Clinical and Radiographic Outcomes of Unipolar and Bipolar Radial Head Prosthesis in Patients with Radial Head Fracture: A Systemic Review and Meta-Analysis

Purpose: To compare clinical outcomes of unipolar and bipolar radial head prosthesis in the treatment of patients with radial head fracture. Materials and Methods: Medline, Cochrane, EMBASE, Google Scholar databases were searched until April 18, 2016 using the following search terms: radial head fracture, elbow fracture, radial head arthroplasty, implants, prosthesis, unipolar, bipolar, cemented, and press-fit. Randomized controlled trials, retrospective, and cohort studies were included. Results: The Mayo elbow performance score (MEPS), disabilities of the arm, shoulder, and hand (DASH) score, radiologic assessment, ROM, and grip strength following elbow replacement were similar between prosthetic devices. The pooled mean excellent/good ranking of MEPS was 0.78 for unipolar and 0.73 for bipolar radial head arthroplasty, and the pooled mean MEPS was 86.9 and 79.9, respectively. DASH scores for unipolar and bipolar prosthesis were 19.0 and 16.3, respectively. Range of motion outcomes were similar between groups, with both groups have comparable risk of flexion arc, flexion, extension deficit, rotation arc, pronation, and supination (p values <0.001 for both unipolar and bipolar prosthesis). However, bipolar radial head prosthesis was associated with an increased chance of heterotopic ossification and lucency (p values ≤0.049) while unipolar prosthesis was not (p values ≥0.088). Both groups had risk for development of capitellar osteopenia or erosion/wear (p values ≤0.039). Conclusion: Unipolar and bipolar radial head prostheses were similar with respect to clinical outcomes. Additional comparative studies are necessary to further compare different radial head prostheses used to treat radial head fracture.     

Radial Head Fractures: Indications and Technique for Primary Arthroplasty

Abstract The treatment of complex radial head fractures remains a challenge for the orthopedic surgeon. Novel implants and improved surgical techniques have made reconstruction of the radial head with open reduction and internal fixation possible in most cases. However, extremely comminuted radial head fractures with associated instabilities still require replacement of the radial head with a prosthesis to allow rehabilitation with early motion of the elbow, and thereby optimizing the functional results of these potentially devastating injuries. In this article we discuss the surgical considerations related to radial head replacement, encompassing the indications for radial head arthroplasty, implant selection, surgical technique, rehabilitation protocols, and complications related to radial head prosthesis.     

桡骨小头粉碎性骨折两种手术方法的疗效分析

目的比较研究桡骨小头切除术与桡骨小头置换术治疗MasonⅢ、Ⅳ型桡骨小头粉碎性骨折的临床疗效。方法1997年1月至2006年5月，共收治26例MasonⅢ、Ⅳ型桡骨小头粉碎性骨折，14例行桡骨小头切除术，12例行桡骨小头置换术。对两组患者的肘、腕关节的疼痛、运动、肌力、X线表现以及肘关节功能评分进行了比较研究。结果两组分别平均随访5．2年和2年，切除组平均肘关节痛觉及视觉模拟（VAS）评分为18．7分，置换组为23．5分（P〈0．01）；切除组肘关节伸直角度平均-12．4°置换组平均5．8°（P〈0．01）；切除组肘关节屈曲度、前臂旋转活动度与置换组差异无显著性差异（P〉0．05）。但两组的伸肘、旋前以及旋后肌力减弱差异有显著性差异（P〈0．01）；切除组提携角平均增大8．7°、桡骨移位2．1mm，置换组分别为1．3°和0．3mm，差异有显著性差异（P〈0．01）；切除组Broderg和Morrey肘关节功能评分平均为80．3分，置换组为91．3分（P〈0．01）。结论与桡骨小头切除术相比，桡骨小头置换术治疗MasonⅢ、Ⅳ型桡骨小头粉碎性骨折可获得较满意的关节活动范围、得到较大的肌力恢复以及良好的关节功能恢复。     

Elbow Biomechanics,Radiocapitellar Joint Pressure,and Interosseous Membrane Strain Before and After Radial Head Arthroplasty

