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.

Phenotype-considered kinematically aligned total knee arthroplasty for windswept-deformity-associated osteoarthritis: surgical strategy and clinical outcomes.

BACKGROUND: Windswept deformity (WSD) in relation to advanced osteoarthritis (OA) presents a significant surgical challenge in total knee arthroplasty (TKA). The primary goal of this study is to investigate the Prevalance of WSD associated osteoarthritis who have undergone total knee arthroplasty. The secondary goal is to explore the causes of WSD and its association with spinal deformity or leg length discrepancy in these patients. Finally, we evaluate the surgical outcomes of phenotype-considered kinematically aligned TKA (KA-TKA) in treating patients with WSD. METHODS: A review was conducted on data from 40 knees of 33 WSD patients who underwent phenotype-considered KA-TKA from August 2016 to December 2020. Patient demographics, associated diseases, preoperative and postoperative knee alignment angles, range of motion (ROM), Oxford Knee Score (OKS), and Knee Society Score (KSS) were collected and analyzed. Subgroup analysis for comparing the results between valgus and varus knees were also performed. RESULTS: Within the studied cohort of WSD patients, a substantial 64% displayed concomitant coronal spinal imbalance and 21% evidenced leg length discrepancy. Postoperative improvements were notable in knee alignments, ROM, OKS, and KSS following the application of the phenotype-considered KA-TKA approach. There were significant differences in the knee alignment angles, including mHKA, LDFA, and MPTA, between the valgus and varus side of knees (P = 0.018). However, no statistically significant difference were observed in the functional scores, comprising ROM, OKS, and KSS, between valgus and varus knees. CONCLUSIONS: A high percentage of patients with WSD exhibited coronal spinal imbalance and leg length discrepancy. Phenotype-considered KA-TKA effectively provided alignment targets for the treatment of both varus and valgus knees in patients with WSD, achieving excellent short-term outcomes and acceptable knee alignment.

Effect of intraoperative hand-grip position on surgical outcome of thumb carpometacarpal arthrodesis.

BACKGROUND: A variety of surgical techniques had been developed over the past few decades for treating thumb carpometacarpal joint (CMCJ) osteoarthritis (OA). However, there are currently no accepted consensus on the ideal treatment for thumb CMCJ OA. Arthrodesis was one of the widely popular treatment methods; however, studies have showed that non-union rates were as high as 50%, with higher complications such as osteoarthritis of neighbouring joints and higher revision surgeries required as compared to other surgical methods. Patients with arthrodesis were also reported to have decreased thumb range of motion and loss of opponens function. Currently, there are numerous intraoperative positioning techniques for arthrodesis which could be confusing for young surgeons. With recent developments of fixation plates and better understanding of the wrist anatomy, this retrospective review aimed to evaluate the efficacy of our intraoperative hand-grip positioning method for arthrodesis of thumb CMCJ OA. What are the postoperative functional outcomes of (1) T-hook plates and (2) our intraoperative hand-grip positioning method for Eaton III thumb CMCJ OA arthrodesis by evaluating pain visual analogue scale (VAS) score, Disabilities of the Arm, Shoulder and Hand questionnaires (DASH), Mayo Wrist scores, capability of thumb opposition (Kapandji score), and comparing pre- and postoperative grip and pinch strength? METHODS: Twenty patients with CMCJ OA underwent arthrodesis using our intraoperative hand-grip positioning method and T-hook plates and screws (Acumed, USA). Patients were evaluated preoperatively and at 1, 3, 6 and 12 months postoperatively. Radiologic assessment including fusion evaluation, evaluation of radial and palmar abduction angles was done on hand X-rays. RESULTS: Twenty patients with a minimum follow-up duration of 12 months were included in this study. 100% fusion rate was achieved with only 1 case of complication involving radial sensory nerve neuropathy which was resolved after removal of implant and neurolysis. Significant improvement in pain and Mayo Wrist scores were noted 3 months postoperatively, whilst DASH score exhibited significant improvements after 6 months of follow-up (p < 0.05). Even though there were no significant differences observed between preoperative and postoperative grip strength, pinch strength and Kapandji scores, positive recovery trends were noted for all parameters with these functions surpassing preoperative levels after 12 months of follow-up. Significant improvements on hand X-rays were also noted for both postoperative radial and palmar abduction angles. CONCLUSIONS: There is currently no consensus on the ideal treatment method for thumb CMCJ OA. In this study, we would like to propose a simple intraoperative hand-grip positioning method with T-hook plates for arthrodesis. As seen from our results, our technique was able to provide satisfactory and replicable postoperative results and thus we would like to propose our hand-grip positioning method with T-hook plates fixation for subsequent treatment of patients with Eaton stage III thumb CMCJ OA.

