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Biomedical subjects

R L Barrack

Publications and source records attributed to R L Barrack.

At least 109 records · Page 6Linked to original sources
PubMed1990

The outcome of nonoperatively treated complete tears of the anterior cruciate ligament in active young adults.

The results of nonoperative treatment of 72 patients with complete anterior cruciate ligament (ACL) tears, documented by examination under anesthesia and arthroscopy, were evaluated. All patients had an acute injury with hemarthrosis in a previously normal knee. Patients having meniscal repair were excluded as were those with collateral or posterior cruciate ligament tears or associated fractures. Treatment in all cases consisted of a standard protocol of early rehabilitation and bracing. A detailed rating of symptoms and function was performed at an average of 38 months postinjury (range, eight to 84 months). Overall results were 11% excellent, 20% good, 15% fair, and 54% poor. Thirty-five percent had ACL reconstruction during the follow-up period. Results indicate that young adults who return to a vocation requiring strenuous physical activity frequently can expect unsatisfactory results after nonoperative treatment of an acute complete tear of the ACL.

Adolescent↗
PubMed1990

A technique of acetabular reconstruction for uncemented total hip replacement.

A technique for performing uncemented total hip replacement in the presence of osteoarthritis with proximal femoral migration is detailed. The femoral head is used as an autograft. The center of rotation of the hip is returned to its anatomic location, and subchondral bone is preserved. Rigid fixation of the graft is accomplished with matching reamers and AO lag screw fixation. Simultaneous reaming of graft and host bone produces a seamless transition to ensure graft loading. The goals of restoration of anatomic hip center, rigid press fit, and complete cup coverage are accomplished.

Acetabulum↗
PubMed1989

Quantitative histologic analysis of tissue growth into porous total knee components.

Histologic and radiographic analysis was performed on 85 porous-coated, uncemented knee components (26 femoral, 34 tibial, and 25 patellar) retrieved from 45 patients for malposition or instability, unexplained pain, late infection, postmortem or postamputation, and posttrauma. No component was clinically or radiographically loose at the time of removal. The average patient age at removal was 62.1 years (range, 39-85 years), and the average time in situ was 12.4 months (range, 2 weeks to 53 months). Radiographs from 31 of the 45 patients (69%) were examined for implant alignment, fit, subsidence, loose beads, and the presence of sclerotic and lucent lines. Histologic and microradiographic sections of the implant and adherent tissue were examined for type, amount, and anatomic location of tissue ingrowth. Overall, 52% of the components showed no evidence of bone ingrowth, 29% showed minimal (less than 2%), 12% showed moderate (2-5%), and 7% showed extensive (5-10%) bone ingrowth. In no case was bone present in more than 10% of the available pore volume of any component. There were no significant differences in the incidence or extent of bone ingrowth among femoral, tibial, and patellar components, nor in the extent of bone ingrowth observed in comparing different implant designs, materials, or porous coating types. When bone ingrowth was observed, the anatomic location was consistent in each type of component. The presence of a lucent line radiographically was indicative of fibrous encapsulation, while a sclerotic line or absence of any radiographic abnormality was seen with both fibrous tissue and bone ingrowth.

Aged↗
PubMed1989

Arthroscopy in patients with recalcitrant retropatellar pain syndrome.

The purpose of this study was to determine the arthroscopic findings in patients with recalcitrant retropatellar pain syndrome (RPPS) and correlate them with the patient's long-term clinical course. All patients undergoing arthroscopy for recalcitrant retropatellar pain syndrome were evaluated. Patients were excluded from the study if there was any history consistent with a meniscal or cruciate injury or if they had previously had knee surgery. Long-term follow-up was obtained in 41 of 81 patients (51%) (range, 24 to 73 months; mean, 51 months). The arthroscopic findings were recorded, and the status of chrondral surfaces graded and correlated with clinical ratings, which utilized a modification of the Insall rating system. Debridement of cartilage irregularities was performed routinely. At follow-up, nearly equal numbers of patients improved, stayed the same, or got worse. No correlation was seen between the findings at arthroscopy and the long-term results. Debridement of cartilage lesions was not found to be beneficial as a treatment modality. Missed intra-articular pathology was found at arthroscopy in only two (4%) of the 81 patients. Based on this study, conservative treatment remains the treatment of choice.

