The role of preoperative aspartate aminotransferase-to-platelet ratio index in predicting complications following total hip arthroplasty.

BACKGROUND: The purpose of this study was to investigate the relationship between preoperative aspartate aminotransferase-to-platelet ratio index (APRI) and postoperative complications following total hip arthroplasty (THA). METHODS: All THA for osteoarthritis patients from 2007 to 2020 within the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database were included in this study. Subjects were subsequently divided into cohorts based on APRI. Four groups, including normal range, some liver damage, significant fibrosis, and cirrhosis groups, were created. Comparisons between groups were made for demographics, past medical history, and rate of major and minor complications. Other outcomes included readmission, reoperation, discharge destination, mortality, periprosthetic fracture, and postoperative hip dislocation. Multivariate logistic regression analysis was performed to determine the role of preoperative APRI in predicting adverse outcomes. Statistical significance was set at p < 0.05. RESULTS: In total, 104,633 primary THA patients were included in this study. Of these, 103,678 (99.1%) were in the normal APRI group, 444 (0.4%) had some liver damage, 256 (0.2%) had significant fibrosis, and 253 (0.2%) had cirrhosis. When controlling for demographics and relevant past medical history, the abnormal APRI groups had a significantly higher likelihood of major complication, minor complication, intraoperative or postoperative bleeding requiring transfusion, readmission, and non-home discharge (all p < 0.05) compared to normal APRI individuals. CONCLUSIONS: Abnormal preoperative APRI is linked with an increasing number of adverse outcomes following THA for osteoarthritis for patients across the United States. LEVEL OF EVIDENCE: Level I.

Effects of simulated scapular protraction on anterior glenohumeral stability.

We evaluated the effect of simulated scapular protraction on anterior glenohumeral translation and in situ inferior glenohumeral ligament strain. Five fresh-frozen cadaveric glenohumeral joints were tested in the position of apprehension while simulating scapular protraction using a custom translation testing device and a differential variable reluctance transducer. The results showed a statistically significant decrease in anterior glenohumeral translation as the scapula was increasingly rotated to simulate 20 degrees of scapular protraction. With 15 N of thorax-based, anteriorly directed load, the mean anterior translation was 6.3 +/- 1.6 mm (mean +/- SEM). With 10 degrees of simulated scapular protraction, translation decreased to 4.1 +/- 1.0 mm; with 20 degrees of simulated scapular protraction, it decreased further to 2.5 +/- 0.5 mm. For each of the other anteriorly directed loads, translations also decreased when 20 degrees of scapular protraction was simulated. Concurrently for each of the anteriorly directed loads, there was increased in situ strain of the anterior band of the inferior glenohumeral ligament with increased simulated scapular protraction. These results suggest that repetitive or chronic protraction of the scapula may result in excessive strain and, ultimately, insufficiency in the anterior band of the inferior glenohumeral ligament.

Shoulder injuries in competitive swimmers.

Sports medicine literature often refers to "swimmer's shoulder." Increasingly, however, it is evident that swimmer's shoulder is a spectrum of maladies whose underlying origins may be incidental to athletic activity. Those dealing with the treatment of swimmers should have a thorough understanding of the differential diagnosis of the shoulder, the age range of competitive swimmers, and the effects of the aging process, and age-related disease processes and should consider the possibilities of neoplasm, degenerative diseases, and acquired processes such as arthritis or metabolic diseases.

A correlation between shoulder laxity and interfering pain in competitive swimmers.

Shoulder pain in the swimming athlete that interferes with effective training is serious and may result in decreased performance. Based on the hypothesis that shoulder laxity is an important factor in shoulder pain, this study of 40 senior national and elite swimmers was undertaken. A questionnaire identified those athletes currently suffering from such pain. Shoulder laxity was assessed using standard clinical tests, from which a laxity score was derived. A statistically significant correlation was identified between the shoulder laxity score and the presence of interfering shoulder pain, confirming the hypothesis of the study. These results have direct implications for training the symptomatic athlete.

Swimming injuries. An overview.

Most injuries and complaints encountered in swimming athletes are repetitive microtrauma or overuse, and successful management does not usually require surgical intervention. Rest and other measures to reduce inflammation are often required. Many injuries originate from faulty techniques or mechanisms, and an assessment must be made of the swimming biomechanics of any injured athlete to identify faults that may contribute to injury. It is also important to look at the total training programme of the athlete to identify other factors, such as weight training or dry land programmes, that may be contributing to injury. It is important to understand that, while rest or reduced training may be necessary, every effort to keep the swimmer "in the water' should be made, as cessation of training may lead to a rapid detraining effect.

Technique for intraoperative construction of PMMA spacer in total knee revision.

A technique to custom design an manufacture an appropriate spacer for use in the salvage procedure for an infected total knee replacement uses cheap, readily available materials and is simple to construct. The use of the spacer has been a valuable adjunct to the salvage procedure and has enhanced patient care and comfort in the prosthesis-free interval.

A survey of interfering shoulder pain in United States competitive swimmers.

The prevalence of shoulder pain in United States competitive swimmers has not been extensively surveyed but is perceived as common. To evaluate this concern, a questionnaire survey was conducted on 1262 United States swimmers: 993 age group, 198 senior development, and 71 national team athletes. We sought to identify the incidence of interfering shoulder pain in this population and how it is influenced by various training tasks. The prevalence of current shoulder pain in these groups varied between 10% (age group) to 26% (national team) and increased with time in the sport. In those athletes with a painful shoulder, weight training, use of hand paddles, kickboard use, stretching, and various resistance activities aggravated the painful shoulder. This survey has identified that interfering shoulder pain is present in a substantial number of competitive swimmers.