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.

Synthesis of Spirocyclopropane-Containing 4H-Pyrazolo[1,5-a]indoles via Alkylative Dearomatization and Intramolecular N-Imination of an Indole-O-(Methylsulfonyl)oxime.

In this paper, we report the synthesis of spirocyclopropane-containing 4H-pyrazolo[1,5-a]indoles 6a-e via alkylative dearomatization and intramolecular N-imination of indole-O-(methylsulfonyl)oxime 11. Starting materials tryptophol (7) and 2-bromocyclopetanone (8) were reacted in the presence of HBF4·OEt2, providing 1,2,3,5,6,11-hexahydrocyclopenta[2,3]oxepino[4,5-b]indole (9) in a 63% yield. Compound 9 was reacted with hydroxylamine hydrochloride to afford oxime 10 (65% yield), which was subsequently bis-methanesulfonated to form 11 in a 85% yield. Heating 11 with various alcohols in the presence of N,N-diisopropylethylamine (DIPEA) triggered the alkylative dearomatization and intramolecular N-imination, forming the spirocyclopropane and 4H-pyrazolo[1,5-a]indole structures in the targets 6a-e with 67-84% yields.

Surgical outcomes of anterior lumbar interbody fusion in revision lumbar interbody fusion surgery.

BACKGROUNDS: Anterior lumbar interbody fusion (ALIF) is an attractive option for revision lumbar interbody fusion as it provides wide access for implant removal and accommodation of large interbody grafts for fusion. However, revision lumbar interbody fusion surgery has not been found to result in significantly better functional outcomes compared with other approaches. To date, no prognostic factors of anterior lumbar interbody fusion in revision lumbar interbody fusion have been reported. In this study, we investigated the surgical results and possible prognostic factors of anterior lumbar interbody fusion in revision lumbar interbody fusion. METHODS: Patients who received revision interbody fusion surgery between January 2010 and May 2018 in our hospital were reviewed. Clinical outcomes were determined according to whether the VAS score improvement in back pain and leg pain reached the minimum clinically important difference (MCID) and Macnab criteria. Radiographic outcomes were assessed with fusion rate, preoperative, and postoperative lumbar lordosis. Operative-relative factors that may affect clinical outcomes, such as BMI, existence of cage migration, cage subsidence, pseudarthrosis, previous procedure, and number of fusion segments, were collected and analyzed. RESULTS: A total of 22 consecutive patients who received ALIF for revision interbody fusion surgery were included and analyzed. There were 9 men and 13 women with a mean age at operation of 56 years (26-78). The mean follow-up was 73 months (20-121). The minimal clinically important difference (MCID) was reached in 11 (50%) of the patients for back pain and 14 (64%) for leg pain. According to the modified Macnab criteria, 73% of the patients in this study had successful outcomes (excellent or good). The pain and lumbar lordosis had significant improvement (P < 0.05). Preoperative fusion segment ≥ 2 was shown to be a poor prognostic factor for back pain improvement reaching MCID (P = 0.043). CONCLUSIONS: ALIF has proven effective for revision lumbar fusion surgery, yielding positive clinical and radiographic results. However, having two or more preoperative fusion segments can negatively impact back pain improvement. LEVEL OF EVIDENCE: IV.

Mathematical analysis in the design of digital artery-based V-Y advancement flap in treating proximal interphalangeal joint flexion contracture.

