Internal fixation of dorsally comminuted fractures of the distal part of the radius: a biomechanical analysis of volar plate and intramedullary nail fracture stability

Introduction  

The purpose of the present study was to carry out biomechanical testing of “new generation” volar plates and an intramedullary nail.     

Volar neutralization plate fixation of dorsally displaced distal radius fractures

Open reduction and volar neutralization plate fixation avoids problems associated with dorsal plate fixation (eg, extensor tenosynovitis and tendon rupture) and minimizes the necessity for secondary plate removal. Volar plating is a useful technique for treating dorsally displaced distal radius fractures with minimal scarring, infrequent bone grafting, and safe early wrist mobilization.     

掌侧锁定加压钢板治疗桡骨远端背侧不稳定性骨折

[目的]探讨掌侧入路“T”形锁定加压钢板（T-LCP）治疗桡骨远端背侧不稳定性骨折的初期疗效。[方法]总结2003年9月～2005年11月经掌侧入路T-LCP内固定治疗桡骨远端背侧不稳定性骨折9例。男3例，女6例，年龄52～74岁，平均63．5岁。按AO分类标准：B2型2例，B3型1例，C1型2例，C2型3例，C3型1例，均为闭合性骨折。所有病例均采取掌侧入路，术中不显露背侧组织，骨缺损严重者置入人工骨（Osteoset）。[结果]9例全部获得随访，平均10．7个月（6～17个月）。X线片显示骨折全部Ⅰ期愈合，平均愈合时间为7周。1例骨缺损严重，术中置入人工骨（Osteoset）。所有病例均无感染、骨不连、钢板松动、腕管综合征、正中神经炎等并发症。术后功能康复时间6～29周，平均12．5周。术后第1d开始被动活动腕关节，1周后主动活动，功能锻炼。按改良的Mcbride腕关节功能评价标准：优7例，良1例，可1例，优良率为88．9％。[结论]经掌侧入路T-LCP治疗桡骨远端背侧不稳定骨折，内固定可靠，允许早期功能锻炼，疗效佳。     

Wire-loop fixation of volar displaced osteochondral fractures of the distal radius.

We describe the technique of wire-loop fixation to treat 4 young men with a unique variant of Melone's type 4 articular fracture of the volar lunate facet, characterized by a displaced rotated articular fragment supported by a limited amount of subchondral bone. This is an unusual injury that threatens the integrity of both the radiocarpal and distal radioulnar joints. It is the result of a compressive force to the wrist and may require trispiral computed tomography for delineation. Open reduction and internal fixation is recommended to maintain stability and articular congruity. The displaced volar-articular fragment, however, may be relatively small; therefore, direct manipulation could lead to soft tissue stripping and osteonecrosis. We have found the technique of wire-loop fixation to be a simple, reproducible, and effective alternative method of internal fixation for these difficult fractures. Malunion, nonunion, loss of fixation, tendon rupture, infection, arthrosis, or pain caused by hardware has not occurred. Use of this technique is not recommended in patients with osteoporotic bone.     

Non-bridging external fixation employing multiplanar K-wires versus volar locked plating for dorsally displaced fractures of the distal radius

Background

The aim of this study was to compare non-bridging external fixation to palmar angular stable plating with respect to radiological outcome, wrist function, and quality of life.

Methods

One hundred and two consecutive patients (mean age: 63 years) were enrolled in the study. Fifty-two patients were randomized for plate osteosynthesis (2.4 mm, Synthes), 50 patients received non-bridging external fixation (AO small fixator). Objective (range of motion, grip strength), patient rated outcomes (quality of life, pain), and radiological outcome were assessed 8 weeks, 6 months, and 1 year after surgery.

Results

Loss of radial length of more than 3 mm was not detected in any group. Volar tilt was better restored by external fixation (7.2°) than by volar plating (0.1°). Wrist function was good in both groups. The external fixator was tolerated very well, and the quality of life assessment revealed comparable results in both groups. Osteoporosis was found in 54 % of patients and had no influence on radiological and functional outcome.

