and the metacarpal bone were then analysed. Important variations of TMC joint pressures were observed. For both pinch and power grip tasks, the strongest correlation with joint contact pressure was with the dorso-volar curvature of the trapezium bone. Our findings indicate that dorso-volar curvature of the trapezium bone has a significant impact on mechanical loadings on the TMC joint. This contributes to understanding the prevalence of OA in certain patients.

Pin vs plate fixation for metacarpal fractures: a meta-analysis.

BACKGROUND: The differences in the clinical and functional outcomes of closed reduction and percutaneous pin fixation and open reduction with internal fixation (ORIF) using plate and screws have been systematically synthesized by one meta-analysis. With newer studies being published, an effort to update the earlier meta-analysis is necessary. METHODS: Comprehensive searches were done systematically through PubMed, Scopus, CENTRAL (Cochrane Central Register of Controlled Trials), and Google scholar databases. Randomized controlled trials, quasi-experimental studies, prospective comparative non-randomized studies, and even studies reporting findings from retrospective chart review were eligible to be included. Statistical analysis was done using STATA version 13.0. GRADE assessment was done to assess the quality of pooled evidence. RESULTS: A total of 9 studies were included. The pooled estimates did not suggest any significant differences in the disabilities of the arm, shoulder, and hand (DASH) score [WMD - 0.77; 95% CI, - 3.55, 2.00; I2 = 75.5%], range of movement (ROM) of the metacarpophalangeal joint (o) [WMD 4.44; 95% CI, - 4.19, 13.07; I2 = 86.0%], and grip strength [WMD - 4.63; 95% CI, - 14.52, 5.26; I2 = 86.9%] among the two intervention modalities. No difference was seen in the risk of complications between the two interventions (RR 0.93; 95% CI, 0.57, 1.53; I2 = 31.2%). For all the outcomes, the quality of pooled evidence was judged as low to very low. CONCLUSION: No significant long-term differences were noted in the functional outcomes suggesting that both these techniques are comparable. The choice of modality should be made based on the skills and preference of the surgeon and availability of resources.

Effects of in vivo fatigue-induced subchondral bone microdamage on the mechanical response of cartilage-bone under a single impact compression.

Subchondral bone (SCB) microdamage is prevalent in the joints of human athletes and animals subjected to high rate and magnitude cyclic loading of the articular surface. Quantifying the effect of such focal in vivo fatigue-induced microdamage on the mechanical response of the tissue is critical for the understanding of joint surface injury and the development of osteoarthritis. Thus, we aimed to quantify the mechanical properties of cartilage-bone from equine third metacarpal (MC3) condyles, which is a common area of accumulated microdamage due to repetitive impact loading. We chose a non-destructive technique, i.e. high-resolution microcomputed tomography (µCT) imaging, to identify various degrees of in vivo microdamage in SCB prior to mechanical testing; because µCT imaging can only identify a proportion of accumulated microdamage, we aimed to identify racing and training history variables that provide additional information on the prior loading history of the samples. We then performed unconfined high-rate compression of approximately 2% strain at 45%/s strain rate to simulate a cycle of gallop and used real-time strain measurements using digital image correlation (DIC) techniques to find the stiffness and shock absorbing ability (relative energy loss) of the cartilage-bone unit, and those associated with cartilage and SCB. Results indicated that stiffness of cartilage-bone and those associated with the SCB decreased with increasing grade of damage. Whole specimen stiffness also increased, and relative energy loss decreased with higher TMD, whereas bone volume fraction of the SCB was only associated negatively with the stiffness of the bone. Overall, the degree of subchondral bone damage observed with µCT was the main predictor of stiffness and relative energy loss of the articular surface of the third metacarpal bone of Thoroughbred racehorses under impact loading.

Tendon versus Pyrocarbon Interpositional Arthroplasty in the Treatment of Trapeziometacarpal Osteoarthritis.

