Evaluation of fixation techniques with titanium plates and Kirschner wires for zygoma fractures: preliminary study.

OBJECTIVE: The aim of the present study was to assess the quality of treatment using two reduction and fixation techniques for zygoma fractures. PATIENTS AND METHODS: A randomized clinical trial was carried out involving a sample of 10 patients with Knight and North type III, IV and V zygoma fractures divided into two groups. One group underwent the closed reduction technique and fixation with Kirschner wire and the other group underwent the open reduction technique and fixation with titanium plates. The groups were submitted to subjective evaluation based on the patient's perception of areas of deformity and paresthesia as well as the measurement of range of mouth opening and pain upon mouth opening in the preoperative (T0) and postoperative (T1) periods. The assessment of bone reduction quality was performed using quantifiable points (lateral wall of the orbit, anteroposterior projection of the zygoma and ocular globe projection), measured based on tomographic images. RESULTS: Seventy percent of the patients remained with paresthesia and 20% remained with the complaint of deformity at T1. Mouth opening range increased in both groups at T1. In the overall sample, mean total disjunction of the lateral wall of the orbit and the difference in the anteroposterior projection of the zygoma were reduced between T0 and T1 (4.36 mm to 1.25 mm and 6.94 mm to 2.86 mm, respectively). There was also a reduction in ocular globe projection in both groups between T0 and T1. CONCLUSIONS: Both techniques achieved adequate reduction of zygoma fractures in the postoperative period.

Less-invasive stabilization of rib fractures by intramedullary fixation: a biomechanical evaluation.

BACKGROUND: This study evaluated intramedullary fixation of rib fractures with Kirschner wires and novel ribs splints. We hypothesized that rib splints can provide equivalent fixation strength while avoiding complications associated with Kirschner wires, namely wire migration and cutout. METHODS: The durability, strength, and failure modes of rib fracture fixation with Kirschner wires and rib splints were evaluated in 22 paired human ribs. First, intact ribs were loaded to failure to determine their strength. After fracture fixation with Kirschner wires and rib splints, fixation constructs were dynamically loaded to 360,000 cycles at five times the respiratory load to determine their durability. Finally, constructs were loaded to failure to determine residual strength and failure modes. RESULTS: All constructs sustained dynamic loading without failure. Dynamic loading caused three times more subsidence in Kirschner wire constructs (1.2 mm +/- 1.4 mm) than in rib splint constructs (0.4 mm +/- 0.2 mm, p = 0.09). After dynamic loading, rib splint constructs remained 48% stronger than Kirschner wire constructs (p = 0.001). Five of 11 Kirschner wire constructs failed catastrophically by cutting through the medial cortex, leading to complete loss of stability and wire migration through the lateral cortex. The remaining six constructs failed by wire bending. Rib splint constructs failed by development of fracture lines along the superior and interior cortices. No splint construct failed catastrophically, and all splint constructs retained functional reduction and fixation. CONCLUSIONS: Because of their superior strength and absence of catastrophic failure mode, rib splints can serve as an attractive alternative to Kirschner wires for intramedullary stabilization of rib fractures, especially in the case of posterior rib fractures where access for plating is limited.

In vitro biomechanical evaluation and comparison of FiberWire, FiberTape, OrthoFiber, and nylon leader line for potential use during extraarticular stabilization of canine cruciate deficient stifles.

