High rate of complications after corrective midfoot/subtalar arthrodesis and Achilles tendon lengthening in Charcot arthropathy type Sanders 2 and 3.

PURPOSE: Corrective midfoot resection arthrodesis is the standard treatment of Charcot arthropathy type Sanders 2 and 3 with severe dislocation. In order to critically evaluate the effect of surgical correction, a retrospective analysis of our patient cohort was performed. Hereby, special emphasis was set on the analysis of the pre- and post-operative equinus position of the hindfoot. METHODS: Retrospectively, all patients (n = 82) after midfoot resection arthrodesis in Charcot type Sanders 2 or 3 were included. Complications were recorded, and the mean complication-free interval was calculated. Additionally, the calcaneal pitch as well as Meary's angle were measured pre- and post-operatively and in case of complications. RESULTS: Overall complication rate was 89%. Revision surgery was necessary in 46% of all patients. The mean complication-free interval was 285 days (0-1560 days). Calcaneal pitch and Meary's angle significantly improved after operation but returned to pre-operative values after onset of complications. Achilles tendon lengthening showed no significant effects on the mean complication-free interval. CONCLUSION: Operative treatment of Charcot arthropathy remains a surgical challenge with high complication rates. Surgical correction of equinus position has been highlighted for successful treatment but was not able to prevent complications in this study, which is demonstrated by the recurrent decrease of the calcaneal pitch in cases of reoperation. Therefore, as a conclusion of our results, our treatment algorithm changed towards primarily addressing the equinus malpositioning of the hindfoot by corrective arthrodesis of the hindfoot.

[Surgical treatment of distal triceps tendon ruptures]. / Operative Therapie der distalen Trizepssehnenruptur.

OBJECTIVE: Restoration of the anatomy and the original length of the muscle-tendon unit in triceps tendon ruptures. INDICATIONS: Acute and chronic triceps tendon ruptures with persisting symptoms and significant strength deficits. CONTRAINDICATIONS: Infections and tumors in the surgical area. SURGICAL TECHNIQUE: Prone position. Skin incision over the distal triceps in a lateral direction around the olecranon. Mobilization of the tendon and débridement of the olecranon. Drilling of 2â€¯× 2.9 mm suture anchor holes medial and lateral into the footprint of the olecranon. In addition, drilling through the olecranon 12 mm distal to the tip of the olecranon and transosseous introduction of 4 sutures. Then the suture anchors (all-suture or titanium anchors) are inserted into the drill holes. Refix the deep and superficial tendons with the anchor threads. Refix the upper tendon portions with the transosseous sutures. In the case of chronic lesions, a graft interposition is necessary. POSTOPERATIVE MANAGEMENT: Dorsal 10 ° splint, then change to an orthosis fixed in 20 ° extension and passive mobility 0-30 ° flexion for 6 weeks. From the 7th week onwards, load-free, physiotherapeutically controlled increasing mobilization. Starting weight-loading from the 13th week on. Full load after 6 months. RESULTS: In all, 34 male strength athletes with acute triceps tendon rupture underwent surgery using the hybrid technique described and were prospectively recorded. The MEPS­G score averaged 94.7 points, there were no permanent limitations in mobility, and the postoperative strength ability averaged 94% of the original strength performance ability. The return to sport achieved 100%. The complication rate was 20.6%. Reconstruction of the distal triceps tendon using hybrid technology leads to very good functional results. Half of all patients complained of symptoms even before the rupture, which suggests previous damage to the distal triceps tendon caused by degeneration.

Evidence-Based Surgical Treatment Algorithm for Unstable Syndesmotic Injuries.