BACKGROUND: Trapeziometacarpal (TMC) arthritis is treated with surgery when nonsurgical treatment fails. The best surgical option for improving pain relief, functional outcomes, and postoperative complications remains controversial. The purpose of this study was to compare clinical and radiological outcomes and complications between trapezium excision with ligament reconstruction and tendon interposition (LRTI) and pyrolytic carbon interpositional arthroplasty. METHODS: From March 2009 to August 2014, 37 patients (39 wrists) with Eaton-Littler stage II or III TMC arthritis underwent complete trapezium excision with LRTI (Group L, n=19) or pyrolytic interpositional arthroplasty (Group P, n=20). Visual analog scale (VAS) pain scores; grip and pinch strength; Kapandji scores to quantify thumb opposition; and Disabilities of Arm, Shoulder, and Hand (DASH) scores were used to compare clinical outcomes between the two groups. Radiographic changes (metacarpal shortening, subluxation, and radiolucency) were evaluated on the radiographs of thumb basal joints. RESULTS: There were no differences in patient demographics, Eaton-Littler stage, preoperative outcome measures, or the duration of follow-up between the two groups. At the last follow-up, VAS pain scores, pinch and grip strengths, Kapandji scores, and DASH scores were significantly improved in both groups compared with preoperative scores. All follow-up measurements were similar between the two groups except pinch strength, which was 1.8 kg higher in Group P (p<0.001). Proximal metacarpal migration did not differ significantly between the groups. Periprosthetic lucency more than 1 mm was observed in 7 of 20 (35%) thumbs. Complication rates were similar between the two groups. CONCLUSIONS: All subjective and objective outcomes were similar following LRTI and pyrolytic interpositional arthroplasty in patients with TMC arthritis, except pinch strength, which was more improved following pyrolytic interpositional arthroplasty. Longer follow-up is required to test adverse effects of high rates of periprosthetic lucency and prosthetic subluxation on clinical outcomes after PyroDisk interpositional arthroplasty.

Open reduction and internal fixation versus closed reduction and percutaneous fixation in the treatment of Bennett fractures: A systematic review.

PURPOSE: Open reduction and internal fixation (ORIF) of Bennett fractures is increasingly preferred over closed reduction and percutaneous fixation (CRIF) in an attempt to prevent the development of post-traumatic arthrosis. The aim of this systematic review was to determine whether the preference for ORIF is justified based on the available literature regarding functional outcome and complications after surgery. METHODS: A systematic review was performed in Medline, Embase, Cochrane CENTRAL, Web of science, and Google scholar. Duplicates were removed and title and abstract were screened after which full text articles were analysed. The reference lists of selected articles were screened for additional relevant studies. Study characteristics were recorded and methodological qualities were assessed after which data was extracted from the included articles. The Eaton-Littler score for post-traumatic arthrosis (primary outcome) on follow-up X-rays was used as primary outcome. Secondary outcomes were Grip strength, Pinch strength, persistent pain, fixation failure, functional impairment, infection and surgery time. RESULTS: Ten studies were included; three retrospective comparative studies and seven retrospective case series. Of the 215 patients in these studies, 138 had been treated using an open technique and 77 by a closed percutaneous technique. The pooled rate of post-traumatic arthrosis was 57.5% (26.6-85.5) in the ORIF group versus 26.1% (3.9-59.0) in the CRIF group. Mean surgical operation time was 71.9 min for ORIF and 30.2 min for percutaneous patients. Fixation failure was significantly more often seen in the ORIF patients, 8.2% (0.7-22.8) vs. 2.9% (0.8-9.1), Risk Ratio 1.132 (0.01-176.745); p = 0.048. Infection was only seen in 5 CRIF patients. Persistent pain was seen in 32.9% (0.6-83.1) in ORIF patients versus 22.3% (8.1-41.1) in the CRIF patients. The pooled means Grip strength was 48.3 kg (95% CI; 39.7-56.9) versus 43.4 kg (95% CI; 22.9-63.8) for ORIF and CRPF, respectively. Functional impairment was similar between the two groups, 1.4% (0.1-4.4) vs 1.8% (0.1-5.7) respectively. CONCLUSION: The analysed data do not confirm ORIF to prevent post-traumatic arthrosis, secondly more fixation failure and pain was seen in the ORIF group. The pooled data show percutaneous fixation to be preferable over ORIF in the surgical treatment of Bennett fractures.

Influence of the trapeziometacarpal joint fusion on thumb muscles and thumb-tip movement: A cadaveric study.

