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Biomedical subjects

Daniel P O'Connor

Publications and source records attributed to Daniel P O'Connor.

At least 19 recordsLinked to original sources
PubMed2007

Exchange nailing of ununited fractures.

Exchange nailing is most appropriate for a nonunion without substantial bone loss. There is no clear consensus regarding the use of exchange nailing in the presence of active, purulent infection. The exchange nail should be at least 1 mm larger in diameter than the nail being removed, and it has been recommended that it be up to 4 mm larger when the nail being removed was greatly undersized. Canal reaming should progress until osseous tissue is observed in the reaming flutes. Exchange nailing is an excellent choice for aseptic nonunions of noncomminuted diaphyseal femoral fractures, with union rates reported to range from 72% to 100%. On the basis of the available literature, exchange nailing cannot be recommended for distal femoral nonunions at this time. Exchange nailing is an excellent choice for aseptic nonunions of noncomminuted diaphyseal tibial fractures, with union rates reported to range from 76% to 96%. On the basis of the available literature, exchange nailing is generally not indicated for humeral nonunions.

Ankle Injuries↗
PubMed2006

Glenoid component insertion in total shoulder arthroplasty: comparison of three techniques for drying the glenoid before cementation.

This prospective randomized study compared the immediate postoperative periglenoid radiolucencies among 3 glenoid-drying techniques used in total shoulder arthroplasty. Seventy-one consecutive patients with primary osteoarthritis underwent total shoulder arthroplasty by use of 1 prosthetic system with convex-back, keeled, polyethylene glenoid components; the same modern, instrumented pressurization technique was used to cement all glenoids. Of the shoulders, 21 had glenoid implants cemented after bony preparation with thrombin-soaked gel foam, 24 after compressed gas lavage, and 26 after saline solution lavage with sponge drying. The immediate postoperative anteroposterior radiographs were examined to evaluate the presence of periglenoid radiolucencies. Of the patients, 29 (41%) had radiolucencies evident immediately postoperatively, with all radiolucencies occurring in the faceplate zones. The mean total radiolucent line score was 0.63 (P = .94), with no significant difference among cementing preparation techniques (P = .89). Prosthetic mismatch did not differ among glenoid preparation techniques (P = .86). There was no statistical association between prosthetic mismatch and radiolucent line score either across (P = .62) or within (P = .99) the glenoid preparation groups. The associated costs in the gel foam group and compressed gas lavage group were 70 times higher than the cost in the saline solution lavage group. All radiolucencies were noted in the faceplate zones, with no radiolucency greater than 2 mm. Preparation of the glenoid surface for cementing showed no significant difference among the 3 techniques studied, although the material costs were significantly higher in the gel foam and compressed gas lavage groups compared with the saline solution lavage group.

Arthroplasty, Replacement↗
PubMed2006

Continuous femoral nerve block versus intra-articular injection for pain control after anterior cruciate ligament reconstruction.

BACKGROUND: Continuous femoral nerve blocks have been recommended for postoperative pain control after anterior cruciate ligament reconstruction. HYPOTHESIS: A pain control protocol involving a continuous ropivacaine femoral nerve block will decrease pain and narcotic use in the first 24 hours after surgery compared with a postoperative pain control protocol involving an intra-articular injection of bupivacaine/morphine. STUDY DESIGN: Randomized controlled clinical trial; Level of evidence, 2. METHODS: Ninety subjects, aged 15 years or older, who were receiving arthroscopically assisted bone-patellar tendon-bone anterior cruciate ligament reconstruction were randomly assigned to 2 groups. The first group received a ropivacaine continuous femoral nerve block and oral hydrocodone (block group). The second group received an intra-articular bupivacaine/morphine injection and oral oxycodone (injection group). Patients in both groups could receive intramuscular injection of hydromorphone for breakthrough pain; most patients in the block group also received bolus doses of ropivacaine through the femoral catheter. Subjects rated their worst, average, and current pain levels using a visual analog scale and category-ratio scale the morning after surgery. Postoperative narcotic pain medication use was converted to morphine-equivalent doses. RESULTS: Postoperative pain ratings did not differ between the treatment groups. The largest difference in pain ratings between the groups was 0.5 cm for worst pain level (P = .345). Total narcotic use did not differ significantly between groups (1.1 morphine-equivalent doses in both groups; P = .671). CONCLUSIONS: Continuous femoral block with ropivacaine appeared to have no clinical advantage in the immediate postoperative period after anterior cruciate ligament reconstruction when compared with an intra-articular injection of bupivacaine/morphine. Both methods are effective for pain control after anterior cruciate ligament reconstruction.

