ABSTRACT
Each of the syndesmotic ligaments has different biomechanical effects. Minimal movement occurs in the syndesmosis during the motion of the ankle joint, and the syndesmotic injury is associated with the ankle position and the patterns of external forces. Controversy still exists with respect to the optimal fixation of the syndesmosis. Malreduction of the syndesmosis would lead to abnormal pressure distribution on the ankle joint. Therefore, the flexible fixation might more accord with the physical movement of the syndesmosis. In this article, the biomechanical studies on syndesmosis are reviewed to provide the reference for proper treatment method for syndesmotic injury.
ABSTRACT
The surgical management to the injuries of the fourth and fifth tarsometatarsal [TMT] joints is controversial. We briefly review the anatomical characteristics to the injuries, the diagnosis, as well as the individualized treatment of the injuries of the fourth and fifth TMT joints by open reduction and internal fixation, TMT arthrodesis and arthroplasty. We conclude that open reduction and internal fixation is the recommended option for acute injuries, while arthrodesis can be used in cases of malunion of the fourth and fifth TMT joints with gross pain or arthritic changes and obvious structural deformity. Arthroplasty is an effective salvage operation mainly used in high-demand patients with severe TMT arthritis. Finally, we propose a recommended treatment algorithm [based on the literature and our experience], taking into account the specific indications for internal fixation, TMT arthrodesis and arthroplasty to optimize the individualized treatment
Data sources /Study selection: Data from survey reports, descriptive, cross-sectional and longitudinal studies published from 2002 to 2012 on the topic of the injuries to the fourth and fifth tarsometatarsal joint on human and radiography studies were included
Data Extraction: The data was extracted from online resources of American Orthopaedic Foot and Ankle Society, American Academy of Orthopaedic Surgeons, US National Library of Medicine, The MEDLINE
Conclusion: It is important to comprehend the specific anatomical characteristics and grasp the strict indications, advantages and disadvantages of the ORIF, TMT arthrodesis and arthroplasty to optimize the individualized treatment of the fourth and fifth TMT joints injuries in a maximum extent
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<p><b>OBJECTIVE</b>To discuss operative methods and effects for Müller-Weiss disease.</p><p><b>METHODS</b>From March 2005 to May 2011, 15 patients were operated. There were 2 males and 13 females, with an average age of 51.8 years (range, 26 to 62 years). The preoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was (42 ± 13) points. According to the Maceira Staging system, 1 foot was grade 2, 6 feet were grade 3, 4 feet were grade 4, and 4 feet were grade 5. The technique consisted of arthrodesis of the talonaviculocuneiform joints with plate, arthrodesis of the talonavicular joint and arthrorisis of naviculocuneiform joint with plate, or triple arthrodesis with screws, according to the preoperative evaluation.</p><p><b>RESULTS</b>Ten feet were treated with arthrodesis of the talonaviculocuneiform joints, 3 feet were treated with arthrodesis of the talonavicular joint and arthrorisis of naviculocuneiform joint and 2 feet were treated with triple arthrodesis. Two patients were lost to follow-up. The average follow-up after operation was 19.2 months (range, 9 to 38 months). All feet were solid fusion and the average duration of union was 13.3 weeks (range, 12-16 weeks). The AOFAS ankle-hindfoot score at the last follow-up was (83 ± 6) points. Two feet were excellent, 10 feet were good, and 1 foot was fair. The length of feet was (14.2 ± 1.0) cm before surgery and (15.7 ± 0.9) cm at the last follow-up (t = 11.570, P < 0.05). The Meary's angle was -6.1° ± 13.1°before surgery and 1.1° ± 3.0° at the last follow-up (t = 2.248, P < 0.05). The talocalcaneal angle was 4.5° ± 2.2° before surgery and 18.0° ± 4.0° at the last follow-up (t = 11.700, P < 0.05). One foot had breakage of the plate and screws at arthrorisis of naviculocuneiform joint and none had complications related to the incision.</p><p><b>CONCLUSION</b>Operations for Müller-Weiss disease, according to concrete conditions using different therapeutic program, may achieve a satisfactory outcome.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Arthrodesis , Methods , Bone Nails , Bone Plates , Follow-Up Studies , Foot Diseases , General Surgery , Scaphoid Bone , General Surgery , Treatment OutcomeABSTRACT
Adult-acquired flatfoot deformity (AAFD), which is mainly caused by posterior tibial tendon dysfunction (PTTD), is a common foot and ankle disease, and most of the deformities are flexible. How to explain the pathogenesis of AAFD and choose proper surgical treatment for the deformity has become a hot research focus nowadays. With the development of in vitro modeling technique for flatfoot, the accuracy and repeatability of the biomechanical tests have been gradually recognized, and the research results have also provided important theoretical basis for the clinical treatment of flatfoot deformity. In this article, the biomechanical mechanism of AAFD caused by PTTD, and the various modeling methods of flatfoot based on cadaver or finite element model were veviewed. The biomechanical characteristics of different reconstruction procedures in relative basic researches on flatfoot deformity were also analyzed and compared. The author believes that on the basis of simulating the dynamic stability of foot by tendon loading, the in vitro model of flexible flatfoot established by selective ligaments section is more reliable, and the reconstruction procedure adopted by various flatfoot models has different biomechanical characteristics. The soft tissue reconstruction and the bony procedures should be performed at the same time, and individual bony procedures should be chosen based on the degree and feature of the deformity.