BACKGROUND: The digital artery-based V-Y advancement flap is a widely used flap for soft tissue coverage in the treatment of flexion contracture of the proximal interphalangeal (PIP) joint. A standard method for the flap design and a mathematical method to predict the advance distance have not been well established. In this study, we proposed a simplified method for the design of V-Y advancement flaps based on digital arteries and used a geometric model to predict the advance distance for the flexion contracture correction surgery. METHODS: According to the general concept of hand flap design and law of cosine, we proposed three principles in the design of the digital artery-based V-Y advancement flap that should be followed. Since 2021 to 2022, finger geometric data of 120 fingers (index, middle, ring, and small fingers) from 30 healthy participants were collected and analysed to evaluate the necessary advance distance and flap tip angle for PIP flexion contracture correction of different fingers by our flap design method. RESULTS: The middle finger needed a significantly longer advance distance compared to other fingers in the same degree flexion contracture correction. The ring finger had the largest length-to width ratio and smallest flap tip angle among the four fingers in the V-Y flap design. No vertical scar crossed the flexion creases and flap tip angle < 20° was found in the tentative V-Y flap design for the 120 fingers. CONCLUSIONS: Our flap design method provides a proper advance distance and flap length-to-width ratio without common skin complications in the flap design for PIP flexion contracture of index, middle, ring and small fingers. This geometric model provides a mathematical basis for prediction of advance distance and flap tip angle in the design of a digital artery-based V-Y advancement flap.

Biomechanical study on fixation methods for horizontal oblique metacarpal shaft fractures.

OBJECTIVE: To investigate differences in the effectiveness of two lag screws, a regular bone plate, and locking bone plate fixation in treating horizontal oblique metacarpal shaft fractures. MATERIALS AND METHODS: Horizontal oblique metacarpal shaft fractures were created in 21 artificial metacarpal bones and fixed using one of the three methods: (1) two lag screws, (2) a regular plate, and (3) a locking plate. All the specimens were subjected to the cantilever bending test performed using a material testing machine to enable recording of the force-displacement data of the specimens before failure. The Kruskal-Wallis test was used to compare failure force and stiffness values among the three fixation methods. RESULTS: The mean failure force of the two lag screw group (78.5 ± 6.6 N, mean + SD) was higher than those of the regular plate group (69.3 ± 17.6 N) and locking plate group (68.2 ± 14.2 N). However, the mean failure force did not significantly differ among the three groups. The mean stiffness value of the two lag screw group (17.8 ± 2.6 N/mm) was lower than those of the regular plate group (20.2 ± 10.5 N/mm) and locking plate group (21.8 ± 3.8 N/mm). However, the mean stiffness value did not significantly differ among the three groups. CONCLUSION: The fixation strength of two lag screw fixation did not significantly differ from that of regular and locking bone plate fixation, as indicated by the measurement of the ability to sustain force and stiffness.

Validation and modification of the Coronal Plane Alignment of the Knee classification in the Asian population.

AIMS: The Coronal Plane Alignment of the Knee (CPAK) classification is a simple and comprehensive system for predicting pre-arthritic knee alignment. However, when the CPAK classification is applied in the Asian population, which is characterized by more varus and wider distribution in lower limb alignment, modifications in the boundaries of arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) should be considered. The purposes of this study were as follows: first, to propose a modified CPAK classification based on the actual joint line obliquity (aJLO) and wider range of aHKA in the Asian population; second, to test this classification in a cohort of Asians with healthy knees; third, to propose individualized alignment targets for different CPAK types in kinematically aligned (KA) total knee arthroplasty (TKA). METHODS: The CPAK classification was modified by changing the neutral boundaries of aHKA to 0° ± 3° and using aJLO as a new variable. Radiological analysis of 214 healthy knees in 214 Asian individuals was used to assess the distribution and mean value of alignment angles of each phenotype among different classifications based on the coronal plane. Individualized alignment targets were set according to the mean lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) of different knee types. RESULTS: A very high concentration, 191 from 214 individuals (89.3%), were found in knee types with apex distal JLO when the CPAK classification was applied in the Asian population. By using aJLO as a new variable, the high distribution percentage in knee types with apex distal JLO decreased to 125 from 214 individuals (58.4%). The most common types in order were Type II (n = 70; 32.7%), Type V (n = 55; 25.7%), and Type I (n = 46; 21.5%) in the modified CPAK classification. CONCLUSION: The modified CPAK classification corrected the uneven distribution when applying the CPAK classification in the Asian population. Setting individualized TKA alignment targets according to CPAK type may be a practical method to recreate optimal LDFA and MPTA in KA-TKA. Cite this article: Bone Jt Open 2022;3(3):211-217.

