Articulating Spacers in Total Hip Arthroplasty: Surgical Technique and Outcomes

Although one-stage exchange arthroplasty is gaining popularity, two-stage exchange arthroplasty remains the gold standard for the treatment of periprosthetic joint infections. Use of an articulating spacer for this procedure offers an avenue for maintaining hip motion and controlled weight-bearing, allowing local antibiotic elution. However, there is no uniform consensus on the optimal surgical protocol for using articulating spacers. This review describes the surgical technique for undertaking a first-stage exchange arthroplasty using an articulating spacer and discusses the pertinent literature on key concepts relating to periprosthetic joint infections in total hip arthroplasty to guide effective surgical decision making in these patients.

Periprosthetic Fractures After a Total Knee Arthroplasty

As the number of total knee arthroplasties performed continues to increase, complications such as postoperative periprosthetic fractures are becoming increasingly more common. Femoral periprosthetic fractures are the most common type of fractures around a total knee arthroplasty, whereas tibial and patellar periprosthetic fractures are infrequent. Treatment principles depend on the bone the fracture is located, the status of the implant fixation, bone stock, and the type of implants available. The Vancouver classification allows for a standardized system to describe and manage these injuries, incorporating these factors. A systematic approach is vital in obtaining the best possible outcomes because complications and mortality rates mimic those of hip fractures.

Malseating of Modular Dual Mobility Liners: High Prevalence in Revision Total Hip Arthroplasty

BACKGROUND

Modular dual mobility (MDM) acetabular components have become increasingly more popular in total hip arthroplasty (THA). Uncertainty remains regarding liner malseating and its consequences after 5 to 10 years, especially in patients who undergo revision THA. The objective of this study was to analyze the prevalence of malseating and implant survivorship of patients who underwent revision THA using an MDM liner.

METHODS

We retrospectively identified patients who had a minimum 2-year follow-up and underwent revision THA using an MDM liner. Patient demographics, implant details, mortality, and all-cause revisions were recorded. Patients who had radiographic follow-up were assessed for malseating. Kaplan Meier survival was used to determine implant survivorship. We included 143 hips in 141 patients. Mean age was 70 years (35 - 93 years) and 86 patients (60.1%) were female.

RESULTS

Overall implant survival was 89.3% (95% Confidence Interval (CI) 0.843 - 0.946) at a mean follow-up of 6 years (range 2 to 10) years. There were eight patients excluded from malseating assessment. Upon radiological review, 15 liners (11.1%) were malseated. Survival for all-cause revision for patients with malseated liners was 80.0% (12/15, 95% CI 0.62 - 0.99, P= 0.15) versus 91.5% in patients who had non-malseated liners (110/120, 95% CI 0.86 - 0.96). There were no intraprosthetic dislocations and 3.5% of the patients were revised due to instability. No liners were revised due to malseating, and no patients who had malseated liners were revised due to instability.

CONCLUSIONS

Using MDM components in our cohort comprised of revision THA was associated with a high prevalence of malseating and an overall survival of 89.3% at a mean follow up of 6 years. Malseating does not appear to impact implant survival at a mean follow-up of 6 years.

Highly crosslinked polyethylene liner thickness does not influence survival in primary total hip arthroplasty after mean follow-up of 13 years: a study of 2,565 hips with a single design liner

BACKGROUND

Concerns remain that thinner highly crosslinked polyethylene (HXLPE) liners in modern total hip arthroplasty (THA) may lead to premature liner-related failures or revision. The aim of this study was to evaluate the effect of liner-thickness on survival and revision rates of HXLPE in primary THA after more than 10 years.

METHODS

We retrospectively identified 2,565 primary THA using HXLPE with a mean follow-up of 13 years (range, 11 to 19). Patients were grouped for each millimeter (mm) of polyethylene thickness. Liner thickness varied from 4.9 to 12.7 mm, with one third measuring less than 6 mm. Primary outcomes were reoperation, all-cause revision, and liner-related revision.

RESULTS

The reoperation rate was 7.3%, the all-cause revision rate was 5.6%, and the liner-related revision rate was 0.04%. There was no significant difference in all-cause revision when stratified by liner thickness (P=0.286) and liner thickness was not associated with liner-related revision (n=1). There was a statistically, but not clinically significant difference in mean liner thickness for the cohort that underwent reoperation (7.09 vs 6.89 mm, P=0.01) and all-cause revision (7.16 vs 6.89 mm, P=0.031).