Administration, Oral↗
PubMed2006

Arthroscopic release of the vastus lateralis tendon for recurrent patellar dislocation.

BACKGROUND: Arthroscopic release of the vastus lateralis tendon for treatment of recurrent patellar dislocation has been criticized on the grounds that it may weaken the quadriceps. HYPOTHESIS: Quadriceps strength and outcome measures improve after arthroscopic release of the vastus lateralis tendon in patients with documented patellar dislocation. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty patients who had recurrent patellar dislocation underwent arthroscopic lateral retinacular release that included a complete release of the vastus lateralis tendon from the superior pole of the patella and were observed prospectively. Bilateral quadriceps strength was tested preoperatively and at follow-up with an isokinetic dynamometer. Patients also completed the International Knee Documentation Committee Subjective Knee Form and the Short Form-36 preoperatively and postoperatively. RESULTS: Follow-up averaged 27 months (range, 24-43 months). There were no redislocations. Mean quadriceps strength improved by a mean of 28% (from 32.3 to 41.4 N x m). The mean quadriceps torque ratio (involved/uninvolved) improved significantly from a preoperative value of 63% (31/51 N x m) to 80% (42/52 N x m) at follow-up (P = .017). Fourteen patients (70%) increased quadriceps torque, and 6 patients (30%) decreased quadriceps torque. Only 1 patient failed to improve on International Knee Documentation Committee and Short Form-36 scores. The International Knee Documentation Committee scores improved from 45 points preoperatively to 76 points at follow-up (P = .001). The Short Form-36 physical component summary scores improved from 38 points preoperatively to 50 points at follow-up (P = .007), and the Short Form-36 physical functioning subscale scores improved from 53 points to 86 points (P = .015). CONCLUSION: Arthroscopic release of the vastus lateralis tendon and lateral patellar retinaculum in patients with recurrent patellar dislocation can improve quadriceps strength and knee function.

Adolescent↗
PubMed2006

The arthroscopic square knot: a biomechanical comparison with open and arthroscopic knots.

PURPOSE: To compare the loop and knot security of arthroscopic square knots with other arthroscopic and open knots with the use of 2 commonly used suture types. METHODS: Five knot configurations were tested 12 times each. The arthroscopic square knot was compared with the open square knot, arthroscopic and open half hitches with alternating posts, and the Duncan loop. Load-to-failure testing was performed at a rate of 1.25 mm/sec, and cyclic testing was performed between 7 N and 30 N at a rate of 1 N/sec for 50 cycles. Two suture types were tested: No. 2 Ethibond suture and No. 2 FiberWire. RESULTS: Among the No. 2 Ethibond sutures, the arthroscopic Duncan loop had the highest load-to-failure at 165 N. The remaining knot types failed at between 142 N and 148 N. The load at 3 mm of lengthening was between 100 N and 120 N for all knots. The No. 2 FiberWire failed at higher loads than the No. 2 Ethibond suture for all knot types except the Duncan loop. The arthroscopic half hitches, arthroscopic square knots, and open half hitches all failed at between 220 N and 264 N. The open square knot failed at 188 N, and the Duncan loop failed at 147 N. The load at 3 mm of lengthening was between 130 N and 165 N for all knots except the Duncan loop, which failed at 95 N. With cyclic testing, arthroscopic square knots performed better than all knot types, but the differences were clinically insignificant. CONCLUSIONS: Arthroscopic square knots have the same or greater strength when compared with other arthroscopic or open knots tied with the same suture type, and they perform as well or better in the face of cyclic loads. Good knot security can be attained with all of the knots tested, regardless of suture type. Equivalent knots tied with No. 2 FiberWire fail at higher loads, except for those tied with the Duncan loop. CLINICAL RELEVANCE: Arthroscopic square knots can be used in the clinical setting with no compromise in function when compared with open square knots.

