3D-printed titanium alloy cage in anterior and lateral lumbar interbody fusion for degenerative lumbar spine disease.

Background: The most commonly used cages for intervertebral disc replacement in lumbar fusion procedures are made predominantly from polyetheretherketone (PEEK). There is sufficient data studying their subsidence and failure rates from a variety of approaches. A novel implant is now available for commercial use, 3D-printed porous titanium (3DppTi) alloy cages, which have recently become available for use in spinal procedures. They have been shown in ovine models to have superior efficacy and fusion rates compared to traditional cages. However, there is limited data on their use in clinical practice and long-term outcomes associated with them. Methods: A retrospective chart review was performed, of all patients in a single institution who underwent lumbar spine fusion surgery via an anterior or lateral approach with a 3D-printed titanium alloy cage, between January 2020 and February 2021. Clinic letters, imaging and operation reports were independently reviewed to assess for fusion, or evidence of subsidence on follow-up. Results: Fifty patients were identified as meeting inclusion criteria, with a total of 66 operative levels. Of these operative levels, 32 were via an anterior approach and 34 via a lateral approach. One patient demonstrated a Marchi grade 0 subsidence, with recurrence of radiculopathy 2 months after an anterior approach, requiring posterior decompression and stabilization. A second patient demonstrated a Marchi grade 1 subsidence after a lateral approach, but did not require further surgery as they were asymptomatic at 2 years of follow-up. This study demonstrated an overall subsidence rate of 3.03%. There was a median follow-up time of 11.3 months for all patients. Conclusions: 3D-printed titanium alloy cages demonstrate a lower subsidence rate compared to historically published rates for alternative intervertebral cages, in anterior and lateral lumbar spine fusion surgery.

Alexis retractor efficacy in transthoracic thoracoscopically assisted discectomy for thoracic disc herniations.

PURPOSE: A transthoracic anterior or lateral approach for giant thoracic disc herniations is a complex operation which requires optimal exposure and maximal visualisation. Traditional metal rigid retractors may inflict significant skin trauma especially with prolonged operative use and limit the working angles of endoscopic instrumentation at depth. We pioneer the use of the Alexis retractor in transthoracic thoracoscopically assisted discectomy for the first time. METHODS: The authors describe and demonstrate the technical use of the Alexis retractor during operative cases. Patient positioning, clinical rationale and operative nuances are elucidated for readers to gain an appreciation of the transthoracic approach to thoracic disc herniations. RESULTS: The advantages of the Alexis retractor include minimally invasive circumferential flexible retraction, facilitation of bimanual instrument use, diminished risk of surgical site infections and reduced rib retraction leading to less postoperative pain. CONCLUSION: Use of the flexible and intuitive Alexis retractor maximises operative exposure and is an effective adjunct when performing complex transthoracic approaches for thoracic disc herniations.

Survival outcomes of intracranial extraventricular neurocytomas: a systematic review and individual patient data meta-analysis.

OBJECTIVE: The rarity of intracranial extraventricular neurocytomas (EVNs) has precluded accurate definition of its surgical characteristics to date. The authors present the first survival analysis of this unique entity that aims to clarify tumor characteristics, surgical outcomes, and efficacy of postoperative adjuvant therapy. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Searches of the MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Database of Systematic Reviews databases were performed from inception to date. Primary outcomes were progression-free survival (PFS) and overall survival (OS). Prognostic variables were age, sex, tumor consistency, extent of resection, and receipt of postoperative adjuvant therapy. Survival data were analyzed using Kaplan-Meier survival curves and the log-rank test to compare dichotomized cohorts. Multivariate Cox regression models were constructed, interrogated with Schoenfeld residuals, and subsequently utilized to identify independent prognostic factors. Risk of bias was assessed with the Mayo Clinic instrument. RESULTS: Five hundred fourteen articles were initially retrieved, which was distilled to 10 included articles consisting of 101 cases of intracranial EVNs. The 5-year OS rate was 90.4% (95% CI 81.8%-99.8%) and the PFS rate was 48.6% (95% CI 34.46%-68.8%). The median PFS was 60 months. Patients younger than 50 years of age experienced superior OS (p = 0.03) and PFS (p < 0.01). Gross-total resection (GTR) was superior to subtotal resection (STR) in reducing mortality (p < 0.01). Adjuvant therapy following either STR or GTR did not significantly improve survival. CONCLUSIONS: Intracranial EVNs are rare tumors that portend a poorer prognosis than central neurocytomas, despite both being WHO grade 2 tumors. Complete surgical extirpation is the cornerstone of management. There is no clearly established role for adjuvant postoperative therapy, but each case should be managed on an individual basis.

