Biomedical subjects

J D Zuckerman

Publications and source records attributed to J D Zuckerman.

At least 73 records · Page 4Linked to original sources

PubMed1996

Dependency after hip fracture in geriatric patients: a study of predictive factors.

Five hundred and sixteen community-dwelling, ambulatory, geriatric hip fracture patients who were independent prior to fracture were followed prospectively to determine which patients regained their prefracture independent living status at 3-, 6-, and 12-month follow-up. At 3-, 6-, and 12-month follow-up, 78, 77, and 76% of the patients, respectively, had regained their prefracture independent living status. Analysis was performed to determine which pre- and postinjury factors were predictive of a patient regaining prefracture independent living status at 3, 6, and 12 months after fracture. Patients who were younger than age 85, independent in activities of daily living prior to fracture, independent in ambulation at hospital discharge, and who had three or more medical comorbidities were more likely to regain their prefracture independent living status.

Activities of Daily Living↗

PubMed1996

Surgical neck fractures of the proximal humerus: a laboratory evaluation of ten fixation techniques.

OBJECTIVE: A biomechanical cadaver study was performed to compare the stability and ultimate strength of ten standard fixation techniques used for the treatment of surgical neck fractures of the proximal humerus. DESIGN: One hundred twenty (60 fresh frozen, 60 embalmed) proximal humerus specimens were selected and divided into two groups: fresh frozen specimens represented a nonosteopenic group and embalmed specimens an osteopenic group. Simulated fractures were created at the level of the surgical neck, reduced, and randomly assigned to one of ten methods of fixation (six fresh frozen and six embalmed specimens per fixation group). These constructs were then mechanically tested with the humeri oriented to create primarily shear loading of the fixation. RESULTS AND CONCLUSIONS: The T-plate and screws provided significantly stronger fixation (p < 0.005) in the fresh frozen specimens than all other methods. The Ender nails/tension band construct was the second strongest fixation technique, providing significantly stronger fixation (p < 0.01) than all the remaining techniques. Four Schanz pins with one pin placed through the greater tuberosity followed by the T-plate and screws provided the strongest fixation in embalmed specimens. Tension band fixation in both humeral groups was shown to provide the least effective fixation.

Biomechanical Phenomena↗

PubMed1996

Tibiotalar contact area and pressure distribution: the effect of mortise widening and syndesmosis fixation.

An unconstrained cadaver ankle model was designed to reevaluate the effect of ankle mortise widening and syndesmotic fixation on the load-bearing characteristics of the tibiotalar joint. Tibiotalar contact area, centroid shift, and mean contact pressure were quantified using a pressure-sensitive film technique. Six fresh-frozen below-knee amputation specimens were axially loaded with 500 N in three positions: neutral, 10 degrees of dorsiflexion, and 20 degrees of plantarflexion. The tibiotalar contact area and centroid position for each specimen in its intact state were first determined and then compared with values obtained after syndesmotic fixation, mortise widening of 2 and 4 mm, and deep deltoid ligament transection. Syndesmotic fixation significantly decreased joint contact area but did not consistently affect centroid position. However, unlike earlier studies, which used more constrained ankle fracture models, mortise widening with or without deltoid rupture was not found to significantly affect contact area, centroid position, or joint contact pressure. When statically loaded, the talus moved to its position of maximal congruence in the mortise, rather than displacing laterally along with the lateral malleolus.

Ankle Joint↗

PubMed1996

The reliability of analysis of intraoperative frozen sections for identifying active infection during revision hip or knee arthroplasty.

A prospective study was performed to determine the reliability of analysis of intraoperative frozen sections for the identification of infection during 175 consecutive revision total joint arthroplasties (142 hip and thirty-three knee). The mean interval between the primary and the revision arthroplasty was 7.3 years (range, three months to twenty-three years). To reduce selections bias, tissue was obtained for frozen sections during all revisions in patients who did not have active drainage from the wound or a sinus tract. Of the 175 patients, twenty-three had at least five polymorphonuclear leukocytes per high-power field on analysis of the frozen sections and were considered to have an infection. Of these twenty-three, five had five to nine polymorphonuclear leukocytes per high-power field and eighteen had at least ten polymorphonuclear leukocytes per high-power field. The frozen sections for the remaining 152 patients were considered negative. On the basis of cultures of specimens obtained at the time of the revision operation, nineteen of the 175 patients were considered to have an infection. Of the 152 patients who had negative frozen sections, three were considered to have an infection on the basis of the results of the final cultures. Of the twenty-three patients who had positive frozen sections, sixteen were considered to have an infection on the basis of the results of the final cultures; all sixteen had frozen sections that had demonstrated at least ten polymorphonuclear leukocytes per high-power field. The sensitivity and specificity of the frozen sections were similar regardless of whether an index of five or ten polymorphonuclear leukocytes per high-power field was used. Analysis of the frozen sections had a sensitivity of 84 per cent for both indices, whereas the specificity was 96 per cent when the index was five polymorphonuclear leukocytes and 99 per cent when it was ten polymorphonuclear leukocytes. However, the positive predictive value of the frozen sections increased significantly (p < 0.05), from 70 to 89 per cent, when the index increased from five to ten polymorphonuclear leukocytes per high-power field. The negative predictive value of the frozen sections was 98 per cent for both indices. The current study suggests that it is valuable to obtain tissue for intraoperative frozen sections during revision hip and knee arthroplasty. At least ten polymorphonuclear leukocytes per high-power field was predictive of infection, while five to nine polymorphonuclear leukocytes per high-power field was not necessarily consistent with infection. Less than five polymorphonuclear leukocytes per high-power field reliably indicated the absence of infection.

