Biomedical subjects

R L Barrack

Publications and source records attributed to R L Barrack.

At least 91 records · Page 5Linked to original sources

PubMed1994

Corrosion and wear at the modular interface of uncemented femoral stems.

We examined 108 uncemented femoral stems with modular femoral heads which had been retrieved for reasons other than loosening. There were detectable amounts of wear and corrosion in 10 of 29 (34.5%) mixed-alloy components and 7 of 79 (9%) single-alloy components after a mean implantation time of 25 months. We found no correlation between the presence or extent of corrosion or surface damage and any of time in situ, initial diagnosis, reason for removal, age, or weight. Stems with wear and corrosion were less likely to show histological bony ingrowth. The interface between the head and stem of modular total hip components is a possible source of ion release and wear debris, but wear and corrosion were totally absent in most specimens. This suggests that this problem could be avoided, and that further research is required to develop manufacturing methods which would minimise such changes.

Cementation↗

PubMed1993

Bone ingrowth into a porous-coated total shoulder component retrieved postmortem.

An uncemented porous-coated humeral component, which functioned in vivo for over 2 1/2 years, was retrieved postmortem and examined histologically. Radiographs of the specimen revealed close approximation to the endosteal cortex medially and laterally. Apposition was limited or absent anteriorly and posteriorly. The overall extent of bone ingrowth was approximately 11% of the available pore volume with over 95% of ingrowth occurring in the medial and lateral quadrants. Bone ingrowth was limited anteriorly and posteriorly to regions in which spot welds were identified radiographically. There were no loose beads or coating failure observed.

Adult↗

PubMed1993

Complications related to modularity of total hip components.

We report complications from the use of modular components in 20 hip replacements in 18 patients. Fifteen complications (in 13 patients) were related to failure of a modular interface after operation. Femoral head detachment from its trunnion was seen in 6 hips from trauma (3), reduction of a dislocation (2), and normal activity (1). In one case the base of the trunnion fractured below an extra-long modular head. In seven other hips the modular polyethylene liner dislodged from its shell, causing severe damage to the shell in four cases with extensive metallosis. In one other hip an asymmetrical polyethylene liner rotated, resulting in impingement of the femoral component and recurrent dislocation. Operative errors were seen in five cases: implantation of a trial acetabular component in one; and mismatching between the size of the femoral head and the acetabular component in the others. Surgeons who use hip replacements with modular components should be aware of the potential for operative error and of the importance of early treatment for postoperative mechanical failure.

Adult↗

PubMed1993

The value of aspiration of the hip joint before revision total hip arthroplasty.

The role of aspiration of the hip joint before revision of a total hip arthroplasty remains controversial. To address this issue, we reviewed the results of 270 consecutive hips in which aspiration had been attempted before revision procedures that were performed between 1980 and 1988. All hips had intraoperative findings and clinical follow-up of at least two years to confirm the presence or absence of infection. Only six (2 per cent) of the 270 hips were determined to be infected. Aspiration had been attempted in all six hips, but fluid could be obtained from only four. All six hips also had clinical or radiographic signs, or both, of infection, including increasing pain within three years after the arthroplasty (four hips), inability of the patient to attain pain-free status after the original procedure (four hips), radiographic findings compatible with infection (six hips), and a positive finding on culture of a specimen obtained from a previous aspiration (two hips). Because of these factors, aspiration was attempted a second time in four of the six hips and a third time in three of the four. The four hips from which fluid could be obtained had a total of ten successful aspirations; the cultures of specimens obtained from six of these procedures were positive and those from four were negative. The appearance of the capsular tissue at the time of the operation suggested infection in five of the six infected hips. Histological sections were positive for inflammation in all six: there was acute inflammation only in one, chronic inflammation only in two, and acute and chronic inflammation in three. No organisms were seen on gram stains of specimens from any of the six infected hips. Of the 254 hips that did not have an infection and had been aspirated successfully, thirty-two (13 per cent) had a false-positive result on culture of a specimen of the aspiration fluid. Only two (6 per cent) of the thirty-four hips that had a positive result on culture of fluid from the initial aspiration had a true-positive result. No hip had a true-positive result on culture of fluid that had been aspirated preoperatively without also having clinical and radiographic evidence of infection. On the basis of these findings, we recommend that aspiration be performed in selected patients rather than routinely. It also should be performed only if a detailed clinical history suggests infection or if radiographs demonstrate focal lysis, aggressive non-focal lysis, or periostitis.

