Fixation strength and pin tract infection of hydroxyapatite-coated tapered pins.

In a multicenter, prospective, randomized study, the biomechanical and clinical properties of the bone-pin interface were compared with standard tapered pins and hydroxyapatite-coated tapered pins implanted in patients who underwent femoral and tibial external fixation treatments. The results showed that the hydroxyapatite-coated tapered pins are clinically effective in improving the strength of fixation of the bonepin interface. This improvement corresponded to a lower rate of pin tract infection. In the hydroxyapatite-coated pin group, there were no differences in strength of fixation between the pins removed from the infected and uninfected pin tracts. In this pin group, the mean pin extraction torque was 531 +/- 225 Ncm in the infected pin tracts and 508 +/- 233 Ncm in the uninfected pin tracts. In the standard pin group, the mean pin extraction torque was 73 +/- 142 Ncm in the infected pin tracts and 211 +/- 216 Ncm in the uninfected pin tracts. The advantages provided by the hydroxyapatite-coated pins were higher in cancellous bone than in cortical bone.     

Alendronate improves screw fixation in osteoporotic bone

BACKGROUND: Animal studies have demonstrated the efficacy of the use of bisphosphonates to enhance screw fixation in bone. In this prospective, randomized study of pertrochanteric fractures treated with external fixation, we tested whether systemic administration of bisphosphonates would improve the fixation of hydroxyapatite-coated screws implanted in osteoporotic bone. METHODS: Sixteen consecutive patients with a pertrochanteric fracture were selected. Inclusion criteria were female gender, an age of at least sixty-five years, and a bone mineral density T-score of less than -2.5 standard deviations. Exclusion criteria included bisphosphonate treatment during the two-year period prior to the fracture. Fractures were fixed with a pertrochanteric fixator and four hydroxyapatite-coated pins. Two pins were implanted in the femoral head (pin positions 1 and 2), and two were placed in the femoral diaphysis (pin positions 3 and 4). The patients were randomized either to therapy with alendronate for a three-month postoperative period (Group A) or to no therapy (Group B). The Group-A patients received an oral dose of 70 mg of alendronate per week. The fixators were removed after three months. RESULTS: All of the fractures healed, and no loss of reduction, nonunion, or delayed union was observed. The combined mean extraction torque (and standard deviation) of the pins implanted at positions 1 and 2 (cancellous bone) was 2558 +/- 1103 N/mm in Group A and 1171 +/- 480 N/mm in Group B (p < 0.0005). The combined mean extraction torque of the pins implanted at positions 3 and 4 (cortical bone) was 4327 +/- 1720 N/mm in Group A and 4075 +/- 1022 N/mm in Group B. CONCLUSIONS: These data show that weekly systemic administration of alendronate improves pin fixation in cancellous bone in elderly female patients with osteoporosis. We observed a twofold increase in extraction torque with the pins implanted in cancellous bone. These results support the use of alendronate in the treatment of osteoporotic pertrochanteric fractures to improve screw fixation in the femoral head.     

Inferior fixation with a new pin design for external fixation: A randomized study in 50 patients operated on by the hemicallotasis technique

Background and purpose?Tibial osteotomy by the hemicallotasis technique (HCO) requires strong pin fixation. We compared pin fixation in HCO using a new self-drilling XCaliber pin (Orthofix) with optimized thread and tip design, with the commonly used standard pin (Orthofix).

Patients and methods?50 patients, mean age 51 (35–66) years, to be treated by HCO were randomized to standard pins or XCaliber pins. In the metaphyseal bone, hydroxyapatite-coated (HA-coated) pins were used in both types of pins. In the diaphyseal bone, non-coated pins were used. The torque forces for insertion and extraction (in Nm) were measured.

Results?The insertion torque was higher for both the proximal and distal standard pins (2.1 Nm (SD 0.9) and 7.0 Nm (1.3), respectively) than for the XCaliber pins (1.3 Nm (0.8) and 3.6 Nm (1.4)). The extraction torque force was higher for the proximal standard pins (4.3 Nm (3.1)) than for the proximal XCaliber pins (1.5 Nm (1.7)) (p < 0.001). The extraction torque for the distal standard pins was 1.9 Nm (2.0) and for the distal XCaliber pins it was 1.4 Nm (1.1).

Interpretation?The commonly used standard pin gives stronger fixation during the treatment of HCO.     

