Nonbridging external fixation for fractures of the distal radius.

OBJECTIVE: To assess the feasibility of using standard components from the small AO external fixator set to support fractures of the distal radius with a construct incorporating distal fixation in the periarticular radius fragment that would allow for primary mobilization of the wrist joint during fracture healing. METHODS: In a prospective pilot study of a nonbridging external fixator in early 2001, 6 consecutive cases of fracture in the distal radius presenting at a tertiary care centre, the Hamilton General Division of Hamilton Health Sciences, were compared with 6 historical controls treated with a standard bridging construct immobilizing the wrist. Both groups were or had been treated with closed reduction and external fixation of the distal radius under fluoroscopic control. Fracture alignment was measured on radiographs after healing and removal of the fixation devices; additional (secondary) outcome measures were pin-tract sepsis and implant loosening (treatment failure). RESULTS: Compared radiographically with controls, alignments after fracture healing were improved (and virtually anatomic) with use of the nonbridging external fixator. The incidence of pin-tract sepsis was similar in the 2 groups, neither of which included any treatment failures. CONCLUSIONS: Nonbridging external fixation of comminuted distal radius fractures can be accomplished safely and effectively. The results of this pilot study suggest that improved radiographic alignment may be achieved with this technique.     

The radio-radial external fixator in the treatment of fractures of the distal radius

The technique of radio-radial monobloc-fixation with the small AO external fixator device has been applied to 17 consecutive Colles' fractures. The fracture types were mainly A3 and C2, according to the AO classification. We found this technique to be easy and quick in application and stable in fixation. Direct, precise and atraumatic reduction can be achieved by using the distal pins as joy-sticks. Furthermore, disimpaction of the fracture to regain length is possible without bone grafting. Normal carpal mobility and load transfer is preserved during fracture healing and the injured hand can be used in daily life with certain restrictions. To prevent pin-track infections, early mobilization of the wrist should be avoided. We recommend this technique in the treatment of comminuted AO-type A3 fractures of the distal radius and in certain type C2 cases.     

Biomechanical analysis of dynamic external fixation devices for the treatment of distal radial fractures

BACKGROUND: Several dynamic external fixation devices have been introduced to permit early functional treatment of unstable distal radial fractures. METHODS: An intact cadaver wrist was spanned by a dynamic external fixator. Forces between the fixator and the radius were recorded during passive motion using a single, strain-gauged pin. A device with a double ball joint was compared with a new, experimental fixator with 3 degrees of freedom and its center of rotation coincident with that of the wrist. RESULTS: During flexion and extension, the pin load was approximately the same for both fixators. Radioulnar deviation resulted in high pin loads for the fixator with ball joints; the new device showed no considerable pin load. CONCLUSION: The new device has a high degree of kinematic compatibility with the natural wrist joint. When used for the treatment of distal radial fractures, it should provide favorable conditions for the maintenance of fracture reduction compared with a device with an offset ball joint.     

Ilizarov hybrid external fixation for fractures of the distal radius: Part II. Internal fixation versus Ilizarov hybrid external fixation: Stability as assessed by cadaveric simulated motion testing

The in vitro stability of an Ilizarov hybrid external fixator was compared with that of a dorsal 3.5-mm AO T-plate in 8 unpaired, fresh-frozen upper extremities. A specially designed testing device that used computer-controlled pneumatic actuators was used to simulate active finger, wrist, and forearm motions by applying loads to relevant tendons. A comminuted extra-articular distal radius fracture was modelled using a dorsally based wedge osteotomy. Fracture stability was assessed using an electromagnetic tracking device to measure motion across the fracture site after randomized application of the plate and the hybrid fixator. During simulated finger and wrist motions with the forearm pronated or supinated, motion of the distal fragment with the hybrid fixator applied was comparable to or statistically less than with the AO plate applied. During simulated forearm rotation, the stability provided by the 2 fixation types was similar, although the plate allowed statistically less radial-ulnar deviation of the fragment. In this model of a 2-part extra-articular distal radius fracture, the clinically meaningful stability of the Ilizarov hybrid external fixator was comparable to that of the dorsal AO plate.     