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<p><b>BACKGROUND</b>There is lack of consensus regarding the best option for the treatment of acute Achilles tendon rupture-operation or non-operation. The purpose of this meta-analysis was to identify and summarize the randomized controlled trials comparing the operative and non-operative lines of treatment of acute Achilles tendon ruptures.</p><p><b>METHODS</b>We searched multiple databases in English (including EMBASE, PubMed, and OVID) and in Chinese (including CNKI, WANFANG, and VIP), as well as reference lists of articles and main orthopaedic and sports medical journals. Two reviewers independently screened the studies for eligibility, evaluated the quality and extracted data from eligible studies, with confirmation by cross-checking. The major results and conclusions were concluded, and the different complication rates and functional outcomes were compared. Meta-analysis was processed by RevMan 5.0 software.</p><p><b>RESULTS</b>Eight randomized controlled trials (RCTs) involving 777 patients met the inclusion criteria. The rerupture rate in non-operative group was significantly higher (Z = 3.33, P < 0.01). However, the moderate (Z = 4.27, P < 0.01) and minor (Z = 5.59, P < 0.01) complication rate in the operative group were significantly higher. No significant difference in comparing the major and total complication rates. The return to work time in the operative group was shorter (Z = 2.65, P < 0.01). The inability to return to previous level sporting rate and ankle joint decreased range of motion (ROM) rate showed no significant difference in the two groups. Other functional outcomes were similar in the two groups.</p><p><b>CONCLUSIONS</b>Operation could significantly reduce the risk of rerupture; however, it was associated with a higher risk of other complications. The functional outcomes were similar in two treatment methods except an earlier return to work in patients treated operatively. Thus operative treatment is preferable for patients with good physical condition. Non-operative treatment is an acceptable alternative especially for the older and patients with lower sporting requirements.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Achilles Tendon , Wounds and Injuries , General Surgery , Randomized Controlled Trials as Topic , Range of Motion, Articular , Physiology , Tendon Injuries , General SurgeryABSTRACT
<p><b>BACKGROUND</b>As precise positioning of ankle radiography is not possible, quantitative measurement of all syndesmotic parameters on repeated ankle X-ray films may be of little value. The purpose of this study was to provide a set of scientific and objective evaluation criteria for assessing the quality of ankle fracture reduction accurately and reliably by an intelligent combining three-dimensional (3-D) computed tomography (CT) measurement model.</p><p><b>METHODS</b>From June 2008 to March 2011, all the thin-slice CT images of 100 cases (50 males and 50 females) with normal ankle joint scanned by 16-slice spiral CT were collected. Two-dimensional (2-D) and 3-D images of ankle joints were generated by using multiple planar reconstruction (MPR) and surface shaded display (SSD) respectively. The relevant parameters about bone structures and their relationship were measured and analyzed based on 3-D topological narrow division technique and 3-D measurement techniques combining essential elements of point, line and surface.</p><p><b>RESULTS</b>In this study, the mean distance from lateral malleolus tip to talocrural articular surface, the tip of medial malleolus anterior colliculus to talocrural articular surface and lateral malleolus tip to the tip of medial malleolus anterior colliculus were (22.83 ± 1.12) mm, (12.84 ± 1.09) mm, and (61.18 ± 2.03) mm respectively in male group, and (20.16 ± 1.00) mm, (10.30 ± 1.05) mm and (53.00 ± 1.40) mm respectively in female group. The above three parameters were correlated with gender, height and weight (P < 0.05). However, the mean perpendicular distance from lateral malleolus tip to the plane through the tip of medial malleolus anterior colliculus, the talocrural angle, later clear space, medial clear space, and the superior clear space were (9.93 ± 0.29) mm, (10.01 ± 0.38)°, (1.94 ± 0.16) mm, (2.78 ± 0.19) mm, and (3.14 ± 0.15) mm respectively in 100 cases, were not significance correlated with gender, height and weight (P > 0.05).</p><p><b>CONCLUSIONS</b>This study could provide a certain amount of relevant data for the standard of injured ankle anatomical reduction and the second surgery planning after malunion. The methods of measurement are reliable, reproducible, and easy to apply in practice.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Ankle Joint , Diagnostic Imaging , Image Processing, Computer-Assisted , Methods , Tomography, X-Ray Computed , MethodsABSTRACT