Adult↗

PubMed1996

Efficacy of injections of corticosteroids for subacromial impingement syndrome.

A prospective, randomized, controlled, double-blind clinical study was performed to determine the short-term efficacy of subacromial injection of corticosteroids for the treatment of subacromial impingement syndrome. Forty patients were randomized to receive either six milliliters of 1 per cent lidocaine without epinephrine (the control group) or two milliliters containing forty milligrams of triamcinolone acetonide per milliliter with four milliliters of 1 per cent lidocaine without epinephrine (the corticosteroid group). The patients were re-examined serially until completion of the study. Nineteen patients, whose mean age was fifty-six years (range, thirty-two to eighty years), were randomized to the corticosteroid group, and twenty-one patients, whose mean age was fifty-seven years (range, thirty-two to eighty-one years), were randomized to the control group. The mean duration of symptoms before the injection was eight months for both groups. Eighteen patients in the corticosteroid group and nineteen patients in the control group had moderate or severe pain before the injection. At the most recent follow-up evaluation, at a mean of thirty-three weeks for the corticosteroid group and twenty-eight weeks for the control group, three patients in the corticosteroid group had moderate or severe pain, compared with fifteen patients in the control group. The mean active range of forward elevation and external rotation improved by 24 and 11 degrees, respectively, for the corticosteroid group and by 10 and 5 degrees, respectively, for the control group. We concluded that subacromial injection of corticosteroids is an effective short-term therapy for the treatment of symptomatic subacromial impingement syndrome. The use of such injections can substantially decrease pain and increase the range of motion of the shoulder.

Activities of Daily Living↗

PubMed1996

Medial dislocation of the long head of the biceps tendon. Magnetic resonance imaging evaluation.

Medial dislocation of the long head of the biceps branchii tendon is a rare occurrence and is often associated with degenerative or traumatic tears of the rotator cuff, specifically tears of the subscapularis tendon. Following a dislocation, the biceps tendon will assume either an intra- or extra-articular position depending on whether or not the subscapularis tendon detaches from its humoral insertion. Magnetic resonance imaging (MRI) has been found to provide valuable information concerning the location of the biceps tendon and the integrity of the rotator cuff. In this report, three patients with suspected dislocations of the biceps tendon are evaluated using MRI.

Adult↗

PubMed1996

Coracoacromial ligament function: a phylomorphic analysis.

Various morphologic parameters of the coracoacromial region were quantified for five hominoid genera to examine the evolutionary development of the coracoacromial ligament (CAL) and its significance and relationship to shoulder function. No evolutionary correlation within the family Hominoidea was found for several calculated parameters obtained from osseous dimensions and CAL length. However, from an evolutionary analysis of the order Anthropoidea, it appears that the CAL is not solely a vestigial structure in humans but rather represents a stage in the development of the hominoid shoulder with the function of providing increased mechanical stability to the superior bony vault.

Animals↗

PubMed1996

Fixation stability of olecranon osteotomies.