CONCLUSION

In our cohort, liner thickness was not associated with all-cause revision-free survival and there was no clinically significant difference in liner thickness between those patients who did require a reoperation or all-cause revision, and those who did not. There was only 1 liner related failure in the entire cohort. Our results indicate that using thinner HXPE liners to maximize femoral head size in THA is a safe practice that does not lead to increased revision rates or liner failure at a mean 13 years follow-up.

The management of fracture related infections: What practices can be supported by high-level evidence?

Fracture related infections (FRIs) are a disabling condition causing significant concern within the orthopaedic community. FRIs have a huge societal and economic burden leading to prolonged recovery times and the potential for becoming chronic conditions or being life-threatening. Despite its importance in our field, the surgical community has just recently agreed on a definition which, added to the lack of surgical trials assessing preventive and treatment interventions have limited our understanding and precipitated wide variations in surgeons' practice. This article aims to review the current practices that can be supported with high-quality evidence. Currently, we have a limited body of high-quality evidence on FRI prevention and treatment. A handful of measures have proven effective, such as the use of prophylactic antibiotics, the use of saline and low pressure as the preferred irrigation solution and the safety of delaying initial surgical débridement more than 6 hours without impacting infection rates for open fracture wounds débridement. Future multicentre trials, properly powered, will shed light on current areas of controversy regarding the benefit of different preoperative and perioperative factors for the prevention and treatment of FRIs. Higher quality evidence is needed to guide surgeons to offer an evidence-based approach to prevent FRI occurrence and to treat patients suffering from them.

Chronic Pseudoaneurysm and Anterior Dislocation After Total Hip Arthroplasty Complicated by Arterial Injury: A Case Report

CASE

A 64-year-old man presented 18 months after total hip arthroplasty complicated by vascular injury with a history of leg pain, inability to mobilize, and progressive chronic leg edema. It is presumed that there was persistent subtle bleeding over time with pseudoaneurysm formation and prosthetic hip dislocation secondary to the mass effect.

CONCLUSION

Physicians should consider pseudoaneurysm as a possible diagnosis when confronted with a large intra-articular mass in the hip after a relatively short follow-up period, particularly in the context of a prior vascular injury at the time of the index procedure.

The influence of the CT scan in the evaluation and treatment of nondisplaced femoral neck fractures in the elderly

BACKGROUND

The management of nondisplaced femoral neck fractures (FNFs) has evolved, with emphasis in radiographic features such as posterior displacement. However, the role of advanced imaging in this scenario is still not well defined. Therefore, our objective is to assess the impact of a computed tomography scan (CT) on interobserver agreement (IA) of fracture classification, posterior tilt measurement, and treatment decisions in nondisplaced FNF in elderly patients.

METHODS

Eleven patients with a nondisplaced (Garden 1-2) FNF were assessed by six hip surgeons. On a first stage, fracture classification, posterior tilt, and treatment plan (fixation/arthroplasty) were determined only with clinical information and X-rays. On a second stage, a CT was added. The kappa coefficient ( κ) and intraclass correlation coefficient (ICC) were used to determine IA.

RESULTS

IA for Garden classification was only slight in X-rays and with the addition of a CT, with a κ = 0.13 (0-0.28) and 0.18 (0.03-0.33), respectively. Conversely, posterior tilt measurement agreement was excellent in both schemes, with an ICC = 0.92 (0.83-0.98) and 0.92 (0.82-0.98). The IA for the proposed treatment was slight with X-rays ( κ = 0.44; 0.29-0.6), but moderate with the addition of a CT scan ( κ = 0.67; 0.52-0.82). Changes in surgical decision where made in 14 of 66 evaluations with an OR = 1.4 (0.62-3.2) for choosing an arthroplasty if a CT was used.

CONCLUSION

IA for fracture classification and posterior tilt evaluation in nondisplaced FNF was not altered by the usage of a CT. There is improvement in treatment agreement when a CT scan is added to conventional imaging, with changes in treatment in 21% of cases.

[Management of hip fractures in the elderly. A national survey among Chilean orthopaedic surgeons]

BACKGROUND

As the population ages, patients exposed to osteoporotic fractures increase, especially hip fracture, which is the most severe and costly.

AIM

To characterize surgical practices in the management of hip fractures in older patients through a nationwide survey of specialized hip surgeons dedicated to the care of these patients.

MATERIAL AND METHODS

A survey composed of 32 questions was formulated, including demographic factors, preoperative evaluation, definitive treatment, and postoperative management. It was sent to 140 specialists. 84 of them replied (61%), and 71 answers were included.