BACKGROUND: Trapeziometacarpal (TMC) arthrodesis provides stability and strength of the thumb, whereas fixation of the TMC joint restricts motion of the thumb, which may consequently impair the activity of daily living. The objective of our study was to investigate how length and area of the thumb-tip trajectory were reduced after the TMC joint fusion. METHODS: Six fresh, frozen cadavers were used for this study. Tension was applied to the distal tendons of 4 extrinsic thumb muscles (extensor pollicis longus, flexor pollicis longus, abductor pollicis longus, and extensor pollicis brevis) by servomotor, whereas tension was applied to 4 intrinsic muscles (abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, and adductor pollicis) using static weights. The thumb-tip trajectory was examined using a motion capture system without tension and with 5 different weights to induce intrinsic muscle tension before and after the TMC joint fusion. FINDINGS: When tension was applied to the intrinsic muscles, the length of the thumb-tip trajectory decreased in all conditions compared with that before the TMC joint fusion, whereas the trajectory decreased only when the abductor pollicis longus was pulled. The overall thumb-tip trajectory area was reduced to approximately 30% compared with that before the TMC joint fusion. INTERPRETATION: Thumb-tip trajectory was restricted by the TMC joint fusion to approximately 30%. However, the reduced area was found tolerable for performing daily activities. Thus, arthrodesis can be the first-line treatment in patients who wish to engage in activities of daily living without difficulties.

[Biomechanical comparison of six different fixation techniques for treatment of metacarpal neck fractures]. / Biomechanischer Vergleich sechs verschiedener Fixationstechniken zur Versorgung von Halsfrakturen der Metakarpale.

PURPOSE: The purpose of this study was to evaluate the primary stability of commonly used fixation techniques for metacarpal neck fractures and to compare it with that of an innovative osteosynthesis device: IlluminOss™, the photodynamic bone stabilization system™. MATERIAL AND METHODS: Metacarpal neck fractures were created on the second to fifth metacarpal bones of 24 freshly frozen human cadavers using a band saw. Specimens were randomly assigned to one of six groups and treated with (1) K-wire fixation, (2) dorsal plating, (3) external fixation, (4) cross-threaded K­wire fixation, (5) IlluminOss™ and (6) locked IlluminOss™. In each group 16 specimens each underwent either monocyclic or polycyclic loading protocols. RESULTS: During monocyclic loading none of the specimens failed prior to a maximum deformation of 3 mm. With intramedullary K­wire fixation the mean loads were significantly lower than those of the other techniques. Mean loads causing 2 mm deformation with external fixation were significantly lower than those with dorsal plate osteosynthesis. The mean linear stiffness of the K­wire osteosynthesis was significantly lower than for the other fixation techniques and all methods of external fixation were significantly lower than dorsal plates. There were no significant differences with respect to the linear stiffness between the groups with dorsal plates, fragment fixation system (FFS), IlluminOss™ and locked IlluminOss™. During polycyclic testing the loss of resistance in dorsal plate osteosynthesis was significantly lower than with K­wire and IlluminOss™ fixation. No significant differences in loss of resistance could be shown between dorsal plate osteosynthesis, external fixation, FFS and locked IlluminOss™. CONCLUSION: In summary, IlluminOss™ can be used as an intramedullary stabilization system for treatment of metacarpal neck fractures. In combination with locking screws the biomechanical characteristics of IlluminOss™ are comparable to the other fixation techniques.

The diagnostic clinical value of thumb metacarpal grind, pressure-shear, flexion, and extension tests for carpometacarpal osteoarthritis.