Increased insertion torque delays pin-bone interface loosening in external fixation with tapered bone screws

OBJECTIVE: To test the null hypothesis that osseomechanical integration is not related to the maximum insertion torque of tapered external fixation pins. DESIGN: Prospective in vivo study in a functionally loading ovine model. In 12 animals, tapered commercial external fixation pins were inserted at predefined locations with measured insertion torques and extraction torque measured at 10 weeks postoperatively. SETTING: Unrestricted stall activity under veterinary supervision. INTERVENTIONS: Under general anesthesia and aseptic conditions, mid-diaphyseal tibial osteotomies were created and a 3-mm gap width stabilized with a custom-made, high-precision, single-sided external fixator, in compliance with United Kingdom government regulations [Animals (Scientific Procedures) Act 1986]. MAIN OUTCOME MEASUREMENTS: Primary pin site stability and interface load were assessed by measuring maximum insertion torque (Nm). At a 10-week postoperative end point, osseomechanical stability was assessed by measuring the extraction torque and a pin performance index determined from the insertion/extraction torque ratio. RESULTS: A positive correlation was found between extraction torque and insertion torque (R2 = 0.322, P < 10(-6)). All pins with an insertion torque equal to or greater than 7 Nm had a measurable extraction torque, as did 98% of the pins with an insertion torque above 5 Nm. Extraction torque decreased both as a function of pin site position by the postoperative end point. High insertion torques were found to enhance end point stability in both diaphyseal and metaphyseal bone. CONCLUSION: The data from this study indicate that tapered external fixation pins should be inserted with a high torque to enhance the long-term integrity of the pin-bone interface.     

Hydroxyapatite-coated Schanz pins in external fixators used for distraction osteogenesis : a randomized,controlled trial

BACKGROUND: Complications of external fixation include loosening of the fixation pins and pin-track infection. Laboratory studies and clinical trials have suggested that hydroxyapatite coating improves the osteointegration of various orthopaedic implants. The purpose of this study was to determine whether the prevalence of pin-related complications can be reduced by the use of hydroxyapatite-coated pins in fixators applied for distraction osteogenesis. METHODS: Forty-six consecutive patients undergoing segmental transport or lengthening of the tibia were randomized to the use of either standard titanium Schanz pins or hydroxyapatite-coated stainless-steel Schanz pins. The fixators were used for an average of thirty-eight weeks (range, fourteen to seventy-two weeks). All patients were closely monitored for pin loosening and infection, and digitized radiographs were assessed for bone resorption around all pins. When the external fixator was removed, the torque required to extract the pins was determined with use of an electronic torque wrench. RESULTS: In the control group (titanium pins), twenty-two pins (13%) loosened and an infection occurred at the site of twenty pins. An extensive infection of the canal developed in one patient. Twenty-two pins were removed or replaced because of these complications. In the hydroxyapatite group, no clinical or radiographic signs of pin loosening or infection were observed and no pins required early removal or exchange. The mean torque (and standard deviation) required to remove the hydroxyapatite-coated pins was 0.43 0.18 N-m compared with 0.10 0.09 N-m for the uncoated pins (p < 0.001). CONCLUSION: Coating pins with hydroxyapatite increases their fixation to bone and reduces the rate of infection and loosening during external fixation for distraction osteogenesis. Use of hydroxyapatite-coated pins should be considered in clinical situations requiring prolonged external fixation.     

Hydroxyapatite-coated external-fixation pins. The effect on pin loosening and pin-track infection in leg lengthening for short stature

Pin loosening and infection are inherent complications of external fixation. This study deals with their effects of using either hydroxyapatite (HA)-coated or uncoated external fixation pins in leg-lengthening procedures on patients of short stature. We used HA-coated pins on one side and uncoated pins on the other (randomly determined) in 28 bilateral lengthenings undertaken in 23 patients. A total of 322 pins was used. The mean implantation time was 530 days and the mean lengthening achieved was 78% of initial bone length. Mean extraction torque was 7611.6 Nmm degree(-1) for HA-coated and 85.4 Nmm degree(-1) for uncoated pins (p < 0.001). The rate of pin loosening was 4% (7/161) for HA-coated and 80% (129/161) for uncoated pins (p < 0.001). There was no statistically significant difference in the incidence of pin-track infection between the two groups. The use of HA coating appears to be an effective method of reducing the incidence of pin loosening in external fixation with a long implantation time and for mechanically highly stressed procedures such as leg lengthening for short stature.     

