Arthroscopic Treatment of Osteochondral Lesions of the Talus in a Pediatric Population: A Minimum 2-Year Follow-up.

BACKGROUND: Treatment of osteochondral lesions of the talus (OLTs) in children presents a difficult clinical challenge, with few large series reported. PURPOSE: To evaluate functional and radiographic outcomes for children and adolescents undergoing arthroscopic treatment of symptomatic OLT with a minimum follow-up of 2 years. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients were identified who had symptomatic OLT treated arthroscopically with marrow stimulation techniques. Inclusion criteria were age ≤18 years, symptomatic chronic OLT as the surgical indication, failure of nonoperative treatment, and minimum follow-up of 24 months. Outcome measures included Foot Function Index, American Orthopaedic Foot and Ankle Society Hindfoot Score, Tegner Activity Scale, 36-Item Short Form Health Survey (Short Form-36, v 2), visual analog scale, ankle range of motion, and patient satisfaction survey. Weightbearing radiographs were compared with preoperative radiographs via an ankle arthritis classification system. Magnetic resonance imaging (MRI) was used to evaluate postoperative lesion characteristics per the MOCART scale (magnetic resonance observation of cartilage repair tissue). The size, location, lesion stability, traumatic etiology, skeletal maturity, and length of follow-up were recorded and analyzed through univariate logistic regression. RESULTS: The study group consisted of 22 patients (11 male, 11 female) with a mean age of 14.4 years (range, 8-18 years) and a mean follow-up of 8.3 years (range, 2-27 years). Of 22 patients, 20 were satisfied with the results from surgery and would recommend it to others. Mean follow-up visual analog scale for pain was reported as 2.2 on a 10-point scale, and mean American Orthopaedic Foot and Ankle Society score at follow-up was 86.6. Mean postoperative Foot Function Index scores for the study group were as follows: pain, 17.1; disability, 16.5; activity, 4.7; and overall, 38.7. Mean Short Form-36 physical component score was 50.7. Postoperative radiographs indicated a van Dijk osteoarthritis grade of 0 in 56%, I in 38%, II in 6%, and III in 0%. Postoperative MRI MOCART scores showed complete filling of the cartilage in 27% of cases, complete graft integration in 22%, and intact repair surface in 22%, with a mean MOCART score of 48.0. No correlation was found between radiographic and MRI findings and clinical outcomes. None of the prognostic factors were significantly associated with patient satisfaction, progression of arthritis, or MOCART scores. CONCLUSION: Arthroscopic treatment of symptomatic OLT in adolescent patients (≤18 years) demonstrated high functional outcomes, high clinical satisfaction rates, and minimal radiographic osteoarthritic progression despite low MOCART scores.

Mix-and-inject XFEL crystallography reveals gated conformational dynamics during enzyme catalysis.

How changes in enzyme structure and dynamics facilitate passage along the reaction coordinate is a fundamental unanswered question. Here, we use time-resolved mix-and-inject serial crystallography (MISC) at an X-ray free electron laser (XFEL), ambient-temperature X-ray crystallography, computer simulations, and enzyme kinetics to characterize how covalent catalysis modulates isocyanide hydratase (ICH) conformational dynamics throughout its catalytic cycle. We visualize this previously hypothetical reaction mechanism, directly observing formation of a thioimidate covalent intermediate in ICH microcrystals during catalysis. ICH exhibits a concerted helical displacement upon active-site cysteine modification that is gated by changes in hydrogen bond strength between the cysteine thiolate and the backbone amide of the highly strained Ile152 residue. These catalysis-activated motions permit water entry into the ICH active site for intermediate hydrolysis. Mutations at a Gly residue (Gly150) that modulate helical mobility reduce ICH catalytic turnover and alter its pre-steady-state kinetic behavior, establishing that helical mobility is important for ICH catalytic efficiency. These results demonstrate that MISC can capture otherwise elusive aspects of enzyme mechanism and dynamics in microcrystalline samples, resolving long-standing questions about the connection between nonequilibrium protein motions and enzyme catalysis.