Adult↗
PubMed1989

Scapular osteomyelitis. An unusual complication following subacromial corticosteroid injection.

Impingement syndrome is a common disorder of the shoulder. Most patients respond to conservative treatment consisting of rest, ice/heat, anti-inflammatory agents, and physical therapy. Subacromial corticosteroid injection may be used when other forms of conservative treatment fail. A case is reported involving a 29-year-old man who developed scapular osteomyelitis following subacromial corticosteroid injection. Successful treatment consisted of surgical debridement followed by a combination of intravenous and oral antibiotic therapy. Strict adherence to aseptic technique is emphasized for performing subacromial corticosteroid injection.

Adrenal Cortex Hormones↗
PubMed1988

Arthroscopic treatment of acute patellar dislocations.

Twenty-nine patients treated with arthroscopy alone for acute patellar dislocation were reviewed. All had a significant traumatic episode with hemarthrosis in a previously asymptomatic knee. Clinical follow-up averaged 25 months (range 5-64 months). Fifteen patients had concomitant percutaneous lateral release (LR). Significant-sized osteochondral defects not radiographically visible preoperatively were discovered in 40%. Fragments were excised and corresponding craters debrided or abraded. Additional intraarticular pathology discovered included two meniscal tears and one anterior cruciate tear. Overall excellent (E) and good (G) results were 83%. The recurrence rate was 14%, all of which occurred in the LR group. All recurrent dislocations occurred within 1-year post injury. The LR group had 73% G and E results compared with 93% in those without LR. Arthroscopy followed by immobilization was an efficacious approach to acute traumatic patellar dislocations in this specific group of patients. The addition of LR with early motion, however, detracted from the results.

Acute Disease↗
PubMed1988

Quantitative analysis of tissue growth into human porous total hip components.

Histologic and radiographic analysis was performed on 36 porous-coated total hip components (22 femoral and 14 acetabular) retrieved from 30 patients. The average patient age was 53.0 years (range, 28-78 years) for femoral components and 56.9 years (range, 28-78 years) for acetabular components. The average time in situ was 13.6 months (range, 2-36 months) for femoral components and 5.5 months (range, 1-18 months) for acetabular components. Fourteen implants were retrieved for instability or dislocation, 12 for late infection, and 8 for persistent pain, and 2 were retrieved after the patient died. Radiographs were reviewed for Singh index, heterotopic bone, implant fit, subsidence, and presence of lucent and sclerotic zones. Histologic and microradiographic sections of the implant and adherent tissue were examined for type, amount, and anatomic distribution of tissue ingrowth. Four femoral stems had no bone ingrowth, 10 had minimal bone growth into the available pore volume (less than 2%), 3 had moderate bone ingrowth (2-5%), and 5 had more extensive bone ingrowth (5-10%). Bone ingrowth tended to occur where the implant made direct contact with the endosteal cortical surface and was rarely seen in proximal metaphyseal bone. Bone ingrowth was completely absent in eight acetabular components, minimal (less than 2%) in three, moderate (2-5%) in two, and more extensive (5-10%) in one and tended to occur adjacent to fixation pegs, spikes, or screws. Radiographic or clinical findings were unreliable in predicting the presence or extent of bone ingrowth in either femoral or acetabular components.

Acetabulum↗
PubMed1988

Triplane fracture of the distal tibial epiphysis. Long-term follow-up.

The cases of twenty-three patients in whom a triplane fracture had been treated at the Naval Hospital, Oakland, California, between 1974 and 1985, were reviewed. The anatomical configuration of the fracture was confirmed in fifteen patients. Eleven of the fifteen patients had a three-fragment fracture. Plain radiographs alone did not accurately demonstrate the configuration of the fracture. Twenty patients were asymptomatic when they were evaluated eighteen to thirty-six months after the injury, but only eight of fifteen patients were asymptomatic when they were evaluated thirty-eight months to thirteen years after the fracture. Residual displacement of two millimeters or more after reduction was associated with a less than optimum result unless the epiphyseal fracture was outside the primary weight-bearing area of the ankle.