STUDY DESIGN: Clinical measurement. INTRODUCTION: Common provocative maneuvers to differentiate thumb carpometacarpal (CMC) osteoarthritis from other sources of pain are the grind, metacarpal (MC) flexion, and MC extension tests. A maneuver known as the pressure-shear test is described here. PURPOSE OF THE STUDY: To compare the diagnostic value of the grind, metacarpal flexion, metacarpal extension, and pressure-shear tests for CMC osteoarthritis of the thumb. METHODS: The diagnostic accuracy of each test was compared in 127 thumbs from 104 patients. Sensitivity, specificity, and predictive values of each test were calculated. In a secondary analysis, polychoric correlation coefficients were used to assess the correlation of each test with severity defined by Eaton-Littler stage. RESULTS: The overall diagnostic accuracy of the thumb MC grind, pressure-shear, flexion, and extension tests were 70%, 98%, 47%, and 55%, respectively. The sensitivities were 64%, 99%, 36%, and 46%, respectively, and specificities were 100%, 95%, 100%, and 100%, respectively. For the diagnosis of Thumb CMC arthritis, the MC pressure-shear test was superior overall in terms of overall diagnostic accuracy and sensitivity, while having comparable specificity to the other maneuvers. CONCLUSION: The pressure-shear test was found to be superior to the commonly used grind maneuver and the provocative maneuvers of MC flexion and extension tests to confirm diagnosis of CMC osteoarthritis.

Outcomes of Surgical Management for Thumb Basilar Arthritis in Patients 55 Years of Age and Younger.

Background: Trapeziectomy with ligament reconstruction tendon interposition (LRTI) or suspensionplasty is an effective treatment in older patients with end-stage thumb basilar arthritis. However, the survivability of this procedure is unknown in younger patients who may impart more stress on their thumbs. Methods: A retrospective review was performed on all patients who underwent trapeziectomy and LRTI or suspensionplasty at 55 years of age or younger from 1992 to 2008. Objective clinical outcome measures included preoperative to postoperative changes in thumb range of motion, grip and pinch strength, a study-specific thumb function score, and the Buck-Gramcko subjective outcome score. Progressive metacarpal subsidence was evaluated on radiographs. Survivorship free from revision surgery was calculated with a Kaplan-Meier analysis. Results: A total of 57 wrists underwent trapeziectomy and LRTI (n = 18) or suspensionplasty (n = 39). The mean patient age at the time of surgery was 49.6 years (range: 38-55 years). Mean clinical and radiographic follow-up were 10.2 and 6.4 years, respectively. Overall, there were significant improvements in pain and grip strength despite progressive and metacarpal subsidence. Survivorship was 100% and 86% free from revision surgery at 10 and 15 years, respectively (n = 2 failures). Conclusions: Trapeziectomy and LRTI or suspensionplasty in patients less than or equal to 55 years of age can result in considerable improvements in pain and grip strength with a 10-year survivorship free from revision.

Evaluation of low bone mass and prediction of fracture risk using metacarpal radiogrammetry method: a comparative study with DXA and X-ray phantom.

OBJECTIVES: (i) To predict the future risk of osteoporotic fracture in women using a simple forearm radiograph. (ii) To assess osteoporosis in southern Indian women by using radiogrammetric technique in comparison with dual-energy X-ray absorptiometry (DXA) and X-ray phantom study. METHODS: The bone mineral density (BMD) of the right proximal femur by DXA and the X-ray measurements were acquired from the right forearm. The combined cortical thickness at the second to fourth metacarpal region (M-CCT), radius (R-CCT) and ulna (U-CCT) were derived in all the studied population. The aluminium phantom study was conducted by varying the X-ray source to film distance at 100 cm and 150 cm, respectively. The feed forward back propagation neural network was used for classification of low bone mass group and normal. RESULTS: The combined cortical thickness of M-CCT, R-CCT and U-CCT of the total studied population was strongly correlated with DXA femur Th.BMD measurements (r = 0.77, r = 0.61 and r = 0.59 [P < 0.01]). The predicted future osteoporotic fracture risk for the low bone mass group, post-menopausal women and old-aged women population was found to be 92%, 62.8%, and 64.7%, respectively. The accuracy of neural network classifier for training set, testing set was found to be 97.5% and 87.5% in the studied population. CONCLUSION: The results suggested that M-CCT and M-CCT (%) at the second metacarpal region are useful in predicting the future risk of osteoporotic fracture in women. The aluminium phantom study with an X-ray tube to film distance of 100 cm mimics an exact condition of forearm radiogrammetry.

The influence of bone loss on the three adult age markers of the innominate.

