Guang-rong Yu

Deformation and stress distribution of the human foot after plantar ligaments release: a cadaveric study and finite element analysis.

The majority of foot deformities are related to arch collapse or instability, especially the longitudinal arch. Although the relationship between the plantar fascia and arch height has been previously investigated, the stress distribution remains unclear. The aim of this study was to explore the role of the plantar ligaments in foot arch biomechanics. We constructed a geometrical detailed three-dimensional (3-D) finite element (FE) model of the human foot and ankle from computer tomography images. The model comprised the majority of joints in the foot as well as bone segments, major ligaments, and plantar soft tissue. Release of the plantar fascia and other ligaments was simulated to evaluate the corresponding biomechanical effects on load distribution of the bony and ligamentous structures. These intrinsic ligaments of the foot arch were sectioned to simulate different pathologic situations of injury to the plantar ligaments, and to explore bone segment displacement and stress distribution. The validity of the 3-D FE model was verified by comparing results with experimentally measured data via the displacement and von Mise stress of each bone segment. Plantar fascia release decreased arch height, but did not cause total collapse of the foot arch. The longitudinal foot arch was lost when all the four major plantar ligaments were sectioned simultaneously. Plantar fascia release was compromised by increased strain applied to the plantar ligaments and intensified stress in the midfoot and metatarsal bones. Load redistribution among the centralized metatarsal bones and focal stress relief at the calcaneal insertion were predicted. The 3-D FE model indicated that plantar fascia release may provide relief of focal stress and associated heel pain. However, these operative procedures may pose a risk to arch stability and clinically may produce dorsolateral midfoot pain. The initial strategy for treating plantar fasciitis should be non-operative.

Treatment of femoral subtrochanteric fractures with proximal lateral femur locking plates.

OBJECTIVE: To study the outcome of subtrochanteric hip fractures treated with proximal lateral femur locking plate. METHOD: We retrospectively reviewed the clinical results of 48 cases of femoral subtrochanteric fractures treated with proximal lateral femur locking plates from January 2008 to May 2010. The progress of fracture healing, as well as the occurrence of complications, was recorded. The function of the hip joint was evaluated by the Harris social index and the Parker and Palmer mobility score one year after the operation. RESULT: 45 patients were followed up until fracture union or a revision surgery. Among the 45 patients, 43 patients obtained fracture union without further intervention. Thirty-eight fractures healed with no loss of position at 1-year follow-up. There were no cases of hip screw cutting through the femoral head. The mean score of the Harris social index was 86.5±9.8 (73~95). The mean Parker and Palmer mobility score was 7.4±2.1 (3~9). CONCLUSION: The proximal lateral femur locking plate is the kind of stable and effective internal fixation for treating subtrochanteric hip fractures which has the advantage of stable fixation especially for the lateral femoral wall fracture. Level of Evidence IV, Case Series.

Biomechanical Analysis of the Calcaneocuboid Joint Pressure After Sequential Lengthening of the Lateral Column

Background: Lengthening of the lateral column by means of the Evans osteotomy is commonly used for reconstruction of adult and pediatric flatfoot. However, some reports have shown that the Evans osteotomy is linked with increased calcaneocuboid joint pressures and an increased risk of arthritis in the joint. The purpose of this study was to measure the pressure across the calcaneocuboid joint and demonstrate the changing trends of the pressure within the calcaneocuboid joint after sequential lengthening of the lateral column. Methods: Six cadaver specimens were physiologically loaded and the peak pressure of the calcaneocuboid joint was measured under the following conditions: (1) normal foot, (2) flatfoot, and (3) sequential lengthening of the lateral column by means of the Evans procedure (from 4 mm to 12 mm, in 2 mm increments). Results: Peak pressures across the joint increased significantly from baseline in the flatfoot (P < .05). In the corrected foot, with the increment of the graft, the peak pressure decreased initially and then increased. The pressure reached its minimum value (11.04 ± 1.15 kg/cm2) with 8 mm lengthening of the lateral column. The differences were significant compared to the flatfoot (P < .05) and corrected foot with the other sizes of grafts (P < .05), but differences were not significant compared to the intact foot (P = .143). Conclusions: Lateral column lengthening within a certain extent will decrease the pressure in calcaneocuboid joint with a flatfoot deformity. Clinical Relevance: Performing the procedure with an 8 mm lengthening may reduce the risk of the secondary calcaneocuboid osteoarthritis.

Reconstruction of calcaneal fracture malunion with osteotomy and subtalar joint salvage: technique and outcomes.