Arthroscopy↗
PubMed2006

Arthroscopic debridement in the treatment of patients with isolated tears of the subscapularis.

PURPOSE: To evaluate the treatment of properly selected patients with isolated subscapularis tears by arthroscopic debridement and release of the long head of the biceps. METHODS: Eleven shoulders that had undergone arthroscopic debridement in the treatment of subscapularis tears were reviewed. In all patients, 3 months of appropriate nonoperative management had been unsuccessful. Patients were selected for arthroscopic debridement if the tear was thought to be irreparable, or if the patient was older and unwilling to participate in the rehabilitation required after repair had been completed. Mean age at surgery was 64 years. The mean time interval from onset of symptoms to surgery was 11 months. Seven tears were traumatic, and 4 were degenerative. Four tears involved the superior third of the subscapularis tendon, 2 involved the superior two thirds of the subscapularis tendon, and 5 were complete tears. Nine shoulders also had dislocation or subluxation of the long head of the biceps tendon; these patients underwent concomitant biceps tenotomy. Patients were evaluated clinically and radiographically at a mean 34-month follow-up (range, 24 to 48 months). RESULTS: The mean Constant score increased from 49 points preoperatively to 80 points postoperatively (P < .0001). Nine patients were satisfied or very satisfied with the results. Preoperatively, 2 patients had mild glenohumeral arthritis. Postoperatively, radiographs demonstrated no progression of arthritis and no new-onset arthritis in these 2 patients. CONCLUSIONS: The combination of arthroscopic debridement and biceps tenotomy in the treatment of subscapularis tears with biceps disease in selected patients yields good objective improvement and a high degree of patient satisfaction. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Female↗
PubMed2006

Payer type has little effect on operative rate and surgeons' work intensity.

Does health-care payer type affect the rate of operative treatment and surgeons' work intensity for patients with orthopaedic conditions? We analyzed the clinical and financial data collected during 6 consecutive years (1999-2004) for a group practice of 40 orthopaedic surgeons. We examined the rate of operative treatment and surgeons' work intensity (total physician's work Resource-based Relative Value System units) by diagnosis, patient age, and payer type. The eight payer types were: capitation health maintenance organization, health maintenance organization, preferred provider organization, indemnity, self-pay, Workers' Compensation, Medicaid, and Medicare. There were 230,306 patients with 526 unique primary diagnoses. Diagnosis accounted for most of the variability in operative rates and surgeons' work intensity. After adjusting for differences attributable to diagnosis, payer type had little effect on the rate of operative treatment and surgeons' work intensity.

Adult↗
PubMed2006

Repair of tears of the subscapularis. Surgical technique.

