Biomedical subjects

D C Wascher

Publications and source records attributed to D C Wascher.

12 recordsLinked to original sources

PubMed2001

A comparison of operative times in arthroscopic ACL reconstruction between orthopaedic faculty and residents: the financial impact of orthopaedic surgical training in the operating room.

There is no published data regarding the financial impact of training orthopaedic residents in the operating room. No comparisons between orthopaedic faculty and residents in regard to operative time and costs are known. One hundred eleven cases of anterior cruciate ligament reconstruction with or without partial meniscectomy were evaluated from 1996 to 1997. Fifty-three cases met the selection criteria of times, documentation and identification of the surgeon. Twenty-one cases were performed by the orthopaedic attending (RCS) while 32 cases were performed by the senior orthopaedic resident. All procedures had the same faculty member present in the operating room either as the primary surgeon or as an assistant providing supervision and instruction as needed. In a two year period, comparisons were made between the attending and residents for the total anesthesia time and actual operative case time. Attending case time and anesthesia times averaged 94.62 minutes (range 60-125 min) and 128.1 minutes (range 84-185 min) respectively. Resident case and anesthesia times averaged 137.09 minutes (range 95-210 min) and 190.48 minutes (range 145-255 min) respectively. The anesthesia time was significantly less for the attending (p<.0001) as was the case time (p<.0001). The true costs of training orthopaedic surgery residents in the operating room is not known. The operative time and subsequent cost difference between experienced faculty and orthopaedic residents in certain arthroscopic procedures is not inconsequential. On average, the difference is equivalent to $228.73 per case for anesthesia costs. Based on increased operative times, operating room costs, on average, were increased by $661.85. The significant differences demonstrated between residents and faculty suggest the need to develop strategies and technical training facilities in order to improve orthopaedic residents' surgical skills and efficiency outside of the cost-central operating room.

Adult↗

PubMed2000

High-velocity knee dislocation with vascular injury. Treatment principles.

A high-velocity knee dislocation is a true orthopedic emergency. A high index of suspicion is necessary to identify reduced knee dislocations in multiple trauma patients. Coexisting injuries are common in patients with high-velocity knee dislocations. After an initial assessment, the knee joint should be reduced immediately and splinted. Popliteal artery injury is common in high-velocity dislocations. Arteriograms can be helpful but should not delay operative treatment of obvious arterial injuries. Early restoration of flow to the ischemic limb will avoid amputation in most patients. The orthopedic surgeon must consider a variety of approaches when treating a patient with this type of injury. A spanning external fixator is a useful method for temporary immobilization in knee dislocation patients who have open dislocations, arterial repairs, or closed head injuries. Early surgery to improve the functional stability of the knee must be balanced against the risk of major surgery in patients with severe lower extremity and systemic injuries. The long-term risk of knee stiffness versus instability must be considered. Selective, subacute, aggressive collateral ligament repair and bicruciate reconstruction with allografts offer the best chance for optimal outcome.

Angiography↗

PubMed1999

Elbow ligament strain under valgus load: a biomechanical study.

This study assessed the importance of the anterior and posterior bundles of the medial collateral ligament in the elbow by measuring in situ strain in response to valgus loads at three positions of forearm rotation throughout a full arc of motion. Strain in the anterior bundle was significantly greater than in the posterior bundle and increased with more flexion. The anterior bundle developed strain at a lower flexion angle (30 degrees) than the posterior bundle (60 degrees). Strain ratio increased with load increase for all flexion angles. Forearm position minimally affected strain. These results indicate that the anterior bundle is important in resisting a valgus load, particularly in mid-flexion, while the importance of the posterior bundle increases as the elbow approaches full flexion.

Adult↗

PubMed1998

Reconstruction of chronic rupture of the extensor mechanism after patellectomy.

Chronic extensor mechanism ruptures are uncommon but challenging clinical problems. Previously published procedures for treating chronic extensor mechanism ruptures assume an intact patella is available to anchor the repair. A case is presented of a patient who had a previous patellectomy, followed by rupture of the extensor mechanism. After two failed attempts at repair, an Achilles tendon allograft was used successfully to restore function of the extensor mechanism. The described technique offers an alternative for reconstruction of the extensor mechanism after patellectomy.

Achilles Tendon↗

PubMed1997

Knee dislocation: initial assessment and implications for treatment.