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

BACKGROUND: For oblique metacarpal shaft fracture, if anatomical reduction is achieved through conservative cast immobilization rather than stable fixation, bone malrotation can easily occur, resulting in severe loss in hand prehensile function. However, whether bone plate fixation or only lag screw fixation is more preferable remains unclear. Few studies have evaluated whether screw fixation can provide biomechanical fixation strength similar to bone plate fixation. OBJECTIVE: We assessed the difference in fixation strength between fixtation with two lag screws and bone plate for oblique metacarpal shaft fractures. MATERIALS AND METHODS: We created oblique metacarpal shaft fractures on 21 artificial bones and fixated them using (1) double lag screw (2LS group), (2) regular plate (RP group), or (3) locked plate (LP group). To obtain the force-displacement data, a cantilever bending test was conducted for each specimen through a material testing machine. One-way analysis of variance and a Tukey test were conducted to compare the maximum fracture force and stiffness of the three fixation methods. RESULTS: The maximum fracture force of the 2LS group (mean + SD: 153.6 ± 26.5 N) was significantly lower than that of the RP (211.6 ± 18.5 N) and LP (227.5 ± 10.0 N) groups (p < 0.001). However, no significant differences were discovered between the RP and LP groups. The coefficient of variation for the maximum fracture force of the 2LS group (17.3%) was more than twice as high as that of the RP (8.7%) and LP (4.4%) groups. In addition, the stiffness of the three fixation methods was similar. CONCLUSION: Compared with bone plate fixation, double lag screw fixation yielded slightly lower maximum bearable fracture force but similar stiffness. Therefore, this technique could be used for treating oblique metacarpal shaft fractures. However, using double lag screw fixation alone is technically demanding and requires considerable surgical experiences to produce consistent results.

Midterm Results of Arthroscopy-Assisted "Tent Form" Triangular Fibrocartilage Complex Repair With Dorsal Distal Radioulnar Joint Capsule Imbrication for Posttraumatic Chronic Distal Radioulnar Joint Instability.

PURPOSE: To evaluate the outcomes of "tent form" triangular fibrocartilage complex (TFCC) repair combined with dorsal distal radioulnar joint (DRUJ) capsule imbrication for posttraumatic chronic DRUJ instability. METHODS: All patients treated with arthroscopic "tent form" TFCC repair and DRUJ capsule imbrication from 2016 to 2019 were retrospectively reviewed. The inclusion criteria were symptomatic chronic DRUJ instability for >6 months and dorsal DRUJ subluxation on magnetic resonance imaging. The Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, grip strength, Modified Mayo Wrist Score, range of motion, and distal radioulnar joint stability were assessed for a minimum of 2 years postoperatively. RESULTS: Thirty-eight patients were included in the final analysis. The average follow-up duration was 35.6 months (range, 24-48 months). The 24-month postoperative grip strengths and 3-dimensional motions of wrist were not significantly different from that of the nonoperated wrist. Compared with their preoperative status, Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, and Modified Mayo Wrist Score indicated the significant improvement with P values of .001, .001, and .002, respectively. CONCLUSIONS: In chronic DRUJ instability with a loosening dorsal capsule, "tent form" TFCC transcapsular repair combined with DRUJ capsule imbrication restored the integrity of TFCC and dorsal DRUJ capsule and achieved a promising outcome. We recommend this procedure as an option of treatment for patients with posttraumatic chronic DRUJ instability. LEVEL OF EVIDENCE: IV, case series.