BACKGROUND: Rotator cuff tears involving the subscapularis are less common than those involving the superior aspect of the rotator cuff. The purpose of the present study was to report the results of repair of isolated tears of the subscapularis. METHODS: The records on eighty-four shoulders that had undergone open repair of the subscapularis tendon were reviewed. The mean age of the patients at the time of surgery was 53.2 years. The mean interval from the onset of symptoms to the time of surgery was 12.5 months. Fifty-seven tears were traumatic, and twenty-seven were degenerative. Twenty-three tears involved the superior one-third of the subscapularis tendon, forty-one tears involved the superior two-thirds, and twenty tears were complete. Fifty-four shoulders had a dislocation or subluxation of the long head of the biceps tendon, and ten shoulders had a rupture of the long head of the biceps tendon. Forty-eight shoulders underwent concomitant biceps tenodesis, thirteen shoulders underwent concomitant biceps tenotomy, and four shoulders underwent concomitant recentering of the biceps. Patients were evaluated clinically and radiographically at a mean of forty-five months (range, twenty-four to 132 months) postoperatively. RESULTS: The mean Constant score increased from 55.0 points preoperatively to 79.5 points postoperatively. Seventy-five patients were satisfied or very satisfied with the result. Preoperatively, four shoulders had mild glenohumeral arthritis. Postoperatively, twenty-five shoulders had mild glenohumeral arthritis and two shoulders had moderate glenohumeral arthritis. Tenodesis or tenotomy of the biceps tendon at the time of subscapularis repair was associated with improved subjective and objective results, independent of the preoperative condition of the biceps tendon. CONCLUSIONS: Repair of isolated subscapularis tears yields acceptable improvement in shoulder function in selected patients. Additionally, the results of the present study support routine tenodesis or tenotomy of the long head of the biceps tendon at the time of subscapularis repair.

Humans↗
PubMed2005

Factors related to additional knee injuries after anterior cruciate ligament injury.

PURPOSE: We reviewed 1,375 consecutive patients to determine whether patient gender, age at injury, or activity level at injury were related to the risk of additional knee injuries over time following anterior cruciate ligament (ACL) injury. TYPE OF STUDY: Retrospective case series. METHODS: Survival analysis was used to analyze the effect of each factor while statistically controlling for the effect of time from ACL injury to reconstruction. RESULTS: The risk of meniscus injury was significantly higher among male subjects (odds ratio [OR] = 1.5, P < .001). When undergoing ACL reconstruction more than 6 months after injury, the risk of meniscus injury increased by 1.5 times for male subjects (P = .021) but increased by 3.4 times for female subjects (P < .001). The risk of meniscus injuries was significantly higher among patients undergoing ACL reconstruction more than 6 months after injury when compared with patients undergoing reconstruction within 2 weeks of injury (OR = 2.2, P < .001). The risk of articular cartilage lesions was significantly higher among patients undergoing ACL reconstruction more than 1 year after injury when compared with patients undergoing reconstruction within 2 weeks of injury (OR = 2.1, P < .001). CONCLUSIONS: Men had a consistently higher occurrence rate of meniscus injuries than did women. The risk of meniscus injuries increased at a higher rate over time among women. The risk of meniscus injuries increases when ACL reconstruction is performed more than 6 months after injury. The risk of articular cartilage lesions increases when ACL reconstruction is performed more than 1 year after injury. LEVEL OF EVIDENCE: Level IV, Case Series.

Adult↗
PubMed2005

Radiographic comparison of two glenoid preparation techniques in total shoulder arthroplasty.

We compared the prevalence of periglenoid radiolucencies between two glenoid component preparation techniques used in total shoulder arthroplasties. Seventy-two consecutive patients with primary osteoarthritis had total shoulder arthroplasties using one prosthetic system with flat-back keeled polyethylene glenoid components. Thirty-seven shoulders had glenoid implants that were cemented after standard curettage preparation of the keel slot. Thirty-five shoulders had glenoid implants that were cemented after using bone compaction to prepare the keel slot. The immediate postoperative and 2-year postoperative radiographs were examined to evaluate the presence and progression of periglenoid radiolucencies. The curettage group had a higher rate (38%) of keel radiolucencies than the compaction group (11%) seen on the immediate postoperative radiographs. Both groups had progression of periglenoid radiolucencies with time. Progression of the radiolucent lines was worse in the curettage group 2 years after arthroplasty. Preparation of the glenoid component keel slot with the bone compaction technique seems to achieve better fixation of flat-back keeled polyethylene glenoid components in total shoulder arthroplasties.

Adult↗
PubMed2005

The acromiohumeral and coracohumeral intervals are abnormal in rotator cuff tears with muscular fatty degeneration.