Biomechanical characteristics of nonbridging external fixators for distal radius fractures

PURPOSE: Nonbridging external fixation is becoming popular for distal radius fractures, although its biomechanical characteristics have not been documented. This study evaluated the biomechanical characteristics of nonbridging external fixators for distal radius fractures. METHODS: We tested 3 currently available nonbridging fixators (F-Wrist fixator, Hoffman II Compact, and Pennig Dynamic Wrist Fixator) and determined their relative stiffness under axial compression, torsion, and bending moments (dorsal, volar, radial, and ulnar aspects) using a uniform unstable distal radius fracture model. The contact pressure and its total load on the fracture plane were also measured to evaluate the mechanical stimuli at the stable fracture site using a pressure-sensitive conductive rubber sensor. RESULTS: Differences were observed in the stiffness: the Pennig fixator was the stiffest, whereas the F-Wrist fixator was the least rigid. The total load transmitted from the wrist joint to the fracture plane depended on the fixator stiffness in axial compression. CONCLUSIONS: By determining the biomechanical characteristics of nonbridging external fixators, these data may help the clinician when deciding on a particular device for nonbridging external fixation.     

外固定支架结合掌侧入路治疗桡骨远端关节面骨折

目的探讨外固定支架结合掌侧人路治疗桡骨远端关节面骨折的手术指征及临床疗效。方法2000年3月～2005年3月，收治桡骨远端关节面骨折28例，采用背侧外固定支架固定于功能位，掌侧入路以钢板或克氏针固定；骨皮质粉碎或松质骨压缩者予植骨。其中男21例，女7例；年龄18～54岁，中位年龄41岁。左侧4例，右侧24例。根据AO分型标准：C2型18例，C3型10例。合并月骨周围脱位1例。结果4例失访，24例获随访6～18个月，平均8．5个月。X线片示骨折均愈合，桡骨长度无丢失；掌倾角8～16°，平均11．2°，尺偏角19～28°，平均20．8°，均无丢失。按照改良Mcbride评分和纽约骨科医院腕关节评估标准，优16例，良5例，可3例，优良率87％。结论不稳定桡骨远端骨折以及闭合复位难以纠正者应手术治疗。掌侧入路固定能降低并发症，结合外固定支架可获满意复位及功能。     

A convenient dynamic wire traction-fixation method for hand and forearm fractures

We report on a convenient intraoperative distraction technique, called the modified Dynamic Wire-framed Traction (mDWT) method, that assists in fracture reduction and/or is used as an external fixator in patients with unstable distal radius fractures and in other hand and forearm fractures. The mDWT device is easily assembled with wires at the time of surgery, and its configuration produces sufficient longitudinal distraction force that makes reduction easier and facilitates additional fixation procedures. Furthermore, the device can be converted into a simple unilateral external fixator that can be retained postoperatively. Our experience with 13 patients shows that the mDWT method is easy to apply and is a cost-effective technique when used as an intraoperative distraction device or as an external fixator.     

Biomechanical efficacy of an internal fixator for treatment of distal radius fractures.

Despite the effectiveness of external fixation in the treatment of complex wrist fractures, the complication rate for this modality ranges from 20% to 62%. Common complications are related to the use of percutaneous metal pins and result in an average reoperation rate of 16%. In addition, external fixation is unable to prevent dorsal collapse of the radius or maintain the normal palmar tilt of the radiocarpal joint surface. This complication may predispose to posttraumatic wrist instability and arthritis. The problems with external fixation have prompted a search for a better treatment option. An internal fixator placed through limited incisions on the dorsal aspect of the radius and spanning the fracture site can, in theory, provide the benefits of external fixation without the associated morbidity. This study determined the biomechanical efficacy of internal fixators compared with external fixators using a standardized model for an unstable wrist fracture. Two commercially available metal plates were used as internal fixators. Biomechanical testing of the devices was done, and stiffness was determined. Results showed that the internal fixators were significantly stiffer than were the external fixators in axial loading. Failure in axial loading, specifically compression, is a consistent reason for loss of reduction in intraarticular distal radius fractures. The clinical implications of these results suggest that an internal fixator theoretically can prevent loss of reduction in the axial plane and maintain palmar tilt by acting as a rigid dorsal buttress. In addition, the use of an internal fixator potentially decreases the high morbidity associated with external fixation. Additional investigation into the clinical application of internal fixators for distal radius fractures is needed.     