Intermittent parathyroid hormone treatment affects the bone structural parameters and mechanical strength of the femoral neck after ovariectomy-induced osteoporosis in rats.

BACKGROUND: Menopause-induced decline in estrogen levels in women is a main factor leading to osteoporosis. The objective of this study was to investigate the effect of intermittent parathyroid hormone (PTH) on bone structural parameters of the femoral neck in ovariectomized rats, in addition to correlations of maximum fracture force. METHODS: Fifteen female Wister rats were divided into three groups: (1) control group; (2) ovariectomized (OVX) group; and (3) OVX + PTH group. All rats were then killed and the femurs extracted for microcomputed tomography scanning to measure volumetric bone mineral density (vBMD) and bone structural parameters of the femoral neck. Furthermore, the fracture forces of femoral neck were measured using a material testing system. RESULTS: Compared with the control and OVX + PTH groups, the OVX group had significantly lower aBMD, bone parameter, and mechanical strength values. A comparison between OVX and OVX + PTH groups indicated that PTH treatment increased several bone parameters. However, the OVX + PTH groups did not significantly differ with the control group with respect to the bone structural parameters, except for trabecular bone thickness of cancellous bone, which was greater. In addition, among the bone structural parameters, the CSA and BSI of cortical bone were significantly correlated with the maximum fracture force of the femoral neck, with correlations of, respectively, 0.682 (p = 0.005) and 0.700 (p = 0.004). CONCLUSION: Intermittent PTH helped treat ovariectomy-induced osteoporosis of cancellous bone and cortical bone in the femoral necks of rats. The ability of the femoral neck to resist fracture was highly correlated with the two parameters, namely cross-sectional area (CSA) and bone strength index (= vBMD × CSA), of cortical bone in the femoral neck and was less correlated with aBMD or other bone structural parameters.

Biomechanical comparisons of different diagonal screw designs in a novel embedded calcaneal slide plate.

BACKGROUND: Medial displacement calcaneal osteotomy (MDCO) is frequently used for the surgical correction of flatfoot. This study aims to investigate the biomechanical effect of the different diagonal screw design on a novel-designed embedded calcaneal plate for MDCO using finite element analysis (FEA), mechanical test and digital image correlation (DIC) measurement. METHODS: Four groups according to the varied implanted plate were set as control group (Group 1), non-diagonal screw (Group 2), one-diagonal screw (Group 3), and two-diagonal screws groups (Group 4). For FEA, A 450 N load was applied to on the anterior process of the calcaneus from top to bottom. Observational indices included the stress on the cortical and cancellous bone of the calcaneus surrounding the implant, the plate itself as well as screws, and the displacement of the overall structure. In addition, this study also used in vitro biomechanics test to investigate the stiffness of the structure after implantation, and used DIC to observe the displacement of the calcaneus structure after external force. RESULTS: Under a simulated load in FEA, there are significant overall instability and high stress concentration on the calcaneal surrounding host bone and the plate/screws system, respectively, in group 2 compared with other groups. Regard to the mechanical testing with DIC system, significant increased rotation stability, maximum force and stiffness with the addition of diagonal screws. In comparison to Group 2, the increase of 112% and 157% in maximum force as well as 104% and 176% in stiffness were found in Group 3 and 4, respectively. CONCLUSION: For reducing stress concentration and enhancing overall stability, more than one-diagonal screw design is recommended and two-diagonal screws design will be superior. This study provided biomechanical references for further calcaneal implants design to prevent clinical failure after MDCO.

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

ABSTRACT: 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 ±â€Š57.3 N, median + interquartile range) was significantly higher than that of the LP group (227.8 ±â€Š37.5 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 ±â€Š24.6 N/mm) and LP (61.7 ±â€Š19.7 N/mm) groups.Headless compression screws exhibited greater fixability than did locked plates, particularly in its resistance to maximum fracture force.