UNLABELLED: We sought to determine how various types of full-thickness rotator cuff tears, fatty degeneration of the rotator cuff muscles, duration of symptoms, and mechanism of injury affect the sizes of the acromiohumeral and coracohumeral intervals. We studied 206 shoulders with rotator cuff tears that had surgical treatment. The acromiohumeral interval (anteroposterior radiograph) and the coracohumeral interval (computed tomogram) were measured on preoperative imaging studies. An abnormal acromiohumeral interval was associated with multiple-tendon rotator cuff tears involving the infraspinatus, fatty degeneration of the supraspinatus or infraspinatus, and duration of symptoms longer than 5 years. An abnormal coracohumeral interval was associated with a combined tear of the supraspinatus and subscapularis and fatty degeneration of the infraspinatus or subscapularis. Fatty degeneration of the infraspinatus therefore was associated with an abnormal acromiohumeral interval and an abnormal coracohumeral interval. Evaluation of a patient who has a diminished acromiohumeral or coracohumeral interval should involve examination with computed tomography or magnetic resonance imaging of the rotator cuff tendons to determine the type of tear and of the rotator cuff muscles to determine the degree of fatty degeneration. LEVEL OF EVIDENCE: Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients--with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

Acromioclavicular Joint↗
PubMed2005

Orthopaedic surgeons do not increase surgical volume after investing in a specialty hospital.

BACKGROUND: The number of surgical specialty hospitals with physician investors in the United States has increased in the last ten years. Opponents to these hospitals have argued that surgeon investors will perform more surgery in order to maintain the hospital's profitability. The purpose of the present study was to determine whether the surgical volume or the surgical rate increased for a group of ten orthopaedic surgeons after the opening of an orthopaedic surgery specialty hospital in which they held a financial interest. METHODS: We analyzed the practice data for ten orthopaedic surgeons during an interval spanning seven years before and eight years after the opening of an orthopaedic surgery specialty hospital in which they held a financial interest. The average rates of change in the number of surgical procedures per year for each period were computed and compared with use of regression analysis. The percentages of patients who underwent surgery before and after the opening of the specialty hospital were also compared. RESULTS: The ten orthopaedic surgeons did not increase their surgical volume or surgical rate after the specialty hospital opened. The ten surgeons performed an average of 4399 surgical procedures per year before the hospital opened and 4542 surgical procedures per year after the hospital opened. The rate of change in the number of surgical procedures per year (19.1 compared with 8.9 procedures per year) did not increase after the specialty hospital opened. The annual patient volume (16,019 compared with 15,982 patients) and the percentage of patients who underwent surgery (27.5% compared with 28.4%) did not significantly change after the specialty hospital opened. CONCLUSIONS: The opening of an orthopaedic surgery specialty hospital did not increase the surgical volume or the surgical rate for ten orthopaedic surgeons who held a financial interest in the facility.

Hospitals, Special↗
PubMed2004

Comparison of two psychometric scaling methods for ratings of acute musculoskeletal pain.

Psychometric theory allows interindividual comparisons by scaling differences among subjects with respect to some psychological attribute. The most widely used psychometric scaling method is classical test theory. The properties of classical test theory pain scores are limited to the observed range of pain scores in a given sample, to the specific conditions in a given sample that are the source of pain (e.g. surgery vs. cancer), and to a particular pain survey. The reliability and meaning of classical test theory scores differ for subjects who have higher or lower amounts of pain, have different painful conditions, or are given a different pain survey. Thus, classical test theory pain scores cannot be used to compare dissimilar patient groups or painful conditions, especially if different pain surveys are used. A different psychometric scaling method, item response theory, produces scores with properties that are not limited to an observed score range, specific conditions, or a particular pain survey, and may thus be better for making such comparisons. To compare the two psychometric methods, data were obtained from 335 subjects who rated their clinical pain using 15 words. The psychometric scaling methods were compared using standardized residuals (data fit), standard errors of measurement (score precision), and a graphical plot of predicted scores against scale scores (bias). The item response theory scores demonstrated better data fit and less bias than did the classical test theory scores. In addition to superior psychometric properties, item response theory scores have several other important theoretical and practical advantages.

