Catastrophic failure of a low profile metal-backed glenoid component after total shoulder arthroplasty

Context:

The longevity of the glenoid component in total shoulder arthroplasty (TSA) continues to be problematic. All polyethylene glenoid components have been most widely used, but loosening rates with time and the need for revision has resulted in high-profile metal-backed components with the potential for a more stable prosthesis bone interface and liner exchange. High revision rates in the high profile metal backed designs led us to evaluate a low profile metal backed component.

Aims:

To examine the rate and mode of failure of a TSA in a single surgeon consecutive series that has been identified by the Australian National Joint Replacement Registry to have a higher than anticipated rate of revision.

Materials and Methods:

This is a single surgeon retrospective consecutive series of 51 arthroplasties undertaken in 50 patients (18 males and 32 females) with an average age of 70.4 ears (range 51-90) and mean follow-up of 5.5 years (range 3.7-8.1).

Results:

We observed a very high (29%) rate of revision of the metal-backed glenoid components in this series. The primary mode of failure was glenoid baseplate nonintegration which with a well-fixed central cage screw led to bone resorption and implant breakage or disassembly.

Conclusion:

Analysis of the mode of failure of implants identified by robust registries is essential for the development of new prostheses and the pursuit of prosthesis longevity. This low profile metal backed prosthesis has been withdrawn, but without a published mechanism of failure. We feel that any prosthesis withdrawal should be accompanied by appropriate published mechanisms to prevent future component design errors based on similar design problems.     

Skull Base Approach to Carotid Artery Lesions: Technique,Indications, and Outcomes

Operative approaches to lesions of the carotid artery at the skull base are challenging and place multiple cranial nerves at risk. Herein, we describe a preauricular approach utilizing anterior dislocation of the temporomandibular joint with microscopic drill-out of the medial glenoid and Eustachian tube to identify and skeletonize the carotid artery in the foramen lacerum. The facial nerve remains undissected during this approach. Nine of 10 patients presented with aneurysm, six spontaneous and three following blunt trauma, and one patient presented with carotid artery rupture after penetrating trauma. Three of the patients presented with cranial nerve (CN) deficits that persisted. One patient was unevaluable preoperatively due to trauma but awoke with multiple CN deficits. Only one of nine evaluable patients suffered a new long-term CN deficit (XI). One patient had persistent temporomandibular joint dysfunction. All patients had long-term patency of the graft or anastamosis and no new neurologic symptoms were reported with a mean follow-up of 55 months. Open approaches to the carotid artery at the skull base are feasible and with careful anatomic dissection can be performed with minimal morbidity in most cases. We present full details and images of the operative approach.     

Glenoid cartilage mechanical properties decrease after rotator cuff tears in a rat model

Rotator cuff repairs are commonly performed to reduce pain and restore function. Tears are also treated successfully without surgical intervention; however, the effect that a torn tendon has on the glenohumeral cartilage remains unknown. Clinically, a correlation between massive rotator cuff tears and glenohumeral arthritis has often been observed. This may be due to a disruption in the balance of forces at the shoulder, resulting in migration of the humeral head and subsequently, abnormal loading of the glenoid. Our lab previously demonstrated changes in ambulation and intact tendon mechanical properties following supraspinatus and infraspinatus rotator cuff tendon tears in a rat model. Therefore, the purpose of this study was to investigate the effects of supraspinatus and infraspinatus rotator cuff tears on the glenoid cartilage. Nine rats underwent unilateral detachment of the supraspinatus and infraspinatus tendons and were sacrificed after 4 weeks. Cartilage thickness significantly decreased in the antero‐inferior region of injured shoulders. In addition, equilibrium elastic modulus significantly decreased in the center, antero‐superior, antero‐inferior, and superior regions. These results suggest that altered loading after rotator cuff injury may lead to damage to the joint with significant pain and dysfunction. Clinically, understanding the mechanical processes involved with joint damage will allow physicians to better advise patients. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1435–1439, 2012     

The latarjet procedure for recurrent anterior shoulder instability: Rationale and technique

Posterosuperior glenoid impingement (PSGI) is defined as mechanical impingement of the greater tuberosity onthe posterosuperior aspect of the glenoid rim during shoulder abduction, external rotation, and extension. Although this contact is present in most of the population, throwing athletes are particularly vulnerable to developing symptoms related to this impingement, predominantly from partial thickness tears of the rotator cuff. It has been suggested that subtle or “micro”-instability is the underlying source of this “internal” impingement. After examining these claims with regard to our experience and experience of others, this does not seem to be the case. Additionally, we report our preferred treatment regimen for PSGI including our technique for humeral derotational osteotomy.     

Laparoscopic Douglasectomy in the treatment of painful uterine retroversion

Background: One of the etiologies of pelvic pain in women, often unrecognized, is the Masters-Allen syndrome, which was described in 1955 as the ``universal joint cervix' syndrome. It has the following three elements: (1) etiology: obstetrics-related trauma; (2) clinical findings: uterine retroversion with hypermobile cervix following elongation or desinsertion of the uterosacral ligaments; (3) anatomy: visualization of a tearing of the posterior serosa and subperitoneal fascia of the ligamentum latum. Methods: Forty-one laparoscopic Douglasectomies with uterosacral ligamentopexy were performed in the department of Gynecology at the University Hospital of Caen during the period between 1990 and 1995 in patients with painful retroverted uterus. The patient selection was made thanks to the ``pessary test.' The surgical endoscopic procedure, identical to the operation first promoted by Jamain and Letessier in 1976 by laparotomy, is described. Results: Total pain relief was experienced by 31 patients (75%) and partial relief by five patients (5%). Two main complications occurred, requiring one laparotomy (bleeding from a pelvic varicose vein with a concomitantly occurring breakdown of the washing-aspiration system) and one second laparoscopy at day 15 (one case of hematoma below the peritonization revealed by pain). Twenty-three women became pregnant again, and had normal deliveries except for two cesareans, with no recurrence of pain. Douglasectomy is compared to alternative techniques in the literature. Other indications for Douglasectomy are discussed. Conclusion: Douglasectomy is the only definitive procedure for restoring normal anatomy of the pelvic floor in case of painful uterine retroversion occurring in a setting of Masters-Allen syndrome. Additionally, it provides for pathological analysis of the excised peritoneum. The results of this procedure are excellent when the indication is correctly set, particularly as concerns positive pessary testing. Received: 22 April 1996/Accepted: 15 July 1996