Aged↗

PubMed1993

Radionuclide imaging of the knee with chronic anterior cruciate ligament tear.

We studied the results of bone scans in 50 consecutive patients with symptomatic, unilateral, chronic anterior cruciate ligament (ACL) tears. All patients had failed conservative therapy and underwent radionuclide imaging of the knee prior to arthroscopic ACL reconstruction. The scintigraphic activity in each of the three knee compartments was quantitatively scaled from 1 (normal scintigraphic activity) to 4 (marked activity). Quantitative activity in each of the three compartments was correlated with plain radiographic, arthroscopic, and clinical findings. All but four of the scans (92%) showed abnormal scintigraphic activity. The quantitative activity was highest overall in the medial compartment (2.9), followed by the lateral (2.4) and patellofemoral compartments (1.9). In the subgroup of patients with normal menisci (10 patients), most of the abnormal activity was in the lateral compartment (2.9), implying that when the medial meniscus remains competent in the presence of a torn ACL, there is increased stress on the lateral compartment. There was little correlation with scintigraphy and roentgenographic changes, except in the presence of moderate or severe radiographic degenerative arthritis. Similarly, there was little correlation between increased scintigraphic activity and chondromalacia. These results provide a baseline for future studies that use scintigraphic imaging in monitoring restoration of bone homeostasis following ACL reconstruction.

Adolescent↗

PubMed1993

Contemporary algorithms for evaluation of the painful total hip replacement.

Current data on the interpretation of nuclear medicine scans following total hip replacement are reviewed along with a new diagnostic test--the dynamic computed tomographic scan. Intraoperative diagnostic tests include frozen section, Gram's stain, and mechanical testing. This information is consolidated with that previously presented into a series of algorithms for evaluating the painful total hip replacement.

Algorithms↗

PubMed1993

Developments in diagnosis of the painful total hip replacement.

There has been significant improvement in the interpretation of diagnostic tests for the evaluation of the cemented and uncemented symptomatic total hip replacement. Lucent lines around cemented implants have often been found to represent remodeling rather than loosening. Lysis without looseness has been described as a cause of hip pain in both cemented and uncemented hip replacements. Therefore, there are a number of recent developments in diagnosis that must be considered when evaluating the symptomatic cemented or cementless total hip replacement. Some of these developments are reviewed in this paper. Other developments and contemporary algorithms for treatment incorporating these recent data will be presented in next month's issue.

Arthrography↗

PubMed1992

Clinical and radiographic analysis of the uncemented LSF total hip arthroplasty.

Forty-nine consecutive uncemented porous-coated LSF total hip prostheses were implanted in 41 patients and studied prospectively. Clinical rating as described by Harris was performed preoperatively, at 6 months and 1 year postoperatively, and annually thereafter. Anteroposterior and lateral radiographs were obtained preoperatively, immediately postoperatively, at 6 and 12 months, and annually thereafter. At the most recent follow-up visit, patients were evaluated clinically and radiographically utilizing the format recently recommended by the Hip Society. A patient satisfaction questionnaire was also completed. The follow-up period averaged 37 months (range, 24-48 months). Preoperative hip scores averaged 38 (range, 18-68) and improved to 93 at the most recent follow-up visit (range, 76-100). The incidence of mild pain was 14% at 1 year and 4% at 2 years or more. The incidence of limp was 16% slight and 8% moderate at 1 year, and 12% slight and 2% moderate at 2 years or more. Surgical fit was objectively graded as excellent in 61%, good in 33%, and poor in 6%. The authors were unable to correlate surgical fit with clinical scores or radiographic findings. According to radiographic criteria, all components were judged to be stable and 86% were judged to demonstrate objective signs of osseointegration. Patient satisfaction with the procedure was 100%. All patients stated that the procedure increased their function and decreased their pain and need for medication. Compared to a normal hip, in terms of symptoms and function, the patients rated their postoperative hip at 85% (range, 50-100%). Compared to their level of activity before their hip was symptomatic, they rated their current activity level as 83% (range, 50-100%).

Adult↗

PubMed1992

Neurologic testing with somatosensory evoked potentials in idiopathic scoliosis.