Lateral Epicondylitis Debridement and Repair Using Knotless Suture Anchor.

Lateral epicondylitis, or tennis elbow, involves degeneration of the extensor carpi radialis brevis tendon and is often self-limiting, with surgery reserved for recalcitrant cases. Surgical management of tennis elbow consists primarily of either debridement alone or debridement with repair. Surgical repair is often performed using either a suture or a suture anchor. Good outcomes have been reported using standard repair methods; however, complications exist. Complications include potential loss of grip strength with debridement alone, as well as soft-tissue irritation caused by a prominent suture or knot stack after suture repair and suture anchor techniques. We describe a technique for debridement and repair of the extensor carpi radialis brevis tendon to the lateral epicondyle of the humerus using a knotless suture anchor, allowing for a watertight anatomic repair, maximum preservation of grip strength, and absence of a knot stack and resultant suture prominence.

Experimental Constraints on Abiotic Formation of Tubules and Other Proposed Biological Structures in Subsurface Volcanic Glass.

Formation of microtubules in volcanic glass from subsurface environments has been widely attributed to in situ activity of micro-organisms, but evidence directly linking those structures to biological processes remains lacking. Investigations into the alternative possibility of abiotic tubule formation have been limited. A laboratory experiment was conducted to examine whether moderate-temperature hydrothermal alteration of basaltic glass by seawater would produce structures similar to those ascribed to biological processes. Shards of glass were reacted with artificial seawater at 150°C for 48 days. Following reaction, the shards were uniformly covered with a brick-red alteration rind 10-30 µm thick composed primarily of phyllosilicates. Inspection of the margins of reacted shards with light microscopy did not reveal any tubule structures. However, the alteration products did include features containing micron-sized spheroidal structures that resemble granular alteration textures, which some investigators have attributed to biological activity. This result suggests that the granular textures may be at least partially abiotic, and that biological activity may make a smaller contribution to alteration of the oceanic crust than has been previously proposed. Also, while the experimental results do not exclude the possibility that tubules form abiotically, they do place limitations on the conditions under which this may occur.

Long-term follow-up for keystone design perforator island flap for closure of myelomeningocele.

PURPOSE: We have previously reported a small series on the closure of large myelomeningocele (MMC) defects with a keystone design perforator island flap (KDPIF) in a paediatric neurosurgical centre in Australia. We are now presenting an updated longer term follow-up of an expanded series demonstrating longer term durability of this vascularized flap for large myelomeningocele defects. METHODS: The prospective data from the Monash Neurosurgical Database were used to select all cases of MMC between December 2008 and September 2016. Retrospective analysis of the neurosurgical database revealed an additional three patients who underwent KDPIF closure at the Monash Medical Centre for MMC repair at birth. RESULTS: Wound healing was satisfactory in all six cases. With delayed follow-up, there was no associated skin flap separation, skin flap dehiscence, skin flap necrosis, cerebro-spinal fluid leak, however two infections were encountered, both resolved with conservative management including antibiotics and simple washout. CONCLUSION: In this expanded case series with increased longevity of follow-up, the keystone design perforator island flap remains a robust alternative for closure of large myelomeningocele defects.

Safety and effectiveness of endovascular embolization or stent-graft reconstruction for treatment of acute carotid blowout syndrome in patients with head and neck cancer: Case series and systematic review of observational studies.