BACKGROUND: Surgical treatment of unstable syndesmotic injuries is not trivial, and there are no generally accepted treatment guidelines. The most common controversies regarding surgical treatment are related to screw fixation versus dynamic fixation, the use of reduction clamps, open versus closed reduction, and the role of the posterior malleolus and of the anterior inferior tibiofibular ligament (AITFL). Our aim was to draw important conclusions from the pertinent literature concerning surgical treatment of unstable syndesmotic injuries, to transform these conclusions into surgical principles supported by the literature, and finally to fuse these principles into an evidence-based surgical treatment algorithm. METHODS: PubMed, Embase, Google Scholar, The Cochrane Database of Systematic Reviews, and the reference lists of systematic reviews of relevant studies dealing with the surgical treatment of unstable syndesmotic injuries were searched independently by two reviewers using specific terms and limits. Surgical principles supported by the literature were fused into an evidence-based surgical treatment algorithm. RESULTS: A total of 171 articles were included for further considerations. Among them, 47 articles concerned syndesmotic screw fixation and 41 flexible dynamic fixations of the syndesmosis. Twenty-five studies compared screw fixation with dynamic fixations, and seven out of these comparisons were randomized controlled trials. Nineteen articles addressed the posterior malleolus, 14 the role of the AITFL, and eight the use of reduction clamps. Anatomic reduction is crucial to prevent posttraumatic osteoarthritis. Therefore, flexible dynamic stabilization techniques should be preferred whenever possible. An unstable AITFL should be repaired and augmented, as it represents an important stabilizer of external rotation of the distal fibula. CONCLUSIONS: The current literature provides sufficient arguments for the development of an evidence-based surgical treatment algorithm for unstable syndesmotic injuries.

Tape suture for stabilization of incomplete posterior pelvic ring fractures-biomechanical analysis of a new minimally invasive treatment for incomplete lateral compression pelvic ring fractures.

BACKGROUND: Incomplete lateral compression fractures (including AO Type B2.1) are among the most common pelvic ring injuries. Although the treatment of choice remains controversial, sacroiliac (SI) screws are commonly used for the operative treatment of incomplete lateral compression fractures of the pelvic ring. However, the disadvantages of SI screws include the risk of nerve root or blood vessel injury. Recently, tape sutures have been found useful as stabilizing material for the treatment of injuries of the syndesmosis, the rotator cuff and knee ligaments. In this current study, we aimed to test the biomechanical feasibility of tape sutures to stabilize the pelvis in the setting of AO Type B2.1 injury. METHODS: Six human cadaveric pelvises underwent cyclic loading to compare the biomechanical stability of different osteosynthesis methods in a B2.1 fracture model. The methods tested in this experiment were a FiberTape® suture and the currently established SI screw. A 3D ultrasound tracking system was used to measure fracture fragment motion. Linear regression was used to model displacement and stiffness at the posterior and anterior pelvic ring. RESULTS: At the posterior fracture site, the FiberTape® demonstrated similar displacement (2.2 ± 0.8 mm) and stiffness (52.2 ± 18.0 N/mm) compared to the sacroiliac screw (displacement 2.1 ± 0.6 mm, P >  0.999; stiffness 50.8 ± 13.0 N/mm, P > 0.999). Considering the anterior fracture site, the FiberTape® again demonstrated similar displacement (3.8 ± 1.3 mm) and stiffness (29.5 ± 9.0 N/mm) compared to the sacroiliac screw (displacement 2.9 ± 0.8 mm, P = 0.2196; stiffness 37.5 ± 11.5 N/mm, P = 0.0711). CONCLUSION: The newly presented osteosynthesis, the FiberTape®, shows promising results for the stabilization of the posterior pelvic ring in AO Type B2.1 lateral compression fractures compared to a sacroiliac screw osteosynthesis based on its minimal-invasiveness and the statistically similar biomechanical properties.

Syndesmotic InternalBraceTM for anatomic distal tibiofibular ligament augmentation.

Reconstruction of unstable syndesmotic injuries is not trivial, and there is no generally accepted treatment guidelines. Thus, there still remain considerable controversies regarding diagnosis, classification and treatment of syndesmotic injuries. Syndesmotic malreduction is the most common indication for early re-operation after ankle fracture surgery, and widening of the ankle mortise by only 1 mm decreases the contact area of the tibiotalar joint by 42%. Outcome of ankle fractures with syndesmosis injury is worse than without, even after surgical syndesmotic stabilization. This may be due to a high incidence of syndesmotic malreduction revealed by increasing postoperative computed tomography controls. Therefore, even open visualization of the syndesmosis during the reduction maneuver has been recommended. Thus, the most important clinical predictor of outcome is consistently reported as accuracy of anatomic reduction of the injured syndesmosis. In this context the TightRope® system is reported to have advantages compared to classical syndesmotic screws. However, rotational instability of the distal fibula cannot be safely limited by use of 1 or even 2 TightRopes®. Therefore, we developed a new syndesmotic InternalBraceTM technique for improved anatomic distal tibiofibular ligament augmentation to protect healing of the injured native ligaments. The InternalBraceTM technique was developed by Gordon Mackay from Scotland in 2012 using SwiveLocks® for knotless aperture fixation of a FiberTape® at the anatomic footprints of the augmented ligaments, and augmentation of the anterior talofibular ligament, the deltoid ligament, the spring ligament and the medial collateral ligaments of the knee have been published so far. According to the individual injury pattern, patients can either be treated by the new syndesmotic InternalBraceTM technique alone as a single anterior stabilization, or in combination with one posteriorly directed TightRope® as a double stabilization, or in combination with one TightRope® and a posterolateral malleolar screw fixation as a triple stabilization. Moreover, the syndesmotic InternalBraceTM technique is suitable for anatomic refixation of displaced bony avulsion fragments too small for screw fixation and for indirect reduction of small posterolateral tibial avulsion fragments by anatomic reduction of the anterior syndesmosis with an InternalBraceTM after osteosynthesis of the distal fibula. In this paper, comprehensively illustrated clinical examples show that anatomic reconstruction with rotational stabilization of the syndesmosis can be realized by use of our new syndesmotic InternalBraceTM technique. A clinical trial for evaluation of the functional outcomes has been started at our hospital.