Evaluation of skull thickness and insertion torque at the halo pin insertion areas in the elderly: a cadaveric study

BACKGROUND CONTEXT: The halo skeletal fixator provides the most rigid type of immobilization of all the orthoses that stabilize the cervical spine. Sometimes with older patients (>70 years old), the pin penetrates the cortical and cancellous bone of the skull and enters the intracranial space, which can result in serious complications such as brain injury, infection, hematoma, and loss of cerebrospinal fluid from the subarachnoid space. Currently, there is a lack of relevant literature that examines these concerns. PURPOSE: To evaluate the thickness of the outer table, diploe, and inner table at the anterolateral and posterolateral pin insertion areas of the skull in elderly cadavers by using computed tomography (CT) scans. In addition, insertion torques at the four standard pin insertion areas was determined by applying halo pins at incremental torque in an effort to suggest safe torque levels for the anterolateral and posterolateral pins. STUDY DESIGN/SETTING: A human cadaveric anatomical and biomechanical study relating to thickness and insertion torques at standard pin areas in the elderly. PATIENT SAMPLE: Twenty-one elderly cadaveric skull specimens. OUTCOME MEASURES: Thickness of cortices (tables) and diploe of skull and insertion torque at halo pin insertion areas. METHODS: Aquarius Image software at the CT scanner's TeraRecon Aquarius Workstation was used to make the necessary skull thickness measurements at the pin insertion areas. Six, 8, 12, 18, and 36 inch lb of torque were used to determine penetration of the pins through the inner table at each of the four locations (two anterolateral and two posterolateral). RESULTS: The mean anterolateral thickness was 7.36+/-1.57 mm. The average thickness of the outer table, diploe, and inner table were 2.24+/-0.44 mm, 1.52+/-0.41 mm, and 3.59+/-1.70 mm, respectively. The mean posterolateral thickness was 9.47+/-1.12 mm. The average thickness of the outer table, diploe, and inner table were 4.32+/-0.92 mm, 1.88+/-0.35 mm, and 3.27+/-1.21 mm, respectively. No pin penetration was seen at the traditional 8 inch lb of insertion torque in both the anterolateral and posterolateral pin insertion areas. Eighteen inch lb of torque resulted in penetration in 90.48% (19/21) and in 85.71% (18/21) of specimens in the left anterolateral and right anterolateral pin insertion areas, respectively. No penetration was seen even at 36 inch lb of torque in 80.95% (17/21) of the cadavers in both the left and right posterolateral pin insertion areas. CONCLUSIONS: The current study supported previous research that 8 inch lb of torque is safe for application of halo pins in the elderly. The posterolateral skull is thicker and stronger than the anterolateral skull. The safe maximum torque is 8 inch lb for anterolateral pin insertion area and 18 inch lb for the posterolateral pin insertion area.     

老年股骨粗隆间骨质疏松性骨折外固定术

目的探讨股骨粗隆间骨质疏松性骨折术式的选择和外固定术的可行性,扩大其治疗范围。方法闭合复位,股骨头颈内交叉穿入3枚斯氏针,股骨近段穿入2枚螺纹半针并组合成不规则四边形固定。结果经平均16·3个月的随访,本组25例无脱针、股骨头切割、继发髋内翻等病例,无严重的针道感染,骨折愈合良好。结论骨外固定术具有创伤小、出血少、手术时间短、操作简单等优点,结合头颈内交叉穿针不仅提高了固定的可靠性,而且对伴有骨质疏松的股骨粗隆间骨折具有较好固定作用,尤其对不能耐受内固定术的高龄患者有一定优势。     

