Altered activity of pain processing brain regions in association with hip osteoarthritis

Hip osteoarthritis (OA) is characterized by chronic pain, but there remains a mismatch between symptoms and radiological findings. Recently, brain connectivity has been implicated in the modulation of chronic peripheral pain, however its association with perceived pain in hip OA is not understood. We used resting-state functional magnetic resonance imaging (fMRI) to examine functional connectivity associated with pain in hip OA patients. Thirty participants with hip OA and 10 non-OA controls were recruited. Using the visual analogue scale (VAS), pain scores were obtained before and after performing a painful hip activity. All participants underwent 3.0 T resting-state fMRI, and functional connectivity of brain regions associated with pain was determined and compared between participants, and before and after hip activity. Relative to controls, functional connectivity between the secondary somatosensory cortex and left posterior insula was increased, and functional connectivity between the bilateral posterior insula and motor cortices was significantly decreased in hip OA participants. In response to painful hip activity, functional connectivity increased between the thalamus, periaqueductal grey matter and brainstem. Functional connections between brain regions associated with pain are altered in hip OA patients, and several connections are modulated by performing painful activity. Unique lateralization of left posterior insula and linked brain functional connectivity patterns allows assessment of pain perception in hip OA providing an unbiased method to evaluate pain perception and pain modulation strategies.

Remote transient Lactobacillus animalis bacteremia causing prosthetic hip joint infection: a case report

Background

Lactobacillus spp. are uncommon pathogens in immunocompetent hosts, and even rarer causes of prosthetic device infections.

Case presentation

A case of chronic hip prosthetic joint infection (PJI) caused by L. animalis is described. This occurred 5 years after a transient bacteremia with the same organism. Whole genome sequencing of both isolates proved this PJI infection resulted from this remote bacteremia.

Conclusions

We document that prosthetic joint infections may be a consequence of bacteremia as much as 3 years before the onset of symptoms.

Subcapital osteotomy of the femoral neck for patients with healed slipped capital femoral epiphysis

We report the clinical and radiological outcome of subcapital osteotomy of the femoral neck in the management of symptomatic femoroacetabular impingement (FAI) resulting from a healed slipped capital femoral epiphysis (SCFE). We believe this is only the second such study in the literature.

We studied eight patients (eight hips) with symptomatic FAI after a moderate to severe healed SCFE. There were six male and two female patients, with a mean age of 17.8 years (13 to 29).

All patients underwent a subcapital intracapsular osteotomy of the femoral neck after surgical hip dislocation and creation of an extended retinacular soft-tissue flap. The mean follow-up was 41 months (20 to 84). Clinical assessment included measurement of range of movement, Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis score (WOMAC). Radiological assessment included pre- and post-operative calculation of the anterior slip angle (ASA) and lateral slip angle (LSA), the anterior offset angle (AOA) and centre head–trochanteric distance (CTD). The mean HHS at final follow-up was 92.5 (85 to 100), and the mean WOMAC scores for pain, stiffness and function were 1.3 (0 to 4), 1.4 (0 to 6) and 3.6 (0 to 19) respectively. There was a statistically significant improvement in all the radiological measurements post-operatively. The mean ASA improved from 36.6° (29° to 44°) to 10.3° (5° to 17°) (p <  0.01). The mean LSA improved from 36.6° (31° to 43°) to 15.4° (8° to 21°) (p < 0.01). The mean AOA decreased from 64.4° (50° to 78°) 32.0° (25° to 39°) post-operatively (p < 0.01). The mean CTD improved from -8.2 mm (-13.8 to +3.1) to +2.8 mm (-7.6 to +11.0) (p < 0.01). Two patients underwent further surgery for nonunion. No patient suffered avascular necrosis of the femoral head.

Subcapital osteotomy for patients with a healed SCFE is more challenging than subcapital re-orientation in those with an acute or sub-acute SCFE and an open physis. An effective correction of the deformity, however, can be achieved with relief of symptoms related to impingement.

Cite this article: Bone Joint J 2014;96-B:1441–8.

An ORS-ICP-MS method for monitoring trace levels of cobalt and chromium in whole blood samples from hip arthroplasty patients with metal-on-metal prostheses

OBJECTIVE

To develop a rapid and reliable method, using an octopole reaction system (ORS) ICP-MS, capable of monitoring trace levels of Co and Cr in whole blood samples from hip arthroplasty patients with metal-on-metal prostheses.