Development of an internally braced prosthesis for total talus replacement.

Total loss of talus due to trauma or avascular necrosis, for example, still remains to be a major challenge in foot and ankle surgery with severely limited treatment options. Implantation of a custom made total talar prosthesis has shown promising results so far. Most important factors for long time success are degree of congruence of articular surfaces and ligamentous stability of the ankle. Therefore, our aim was to develop an optimized custom made prosthesis for total talus replacement providing a high level of primary stability. A custom made hemiprosthesis was developed using computed tomography and magnetic resonance imaging data of the affected and contralateral talus considering the principles and technology for the development of the S.T.A.R. prosthesis (Stryker). Additionally, four eyelets for fixation of artificial ligaments were added at the correspondent footprints of the most important ligaments. Two modifications can be provided according to the clinical requirements: A tri-articular hemiprosthesis or a bi-articular hemiprosthesis combined with the tibial component of the S.T.A.R. total ankle replacement system. A feasibility study was performed using a fresh frozen human cadaver. Maximum range of motion of the ankle was measured and ligamentous stability was evaluated by use of standard X-rays after application of varus, valgus or sagittal stress with 150 N. Correct implantation of the prosthesis was technically possible via an anterior approach to the ankle and using standard instruments. Malleolar osteotomies were not required. Maximum ankle dorsiflexion and plantarflexion were measured as 22-0-28 degrees. Maximum anterior displacement of the talus was 6 mm, maximum varus tilt 3 degrees and maximum valgus tilt 2 degrees. Application of an internally braced prosthesis for total talus replacement in humans is technically feasible and might be a reasonable procedure in carefully selected cases with no better alternatives left.

Diagnosis of Musculus Gastrocnemius Tightness - Key Factors for the Clinical Examination.

Common foot and ankle pathologies have been linked to isolated Musculus gastrocnemius tightness (MGT). Various examination techniques have been described to assess MGT. Still, a standardized examination procedure is missing. Literature argues for weightbearing examination but the degree of knee flexion needed to eliminate the restraining effect of the M. gastrocnemius on ankle dorsiflexion (ADF) is unknown. This manuscript investigates the effect of knee flexion on ankle dorsiflexion and provides a detailed description of a standardized examination protocol. Examination on 20 healthy individuals revealed, that 20° of knee flexion is sufficient to fully eliminate the influence of the M. gastrocnemius on ADF. This builds the prerequisite for a standardized examination for MGT. Non-weightbearing and weightbearing examination of ADF has to be conducted with the knee fully extended and at least 20° flexed. Two investigators should conduct non-weightbearing testing with the subject in supine position. In order to obtain reliable results, the axis of the fibula should be marked. One examiner can conduct weightbearing examination with the subject in lunge stance. Isolated MGT is present if ADF is impaired with the knee fully extended and knee flexion results in a significant ADF increase. The herein presented standardized examination is the prerequisite for future studies aiming at establishing norm values.

The value of arthroscopy in the treatment of complex ankle fractures - a protocol of a randomised controlled trial.