Complex radial head fracture and elbow instability can be treated with radial head arthroplasty. Good clinical results have been described after this surgical treatment. However, the revision and complication rate reported in the literature is concerning. This might be due to altered kinematics after radial head arthroplasty. Eight human native elbows were examined with dynamic radiostereometric analysis and compared with a radial head arthroplasty. Translations of the radial head in the x-, y-, and z-directions relative to the humerus and the ulna were measured. The radiocapitellar joint pressure was measured using a pressure sensor. The tension within the interosseous membrane was measured using a custom-made strain gauge. After radial head arthroplasty, the radial head was displaced approximately 1.8 mm medially and 1.4 mm distally at the starting point. During unloaded flexion motion the difference in all translations between the native radial head and the radial head arthroplasty was less than 1 mm (95% confidence interval [CI] ± 0.5 mm) (p = 0.001). With loading the difference was less than 1.5 mm (95% CI ± 1.5 mm) (p = 0.001). The mean difference in radiocapitellar joint contact pressure was less than 0.30 MPa (95% CI ± 0.40 MPa) (p = 0.001) during unloaded flexion motion. There were only submillimetre kinematic changes and small changes in joint pressure and interosseous membrane tension after the insertion of a radial head arthroplasty in an experimental setting. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:510–522, 2020     

Excision of the Radial Head for Closed Fracture

Two-thirds of 12 patients reviewed at least 13 years after excision of the radial head for closed fracture had a good or fair result; poor results followed a delay of more than 6 weeks before operation. Less than half the patients admitted to significant elbow symptoms, although all but one had radiographic degenerative changes. All the patients except one had measurable radiographic inferior radio-ulnar subluxation, which averaged 2.3 mm, but this gave symptoms in only one case. The majority of patients can expect an acceptable clinical result from this procedure provided that certain conditions are met.     

Wear of the Polyethylene Head of the Oscobal Prosthesis

Ten hemiarthroplasties were performed with the Oscobal (Daubenspeck) hip prosthesis, which consists of a metal stem and a non-rotating polyethylene head. Five patients died 1-150 days after the operation. Signs of massive wear of the polyethylene head were demonstrated in four out of the five patients still alive 16-28 months after the operation. We can therefore not recommend the Oscobal system for hemiarthroplasty of the hip.     

Wear of the Polyethylene Head of the Oscobal Prosthesis

Ten hemiarthroplasties were performed with the Oscobal (Daubenspeck) hip prosthesis, which consists of a metal stem and a non-rotating polyethylene head. Five patients died 1-150 days after the operation. Signs of massive wear of the polyethylene head were demonstrated in four out of the five patients still alive 16-28 months after the operation. We can therefore not recommend the Oscobal system for hemiarthroplasty of the hip.     

桡骨头骨折的手术治疗

目的评价桡骨头骨折切开复位微型钢板螺钉内固定的临床效果。方法应用微型钢板螺钉治疗桡骨头骨折21例，术后将肘关节伸直位前臂中立位固定5～10d。结果术后随访6．5个月。21例患者中19例骨折愈合，平均愈合时间10周。肘关节活动好，无活动痛。2例骨折未愈合，1例行单纯桡骨头切除术，1例行假体置换术。结论就目前随访结果分析，切开复位微型钢板螺钉固定治疗桡骨头骨折，愈合率高，肘关节功能优良。该方法操作简单，易于掌握，是一种桡骨头骨折理想的治疗方法。     

Relative Head Size Increase Using an Anatomic Dual Mobility Hip Prosthesis Compared to Traditional Hip Arthroplasty: Impact on Hip Stability

Smaller head sizes and head/cup ratios make cups smaller than 50 mm and larger than 58 mm, more prone to dislocation. Using computer modeling, we compared average head sizes and posterior horizontal dislocation distance (PHDD) in two 78-patient matched cohorts. Cup sizes were small (≤ 50 mm) or large (≥ 58 mm). The control cohort had conventional fixed bearing prostheses, while the experimental cohort had anatomical dual mobility (ADM) hip prostheses. ADM cups have larger average head sizes and PHDD than traditional fixed bearing prostheses by 11.5 mm and 80% for cups ≤ 50 mm, and 16.3 mm and 90% for cups ≥ 58 mm. Larger head sizes and increased head/cup ratio may allow the ADM prosthesis to reduce the incidence of dislocation.     

人工桡骨头置换治疗桡骨头粉碎性骨折

目的探讨应用单极人工桡骨头假体置换治疗MasonⅢ、Ⅳ型桡骨头骨折的疗效。方法对15例MasonⅢ、Ⅳ型桡骨头骨折患者应用人工桡骨头假体进行置换并观察疗效。结果 15例均获随访,时间6～30个月。按Mayo肘关节功能评分评定：优9例,良5例,可1例。无感染发生。结论桡骨头在稳定肘关节及上尺桡关节中起着至关重要的作用,桡骨头骨折如不能修复,假体置换是更好的选择。