<p><b>OBJECTIVES</b>A retrospective study was used to evaluate the short to intermediate outcomes of open reduction and internal fixation of acute Lisfranc joint injuries.</p><p><b>METHODS</b>From January 2003 to December 2009, 47 patients with Lisfranc injuries were treated in the study,41 patients were analyzed in current study with an average age of thirty-one years old. All of patients were treated with open reduction and internal fixation. According to the Myerson classification system, there were 9 type-A fractures, 7 type-B1, 11 type-B2, 10 type-C1, 5 type-C2. The AOFAS scale and VAS scale were used for the outcome measurement at the final follow-up.</p><p><b>RESULTS</b>There were 41 patients with 42 operations were followed up and with a mean time of 36 months (ranged, 12 to 71 months). The mean AOFAS score was (84.2 +/- 2.8) points (ranged, 65 to 100 points), with an excellent and good rate of 81 percent. The mean VAS score was (2.6 +/- 0.5) points (ranged, 0 to 6 points). Three patients developed superficial infection, and two developed skin necrosis. Nineteen patients had weight-bearing or walking pain. All of the patients had radiographic evidence of degenerative change, four with malunion of the second tarsometatarsal joint, and two of the patients with hallux valgus deformity change.</p><p><b>CONCLUSION</b>According to the results of the study, anatomic reduction and internal fixation can get the satisfactory results for the treatment of acute Lisfranc injuries during a short to intermediate follow-up time. All of the patients would have different degree of tarsometatarsal joint degenerative changes, but these changes are non-progressive and associated with minimal loss of function.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Acute Disease , Fracture Fixation, Internal , Methods , Fractures, Bone , General Surgery , Joint Dislocations , General Surgery , Ligaments, Articular , Wounds and Injuries , Metatarsal Bones , General Surgery , Retrospective Studies , Tarsal Joints , Wounds and Injuries , General SurgeryABSTRACT
<p><b>OBJECTIVES</b>To provide a cumulative data about the complications of second or third generation ankle prostheses in the literature, and to provide a summary high-grade complications associated with implant failure.</p><p><b>METHODS</b>A comprehensive search for all relevant articles published in English from January 1995 to December 2010 was conducted. Two reviewers evaluated each study to determine whether it was eligible for inclusion and collected the data of interest. Meta-analytic pooling of results across studies was performed for the complications and failure rate.</p><p><b>RESULTS</b>Thirty-five primary studies with 4395 implants were identified. The three highest complications of total ankle arthroplasty were aseptic loosening (12.51%), intra-operative bone fracture (11.97%) and bony impingement (11.27%). The three high-grade complications associated with implant failure were aseptic loosening (45.00%), infection (33.00%) and malalignment (29.00%). The pooled mean failure rate was 10.98% (95%CI: 8.80% - 13.16%), and the pooled mean failure rate of STAR implant was 14.20% (95%CI: 10.64% - 17.76%).</p><p><b>CONCLUSIONS</b>It is found that aseptic loosening, infection and malalignment are high-grade complications associated with implant failure in total ankle arthroplasty. The orthopaedic surgeons should be more careful in the operation, and the patients should coordinate with the post-operative rehabilitation plan.</p>
Subject(s)
Humans , Arthroplasty, Replacement, Ankle , Joint Prosthesis , Postoperative Complications , Prosthesis FailureABSTRACT