To evaluate the influence of bone loss on the three adult age markers of the innominate, 30 males and 30 females aged between 16 and 80 years coming from the British Coventry collection were analyzed. The pubic symphysis, auricular surface, and acetabulum age variables were evaluated following the descriptions of Schmitt, Buckberry-Chamberlain, and Rissech, respectively. The second metacarpal cortical index was used to evaluate bone loss. Possible sexual differences in metrical variables were explored by a Student t-test taking into account the entire sample. The possible relationships between the cortical index and the three age methods' stages were assessed by the Kruskall-Wallis test and Spearman's correlation coefficient. There were no sexual differences in the cortical index. In general, we observed no significant differences between the cortical index in the different stages of the pubic symphysis, auricular surface, or acetabulum variables in men and women. Most correlation coefficients are negatives, and their absolute values are between 0.001 and 0.44, indicating an extremely low influence of bone loss on the analyzed variables. Our findings suggest little influence of bone loss in the three ageing methods. However, further research on this topic is necessary. This is the first study to analyze the influence of bone loss in the ageing changes undergone by the variables of the three adult age indicators of the innominate taking into account both sexes.

Changes in Local Bone Density in Early Thumb Carpometacarpal Joint Osteoarthritis.

PURPOSE: Thumb carpometacarpal (CMC) osteoarthritis (OA) represents a major source of functional morbidity. The effects of early CMC OA on loading and use patterns potentially lead to changes in local bone density and microarchitecture. Hounsfield units (HU), a quantitative attenuation coefficient obtained from computed tomography (CT) scans, have been shown to be a reliable marker of bone density. We hypothesized that early CMC OA is associated with lower local bone density about the CMC joint as assessed by HU. METHODS: We examined HU units from CT scans in 23 asymptomatic subjects and 91 patients with early CMC OA. The HU measurements were obtained within cancellous portions of the trapezium, capitate, first and third metacarpal bases, and distal radius. Linear regression models, with age and sex included as covariates, were used to assess the relationship between CMC OA and HU values at each anatomical site. RESULTS: Early OA patients had significantly lower HU than asymptomatic subjects within the trapezium (mean, 377 HU vs 436 HU) and first metacarpal bases (265 HU vs 324 HU). No significant group differences were noted at the capitate, third metacarpal, or distal radius. Male sex and younger age were associated with significantly higher HU at all the anatomical sites, except the first metacarpal base, where age had no significant effect. CONCLUSIONS: Subjects presenting with early CMC OA had significantly lower bone density as assessed with HU at the thumb CMC joint (trapezium and first metacarpal base). Early thumb CMC OA and discomfort may lead to diminished loading across the basal joint, producing focal disuse osteopenia. These findings in symptomatic early arthritis suggest a relationship between symptoms, functional use of the CMC joint, and local bone density. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Three-screw versus two-screw fixation of distal fragment in fifth metacarpal neck fractures stabilized with locking plate.

Fifth metacarpal neck fracture commonly requires open reduction and internal fixation. Locking plate was widely adopted in the treatment of fifth metacarpal neck fracture as first-line choice for fixation. Patients with fifth metacarpal neck fracture receiving locking plate fixation were included for analysis. Features of internal fixation including number of distal and proximal locking screws, diameter of the screws and usage of lag screws were recorded. Clinical and radiographic outcomes included final volar angulation, grip strength, Michigan Hand Outcomes Questionnaire (MHQ) and range of motion (ROM) of fifth metacarpophalangeal joint. Three-screw fixation was less frequently presented in the group with increased volar angulation (≥30 degrees). Consistently, three-screw fixation of distal fragment could improve the prognosis compared with two-screw fixation (MHQ 95.4 ± 5.1 versus 80.4 ± 12.3, ROM 83.5 ± 7.2 versus 69.6 ± 7.7). In conclusion, the metacarpal head should be fixed by three locking screws instead of two locking screws.

A biomechanical analysis of plate fixation using unicortical and bicortical screws in transverse metacarpal fracture models subjected to 4-point bending and dynamical bending test.