BACKGROUND: An anatomical reconstruction of the ankle congruity is the important prerequisite in the operative treatment of acute ankle fractures. Despite anatomic restoration patients regularly suffer from residual symptoms after these fractures. There is growing evidence, that a poor outcome is related to the concomitant traumatic intra-articular pathology. By supplementary ankle arthroscopy anatomic reduction can be confirmed and associated intra-articular injuries can be treated. Nevertheless, the vast majority of complex ankle fractures are managed by open reduction and internal fixation (ORIF) only. Up to now, the effectiveness of arthroscopically assisted fracture treatment (AORIF) has not been conclusively determined. Therefore, a prospective randomised study is needed to sufficiently evaluate the effect of AORIF compared to ORIF in complex ankle fractures. METHODS/DESIGN: We perform a randomised controlled trial at Munich University Clinic enrolling patients (18-65 years) with an acute ankle fracture (AO 44 A2, A3, B2, B3, C1 - C3 according to AO classification system). Patients meeting the inclusion criteria are randomised to either intervention group (AORIF, n = 37) or comparison group (ORIF, n = 37). Exclusion criteria are fractures classified as AO type 44 A1 or B1, pilon or plafond-variant injury or open fractures. Primary outcome is the AOFAS Score (American Orthopaedic Foot and Ankle Society). Secondary outcome parameter are JSSF Score (Japanese Society of Surgery of the Foot), Olerud and Molander Score, Karlsson Score, Tegner Activity Scale, SF-12, radiographic analysis, arthroscopic findings of intra-articular lesions, functional assessments, time to return to work/sports and complications. This study protocol is accordant to the SPIRIT 2013 recommendation. Statistical analysis will be performed using SPSS 22.0 (IBM). DISCUSSION: The subjective and functional outcome of complex ankle fractures is regularly unsatisfying. As these injuries are very common it is essential to improve the postoperative results. Potentially, arthroscopically assisted fracture treatment can significantly improve the outcome by addressing the intra-articular pathologies. Given the absolute lack of studies comparing AORIF to ORIF in complex ankle fractures, this randomised controlled trail is urgently needed to evaluate the effectiveness of additional arthroscopy. TRIAL REGISTRATION: ClinicalTrials.gov reference: NCT02449096 (Trial registration date: April 7th, 2015).

The influence of knee position on ankle dorsiflexion - a biometric study.

BACKGROUND: Musculus gastrocnemius tightness (MGT) can be diagnosed by comparing ankle dorsiflexion (ADF) with the knee extended and flexed. Although various measurement techniques exist, the degree of knee flexion needed to eliminate the effect of the gastrocnemius on ADF is still unknown. The aim of this study was to identify the minimal degree of knee flexion required to eliminate the restricting effect of the musculus gastrocnemius on ADF. METHODS: Bilateral ADF of 20 asymptomatic volunteers aged 18-40 years (50% female) was assessed prospectively at six different degrees of knee flexion (0°, 20°, 30°, 45°, 60°, 75°, Lunge). Tests were performed following a standardized protocol, non weightbearing and weightbearing, by two observers. Statistics comprised of descriptive statistics, t-tests, repeated measurement ANOVA and ICC. RESULTS: 20 individuals with a mean age of 27 ± 4 years were tested. No significant side to side differences were observed. The average ADF [95% confidence interval] for non weightbearing was 4° [1°-8°] with the knee extended and 20° [16°-24°] for the knee 75° flexed. Mean weightbearing ADF was 25° [22°-28°] for the knee extended and 39° [36°-42°] for the knee 75° flexed. The mean differences between 20° knee flexion and full extension were 15° [12°-18°] non weightbearing and 13° [11°-16°] weightbearing. Significant differences of ADF were only found between full extension and 20° of knee flexion. Further knee flexion did not increase ADF. CONCLUSION: Knee flexion of 20° fully eliminates the ADF restraining effect of the gastrocnemius. This knowledge is essential to design a standardized clinical examination assessing MGT.

Hallux rigidus: Joint preserving alternatives to arthrodesis - a review of the literature.

Hallux rigidus describes the osteoarthritis of the first metatarsophalangeal joint. It was first mentioned in 1887. Since then a multitude of terms have been introduced referring to the same disease. The main complaints are pain especially during movement and a limited range of motion. Radiographically the typical signs of osteoarthritis can be observed starting at the dorsal portion of the joint. Numerous classifications make the comparison of the different studies difficult. If non-operative treatment fails to resolve the symptoms operative treatment is indicated. The most studied procedure with reproducible results is the arthrodesis. Nevertheless, many patients refuse this treatment option, favouring a procedure preserving motion. Different motion preserving and joint sacrificing operations such as arthroplasty are available. In this review we focus on motion and joint preserving procedures. Numerous joint preserving osteotomies have been described. Most of them try to relocate the viable plantar cartilage more dorsally, to decompress the joint and to increase dorsiflexion of the first metatarsal bone. Multiple studies are available investigating these procedures. Most of them suffer from low quality, short follow up and small patient numbers. Consequently the grade of recommendation is low. Nonetheless, joint preserving procedures are appealing because if they fail to relief the symptoms an arthrodesis or arthroplasty can still be performed thereafter.