Principles of external fixation and supplementary techniques in distal radius fractures

External fixation for fractures of the distal radius has been used for almost 80 years. The main objective is to gain reduction and maintain the reduction throughout the treatment period. Several fixator concepts are available and selection is based on the complexity of the injury to be treated as well as the surgeon's experience. Periarticular application of the fixator with immediate use of the wrist joint is recommended whenever possible. For intra-articular fractures, transarticular application is advisable. External fixtion in complex fractures has to be supplemented by bone grafting, fixation wires and stabilization of the radioulnar joint. Associated injuries in distal radius fractures need to be identified and treated. The possible complications of external fixation and the means to prevent them are discussed. External fixation of the distal radius has found its place as an established method in treating certain types of this common fracture.     

桡骨远端C型骨折掌侧锁定钢板与外固定架的疗效比较

目的比较掌侧锁定钢板与外固定架治疗桡骨远端C型骨折的疗效。方法采用随机对照法,纳入2014年10月到2017年10月收治的桡骨远端C型骨折患者,随机分为两组,分别采用外固定架或者掌侧锁定钢板治疗。比较两组患者手术时间、术中出血量、骨折愈合时间、术后并发症发生率;比较末次随访时患者腕关节活动度、桡骨掌倾角、尺偏角;比较健、患侧握力比值和患侧腕关节Gartland-Werley评分。结果共纳入30例患者,其中外固定架组14例,掌侧锁定钢板组16例。两组患者术后均随访1年。结果显示,掌侧锁定钢板组手术时间长于外固定架组,术中出血量多于外固定架组,但末次随访时桡骨掌倾角、尺偏角恢复水平优于外固定架组(P<0.05);两组骨折愈合时间,末次随访时腕关节屈伸、旋转活动度,健、患侧握力比,患侧腕关节Gartland-Werley评分等,均未见明显统计学差异(P>0.05);两组患者均未发生术后并发症。结论对于桡骨远端C型骨折,外固定架治疗的手术风险小于掌侧锁定钢板,但会造成术后一定程度的复位丢失,然而这种复位丢失并不影响患者的腕关节功能恢复。     

A biomechanic comparison of an internal radiocarpal-spanning 2.4-mm locking plate and external fixation in a model of distal radius fractures

PURPOSE: To compare the biomechanic stability of distal radius fracture fixation with a new internal radiocarpal-spanning 2.4-mm locking plate, which acts as an internal distal radius fixator, versus a standard distal radius external fixator. The number of locking screws necessary for adequate fracture fixation was also assessed. METHODS: Ten cadaveric specimens were mounted in a loading fixture with cables attached to the 2 flexor and 3 extensor wrist tendons. A 1-cm osteotomy was created to simulate an unstable distal radius fracture. The radiocarpal-spanning locking plate was fixed to the radius and index metacarpal with 4 screws proximally and 4 distally. The specimen was incrementally loaded through the tendons. Motion at the fracture site was determined. Screws were sequentially removed from the construct, the specimen was again incrementally loaded, and fracture motion was measured. The fixation was then changed to an external fixator, and the loading tests were repeated. RESULTS: Fracture fixation with the radiocarpal-spanning 2.4-mm locking plate was significantly more stable with 4 screws proximally and 4 screws distally (4 x 4) and with the 3 x 3 configuration than with the external fixator in both flexion and extension. The 4 x 4 screw configuration was not significantly different from the 3 x 3 screw configuration. The 4 x 4 screw configuration was significantly more stable than the 2 x 2 and 1 x 1 screw configurations in both flexion and extension. All internal fixator configurations and the external fixator showed more fracture displacement at increasingly higher loads. CONCLUSIONS: Fracture fixation with the new internal radiocarpal-spanning 2.4-mm locking plate is more stable than with a standard distal radius external fixator. Only three 2.4-mm locking screws proximally and three 2.4-mm locking screws distally are required for adequate fixation of the locking spanning plate.     