<p><b>OBJECTIVE</b>To discuss the characteristics and experience for surgical treatment of combined calcaneal fracture.</p><p><b>METHODS</b>Between February 2004 and September 2007, 17 feet of 13 patients with combined calcaneal fractures underwent surgical operations. Among 17 calcaneal fractures, 8 combined with ipsilateral talus fractures, 5 combined with trimalleolar fractures, 4 combined with Pilon fractures. Firstly, fractures of hinder foot were treatment with open reduction and internal fixation according to the principle. Of all, 15 fractures were treated with screws or titanic plate plus open reduction and internal fixation, the rest 2 fractures were treated with subtalar arthrodesis. Postoperative X-ray assessed the internal fixation and union of fractures. The foot function was evaluated by the Maryland Foot Score.</p><p><b>RESULTS</b>A total of 13 patients were all followed up for 16.0 - 33.0 months (average 26.5 months), superficial infection was found in a patient with open wound 10 d after surgery. All the bone fractures united after surgery from 4 to 6 months. Morphous improvement of the calcaneal were proved by X-ray films and there here was no plates and screws' breakage, loosening. Mild osteoarthritis in Subtalar and ankle joints were found by X-ray after surgery from 9 months to last follow-up. Cystic degeneration and necrosis were found in 5 and 2 cases of talus fractures respectively. According to Maryland Foot Score, excellent was in 3 feet, good in 6 feet, fare in 5 feet and poor in 3 feet, with excellence rate of 52.9%.</p><p><b>CONCLUSIONS</b>Combined calcaneal is a calcaneus-based concomitant ankle and foot fractures after a high-energy injury. Good deal of soft tissue and correct design of operation pre-operatively, restoration of form and power lines of calcaneal, effective bone graft, right place of simple internal fixation or subtalar arthrodesis and good reduction and internal fixation of other fracture in hinder feet intra-operatively and correct function postoperatively are key points to have a relatively satisfied treating effect of combined calcaneal fractures.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Young Adult , Calcaneus , Wounds and Injuries , Follow-Up Studies , Fracture Fixation, Internal , Methods , Fractures, Bone , General Surgery , Treatment OutcomeABSTRACT
<p><b>OBJECTIVES</b>To evaluate the characteristic morphology of heel spur, and to investigate the relationship of heel spur and plantar heel pain.</p><p><b>METHODS</b>From June 2005 to April 2009, 210 cases (254 feet) with heel spur (according to Denis Pain Scale) were divided into cases group 1 (P2, n = 46), 2 (P3, n = 44), 3 (P4, n = 42), 4 (P5, n = 36) and controls group (P1, n = 42). Three-dimensional reconstruction of heel spur was performed in all groups using volume rendering based on multi-slice CT data by Super Image orthopedics edition 1.0. The characteristic morphology of heel spur was observed and the data were measured and analyzed, involving the width of basilar part, the length, the angle between heel spur and planta pedis, and the angle between the longitudinal axis of calcaneus and heel spur.</p><p><b>RESULTS</b>Parts of cases groups displayed coarse arcuate edge and undersurface with one or more little heel spurs adhere to heel spur, of which the numbers were greater than controls group, especially in cases group 4. No significant difference of the width of basilar part of heel spur was found among 5 groups (F = 2.32, P > 0.05). However, obvious difference was found in the length, the angle between heel spur and planta pedis, and the angle between the longitudinal axis of calcaneus and heel spur (F = 8.23, 6.82, 5.87, P < 0.05). Compared with the controls group, the angle between heel spur and planta pedis of cases groups had higher degrees, but the difference of the other data presented irregular.</p><p><b>CONCLUSIONS</b>The characteristic morphology of heel spur varies in patients associated with plantar heel pain. No correlation is found between the severity and the morphological data, including the width of basilar part, the length, the angle between heel spur and planta pedis, and the angle between the longitudinal axis of calcaneus and heel spur.</p>
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Calcaneus , Diagnostic Imaging , Pathology , Case-Control Studies , Heel Spur , Diagnostic Imaging , Pathology , Imaging, Three-Dimensional , Tomography, X-Ray ComputedABSTRACT