Neurovascular complications due to the Hippocrates method for reducing anterior shoulder dislocations.

In spite of the fact that the Hippocrates method hardly has been evaluated in a scientific manner and numerous associated iatrogenic complications have been reported, this method remains to be one of the most common techniques for reducing anterior shoulder dislocations. We report the case of a 69-year-old farmer under coumarin anticoagulant therapy who sustained acute first time anterior dislocation of his dominant right shoulder. By using the Hippocrates method with the patient under general anaesthesia, the brachial vein was injured and an increasing hematoma subsequently caused brachial plexus paresis by pressure. After surgery for decompression and vascular suturing, symptoms declined rapidly, but brachial plexus paresis still was not fully reversible after 3 mo of follow-up. The hazardousness of using the Hippocrates method can be explained by traction on the outstretched arm with force of the operator's body weight, direct trauma to the axillary region by the physician's heel, and the topographic relations of neurovascular structures and the dislocated humeral head. As there is a variety of alternative reduction techniques which have been evaluated scientifically and proofed to be safe, we strongly caution against the use of the Hippocrates method as a first line technique for reducing anterior shoulder dislocations, especially in elder patients with fragile vessels or under anticoagulant therapy, and recommend the scapular manipulation technique or the Milch technique, for example, as a first choice.

Study protocol: the effect of whole body vibration on acute unilateral unstable lateral ankle sprain- a biphasic randomized controlled trial.

BACKGROUND: Ankle sprains often result in ankle instability, which is most likely caused by damage to passive structures and neuromuscular impairment. Whole body vibration (WBV) is a neuromuscular training method improving those impaired neurologic parameters. The aim of this study is to compare the current gold standard functional treatment to functional treatment plus WBV in patients with acute unilateral unstable inversion ankle sprains. METHODS/DESIGN: 60 patients, aged 18-40 years, presenting with an isolated, unilateral, acute unstable inversion ankle sprain will be included in this bicentric, biphasic, randomized controlled trial. Samples will be randomized by envelope drawing. All patients will be allowed early mobilization and pain-dependent weight bearing, limited functional immobilization by orthosis, PRICE, NSARDs as well as home and supervised physiotherapy. Supervised physical therapy will take place twice a week, for 30 minutes for a period of 6 weeks, following a standardized intervention protocol. During supervised physical therapy, the intervention group will perform exercises similar to those of the control group, on a side-alternating sinusoidal vibration platform. Two time-dependent primary outcome parameters will be assessed: short-term outcome after six weeks will be postural control quantified by the sway index; mid-term outcome after one year will be assessed by subjective instability, defined by the presence of giving-way attacks. Secondary outcome parameters include: return to pre-injury level of activities, residual pain, recurrence, objective instability, energy/coordination, Foot and Ankle Disability Index and EQ 5D. DISCUSSION: This is the first trial investigating the effects of WBV in patients with acute soft tissue injury. Inversion ankle sprains often result in ankle instability, which is most likely due to damage of neurological structures. Due to its unique, frequency dependent, influence on various neuromuscular parameters, WBV is a promising treatment method for patients with acute unstable inversion ankle sprains. TRIAL REGISTRATION: NCT01702597.

Flexible intramedullary nailing of a displaced transverse sternal fracture associated with a flexion-compression injury of the thoracic spine.