Supplemental pinning improves the stability of external fixation in distal radius fractures during simulated finger and forearm motion

External fixation is commonly used in the treatment of distal radius fractures. In this in vitrod study, we investigated changes in fracture stability when using supplemental radial styloid pinning in combination with external fixation. Eight previously frozen cadaveric upper extremities were mounted in a computer-controlled wrist-loading apparatus. This device was used to generate finger and forearm motions through loading relevant tendons. An unstable extra-articular distal radius fracture was simulated by removing a dorsal wedge from the distal radius metaphysis. An electromagnetic tracking system measured fragment motion following randomized application of a Hoffman external fixator, a Hoffman external fixator with 2 supplemental radial styloid pins, and a dorsal 3.5-mm AO plate. Regardless of the fixation technique used in this unstable fracture model, fragment motion occurred when postoperative finger and forearm motions were simulated. The addition of radial styloid pins to a construct stabilized by an external fixator significantly improved fragment stability, approaching that achieved with the dorsal AO plate. (J Hand Surg 1999;24A:992–1000. Copyright © 1999 by the American Society for Surgery of the Hand.)     

外固定支架结合内固定治疗桡骨远端骨折合并同侧掌指骨骨折

目的探讨外固定支架结合内固定治疗桡骨远端骨折合并同侧掌、指骨骨折的临床疗效。方法对32例桡骨远端骨折合并掌、指骨骨折行Orthofix公司的超关节微型单侧多功能外固定支架结合内固定治疗。结果随访4～11月,平均5．2个月,骨折愈合时间6～12周,平均8周。腕关节功能按Sarmiento标准进行评定：优22例,良8例,可2例;按TAFS评分标准进行功能评估,优28例,良4例。结论对桡骨远端骨折合并掌、指骨骨折,采用超关节微型单侧多功能外固定支架结合内固定治疗,是一种安全实用、简便有效的治疗方法。     

Therapie der distalen Radiusfraktur mittels Fixateur externe

The external fixator has a firmly established place in the treatment of distal radius fractures, including complex fractures (AO C2 and C3). Its use is also indicated for open fractures and compartment syndrome in the lower arm. In the context of “damage control orthopaedics” the external fixator is used in the distal radius as a fast, minimally invasive method of treatment in multiply injured and polytraumatised patients. Open reduction and internal fixation with plates (ORIF) can then be performed after consolidation of the soft tissue mantle and the patient’s general condition. Depending the fracture type and overall injury pattern complete healing can be achieved while the fixator is in place, with further supportive care as appropriate (K-wires, cancellous bone). The downside of treatment with the fixator is the long period of immobilization of the wrist with a protracted rehabilitation. Non-joint-bridging external fixators can have an advantage in individual cases. In the long term, there is no significant difference in the range of movement and strength developed after fracture treatment with internal rather than external fixators.     

Combined internal and external fixation of distal radius fractures

Combined internal and external fixation of distal radius fractures is used most commonly to treat injuries with joint surface or metaphyseal comminution. External fixation aids reduction intraoperatively and facilitates arthroscopic, per-cutaneous, or open manipulation of the fracture.Internal fixation maintains precise reduction of critical anatomy, principally the contour and orientation of the articular surface. Postoperatively the fixator functions as a neutralization device, preventing fracture collapse and decreasing the biomechanical demands on the internal fixation hardware. The combined technique exploits the benefits of both forms of fixation, allowing each to be used to full advantage in the treatment of complex distal radius fractures.     