<p><b>OBJECTIVE</b>Review the series cases of open calcaneal fractures, to discuss the clinical outcome and evaluate the effective factors associated with the prognosis.</p><p><b>METHODS</b>Between 2004 and October 2009, 427 calcaneal fractures were treated, 22 of these fractures were open, 15 feet of 15 patients were available for the follow-up. There were 9 males and 6 females with a mean age of 34.7 years (range 18 to 66). According to the Sanders classification, there were 2 type I fractures, 3 type II, 6 type III and 4 type IV. According to the Gustilo classification, there were 1 of type 1, 4 of type II, 5 of type III A, and 5 of type III B open fracture. According to the open calcaneal injury subtypes (OCIS), there were 1 of type IA, 2 of type II A,7 of type II B, 2 of type IIIA and 3 of type III B. All patients were treated with intravenous antibiotics, immediate and repeat irrigation and debridement, temporary wound coverage, and initial stabilization of the limb. Clinical examination, radiographs and AOFAS ankle-hindfoot scores were used for outcome measurement.</p><p><b>RESULTS</b>The average follow-up time was 16.4 months (8 to 31 months). The mean AOFAS score was (74.6 +/- 10.4) (range 58 to 94). There were 4 feet required tissue transfer for wound coverage. An infection developed at the sites of 5 fractures,4 of witch were Gustilo type III, 2 deep infections with osteomyelitis developing at the site of 1 patient, no patient required amputation.</p><p><b>CONCLUSION</b>These findings do not reflect as high a deep infection and osteomyelitis rate for open calcaneal fractures as previously reported, if early and satisfying debridement, evaluate the soft tissue injury carefully, and choose the right time and indications for internal fixation. In addition, early internal fixation should be avoided for Gustilo type III and OCIS type B calcaneal fractures.</p>
Subject(s)
Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Calcaneus , Wounds and Injuries , Follow-Up Studies , Fractures, Bone , General Surgery , Postoperative Complications , Time FactorsABSTRACT
<p><b>OBJECTIVE</b>To explore the operative methods of malunited or nonunited talus fractures.</p><p><b>METHODS</b>Twenty-two patients of malunions or nonunions after displaced talar fractures were treated from January 2000 to January 2008. There were 17 males and 5 females with an average age of 34 years (ranged from 15 to 52 years). According to classification of posttraumatic talar deformities (Zwipp 2003), there were 10 cases of type I (malunion and/or joint displacement), 8 cases of type II (nonunion with joint displacement), 4 cases of type III (type I/II with partial AVN). The surgical treatments included open reduction, osteotomy, correction and internal fixation with plate, screw or K-wire, or the ankle, subtalar arthrodesis.</p><p><b>RESULTS</b>Seventeen patients were followed up for 14 months in average (ranged from 12 to 24 months). No wound healing problems or infections were observed. Solid union was obtained without redislocation in all patients. The mean time of bone union was 14 weeks (ranged from 12 to 18 weeks). The mean time of completely weight loading was 14 weeks (ranged from 12 to 18 weeks). The mean AOFAS ankle and hindfoot score increased from 35.4 (ranged from 28.0 to 41.0) to 86.6 (ranged from 78.0 to 98.0).</p><p><b>CONCLUSIONS</b>As to posttraumatic talar deformities, surgical treatment can lead to a favorable outcome. According to concrete status of malunions or nonunions after displaced talar fractures, suitable surgical treatment should be applied to obtain satisfactory outcome.</p>
Subject(s)
Adolescent , Adult , Female , Humans , Male , Middle Aged , Young Adult , Arthrodesis , Follow-Up Studies , Fracture Fixation, Internal , Fracture Healing , Fractures, Bone , General Surgery , Osteotomy , Talus , Wounds and Injuries , General Surgery , Treatment OutcomeABSTRACT
<p><b>BACKGROUND</b>Subtalar joint (STJ) neutral position is the position typically used by clinicians to obtain a cast representation of a patient's foot before fabrication of biomechanical functional orthosis. But no method for measuring STJ neutral position has been proven accurate and reproducible by different testers. This study was conducted to investigate the STJ neutral position in normal feet in cadavers.