STUDY DESIGN: A case report. OBJECTIVE: To report the successful surgical management of a patient with a displaced sternal fracture associated with flexion-compression injury to the thoracic spine by flexible intramedullary nailing of the sternum, thereby emphasizing the existence and clinical relevance of the concept of the fourth column of the thoracic spine. SUMMARY OF BACKGROUND DATA: Displaced sternal fractures resulting from indirect trauma are often associated with unstable injuries to the thoracic spine that require stabilization of the spine to prevent increasing kyphosis. The theory of the sternal-rib-complex as a possible fourth column giving structural support to the thoracic spine has been proposed. However, such a model has rarely been described, and the role of surgical stabilization of an unstable fourth column is unknown. METHODS: A 58-year-old man with Forestier syndrome presented with a severely displaced sternal fracture associated with an unstable injury to the thoracic spine at T4-T8 after a fall at ground level. The patient complained of sternal pain and respiratory distress. However, neurologically he was completely normal. His pain and respiratory distress improved, so he refused spinal stabilization, and was discharged 20 days after the injury. RESULTS: Eight weeks after the injury the patient complained of persistent sternal pain and symptoms of sternal instability. A computed tomogram (CT) showed increasing displacement of the sternal fracture and increasing kyphosis of the thoracic spine. To relieve the sternal pain and prevent further displacement the patient now agreed to stabilization of the sternal fracture by minimal invasive flexible intramedullary nailing. Postoperative CT showed an almost anatomically-reduced sternum and even a slight correction of the thoracic kyphosis. After removal of the implants 5 months later the patient was free of pain, and was able to resume normal physical activity and return to his work as a farmer. Thirty months after sternal stabilization surgery, CT showed complete healing of the sternal fracture and a continuing reduction of the thoracic kyphosis. CONCLUSION: This case supports the concept of the existence and clinical relevance of the fourth column of the thoracic spine, and its role in giving added spinal stability.

Quantitative scanning acoustic microscopy compared to microradiography for assessment of new bone formation.

Recently, it has been shown that quantitative scanning acoustic microscopy (SAM) is a powerful tool to image the acoustic impedance of even inhomogeneous materials like bone. Therefore, the aim of our study was to compare SAM to conventional microradiography with respect to histomorphometrical assessment of undecalcified sections of newly formed bone. Forty specimens were harvested 12 weeks after implantation of either autogenous cancellous bone graft or 5.0 mg of Osteogenic Protein-1 (BMP-7) in a critical-sized defect model in sheep. Undecalcified transverse bone sections of 500 microm thickness were investigated with conventional microradiography and SAM. Linear regression analysis was carried out to compare the measurements of the area of new bone formation within the defect sites. Both methods allowed for good discrimination between newly formed bone and cortical bone at the edges of the former defect. Images obtained with SAM revealed a better resolution and sharpness compared to that of microradiographs since SAM imaging unlike microradiography does not depend on the thickness of bone sections. The results of quantitative histomorphometric analysis obtained by both methods showed no significant differences, and it was possible to predict 90% of the variability of each method (coefficient of determination r2 = 0.90; P < 0.0001). In conclusion, SAM offers comparable quantitative histomorphometric information with a better spatial resolution than conventional microradiography. Thus, SAM is a promising new micro-visualizing technique for basic bone research.

Closed reduction of forearm refractures with flexible intramedullary nails in situ.

BACKGROUND: Refractures of the forearm after flexible intramedullary nailing are rare. An alternative to nail replacement is closed reduction with the nails in situ. We successfully performed this maneuver on a thirteen-year-old boy. However, no data on the stability of previously bent nails are available. The purpose of the present study was to assess the mechanical stability of titanium and stainless steel flexible intramedullary nails after one cycle of reversed bending. METHODS: In an in vitro study, ten titanium and eighteen stainless steel 3.0-mm flexible intramedullary nails were subjected to an increasing lateral bending force until the point of first plastic deformation. As an analogy to the clinical case, they were then bent to an angle of 21 degrees and were manually reduced back to their original straight position and the experiment was repeated. The forces needed to achieve first plastic deformation and modified spring constants (force/deflection) were calculated and were compared between the native and previously bent nails. RESULTS: The average force required for permanent deformation of the previously bent nails was reduced by 37% for both titanium and stainless steel nails (from 21 to 13.2 N for titanium nails [p < 0.01] and from 25 to 15.7 N for stainless steel nails [p < 0.001]). The average modified spring constant decreased by 15.1% (from 0.814 to 0.691 N/ degrees ) for titanium nails (p < 0.001) and by 12.2% (from 0.991 to 0.870 N/ degrees ) for stainless steel nails (p < 0.001). Overall, steel nails were stiffer and stronger than titanium nails were. There was no macroscopic evidence of metal fracture or fatigue after one cycle of reversed bending to 21 degrees. CONCLUSIONS: Closed reduction of a forearm refracture with flexible intramedullary nails in situ is a safe, noninvasive, and effective alternative to nail replacement. However, mechanical stability of the nails is significantly reduced after the procedure. Therefore, the patient should be instructed to avoid any excessive forces to the forearm until fracture union has been documented radiographically, and casting for a limited time may be appropriate.