A study was undertaken to determine if a somatosensory conduction delay is present in the posterior columns of adolescents with idiopathic scoliosis. Somatosensory evoked potentials were recorded after median and posterior tibial nerve stimulation in 12 adolescent subjects being followed for idiopathic scoliosis with an average age of 14.6 years (range, 12.0-16.6 years). Twelve normal controls matched for age, sex, race, and height underwent identical testing. Evoked potential peak latencies were measured and conduction velocities calculated. Results showed no difference between scoliotics and normal controls. Comparable posterior column conduction velocities were recorded in both groups. If a defect in posterior column function does exist in adolescent idiopathic scoliosis, as previously postulated, it is not reflected by a conduction delay as measured by somatosensory evoked potential testing.

Adolescent↗

PubMed1992

Improved cementing techniques and femoral component loosening in young patients with hip arthroplasty. A 12-year radiographic review.

To assess the effect of improved methods of femoral cementing on the loosening rates in young patients, we reviewed 50 'second-generation' cemented hip arthroplasties in 44 patients aged 50 years or less. The femoral stems were all collared and rectangular in cross-section with rounded corners. The cement was delivered by a gun into a medullary canal occluded distally with a cement plug. A clinical and radiographic review was undertaken at an average of 12 years (10 to 14.8) and no patient was lost to follow-up. No femoral component was revised for aseptic loosening, and only one stem was definitely loose by radiographic criteria. By contrast, 11 patients had undergone revision for symptomatic aseptic loosening of the acetabular component and 11 more had radiographic signs of acetabular loosening.

Acetabulum↗

PubMed1992

Thigh pain despite bone ingrowth into uncemented femoral stems.

Six porous-coated, uncemented femoral components were revised at a mean of 34.5 months for persistent thigh pain. At operation the stems were rigidly stable, difficult to extract, and showed good bony ingrowth. The four men and two women, with an average age of 59 years, all had thigh pain starting within the first year, progressive over time and unresponsive to conservative measures. These cases show that rigid fixation with good bony ingrowth does not guarantee the clinical success of a porous-coated uncemented femoral stem.

Adult↗

PubMed1992

Tissue growth into porous-coated acetabular components in 42 patients. Effects of adjunct fixation.

Histologic examination was performed on 42 uncemented, porous-coated acetabular components removed for reasons not related to fixation. Included were 20 devices that had fixed pegs or spikes to aid in initial fixation and 22 devices that used screws through the component. The diagnoses and patient ages at insertion, times in situ, and reasons for removal were comparable for the two groups. Bone ingrowth was observed in 28 of the 42 acetabular components (67%). Of the 20 components with pegs or spikes, nine had no bone ingrowth, six had minimal bone ingrowth, four had moderate ingrowth, and one had extensive bone ingrowth. Of the 22 components with screws, five had no bone ingrowth, six had minimal bone ingrowth, six had moderate bone ingrowth, and five had extensive bone ingrowth. Two of the devices with screws also had external threads on the metallic shell; neither had any bone ingrowth, and the two accounted for two of the five devices having no bone ingrowth in this group. Bone ingrowth occurred more frequently, in greater amounts and was more evenly distributed anatomically in cups using screws for initial adjunct fixation. Roentgenographic and clinical findings were unreliable in predicting ingrowth of bone.

Acetabulum↗

PubMed1992

Results of conservative treatment for recalcitrant anterior knee pain in active young adults.

The purpose of this study was to determine the success rate of a standard rehabilitation protocol in the treatment of recalcitrant anterior knee pain in active young adults. All patients were active military duty personnel. Patients with a diagnosis of recalcitrant anterior knee pain were enrolled in a standard supervised program of physical therapy. Between 1986 and 1989, 139 patients met the criteria for inclusion in the study. The average age was 25.5 years, and the average time in military service was 67 months. There were 123 men and 16 women. The average duration of supervised treatment was 5.3 months. Only 34% (47 patients) were successfully returned to duty. The remainder received medical discharges. Statistically significant factors associated with successful return to full duty included older age (27.4 vs 24.5 years) and longer duration in service (98 vs 51 months). In addition, patients who returned to duty did so after an average of only 3 months of supervised rehabilitation, whereas treatment failures averaged 7.5 months of therapy.

Adult↗

PubMed1991

Tissue growth into porous primary and revision femoral stems.