Eighteen pairs of fresh frozen human upper extremities were selected and each randomized to 2 of 3 olecranon osteotomy and fixation technique groups: (1) transverse osteotomy with 0.062 Kirschner wire and tension band fixation; (2) chevron osteotomy with 6.5-mm cancellous lag screw and tension band fixation; and (3) oblique intraarticular osteotomy with 3.5-mm cortical lag screw and tension band fixation. The arms were mounted with the elbow at 90 degrees flexion and the wrist constrained; a dual linear displacement transducer across the osteotomy was used to determine angulation, translational displacement, and the total gap size. First the brachialis and then the triceps were incrementally loaded to 10 kg using a pulley and cable system to control force direction; the muscle load versus osteotomy displacement was recorded. Cycling with 10 kg was repeated 20 times with the brachialis and triceps alternately loaded and the osteotomy displacement remeasured. There were no statistically significant differences between the amounts of displacement for the 3 osteotomy and fixation techniques caused by either muscle action. The total displacement caused by the brachialis load for all techniques was appreciably greater than that of the triceps load. No significant increase in displacements occurred after 20 load cycles. These results suggest all 3 olecranon osteotomy and fixation techniques offer comparable stability, so the choice of technique should be left to the surgeon's preference.

Biomechanical Phenomena↗

PubMed1995

Effects of supine positioning and fracture post placement on the perineal countertraction force in awake volunteers.

An instrumented traction post was used to determine the magnitude and direction of the countertraction force applied to the perineum of 15 awake volunteers for a series of 12 positions used in fracture surgery and compared with their corresponding neutral position controls. The results demonstrated that adduction of the affected limb and abduction of the contralateral limb applied the greatest force to the perineum with ipsilateral and contralateral placement of the fracture post. These two maneuvers increased the perineal countertraction force 80% above their respective neutral readings. Abduction of the affected limb reduced the traction force by 50% with ipsilateral and contralateral placement of the fracture post. Flexion-abduction-external rotation of the contralateral leg reduced the forces applied to the perineum by 60% when the fracture post was placed contralateral to the affected limb. Contralateral placement of the post decreased the perineal countertraction force 46% below the value for ipsilateral post placement for this maneuver. Internal and external rotation of the affected limb had no effect on the perineal countertraction force for either placement of the post. There was a significant decrease in the perineal forces for the neutral positions after adduction of the affected limb and abduction of the contralateral limb with ipsilateral placement of the post, indicating that the volunteers shifted on the fracture table in response to pain. There was no significant difference in the direction of the countertraction force for the various positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Modular unipolar versus bipolar prosthesis: a prospective evaluation of functional outcome after femoral neck fracture.

Between January 1, 1987, and December 31, 1992, 140 community-dwelling geriatric patients > or = 65 years of age with a displaced femoral neck fracture (Garden III-IV) underwent primary prosthetic replacement and were followed prospectively for a minimum of 1 year. Overall, 92 patients received a cemented bipolar prosthesis and 48 patients received a cemented modular unipolar prosthesis. There were no statistically significant differences between the two groups with respect to preinjury characteristics (age, sex, and number and severity of medical comorbidities) and functional ability. There were no statistically significant differences between the two groups with regard to the number of postoperative complications, length of stay, and 1 year mortality rate. An in-depth functional evaluation was obtained as follows: level of ambulation, independence in basic activities of daily living (feeding, bathing, dressing, toileting), and independence in instrumental activities of daily living (food shopping, food preparation, banking, laundry, housework, and use of public transportation). At 1 year follow-up, no statistically significant differences in functional ability were identified between the unipolar and bipolar groups. Furthermore, at a minimum of 1 year follow-up, there were no statistically significant differences between the two groups with regard to the need for revision surgery or the incidence hip pain. Based on the results of this study, there does not appear to be any advantage to the use of bipolar endoprosthesis for the treatment of femoral neck fractures in the elderly patient. The lower cost of modular unipolar prostheses compared with bipolar prostheses provides additional support for their use.

Aged↗

PubMed1995

Postoperative complications and mortality associated with operative delay in older patients who have a fracture of the hip.

We prospectively studied 367 patients who had a fracture of the hip, to determine the effect of an operative delay on postoperative complications and on the one-year mortality rate. All of the patients were at least sixty-five years old, cognitively intact, living at home, and able to walk before the fracture. An operative delay was defined as an interval of three calendar days or more between the time of admission to the hospital and the operation. The operation was performed within two calendar days after admission in 267 (73 per cent) of the patients. When the factors of the patient's age and sex and the number of pre-existing medical conditions were controlled, it was found that an operative delay beyond this period approximately doubled the risk of the patient dying before the end of the first postoperative year. When the patient's age and sex and the severity of pre-existing medical conditions were controlled, there was also an increase in mortality associated with an operative delay, although this was not significant. With the numbers studied, an operative delay beyond two calendar days did not have a significant effect on the prevalence of complications during hospitalization. We concluded that an operative delay of more than two calendar days after admission is an important predictor of mortality within one year for elderly patients who have a fracture of the hip and who are cognitively intact, able to walk, and living at home before the fracture. Optimally, such patients should have the operation within two calendar days after admission to the hospital.