BACKGROUND: Indications for treatment and outcomes after endovascular management of carotid blowout syndrome for patients with head and neck cancer are not well defined. We investigated the safety and effectiveness of endovascular embolization and stent-graft reconstruction. METHODS: A literature review was performed for studies published between 2001 and 2015 with relevance to treatment outcomes. Our institutional database was examined to identify patients treated with endovascular techniques. RESULTS: A total of 266 patients were included. Rates of procedural stroke were higher after embolization of internal carotid artery (ICA)/common carotid artery (CCA) compared to stent graft (embolization 10.3%; stent graft 2.5%; P < .02). Stent graft of ICA/CCA was associated with higher rates of recurrent bleeding (embolization 9.1%; stent graft 31.9%; P < .01). CONCLUSION: Both embolization and stent grafts are safe therapeutic options for acute carotid blowout syndrome. Embolization for ICA/CCA carotid blowout syndrome was associated with higher risks of procedural stroke and lower recurrent bleeding compared to stent grafts.

Feasibility of Real-Time Angiographic Perfusion Imaging in the Treatment of Cerebral Vasospasm.

BACKGROUND: Objective assessment and quantification of the severity of cerebral vasospasm following aneurysmal subarachnoid hemorrhage is not routinely utilized. We investigated the feasibility of angiographic perfusion imaging derived from digital subtraction angiography (DSA) following endovascular vasospasm treatment procedures. METHODOLOGY: Real-time blood flow analysis was performed using parametric color coding on pre- and postintervention DSA. Semiquantitative parenchymal perfusion parameters (arrival time [AT] of contrast, time to peak [TTP] opacification, and mean transit time [MTT] of contrast) were calculated across 3 vascular territories (anterior cerebral artery [ACA], middle cerebral artery [MCA], and lenticulostriate arteries) using standard 2-D angiographic perfusion software. The pre- and postintervention arterial vessel diameters were compared. RESULTS: Twelve endovascular vasospasm treatments in 6 patients were performed. All patients received intra-arterial vasodilator therapy with either nimodipine, milrinone, or both. Following intra-arterial intervention, parenchymal flow analysis showed improvement in TTP and MTT across all vascular territories (p < 0.002) and improvement in AT in the ACA and MCA territories (p < 0.03). Improvement in parenchymal perfusion parameters was associated with improvement in vessel diameters in all territories following treatment (p < 0.05). CONCLUSION: Real-time parenchymal perfusion imaging during endovascular vasospasm treatment procedures is feasible and provides reliable semiquantitative measurement of angiographic treatment response.

Adenoid Cystic Carcinoma Presenting as Abducens Nerve Palsy Secondary to Cavernous Sinus Lesion.

BACKGROUND: We report a 61-year-old who presented with a right-sided abducens nerve palsy secondary to a middle cranial fossa adenoid cystic carcinoma (ACC) extending into the cavernous sinus. PURPOSE: This case represents a unique presentation of intracranial ACC with a large middle cranial fossa mass and only a small extracranial component. METHODS: Review of the literature was undertaken to identify cases of intracranial ACC and their range of presentations. RESULTS: Our results show that this is the first reported case of an ACC presenting mostly as an intracranial mass with an isolated cranial nerve lesion. CONCLUSION: Our case highlights the importance of a broad differential diagnosis, particularly in circumstances where there are atypical features of lesions on radiographic imaging.

Obstructive Hydrocephalus Secondary to Enlarged Virchow-Robin Spaces: A Rare Cause of Pulsatile Tinnitus.

BACKGROUND: Obstructive hydrocephalus secondary to enlarged Virchow-Robin Spaces (VRS) is a rare entity, with only a few cases reported in the literature. Presenting symptoms vary widely from headaches to dizziness. CASE DESCRIPTION: We report a case of a 31-year-old man who presented with pulsatile tinnitus and magnetic resonance imaging showing obstructive hydrocephalus secondary to tumefactive VRS. After a cerebrospinal fluid diversion procedure in the form of an endoscopic third ventriculostomy, he had almost complete resolution of his symptoms. CONCLUSIONS: This is the first case of obstructive hydrocephalus secondary to enlarged VRS, presenting with pulsatile tinnitus.