The Effect of Option Homogeneity in Multiple-Choice Items.

Previous research has found that option homogeneity in multiple-choice items affects item difficulty when items with homogeneous options are compared to the same items with heterogeneous options. This study conducted an empirical test of the effect of option homogeneity in multiple-choice items on a professional licensure examination to determine the predictability and magnitude of the change. Similarity of options to the key was determined by using subject matter experts and a natural language processing algorithm. Contrary to current research, data analysis revealed no consistent effect on item difficulty, discrimination, fit to the measurement model, or response time associated with the absence or presence of option homogeneity. While the results are negative, they call into question established guidelines in item development. A hypothesis is proposed to explain why this effect is found in some studies but not others.

Reliability of the Tönnis Classification and Its Correlation With Magnetic Resonance Imaging and Intraoperative Chondral Damage.

PURPOSE: To evaluate the reliability of the Tönnis classification in the setting of femoroacetabular impingement (FAI) hips without dysplasia. METHODS: Forty-nine patients with FAI underwent preoperative radiography and magnetic resonance imaging (MRI). Radiographs were evaluated in 2 separate settings by 5 observers and graded according to the Tönnis classification. Interobserver and intraobserver reliability was calculated using the κ coefficient. Intraoperative chondral damage was assessed, and chondral damage to the acetabulum (acetabular labrum articular disruption [ALAD] classification) and to the femur (Outerbridge classification) was graded. The Spearman coefficient was computed to quantify the degree of correlation between the Tönnis grade and MRI-detected chondral damage, as well as intraoperative chondral damage. RESULTS: The average intraobserver reliability of the Tönnis classification was moderate (κ = 0.472), and the interobserver reliability was fair (κ = 0.287). Statistically significant positive correlations were found between the Tönnis classification and the ALAD classification (P = .0087) and between the Tönnis classification and femoral chondral damage detected by MRI (P = .0247). A statistically significant correlation was not found between the Tönnis grade and the intraoperative Outerbridge classification of the femur (P = .4969), between the Tönnis grade and acetabular chondral damage on MRI (P = .4969), or between the Tönnis grade and the ability to detect a chondral flap on MRI (P = .2160). No statistically significant correlation was found between the ALAD classification and the presence or absence of a chondral flap on MRI (P = .3538), between the ALAD classification and MRI-detected chondral damage to the acetabulum (P = .103), or between the Outerbridge classification and the degree of chondral damage observed on MRI of the femur (P = .1922). CONCLUSIONS: The Tönnis classification and MRI have substantial limitations when evaluating nondysplastic hips with FAI for the degree of chondral damage and arthritis. LEVEL OF EVIDENCE: Level III, retrospective comparative study of prospective data.

Arthroscopic Ankle Arthrodesis: A 2-15 Year Follow-up Study.

PURPOSE: The purpose of our study was to determine the results of arthroscopic ankle arthrodesis (AAA) and how the procedure affects adjoining joints and functional scores. METHODS: Between 1993 and 2013, 116 patients (120 ankles) underwent AAA. Nineteen ankles were lost to follow-up due to death, insufficient radiographic studies, or inability to contact, resulting in 97 patients (101 ankles). Mean age at surgery was 61.1 years (range, 35.8-79.6 years); mean follow-up was 86 months (range, 24-247 months). Patients were assessed according to the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle and Hindfoot scale, Ankle Osteoarthritis Scale (AOS), and Foot and Ankle Outcome Score (FAOS) and underwent comprehensive clinical and radiographic examinations. RESULTS: A total of 94.6% of patients achieved ankle fusion on radiographs. Mean AOFAS score was 83.3 (standard deviation [SD], 13.2). Mean modified FAOS score was 87.4 (SD, 10.4). The AOS scoring system showed 75% good/excellent results. According to the Kellgren-Lawrence score and van Dijk osteoarthritis grading scale, 85% and 69% of patients had no change in talonavicular or subtalar grade of osteoarthritis, respectively. There were no cases of deep infection or other serious adverse events. All but 4 patients were able to return to work following AAA. CONCLUSIONS: AAA is an effective operation for treating degenerative ankle disease, even in cases of moderate tibiotalar coronal deformity. At a mean of 86 months postop, nearly three quarters of our patients had good/excellent functional outcomes. Arthritis found in the adjacent hindfoot joints at the time of tibiotalar fusion appears to be a function of preexisting arthritic change and not directly caused by the tibiotalar fusion. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Correlation of MRI Appearance of Autologous Chondrocyte Implantation in the Ankle with Clinical Outcome.

