Biomedical subjects

Kevin P Murphy

Publications and source records attributed to Kevin P Murphy.

17 recordsLinked to original sources

PubMed2006

Diagnosis of superior labral lesions: comparison of noncontrast MRI with indirect MR arthrography in unexercised shoulders.

OBJECTIVE: To prospectively compare the accuracy of noncontrast magnetic resonance imaging (MRI) with indirect MR arthrography (I-MRa) of unexercised shoulders for diagnosis of superior glenoid labral lesions. MATERIALS AND METHODS: Institutional Review Board approval and patient informed consent were obtained for this prospective study. Superior labral findings on shoulder MRI and unexercised I-MRa studies of 104 patients were correlated with findings at arthroscopic shoulder surgery. Two musculoskeletal radiologists independently reviewed the two sets of MR images while blinded to arthroscopic results. For each radiologist, the McNemar test was used to detect statistically significant differences between techniques. RESULTS: The superior labrum was intact in 24 and abnormal in 80 subjects. For detection of superior labral lesions by each radiologist, I-MRa was more sensitive (84-91%) than MRI (66-85%), with statistically significant improvement in sensitivity for one reader (p = 0.003). However, I-MRa was less specific (58-71%) than MRI (75-83%). Overall, accuracy was slightly improved on I-MRa (78-86%) compared with MRI (70-83%), but this difference was not statistically significant for either reader. CONCLUSION: Compared with noncontrast MRI, I-MRa was more sensitive for diagnosis of superior glenoid labral lesions. However, the diagnostic value of I-MRa in shoulders remaining at rest is potentially limited by decreased specificity of the technique.

Adolescent↗

PubMed2006

Integrating copy number polymorphisms into array CGH analysis using a robust HMM.

MOTIVATION: Array comparative genomic hybridization (aCGH) is a pervasive technique used to identify chromosomal aberrations in human diseases, including cancer. Aberrations are defined as regions of increased or decreased DNA copy number, relative to a normal sample. Accurately identifying the locations of these aberrations has many important medical applications. Unfortunately, the observed copy number changes are often corrupted by various sources of noise, making the boundaries hard to detect. One popular current technique uses hidden Markov models (HMMs) to divide the signal into regions of constant copy number called segments; a subsequent classification phase labels each segment as a gain, a loss or neutral. Unfortunately, standard HMMs are sensitive to outliers, causing over-segmentation, where segments erroneously span very short regions. RESULTS: We propose a simple modification that makes the HMM robust to such outliers. More importantly, this modification allows us to exploit prior knowledge about the likely location of "outliers", which are often due to copy number polymorphisms (CNPs). By "explaining away" these outliers with prior knowledge about the locations of CNPs, we can focus attention on the more clinically relevant aberrated regions. We show significant improvements over the current state of the art technique (DNAcopy with MergeLevels) on previously published data from mantle cell lymphoma cell lines, and on published benchmark synthetic data augmented with outliers. AVAILABILITY: Source code written in Matlab is available from http://www.cs.ubc.ca/~sshah/acgh.

Artificial Intelligence↗

PubMed2006

Repair of the adult acetabular labrum.

Although hip arthroscopy is a new technique, indications for its use are rapidly expanding. With better utilization and understanding of both radiologic assessment of hip pathology and clinical examination, specific intra-articular derangement is being identified. Longitudinal, peripheral, and intrasubstance anterior hip labral tears can be repaired using anterior paratrochanteric and anterior portals with standard hip arthroscopy equipment. Repair of the torn labrum may help re-establish the anatomic function of the labrum, thereby preventing biomechanical compromise through surgical debridement, which may lead to degenerative changes associated with osteoarthritis. Although long-term results are still unknown, results of short-term follow-up are positive.

Acetabulum↗

PubMed2006

Prognostic value of magnetic resonance arthrography for Czerny stage II and III acetabular labral tears.