DESIGN AND METHOD

Whole blood is diluted 10-fold with an alkaline diluent and analyzed using an Agilent 7500 CE ORS-ICP-MS.

RESULTS

Limit of quantification of 0.03 μg/L Co and 0.20 μg/L Cr in patient samples. <6% covariance obtained for quality control materials analyzed over 10 runs.

CONCLUSION

This method is capable of monitoring trace levels of Co and Cr in diluted whole blood samples with a vial to vial run time of approximately 2 min. Results are comparable to those obtained using high resolution (HR) ICP-MS with sample digestion.

Surgical dislocation of the hip for the fixation of acetabular fractures

Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9).

Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports.

Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis.

Intracapsular fracture of the proximal femur fracture after hip resurfacing treated by cannulated screws

Fracture of the neck of the femur after resurfacing arthroplasty usually leads to failure and conversion to a total hip replacement. We describe an intracapsular fracture of the femoral neck sustained after hip resurfacing which was treated by cannulated screws, resulting in union and retention of the resurfacing implant. The result at follow-up three years later was very satisfactory with a Harris hip score of 99.

The effect of a venous filter on the embolic load during medullary canal pressurization: a canine study

BACKGROUND

Acute intramedullary stabilization of femoral shaft fractures in multiply injured patients is controversial. Intravasation of medullary fat during canal pressurization has been suspected to trigger adult respiratory distress syndrome. The goal of the present study was to evaluate the effect, on the lungs, of a filter placed into the ipsilateral common iliac vein during medullary canal pressurization in a canine model.

METHODS

With use of an established model of fat embolization, twelve mongrel dogs were randomized into two groups. In six dogs, a special filter was inserted percutaneously into the left common iliac vein while the dogs were under general anesthesia. In all dogs, the left femur and tibia were then pressurized by injection of bone cement and insertion of intramedullary rods. Hemodynamic measurements and echocardiographic images were recorded throughout the experiment. After one hour, the animals were killed and the lungs were harvested for histomorphometric analysis.

RESULTS

Without the filter, the mean pulmonary artery pressure increased by 11.8 +/- 2.1 mm Hg (p < 0.001). With the filter, the mean pulmonary artery pressure increased by only 2.2 +/- 0.8 mm Hg (p < 0.02). Without the filter, there was a significant increase in the index of pulmonary vascular resistance as compared with the baseline value (p < 0.05). With the filter, there was no such increase. Histomorphometric analysis demonstrated that the presence of the filter reduced the absolute area of embolization and the volume percentages of lung and pulmonary vasculature embolized.

CONCLUSIONS

In this canine experiment, temporary placement of a venous filter prior to medullary canal pressurization reduced the embolic load and minimized its hemodynamic effects.

Non-union of acetabular fractures

Non-unions of acetabulum are rare. Seven cases of acetabular non-unions are reported in this retrospective study. Five out of our seven patients had either transverse or associated transverse with posterior wall fractures. All patients had surgical stabilisation of their index fractures. A diagnosis of non-union was made at an average of 5.8 months from the original injury based on clinical and radiological features. Five of the six patients who underwent re-stabilisation and bone grafting of the non-union healed where as the remaining one did not heal after two attempts at re-stabilisation and was treated with excision arthroplasty. Two of the healed five, subsequently developed osteoarthritis and had total hip arthroplasty where as one patient had already developed degeneration of his hip at the time of diagnosis and hence treated with total hip arthroplasty. Analysis of the non-unions confirmed that fixation was unstable in all with residual displacement seen in two of them. In conclusion acetabular fracture non-union appear to be associated with transverse fractures and unstable fixation.

Assessment of osteoporosis using standard radiographs of the wrist

BACKGROUND

This study evaluated the ability of the orthopaedic surgeon to radiographically assess bone density in the wrist with sufficient accuracy to determine which patients require treatment for osteoporosis.

METHODS

Thirty-eight patients with unilateral distal radius fractures, 30 of whom were female, were included in this study. The mean age was 55 years (range 45 to 82). Standard radiographs of the fractured and normal wrists were taken. Dual energy x-ray absorptiometry was performed on the normal distal radius of all patients within 1 week of their injury. The radiographs were viewed in blinded randomized fashion on two separate occasions by three orthopaedic surgeons and once by a fourth. The participants were required to determine the presence of osteoporosis. Visual analog scales (VAS) were used to evaluate (1) porosity, (2) cortical thickness, (3) trabecular thickness, and (4) the number of trabeculae in the ultradistal radius.