OBJECTIVE: To compare biomechanical properties of 3 new generation polyethylene sutures (FiberTape [FT], FiberWire [FW], and OrthoFiber [OF]) with nylon leader line (NL) for use during extraarticular fixation of cranial cruciate deficient stifles. STUDY DESIGN: In vitro biomechanical testing of suture loops under monotonic tensile and cyclical loading until failure. SAMPLE POPULATION: Constructs of FT, FW, OF, and NL. METHODS: Twenty loops of each of 12 combinations of fixation and suture had monotonic tensile and cyclical loading. Two knotting techniques (square knot [SQ], slip knot [SL]) and a crimp clamp (CR) system were evaluated. Elongation, stiffness, and strength of constructs was tested. The main effects of group, loop material, and their interaction were evaluated. RESULTS: Knotted FT, FW, and OF had less elongation than knotted NL under monotonic tensile and cyclical loading. Under monotonic tensile loading, knotted FT and OF were stiffer than knotted NL. CR FT, CR FW, and CR OF were stiffer than CR NL and CR FT, CR FW, and CR OF were stiffer than knotted FT, FW, and OF. FW and OF knotted loops were weaker than knotted NL. CR FT was stronger than CR NL. CR FT and CR OF were weaker than knotted FT and OF. CONCLUSIONS: Polyethylene sutures are stronger, stiffer and elongate less than nylon leader. Crimping suture alters the biomechanical properties of the loop. CLINICAL RELEVANCE: FW, FT, and OF may perform better in reconstructive procedures, where increased strength and stiffness are considered to be beneficial.

[Clinical application of nitinol memory alloy two foot fixator combined with Kirschner wire in treatment of trans-scaphoid perilunate dislocation].

OBJECTIVE: To evaluate the effectiveness of nitinol memory alloy two foot fixator combined with Kirschner wire in the treatment of trans-scaphoid perilunate dislocation. METHODS: Between September 2011 and October 2018, 17 patients with trans-scaphoid perilunate dislocation were treated with nitinol memory alloy two foot fixator and Kirschner wire. There were 12 males and 5 females, with an average age of 32.6 years (range, 23-52 years). The disease duration was 8 hours to 9 days, with an average of 6.5 days. The causes of injury included 6 cases of falling injury, 4 cases of traffic accident injury, 3 cases of stress injury of wrist caused by sports, 2 cases of violent injury of wrist caused by machine impact, 1 case of military training injury, and 1 case of other injury. One case was complicated with nerve injury. According to Herbert's classification, all the fractures were type B4. At 1 week before operation, 3 months, 6 months after operation and last follow-up, the wrist function was evaluated according to the Krimmer scale score. RESULTS: All the 17 patients were followed up 10.5-48 months, with an average of 18.6 months. There was no loosening or infection of the internal fixator, no necrosis of the scaphoid and lunate. The periosteal dislocations of the patients were well reduced and the scaphoid fractures all healed. The healing time was 4-18 months, with an average of 11.3 months. The Krimmer wrist scores were 37.5±4.4, 61.3±7.2, 83.3±9.3, 87.3±8.2 at 1 week before operation, 3 months, 6 months after operation and last follow-up, respectively. The Krimmer wrist score at each time point after operation was significantly improved when compared with that before operation ( P<0.05), and at 6 months after operation and last follow-up than at 3 months after operation ( P<0.05). There was no significant difference between at 6 months and last follow-up ( P>0.05). At last follow-up, the Krimmer wrist function was excellent in 13 cases, good in 2 cases, fair in 1 case, poor in 1 case, and the excellent and good rate was 88.23%. CONCLUSION: Nitinol memory alloy two foot fixator combined with Kirschner wire in the treatment of trans-scaphoid periosteal dislocation has definite effectiveness, simple operation, and good recovery of wrist function after operation.

Modified tension band wiring of patellar fracture as a technique to minimize postoperative complications: A case report.

