Serum Metal Ion Levels in Cementless Metal-On-Metal Total Hip Arthroplasty: Long-Term Follow-Up Trends.

BACKGROUND: Long-term trends in serum metal ion concentration after metal-on-metal (MoM) total hip arthroplasty (THA) are unclear. In most studies, serum metal ion levels increase initially and remain constant during follow-up. However, there are no previous studies that evaluate the metal ion level longitudinally at multiple intervals over the long term. Increasing metal ion levels during the long-term follow-up of patients who underwent cementless MoM THA has been seen, so this study investigated those trends. METHODS: Seventy-one patients were followed for a minimum of 10 years (range, 10.0-18.6 years). All underwent unilateral THA with MoM bearings. Serum cobalt (Co) and chromium (Cr) levels were measured preoperatively and annually after surgery. Trends and differences in serum levels based on sex, mean age, body mass index, cup inclination, and implant selection were analyzed. RESULTS: Within 5 years after the operation, the mean Co and Cr levels peaked postoperatively at 3-4 years (4.14 and 6.89 µg/L, respectively). Between 5 and 10 years postoperatively, the serum levels showed 2 tendencies. One group (62) showed a constant range, but a smaller group (9) showed increasing serum metal ion levels. The only factor which showed a difference between the 2 groups was body mass index (P = .030), which was lower in the increasing serum metal ion level group. CONCLUSION: At a medium-term to long-term follow-up period, serum Co and Cr levels are not always constant. This should be considered when seeing patients with MoM THA, and laboratory tests may be needed for long-term follow-up.

What is the Prevalence of Radiographic Hip Findings Associated With Femoroacetabular Impingement in Asymptomatic Asian Volunteers?

BACKGROUND: Morphologic features of the proximal femur reminiscent of those seen in patients with femoroacetabular impingement (FAI) have been reported among asymptomatic individuals in Western populations, but whether this is the case in Asian populations is unknown. QUESTIONS/PURPOSES: The purpose of this study was to determine the prevalence of radiographic findings in the proximal femur that are consistent with FAI in asymptomatic Korean volunteers. METHODS: Two hundred asymptomatic volunteers with no prior hip surgery or childhood hip problems underwent three-view plain radiographs (pelvis AP view, Sugioka view, and 45° Dunn view) of both hips. There were 146 hips from male volunteers and 254 hips from female volunteers in the study. The mean age of all participants was 34.7 years (range, 21-49 years). Cam-type morphologic features were defined as the presence of the following on one or more of the three views: pistol-grip morphologic features, an osseous bump at the femoral head-neck junction, flattening of the femoral head-neck offset, or alpha angle greater than 55°. Pincer-type morphologic features were determined by radiographic signs, including crossover sign, deficient posterior wall sign, or lateral center-edge angle greater than 40°. RESULTS: The prevalence of cam-type morphologic features seen on at least one radiograph was 38% (male, 57%; female, 26%). The prevalence of cam-type features (at least one positive cam-type feature) was 2.0% (male, 6%; female, 0%) on the pelvic AP view, 24% (male, 36%; female, 17%) on the Sugioka view, and 30% (male, 47%; female, 20%) on the 45° Dunn view. The prevalence of pincer-type morphologic features (at least one positive pincer-type feature) was 23% (male, 27%; female, 21%) on the pelvic AP view. CONCLUSION: The prevalence of FAI-related morphologic features in asymptomatic Asian populations was comparable to the prevalence in Western populations. Considering the high prevalence of radiographic hip findings reminiscent of FAI in asymptomatic Asian populations, it will be important to determine whether FAI-related morphologic features are a cause of hip pain when considering surgery in Asian patients.

Prevalence of radiologic acetabular dysplasia in asymptomatic Asian volunteers.

The purpose of this study was to evaluate the prevalence of acetabular dysplasia in an asymptomatic Asian population as one of the most important risk factors of hip osteoarthritis. From December 2014 to March 2015, we investigated the data of 200 asymptomatic volunteers (400 hips) aged 18-50 years recruited from our institution. Pelvic radiographs were taken and reviewed by two experienced orthopaedic surgeons. Lateral centre-edge (LCE) angle, Sharp angle, Tonnis angle and acetabular depth-to-width ratio (AD/WR) were measured. We investigated the mean values and identified the statistical differences between the sexes and evaluated the prevalence and bilaterality of acetabular dysplasia defined by each parameter. Mean LCE angle, Sharp angle, Tonnis angle and AD/WR were 26.2°, 41.3°, 8.5° and 0.28, respectively. All parameters showed more dysplastic results in females than in males and were statistically significantly different, except for AD/WR. When defined acetabular dysplasia as LCE angle <20°, Sharp angle >45°, Tonnis angle >14° or AD/WR <0.25, the prevalence of acetabular dysplasia by each parameter was 15.0%, 12.8%, 13.3% and 12.8%, respectively. There was a higher prevalence in females than in males; however, only Sharp and Tonnis angles showed significant differences. The bilaterality of acetabular dysplasia was 18.6-39.5% for all subjects. There is high prevalence of asymptomatic dysplastic hips in the Asian population.

Arthroscopic Excision of a Solitary Acetabular Osteochondroma in an Adult: A Case Report.

CASE: A 43-year-old woman presented with localized pain of the right hip 2 months after a trivial trauma. Physical examination revealed a positive Patrick (FABER [Flexion, Abduction, and External Rotation]) test. Radiographs showed a radiopaque lesion at the acetabular fossa, and magnetic resonance imaging revealed a mass with adjacent bone marrow edema. Arthroscopic excision of the lesion was performed; histopathologic examination demonstrated that it was an osteochondroma. CONCLUSION: A solitary intra-articular osteochondroma is a possible cause of localized hip pain. Hip arthroscopy can be a good diagnostic and therapeutic option.

Cobalt Intoxication Heart Failure after Revision Total Hip Replacement for Ceramic Head Fracture: A Case Report.

In 1960s, toxic heart failure due to cobalt poisoning was firstly reported from Canadian industrial worker. Following development of bearing materials in hip arthroplasties, using cobalt-chrome alloy in bearing surface, there were rarely reported of systemic affect toxic cobaltism include toxic heart failure due to articulation wear in Western countries. It could be happened more easily by third body wear from ceramic particle especially revision total hip replacement (THR) surgery using cobalt-chrome alloy following ceramic articulation breakage which index surgery performed by ceramic on ceramic bearing. In Korea, due to many surgeons prefer ceramic on ceramic bearing in THR compared to Western countries, it might be more important issue within a time. However in our knowledge, there was no previous report about cobalt poisoning heart failure in Korea. It is still very rare and hard to diagnose cobalt intoxication heart failure after THR, so we report a case of fatal heart failure caused by cobalt intoxication after revision THR in 53-year old man who successfully underwent re-revision THR.

Subarachnoid Hemorrhage Misdiagnosed as an Acute ST Elevation Myocardial Infarction.

Without significant coronary artery stenosis, ischemic electrocardiographic change including ST segment elevation, segmental wall motion abnormality and elevated serum cardiac-specific markers (creatine kinase-MB, Troponin-T) may develop after central nervous system injuries such as subarachnoid, intracranial or subdural hemorrhage. Misdiagnosing these patients as acute myocardial infarction may result in catastrophic outcomes. By reporting a case of a 55-year old female with subarachnoid hemorrhage mimicking acute ST elevation myocardial infarction, we hope to underline that careful attention of neurologic abnormality is critical in making better prognosis.