PURPOSE: To assess the intraobserver reliability and prognostic value of magnetic resonance arthrography (MRA) on the basis of postoperative outcome measures following arthroscopic acetabular labral debridement (partial limbectomy). METHODS: Between January 1999 and November 2000, 24 patients (13 females, 11 males) with an average age of 37.1 years (range, 21 to 56 years) underwent hip arthroscopy for the treatment of presumed acetabular labral tears. All patients underwent preoperative MRA and/or magnetic resonance imaging (MRI); images were evaluated by a single musculoskeletal radiologist on 2 independent occasions. Hip arthroscopy was performed on all patients. Outcomes were assessed by means of the Modified Harris Hip Score (MHHS) and the Short Form-36 (SF-36) questionnaires, which were completed by patients an average of 24.1 months (range, 12 to 55 months) postoperatively. The accuracy of the initial read, as well as the prognostic value of the Czerny MRA classification system for stage II (intrasubstance tears) and stage III (complete avulsions) acetabular labral tears, was assessed. RESULTS: Twenty-two of 23 tears (96%) were detected on the initial read. On the basis of intraoperative findings, 1 false-positive MRA, 1 false-negative MRA, and 1 incident of MRA overstaging were reported. On repeat interpretation, 23 of 23 (100%) tears were identified, and intraobserver reliability for recording the presence of a tear was excellent (kappa coefficient = 0.96). No difference was noted in outcomes between patients with or without arthroscopic evidence of chondromalacia (all P > .29), or between patients older or younger than 30 years (all P > .34). Likewise, no difference in outcome was seen between 15 patients with Czerny stage II tears revealed on MRA versus 9 patients with Czerny stage III tears (all P > .79). CONCLUSIONS: MRA is sensitive and accurate for the detection of acetabular labral tears, with excellent intraobserver reliability. Arthroscopic partial limbectomy is successful in two thirds of patients. Patients with Czerny stage II and III tears do not appear to have significantly different outcomes following arthroscopic labral debridement. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Acetabulum↗

PubMed2006

Surgical treatment of acute lateral collateral ligament and posterolateral corner injuries.

Early surgical treatment of injuries to the posterolateral corner of the knee is recommended to promote rehabilitation for normal function of the knee. To optimize the chance at primary repair, surgery should be performed within 2 weeks; otherwise, reconstruction is the most viable option. During operative treatment, each component of the posterolateral corner is assessed individually, with primary repair performed if amenable to repair. Additional techniques, such as augmentation, advancement, or reconstruction may be needed if the primary repair is tenuous or the tissues damaged.

Collateral Ligaments↗

PubMed2006

Autologous hamstring anterior cruciate ligament reconstruction in patients older than 40.

The primary objective in this retrospective review was to assess the patient-specific outcomes and clinical utility of anterior cruciate ligament (ACL) reconstruction using the autologous quadruple-band hamstring technique in patients older than 40. Study results agree with the recent literature and demonstrate the effectiveness of an alternative to the bone-patellar tendon-bone (BPB) technique-an alternative with potentially decreased postoperative morbidity. Results also support the recent conclusion that age alone should not be a limiting factor in whether ACL reconstruction should be performed. We found that appropriately selected patients may experience significant improvements in stability, function, and pain after ACL reconstruction with the quadruple-band hamstring autograft technique. For outcomes after ACL reconstruction, there seems to be no significant difference between the sexes or between patients with and without associated injuries in this population. This study also supports use of the autologous hamstring technique as a viable option for older patients-with results similar to those of the BPB technique. The autologous hamstring technique was associated with excellent patient satisfaction and excellent functional outcome with limited postoperative morbidity. This technique may become the preferred approach for the older athlete, given its limited morbidity and equivalent clinical stability.

Adult↗

PubMed2005

Correlation of Short Form-36 and disability status with outcomes of arthroscopic acetabular labral debridement.

BACKGROUND: Arthroscopic debridement is the standard of care for the treatment of acetabular labral tears. The Short Form-36 has not been used to measure hip arthroscopy outcomes, and the impact of disability status on hip arthroscopy outcomes has not been reported. HYPOTHESIS: Short Form-36 subscale scores will demonstrate good correlation with the modified Harris hip score, but patients undergoing disability evaluation will have significantly worse outcome scores. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The records of active-duty soldiers who underwent hip arthroscopy at the authors' institution were retrospectively reviewed. Forty consecutive patients who underwent hip arthroscopy for the primary indication of labral tear formed the basis of the study group. Patients completed the modified Harris hip score, the Short Form-36 general health survey, and a subjective overall satisfaction questionnaire. RESULTS: Thirty-three patients, with a mean age of 34.6 years, were available for follow-up at a mean of 25.7 months postoperatively. Fourteen (43%) patients were undergoing medical evaluation boards (military equivalent of workers' compensation or disability claim). Pearson correlation coefficients for comparing the Short Form-36 Bodily Pain, Physical Function, and Physical Component subscale scores to the modified Harris hip score were 0.73, 0.71, and 0.85, respectively (P < .001). The mean modified Harris hip score was significantly lower in patients on disability status than in those who were not (92.4 vs 61.1; P < .0001). The Short Form-36 subscale scores were significantly lower in disability patients (P < .02). Patient-reported satisfaction rates (70% overall) were 50% for those undergoing disability evaluations and 84% for those who were not (P < .04). There was no significant difference in outcomes based on patient age, surgically proven chondromalacia, or gender for military evaluation board status. CONCLUSION: The Short Form-36 demonstrated good correlation with the modified Harris hip score for measuring outcomes after arthroscopic partial limbectomy. Arthroscopic debridement yielded a high percentage of good results when patients undergoing disability evaluations were excluded. Disability status may be a negative predictor of success after hip arthroscopy.