RATIONALE: Tension band wiring is the most widely accepted technique for the treatment of patellar fractures but the technique is associated with common complications like wire migration, prominence, and breakage. To reduce these complications, we developed and propose a modified technique that has a superior biomechanical strength and a potential to reduce such postoperative complications. PATIENT CONCERNS: The patient presented with pain and mild swelling in his left knee after he slipped on the floor and fell on his left knee. He has no significant past medical or surgical history. The patient took the tension band wiring as the first choice because of the wide acceptance. But he worried about the complications. DIAGNOSES: X-ray showed a transverse fracture of the left patella with an inferior pole occult fracture. INTERVENTIONS: The patient was operated with a modified technique of the classic tension band wiring for patellar fractures. In our 4-step procedure, double tension cerclage wires were wrapped under the exposed ends of the Kirschner wires (K-wires) and the tendons in figure-of-8 fashion. The aim was to increase the biomechanical strength so that when one of the tension wires fail, the other one can hold the fragments together. OUTCOMES: The patient recovered very well and without any complications. The patient was followed-up for 1 year and the fracture has united very well, with satisfying knee range of motion. LESSONS: From this case study, we can detect the biomechanical advantages of our technique which can increase the stability of the fracture and that allows early functional exercise and additionally the micromotion at the fracture site has a beneficial effect of fracture union. Based on the perfect outcomes, our technique is worthy of clinical application.

Kirner's deformity of the fifth finger: A case report.

RATIONALE: Kirner's deformity is an uncommon deformity of finger, characterized by palmo-radial curvature of distal phalanx of the fifth finger. The specific mechanism remains unknown yet. This study aims to present a case report to add the knowledge on this type of deformity. PATIENT CONCERNS: A 9-year-old girl presenting with deformity of her fifth finger since she was born was admitted to our hand surgery clinic. MRI findings showed widened epiphyseal plate, L-shaped physis, but normal flexor digitorum profundus tendon insertion, without any significantly enhanced soft issues. DIAGNOSIS: Kirner's deformity of the fifth finger. INTERVENTIONS: We presented 2 surgical choices for the patient: one was wedge osteotomy of the distal phalanx to correct the mechanical line of the distal phalanx and fixation with Kirschner wire and the other one was cut-off of deep flexor tendon insertion with brace immobilization, but her guardians refused either of them. OUTCOMES: Consecutive follow-up was performed for 19 months after the first visit, showing no any change in finger shape and function. LESSONS: The L-shaped epiphyses may be the cause of Kirner's deformity and further attention should be paid on in the clinic. This case report provided a basis for the etiological diagnosis and future treatment of Kirner's deformity.

Biomechanical comparison of bi- and tricortical k-wire fixation in tension band wiring osteosynthesis.

BACKGROUND: Patients with a simple transversal fracture of the olecranon are often treated with a tension band wiring (TBW), because it is known as a biomechanically appropriate and cost-effective procedure. Nevertheless, the technique is in detail more challenging than thought, resulting in a considerable high rate of implant-related complications like k-wire loosening and soft tissue irritation. In the literature, a distinction is generally only made between transcortical (bi-) and intramedullary (mono-) fixation of the wires. There is the additional possibility to fix the proximal bent end of k-wire in the cortex of the bone and thus create a tricortical fixation. The present study investigates the effectiveness of bi- and tricortical k-wire fixation in a biomechanical approach. METHODS: TBW of the olecranon was performed at 10 cadaver ulnas from six donors in a usual manner and divided into two groups: In group 1, the k-wire was inserted by bicortical fixation (BC), and in group 2, a tricortical fixation (TC) was chosen. Failure behavior and maximum pullout strength were assessed and evaluated by using a Zwick machine. The statistical evaluation was descriptive and with a paired t test for the evaluation of significances between the two techniques. RESULTS: The average age of the used donors was 81.5 ± 11.5 (62-92) years. Three donors were female, and three were male. Ten k-wires were examined in BC group and 10 in the TC group. The mean bone density of the used proximal ulnas was on average 579 ± 186 (336-899) HU. The maximum pullout strength was 263 ± 106 (125-429) N in the BC group and increased significantly in the TC group to 325 ± 102 (144-466) N [p = .005]. CONCLUSION: This study confirms for the first time biomechanical superiority of tricortical k-wire fixation in the olecranon when using a TBW and may justify the clinical use of this method.

Volar locking plate versus external fixation with optional additional K-wire for treatment of AO type C2/C3 fractures: a retrospective comparative study.

