Faculty Bibliography

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

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

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

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

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)

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)

Twenty-six hemiarthroplasties were performed for acute three- and four-part proximal humerus fractures between March 1986 and December 1991. Postoperative pain, active range of motion, and function were evaluated in 22 patients at a mean follow-up period of 30 months (range 12 to 66 months) with the American Shoulder and Elbow Surgeons evaluation form. Seventy-three percent of patients reported only slight or no pain. Active forward elevation averaged 107 degrees, external rotation averaged 31 degrees, and the average internal rotation was to the second lumbar vertebra. Strength and stability were rarely problematic. Seventy-three percent of patients reported difficulty with at least three of 15 functional tasks tested. Lifting, carrying a weight, and using the hand at or above shoulder level were the most common limitations. This study indicates that hemiarthroplasty for acute three- and four-part fractures generally can be expected to result in painfree shoulders. However, recovery of function and range of motion are much less predictable

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

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