Acetabulum↗

PubMed2005

Initial evaluation of the acute and chronic multiple ligament injured knee.

Despite the recent focus on the limited use of urgent arteriograms in the evaluation of acute knee dislocations, physical examination remains the cornerstone of assessment. Several clinical scenarios dictate an orthopedic emergency: vascular disruption, open wound, compartment syndrome, or an irreducible joint/dimple sign. In the acute setting, every attempt should be made to rule out associated injuries and the need for intervention. The multiple ligament knee injury or knee dislocation is a complex dilemma that requires close attention. Concomitant injuries about the knee often arise and must be addressed prior to ligamentous repair, and therefore the orthopedic surgeon must maintain a high index of suspicion for associated injuries in the evaluation of a multiple ligament knee injury.

Diagnosis, Differential↗

PubMed2004

Purification and characterization of a recombinant version of human alpha-fetoprotein expressed in the milk of transgenic goats.

Alpha-Fetoprotein (AFP) is a 68 kDa glycoprotein expressed at high levels by the fetal liver and yolk with transcription repressed to very low levels after birth. Transfer of fetal AFP through the placenta into the circulation of the mother is correlated with remission of rheumatoid arthritis, multiple sclerosis, and other autoimmune disorders. AFP is therefore under development as a biopharmaceutical for the treatment of autoimmune diseases. The clinical evaluation of AFP requires the production of hundreds of grams of highly purified and biologically active protein. We have produced goats that express a form of the human AFP transgene under the control of the beta-casein promoter. In this form of rhAFP, the single N-linked glycosylation site was removed by mutagenesis (N233Q). Here, we describe a purification protocol for this recombinant human (rh)AFP from the milk of these transgenic goats. A three-column procedure was developed to produce gram quantities of highly purified rhAFP. Near- and far-UV circular dichroism spectra of human umbilical cord blood AFP and rhAFP were essentially identical, suggesting that the structure is not affected by removal of the glycosylation site. Furthermore, the cell binding and pharmacokinetics of purified rhAFP were similar to human AFP isolated from cord blood. Our results demonstrate that an active form of rhAFP can be produced on industrial scale by expression in transgenic goat milk.

Animals↗

PubMed2004

Evaluation of orthopaedic injuries in Operation Enduring Freedom.

Orthopaedic injuries constitute a majority of the combat casualties in recent U.S. military conflicts. Orthopaedic injuries sustained in Operation Enduring Freedom from December 2001 to January 2003 that were treated in forward-deployed military medial facilities and evacuated to a U.S. army medical center were reviewed. The spectrum of injuries included open fractures, amputations, neurovascular, and soft-tissue injuries. Forty-four patients (85%) received treatment beyond local wound care prior to arrival at a military medical center. Debridement and irrigation was the most commonly performed procedure due to the contaminated nature of these combat injuries. There were no infections among patients with open fractures, and no patients with external fixators had pin tract infections. None of the open fracture patients underwent primary internal fixation or primary wound closure. The average time from injury to wound coverage of the open fracture wounds was 12 days. Two amputations were infected and were treated with revision and delayed wound closure. There were no primary amputations done at our institution due to infection or ischemia. All arterial injuries underwent urgent revascularization in a field hospital. None of the arterial repairs required revision after evacuation to a medical center. Operation Enduring Freedom has been an excellent example of how early and aggressive intervention in a forward-deployed area has a significant effect on rehabilitative and reconstructive efforts at a rear echelon tertiary care center.

Adult↗

PubMed2004

Sublabral sulcus at the posteroinferior acetabulum: a potential pitfall in MR arthrography diagnosis of acetabular labral tears.