Plate fixation with hydroxyapatite-coated screws: a comparative loaded study

The authors evaluated whether AO/ASIF screws coated with hydroxyapatite are better fixed than standard screws in a highly loaded plate fixation animal study. Twelve sheep were divided into two groups. The medial tibial middiaphysis was exposed and a 5-mm long bone cylinder was removed. The tibiae were fixed with six-hole dynamic compression plates. Six sheep received standard AO/ASIF stainless steel cortical screws (Group A), and six sheep received AO/ASIF stainless steel cortical screws coated with hydroxyapatite (Group B). Three months after surgery, the sheep were euthanized. The mean screw insertion torque was 4800 +/- 768 N/mm in Group A and 4847 +/- 450 N/mm in Group B. The mean screw extraction torque was 530 +/- 374 N/mm in Group A and 3733 +/- 849 N/mm in Group B. Extraction torque of Group A was significantly lower compared with the corresponding insertion torque. In Group B, there were no differences between extraction and insertion torque. Morphologic analyses showed marked fibrous tissue encapsulation in Group A and bone to screw direct contact in Group B. The results confirm that hydroxyapatite-coated AO/ASIF screws prevent deterioration of screw anchorage, even under highly loaded conditions. By using hydroxyapatite-coated screws, complications resulting from inadequate fixation could be avoided.     

Fractures of the distal radius treated with a nonbridging external fixation technique using multiplanar k-wires

PURPOSE: Joint-bridging external fixation is a minimally invasive treatment option for distal radius fractures. Although radial length can be restored easily the anatomic reduction of articular fragments and restoration of the normal volar tilt proves to be more difficult. A method of nonbridging hybrid fixation of distal radius fractures facilitates fracture reduction and allows for free wrist movement. METHODS: Twenty-five consecutive patients with fractures of the distal radius were treated with nonbridging external fixation for 6 weeks. The stepwise surgical technique comprised a preliminary joint-bridging construction for reduction purposes, the subsequent insertion of 3 to 4 K-wires in the distal fragment, the assembling of wires to a bar nearly parallel to the fracture line, and lastly the removal of the joint-bridging part. Clinical and radiologic evaluation was performed on the first and seventh days and at 6 weeks and 2 years after surgery. RESULTS: All fractures united. Palmar tilt (> or =0 degrees ) and articular surface (articular step-off < 2 mm) were restored in all patients whereas loss of radial length occurred in 4 patients having the distal fracture fragment secured with 3 K-wires. No radial shortening was seen in fractures with 4 K-wires inserted in the distal fragment. Functional results at 2 years after surgery showed an average extension of 55 degrees and flexion of 64 degrees without significant differences between extra-articular and intra-articular fractures. There was no extensor tendinitis or pin loosening in the distal fragment; however, 3 pin track infections of proximal pins occurred. CONCLUSIONS: This surgical technique of nonbridging external fixation is a good treatment option for distal radius fractures: it permits wrist movement. We recommend the insertion of 4 K-wires in the distal fracture fragment.     

A comparison of plate and pin fixation for arthrodesis of the rheumatoid wrist

This retrospective study compared plate fixation versus pin fixation in 57 patients with rheumatoid arthritis who underwent wrist arthrodesis. Fixation was achieved by using plates in 32 patients and longitudinal pins in 25 patients. Clinical follow-up averaged 29 months (range: 12-57 months) and radiographic follow-up averaged 16 months (range 12-39 months). Union occurred in 97% of the wrists fixed with plates and in 96% of the wrists fixed with pins. There were 6 (19%) complications in the plate group and 7 (28%) complications in the pin group. Three (12%) wrists fixed with pins moved from the immediate postoperative position to a position of relative volar flexion, while radiographs showed no changes in wrist position in the plate group. With both methods, successful arthrodesis stabilized the wrist in a high percentage of patients. Plate fixation offers an excellent alternative method for arthrodesis of the rheumatoid wrist.     

Antimicrobial efficacy of external fixator pins coated with a lipid stabilized hydroxyapatite/chlorhexidine complex to prevent pin tract infection in a goat model.

BACKGROUND: Pin tract infection is a common complication of external fixation. An antiinfective external fixator pin might help to reduce the incidence of pin tract infection and improve pin fixation. METHODS: Stainless steel and titanium external fixator pins, with and without a lipid stabilized hydroxyapatite/chlorhexidine coating, were evaluated in a goat model. Two pins contaminated with an identifiable Staphylococcus aureus strain were inserted into each tibia of 12 goats. The pin sites were examined daily. On day 14, the animals were killed, and the pin tips cultured. Insertion and extraction torques were measured. RESULTS: Infection developed in 100% of uncoated pins, whereas coated pins demonstrated 4.2% infected, 12.5% colonized, and the remainder, 83.3%, had no growth (p < 0.01). Pin coating decreased the percent loss of fixation torque over uncoated pins (p = 0.04). CONCLUSION: These results demonstrate that the lipid stabilized hydroxyapatite/chlorhexidine coating was successful in decreasing infection and improving fixation of external fixator pins.     