Treatment of distal radius fracture with the use of calcium phosphate bone cement as a filler

A new procedure for unstable fractures of the distal radius is presented. It uses a nonbridging external fixator in conjunction with calcium phosphate bone cement through a limited exposure. The best indication for the new procedure is intra-articular fracture with some large displaced fragments in young adults. In the C2 or C3 type fractures according to AO classification, it is very difficult to obtain satisfactory fixation with a plate and screws due to comminution of the articular surface and metaphysical bone defects in many instances. After reduction of the articular surface, this new technique allows fixation of the comminuted fragments using half pins of a nonbridging external fixator. Furthermore, injection of calcium phosphate bone to the bone defect helps to make both the articular surface and the cortical bone stable. The nonbridging external fixator allows early exercises. However, it cannot be applied to all types of the fracture because of its structural limitations. The combination of nonbridging external fixation and calcium phosphate bone applications assures early exercise of the wrist.     

植骨内固定与闭合复位支架外固定治疗桡骨远端C型骨折疗效比较

目的：比较植骨内固定与闭合复位支架外固定治疗桡骨远端C型骨折的临床疗效。方法对38例桡骨远端C型骨折患者分别采用植骨内固定(17例)与闭合复位支架外固定(21例)治疗。比较两组术后影像学指标,腕关节功能按Gartland-Werley功能评分标准进行评价。结果患者均获得随访,时间6~18个月。术后3个月掌倾角、桡骨高度内固定组均优于外固定组,差异均有统计学意义( P<0．05)。末次随访腕关节背伸、掌屈、旋前、旋后及 Gartland-Werley 功能评分内固定组均优于外固定组,差异均有统计学意义( P <0．05)。腕关节功能评估：内固定组优6例,良9例,可2例,优良率15/17;外固定组优4例,良10例,可5例,差2例,优良率14/21;两组差异有统计学意义(P<0．05)。结论植骨内固定治疗桡骨远端C型骨折能达到理想复位,能有效防止骨折复位丢失和再移位,临床疗效优于闭合复位支架外固定。     

External fixation of distal radius fractures

External fixation has been used for the treatment of distal radius fractures for more than 50 years. Although the fixator configurations have undergone considerable modification over time, the type of fixator itself is not as important as the underlying principles that provide the foundation for external fixation. Although volar plate fixation is currently in vogue, the indications for external fixation remain largely unchanged. Newer fixator designs have also expanded the traditional usage to include nonbridging applications that allow early wrist motion. The following discussion focuses on the myriad uses for external fixation as well as the shortcomings and potential pitfalls.     

功能性外固定器治疗青壮年桡骨远端C型骨折

目的：研究功能性外顺治疗桡骨远端C型骨折的有效性和治疗效果。方法：自1998年以来,应用自行研制的功能性外固定器治疗桡骨远端C型骨折18例,结果：经3－17个月的随访,复位质量优良率达89％,1年后随功能优良率达94％,平均4．8个月恢复,固定期间背侧固定针松动1例,4个钉孔感染,去除外固定器经换药痊愈,1例正中神经于复固定后即有所改善,2个月后随访恢复正常,骨折愈合时间5－12周,平均10周,结论：该固定器治疗桡骨远端各类型骨折是一种可靠的有效方法,非超关节固定,术后即可行腕关节活动。     

The evaluation of tension in an experimental model of external fixation of distal radius fractures

A cadavaric model was used to evaluate the previously reported methods of determining excessive tension when applying an external fixator across the wrist. An osteotomy of the distal radius was performed and tension was applied incrementally across the joint in 9 cadaveric specimens. The fingers of each specimen could fully flex to the palm at all levels of tension tested. Although the radiocarpal and midcarpal joint spaces did lengthen with incremental changes in the amount of tension, there was no statistically significant correlation that could be made about the difference between the radiocarpal and midcarpal spaces and tension applied across the wrist. Although the carpal height ratio increased significantly from 0 to 10 lb of traction, the carpal height ratio appeared to plateau after further increases in tension. In conclusion, surgeons need to be careful when using any of these previously reported techniques for determining the optimal tension to be applied with an external fixator across the wrist. These techniques may not reproducibly allow the surgeon to detect whether there is excessive distraction across the distal radius fracture.