The objective of this study was to characterize magnetic resonance imaging (MRI) findings and correlate with clinical results in patients who underwent autologous chondrocyte implantation (ACI) of osteochondral lesions of the talus (OLT). METHODS: Twenty-four grafts were evaluated at a mean 65.8 months after ACI for OLT. MRI was performed on a 1.5-T GE scanner using multiple sequences. Graft appearance was compared with preoperative MRI and evaluated for 6 criteria: defect fill, surface regularity, signal pattern, bone marrow edema, subchondral plate irregularity, and presence of cystic lesions. Clinical outcome was measured with the American Orthopaedic Foot and Ankle Society (AOFAS) clinical outcome score. RESULTS: Of 24 grafts, 22 (92%) demonstrated >75% defect fill. Eighteen (75%) had a mildly irregular and 6 (25%) had a moderately irregular articular surface. The signal pattern of the repair tissue was heterogenous in 23 (96%); 14 (58%) layered and 9 (38%) mottled. Fourteen grafts (58%) showed decreased amount of bone marrow edema while 4 (17%) had no change and 5 (21%) had an increase in the amount of bone marrow edema. The subchondral bone plate was abnormal in most grafts, with focal defects seen in 10, slight depression in 7, and both in 5. Seven had an increase in cystic lesions while the others had no change, decrease or no cysts seen. Mean postoperative AOFAS score was 87.5 with mean improvement of 39.4. CONCLUSIONS: At 66-month mean follow-up, MRI appearance of the ACI grafts show imaging abnormalities but demonstrate good clinical results. While MRI is an important tool in the postoperative assessment of ACI grafts, the various variations from a normal/nonoperative ankle must be interpreted with caution.

Exploiting Enzymatic Dynamic Reductive Kinetic Resolution (DYRKR) in Stereocontrolled Synthesis.

Over the past two decades, the domains of both frontline synthetic organic chemistry and process chemistry and have seen an increase in crosstalk between asymmetric organic/organometallic approaches and enzymatic approaches to stereocontrolled synthesis. This review highlights the particularly auspicious role for dehydrogenase enzymes in this endeavor, with a focus on dynamic reductive kinetic resolutions (DYRKR) to "deracemize" building blocks, often setting two stereocenters in so doing. The scope and limitations of such dehydrogenase-mediated processes are overviewed, as are future possibilities for the evolution of enzymatic DYRKR.

Combining a Clostridial enzyme exhibiting unusual active site plasticity with a remarkably facile sigmatropic rearrangement: rapid, stereocontrolled entry into densely functionalized fluorinated phosphonates for chemical biology.

