Bilateral Mechanically-Assisted Crevice Corrosion Resulting in Femoral Stem-Head Dissociation in Metal-on-Polyethylene Total Hip Arthroplasty

There are emerging reports of complications related to corrosion in modular femoral components. We report a unique case describing an 83-year-old man with bilateral mechanically-assisted crevice corrosion in hip replacements performed 10 years previously, by the same surgeon using the same size 3 Accolade TMZF stem and same 44-mm CoCr LFIT V40 head (Stryker Orthopedics, Mahwah NJ). Our patient presented with complete femoral stem-head complex dissociation of his right hip and elevated serum cobalt and chromium levels. He subsequently underwent right hip revision arthroplasty while his contralateral hip is monitored closely as an outpatient. This case helps to define the poorly understood mechanisms and component design factors implicated in this emerging issue. We also hope to provoke discussions about guidelines for monitoring and revising failing metal-on-polyethylene arthroplasty systems.

Purple urine bag syndrome: a case report and review of the literature

Purple urine bag syndrome (PUBS) is a rare and striking manifestation associated with urinary tract infection involving bright purple discoloration of the lining and tubing of a urinary catheter bag. We present the interesting case of a 90-year-old female patient who developed PUBS and include a review of the relevant literature to date. Uniquely, in this case, PUBS acts as an important clinical sign in supporting the diagnosis of urinary tract infection in a high-risk patient.

Radiological outcomes of distal radius extra-articular fragility fractures treated with extra-focal kirschner wires

INTRODUCTION

The classical colles fracture (extra-articular, dorsally angulated distal radius fracture) in patients with osteoporotic bone is becoming increasingly more frequent. There still appears to be no clear consensus on the most appropriate surgical management of these injuries. The purpose of this study is to appraise the use of percutaneous extra-focal pinning, in the management of the classical colles fracture.

METHODS

We retrospectively analysed 72 consecutive cases of colles fractures treated with inter-fragmentary k-wire fixation, in female patients over 60 years of age, in two orthopaedic centres, under the care of 12 different orthopaedic surgeons. We correlated the radiographical distal radius measurements (ulnar variance, volar tilt, and radial inclination) at the pre-operative and intra-operative stages with the final radiographical outcome.

RESULT

Mean dorsal angulation was 21 degrees at time of presentation. Closed reduction significantly improved fracture position to a mean of 2.7 degrees volar angulation (p<0.05). Mean angulation at time of k-wire removal was 1.6 degrees dorsal, this was not significant in comparison to post-reduction measurements (p<0.05). Mean ulnar variance at time of presentation was 2.5mm (range 7.4 to -4.2). Reduction improved fracture displacement to a mean of 0mm, which was statistically significant (p<0.05). Mean ulnar variance at time of k-wire removal was 2.4mm (p<0.05). 56.8% of cases demonstrated radial shortening of 2mm or more.

CONCLUSION

In female patients over 60 years of age, the best predictor of radial length, when k-wire fixation is to be used, is the radial length prior to fracture reduction. Thus if there is radial shortening visible in the initial radiographs as measured in terms of ulnar variance, one should consider a method of fixation other than inter-fragmentary k-wires.

Magnetic resonance imaging of bone bruising in the acutely injured knee—short-term outcome

AIM

To investigate the short-term outcome and associated injuries of bone bruising in the acutely injured knee.

METHOD AND MATERIALS

Thirty patients (age range 17-39 years, mean 28 years) with bone bruising identified on magnetic resonance imaging (MRI) after an acute knee injury were rescanned 12-14 weeks post-injury. The volume of bone bruising was measured on coronal STIR (short TI inversion recovery) images and correlation made with the presence and type of ligamentous and osteochondral injuries.

RESULTS

All bone bruises were present on repeat MRI. Twenty of the 30 patients (67%) had associated anterior cruciate ligament (ACL) injuries, seven of the 30 (23%) had collateral ligament injuries and three of the 30 (10%) had no associated ligamentous injuries. Greater than 50% reduction in bone bruise volume was demonstrated at repeat scanning in 24 of the 30 patients (80%) and less than 50% in five of the 30 patients (17%). One patient showed an increase in volume of bone bruising at follow-up. There was no correlation between initial size or size reduction of bone bruising and the presence/absence or type of associated injuries. In 21 patients the bone bruises resolved from the periphery, whilst eight patients showed bone bruises that resolved towards the joint margin, all of whom had associated osteochondral injuries. Of the 30 patients, 17 showed bone bruising that extended to the joint margin, 10 of whom had associated osteochondral injuries on MRI. On clinical review some degree of knee pain was still present in all but one of the patients reviewed. The single patient who reported complete resolution of symptoms was one of the three patients with isolated bone bruising.

CONCLUSION

Bone bruises persist for at least 12-14 weeks, which is longer than previously quoted. Two discrete patterns of bone bruise resolution have been demonstrated. The size and persistence of bone bruising is not related to the presence or absence or type of associated ligamentous injuries.

Spina bifida occulta in isthmic spondylolisthesis: a surgical trap

An 11-year-old girl presented with symptomatic grade IIB isthmic type spondylolisthesis, with an elongated pars, confirmed on magnetic resonance imaging (MRI). Posterolateral in situ fusion of L5/S1 was performed. At surgery, a significant bony defect in the posterior aspect of S1 was noted. Awareness of this possible co-existence is paramount if iatrogenic damage to neural elements is to be avoided during surgery.

Bizarre parosteal osteochondromatous proliferation (Nora's lesion) of the sesamoid: a case report

We report the a case of Nora's lesion (Bizarre Parosteal Osteochondromatous Proliferation) of the sesamoid. A 32-year-old woman presented with a painless, enlarging mass of two years duration on the plantar aspect of the first metatarsophalangeal joint of the left foot. Radiographs, Computerized Tomographs and Magnetic Resonance images, initially suggested a parosteal osteosarcoma arising from the tibial sesamoid. The mass was excised, and a histological diagnosis of Bizarre Parosteal Osteochondromatous Proliferation of bone (Nora's lesion) was made. The aggressive growth of this lesion may suggest a neoplasm clinically. Histological features, however, are those of a reactive lesion.