Adolescent↗
PubMed1986

Effect of fatigue on joint position sense of the knee.

This study was designed to test position sense of the knee joint before and after fatigue in order to determine whether muscle or capsular receptors are the primary sensors for joint position sense. Reproduction of passive positioning and detection of the onset of motion (kinesthesia) were employed to measure joint position sense. Eleven subjects underwent joint position sense measurement before and after a fatigue protocol. A significant worsening of reproduction of knee joint angle after fatigue was noted (p less than 0.05). Threshold (kinesthesia) showed no statistically significant change after fatigue. A significant correlation of reproduction measurements and threshold measurements prior to fatigue (p less than 0.01) demonstrated that the same neural mechanism is applicable in the rested state, but these variables did not correlate significantly after fatigue. There was a significant correlation between reproduction measurements before and after fatigue (p = 0.018), while no correlation was seen for the pre- and postfatigue threshold measurements, suggesting a change in the neural path after fatigue. Since both tests of joint position sense are affected by fatigue, we conclude that muscle receptors are a prominent, if not primary, determinant of joint position sense, and capsular receptors may have a secondary role. Reproduction ability is decreased, presumably through the loss of efficiency of muscle receptors. The threshold data suggest a change in the mechanism of appreciation after fatigue, possibly due to increased sensitivity of capsular receptors from muscle-fatigue-induced laxity.

Adult↗
PubMed1986

Vibratory response in idiopathic scoliosis.

Recent clinical studies have suggested that a neurological lesion may be a cause of adolescent idiopathic scoliosis and animal experiments have implicated the posterior column pathway. We have tried to determine if differences in neurological response could be detected and measured clinically, and have compared the threshold of detection of vibratory sensation in 20 girls with adolescent idiopathic scoliosis with that in 20 clinically normal age-matched controls. A highly significant reduction of the threshold of detection of vibration was seen in the scoliotic group compared to the controls (p less than 0.001). Curve magnitude did not correlate with this threshold for either the upper (r = 0.172) or lower extremity (r = 0.126). Significant asymmetry between right- and left-sided thresholds to vibration was demonstrated in the scoliotic group. Our study supports the concept that an aberration in the function of the posterior column pathway of the cord may be of primary importance in the aetiology of idiopathic scoliosis. A clinically practical test to measure this function is presented.

Adolescent↗
PubMed1986

CT scan helps delineate cervical osteoid osteoma and atypical nidus.

Computerized tomography proves to be particularly helpful in anatomically delineating an osteoid osteoma of the spine in an inaccessible area and in also identifying an atypical nidus. A case is presented of an 8-year-old boy with a one-year history of pain in the right shoulder and neck. Computerized tomography accurately delineated in anatomic detail the lesion along with an atypical nidus adjacent to the spinal canal, thus assuring total excision of both lesions. The patient regained normal neck and shoulder motion with no recurrence of pain.

Cervical Vertebrae↗
PubMed1986

Upper extremity proprioception in idiopathic scoliosis.

Twenty-three patients with idiopathic scoliosis were tested for upper extremity proprioceptive function. All subjects had documented progression of deformity, with an average curvature of 34 degrees. The average ages for scoliotics and 18 control subjects were 16.1 and 20.8 years, respectively. Controls had no spinal deformity and underwent identical test procedures. The test results showed that scoliotic subjects had significant asymmetry between right and left limbs in their threshold for detection of joint motion (p less than or equal to 0.005) and in their ability to reproduce angles to which their elbow joint had been previously positioned (p less than or equal to 0.025). Slight asymmetry also was observed in the reproduction tests of the control group (p less than or equal to 0.013); however, there was no significant asymmetry seen in this group for the threshold test. Performance of bilateral limbs was designated good and bad for both groups; the limb that performed better in proprioceptive function was designated good limb. Analysis of data showed that the scoliotics' good and bad limbs performed inferiorly in both threshold and angle reproduction tests when compared with normal controls. The results of this study imply, but do not localize, a neurologic deficit in scoliotic patients.

