Femoral component neck fracture after failed hip resurfacing arthroplasty

Failure on the femoral side after third-generation metal-on-metal hip resurfacing arthroplasty is suggested to be easily treated with conversion to conventional total hip arthroplasty. Clinical results of conversion for failed hip resurfacing arthroplasty with the use of primary femoral implants confirmed this for a short-term follow-up. We present a case of the occurrence of a stemmed femoral implant neck fracture in a patient who was earlier treated for a failed hip resurfacing. We advise to consider acetabular revision in case of (suspected) acetabular metal damage and to use a stem component with a relative large neck diameter.     

Perioperative fracture-dislocation of the humeral head during a resurfacing hemiarthroplasty

We report a case of perioperative fracture-dislocation of the humeral head produced during the reaming for a resurfacing replacement hemiarthroplasty (RRH) in a 79-year old woman. This is a surgical complication not previously described in the literature for this type of prosthesis design. Resurfacing humeral head implant has been noted as a useful treatment for glenohumeral arthropathies, also in elderly people, with a very low incidence of complications. However, as we report, they are possible.It is advisable that conventional stemmed implants could be available when RRH is performed.     

Periprosthetic humeral fracture after Copeland resurfacing and the role of revision arthroplasty: A report of three cases

Follow-up series of the Copeland resurfacing hemiarthroplasty have reported few postoperative fractures around the prosthesis. We report three cases of periprosthetic fracture around a Copeland resurfacing arthroplasty. Due to prosthetic loosening and tuberosity comminution, all cases were managed with revision shoulder arthroplasty. All patients had good functional outcome and range of movement on early follow-up.     

Thermal damage during humeral reaming in total shoulder resurfacing

Introduction:

Total shoulder resurfacing (TSR) provides a reliable solution for the treatment of glenohumeral arthritis. It confers a number of advantages over traditional joint replacement with stemmed humeral components, in terms of bone preservation and improved joint kinematics. This study aimed to determine if humeral reaming instruments produce a thermal insult to subchondral bone during TSR.

Patients and Methods:

This was tested in vivo on 13 patients (8 with rheumatoid arthritis and 5 with osteoarthritis) with a single reaming system and in vitro with three different humeral reaming systems on saw bone models. Real-time infrared thermal video imaging was used to assess the temperatures generated.

Results:

Synthes (Epoca) instruments generated average temperatures of 40.7°C (SD 0.9°C) in the rheumatoid group and 56.5°C (SD 0.87°C) in the osteoarthritis group (P = 0.001). Irrigation with room temperature saline cooled the humeral head to 30°C (SD 1.2°C). Saw bone analysis generated temperatures of 58.2°C (SD 0.79°C) in the Synthes (Epoca) 59.9°C (SD 0.81°C) in Biomet (Copeland) and 58.4°C (SD 0.88°C) in the Depuy Conservative Anatomic Prosthesis (CAP) reamers (P = 0.12).

Conclusion:

Humeral reaming with power driven instruments generates considerable temperatures both in vivo and in vitro. This paper demonstrates that a significant thermal effect beyond the 47°C threshold needed to induce osteonecrosis is observed with humeral reamers, with little variation seen between manufacturers. Irrigation with room temperature saline cools the reamed bone to physiological levels and should be performed regularly during this step in TSR.     

Revision shoulder arthroplasty including bony deficiency

The shoulder is the most lax joint of the human body, and its stability is obtained by the action of the multiple surrounding structures, making surgical restoration of shoulder function a technically demanding procedure. Currently total shoulder arthroplasty has been widely accepted in the treatment of various diseases especially in rheumatoid and degenerative arthritis and fractures. As one might think, the increased number of shoulder arthroplasties has apparently led to higher revision rates, as in total hip and knee arthroplasties. The main mechanisms of failure after a primary shoulder arthroplasty are instability, component loosening, malposition, infection, and periprosthetic fracture.     