PURPOSE: This study aimed to compare the radiographic and functional results of Arbeitsgemeinschaftfür Osteosynthesefragen (AO) type C2/C3 fracture of distal radius between volar locking plate (VLP) and external fixation (EF). METHODS: It was a retrospective comparative study. Between January 2015 and March 2018, a total of 62/117 patients who underwent EF (23) or VLP fixation (39) for AO type C2/C3 distal radius fractures were assessed. The follow-up period was at least 12 months. Gartland-Werley scale and the disabilities of the arm, shoulder, and hand (DASH) scale were used to evaluate the overall functional outcomes; wrist range of motion and grip strength were measured. The radiographic parameters included radial inclination, volar tilt, radial length, ulnar variance, and articular step-off. All of the comparisons were performed using SPSS 21.0. RESULTS: The mean follow-up time was 17.1 months. At final visit, VLP performed better in wrist flexion (69.7° vs 62.3°, p < 0.001), forearm pronation (73.1° vs 64.8°, p = 0.027) and supination (70.6° vs 63.1°, p = 0.033) than EF, but not different with regard to other kinematic parameters. No significant difference was found between two groups, in term of Gartland-Werley or DASH score (p > 0.05). The ulnar variance and articular step-off was significantly more improved in VLP than EF group, being 0.6 vs 1.6 mm (p = 0.002) and 0.5 vs 1.2 mm (p = 0.007). The overall rate of complications did not differ in both groups (28.2% vs 34.5%) (p = 0.587). CONCLUSIONS: Compared to EF, VLP fixation showed better performance in wrist mobility, correction of ulnar variance, and improving articular congruence, but with the comparable overall functional outcomes and complication rate.

Shearing Osteochondral Fracture of the Humeral Head: A Case Report.

CASE: A 30-year-old man was found to have a posteriorly displaced osteochondral shear fracture of his left humeral head, likely from dislocation and relocation. The fragment was fixed in its native position using headless screws, and the patient regained full strength and range of motion within 9 months. CONCLUSIONS: Osteochondral shear fractures of the humeral head appear to shear off the anteromedial articular joint surface after dislocation and relocation. One should be suspicious for associated labral tears. Arthroplasty is a valid treatment option, but select patients may be eligible for other viable options.

Elastic fixation of mallet finger fractures using two K-wires: A case report of a new fixation technique.

RATIONALE: Mallet finger fracture is a common sports-related injury that may lead to the tearing of extensor tendon and protrusion of a bony fragment located at the base of the distal phalanx. We affirmed that the elastic fixation of with two K-wires technique is a good method to deal with Mallet Finger fractures that fractures could gain effective fixation than the conventional treatment method and avoid surgical incision complication PATIENT CONCERNS:: We reported a 33-year-old female patient came to our hospital complaining of mild pain, swelling and her right little finger was deformed because of sport's injury. DIAGNOSIS: Acute mallet finger fracture type IV B according to Doyle classification of mallet injuries. INTERVENTIONS: We performed an emergency operation for the elastic fixation of the mallet finger fractures with two K-wires. OUTCOMES: After the surgery, the patient showed functional recovery. No evidence of recurrence was noted 6 months after the operation, and the patient showed no symptoms of sports-related injuries. LESSONS: We discuss the clinical diagnosis, treatment, and follow-up of the patient and suggest that elastic fixation with two K-wires is a good method to treat mallet finger fractures.

An in vitro comparison of a 2.7/3.5 mm hybrid plate alone and combined with crossed K-wires for canine pancarpal arthrodesis.

Several techniques have been described for canine pancarpal arthrodesis (PCA) with dorsal plating becoming the most accepted method for ease of placement despite the proposed biomechanical disadvantages. The aim of this study was to compare the biomechanical effects of the addition of crossed K-wires to a standard 2.7/3.5 mm hybrid PCA plate. A 2.7/3.5 mm hybrid PCA plate, alone and combined with crossed K-wires were tested. Six pairs of cadaver forelimbs were collected from medium-sized dogs with an average weight of 24 kg by elbow disarticulation. The limbs were potted and fixed in an Instron load cell (Instron, High Wycombe, UK) and axially loaded to failure. Load displacement data and mode of failure were recorded and stiffness, yield load and ultimate load at failure were calculated. The yield load (kN) of the plate and K-wire construct (1.278+/-0.11) was significantly higher than for the plate construct alone (1.002+/-0.07) (p=0.00056). However, the differences between the two constructs in stiffness and failure loads were not significant.