Generation of Hydrogen and Methane during Experimental Low-Temperature Reaction of Ultramafic Rocks with Water.

UNLABELLED: Serpentinization of ultramafic rocks is widely recognized as a source of molecular hydrogen (H2) and methane (CH4) to support microbial activity, but the extent and rates of formation of these compounds in low-temperature, near-surface environments are poorly understood. Laboratory experiments were conducted to examine the production of H2 and CH4 during low-temperature reaction of water with ultramafic rocks and minerals. Experiments were performed by heating olivine or harzburgite with aqueous solutions at 90°C for up to 213 days in glass bottles sealed with butyl rubber stoppers. Although H2 and CH4 increased steadily throughout the experiments, the levels were very similar to those found in mineral-free controls, indicating that the rubber stoppers were the predominant source of these compounds. Levels of H2 above background were observed only during the first few days of reaction of harzburgite when CO2 was added to the headspace, with no detectable production of H2 or CH4 above background during further heating of the harzburgite or in experiments with other mineral reactants. Consequently, our results indicate that production of H2 and CH4 during low-temperature alteration of ultramafic rocks may be much more limited than some recent experimental studies have suggested. We also found no evidence to support a recent report suggesting that spinels in ultramafic rocks may stimulate H2 production. While secondary silicates were observed to precipitate during the experiments, formation of these deposits was dominated by Si released by dissolution of the glass bottles, and reaction of the primary silicate minerals appeared to be very limited. While use of glass bottles and rubber stoppers has become commonplace in experiments intended to study processes that occur during serpentinization of ultramafic rocks at low temperatures, the high levels of H2, CH4, and SiO2 released during heating indicate that these reactor materials are unsuitable for this purpose. KEY WORDS: Serpentinization-Hydrogen generation-Abiotic methane synthesis. Astrobiology 16, 389-406.

Cerebral arterial angioplasty in a patient with Loeys-Dietz syndrome.

A 14-year-old boy with Loeys-Dietz syndrome (LDS) had an acute neurologic decline 6 days after a subarachnoid hemorrhage. Cerebral angiography at presentation did not show an aneurysmal source of the hemorrhage. However, on post-bleed day 6 the patient experienced an acutely worsening headache and subsequently lost consciousness. Head CT showed new subarachnoid blood and repeat angiography demonstrated a basilar tip aneurysm. Endovascular coil embolization was performed and his neurologic status improved postoperatively until post-bleed day 9 when he became unresponsive. A CT angiogram demonstrated severe proximal vasospasm. After an unsuccessful attempt to treat the vasospasm medically, the patient was transported to the neurointerventional suite for intra-arterial vasodilator treatment, which also failed to ameliorate the vasospasm. The endovascular surgeons were then faced with the conundrum of attempting a high-risk cerebral angioplasty in a pediatric patient with LDS or returning to maximal medical treatment for severe refractory vasospasm.

Cerebral arterial angioplasty in a patient with Loeys-Dietz syndrome.

A 14-year-old boy with Loeys-Dietz syndrome (LDS) had an acute neurologic decline 6 days after a subarachnoid hemorrhage. Cerebral angiography at presentation did not show an aneurysmal source of the hemorrhage. However, on post-bleed day 6 the patient experienced an acutely worsening headache and subsequently lost consciousness. Head CT showed new subarachnoid blood and repeat angiography demonstrated a basilar tip aneurysm. Endovascular coil embolization was performed and his neurologic status improved postoperatively until post-bleed day 9 when he became unresponsive. A CT angiogram demonstrated severe proximal vasospasm. After an unsuccessful attempt to treat the vasospasm medically, the patient was transported to the neurointerventional suite for intra-arterial vasodilator treatment, which also failed to ameliorate the vasospasm. The endovascular surgeons were then faced with the conundrum of attempting a high-risk cerebral angioplasty in a pediatric patient with LDS or returning to maximal medical treatment for severe refractory vasospasm.

Heterotopic bone formation about the hip undergoes endochondral ossification: a rabbit model.