影响髋关节表面置换术后关节功能恢复的多因素分析

目的探讨影响股骨头缺血性坏死患者行髋关节表面置换术后关节功能恢复的因素。方法1997年6月至2008年7月对股骨头缺血性坏死患者45例47髋行半髋关节表面置换,男25例,女20例;年龄29—49岁,平均36．6岁。应用Harris髋关节评分对疗效进行评定。研究患者的年龄、性别、体重指数、职业、病因、Ficat分期、髋部手术史、股骨假体柄干角、术后开始锻炼时间等相关因素,在单因素分析基础上应用Logistic回归模型作多因素分析。应用SPSS13．0进行统计学分析,其中Harris髋关节评分作为因变量,分为优、较好、良、差4类,其中前2类视为功能恢复满意。结果45例患者随访1—11年,平均8．6年。Harris髋关节评分：优15例,较好20例,良8例,差2例,满意率为77．8％。单因素分析结果发现患者的体重指数、Ficat分期、股骨假体柄干角、术后开始锻炼时间4个因素与髋关节功能恢复显著相关（P〈0．05）。Logistic回归发现此4个因素是影响髋关节功能恢复的主要因素。结论体重指数、Ficat分期、股骨假体柄干角、术后锻炼时间可明显影响髋关节表面置换术后功能恢复。     

髋关节表面置换术的临床进展

髋关节疾病严重影响着患者的生活质量,尤其对于年轻、活动量大、预期寿命长、功能要求高的患者,由于传统的全髋关节置换术（total hip arthroplasty,THA）截除了正常的股骨颈而改变了生物力学关系,加上假体磨损相关并发症、股骨颈骨折等问题,使得THA术后可能需行多次翻修手术。     

Impingement and stability of total hip arthroplasty versus femoral head resurfacing using a cadaveric robotics model

We identified and compared the impingent‐free range of motion (ROM) and subluxation potential for native hip, femoral head resurfacing (FHR), and total hip arthroplasty (THA). These constructs were also compared both with and without soft tissue to elucidate the role of the soft tissue. Five fresh‐frozen bilateral hip specimens were mounted to a six‐degree of freedom robotic manipulator. Under load‐control parameters, in vivo mechanics were recreated to evaluate impingement free ROM, and the subluxation potential in two “at risk” positions for native hip, FHR, and THA. Impingement‐free ROM of the skeletonized THA was greater than FHR for the anterior subluxation position. For skeletonized posterior subluxations, stability for THA and FHR constructs were similar, while a different pattern was observed for specimens with soft tissues intact. FHR constructs were more stable than THA constructs for both anterior and posterior subluxations. When the femoral neck is intact the joint has an earlier impingement profile placing the hip at risk for subluxation. However, FHR design was shown to be more stable than THA only when soft tissues were intact. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1108–1115, 2013     

Femoral revision in hip resurfacing compared with large-bearing metal-on-metal hip arthroplasty

It has been suggested that revision of the femoral component of hip resurfacing after femoral failure would be straightforward and have an outcome comparable to primary total hip arthroplasty (THA). We have compared the outcome of femoral side-only revision resurfacings to the results of primary modular large-bearing metal-on-metal THA. Fourteen consecutive patients underwent revision surgery of the failed femoral component, to a cemented tapered stem (CPT, Zimmer, Warsaw, Indiana) with a large modular metal head (Smith and Nephew Orthopaedics Ltd, Memphis, Tennessee, or Adept, Finsbury Orthopaedics, Surrey, England). The acetabular component was found to be well fixed, well orientated, and was left in situ. The 14 matched patients in the primary THA group received the same components. At a mean follow-up of 49 months (range, 30-60 months), clinical outcome measured using the Oxford and Harris Hip Scores showed no significant difference (P = .11, P = .45, respectively). Operative time and blood loss were comparable for both groups. We conclude that revision of the failed femoral resurfacing component gives excellent results.     

A review of humeral stem removal during revision shoulder arthroplasty

Despite the overwhelming clinical success of shoulder arthroplasty, several situations may arise that necessitate revision arthroplasty. This often requires removal of the humeral component. Extraction of a humeral prosthesis is a technically demanding procedure, which requires an understanding of the indications for humeral component explantation, careful preoperative planning, knowledge of the humeral component to be removed, a grasp of several different methods of stem removal, and the tools required. Cement extraction often poses substantial technical challenges and requires further specialized instruments. Surgeons should be prepared to manage specific complications that may arise such as canal perforation and humerus fracture.