RESULTS

Intraobserver agreement assessing osteoporosis averaged 81% (kappa of 0.5393). VAS assessment was unreliable for all four parameters. Radiographic determination of osteoporosis had a specificity of 61% and a sensitivity of 61% using x-rays of the uninjured wrist.

CONCLUSION

We conclude that orthopaedic surgeons cannot predict with sufficient accuracy using plain x-rays whether a patient is significantly osteoporotic.

The effect of comorbidity and duration of nonunion on outcome after surgical treatment for nonunion of the humerus

The purpose of our study was to assess the effect of comorbidity and duration of nonunion on the general health status and joint-specific outcome of a group of patients treated for nonunion of the humeral shaft. We identified 25 consecutive patients with nonunion of the humeral shaft, all treated with compression plating and bone grafting. Twenty-one patients returned for a comprehensive assessment including completion of the SF 36 Health Status Survey and determination of the Constant shoulder and Morrey elbow scores. Thirteen patients had > or = 1 comorbid conditions. Eleven patients had a nonunion of > 8 months' duration, and 10 had a nonunion of < 8 months' duration. Follow-up at a mean of 42 months (range 12 to 99 months) revealed that all nonunions united an average of 5 months after surgery. The mean Morrey elbow score was 94, Constant shoulder score 82, and "global" SF 36 score 59.4. The physical portion of the SF 36 score correlated well with the Constant and Morrey scores (p = 0.047 and p = 0.027, respectively). The presence of comorbid factors had a significant negative effect on the SF 36 scores (p = 0.001) but no effect on joint-specific Morrey or Constant scores. The duration of nonunion had no effect on SF 36 or joint-specific scores. Although the reliability of the SF 36 is illustrated by the close correlation between its "physical function" portion and standard (joint-specific) outcome measures, comorbidity has a significant negative effect on overall scores. This must be considered when such tools are used for assessment of orthopaedic intervention.

Evaluation of pelvic fractures. Clinical and radiologic

This article gives the orthopedic surgeon a framework to use during the initial evaluation of a patient with a pelvic fracture in the emergency room. The essential elements of the assessment of instability, both clinically and radiologically, are given in this article. Examples of the major patterns of instability are provided.

Open pelvic fractures. A multicenter retrospective analysis

A marked discrepancy exists in the reported mortality rates in patients with open pelvic fractures, ranging from 4.8% to 50%. A retrospective review of patients with open pelvic fractures was performed at three centers. Thirty-nine patients with open pelvic fractures were identified; the average age was 32. The average injury-severity score was 29 (13-75). There were 10 (26%) deaths. Factors that correlated with mortality and morbidity were instability of the pelvic fracture and the presence of a rectal injury. Delay in performing diverting colostomy correlated with a poor outcome. Previously described methods of treatment are still valid; however, there is a need for re-emphasis of early diverting colostomy in the patient with a rectal or perineal injury. A classification system for open pelvic fractures is proposed in this article.

Fixation of segmental subtrochanteric fractures. A biomechanical study

Segmental subtrochanteric fractures have been associated with high rates of malunion, nonunion, and implant failure. Although the use of second generation intramedullary nails with proximal interlocking in the femoral head has been advocated for these fractures, shaft fractures at the tip of short second generation intramedullary rod nails in clinical studies raise concerns about the mechanical suitability of these implants. No biomechanical data are available on the strength of fixation and mode of failure of these newer implants. This study compares the strength and failure mode of segmental subtrochanteric fractures stabilized with 3 current implants. Eighteen anatomic specimen femurs were obtained. The 3 implants tested were the Russell-Taylor reconstruction nail, a short intramedullary hip screw, and a long intramedullary hip screw. Each femur was instrumented and a segmental subtrochanteric fracture was created. The femurs were loaded in a Materials Testing System. The strength of the reconstruction nail group (2869 +/- 210 N) was significantly greater than for the short intramedullary rod hip screw (2330 +/- 490 N), and the long intramedullary rod hip screw (2181 +/- 244 N). The failure modes for the implants were: screw cut out of the femoral head for the reconstruction nail; fracture of the femoral shaft for the short intramedullary hip screw, and implant bending for the long intramedullary hip screw. This study suggests that the reconstruction nail is the superior implant for segmental subtrochanteric fractures of those tested. Implant bending and shaft fractures at lower loads make the 2 intramedullary rod hip screw implants less suitable.