</p><p><b>METHODS</b>Twelve fresh-frozen specimens of amputated lower legs were used. Pressure-sensitive films were inserted into the anterior and posterior articulation of STJ. The contact areas for various foot positions and under axial loads of 600 N were determined based on the gray level of the digitized film. The STJ neutral positions were determined as the ankle-foot position where the maximum contact area was achieved, because the neutral position of a joint was defined as the position where the concave and convex surfaces were completely congruous.</p><p><b>RESULTS</b>In ankle-foot neutral position, the contact area of STJ was (2.79 +/- 0.24) cm(2). In the range of motion of adduction-abduction (ADD-ABD), the maximum contact area was (3.00 +/- 0.26) cm(2) when the foot was positioned 10 degrees of ABD (F = 221.361, P < 0.05). In the range of motion of dorsiflexion-plantarflexion (DF-PF), the maximum contact area was (3.61 +/- 0.25) cm(2) when the foot was positioned 20 degrees of DF (F = 121.067, P < 0.05). In the range of motion of inversion-eversion (INV-EV), the maximum contact area was (3.14 +/- 0.26) cm(2) when the foot was positioned 10 degrees of EV (F = 256.252, P < 0.05).</p><p><b>CONCLUSIONS</b>Joints, such as STJ, therefore, are not necessarily in neutral position when the ankle-foot is placed in the traditional concept of neutral position. The results demonstrate that the most approximate STJ neutral position was in the foot position of 10 degrees of abduction, 20 degrees of dorsiflexion and 10 degrees of eversion.</p>
Subject(s)
Humans , Cadaver , Range of Motion, Articular , Subtalar JointABSTRACT
<p><b>OBJECTIVE</b>To analyze the pelvic stability after type I resection of iliac tumor.</p><p><b>METHODS</b>Six adult cadaveric specimens were tested. The iliac subtotal resection models were established according to Ennecking's type I resection. Markers were affixed to the key region of the pelves. Axial loading from the proximal lumbar was applied by MTS load cell in the gradient of 0-500 N in the double feet standing state. Images in front view were obtained using CCD camera. Based on Image J software, displacements of the first sacral vertebrae (S1) of the resected pelves and the intact pelves were calculated using digital marker tracing method with center-of-mass algorithm.</p><p><b>RESULTS</b>Serious instabilities were found in the resected pelves. S1 rotational movements around the normal side femoral head of the resected pelvis were found. The average vertical displacement of S1 of the resected pelvis was (7 +/- 3) mm under vertical load of 500 newtons, which were 8.3 times compared to the intact pelvis. The average angle of S1 rotation around the normal side femoral head of the resected pelvis was (4.0 +/- 1.8) degrees, which were 12.5 times compared to the intact pelvis.</p><p><b>CONCLUSIONS</b>Biomechanical model of type I resection of iliac tumor are established. Essential pelvic reconstruction must be introduced because of the serious instability of the bone defection after tumor resection.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Biomechanical Phenomena , Bone Neoplasms , General Surgery , Ilium , Wounds and Injuries , Models, Biological , Pelvis , Range of Motion, ArticularABSTRACT
<p><b>BACKGROUND</b>The pelvis often needs to be reconstructed after bone tumor resection. A major challenge here for the orthopedic surgeons is to choose a method that gives the best performance which depends upon its biomechanical properties. In this study, a 3-dimensional finite element analysis (FEA) was used to analyze the biomechanical properties of reconstructed pelvis using fibula transplant fixed by four commonly used rod-screw systems.</p><p><b>METHODS</b>A total pelvic finite-element model including the lumbar-sacral spine and proximal femur was constructed based on the geometry of CT image from a healthy volunteer. Three-dimensional finite element models of different implants including fibula, rod and screw were simulated using ways of solid modeling. Then various reconstructed finite element models were assembled with different finite element implant model and type I resected pelvic finite element model. The load of 500 N was imposed vertically onto the superior surface of L3 vertebral body, and the pelvis was fixed in bilateral leg standing positions. FEA was performed to account for the stress distribution on the bones and implants. The pelvis displacement of the different rod-screw fixation methods and the maximum equivalent stress (max EQV) on all nodes and element were figured out to evaluate the advantages and disadvantages of different reconstructive methods.