Conclusion

Non-bridging external fixation employing multiplanar K-wires is a suitable treatment option in intra- and extra-articular fractures of the distal radius even in osteoporotic bone.

Level of evidence

Prospective randomized trial, Level I.     

Initial experience with the Forte plate for dorsally displaced distal radius fractures

Open reduction and plate osteosynthesis is occasionally indicated for dorsally displaced distal radius fractures. We reviewed our medium term results with the Forte plate, one of the recently introduced purpose-made implants.Twenty-five patients operated on during the first year were reviewed 19 (12-24) months after surgery. Median age at operation was 53 (28-80) years. There were seven high energy and eighteen low energy injuries. Fourteen fractures extended into the radiocarpal joint.Three patients had a poor clinical result and were re-operated on before review with an arthrodesis, ulnar shortening, or Sauve-Kapandji operation. The remainder had six excellent, twelve good, and four fair results. Irritation of the extensor tendons was a minor problem.Initial radiological correction of deformity was satisfactory, but increased volar angulation of the distal radius was seen at follow up in twenty patients - by more than 10 degrees in nine. Seven patients had 20-30 degrees volar tilt at final review and tended to have a poorer clinical result than other patients.In our patients use of the Forte plate seems to have given satisfactory clinical results, but the increase in volar tilt after surgery is a cause for concern.     

A biomechanical comparison of two volar locked plates in a dorsally unstable distal radius fracture model

BACKGROUND: This study compares the biomechanical stability of two volar locked plate systems for fixation of unstable, extra-articular distal radius fractures. METHODS: In six matched pairs of fresh frozen cadaveric specimens, a simulated unstable, extra-articular distal radius fracture was created. The fractures were stabilized with one of two types of volar locked plates. Specimens were axially loaded at five different positions: central, volar, dorsal, radial, and ulnar. Initial (precyclic loading) stiffness of each locked plate system was calculated. Each specimen was then loaded for 5,000 cycles with an 80 N central load. Finally, specimens were axially loaded at the same five positions to calculate the postcyclic loading stiffness of each volar locked plate system. Main outcome measurements were precyclic loading stiffness, postcyclic loading stiffness, maintenance of stiffness after cyclic loading, and amount of fracture displacement between the two volar locked plate systems. RESULTS: There were no differences in maintenance of stiffness and fracture displacement following cyclical loading between the two volar plate systems. After cyclic loading, the distal volar radius (DVR) locked plate was significantly stiffer than the Synthes volar locked plate in volar loading only (p < 0.01). CONCLUSION: Materials properties and design differences between these systems did not provide enough biomechanical difference to support use of either implant over the other. With this in vitro model, both implants provided adequate stability to resist physiologic loads expected during therapy in the initial postoperative period.     

Locking versus nonlocking T-plates for dorsal and volar fixation of dorsally comminuted distal radius fractures: a biomechanical study

PURPOSE: To see if locking volar plates approach the strength of dorsal plates on a dorsally comminuted distal radius fracture model. Volar plates have been associated with fewer tendon complications than dorsal plates but are thought to have mechanical disadvantages in dorsally comminuted distal radius fractures. Locking plates may increase construct strength and stiffness. This study compares dorsal and volar locking and nonlocking plates in a dorsally comminuted distal radius fracture model. METHODS: Axial loading was used to test 14 pairs of embalmed radii after an osteotomy simulating dorsal comminution and plating in 1 of 4 configurations: a standard nonlocking 3.5-mm compression T-plate or a 3.5-mm locking compression T-plate applied either dorsally or volarly. Failure was defined as the point of initial load reduction caused by bone breakage or substantial plate bending. RESULTS: No significant differences in stiffness or failure strength were found between volar locked and nonlocked constructs. Although not significant, the stiffness of dorsal locked constructs was 51% greater than that of the nonlocked constructs. Locked or nonlocked dorsal constructs were more than 2 times stiffer than volar constructs. The failure strength of dorsal constructs was 53% higher than that of volar constructs. Failure for both volar locked and nonlocked constructs occurred by plate bending through the unfilled hole at the osteotomy site. Failure for both dorsal locked and nonlocked constructs occurred by bone breakage. CONCLUSIONS: Locking plates failed to increase the stiffness or strength of dorsally comminuted distal radius fractures compared with nonlocking plates. Failure strength and stiffness are greater for locked or nonlocked dorsal constructs than for either locked or nonlocked volar constructs. Whether the lower stiffness and failure strength are of clinical significance is unknown. The unfilled hole at the site of comminution or osteotomy is potentially a site of weakness in both volar locked and nonlocked plates.     