Described is an efficient stereocontrolled route into valuable, densely functionalized fluorinated phosphonates that takes advantage of (i) a Clostridial enzyme to set the absolute stereochemistry and (ii) a new [3,3]-sigmatropic rearrangement of the thiono-Claisen variety that is among the fastest sigmatropic rearrangements yet reported. Here, a pronounced rate enhancement is achieved by distal fluorination. This rearrangement is completely stereoretentive, parlaying the enzymatically established ß-C-O stereochemistry in the substrate into the δ-C-S stereochemistry in the product. The final products are of interest to chemical biology, with a platform for Zn-aminopeptidase A inhibitors being constructed here. The enzyme, Clostridium acetobutylicum (CaADH), recently expressed by our group, reduces a spectrum of γ,δ-unsaturated ß-keto-α,α-difluorophosphonate esters (93-99% ee; 10 examples). The resultant ß-hydroxy-α,α-difluorophosphonates possess the "L"-stereochemistry, opposite to that previously observed for the CaADH-reduction of ω-keto carboxylate esters ("D"), indicating an unusual active site plasticity. For the thiono-Claisen rearrangement, a notable structure-reactivity relationship is observed. Measured rate constants vary by over 3 orders of magnitude, depending upon thiono-ester structure. Temperature-dependent kinetics reveal an unusually favorable entropy of activation (ΔS(‡) = 14.5 ± 0.6 e.u.). Most notably, a 400-fold rate enhancement is seen upon fluorination of the distal arene ring, arising from favorable enthalpic (ΔΔH(‡) = -2.3 kcal/mol) and entropic (ΔΔS(‡) = 4 e.u., i.e. 1.2 kcal/mol at rt) contributions. The unusual active site plasticity seen here is expected to drive structural biology studies on CaADH, while the exceptionally facile sigmatropic rearrangement is expected to drive computational studies to elucidate its underlying entropic and enthalpic basis.

Autologous chondrocyte implantation of the ankle: 2- to 10-year results.

BACKGROUND: The treatment of osteochondral lesions of the talus after failed surgery is challenging, with no clear solution. Short-term results using autologous chondrocyte implantation have been promising. PURPOSE: To report the long-term outcomes of patients who underwent autologous chondrocyte implantation (ACI) of the talus after failed marrow stimulation techniques for osteochondral lesions of the talus (OLTs). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty-two consecutive patients underwent ACI of the talus, and 29 patients (15 male, 14 female; mean age, 34 years [range, 16-54 years]) were available for follow-up. There were 23 medial and 6 lateral lesions, with a mean size of 18 × 11 mm (198 mm(2); range, 80-500 mm(2)). Twenty patients underwent ACI of the talus alone; 9 underwent ACI with bone grafting of underlying cysts. Follow-up was performed at a mean of 70 months (range, 24-129 months). Patient outcomes were evaluated using the simplified symptomatology score, Tegner activity score, Finsen score, and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. Twenty-five patients (86%) underwent second-look arthroscopic surgery at the time of hardware removal and were assessed with the International Cartilage Repair Society (ICRS) score. Postoperative magnetic resonance imaging (MRI) was performed on 24 patients (83%) and compared with preoperative MRI scans. RESULTS: Preoperatively, 26 patients rated their ankles as poor and 3 as fair using the simplified symptomatology score. At last follow-up, 9 were classified as excellent, 14 as good, 5 as fair, and 1 as poor using the same score. The mean AOFAS score improved from 50.1 to 85.9 (range, 65-100). The mean Tegner activity score improved from 1.6 to 4.3 (P < .0001). The mean Finsen score (modified Weber score) showed significant improvement from 13.7 to 5.1 (P < .0001). CONCLUSION: Autologous chondrocyte implantation of the talus yields improvement in all parameters tested with enduring long-term results in patients who have failed previous surgery for OLTs.

The "LIFT" lesion: lateral inverted osteochondral fracture of the talus.