BACKGROUND: Heterotopic ossification (HO) occurs most commonly after trauma and surgery about the hip and may compromise subsequent function. Currently available animal models describing the cellular progression of HO are based on exogenous osteogenic induction agents and may not reflect the processes following trauma. QUESTIONS/PURPOSES: We therefore sought to characterize the histologic progression of heterotopic bone formation in an animal model that recapitulates the human condition without the addition of exogenous osteogenic material. METHODS: We used a rabbit model that included intramedullary instrumentation of the upper femur and ischemic crush injury of the gluteal muscle. Bilateral surgical induction procedures were performed on 30 animals with the intention of inciting the process of HO; no supplemental osteogenic stimulants were used. Three animals were sacrificed at each of 10 predetermined times between 1 day and 26 weeks postoperatively and the progression of tissue maturation was graded histologically using a five-item scale. RESULTS: Heterotopic bone reliably formed de novo and consistently followed a pathway of endochondral ossification. Chondroid elements were found in juxtaposition with immature woven bone in all sections that contained mature osseous elements. CONCLUSIONS: These results establish that HO occurs in an animal model mimicking the human condition following surgical trauma about the hip; it is predictable in its histologic progression and follows a pathway of endochondral bone formation. CLINICAL RELEVANCE: By showing a consistent pathway of endochondral ossification leading to ectopic bone formation, this study provides a basis for understanding the mechanisms by which HO might be mitigated by interventions.

Time from ACL injury to reconstruction and the prevalence of additional intra-articular pathology: is patient age an important factor?

PURPOSE: Meniscus and cartilage lesions have been reported to be prevalent during delayed reconstruction of anterior cruciate ligament (ACL) injuries. Relatively, little work has been done exploring the influence of patient age on this relationship. The purpose of this study is to determine whether the effect of time from ACL injury to reconstruction on the prevalence of associated meniscal and chondral injury is influenced by patient age. It was hypothesized that patients in whom the time from ACL injury to reconstruction exceeds 12 weeks will exhibit an increased prevalence of medial compartment pathology relative to those reconstructed within 12 weeks of injury in patients of all ages. METHODS: Data detailing time from ACL injury to reconstruction and the prevalence of intra-articular findings were obtained in 311 of 489 consecutive patients undergoing primary isolated ACL reconstruction. Patients were divided into two groups based on whether the time from ACL injury to reconstruction was <12 weeks or at least 12 weeks. The prevalence of associated intra-articular injury was then compared between the two groups. Patients were then stratified based on age (22 years and under vs. over the age of 22), and the analysis was repeated on both groups. RESULTS: Analysis of all patients together revealed a significantly higher prevalence of medial meniscus injury (p = 0.013) and medial compartment chondral injury (p < 0.0005) in patients in whom the time from ACL injury to reconstruction exceeded 12 weeks. The prevalence of lateral meniscal injury did not increase with increasing time ACL injury to surgery. Among patients aged 22 years and under, there was no increase in the prevalence of intra-articular pathology in any compartment in the late reconstruction group. In contrast, among patients over the age of 22, there was a significant increase in the prevalence of medial chondral injury (p = 0.042) in the late reconstruction group. CONCLUSION: The prevalence of injuries to the meniscus and articular cartilage in the medial compartment of the knee is increased with increasing time from ACL injury to reconstruction. This relationship may vary depending on patient age. Patients over the age of 22 exhibit a higher prevalence of intra-articular injury with delayed reconstruction, while no such differences are noted among younger patients. LEVEL OF EVIDENCE: Retrospective comparative study, level III.

Arthroscopic suture anchor capsulorrhaphy versus labral-based suture capsulorrhaphy in a cadaveric model.