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.

Direct reduction of high-grade lumbosacral spondylolisthesis with anterior cantilever technique - surgical technique note and preliminary results.

BACKGROUNDS: Surgical reduction for high-grade spondylolisthesis is beneficial for restoring sagittal balance and improving the biomechanical environment for arthrodesis. Compared to posterior total laminectomy and long instrumentation, anterior lumbar inter-body fusion (ALIF) is less invasive and has the biomechanical advantage of restoring the original disk height and increasing lumbar lordosis, thus improving sagittal balance. However, the application of ALIF is still limited in treating low-grade spondylolisthesis. In this study, we developed a new technique termed anterior cantilever procedure to directly reduce the slippage of high-grade lumbosacral spondylolisthesis. The purpose of our study was to investigate the surgical outcomes of the anterior cantilever procedure followed by ALIF and posterior mono-segment instrumented fixation in high-grade spondylolisthesis. METHODS: All patients with high-grade spondylolisthesis who underwent anterior cantilever procedure followed by anterior lumbar inter-body fusion (ALIF) and posterior mono-segment instrumented fixation between November 2006 and July 2017 were enrolled in our study. The slip percentage, Dubousset's lumbosacral angle, pelvic tilt, sacral slope, pelvic incidence, and sagittal alignment were measured pre-operatively and postoperatively at the last follow-up. Surgery time, blood loss, complications, and hospital stay were also collected and analysed. RESULTS: A total of 11 consecutive patients with high-grade spondylolisthesis patients were included and analysed. All of the high-grade spondylolisthesis in our series occurred at the L5-S1 level. The median age was 37 years, and the median follow-up duration was 36 months. The average slip reduction was 30% (60 to 30%, P < 0.01), and the average correction of Dubousset's lumbosacral angle was 13.8° (84.1° to 97.9°, P < 0.01). The median intra-operative blood loss was 300 mL. All patients attained improved sagittal balance after the operation and achieved solid fusion within 9 months after surgery. No incidences of implant failure, permanent neurological deficit, or pseudarthrosis were recorded at the last follow-up. CONCLUSIONS: Anterior cantilever procedure followed by ALIF and posterior mono-segment instrumented fixation is a valid procedure for treating high-grade spondylolisthesis. It achieved a high fusion rate, partially reduced slippage, and significantly improved lumbosacral angle, while minimizing common complications, such as pseudarthrosis, nerve traction injury, excessive soft tissue dissection, and blood loss in posterior reduction procedures. However, posterior instrumentation is still required to the structural stability in the ALIF procedure. LEVEL OF EVIDENCE: IV.

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.

Short-term effect of electroacupuncture on rehabilitation after arthroscopic triangular fibrocartilage complex repair: a randomised study.

BACKGROUND: Electroacupuncture (EA) alleviates chronic pain and acute postoperative pain after several surgical procedures. However, whether EA facilitates postoperative functional recovery after arthroscopic surgery has yet to be determined. This study investigated the short-term effect of EA on a rehabilitation course after arthroscopic triangular fibrocartilage complex (TFCC) repair. METHODS: Forty-two patients undergoing arthroscopic TFCC repair were randomised to an EA group (n = 19) or control group (n = 23). In the EA group, patients received EA treatment and standard active rehabilitation for 4 weeks. In the control group, patients received standard active rehabilitation for 4 weeks. At the end of the treatment and at the follow-up visit 4 weeks after the treatment, Disabilities of the Arm, Shoulder, and Hand (DASH) scores, wrist range of motion (ROM), handgrip strength, and key pinch strength were collected and analysed. RESULTS: The EA group improved significantly than the control group in terms of DASH scores, all wrist motion arcs, and key pinch strength (P < 0.05) at the end of the 4-week treatment and the follow-up visit another 4 weeks later. CONCLUSION: Patients treated with 4 weeks of EA after the arthroscopic TFCC repair had better wrist ROM and DASH scores than patients of control group.

Functional outcomes and complications of hook plate for bony mallet finger: a retrospective case series study.