In the published literature there are controversial data to the biomechanical stability of monocortical comparing to the bicortical fixation of metacarpal fractures. The aim of this study was to compare the biomechanical stability of monocortical and bicortical locking osteosynthesis in quasi-static and dynamic 4-point bending tests of composite third metacarpal bone (4th Gen third metacarpal, Sawbones, Malmö, Sweden) fixed with 7-hole locking plate (XXS System, Biotech-Ortho, Wright, Memphis, TN). The tests to determine quasi-static yield and bending strength as well as fatigue strength were conducted in 4 groups of 10 samples after creating standardized mid-shaft transverse osteotomies using a diamont belt grinder (0.3 mm saw blade). The force applied was the dorsal apex loading, similar to the forces applied to metacarpals during normal finger flexion and extension.In the quasi-static testing, no plate breakage was observed in each group. All metacarpals broke at their thinnest part. The average bending strength of the bicortical samples (10.54 ±â€Š0.998 Nm) was significantly higher comparing to the monocortical samples (8.57 ±â€Š0.894 Nm) (P < .001).In the dynamic loading test, all constructs (8 monocortical samples and 7 bicortical) that failed broke at the osteotomy site and the average fatigue strength did not differ in both groups.Consequently, a unicortical plating method may provide adequate strength and stability to metacarpal fractures based on the results of the cyclical loading representative of in vivo loading.

Biomechanical causes of trapeziometacarpal arthroplasty failure.

Trapeziometacarpal joint prosthesis revision has been widely reported, mainly due to loosening of the trapezium cup. Our hypothesis is that current prostheses do not sufficiently respect the kinematics of this joint. CT scan acquisitions enabled us to determine the position of the first metacarpal relative to the trapezium in three different characteristic postures, in subjects in different stages of arthrosis. A CAD model of a current prosthesis was inserted into the numerical 3D model of the joint under the different postures. In the numerical model, we observe penetration of the cup by the head of the prosthesis. This virtual penetration could, in vivo, amount to overstressing the prosthetic elements, which would lead to loosening of the cup or of the metacarpal stem and luxation of the prosthesis.

Locking Plate Alone versus in Combination with Two Crossed Kirschner Wires for Fifth Metacarpal Neck Fracture.

Fracture of fifth metacarpal neck commonly requires open reduction and internal fixation. However, the current methods of internal fixation in fifth metacarpal neck fractures remain unsatisfactory. Patients with fractures of fifth metacarpal neck received open reduction and internal fixation with either locking plate in combination with two crossed Kirschner wires (K-wires) or locking plate alone were evaluated for the clinical outcomes. Clinical outcomes included grip strength, Michigan hand outcomes questionnaire (MHQ), final angulation and range of motion (ROM) one year after treatment. The averages of MHQ scores, final angulation and ROM of fifth metacarpophalangeal joint of plate with K-wire group were more superior to those of plate group (MHQ 96.7 versus 86.6, final angulation 11.8 versus 23.6, ROM 83.3 versus 72.2). The grip strength had no significant difference between two groups. Locking plate in combination with two crossed K-wires is a more optimal method of fixation compared with locking plate alone.

Comparison of 2-Dimensional and 3-Dimensional Metacarpal Fracture Plating Constructs Under Cyclic Loading.

PURPOSE: Metacarpal fractures are commonly treated by a variety of means including casting or open reduction internal fixation when unacceptable alignment is present following attempted closed reduction. Dorsal plating with either single-row 2-dimensional or double-row 3-dimensional plates has been proposed. This study's purpose was to determine if there are any differences in fixation construct stability under cyclic loading and subsequent load to failure between the lower profile 3-dimensional and the larger 2-dimensional plates in a metacarpal fracture gap sawbone model. METHODS: Thirty metacarpal cortico-cancellous synthetic bones were cut with a 1.75-mm gap between the 2 fragments simulating mid-diaphyseal fracture comminution. Half of the metacarpals were plated with 2.0-mm locking 2-dimensional plates and half with 1.5-mm locking 3-dimensional plates. The plated metacarpals were mounted into a materials testing apparatus and cyclically loaded under cantilever bending for 2,000 cycles at 70 N, then 2,000 cycles at 120 N, and finally monotonically loaded to failure. Throughout testing, fracture gap sizes were measured, failure modes were recorded, and construct strength and stiffness values were calculated. RESULTS: All 3-dimensional constructs survived both cyclic loading conditions. Ten (67%) 2-dimensional constructs survived both loading conditions, whereas 5 (33%) failed the 120-N loading at 1377 ± 363 cycles. When loaded to failure, the 3-dimensional constructs failed at 265 N ± 21 N, whereas the 2-dimensional constructs surviving cyclic loading failed at 190 N ± 17 N. CONCLUSIONS: The shorter, thinner 3-dimensional metacarpal plates demonstrated increased resistance to failure in a cyclic loading model and increased load to failure compared with the relatively longer, thicker 2-dimensional metacarpal plates. CLINICAL RELEVANCE: The lower-profile 3-dimensional metacarpal plate fixation demonstrated greater stability for early postoperative resistance than the thicker 2-dimensional fixation, whereas the smaller size and lower profile of the 3-dimensional plates potentially reduces soft tissue stripping, implant prominence, and risk of extensor tendon irritation.