PURPOSE: The purpose of this study was to assess a series of lateral inverted osteochondral fractures of the talus. METHODS: Over a 17-year period, 10 patients with an acute lateral inverted osteochondral fracture of the talus after an inversion injury to the ankle were identified. Diagnosis was made by physical examination, radiographs, magnetic resonance imaging, and/or computed tomography scan. Arthroscopy was initially performed on all patients. All patients had an inverted osteochondral fragment. In 8 of 10 patients the fragment was reattached in an open manner in conjunction with lateral ligament reefing. The fragment was excised in 2 patients. The mean age of the patients was 17.2 years. They were evaluated with the Single Assessment Numeric Evaluation, American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale, modified Weber score, Berndt and Harty score, and Short Form 36 version 2 score. Physical and radiographic examination was also performed. The mean time to follow-up was 112.3 months (9.3 years). RESULTS: The mean American Orthopaedic Foot and Ankle Society score improved from 18.9 preoperatively to 86.9 postoperatively (P ≤ .0001). The mean Single Assessment Numeric Evaluation and modified Weber scores were 81.6 and 81.5, respectively. On the Berndt and Harty scale, 6 patients had a good to excellent rating; 3, fair; and 1, poor. The mean Short Form 36 version 2 scores corresponded to national averages for healthy populations. Mean loss of motion for dorsiflexion and plantarflexion was 6.8° and 3.0°, respectively, when compared with the contralateral side. All patients showed some osteophyte formation on follow-up radiographs. CONCLUSIONS: An inverted osteochondral fracture of the lateral talus (lateral, inverted, fracture, talus [LIFT lesion]) can occur after a twisting injury to the ankle. Clinical suspicion should be high, especially in the younger athlete. This injury can be successfully managed with a combined arthroscopic and open approach. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

A new dehydrogenase from Clostridium acetobutylicum for asymmetric synthesis: dynamic reductive kinetic resolution entry into the Taxotère side chain.

An NADP-dependent alcohol dehydrogenase from Clostridium acetobutylicum (CaADH) has been expressed and characterized. CaADH enantioselectively reduces aromatic α-, ß- and γ-keto esters to the corresponding D-hydroxy esters and provides a building block for the Taxotère side chain (95% yield, 95% de, 99% ee) by dynamic reductive kinetic resolution (DYRKR).

Continuous transversus abdominis plane (TAP) block catheters in a combat surgical environment.

OBJECTIVES: The ongoing conflict in Afghanistan continues to generate a large number of complex trauma injuries and provides unique challenges to military anesthetists working in forward field hospitals. We report successful use of ultrasound-guided continuous transversus abdominis plane (TAP) block in two Afghan war casualties who sustained major trauma with coagulopathy. The use of bilateral continuous TAP blocks following major thoracoabdominal trauma in a combat environment is unique in the literature. DESIGN: Case report. RESULTS: The acute perioperative outcomes of two Afghan civilian patients were improved with bilateral continuous TAP blocks. Multiple benefits shared by both patients included early extubation, excellent analgesia, and minimal post-operative morphine requirements despite the setting of a massive blood transfusion and coagulopathy. CONCLUSIONS: A continuous TAP block technique can be utilized to provide excellent analgesia following major abdominal surgery when neuraxial anesthesia is contraindicated. The TAP block's ease of placement under ultrasound guidance makes this technique particularly useful in the austere battlefield hospital environment.

MRI evaluation of anterolateral soft tissue impingement of the ankle.

BACKGROUND: The usefulness of magnetic resonance imaging (MRI) has been questioned in evaluating patients with chronic ankle sprain pain. The purpose of this study was to determine the effectiveness and reliability of routine MR imaging in the diagnosis of anterolateral soft tissue impingement. MATERIALS AND METHODS: Inclusion criteria required that the MR examinations be performed by the same musculoskeletal radiologist after the most recent scanner upgrade and using a dedicated ankle/hindfoot coil. The surgical and MRI reports of 24 patients who had an arthroscopic diagnosis of anterolateral soft tissue impingement of the ankle were tabulated and categorized. Unlike previous studies, sagittal T1 and Short Tau Inversion Recovery (STIR) images were used primarily in the diagnosis of these lesions. RESULTS: Using this technique, we report a 78.9% accuracy in diagnosis, a sensitivity of 83.3% and a specificity of 78.6%. Fifty-eight percent of patients had an associated diagnosis, which in 33% of patients altered our surgical plan. CONCLUSION: Although not indicated in all cases of anterolateral ankle impingement, we advocate the use of MR imaging in complicated clinical presentations where the exclusion of additional pathology in the ankle or subtalar joint, and the confirmation of anterolateral soft tissue impingement would be beneficial.