Adolescent↗
PubMed1985

An analysis of failed Harrington rods.

Eight mechanically failed Harrington rods have been retrieved and examined clinically, metallurgically, and biomechanically to characterize the mode of instrument failure and to determine how future failure rates might be minimized. The results of the study indicated fatigue to be the mode of mechanical failure in all cases, however, in only one case was any significant metallurgical defect observed. Failure occurred at the ratchet-shaft junction in seven of eight cases with the remaining failure occurring at the midshaft region. This occurred in the rod with the metallurgical defect. The possibility of fatigue failure can be lowered by implementing both clinical and design considerations. Clinically, stress on the rod can be lowered by placing the ratchet-shaft junction as close to the hook as possible and by using the shortest rod possible. Both of these will minimize the moment arm at the vulnerable ratchet-shaft junction. Design modifications, including increased rod diameter, polishing the ratchet-shaft interface and material changes, can also be used to lower the stress on the rods and thus reduce the risk of mechanical failure.

Equipment Failure↗
PubMed1985

Clinical and metallurgical analysis of retrieved internal fixation devices.

The clinical performance, corrosion characteristics, and metallurgical properties of 82 retrieved stainless-steel bone plates have been examined. The plates had been in situ for periods ranging from one to 169 months. Only 29% of these devices (24 of 82 plates) were removed on a routine asymptomatic basis, while 62% (51 of 82 plates) were removed for cause-related reasons such as implant-related pain, infection, nonunion or malunion, and so forth; seven plates were removed for unknown reasons. Although most patients who had plates removed for pain reported some improvement in symptoms, others felt no improvement after removal. On examination, over 89% of the recovered implants displayed some degree of either surface (pitting) or screw-plate interface (crevice and fretting) corrosion or both. Statistical analyses revealed that the metallurgical properties of grain size and nonmetallic inclusion content correlated significantly with the degree of both types of corrosion.

Bone Plates↗
PubMed1984

Joint position sense in total knee arthroplasty.

Seventeen postoperative total knee arthroplasty (TKA) patients were evaluated using two tests of knee joint position sense. Young controls and age-matched controls underwent identical tests. The TKA patients also underwent gait analysis, including foot switch stride analysis, and clinical evaluation using a standard scoring system. Results showed statistically significant decreases in joint position sense from young controls to old controls, and further significant decreases with joint disease; however, no further worsening was noted as a result of TKA. The abnormal gait parameters seen in TKA patients correlated as well with position sense as with clinical score. Strongest correlations were seen when a combined clinical and proprioceptive score was compared with gait parameters. In spite of alleviation of pain and correction of deformity, normal gait and function are not typically achieved after total knee replacement. Irreversible loss of joint proprioceptive function due to the disease process may be a major factor in the discrepancy between clinical and functional outcomes of total joint arthroplasty. Furthermore, loss of proprioception and the resulting abnormal gait patterns may place increased stress on components and contribute to loosening. In addition, an association between degenerative joint disease and decline in proprioception is suggested.

Adult↗
PubMed1984

Proprioception in idiopathic scoliosis.

Proprioception testing and gait analysis was performed on a group of 17 patients with idiopathic scoliosis. All curves had documented progression. The average curve was 26.8 degrees, all primary curves being right thoracic. The average age was 14.8 years. Twelve, healthy, age-matched controls underwent identical testing. Results showed that scoliotic subjects had asymmetry in their ability to reproduce angles between their two knees, as well as an absolute deficit in their ability to reproduce angles as compared with controls (P less than 0.01). The threshold of detection of change in angle at the knee was also quantitatively higher than controls (P less than 0.05), although asymmetry was not statistically significant. No significant differences were measured in gait parameters between scoliotics and controls. These joint position tests have been applied previously to young and elderly adults, athletes, and total joint patients. In no group has any asymmetry of response been demonstrated, both extremities showing virtually identical performance in each case. The tests administered measure sensory modalities, which are conducted through the posterior columns. Although the site of damage in the neural pathway cannot be specifically localized by these tests, results of this study support the presence of a neurologic deficit in idiopathic scoliosis.

Adolescent↗