OBJECTIVE: Our study correlated findings on hip MRI and MR arthrography with hip arthroscopy to assess the location, prevalence, and potential pitfall of a normal acetabular sublabral sulcus. MATERIALS AND METHODS: We retrospectively collected 58 hip MRI studies along with surgical reports in 58 patients who underwent hip arthroscopy over a 5-year period. Intraoperative photography (n = 23), radiography (n = 56), unenhanced MRI (n = 13), and MR arthrography (n = 54) studies were available for review. Two radiologists described hip anatomy on radiology studies with agreement by consensus. RESULTS: A normal posteroinferior sublabral groove was confirmed on available arthroscopy photographs in four (17.4%) of 23 hips. In each of these four patients, the anatomic sublabral groove correlated with apparent partial labral detachment on MR arthrography. On review of all studies, 13 hips (22.4%) without a posterior labral tear at surgery had imaging findings of a sublabral sulcus. The sulcus was not associated with acetabular dysplasia, which was radiographically noted in 12 cases (21.4%). Preoperatively, the sulcus was misdiagnosed as a tear in two cases. Labral tears were anterior or anterosuperior in 51 patients. CONCLUSION: A posteroinferior sublabral groove is a relatively common normal anatomic hip variation. If not recognized as normal, the sulcus may serve as a diagnostic pitfall on MR arthrography. Its location is distinct from most labral tears. We did not discover a sublabral sulcus at the anterior or anterosuperior acetabulum, the most common sites of labral injury.

Acetabulum↗

PubMed2004

Orthopedic injuries during Operation Enduring Freedom.

Orthopedic injuries comprise a majority of combat injuries seen in recent U.S. military conflicts. Interventions in the forward deployed area have played an important role in improving mortality rates of soldiers as well as outcome at a medical center level. A retrospective review was conducted on orthopedic injuries from Operation Enduring Freedom evaluated at Walter Reed Army Medical Center (WRAMC). Patients were grouped into one of five injury categories (open fracture, amputation, arterial injuries, neurological injuries, and soft tissue injury) with evacuation time (days from time of injury to arrival at WRAMC) and procedures performed before arrival at WRAMC evaluated. The average evacuation time for all orthopedic casualties was 7.9 days. There was an average of 2.6 procedures performed per patient before arrival at WRAMC. There was no difference in evacuation time among the injury groups. Those with only soft tissue injuries underwent fewer procedures than the other injury groups; however, there was no difference among the injury groups in terms of procedures performed. The number of procedures performed did not affect the evacuation time. Fifty-six percent of casualties required operative intervention after arrival at WRAMC. With the unavoidable evacuation time that all casualties must endure regardless of severity of the injury, early operative intervention in forward deployed medical assets, such as the forward surgical team and combat support hospital, remains a necessity for rehabilitative and reconstructive efforts of the soldiers at the medical center level.

Adult↗

PubMed2003

Hip arthroscopy for osteochondral loose body removal after a posterior hip dislocation.

We report on the application of hip arthroscopy to remove an osteochondral fragment created by a posterior hip dislocation. Preoperative and postoperative radiographs and computed tomography scans correlate with intraoperative arthroscopic photographs and are presented with this report. Arthroscopy allowed excellent visualization of the joint and facilitated straightforward removal of the fragment. We were able to avoid the larger incision required by an arthrotomy and decreased the patient's overall morbidity from this condition.

Accidents, Aviation↗

PubMed2003

Modified arthroscopic suture fixation of a displaced tibial eminence fracture.

This study describes a new arthroscopic method using a whip-stitch technique for treating a displaced type III tibial eminence fracture. A 12-year-old girl who sustained a displaced type III tibial eminence fracture was treated with arthroscopic fixation using the Arthrosew disposable suture device (Surgical Dynamics, Norwalk, CT) to place a whip stitch into the anterior cruciate ligament (ACL). The Arthrex ACL guide (Arthrex, Naples, FL) was used to reduce the avulsed tibial spine fragment. Sutures were then passed through the tibial tunnel and secured over a bony bridge with the knee in 20 degrees of flexion. At 9 months, the patient has a full range of motion with normal Lachman and anterior drawer testing, and she has returned to competitive basketball. Radiographs show complete fracture healing. KT-1000 and isokinetic testing at 9-month follow-up show only minimal side-to-side differences. The Arthrosew device provides a significant advantage in the treatment of type III and IV fractures of the tibial eminence by obtaining arthroscopic fixation within the substance of the ACL, thus obviating arthrotomy and hardware placement. This technique also restores the proper length and tension to the ACL, and provides a simplified, reproducible method of treatment for this injury.