Evaluation of sequential extraction procedures for soluble and insoluble hexavalent chromium compounds in workplace air samples.

Because toxicities may differ for Cr(VI) compounds of varying solubility, some countries and organizations have promulgated different occupational exposure limits (OELs) for soluble and insoluble hexavalent chromium (Cr(VI)) compounds, and analytical methods are needed to determine these species in workplace air samples. To address this need, international standard methods ASTM D6832 and ISO 16740 have been published that describe sequential extraction techniques for soluble and insoluble Cr(VI) in samples collected from occupational settings. However, no published performance data were previously available for these Cr(VI) sequential extraction procedures. In this work, the sequential extraction methods outlined in the relevant international standards were investigated. The procedures tested involved the use of either deionized water or an ammonium sulfate/ammonium hydroxide buffer solution to target soluble Cr(VI) species. This was followed by extraction in a sodium carbonate/sodium hydroxide buffer solution to dissolve insoluble Cr(VI) compounds. Three-step sequential extraction with (1) water, (2) sulfate buffer and (3) carbonate buffer was also investigated. Sequential extractions were carried out on spiked samples of soluble, sparingly soluble and insoluble Cr(VI) compounds, and analyses were then generally carried out by using the diphenylcarbazide method. Similar experiments were performed on paint pigment samples and on airborne particulate filter samples collected from stainless steel welding. Potential interferences from soluble and insoluble Cr(III) compounds, as well as from Fe(II), were investigated. Interferences from Cr(III) species were generally absent, while the presence of Fe(II) resulted in low Cr(VI) recoveries. Two-step sequential extraction of spiked samples with (first) either water or sulfate buffer, and then carbonate buffer, yielded quantitative recoveries of soluble Cr(VI) and insoluble Cr(VI), respectively. Three-step sequential extraction gave excessively high recoveries of soluble Cr(VI), low recoveries of sparingly soluble Cr(VI), and quantitative recoveries of insoluble Cr(VI). Experiments on paint pigment samples using two-step extraction with water and carbonate buffer yielded varying percentages of relative fractions of soluble and insoluble Cr(VI). Sequential extractions of stainless steel welding fume air filter samples demonstrated the predominance of soluble Cr(VI) compounds in such samples. The performance data obtained in this work support the Cr(VI) sequential extraction procedures described in the international standards.

Autologous chondrocyte implantation of the ankle: a 2- to 5-year follow-up.

BACKGROUND: Treatment of full-thickness talar cartilage defects that have failed previous surgery is problematic without a definitive solution. PURPOSE: To report the first US prospective study of autologous chondrocyte implantation of the talus. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Eleven patients (6 women and 5 men; mean age, 33 years) underwent autologous chondrocyte implantation of the talus after previous failed surgical management. There were 9 medial and 2 lateral lesions, with a mean size of 21 x 13 mm (273 mm2). Five patients underwent autologous chondrocyte implantation of the talus alone; 6 had it with a "sandwich procedure." Ten patients underwent a second-look arthroscopy with screw removal. RESULTS: Mean follow-up was 38 months. Preoperatively, 10 patients rated their ankles as poor and 1 as fair, using the simplified symptomatology evaluation. At latest follow-up, 3 patients were classified as excellent, 6 as good, and 2 as fair. Tegner activity level improved from 1.3 +/- 1.0 (mean +/- SE) preoperatively to 4.0 +/- 1.6 (P < .002) postoperatively. The Finsen score (modified Weber score) showed significant improvement in the total score (P < .001). There was also overall agreement between the Finsen score and the American Orthopaedic Foot and Ankle Society ankle hindfoot score, with significant improvement from 47.4 +/- 17.4 preoperatively to 84.3 +/- 8.1 postoperatively (P < .001). At repeat arthroscopy, complete coverage of the defect was seen in all patients. CONCLUSION: Autologous chondrocyte implantation of the talus yields significant functional improvement; however, further investigation is necessary to determine the long-term structural and biomechanical properties of the repair tissue.