Small versus large diameter closed-section femoral nails for the treatment of femoral shaft fractures: is there a difference?

A retrospective series of 99 femoral shaft fractures treated by small diameter (10 and 11 mm) and large diameter (> 11 mm) closed section femoral nails from November 1989 to September 1993 was analyzed. No significant differences in the parameters of bony union and time to full weight bearing were seen between the two groups nor were there significant differences between the rate of secondary procedures. There were no broken nails in either group and there was no difference in the overall respiratory complication rate.

CONCLUSION

No statistically significant differences existed between the small and large diameter groups except for the mean age and mean follow-up period. Small diameter nails can be used safely without the risk of nail breakage.

Lateral extension of the ilioinguinal incision in the operative treatment of acetabulum fractures

The choice of which decision to use for open reduction and internal fixation of complex acetabulum fractures depends on several variables. We report on 26 patients in whom a lateral extension of the ilioinguinal incision was used to achieve fracture reduction and stabilization. The lateral extension allowed visualization of the lateral ilium, in some cases passage of cerclage wires around the anterior and posterior columns, and in some cases placement of lateral to medial lag screws above the dome of the acetabulum. Reduction with a step of 1 mm or less and a gap of 3 mm or less with joint congruence was achieved in 21 patients (81 per cent). No patients had clinically significant heterotopic ossification. One patient had a transient postoperative femoral neuropathy, one a superficial infection, and one a deep infection. We recommend this lateral extension as an option during surgery of complex acetabular fractures through the ilioinguinal incision.

Comparison of torsional strength of humeral intramedullary nailing: a cadaveric study

Control of rotation after intramedullary fixation of the humeral shaft has been observed to vary clinically. Two of the newer intramedullary nails specifically designed for the humerus were tested. Transverse and spiral fractures were created in 35 fresh-frozen cadaveric humeri. The constructs were tested in a materials testing system to evaluate in vitro the torsional strength of the nailed humeral fractures. Intact bones showed a mean peak torque of 53 +/- 17 Nm. The humeri fixed with the Russell-Taylor nail (n = 18) using one interlocking screw proximally and one distally showed a mean torsional strength of 10.4 +/- 3.6 Nm. The specimens fixed with the Seidel nail (n = 17), interlocked proximally with two screws and distally by the friction of three expanded flanges against the inner cortex, had a significantly lower mean torsional strength of 1.5 +/- 0.6 Nm (p < 0.0005). When compared with intact bones, constructs using the Russell-Taylor nail achieved 20% of mean peak torque. This improved rotational strength should permit an earlier return to full functional use of the extremity.

Multiple-level noncontiguous spinal fractures

Double-level noncontiguous spinal injury is a more common occurrence than generally appreciated. A large number of these patients have neurological injury. Because these injuries occur in patients who meet the criteria for categorization as multiple trauma patients, we feel that a complete radiographic survey of the spine must be accomplished in the emergency room in any situation where clinical assessment is impaired. Treatment must be individualized with the same guidelines for treatment as for the isolated injury in the majority of circumstances.

Biodegradable resurfacing of the hip in dogs

Arthroplasties of the hips in dogs using a biodegradable poly-L-lactide cup to protect the regenerating cartilage following removal of normal articular cartilage and the drilling of multiple full thickness defects into subchondral bone were performed to determine whether or not the repair response could be improved. The poly-L-lactide cup degraded in approximately 60 days. The regenerating cartilage was much better in the experimental than the control dogs initially, but ultimately failed, perhaps due to inadequate duration of protection of the immature cartilage by the arthroplasty material.

The induction of chromosomal abnormalities by inhalational anaesthetics

When Vicia faba root tips are exposed for 2 h to clinically useful concentrations of halothane or methoxyflurane in air, or to halothane in 80% nitrous oxide/20% oxygen, there is a transient increase in mitotic index and then abnormal interphase cells are produced in proportion to the anaesthetic concentrations. After exposure there is a period of mitotic inhibition during which the cells become partially synchronised. When colchicine-metaphase cells collected 28 h after exposure are compared with controls and with metaphases collected only 4 h after exposure, they show a significant increase in the incidence of aneuploidy, tetraploidy and the results of chromosome breakage. It is suggested that all the abnormalities seen can be accounted for by the effects of the anaesthetics on spindle movements, and that at the concentrations used the anaesthetics have no mutagenic effects on chromosomes in interphase.