Digital Lengthening to Treat Finger Deficiency: An Experience of 201 Digits in 104 Patients.

Objectives. We evaluated the results of digital lengthening by distraction and second-stage bone graft. Methods. We treated finger deficiency of 201 digits in 104 patients (68 males, 36 females) by digital distraction and second-stage bone graft. The distraction was performed with a rate of 1 mm/day (for the first ten days) and 0.5 mm/day followed by using a self-designed bilateral tubal-helical external fixator. The mean follow-up period was 42 months (range 6 to 60 months). Results. The mean lengthening was 29.2 mm (range 25 to 40 mm) and 18.7 mm (range 12 to 32 mm) for metacarpal bones and phalanges, respectively. The mean elongation rate was 174.4% (range 145% to 202%) and 184.8% (range 115% to 283%) for metacarpal bones and phalanges, respectively. The static two-point discriminations and SpO2 showed no significant differences before and after distraction. Four complications were observed (two skin ruptures and two phalangeal splitting). No pin tract infection or tendon rupture showed. Digital lengthening improved functions of the hand. Conclusion. Digital distraction and second-stage bone graft is an effective method to compensate disabilities caused by lack of finger length. It could be an alternative plan for patients with thumb deficiency instead of toe-to-thumb transplant and patients with finger deficiency instead of ray resection.

Bennett Fractures A Review of Management.

A Bennett fracture is a common injury that involves an intra-articular fracture at the base of the first metacarpal. This fracture typically results in a dorsally and radially displaced metacarpal shaft relative to the well-anchored volar ulnar fragment. Most Bennett fractures are treated with operative fixation, including closed reduction and percutaneous fixation, open reduction and internal fixation, or arthroscopically assisted fixation. However, the optimal surgical approach is controversial. There is a paucity of literature comparing the outcomes of the various treatments, leaving the surgeon without a clear treatment algorithm. Moreover, there is no consensus on acceptable reduction parameters, including articular gap or step-off, with some series stating that up to 2 mm of displacement is acceptable.

Interposition Arthroplasty Versus Hematoma and Distraction for the Treatment of Osteoarthritis of the Trapeziometacarpal Joint.

BACKGROUND: Various surgical techniques were reported with excellent result for the treatment of trapeziometacarpal joint arthritis. However, the best treatment option was not defined yet. METHODS: This randomized prospective study compared the result of two surgical techniques: tendon interposition arthroplasty (64 patients) and K. wire distraction (56 patients) after trapeziectomy for stage 3 or 4 osteoarthritis of the trapeziometacarpal joint. RESULTS: After a mean follow-up period of 6.8 (range, 3-10) years it was possible to observe a higher rate of pain relief following trapeziectomy with K. wire suspension, but no significant differences in strength, range of motion and DASH score between the two groups. On lateral unloaded radiographs the height of the space between the base of the thumb metacarpal and the scaphoid showed a mean value of 6.5 mm for both groups; the average distance between the metacarpal base and the trapezium was not statistically significant in the two groups. Complications were observed only in patients treated with trapeziectomy and interposition arthroplasty and were represented by tendinitis of the FCR in 15% of cases. CONCLUSIONS: We demonstrate that the trapezium excision and bone space distraction technique requires a smaller incision, a shorter surgical time, an easier surgical technique, and a less painful recovery, maintaining overlapping levels of functional restore.