The authors studied 45 uncemented porous-coated femoral stems from 45 patients: 35 primary total hip arthroplasties and 10 revisions of either cemented (7) or uncemented (3) femoral components. Histologic sections were examined quantitatively for type, amount, and distribution of tissue ingrowth; these findings were correlated with clinical and radiographic data. Fibrous tissue ingrowth predominated in both groups. Of the primary arthroplasty group, the grade of bone ingrowth in 8 specimens was none, 14 minimal, 6 moderate, and 7 more extensive. In the revision cases, the grade of bone ingrowth in 5 was none, 3 minimal, and 2 moderate. Bone ingrowth was seen more frequently in the distal porous coating, particularly in the revision cases, and most often where direct stem-endosteal canal contact had occurred. While bone ingrowth can occur in uncemented revision stems, it generally appears less abundantly than in primary total hip arthroplasty.

Adult↗

PubMed1990

Uncemented total hip arthroplasty with superior acetabular deficiency. Femoral head autograft technique and early clinical results.

A technique for primary uncemented total hip arthroplasty in the presence of a superolateral acetabular deficiency is described. The resected femoral head is used as an autograft. Matching reamers are used to ream the pseudoacetabulum and femoral head. Lag screw fixation is then performed and reaming of the graft and host bone simultaneously allows placement of an uncemented acetabular component. The hip center of rotation is returned to its anatomic center, the medial wall and subchondral bone are maintained, maximal contact and rigid fixation is obtained between femoral head autograft and host bone, and press fit of an uncemented cup is achieved. This method was applied to 10 consecutive hips in seven patients who had superior migration of the femoral head. The results were compared to those of 44 uncomplicated primary uncemented total hip arthroplasties during the same time period. While operative time and blood loss were increased in the bone graft cases, the early clinical results were equivalent to those of routine uncemented total hip arthroplasties.

Acetabulum↗

PubMed1990

Partial versus complete acute anterior cruciate ligament tears. The results of nonoperative treatment.

A study was undertaken to determine whether a significantly different clinical outcome could be expected following nonoperative treatment of acute partial anterior cruciate ligament (ACL) tears from that of complete tears. A detailed follow-up of 107 patients with arthroscopically confirmed tears was obtained; 72 were complete tears and 35 partial. The overall results in those with partial tears were 23% excellent, 29% good, 17% fair, and 31% poor; with complete tears the results were 11% excellent, 20% good, 15% fair, and 54% poor. The patients with partial tears had a lower incidence of associated meniscal tears, needed fewer reconstructions and more of them returned to sport than those with complete tears.

Adolescent↗

PubMed1990

Ankle weighting effect on gait in able-bodied adults.

Energy expenditure during ambulation was measured in 10 able-bodied subjects wearing symmetrically and asymmetrically added ankle weights. When a 1.82-kg weight was added to one ankle and then both ankles, baseline oxygen consumption per unit distance (0.148 +/- 0.025 mL O2/kg/m) increased significantly by 7.4% (0.159 +/- 0.025 mL O2/kg/m) and 17.6% (0.174 +/- 0.027 mL O2/kg/m), respectively. The rate of oxygen consumption rose by 6.3% to 11.28 +/- 1.57 mL O2/kg/min and by 14.2% to 12.12 +/- 1.75 mL O2/kg/min, respectively, but only the latter increase was significant. When gait was analyzed using the same weight-addition protocol, velocity, cadence, stride length, gait cycle, and double-limb support time showed no change. However, asymmetric weighting decreased single-limb support time, increased the swing phase, and decreased the stance phase of gait in the weighted limb. The unweighted leg was conversely affected. Symmetric ankle weighting caused a significant increase in single-limb support time for both extremities, consistent with previous data.

Adult↗

PubMed1990

Arthroscopy update #6. Arthroscopy in the osteoarthritic knee. Long-term follow-up.

A retrospective review was performed of 109 patients who underwent arthroscopic debridement of the knee for degenerative osteoarthritis. The results were evaluated using a modification of the Hospital for Special Surgery (HSS) scoring system as well as a subjective scale that measured the patients' degree of satisfaction with the procedure. Follow-up was obtained in 111 knees for an overall follow-up of 92% of knees. The mean age of the patients was 58.1 years, and the mean follow-up was 50.6 months. The overall results were 50 good, 20 fair, and 41 poor. Arthroscopic debridement offered measurable relief for 63% of the patients for a significant period of time. Although the results are equivocal by orthopaedic standards, 74% of the patients felt the procedure had been beneficial.

Adult↗