Arthroscopic treatment of chronic osteochondral lesions of the talus: long-term results.

BACKGROUND: Osteochondral lesions of the talus are relatively uncommon but may be a cause of significant pain and disability in symptomatic patients. HYPOTHESIS: Arthroscopic treatment of osteochondral lesions of the talus will result in good long-term clinical outcomes in the majority of patients. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Fifty patients with chronic osteochondral lesions of the talus underwent arthroscopic treatment. Average age was 32 years (range, 12-72 years). Average follow-up was 71 months (range, 24-152 months). Treatment consisted of either drilling of the osteochondral lesions of the talus in situ (n = 4), excision of the osteochondral lesions of the talus and abrasion arthroplasty (n = 6), or excision of the osteochondral lesions of the talus and drilling (n = 40). Preoperative and intraoperative staging of the osteochondral lesions of the talus was performed. Follow-up evaluation included 3 clinical rating systems: Alexander, modified Weber, and American Orthopaedic Foot and Ankle Society Ankle/Hindfoot scores. RESULTS: There were 72% excellent/good, 20% fair, and 8% poor results on the Alexander scale. According to the modified Weber scale, there were 64% excellent/good, 30% fair, and 6% poor results. The average American Orthopaedic Foot and Ankle Society Ankle/Hindfoot score was 84 (range, 34-100). We found no correlation between plain radiographs, computed tomography, or magnetic resonance imaging staging and clinical results. However, there was significant correlation between arthroscopic stage and clinical outcome. Seventeen patients had been seen 5 years previously and evaluated using the same criteria; 35% demonstrated a deterioration in their result over time. CONCLUSION: Arthroscopic treatment of chronic symptomatic osteochondral lesions of the talus results in good clinical outcomes in the majority of patients. However, pain and functional limitation may persist in some patients, especially those noted to have unstable osteochondral defects at the time of arthroscopy.

Meniscus allograft transplantation: ten-year results of cryopreserved allografts.

PURPOSE: We report the results of cryopreserved meniscus allograft transplantations with 10 or more years of follow-up. METHODS: Fourteen medial and 8 lateral meniscus allografts were evaluated with a mean follow-up of 141 months (range, 115 to 167 months). The clinical outcome and failure rate was evaluated by use of a Lysholm score and modified pain score in 22 patients. The results of radiographic and magnetic resonance imaging (MRI) analysis were reported in 15 and 7 patients, respectively. RESULTS: Overall, 25% of medial allografts and 50% of lateral allografts failed. The combined failure rate was 35%. There was a 90% improvement in Lysholm scores, as well as pain scores. There were no discernible Lysholm or pain score differences for both lateral and medial allografts. Furthermore, there was no discernible difference in both Lysholm and pain scores between bone plug and soft-tissue methods of graft fixation. Ten of fifteen allografts showed radiographic joint space narrowing, and twelve had progression of degenerative joint disease. On MRI, all grafts had moderate meniscus shrinkage and five had grade III signal intensities. Eighty-five percent of patients underwent subsequent procedures, 5 of whom required total allograft resection and 2 of whom required partial allograft resection. One allograft required repair. CONCLUSIONS: Although transplantation of cryopreserved allografts improved knee pain and function, the average knee function was fair at long-term follow-up. Fifty-five percent of allografts failed when failure criteria for second-look surgery, knee improvement surveys, and MRI were added to Lysholm and pain score failures. The protective benefits of meniscus allografts remain debatable, and inferences cannot be made from this study. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Evaluation of a standardized micro-vacuum sampling method for collection of surface dust.