BACKGROUND: The treatment of mallet fracture using hook plate fixation was first introduced in 2007 and has subsequently shown excellent outcomes. Common complications, such as nail deformity and screw loosening, have also been reported. Very few studies have focused on these common complications or their prevention. In this study, we present the clinical outcomes and complications of our case series and describe the pitfalls and detailed solution of surgical tips to avoid common complications related to this procedure. METHODS: The retrospective case series of 16 patients with mallet fractures who underwent open reduction and hook plate fixation in our hospital from 2015 to 2020 were retrospectively reviewed. Data on extension lag, range-of-motion (ROM) of the distal interphalangeal joint (DIP) joint, the Disabilities of the Arm, Shoulder, and Hand (DASH) score, and surgical complications were collected and analysed. The clinical outcome was graded according to the Crawford mallet finger criteria. RESULTS: Sixteen patients were included in our analysis. The median DIP extension lag was 0° (range, 0° to 30°) and the median active DIP flexion angle was 60° (range, 40° to 90°). The median DASH score was 0 (range, 0-11.3). Fourteen patients with good and excellent results were satisfied with this treatment. The Complication rate in our patient series was 18%. Common complications reported in articles included wound necrosis, extension lag, nail deformity, and plate loosening. CONCLUSIONS: Despite the fact that the treatment of mallet fracture with hook plate fixation has satisfactory functional outcomes, pitfalls, including iatrogenic nail germinal matrix injury, unnecessary soft tissue dissection, and insufficient screw purchase, were still reported. To avoid complications, we suggest modifications of the skin incision, soft tissue dissection, and screw position.

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

BACKGROUND: Metacarpal shaft fracture is a common fracture in hand trauma injuries. Surgical intervention is indicated when fractures are unstable or involve considerable displacement. Current fixation options include Kirschner wire, bone plates, and intramedullary headless screws. Common complications include joint stiffness, tendon irritation, implant loosening, and cartilage damage. OBJECTIVE: We propose a modified fixation approach using headless compression screws to treat transverse or short-oblique metacarpal shaft fracture. MATERIALS AND METHODS: We used a saw blade to model transverse metacarpal neck fractures in 28 fresh porcine metacarpals, which were then treated with the following four fixation methods: (1) locked plate with five locked bicortical screws (LP group), (2) regular plate with five bicortical screws (RP group), (3) two Kirschner wires (K group), and (4) a headless compression screw (HC group). In the HC group, we proposed a novel fixation model in which the screw trajectory was oblique to the long axis of the metacarpal bone. The entry point of the screw was in the dorsum of the metacarpal neck, and the exit point was in the volar cortex of the supracondylar region; thus, the screw did not damage the articular cartilage. The specimens were tested using a modified three-point bending test on a material testing system. The maximum fracture forces and stiffness values of the four fixation types were determined by observing the force-displacement curves. Finally, the Kruskal-Wallis test was adopted to process the data, and the exact Wilcoxon rank sum test with Bonferroni adjustment was performed to conduct paired comparisons among the groups. RESULTS: The maximum fracture forces (median ± interquartile range [IQR]) of the LP, RP, HC, and K groups were 173.0 ± 81.0, 156.0 ± 117.9, 60.4 ± 21.0, and 51.8 ± 60.7 N, respectively. In addition, the stiffness values (median ± IQR) of the LP, HC, RP, and K groups were 29.6 ± 3.0, 23.1 ± 5.2, 22.6 ± 2.8, and 14.7 ± 5.6 N/mm, respectively. CONCLUSION: Headless compression screw fixation provides fixation strength similar to locked and regular plates for the fixation of metacarpal shaft fractures. The headless screw was inserted obliquely to the long axis of the metacarpal bone. The entry point of the screw was in the dorsum of the metacarpal neck, and the exit point was in the volar cortex of the supracondylar region; therefore the articular cartilage iatrogenic injury can be avoidable. This modified fixation method may prevent tendon irritation and joint cartilage violation caused by plating and intramedullary headless screw fixation.