OBJECTIVE: To evaluate bicruciate knee injuries and determine whether they should be treated as knee dislocations, especially with regard to vascular injuries. DESIGN: Retrospective. SETTING: University hospital, level 1 trauma center. PATIENTS: Fifty patients admitted between 1987 and 1994 who had sustained knee dislocations or bicruciate ligament injuries. MAIN OUTCOME MEASURES: Mechanism of injury, direction of dislocation, knee ligament injury pattern, presence or absence of periarticular fracture, presence of vascular and nerve injuries, and location of associated trauma were measured. RESULTS: Twenty-two knees had classic knee dislocations. Twenty-eight knees presented as "reduced" bicruciate ligament injuries. Vascular injury occurred just as frequently in bicruciate ligament injuries as in knee dislocations. The direction of the knee dislocation did not predict ligament injury pattern or the presence of arterial injury. CONCLUSION: Bicruciate ligament injuries are equivalent to knee dislocations with regard to mechanism of injury, severity of ligamentous injury, and frequency of major arterial injuries.

Adolescent↗

PubMed1993

Direct in vitro measurement of forces in the cruciate ligaments. Part I: The effect of multiplane loading in the intact knee.

Specially designed load-transducers that measured the resultant forces exerted by the posterior and anterior cruciate ligaments on their respective femoral and tibial insertions were applied to eighteen fresh-frozen cadaveric knees for a series of controlled loading experiments. The mean force in the posterior cruciate ligament at 5 degrees of forced hyperextension of the knee was 23 per cent of the mean force in the anterior cruciate ligament. When the knee was hyperflexed by application of 10.0 newton-meters of bending moment to the tibia, the mean force in the posterior cruciate ligament was 55 per cent of that in the anterior cruciate ligament. Quadriceps tendon pull increased the force in the posterior cruciate ligament in twelve of the fourteen specimens to which it had been applied, at 80 and 90 degrees of flexion only. The force generated in the posterior cruciate ligament by applied internal tibial torque was greatest when the knee was in 90 degrees of flexion; the force in the anterior cruciate ligament was greatest when the knee was fully extended. External tibial torque generated force in the posterior cruciate ligament in only eight specimens, and only at 80 and 90 degrees of flexion. The levels of force that were generated in the posterior cruciate ligament by applied varus and valgus bending moment were greatest at 90 degrees of flexion of the knee; the levels of force in the anterior cruciate ligament were greatest with the knee in full extension. With the knee flexed 90 degrees and the tibia in neutral rotation, fifty newtons of applied posterior tibial force increased the mean force in the posterior cruciate ligament by 58.4 newtons; at full extension, no increase in the force in the ligament was recorded, indicating that tensed capsular structures were absorbing the applied load. When the tibia was internally or externally rotated by applied tibial torque, the increases in the force in the ligament from applied posterior tibial force were sharply diminished.

Aged↗

PubMed1993

Direct in vitro measurement of forces in the cruciate ligaments. Part II: The effect of section of the posterolateral structures.

Specially designed load-transducers were applied to eight fresh-frozen cadaveric knee specimens in order to measure resultant forces in both cruciate ligaments as the knees were subjected to straight varus-valgus bending moment and to tibial torque (with and without a superimposed posterior tibial force). The forces in the ligaments and tibial rotation were recorded at seven angles of flexion of the knee, between 0 and 90 degrees, before and after section of the posterolateral structures. Ligamentous section increased angulation of the tibia when varus moment was applied to the knee; the large increases in lateral opening of the knee joint were accompanied by increases in the force in the anterior cruciate ligament at all angles of flexion and increases in the force in the posterior cruciate ligament between 45 and 90 degrees of flexion. When valgus moment was applied, there were no significant changes in valgus angulation or the resultant force in either cruciate ligament after ligamentous section. Ligamentous section increased rotation of the tibia when external torque was applied to the knee. The increased external rotation was accompanied by decreases in the force in the anterior cruciate ligament between 0 and 20 degrees of flexion of the knee and increases in the force in the posterior cruciate ligament between 45 and 90 degrees of flexion. In the studies involving applied internal tibial torque, after ligamentous section, rotation of the tibia increased slightly between 60 and 90 degrees of flexion. The force in the anterior cruciate ligament increased between 0 and 20 degrees of flexion, while the force in the posterior cruciate ligament was unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMedDate not supplied

Coccidiomycosis presenting as a popliteal cyst.

Coccidiomycosis is a fungal infection that primarily causes pulmonary disease. Extrapulmonary dissemination can occur to the musculoskeletal system with the knee joint most frequently involved. This case report describes a patient with coccidiomycosis whose initial presentation was of a popliteal cyst. The need for aggressive surgical and antibiotic treatment to eradicate this infection is discussed. Coccidiomycosis should be considered in a differential diagnosis of patients with popliteal cysts without other obvious etiologies.