PURPOSE: The purpose of this study was to establish whether suture anchor capsulorrhaphy (SAC) is biomechanically superior to suture capsulorrhaphy (SC) in the management of recurrent anterior shoulder instability without a labral avulsion. METHODS: Twelve matched pairs of shoulders were randomized to either SC or SAC. Specimens were mounted in 60° of abduction and 90° of external rotation. Testing was conducted on an MTS servohydraulic load testing device (MTS, Eden Prairie, MN). A compressive load of 22 N was applied, followed by a 2-N anterior and posterior force to establish a 0 point. Translation with 10-N anterior and posterior loads was recorded for baseline laxity measurement. Arthroscopic capsulorrhaphy was performed with either 3 solitary sutures or 3 suture anchors. Specimens were remounted and returned to the 0 point. Translation was measured with 10-N anterior and posterior loads to determine reduction in translation. Specimens were then loaded to failure to the 0 point at a rate of 0.1 mm/s. RESULTS: Load to failure was significantly greater (P = .02) in the SC group (13.6 ± 1.0 N) versus the SAC group (20.5 ± 2.8 N). No differences were found between SC (2.7 ± 0.7 mm) and SAC (2.3 ± 0.6 mm) when we compared reduction of anterior translation with a 10-N load. The percent reduction of anterior displacement with a 10-N load was similar for the SC (49.9%) and SAC (49.6%) groups. The dominant mode of failure in the study was suture pull-through of the capsular tissue. CONCLUSIONS: Our study indicates that labral-based SC and SAC similarly reduce anterior glenohumeral translation at low loading conditions. Load-to-failure studies indicate that SAC exhibits significantly greater resistance to translation at higher loading conditions. Our study suggests that the use of a suture anchor when one is performing a capsulorrhaphy may provide biomechanical advantage at high loading conditions. CLINICAL RELEVANCE: Our study suggests that when one is performing capsulorrhaphy, the use of a suture anchor may provide biomechanical advantages at high loading conditions.

Surgical techniques and outcomes after anterior cruciate ligament reconstruction in preadolescent patients.

PURPOSE: To determine whether any anterior cruciate ligament (ACL) reconstruction technique is clinically superior in skeletally immature patients with wide-open physes. METHODS: We searched Medline and Embase from 1966 to mid July 2009. Inclusion criteria required clinical studies of ACL reconstructions to define skeletally immature patients as having at least 1 of the following criteria: (1) chronologic age of less than 15 years in boys or less than 14 years in girls; (2) bone age of less than 15 years in boys or less than 14 years in girls; (3) Tanner stage I, II, or III; and (4) at least 10 cm of total growth after the reconstruction. Thirteen case series were identified and were evaluated for patient characteristics, surgical technique, clinical outcomes, and bone growth results. RESULTS: Four studies used physeal-sparing techniques. Six studies used transphyseal techniques. Two studies used a combined technique, and a multicenter study reported results of both techniques. Within the physeal-sparing group, there were 2 studies that used an entirely extra-epiphyseal technique and 2 studies that used intra-epiphyseal techniques. Overall clinical outcomes were excellent, with growth complications being very rare in all of these series. CONCLUSIONS: Both physeal-sparing and transphyseal reconstructions can produce excellent clinical outcomes with a very low incidence of growth complications in Tanner stage II and III patients. Tanner stage I patients had excellent clinical results with physeal-sparing techniques (both extra- and intra-epiphyseal techniques). Not enough Tanner stage I patients underwent transphyseal techniques to support or discourage their use. This evidence supports considering the expansion of transphyseal reconstruction indications from Tanner stage IV patients to Tanner stage II and III patients. More studies evaluating transphyseal techniques in Tanner stage I patients are needed at this time. LEVEL OF EVIDENCE: Level IV, systematic review.

Treatment of chronic glenoid defects in the setting of recurrent anterior shoulder instability: a systematic review.