Adult↗
PubMed2004

Utilization of orthopaedic services for hand and wrist conditions in a capitated population.

BACKGROUND: The utilization of orthopaedic services (office visits and surgery) to treat hand and wrist conditions is not well known. In this study, we report the utilization rates for patients referred for orthopaedic treatment of hand and wrist conditions in a large population of individuals enrolled in a capitated insurance plan. METHODS: The study population consisted of individuals enrolled, between January 1998 and December 2001, in a capitated insurance plan that had an annual average membership of 135,188 during that period. This plan was serviced by an independent physician association of sixty-two orthopaedic surgeons who were responsible for all orthopaedic care. Data were collected prospectively in a centralized database as patients with various hand or wrist conditions were referred for orthopaedic services. Odds ratios were used to compare gender-specific and age-specific utilization rates. RESULTS: Overall utilization rates were 18.06 office visits and 6.47 surgical procedures per 1000 members per year. The most frequent hand or wrist conditions were fractures, carpal tunnel syndrome, tendinitis or tenosynovitis, and ganglion or synovial cysts. These four diagnoses accounted for 70% of all office visits and 71% of all surgical cases. Across all age groups, males had a significantly higher rate of utilization of office visits (p < 0.001). Between the ages of thirty-five and fifty-five years, utilization of office visits and surgery increased approximately linearly with age. CONCLUSIONS: A comparison of these data with those of previous reports indicates that approximately one of every ten patients who are referred for orthopaedic services has a hand or wrist condition, and nearly half will require surgery.

Adolescent↗
PubMed2004

The incidence of fractures and dislocations referred for orthopaedic services in a capitated population.

BACKGROUND: The purpose of this study was to determine the annual incidence rates of non-work-related traumatic fractures and dislocations (excluding head and facial injuries) referred for orthopaedic services in a large population enrolled under a capitated insurance contract. METHODS: The number of fractures and dislocations that were referred for orthopaedic services were recorded prospectively from among an average of 135,333 persons per year who were enrolled under a capitated insurance contract during the three-year study period. These data were used to determine the gender-specific and age-specific incidence rates of fractures and dislocations referred for orthopaedic services. RESULTS: A total of 3440 fractures and 422 dislocations were referred for orthopaedic services during the three-year study period. The incidence rate of fractures referred for orthopaedic services was 8.47 per 1000 member-years, with a significantly (p < 0.0001) higher rate among males. Members between the ages of ten and fourteen years had the highest rate of fractures referred for orthopaedic services (21.52 per 1000 member-years). The lifetime risk of a traumatic fracture referred for orthopaedic services to the age of sixty-five years was one in two for both males and females. The incidence rate of dislocations referred for orthopaedic services was 1.04 per 1000 member-years, which did not differ significantly (p = 0.75) between genders. Members between the ages of fifteen and nineteen years had the highest rate of dislocations referred for orthopaedic services (2.75 per 1000 member-years). The lifetime risk of a traumatic dislocation referred for orthopaedic services to the age of sixty-five years was one in sixteen for both male and female members. CONCLUSIONS: Young males had the highest rate of traumatic fractures referred for orthopaedic services. Adolescents of both genders had high rates of traumatic dislocations referred for orthopaedic services. The lifetime risk of a non-work-related fracture referred for orthopaedic services to the age of sixty-five years is approximately equal to that of coronary artery disease.

Adolescent↗
PubMed2004

Bilateral femoral neck fractures after pelvic irradiation.

Our patient, who had no history of trauma, developed bilateral femoral neck fractures several years after pelvic irradiation. The well-documented sequelae of femoral neck fractures include avascular necrosis, nonunion, and malunion. Postirradiation pelvic pain, particularly in the absence of trauma, should be aggressively evaluated. With high clinical suspicion and normal plain radiographs, MRI can be used to exclude potentially serious fractures.

Aged↗