Anterior Cruciate Ligament↗

PubMed2002

Accelerated stability model for predicting shelf-life.

Second- and higher-order degradation reactions sometimes cannot be approximated with linear or exponential relationships and need to be appropriately modeled. Events above the COULTER HmX Analyzer white blood cell (WBC) counting threshold were recorded for the HmX PAK reagent system stored at five elevated temperatures. An accelerated stability model for a second-degree polynomial degradation pattern was used. The shelf-life of the reagent, along with 95% lower bound confidence intervals, is predicted using the same pattern of degradation as well as the Arrhenius approximation. Experiments indicated that the degradation of the HmX PAK reagent occurred in two phases, the lag phase and the degradation phase, in all tested temperatures. The phase durations are temperature-dependent, and the Arrhenius approximation is appropriate (P=0.639). The degradation of the reagent during the lag phase was experimentally undetectable. Changes of the reagent were nonsignificant for a predicted period of 164 days at 25 degrees C. The rate of degradation increased significantly later on during the degradation phase. The lower bound of the 95% confidence interval of this prediction indicated that it would take at least 326 days before the HmX PAK reagent would have any performance issue related to aging at storage temperature.

Autoanalysis↗

PubMedDate not supplied

Evaluation of orthopaedic injuries in Operation Enduring Freedom.

Orthopaedic injuries constitute a majority of the combat casualties in recent U.S. military conflicts. Orthopaedic injuries sustained in Operation Enduring Freedom from December 2001 to January 2003 that were treated in forward-deployed military medical facilities and evacuated to a U.S. army medical center were reviewed. The spectrum of injuries included open fractures, amputations, neurovascular, and soft-tissue injuries. Forty-four patients (85%) received treatment beyond local wound care prior to arrival at a military medical center. Debridement and irrigation was the most commonly performed procedure due to the contaminated nature of these combat injuries. There were no infections among patients with open fractures, and no patients with external fixators had pin tract infections. None of the open fracture patients underwent primary internal fixation or primary wound closure. The average time from injury to wound coverage of the open fracture wounds was 12 days. Two amputations were infected and were treated with revision and delayed wound closure. There were no primary amputations done at our institution due to infection or ischemia. All arterial injuries underwent urgent revascularization in a field hospital. None of the arterial repairs required revision after evacuation to a medical center. Operation Enduring Freedom has been an excellent example of how early and aggressive intervention in a forward-deployed area has a significant effect on rehabilitative and reconstructive efforts at a rear echelon tertiary care center.

Adult↗

PubMedDate not supplied

Braided hamstring tendons for reconstruction of the anterior cruciate ligament. A biomechanical analysis.

BACKGROUND: In an effort to improve the strength and stiffness of anterior cruciate ligament grafts, several authors have advocated alterations of graft structure and orientation, including braiding the tendons in hamstring tendon grafts. HYPOTHESIS: Braiding hamstring tendons does not increase graft strength and stiffness. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen hamstring tendon and 21 bone-patellar tendon-bone grafts were harvested from 12 cadavers and divided into three groups: 1) braided four-strand hamstring tendon, 2) unbraided four-strand hamstring tendon, and 3) bone-patellar tendon-bone. All grafts were placed under a 50-N preload on a servohydraulic testing device and were tensioned to failure. RESULTS: The strength and stiffness of the tested specimens averaged 427 +/- 36 N and 76 +/- 10 N/mm, respectively, for braided specimens, 532 +/- 44 N and 139 +/- 18 N/mm for unbraided specimens, and 574 +/- 46 N and 158 +/- 15 N/mm for patellar tendon specimens. There was a 20% decrement in hamstring tendon graft tensile strength and a 45% decrease in stiffness after braiding because of the suboptimal multidirectional orientation of individual tendons within the braided grafts. CONCLUSIONS: In vitro braided hamstring tendon grafts demonstrated mechanically inferior strength and stiffness characteristics compared with unbraided hamstring tendon grafts and patellar tendon grafts. CLINICAL RELEVANCE: Braiding of hamstring tendon grafts provides no mechanical advantage in anterior cruciate ligament reconstruction.

Aged↗