Background: The goal of this study was to discuss the outcomes of treating calcaneal fracture malunion by restoring the subtalar joint with a reconstructive osteotomy. Methods: From May 2005 to November 2008, 24 patients (26 feet) with calcaneal malunions after a displaced intra-articular calcaneal fracture were treated by osteotomy and autogenous bone graft. The subtalar joint was preserved. The mean time from initial injury to reconstructive operation was 5.7 months (95% confidence interval, 4.5-8.8 months). The displaced posterior facet was restored through a reconstructive osteotomy, whereas the bone defect in the calcaneus after reduction was filled with the exostosis that had been removed; iliac bone graft was used if necessary. All patients were evaluated clinically and radiographically at a minimum of 24 months. Twenty patients (21 feet) were followed for a mean of 34.2 months (29.0-39.4 months). Results: According to American Orthopaedic Foot & Ankle Society (AOFAS) ankle and hindfoot score, the average score was 85.9 points (95% confidence interval, 81.5-90.4 points), which was significantly higher than the preoperative assessment. Radiographs showed that Böhler’s angle, Gissane’s angle, talus declination angle, and width and height of calcaneus were improved to a great extent. Six patients had wound edge necrosis, and 2 had superficial infection. One patient required a subtalar fusion for subtalar arthritis at 2 years after surgery. Conclusions: Restoring the subtalar joint with a reconstructive osteotomy and autogenous bone graft was an effective treatment method for selected calcaneal fracture malunions. It reconstructed calcaneal morphology and preserved the subtalar joint. Level of Evidence: Level IV, retrospective case series.

Fusion of Talonavicular and Naviculocuneiform Joints for the Treatment of Müller-Weiss Disease

Müller-Weiss disease is a rare spontaneous osteonecrosis of the tarsal and navicular bones in adults. From April 2008 to April 2011, we treated 7 patients with Müller-Weiss disease by surgical fusion of the talonavicular and naviculocuneiform joints with tricortical autologous iliac crest block fixated by screws and plate. Preoperative and postoperative clinical outcomes were evaluated with the American Orthopaedic Foot and Ankle Society ankle-hindfoot scale. The median follow-up time was 22 (range 3 to 38) months. All of the operated feet fused solidly. The median time for solid fusion was 13 (range 12 to 16) weeks. The median American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 49 (range 15 to 66) points preoperatively to 82 (range 68 to 87) points at last follow-up. The results suggest that this type of fusion is an effective surgical treatment for Müller-Weiss disease.

Treatment of displaced intraarticular calcaneal fractures with or without bone grafts: A systematic review of the literature

Background: The necessity of bone grafts in the treatment of intraarticular calcaneal fractures continues to be one of the most debated topics in foot and ankle surgery. The purpose of this study was to determine whether there are sufficient objective cumulative data in the literature to compare the two methods and if the bone graft was needed in surgical treatment of intraarticular calcaneal fractures. Materials and Methods: A comprehensive search of all relevant articles from 1990 to 2010 was conducted. Two reviewers evaluated each study to determine its suitability for inclusion and collected the data of interest. Meta-analytic pooling of group results across studies was performed for the two treatment methods. Results: The systematic review identified 32 primary studies with 1281 fractures, which contained 4 comparative studies, 13 with bone grafts, and 15 without bone grafts in treatment methods. The infection rate in bone graft group was higher through statistically insignificant than in non-graft group (8.3% vs. 6.3%) No significant difference was found between good reduction rate, postoperative osteoarthritis rate, and subtalar fusion rate. The average full weight-bearing time in bone graft group was significantly lower (5.4 months) than in non-graft group (10.5 months). The mean postoperative Böhlers angle was significantly higher in bone graft group (lose due to collapse was significancy less). For the efficacy outcomes, the bone graft group had a lower American Orthopaedic Foot and Ankle Society Score (AOFAS) (71.4 points vs. 80.5 points) but a higher Creighton score (89.9 points vs. 81.0 points) compared with non-graft group. Pooled mean results showed 35% of the patients in bone graft group had an excellent result, 40% had a good result, 21% had a fair result, and 4% had a poor result. In the non-graft group, the corresponding values were 34, 42, 14, and 10%, respectively. Conclusions: The operative treatment of intraarticular calcaneal fractures with bone grafts could restore the Böhlers angle better and the patients could return to full weight bearing earlier. However, the functional and efficacy outcomes appear to be similar between the two treatment groups. There were more joint depression and comminuted fractures in the bone graft group, and the mean followup time was shorter. Large sample comparative studies are still needed.

Anatomy and biomechanical properties of the plantar aponeurosis: a cadaveric study.