Activities of Daily Living↗

PubMed1995

The role of intraoperative frozen sections in revision total joint arthroplasty.

We performed a retrospective analysis of thirty-three consecutive total hip and knee (twenty-three hip and ten knee) revision arthroplasties during which intraoperative frozen sections were analyzed. Data for the study were collected by means of a review of the charts, radiographic analysis, and evaluation of both frozen and permanent histological sections. The frozen sections, of periprosthetic tissue at the bone-cement interface or the pseudocapsule, were considered positive for active infection if there were more than five polymorphonuclear leukocytes per high-power field in at least five distinct microscopic fields. All patients were available for follow-up, at an average of thirty-six months (range, seventeen to seventy-nine months) after the initial revision operation. The frozen sections from ten patients were positive for infection, and those from twenty-three patients were negative. Comparison of the results of the analyses of the frozen sections (both positive and negative) with those of the analyses of the permanent histological sections of similar tissue showed a correlation of 100 per cent (sensitivity, 1.00; specificity, 1.00; and accuracy, 1.00). Nine patients had positive intraoperative cultures, and all of them had positive frozen sections (sensitivity, 1.00). Of the twenty-four patients who had negative intraoperative cultures, twenty-three had negative frozen sections (specificity, 0.96). Of the nine patients who had positive intraoperative cultures, only two were found to have infection on intraoperative gram-staining. The surgeon's operative assessment regarding the presence of infection, compared with the final pathological diagnosis, demonstrated a sensitivity of 0.70, a specificity of 0.87, and an accuracy of 0.82. All ten patients who had positive frozen sections were managed with excision arthroplasty; six of them subsequently had reimplantation, and the excision was the definitive procedure in the remaining four. One patient who had had a delayed reimplantation had a secondary skin slough and eventually was managed with an arthrodesis of the knee. In the group that had negative frozen sections, eighteen patients had a primary exchange revision arthroplasty and five had a delayed reimplantation. At the time of follow-up, one patient who had had a delayed reimplantation had radiographic loosening of the femoral component and was asymptomatic. One patient who had had a primary exchange arthroplasty was managed with a second revision because of aseptic loosening. There was no clinical recurrence of infection in any patient. The data indicate that analysis of frozen sections of periprosthetic tissue is a reliable predictor of the presence of active infection during revision joint arthroplasty. We recommend its use to differentiate aseptic from septic loosening.

Adult↗

PubMed1995

Humeral head replacement for glenohumeral arthritis.

From July 1977 through March of 1983, humeral head replacement was performed on 35 shoulders with osteoarthritis and 32 shoulders with rheumatoid arthritis and followed-up for an average of 9.3 years. Satisfactory pain relief was achieved in 44 (66%) and 52 of the shoulders (78%) were described by patients as being much better or better. Active elevation was improved from an average of 84 degrees to an average of 110 degrees with external rotation improving from 20 degrees to 44 degrees. Strength improvement also occurred. Only three complications developed, and these did not affect the final outcome. Because of moderate or severe pain, 12 shoulders (18%) required revision to total shoulder arthroplasty, and all patients were relieved of their pain. The result ratings were excellent in 10 shoulders, satisfactory in 23, and unsatisfactory in 34 (51%). With longer follow-up, a satisfactory level of pain relief may not continue for those patients with osteoarthritis and rheumatoid arthritis who have had humeral head replacement alone. Whereas this form of treatment should certainly be considered in those patients who have inadequate glenoid bone to support a glenoid implant and probably be considered in younger patients or patients who wish to remain more active, these latter patients must be fully appraised that the probability of continuing pain relief is less than has often been appreciated.

Adult↗

PubMed1995

Ambulatory ability after hip fracture. A prospective study in geriatric patients.

Three hundred thirty-six community-dwelling, previously ambulatory, geriatric patients with hip fracture were observed prospectively to determine ambulatory ability at a minimum followup of 1 year. One hundred thirty-seven (41%) patients maintained their prefracture ambulatory ability at a minimum followup of 1 year; 134 (40%) patients remained ambulatory but became more dependent on assistive devices; 39 (12%) previous community ambulators became household ambulators, and 26 (8%) patients became nonfunctional ambulators. Analysis was performed to determine which pre- and postinjury factors were predictive of failure to recover ambulatory capacity 1 year after fracture. Potential predictor variables analyzed included age, gender, number of comorbid conditions, prefracture ambulatory ability, prefracture living situation, fracture type, American Society of Anesthesiologists rating of operative risk, type of surgery, and number of postoperative complications. Multiple logistic regression analysis identified significant contributions of age, prefracture ambulatory ability, American Society of Anesthesiologists rating of operative risk, and fracture type to ambulatory recovery.

