Wear Analysis of Highly Cross-Linked Polyethylene in Young and Active Patients at Average Fourteen Years: A Concise Follow-Up of a Previous Report

Background

Concerns persist regarding the oxidative stability of annealed highly cross-linked polyethylene (HXLPE) and hence its wear performance especially long term in young and active patients. The purpose of this study is to assess the wear rates and clinical outcomes of a first-generation annealed HXLPE.

Nasal dermoids — our experience

Dermoid Cysts and fistulas of the nose represent an uncommon embryological error. The frequency of misdiagnosis and recurrences of this lesion indicates the lack of awareness of its occult ramifications which lead to a compromised incomplete excision and are classified as “misadventures”, We would like to present our experience with nasal dermoids — their clinical presentation and management.     

Advanced wear of an Oxinium? femoral head implant following polyethylene liner dislocation

Oxinium^™ (Smith & Nephew, Memphis, TN, US) has been used in hip arthroplasty since 2003. The surface coating is hard and provides low wear rates but if this surface coating is damaged, the soft metal core is at risk of accelerated wear. Previous reports have described accelerated wear following intra and postoperative hip dislocation. We report a case of advanced wear of an in situ Oxinium^™ femoral head implant following a cracked acetabular liner. The liner had disengaged from the titanium shell, allowing the Oxinium^™ head to articulate directly with the shell. The disengaged liner led to dislocation of the Oxinium^™ head, with associated pronounced wear of the head and the acetabular cup. The patient had a successful revision procedure. We advise close follow-up of patients with Oxinium^™ implants, especially if associated with dislocation and closed reduction.     

Robotic guidance in total hip arthroplasty: the shape of things to come

Surgeons want to perform a perfect total hip arthroplasty (THA) with every operation. Human performance has limitations, especially when performing a mechanical operation in a biological environment. Recent suggested changes to improve outcomes have been large femoral heads and anterior incisions, but unfortunately, neither has resulted in any scientific data that change has been effected. The scientific data tell us that poor component positions and impingement are the source of increasing mechanical complications. Therefore, attempts have been made to improve the surgeon's performance by precise quantitative knowledge in the operating room. Robotic-guided navigation provides numerical data for cup inclination plus anteversion and center of rotation; femoral leg length and offset; and combined anteversion of the cup and stem. The acetabular bone preparation is done with a reamer connected to a robotic arm, which prevents human error by the surgeon of reaming off line or too deep. This technology provides predictable and reproducible results.     

Modes of failure of knotted and knotless suture anchors in an arthroscopic bankart repair model with the capsulolabral tissues intact

The purpose of this study was to assess failure modes of knotless and knotted anchors in a Bankart repair model with the capsulolabral soft tissues intact. Previous reports used a model stripped of soft tissues. In 8 matched pairs of cadaver shoulders, a Bankart lesion was repaired arthroscopically using either 2 Bio-SutureTak anchors (Arthrex, Naples, Florida) or 2 Bioknotless anchors (Mitek, Westwood, Massachusetts). The shoulders were mounted with the repaired capsulolabral tissues attached to a custom sinusoidal clamp, and were tested in cyclic loading (20-80 N, 100 cycles, 0.5 mm/s) and then load to failure (1.25 mm/s). Cut-through at the suture-tissue interface (23/32 anchors) was more common than pullout at the anchor-bone interface (9/32) as a mode of failure (P = .02). Failure at the suture-tissue interface occurred in 10/16 knotted and 13/16 knotless anchors. Mean (SD) ultimate load of knotted vs knotless anchors was 125.3 (67.4) N and 96.9 (95.1) N, respectively. Mean (SD) stiffness of knotted vs knotless anchors was 20.9 (6.4) N/mm and 19.8 (8.6)N/mm, respectively. We concluded that both knotted and knotless anchors fail most often at the suture-tissue interface. The tested model with the capsulolabral tissues intact is distinct from previous models, which tested the anchor-bone interface only.     

Radiographic Predictors of Hip Pain in Femoroacetabular Impingement

The primary diagnosis of femoroacetabular impingement is based on clinical symptoms, physical exam findings, and radiographic abnormalities. The study objective was to determine the radiographic findings that correlate with and are predictive of hip pain in femoroacetabular impingement (FAI). One hundred prospective patients with unilateral FAI symptoms based on clinical and radiographic findings were included in this study. All patients filled out a WOMAC pain questionnaire. Two independent-blinded surgeons assessed antero-posterior and lateral radiographs for 33 radiographic parameters of FAI. Correlations between pain scores and radiographic findings were calculated. A matched radiographic analysis was performed comparing symptomatic versus asymptomatic hips. Radiograph findings were also compared between males and females. Weak positive correlations were identified between increasing pain scores with radiographic findings of posterior wall dysplasia, presence of a shallow socket, and a more lateral acetabular fossa relative to the Ilioischial line. A symptomatic hip had a lower neck shaft angle, greater distance from Ilioischial line to acetabular fossa and larger distance from cross-over sign to superolateral point of the acetabulum when compared to the asymptomatic hip in the same patient. Symptomatic hips in males had more joint space narrowing, femoral osteophytes, higher alpha angles and larger, more incongruent femoral heads compared to females. Females had more medial acetabular fossa relative to the Ilioischial line and smaller femoral head extrusion index. Similar to other musculoskeletal conditions, radiographic findings of FAI are poor predictors of hip pain.     

Diagnosis and management of traumatic and atraumatic hip instability in the athletic patient

Although relatively uncommon compared with the shoulder, hip instability can be a source of significant disability and is a commonly unrecognized injury. Hip instability can be traumatic or atraumatic in origin. Our understanding and treatment plan for hip instability due to traumatic events is well established. However, our understanding and treatment modalities for hip instability due to atraumatic events or repetitive motion in high level athletes are not as well defined. In this article, we will review the spectrum of traumatic and atraumatic hip instability and discuss the relevant anatomy, history, and physical examination findings, imaging studies, and treatment options with a focus on hip arthroscopy, and review of the literature.