Objectives To explore the anatomy of the plantar aponeurosis (PA) and its biomechanical effects on the first metatarsophalangeal (MTP) joint and foot arch. Methods Anatomic parameters (length, width and thickness of each central PA bundle and the main body of the central part) were measured in 8 cadaveric specimens. The ratios of the length and width of each bundle to the length and width of the central part were used to describe these bundles. Six cadaveric specimens were used to measure the range of motion of the first MTP joint before and after releasing the first bundle of the PA. Another 6 specimens were used to evaluate simulated static weight-bearing. Changes in foot arch height and plantar pressure were measured before and after dividing the first bundle. Results The average width and thickness of the origin of the central part at the calcaneal tubercle were 15.45 mm and 2.79 mm respectively. The ratio of the length of each bundle to the length of the central part was (from medial to lateral) 0.29, 0.30, 0.28, 0.25, and 0.27, respectively. Similarly, the ratio of the widths was 0.26, 0.25, 0.23, 0.19 and 0.17. The thickness of each bundle at the bifurcation of the PA into bundles was (from medial to lateral) 1.26 mm, 1.04 mm, 0.91 mm, 0.84 mm and 0.72 mm. The average dorsiflexion of the first MTP joint increased 10.16° after the first bundle was divided. Marked acute changes in the foot arch height and the plantar pressure were not observed after division. Conclusions The first PA bundle was not the longest, widest, or the thickest bundle. Releasing the first bundle increased the range of motion of the first MTP joint, but did not acutely change foot arch height or plantar pressure during static load testing.

Exploração operatória e redução de sindesmose em lesão de tornozelo de Weber tipo C

OBJECTIVE: To investigate the surgical methods in treating Weber type C ankle injury and estimate the necessity of syndesmosis operative exploration. METHODS: Forty three patients of Weber type C ankle injury were treated with open reduction and internal fixation from October 2004 to December 2009. Twenty nine patients were treated with routine procedure by open reduction and internal fixation, syndesmosis exploration and repair were performed in addition in the others. Thirty four patients were followed during an average time of 31.2 months (range 18 to 50 months), amomg them 22 patients were treated with routine procedures and 12 were treated with additional syndesmosis surgical exploration. RESULTS: All the fractures were reunited in an average time of 13.1 weeks (range 10 to 18 weeks) and full weight bearing began. The mean ankle and hindfoot scale of the American Orthopaedic Foot and Ankle Society (AOFAS) score was 79.86(range 65 to 98) in the routine procedures group and 86.67 (range 78 to 100) in the syndesmosis exploration group and Olerud-Molander score was 77.27 (range 55 to 100) and 86.67 (range 75 to 100) respectively. Statistically significant difference was found between the two groups (P<0.05). CONCLUSION: Syndesmosis surgical exploration is an essential treatment in some Weber type C ankle injuries, which make debridement and direct reduction of the syndesmosis possible, providing thus a more stabilized ankle joint. Level of Evidence III, Retrospective Comparative Study

Experimental modeling and biomechanical measurement of flatfoot deformity

Treatment of the flatfoot requires a quantitative understanding of the biomechanical factor on this common deformity. Seven unembalmed foot-ankle complex specimens were used in this study to model experimental flatfoot deformity by release of plantar fascia, spring ligament, long and short plantar ligaments. Digital speckle correlation method (DSCM) and strain gauges were applied to measure displacements and strains of specimens before and after ligaments resection. Acquired data were compared with each other and statistically analyzed. Results of this experiment showed different appearance of foot-arch according to release of different ligament or complex. Obvious flatfoot deformity appeared only after at least three of the four main ligaments were cut off. Under the condition that four ligaments were completely released, the arch height decreased, longitudinal arch prolonged, forefoot abduced, force in various tissues redistributed, and center of bearing shifted forwards. This method is suitable for constructing experimental model of flatfoot deformity. This study accumulated large amounts of data for further research.

Open reduction and internal fixation of posterior pilon fractures with buttress plate

Objective: Posterior pilon fractures are rare injuries and have not yet gained well recognition. The purpose of this study was to present the treatment outcome for patients with posterior pilon fractures treated with buttress plate. Method: In this retrospective study we identified patients with posterior pilon fractures of the distal tibia who had undergone open reduction and internal fixation at our institute. Between January 2007 and December 2009, 10 patients (mean age, 46.5 years) who had undergone buttress plating via either a posterolateral approach or a dual posterolateral-posteromedial approach, were selected. All 10 patients were available for follow-up. The clinical outcome was evaluated with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analogue scale (VAS). The radiological evaluation was performed using the osteoarthritis-score (OA-score). Results: Satisfactory reduction and stable fixation were accomplished in all patients. At a mean follow-up of 36.2 months, all patients had good radiological results and showed satisfactory clinical recovery. The mean AOFAS sore was 87.8, the mean OA-score was 0.6, and the mean VAS scores during rest, active motion, and weight-bearing walking were 0.6, 0.8, and 1.4, respectively. Conclusion: Buttress plating for posterior pilon fractures gave satisfactory clinical outcomes. It also ensured rigid fixation which in turn enabled earlier postoperative mobilization. Level of Evidence IV, Retrospective Study.