Activities of Daily Living↗

PubMed1995

Biomechanical comparison of the sliding hip screw and the dome plunger. Effects of material and fixation design.

We studied the biomechanical behaviour of three sliding fixation devices for trochanteric femoral fractures. These were a titanium alloy sideplate and lag screw, a titanium alloy sideplate and dome plunger with cement augmentation, and a stainless-steel sideplate and lag screw. We used 18 mildly osteoporotic cadaver femora, randomly assigned to one of the three fixation groups. Four displacement and two strain gauges were fixed to each specimen, and each femur was first tested intact (control), then as a two-part fracture and then as a four-part intertrochanteric fracture. A range of physiological loads was applied to determine load-bearing, load-sharing and head displacement. The four-part-fracture specimens were subsequently tested to failure to determine maximum fixation strengths and modes of failure. The dome-plunger group failed at a load 50% higher than that of the stainless-steel lag-screw group (p < 0.05) and at a load 20% higher than that of the titanium-alloy lag-screw group (NS). All 12 lag-screw specimens failed by cut-out through the femoral head or neck, but none of the dome-plunger group showed movement within the femoral head when tested to failure. Strain-gauge analysis showed that the dome plunger produced considerably less strain in the inferior neck and calcar region than either of the lag screws. Inferior displacement of the femoral head was greatest for the dome-plunger group, and was due to sliding of the plunger. The dome plunger with cement augmentation was able to support higher loads and did not fail by cut-out through the femoral head.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗

PubMed1995

Fractures of the proximal part of the femur.

The orthopaedic surgeon has a multitude of internal fixation devices and techniques available for use in the treatment of subtrochanteric fractures of the proximal femur. The successful use of second-generation locking nails is technically demanding. Close attention to positioning of the patient, reduction of the fracture, placement of the guide-wire, and insertion of the nail and of the proximal and distal locking screws is mandatory. The newer, high-strength hip-screws allow good fixation of a fracture that extends into the piriformis fossa. If medial comminution is present, this technique is best performed in conjunction with indirect reduction and bone-grafting. With proper technique, these devices allow the surgeon to manage predictably a complex subtrochanteric fracture that previously had to be treated with traction or extensive dissection and with (frequently inadequate) internal fixation.

Adult↗

PubMed1995

The incidence of full thickness rotator cuff tears in a large cadaveric population.

The incidence of full thickness rotator cuff tears was determined after careful dissection and inspection of 235 male and female cadavers ranging in age from 27-102 years with an average age of 64.7 years. A total of 456 shoulders were examined. Partial thickness tears were excluded from the study. Seventy-eight shoulders, 17% (53 female, 26 male) were found to have full thickness tears. The average age of those cadavers with tears was 77.8 years as compared to 64.7 years in the intact group. The incidence of full thickness tears was also found to increase with increasing age. In cadavers under 60 years of age the incidence of rotator cuff tears was 6% as opposed to 30% in those over 60 years of age.

Adult↗

PubMed1994

Vertical shear fractures of the medial malleolus: a biomechanical study of five internal fixation techniques.

Fifty embalmed human tibias were osteotomized to create a simulated vertical shear (supination-adduction) fracture of the medial malleolus and were stabilized using one of five internal fixation techniques. In offset axial testing, which simulated supination-adduction loading, the fixation strength of tibias stabilized with either cortical or cancellous lag screws placed perpendicular to the osteotomy was over five times greater than the strength of those treated with an antiglide plate and nearly two and a half times greater than those treated with cancellous lag screws placed oblique to the osteotomy. The tibias stabilized with cancellous lag screws placed perpendicular to the osteotomy exhibited twice the fixation strength of the tibias stabilized with an antiglide plate and distal lag screw. The tibias stabilized with an antiglide plate and distal lag screw and perpendicularly placed cortical or cancellous lag screws demonstrated three times greater resistance to displacement to the applied supination-adduction load than those stabilized with an antiglide plate alone. In offset transverse testing, to simulate loading in external rotation, the mean failure load of the tibias stabilized with cancellous lag screws placed perpendicular to the osteotomy was over two and a half times greater than those stabilized with an antiglide plate and distal lag screw. No significant differences were observed in the resistance to displacement for these tests. These results support the use of lag screws placed perpendicular to the fracture surface for stabilization of vertical shear fractures of the medial malleolus and indicate that the use of an antiglide plate, with or without a distal lag screw, does not offer any advantage over lag screw fixation.

Biomechanical Phenomena↗