Transarticular versus extraarticular ankle pin fixation: a biomechanical study

BACKGROUND: Transarticular pin fixation for ankle stabilization has drawbacks, including ankle joint arthrosis. An extraarticular technique could help avoid these problems. We compared stiffness under minimal dorsiflexion loading with transarticular versus extraarticular fixation. METHODS: Cadaveric specimens from ten lower extremity matched pairs were randomized to receive transarticular or extraarticular fixation. For transarticular fixation, axial pins were passed retrograde through the plantar heel, calcaneus, subtalar joint, talar body, and ankle joint. For extraarticular fixation, the first pin was inserted antegrade from the anterior distal tibia to the posterolateral aspect of the calcaneus tuberosity. The second pin was inserted percutaneously antegrade from the distal medial tibial metaphysis to the dorsal navicular, passing anterior to the ankle and dorsal to the talonavicular joint. Each specimen was subjected to 1000 cycles at 5 mm/s to 100 N. After testing, the extraarticular specimens were dissected to establish the distance of the pin from the flexor hallucis longus (FHL) tendon. RESULTS: There was no significant difference in stiffness between the transarticular and the extraarticular group (mean+/-standard error of the mean) (17.93 N/mm+/-1.0 N/mm and 18.61 N/mm+/-1.07 N/mm, respectively). The lateral pin was 4.2+/-1.4 mm (range, 2.5 to 6.0 mm) from the FHL. CONCLUSIONS: Fixation stiffness with extraarticular crossed antegrade pins was not different from that of transarticular fixation and did not disrupt the ankle or the plantar skin. CLINICAL RELEVANCE: Extraarticular ankle fixation may help avoid the complications found with the joint, cartilage, and plantar skin disruption associated with transarticular fixation.     

Complications of smooth pin fixation of fractures and dislocations in the hand and wrist.

A retrospective review of patients treated with internal fixation of fractures or dislocations of the hand or wrist over a four-year period was undertaken to determine the complication rates of pin fixation for stabilization of these injuries. One hundred thirty-seven patients who received 422 pins were studied. All pins were unthreaded, measured 0.035-0.069 inches (0.9-1.8 mm) in diameter, were placed with a power drill, and were left protruding through the skin. The mean time that pins were left in place was 6.5 weeks, (range, two days to 24 weeks). Minimum follow-up time was 43 days after pin removal. Thirty-four complications occurred in 24 patients, and the overall complication rate was 18%. Forty-five of the 422 pins were involved (11%). Complications included infections in ten patients (7%), pin loosening without infection in six (4%), loss of reduction in six (4%), symptomatic nonunion in six (4%), impaled flexor tendon in two (2%), asymptomatic pseudarthrosis in one (1%), pin migration in one (1%), median nerve injury in one (1%), and radial artery injury in one (1%). Osteomyelitis developed in two of the patients with infections. Pin tract infection occurred at a mean time of ten weeks and aseptic loosening at a mean time of eight weeks. The frequent complication rates emphasize the need for meticulous pin placement, adequate intraoperative evaluation of pin position, and satisfactory patient compliance. Despite the frequency of these complications, serious permanent sequelae did not occur in most patients.     

Behandlung epiphysär-metaphysärer Frakturen bei Kindern mit einem neuartigen Implantat

OBJECTIVE: Improvement of stability of internal fixation of epiphyseo-metaphyseal fractures in children with an implant characterized by its small diameter, easy utilization and its versatility. It avoids the drawbacks of screw fixation particularly in respect to the growth plate. INDICATIONS: Potentially all epiphyseo-metaphyseal fractures in children. CONTRAINDICATIONS: None. Crossing of the growth cartilage by small pins (< 2 mm) is without consequences under the condition that no compression is applied and that correction of a faulty pin position is limited to one. SURGICAL TECHNIQUE: In general, two threaded pins are used. They are inserted in a divergent fashion after the fracture has been reduced. Percutaneous insertion is possible. An adjustable lock screwed on a special key is slid over the end of the pin and put in contact with bone. It is squeezed until the key breaks off. The pins are then shortened. RESULTS: Since November 1999 these pins have been used for six olecranon fractures. In January 2002 we extended the indication to other fracture sites. Between January 2002 and July 2003 this system has been used 37 times (six olecranon fractures, eleven lateral condylar fractures and 13 medial epicondylar fractures of the elbow, and seven fractures of the ankle). A total of 43 fractures were treated (20 girls, 23 boys, average age 9.8 +/- 3.6 years) Average duration of follow-up 16.8 +/- 4.7 months. The assessment of results was based on technical, radiographic, and functional aspects. The overall results were good, in particular in respect to the stability of implants and the functional results. No secondary displacement, nor nonunion were observed; the pins were removed in all children at 6 weeks. The ease of handling the implants and the good clinical and radiologic results led us to propose these pins for routine use in epiphyseal and epiphyseo-metaphyseal fractures in children. Some improvements, however, are indicated principally, in particular in respect to the control of compression achieved by the adjustable lock.     