Congenital pseudarthrosis of the clavicle treated by Masquelet technique.

Congenital pseudarthrosis of the clavicle (CPC) is a very rare pathology of which over 200 cases have been reported. Usually discovered during the first months of life, CPC is characterised by a definitive bone defect in the middle third of the clavicle. Generally asymptomatic, the pseudarthrosis of the clavicle can cause aesthetic issues and functional symptoms indicating a surgical repair. Different reconstruction techniques have been reported with various complications. We present a 14-year-old boy diagnosed with CPC and concerned about the cosmetic aspect of a swelling of his right clavicle. We performed a two-stage surgical repair using the induced membrane technique described by Masquelet. A complete bone union has been obtained, and patient is satisfied with the cosmetic appearance. In our opinion, the Masquelet technique is a safe and reproducible procedure to treat CPC in high-risk older patients with long gap allowing a rapid and lasting bone union.

Lateral wedge osteotomy for pediatric post-traumatic cubitus varus: Kirschner-wires or locking angular plate?

This study aimed to evaluate and compare two types of internal fixation, locking angular plate (group 1) and Kirschner-wires (group 2), for post-traumatic cubitus varus. The parameters used were Laupattarakasem's criteria (for range of motion in extension/flexion, correction of carrying angle, and the 'lazy S' deformity) and the Barrett's questionnaire (for patient satisfaction). In group I (plate+screws), we had three excellent results and five good. In group II (Kirschner-wires), we had two good results, three fair, and two poor. Statistical analysis showed a better outcome for group I (plate+screws) considering the correction of the humeral-elbow-wrist angle (P<0.003), the postoperative lateral prominence index (P<0.048), and the patient satisfaction (P<0.011). We recommend the locking angular plate, because it can rigidly stabilize the osteotomy, ensuring an excellent functional and cosmetic outcome.

Operative stabilization of the posttraumatic thoracic and lumbar spine: a comparative analysis of the Harrington distraction rod and the modified Weiss spring.

To assess the efficacy of operative stabilization techniques, a retrospective study of Harrington distraction rod (HDR) and modified Weiss spring instrumentation was performed in 90 patients. An operation was performed for one or both of two indications: persistent spine instability or the presence of a neurological deficit in patients with incomplete neurological injuries and myelographic evidence of spinal cord or cauda equina compression. The lateral extracavitary operative approach to the spine for decompression and anterior interbody fusion was performed with an accompanying HDR (47 patients) or modified Weiss spring placement (43 patients). Eight HDRs failed, resulting in gross instability (17 per cent) that either resulted in further neurological injury (1 patient), further surgery (2 patients), or increased morbidity secondary to prolonged bed rest (5 patients). One Weiss spring failed, requiring further surgery (2.3 per cent). Nonsurgical complications were similar in both groups and appeared to be unrelated to the type of instrumentation utilized. The modified Weiss spring instrumentation technique, which offers a dynamic compression fixation of the spine, was clearly superior to the HDR technique, which offers a rigid distraction fixation. The biomechanics of distraction versus compression and rigid versus nonrigid spine stabilization are discussed.

Occipital screw pullout strength. A biomechanical investigation of occipital morphology.