</p><p><b>RESULTS</b>Stress concentration in the fibula transplant was extremely high in the reconstructed pelvis, but could be substantially decreased by internal fixation, which partially transferred the stress from the fibula to the rod-screw systems. High stress concentration was also found in the implants, especially in the connection sites between screw and rod. Among the four methods of fixation, a double rod system with L5-S1 pedicle and ilium screws (L5-S1 HR) produced the best performance: least stress concentrations and least total displacement.</p><p><b>CONCLUSION</b>According to the stability and stress concentration, the method of L5-S1 HR fixation combined with fibula transplantation is better than other fixation methods in pelvic reconstruction after type I resection.</p>
Subject(s)
Adult , Humans , Male , Biomechanical Phenomena , Bone Neoplasms , General Surgery , Bone Screws , Femur Neck , General Surgery , Fibula , Transplantation , Finite Element Analysis , Pelvic Bones , General Surgery , Plastic Surgery Procedures , MethodsABSTRACT
Objective To compare the survival rate of two kinds of neurovenofasciocutaneous flaps and investigate the venous reverse flow of flaps.MethodsTen New Zealand White rabbits were randomly allocated into 2 groups of 10 flaps(group A: the lesser saphenous sural pedicled fasciocutanous flaps,blood supply provided with perforator arteries;group B: the lesser saphenous sural pedicled fasciocutanous flaps,blood supply provided with axial type artery).The survival rate of flaps in two groups was observed.Pedicles of flaps were harvested and examined histologically.ResultsThe survival rate of flaps in group A was significantly lower than that in group B[(15.2?16.7)% vs(94.1?6.4)%,P
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[Objective]To discuss the effect of the calcaneocuboid arthrodesis on kinematics of foot and its clinical signifi-cance.[Method]In 10 fresh-frozen foot specimens,limitation dorsiflexion, plantoflexion, abduction, adduction , eversion, inver-sion motion of foot were determined before and after calcaneocuboid arthrodesis under non-weight with moment of couple, bendingmoment, equilibrium dynamic loading.[Result]A significant decrease in the motion of foot was observed (P
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Objective To introduce the clinical experience and investigate venous drainage of distal- ly-based dorsal digital neurocutaneous flap for finger-pulp reconstruction.Methods From Mar.2004 to Oct.2005,18 patients with traumatic finger-pulp defect (>2cm) were treated by distally based dorsal ho- modigital neurocutaneous flaps.The flap measured 2 cm?2cm~3cm?4cm with the neuro-veno-adipal ped- icle 1cm wide and 2~3cm long.The pivot points were proximal to the PIP joints.The dorsal digital nerve was neurorrhaphied with the proper digital nerve of the recipient site.The dorsal digital vein was ligated at 1cm distal to the pivot point to prevent venous ingress.No venous anastomosis was performed.Results All the flaps survived but had some degrees of venous congestion and swelling,and 8 flaps developed tension blisters. In 13 flaps with follow-up more than 6 months,protective sensation was restored.Conclusion Dorsal digit- al neurocutaneous flap is simple and effective for finger-pulp reconstruction.Ligating the big superficial vein at the distal base to interrupt venous ingress,and allowing the proximal vein open and venous egress,can reduce flap congestion and swelling.
ABSTRACT
Objective To discuss the effect of the calcaneocuboid joint arthrodesis on the weight- bearing area of subtalar joint and its clinical significance.Methods Twelve fresh-frozen cadaver foot specimens were used for determination of weight-bearing area of the subtalar joint on foot and ankle neutral position,dorsiflexion,plantoflexion,adduction,abduction,inversion and eversion motion by means of pressure sensitive film before and after calcaneocuboid joint arthrodesis under weight loading.Results Weight-bearing area of the subtalar joint averagely increased for (32.54?7.45)% in all positions after calcaneocuboid joint arthrodesis,with statistical significance (P<0.05).Conclusion Weight-bear- ing area of the subtalar joint increases after calcaneocuboid joint arthrodesis,which contributes to decrea- sing the pressure and increasing the stability of the subtalar joint.