Combined dorsal and volar plate fixation of complex fractures of the distal part of the radius

BACKGROUND: Fractures of the distal part of the radius that are associated with complex comminution of both the articular surface and the metaphysis (subgroup C3.2 according to the Comprehensive Classification of Fractures) are a challenge for surgeons using standard operative techniques. METHODS: Twenty-five patients with subgroup-C3.2 fractures that had been treated with combined dorsal and volar plate fixation were evaluated at an average of twenty-six months after the injury. Subsequent procedures included implant removal in twenty-one patients and reconstruction of a ruptured tendon in two patients. RESULTS: An average of 54 degrees of extension, 51 degrees of flexion, 79 degrees of pronation, and 74 degrees of supination were achieved. The grip strength in the involved limb was an average of 78% of that in the contralateral limb. The average radiographic measurements were 2 degrees of dorsal angulation, 21 degrees of ulnar inclination, 0.8 mm of positive ulnar variance, and 0.7 mm of articular incongruity. Seven patients had radiographic signs of arthrosis during the follow-up period. A good or excellent functional result was achieved for twenty-four patients (96%) according to the rating system of Gartland and Werley and for ten patients (40%) according to the more stringent modified system of Green and O'Brien. CONCLUSIONS: Combined dorsal and volar plate fixation of the distal part of the radius can achieve a stable, mobile wrist in patients with very complex fractures. The results are limited by the severity of the injury and may deteriorate with longer follow-up. A second operation for implant removal is common, and there is a small risk of tendon-related complications.     

Volar fixation of dorsally displaced distal radial fracture using locking compression plate

PURPOSE: To evaluate the functional and radiological results of treating unstable fractures of the dorsal distal radius with a volar locking plate. METHODS: Dorsally displaced distal radial fractures in 30 patients (11 men and 19 women; mean age, 58.6 years) were fixed by volar locking compression plate and followed up for a minimum of one year. RESULTS: At final functional assessment, 24 patients achieved excellent and 5 achieved good outcomes, with one patient exhibiting fair results. Radiological scores demonstrated 22 excellent and 8 good outcomes. No nonunion or infection occurred. CONCLUSION: Volar locking compression plating is a safe and effective treatment for unstable fractures of the dorsal distal radius.     

Volar fixation for dorsally displaced fractures of the distal radius: a preliminary report

Using a volar approach to avoid the soft tissue problems associated with dorsal plating, we treated a consecutive series of 29 patients with 31 dorsally displaced, unstable distal radial fractures with a new fixed-angle internal fixation device. At a minimal follow-up time of 12 months the fractures had healed with highly satisfactory radiographic and functional results. The final volar tilt averaged 5 degrees; radial inclination, 21 degrees; radial shortening, 1 mm; and articular incongruity, 0 mm. Wrist motion at final follow-up examination averaged 59 degrees extension, 57 degrees flexion, 27 degrees ulnar deviation, 17 degrees radial deviation, 80 degrees pronation, and 78 degrees supination. Grip strength was 79% of the contralateral side. The overall outcome according to the Gartland and Werley scales showed 19 excellent and 12 good results. Our experience indicates that most dorsally displaced distal radius fractures can be anatomically reduced and fixed through a volar approach. The combination of stable internal fixation with the preservation of the dorsal soft tissues resulted in rapid fracture healing, reduced need for bone grafting, and low incidence of tendon problems in our study.     