STUDY DESIGN: A three-group design with consistent pullout strength measures. OBJECTIVES: To determine pullout strength of three fixation types (unicortical screws, bicortical screws, wires) and to investigate their correlation with respect to occipital morphology. SUMMARY OF BACKGROUND DATA: A secured, multidirectional occipitocervical fusion requires internal fixation. Devices secured at occipital protuberance were suggested to offer the greatest pullout strength because of this region's thickness. METHODS: Twelve fresh human cadaveric occiputs were sketched with a grid delineating 21 fixation sites. Each site was drilled and hand-tapped. Four specimens were instrumented with unicortical screws on one side of the midline and bicortical screws on the other. Another four were instrumented with bicortical screws and wires, and the remaining four were instrumented with unicortical screws and wires. Two points on each specimen were secured with identical fixation to examine side-to-side symmetry. An MTS materials testing apparatus (MTS Systems Corporation, Eden Prairie, MN) was used to displace the fixators. Pullout strengths at different anatomic locations were recorded. RESULTS: The greatest pullout strength was at the occipital protuberance for all fixation types. The bicortical pullout strength was 50% greater than unicortical. The wire pullout strength was not significantly different from that of the unicortical screw (P > 0.05). Seventy-eight percent of wires broke at 1100 N. Unicortical pullout strength at occipital protuberance was comparable with that of the bicortical screw at other locations. CONCLUSIONS: Unicortical screw fixation at occipital protuberance offers acceptable pullout strength without the potential complications of bicortical screws or wire fixation.

New device for interdental immobilization.

The immobilization of a simple fractured jaw with arch bars is a time-consuming, laborious procedure. The alternative method of immobilization described here uses a precisely threaded, 22-gauge, malleable stainless steel wire and a threaded nylon nut. It affords the surgeon relative safety from accidental puncture trauma and makes the interdental immobilization a precise and speedy procedure.

Evaluation of a new method of small fragment fixation in a medial malleolus fracture model.

OBJECTIVE: To evaluate a new method of small fragment fixation in a medial malleolus fracture model. DESIGN/METHODS: The authors measured the pullout strength, resistance to shear stress, and speed of insertion of 4.0-millimeter partially threaded cancellous screws, 2.4-millimeter smooth K-wires, and a small fragment fixation system with 2.2-millimeter threaded K-wires. Pullout strength was tested in eighty-one synthetic foam blocks and resistance to shear stress in thirty synthetic tibias by use of a servohydraulic testing machine. Six randomized time trials with the threaded K-wires and cancellous screws were also conducted. RESULTS: Pullout strength increased with increasing foam density, increasing insertion depth, and varied with fixation method (p < 0.05). Maximum pullout strengths were as follows: partially threaded cancellous screws, 730+/-4 Newtons; threaded K-wires, 316+/-12 Newtons; and smooth K-wires, 172 +/-5 Newtons. Percent difference in pullout strength between the partially threaded cancellous screw and threaded K-wire diminished with increased depth of insertion and increased foam density. Offset axial load to initiate fracture displacement in a synthetic tibia model averaged 1540+/-138 Newtons for the partially threaded cancellous screws, 1,318+/-117 Newtons for the threaded K-wires, and 1,287+/-121 Newtons for the smooth K-wires (p > 0.05). Average time of fixation of a medial malleolar fragment by orthopedic surgeons with a variety of experience levels in a synthetic tibia with two threaded K-wires (114+/-8 seconds) was significantly faster (p < 0.05) than with two partially threaded cancellous screws (207+/-20 seconds). CONCLUSIONS: Threaded K-wires show substantial pullout strength and similar resistance to offset axial load when compared with partially threaded cancellous screws. These threaded K-wires offer an alternative for the internal fixation of medial malleolus fractures.

Treatment of comminuted intraarticular distal femur fractures with limited internal and external tensioned wire fixation.