A standardized procedure for collecting dust samples from surfaces using a micro-vacuum sampling technique was evaluated. Experiments were carried out to investigate the collection efficiency of the vacuum sampling method described in ASTM Standard D7144, "Standard Practice for Collection of Surface Dust by Micro-Vacuum Sampling for Subsequent Metals Determination." Weighed masses ( approximately 5, approximately 10 and approximately 25 mg) of three NIST Standard Reference Materials (SRMs) were spiked onto surfaces of various substrates. The SRMs used were: (1) Powdered Lead-Based Paint; (2) Urban Particulate Matter; and (3) Trace Elements in Indoor Dust. Twelve different substrate materials were chosen to be representative of surfaces commonly encountered in occupational and/or indoor settings: (1) wood, (2) tile, (3) linoleum, (4) vinyl, (5) industrial carpet, (6) plush carpet, (7,8) concrete block (painted and unpainted), (9) car seat material, (10) denim, (11) steel, and (12) glass. Samples of SRMs originally spiked onto these surfaces were collected using the standardized micro-vacuum sampling procedure. Gravimetric analysis of material collected within preweighed Accucapinserts (housed within the samplers) was used to measure SRM recoveries. Recoveries ranged from 21.6% (+/- 10.4%, 95% confidence limit [CL]) for SRM 1579 from industrial carpet to 59.2% (+/- 11.0%, 95% CL) for SRM 1579 from glass. For most SRM/substrate combinations, recoveries ranged from approximately 25% to approximately 50%; variabilities differed appreciably. In general, SRM recoveries were higher from smooth and hard surfaces and lower from rough and porous surfaces. Material captured within collection nozzles attached to the sampler inlets was also weighed. A significant fraction of SRM originally spiked onto substrate surfaces was captured within collection nozzles. Percentages of SRMs captured within collection nozzles ranged from approximately 13% (+/- 4 - +/- 5%, 95% CLs) for SRMs 1579 and 2583 from industrial carpet to approximately 45% (+/- 7 - +/- 26%, 95% CLs) for SRM 1648 from glass, tile and steel. For some substrates, loose material from the substrate itself (i.e., substrate particles and fibers) was sometimes collected along with the SRM, both within Accucaps as well as collection nozzles. Co-collection of substrate material can bias results and contribute to sampling variability. The results of this work have provided performance data on the standardized micro-vacuum sampling procedure.

Chronic labral tears: value of magnetic resonance arthrography in evaluating the glenoid labrum and labral-bicipital complex.

PURPOSE: In the magnetic resonance (MR) evaluation of the glenoid labrum, all studies to our knowledge have included mixed populations of patients, those with acute shoulder injuries as well as patients with chronic shoulder disorders. The focus of this investigation was to assess the effectiveness of MR arthrography in patients with chronic labral tears, excluding those with acute injuries. TYPE OF STUDY: Prospective case series. METHODS: Conventional MR images and MR arthrograms were obtained in 36 patients from April 1994 to April 1997. A single experienced musculoskeletal radiologist read all MR images. Each patient subsequently underwent shoulder arthroscopy performed by a single highly experienced shoulder arthroscopist. Detailed arthroscopic reports were then reviewed and compared with the MR findings documented before surgery, with arthroscopic findings being the standard of reference for comparison. Inclusion criteria required greater than 6 months of shoulder symptoms before imaging, thus eliminating acute injuries. RESULTS: SLAP lesions were diagnosed at the time of surgery in 11 of 36 patients (31%). The sensitivity was 100% (11 of 11 patients) and the specificity was 88% (22 of 25 patients). Accuracy for SLAP lesions was 92% (33 of 36 patients). Anterior labral tears were diagnosed surgically in 12 of 36 patients (33%). The sensitivity was 86% (12 of 14 patients) and specificity was 86% (19 of 22 patients). Accuracy for labral tears was 86% (31 of 36 patients). CONCLUSIONS: MR arthrography is an accurate technique for assessing the glenoid labrum in patients with chronic labral tears. LEVEL OF EVIDENCE: Level I.