RESULTS

Eighty six percent of respondents agreed that orthogeriatric management is fundamental in the outcome of these patients, but only 73% had the collaboration of an internist or a geriatrician. Although 97% considered 72 hours or less the ideal time to perform surgery, only 52% of the respondents declared performing surgery within that timeframe, with differences between private and public system. Regarding surgical treatment, 94-98% of femoral neck fractures are treated with an arthroplasty and 98-99% of per-subtrochanteric fractures are treated with internal fixation and osteosynthesis. Osteoporosis treatment is only carried out by 51% of the respondents and with significant variation.

CONCLUSIONS

This survey shows that there is agreement in surgical practice between specialists treating these patients, but clear differences in preoperative optimization, treatment timeframe, and post fracture medical treatment.

[Perioperative care of older patients with hip fractures]

The number of osteoporotic fractures is increasing along with population aging. Most patients with these type of fractures are older than 65 years, with multiple chronic conditions and different degrees of disability. Hip fracture is the most relevant osteoporotic fracture due to its frequency, costs, severity and complications. Multidisciplinary management is of the utmost importance to obtain good therapeutic results. We herein review the management of this fracture. Orthogeriatric joint management should be incorporated in fragility fracture treatment. We contribute with general recommendations for the perioperative management, which can be homologated for the management of older patients with other type of fragility fractures.

Efficacy of MR Angiography in the Detection and Characterization of Occlusive Disease in the Vertebrobasilar System

PURPOSE

The purpose of this work was to determine the efficacy of MR angiography (MRA) in the detection and characterization of occlusive disease in the vertebrobasilar system.

METHOD

We retrospectively reviewed the posterior circulation registry of our institution to select 42 consecutive patients with posterior circulation ischemic symptoms who underwent both MRA and angiography. The extracranial vertebral arteries (ECVAs) were examined by two-dimensional time-of-flight MRA above the C6 level, and the intracranial vertebral arteries (ICVAs) and basilar arteries (BAs) were examined by three-dimensional time-of-flight MRA. Sixty-two ECVAs, 63 ICVAs, and 39 BAs were examined by the readers.

RESULTS

Occlusive disease was seen on angiography in 22 of the 42 patients. The sensitivity and specificity values for detection of lesions in 12 ECVA, 19 ICVA, and 12 BA abnormalities were as follows: ECVA, 92 and 96% for Reader A and 100 and 90% for Reader B; ICVA, 84 and 93% for Reader A and 74 and 82% for Reader B; and BA, 100 and 88% for Reader A and 100 and 78% for Reader B. For ICVA, the sensitivity of MRA was less than that of angiography because of lesions missed by the readers at the junctional area of the extra-and intracranial MRA. MRA accurately characterized 9 of the 12 (75%) ECVA, 10 of the 19 (43%) ICVA, and 11 of the 12 (92%) BA lesions.

CONCLUSION

MRA is an effective method for detection of occlusive lesions in the ECVAs and BAs. Clinically important lesions can be missed by MRA in the ICVA. MRA is more accurate in characterization of occlusive lesions in BAs than in ECVAs or ICVAs.

Two groups of TH-like immunoreactive neurons in the frog (Rana pipiens) retina

The morphology and distribution of TH-like immunoreactive (TH-IR) cells in the retina of Rana pipiens were studied in retinal whole mounts and in radial and horizontal sections. A large majority (96%) of the immunoreactive cells were found in the inner nuclear layer while a few cells were found in the ganglion cell layer. All TH-IR cells had round to oval somata with average diameter of 10 microm. The 2-4 primary processes of these cells distributed extensively to sublamina 1 of the inner plexiform layer (IPL) and sparsely to sublamina 5. Two groups of TH-IR cells were distinguished: one, designated thin cells, had only thin (<2 microm diameter) primary processes; the second, designated thick cells, had one or more primary processes with diameter(s) exceeding 2 microm for a distance of 5 microm or more from the soma. The thin cells did not significantly differ from the thick cells in soma diameter, number of primary processes, horizontal spread of processes or vertical lamination of processes. Nearest neighbor analyses of the two types revealed that the population of TH-IR cells (thick and thin together) have an orderly distribution while the thick cells alone are more randomly distributed, indicating that the thick cells do not comprise a functional population. The total number of TH-IR cells varied between retinas; the variability was due principally to variation of thin cell density. It is hypothesized that the thick cells are a subpopulation of the TH-IR cells which are in a particular physiological state at the time of fixation.