OBJECTIVE: Evaluate the treatment of C3 distal femur fractures with limited internal fixation and tensioned wire circular external fixation. DESIGN: Prospective cohort study, from June 1992 to July 1996. SETTING: Urban Level I trauma center. PATIENTS: Sixteen fractures in sixteen patients: nine male, seven female. Fractures: C3.1 one, C3.2 one, C3.3 fourteen. Twelve fractures were open: one GI, seven GII, two GIIIA, one GIIIB, and one GIIIC. INTERVENTION: Fractures were treated with limited open fixation of the condylar joint surface and tensioned wire circular external fixation of the metaphysis and shaft for axial alignment. Three fractures had acute autologous bone grafts. MAIN OUTCOME MEASUREMENTS: The patient's extremity function was evaluated by the authors by using the Sanders et al. Distal Femur Functional Evaluation. RESULTS: Sixteen of sixteen fractures healed. Two patients had delayed bone grafting for delayed union. Average frame time was twenty-five weeks. Average range of motion was 0 to 92 degrees. Five patients had less than 90 degrees of flexion. Five patients required a quadricepsplasty. Average follow-up was thirty-five months. One patient developed a pintract infection. One patient developed septic arthritis, and another developed osteomyelitis. The average Sanders et al. Function knee score was twenty-eight, with a maximum possible score of forty. CONCLUSIONS: C3 fractures of the distal femur are associated with severe soft tissue injuries and bone loss. Loss of function appears to be directly related to these factors. Treatment with limited internal fixation and tensioned wire external fixation has equivalent results to other methods but has a higher incidence of infection and complications. Joint motion is retarded by binding of the soft tissues with fixation wires and pins. The technique is recommended only for salvage of severely comminuted and open fractures of the distal femur with extensive soft tissue injury. Distal femur fractures with moderate comminution and soft tissue injury should be treated with alternate methods.

Strength of fixation of Ludloff metatarsal osteotomy utilizing three different types of Kirschner wires: a biomechanical study.

Static biomechanical studies have demonstrated that the Ludloff shaft metatarsal osteotomy is significantly more stable than other commonly used proximal (basilar) osteotomies, such as the proximal crescentic and the proximal chevron. High average static bending failure moments have been recorded for the screw fixation Ludloff osteotomy construct. The objective of the current study was to find a reasonable alternative method of fixation in cases where a short osteotomy may not be amenable to adequate screw fixation and in cases where an inadvertent intraoperative fracture of the metatarsal occurs and subsequent screw fixation is precarious due to inadequate bone stock. A Ludloff osteotomy was performed on 24 matched pairs of cadaveric specimens to compare the strength of fixation of three different types of Kirschner wires (smooth, threaded, and SOC threaded). Biomechanical testing with plantar force was carried out, and failure load and stiffness were measured for each specimen. The current results indicate that the threaded pin construct provides adequate strength for fixation of the Ludloff osteotomy in the clinical setting.

Stabilization of Lisfranc joint injuries: a biomechanical study.

BACKGROUND: Lisfranc joint injuries are often misdiagnosed, leading to significant morbidity. Methods for anatomic reduction of the tarsometatarsal joint include closed reduction with casting or surgical stabilization with either Kirschner wires and/or cortical screw fixation. Controversy exists as to which fixation technique offers optimal stability. In the present study, the biomechanical stability of three fixation methods was tested: (1) four Kirschner wires, (2) three cortical screws plus two Kirschner wires, and (3) five cortical screws. METHODS: Ten matched pairs of fresh-frozen cadaveric feet were dissected to their ligamentous and capsular elements. The tarsometatarsal ligaments were completely transected to replicate a Lisfranc dislocation; the "injury" was reduced and stabilized using one of the three methods. Biomechanical studies were performed by applying a 100-N cyclic load physiologically distributed to the plantar aspect of the metatarsal heads. Displacement and force measurements were taken from the first and fifth metatarsal heads. Average stiffness of each construct was calculated from the force displacement curves. RESULTS AND CONCLUSIONS: Method 2 provided significantly more stability than Kirschner wire fixation. Method 3 created more stiffness than method 2 at the medial portion of the foot; no statistical difference between the two methods was evident at the lateral foot. CLINICAL RELEVANCE: Cortical screw fixation provides a more rigid and stable method of fixation for Lisfranc injuries as compared to Kirschner wire fixation. This fixation method allows maintenance of anatomic reduction and possibly earlier mobilization with a decreased risk of posttraumatic arthrosis.