Monoaxial external fixation of the calcaneus: An anatomical study assessing the safety of monoaxial pin insertion

The use of external fixation for intra-articular calcaneal fractures is increasing in popularity. Studies have shown fine wire and monoaxial external fixation to be a viable surgical alternative to more invasive methods of open reduction and internal fixation of the calcaneus. However, there is an absence of literature that quantifies the risk of pin insertion for monoaxial fixation.This study aimed to determine the safety of inserting monoaxial pins within the calcaneus to house the Orthofix Calcaneal Mini-Fixator. Five formalin embalmed cadaveric ankle and lower leg specimens were inserted with six monoaxial pins. Careful dissection then revealed the presence of the tendons of peroneus longus and brevis, the sural nerve and the small saphenous vein in relation to these pins. Measurements from each pin to each of these structures were made as the structures transected lines drawn from each pin to two palpable bony landmarks: the inferior tip of the lateral malleolus and the posterosuperior calcaneus. In doing this, the risk posed by each pin could be evaluated. We found that two particular pins, those used to hold the articular surface of the subtalar joint in a reduced position, posed a larger risk of injury to surrounding structures than the remaining pins. These findings therefore suggest that monoaxial fixation of the calcaneus using a six pin approach is a relatively safe method of rectifying calcaneal fractures and thus may serve as a welcome alternative to other methods of calcaneal fixation.     

The effect of pin location on the rigidity of the halo pin-bone interface

Optimal insertion of halo fixation pins to maximize the rigidity of the interface between the halo pins and the outer table of the skull is important in reducing the incidence of pin loosening. An in vitro biomechanical study was performed using cadaver skulls to investigate the effects of pin location on the rigidity of this pin-bone interface. Halo pins were inserted at nine positions within a recommended "safe zone" for pin insertion. It was found that the rigidity of the pin-bone interface progressively decreased as pins were inserted more superiorly on the calvaria. The rigidity of the interface did not change significantly when the location of the pins was varied in the horizontal axis. This reduction in interface rigidity associated with inserting pins more superiorly on the skull may be related to an increase in the angle of insertion of the pins with respect to the surface of the calvaria. Based on this study, a change in the technique of halo pin insertion is recommended. Pins should be placed as inferiorly as possible, close to the supraorbital ridge, to achieve the most perpendicular angle of insertion and thus the most rigid fixation. The improved rigidity obtained with perpendicular pin insertion may minimize the rate of pin loosening and other complications associated with use of the halo orthosis.     

Lateral versus crossed wire fixation for displaced extension supracondylar humeral fractures in children

Reduction and percutaneous pin fixation is widely accepted treatment for displaced humeral supracondylar fractures in children, but the best pin configuration is still debatable. This study examined the outcome for crossed and lateral pins placement in type IIB and III supracondylar humeral fractures. Clinical notes and radiographs of 131 children with an average age of 6 years were retrospectively reviewed. Lateral pins fixation was used in 66 children and crossed wires in 65. The groups were similar with regard to gender, age, follow-up, severity of displacement and number of closed/open reductions. There was no statistical difference between the two groups either clinically or radiologically in the quality of outcome. However, postoperative ulnar nerve injuries occurred in 6% of patients treated with crossed wire fixation, whilst none of the group with pins inserted laterally suffered this complication. We recommend fixation of displaced humeral supracondylar fractures with two or three lateral pins inserted parallel or in a divergent fashion. This method of fixation gives similar results to crossed wires but prevents iatrogenic ulnar nerve injuries.