OBJECTIVE: The purpose is to systematically evaluate the literature regarding treatment of chronic glenoid bone defects in the setting of recurrent anterior shoulder instability to determine if, from an evidence-based outcomes approach, one technique may be recommended over the other. METHODS: PubMed 1966-2009, Embase 1980-2009, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials databases were searched for human studies in English. Keywords were osseous glenoid defects, glenoid bone grafting, Latarjet procedure, iliac crest and glenoid defects, and glenoid rim fractures. Inclusion criteria were all articles evaluating chronic glenoid deficiency in the setting of recurrent anterior glenohumeral instability. Exclusion criteria were surgical techniques not reporting follow-up, glenoid rim fractures treated by open reduction internal fixation, and investigations not quantifying glenoid deficiency assessments. RESULTS: Six articles met all inclusion and exclusion criteria. All articles were level IV (case series), most (5/6) were retrospective. Multiple techniques involving coracoid transfer and allograft or autograft reconstruction have been described for management of chronic glenoid deficiency. Lack of high level evidence in the form of prospective randomized trials limits our ability to recommend one technique over another. The 6 techniques reviewed here were all effective at preventing recurrent instability. CONCLUSIONS: Chronic glenoid deficiency in the setting of recurrent anterior instability is an extremely challenging problem. There remains a lack of strong evidence guiding the surgeon in the decision-making process. Additional research is needed to optimize the preoperative glenoid defect assessment, further evaluate the reconstruction techniques, and follow the long-term effects of reconstruction on the development of glenohumeral arthrosis.

The Mark Coventry Award: Prevention of readmission for venous thromboembolism after total knee arthroplasty.

Venous thromboembolism is the most common reason for readmission after total knee arthroplasty. Prospective contrast venography was conducted from 1984 to 2003 in 1321 patients undergoing total knee arthroplasty. Patients with deep venous thrombosis or pulmonary embolism were treated with warfarin; those with negative venograms received no further anticoagulation. From 1984 to 1992, patients not completing venography were discharged without warfarin; since 1993 patients without venography received warfarin for 6 weeks. Readmission for deep venous thrombosis, pulmonary embolism, or bleeding was tracked for 6 months. Venography was completed in 810 patients; 343 (42.3%) had deep venous thrombosis. Readmission for venous thromboembolism occurred in 0.6% of patients after total knee compared with 1.62% after total hip arthroplasty. Following total knee arthroplasty, patients discharged on warfarin (target INR 2.0) had a 0.21% readmission rate compared with 1.05% for patients with negative venograms discharged without further anticoagulation. One patient suffered a fatal pulmonary embolism after negative venography and no outpatient prophylaxis. Secondary prophylaxis with extended warfarin therapy reduced venous thromboembolism-related readmission. Surveillance venograms were a poor predictor of ultimate thromboembolism risk and need for extended anticoagulation therapy. We therefore recommend extended warfarin prophylaxis for all patients after hospital discharge following total knee arthroplasty.

The John Charnley Award: prevention of readmission for venous thromboembolic disease after total hip arthroplasty.

UNLABELLED: Venous thromboembolic disease remains the most common reason for readmission after total hip arthroplasty. Prospective analysis of screening contrast venography was done from 1984 to 2003 in 1972 patients having elective total hip arthroplasty. Patients with deep venous thrombosis or pulmonary embolism received warfarin therapy; those with negative venograms received no further anticoagulation. From 1984 to 1992, patients not completing venography were discharged without warfarin; since 1993, patients without venography received warfarin for 6 weeks. Readmission for deep venous thrombosis, pulmonary embolism, or bleeding was tracked for 6 months. Venograms were completed in 1032 patients; 175 (16.9%) had deep venous thrombosis. Deep venous thrombosis was reduced by a clinical pathway that included continuous epidural anesthesia (14.2% versus 22.5%). The overall readmission rate for venous thromboembolic disease was 1.62%, including 14 pulmonary emboli (three fatal) and 18 femoral deep venous thrombosis. Readmission occurred in 0.27% (1 of 360) patients on continued warfarin, compared with 2.2% (19 of 880) with negative venograms discharged without further anticoagulation. Three patients (0.15%) suffered fatal pulmonary emboli; all had negative venograms and received no outpatient prophylaxis. Extended outpatient warfarin therapy provided effective protection against venous thromboembolic disease readmission. Surveillance venography was a poor predictor of need for continued prophylaxis; all patients should have extended anticoagulation after total hip arthroplasty. LEVEL OF EVIDENCE: Therapeutic study, Level I-1 (high-quality randomized trial with statistically significant difference or no statistically significant difference but narrow confidence intervals). See the Guidelines for Authors for a complete description of levels of evidence.