Palmar plating for dorsally displaced fractures of the distal radius

Extensor tendon rupture and irritation caused by implants or surgical intervention are serious complications in the treatment of fracture of the distal radius when a dorsal approach is used. To prevent complications, the dorsally displaced fracture of the distal radius was treated using a palmar approach. The subjects were 18 men and 15 women with a mean age of 54 years at the time of the injury (range, 23-75 years). All the patients had internal fixation with a plate and screws using the palmar approach. Union was achieved in all patients. Radiographic parameters, including the palmar tilt, radial inclination, radial length, and ulnar variance have been maintained since the operation. According to the rating scale of Gartland and Werley, there were 12 excellent, 20 good, and one fair result. There were no extensor tendon injuries that occurred during use of the palmar approach in this small series of patients. Palmar plating can be safe and effective for treatment of a dorsally displaced fracture of the distal radius.     

掌侧与背侧钢板固定关节外桡骨远端背侧粉碎性骨折的生物力学研究

目的 探讨掌侧与背侧钢板固定桡骨远端背侧粉碎性骨折时的抗压缩、抗扭转差异性.方法 将12侧新鲜成人尸体桡骨标本制成桡骨远端背侧粉碎性骨折模型,随机分为2个大组,分别进行掌侧与背侧钢板螺钉固定;再将每个大组分为2个亚组,分别进行轴向压缩试验和水平扭转试验.检测指标:轴向压缩强度、轴向压缩刚度、水平扭转强度和水平扭转刚度.结果 在轴向压缩试验中,掌、背侧两组之间轴向压缩强度差异有统计学意义(P＜0.05),背侧组大于掌侧组;在生理压缩载荷下,掌、背侧两组刚度值差异有统计学意义(P＜0.05),背侧组高于掌侧组.在水平扭转试验中,两组水平扭转强度与扭转刚度差异都没有统计学意义,但数据显示,掌侧组都略强于背侧组.结论 在抗压缩方面,两组的压缩强度以及压缩刚度差异均有统计学意义,背侧组要优于掌侧组;而在抗旋转方面,两组的扭转强度与扭转刚度差异均无统计学意义,但掌侧组在数据上均稍大于背侧组.     

A biomechanical comparison between two volar locking plate systems for distal radius fractures

The biomechanical properties of two distal radius volar locking plate systems were investigated. A cadaveric model simulating distal radius fractures with dorsal comminution was selected. The biomechanical properties of fracture fixation using the Synthes volar locking T-plate and the Hand Innovation DVR plate were characterized. The average stiffness was 137.1 +/- 19.9 N/mm for the DVR group and 119.1 +/- 9.9 N/mm for the Synthes group (P = .49), and the average changes of the opening angle describing plastic deformation were 10.1 degrees +/- 4.0 degrees and 8.6 degrees +/- 13.2 degrees, respectively (P = .23). This study demonstrates that both the Synthes T-plate and Hand Innovations DVR plate fixation systems show comparable biomechanical characteristics.     

桡骨远端骨折掌侧与背侧接骨板固定的生物力学比较

目的 比较背侧移位桡骨远端骨折掌、背侧接骨板内固定后的生物力学性能,为桡骨远端骨折的治疗策略提供实验依据.方法 取6对12块人体桡骨远端标本,制作背侧移位桡骨远端骨折模型,配对标本一侧采用接骨板掌侧内固定,另一侧采用接骨板背侧内固定,固定完成后置于材料测试机上进行轴向压缩实验,实验模式为载荷破坏实验,记录载荷一位移曲线,获得标本破坏时的载荷和骨吸收的能量,实验结果进行统计学配对处理.结果 5对标本在轴向载荷下向掌侧发生成角倾斜,1对标本在轴向载荷下发生骨折端的嵌插.掌侧接骨板固定组的平均破坏载荷为[(1 520.05±579.56)N,x±s,下同],破坏时骨吸收的能量平均为(10.04 ±3.62)J;背侧接骨板固定组的平均破坏载荷为(1 326.77±384.86)N,标本破坏时骨吸收的能量平均为(8.21±3.74)J,组间对比差异无统计学意义(P>0.05).结论 掌侧接骨板固定是治疗桡骨远端骨折理想的固定方式.