Adult↗

PubMedDate not supplied

Septic arthritis following arthroscopic meniscus repair: a cluster of three cases.

Three cases of Staphylococcus epidermidis septic arthritis following inside-out arthroscopic meniscus repair within a 4-day period at the same facility are described. All three patients responded to surgical debridement and 4 to 6 weeks of intravenous antibiotics. In each instance, the meniscus and repair sutures were left intact; 12- to 38-month follow-up revealed no evidence of infection or meniscal symptoms. Epidemiological investigation implicated the meniscus repair cannulas as one of the few factors common to all three cases. Molecular typing of bacterial DNA revealed that two of the three isolated organisms showed identical pulsed-field gel electrophoretic patterns, implying a common source of inoculation. Experimental contamination of the cannulas revealed that only sterilization involving ultrasonification, lumen washing by water jet, and steam sterilization resulted in clean and sterile cannulas.

Adult↗

PubMedDate not supplied

Biceps tendon tenodesis for posterolateral instability of the knee. An in vitro study.

The effects of biceps tendon tenodesis on internal-external and varus-valgus laxity were measured using fresh-frozen cadaveric specimens that had undergone sequential sectioning of the posterolateral structures and of the fibular collateral ligament. Tenodesis (using 89 N graft tension and a fixation point located 1 cm anterior to the fibular collateral ligament's insertion on the femur) was effective in restoring external rotation and varus laxity; the procedure actually overconstrained external tibial rotation at all flexion positions and varus angulation at 60 degrees and 90 degrees of flexion. Internal rotation and valgus laxity were unaffected by the tenodesis procedure. The anterior fixation point was more effective in reducing laxity than a fixation point located 1 cm proximal to the fibular collateral ligament insertion. Tenodesis using the proximal fixation point, which was nonisometric, did not restore external rotation and varus laxities to intact values at 60 degrees and 90 degrees of knee flexion. Graft tension (45 or 89 N) had no measurable effect on the results of the tenodesis. This study has demonstrated that the biceps tenodesis procedure is effective for reducing static laxity in the knee with posterolateral instability.

Biomechanical Phenomena↗

PubMedDate not supplied

Rupture of Lisfranc's ligament in athletes.

Ligamentous injuries to the tarsometatarsal joints are uncommon and usually result from violent trauma to the forefoot. A more subtle tarsometatarsal injury consisting of an isolated diastasis of the first and second tarsometatarsal rays has recently been described. This injury is thought to be caused by a rupture of Lisfranc's ligament. Nine injuries that occurred during athletics are described. History and physical findings are crucial for arousing the clinician's suspicion for this injury, but confirmation can best be obtained by comparison weight-bearing radiographs; the space between the first and second metatarsal bases may be widened 2 to 5 mm. Nonoperative treatment consisting of casting and the use of crutches for 4 to 6 weeks was successful in returning patients back to athletics; however, the time to return to competition averaged 4 months.

Adolescent↗

PubMedDate not supplied

Reconstruction of the anterior and posterior cruciate ligaments after knee dislocation. Results using fresh-frozen nonirradiated allografts.

We reviewed the results in 13 patients who underwent simultaneous allograft reconstruction of both the anterior and posterior cruciate ligaments after a knee dislocation (nine acute and four chronic injuries). Seven patients sustained related medial collateral ligament injuries and six patients had posterolateral complex injuries. Ligament reconstructions were performed using fresh-frozen Achilles or patellar tendon allografts. At follow-up evaluation (mean of 38 months), only one patient described the reconstructed knee as normal. Six patients had returned to unrestricted sports activities and four had returned to modified sports. The average extension loss was 3 degrees (range, 0 degree to 10 degrees) and average flexion loss was 5 degrees (range, 0 degree to 15 degrees). The KT-1000 arthrometer measurements at 133 N anterior-posterior tibial load showed a mean side-to-side difference of 4.5 mm (range, 0 to 10) at 20 degrees and 5.0 mm (range, 0 to 9) at 70 degrees. The mean Lysholm score was 88 (range, 42 to 100). International Knee Documentation Committee ratings were six nearly normal, five abnormal, and one grossly abnormal. Two patients required manipulations for knee stiffness. This study demonstrates that reconstruction of both cruciate ligaments can restore stability sufficient to allow sports activity in most patients with knee dislocations, but "normal" results are difficult to achieve.

Adolescent↗