Shoulder torque changes in the swimming athlete.

Torque production was assessed in the shoulders of competitive men and women swimmers for the motions of abduction, adduction, and external and internal rotation. Testing was performed on the Cybex II dynamometer and the results were compared to controls. In addition, the ratios of torque development for adduction:abduction and external rotation:internal rotation were evaluated. The results demonstrated a statistically significant increase in torque production in swimmers for most motions tested. Statistically significant ratio shifts were also noted. The ratio of adduction:abduction increased and that for external rotation:internal rotation decreased. We think these shifts in the torque ratios in swimmers' shoulders resulted from sport-specific repetitive activity that emphasizes adduction and internal rotation.

Isokinetic torque imbalances in the rotator cuff of the elite water polo player.

The specific repetitive activity of water polo, like baseball pitching, emphasizes adduction and internal rotation. This study used the Cybex II to evaluate the isokinetic strength of the rotator cuff in elite water polo players and in a group of control subjects. The water polo players were significantly stronger than the controls. Of greater importance was the confirmation of imbalances in the rotator cuff force couples of adduction/abduction and external/internal rotation. These changes are similar to those reported for pitchers. The adductors in the water polo group had gained in relative strength resulting in an increase in the adduction/abduction ratio to about 2:1. The internal rotators had gained in relative strength resulting in a decrease in the external/internal ratio to about 0.6:1. For both force couples the differences are more apparent at a slow speed. Side-to-side differences were not significant.

Comparison of bipolar implants with fixed-neck prostheses in femoral-neck fractures.

A retrospective study of 76 Bateman universal proximal femoral endoprostheses with a mean follow-up period of 32 months was compared to a group of 36 Thompson endoprostheses and 16 Moore endoprostheses, with a mean follow-up period of 35 months and 31 months, respectively. Harris hip scores, when corrected for preoperatively impaired function, yielded a mean score of 85 for the Bateman group, compared to a mean of 77 for both the Thompson and Moore groups. Fifteen patients received the Bateman device for reconstructive purposes and had a mean Harris hip score of 90. Morbidity was comparable between the Bateman and Thompson groups. The deep-infection rate was 3.9%, and the 32-day perioperative mortality was 4.6%, rising to 29% at the time of review. Preselection factors placed younger, more functional patients in the Bateman group (mean age, 65 years; mortality, 11%), compared to the Thompson group (mean age, 72 years; mortality, 39%) and the Moore group (mean age, 73 years; mortality, 41%). Continued evaluation of the Bateman endoprosthesis is required to better define its potential to lessen the long-term problems of pain, loosening, and acetabular wear.

Enhancement of blood lactate clearance following maximal swimming. Effect of velocity of recovery swimming.

Swimming is an endurance-intensive sport resulting in accumulation of lactate. Repeat performances are often necessary in championship events. Lactate produced during a maximal effort requires time to metabolize to a base level. If this does not occur, performance in a repeat effort may be impaired. Thus, techniques to enhance lactate clearance are of potential benefit to the athlete. We have demonstrated previously that swimming at 65% of maximum velocity significantly improved lactate clearance over passive resting. This study tested the effect of various swimming velocities on lactate clearance. Following a maximal swim, blood lactate clearance was tracked during a 15 minute cool down swim. Velocities of 55%, 65%, and 75% of maximum were tested. The results confirmed that cool down swimming will return lactate values to near resting levels in the test interval. However, statistical superiority of any of the test velocities was not demonstrated. The intensity of the swim should be below the lactate accumulation level. The 65% of maximum velocity was felt by all swimmers to be most comfortable and is a good target velocity for the athlete to reference.

Anterior glenoid labrum damage: a painful lesion in swimmers.

The diagnosis of swimmer's shoulder has long connoted a malady usually perceived to be impingement syndrome. However, as greater understanding of shoulder mechanics and diagnosis has been applied to the shoulder of swimmers, it is apparent that they too suffer from a variety of problems common to all overhead sports. This paper describes the functional instability problem of labral damage in the swimmer. Isolated labrum damage is part of a spectrum of anterior shoulder problems. This lesion is particularly disturbing to the swimmer, and its successful management through arthroscopic means is a boon. Correct diagnosis is paramount if a treatment is to be successful. The lesion in swimmers is described as well as its diagnosis by examination and computerized tomography (CT) arthrography.

Mechanical properties and early clinical experience with xenograft biomaterials.

Evaluation of new materials for ligament and tendon reconstruction has opened up a new area of orthopaedic research. This report outlines the mechanical properties, animal evaluations, and early clinical results from tests of a xenograft biomaterial of bovine source treated with a gluteraldehyde-based process. A clinical trial under FDA guidelines is currently underway.

Painful Shoulder in Swimmers: A Diagnostic Challenge.

In brief: Painful shoulder can cause significant disability in swimmers, and in elite swimmers it may even force premature retirement. Treatment of this problem has been difficult, and surgery has been perceived as generally unsuccessful. The author asserts that "swimmer's shoulder" is not an anatomically based diagnosis and that the frequent lack of a specific diagnosis probably has hindered treatment. New investigative tools, such as arthrography and NMR imaging, have improved the chances of reaching an accurate diagnosis. The author lists the many regional problems that can cause shoulder pain, describes physical, clinical, and laboratory tests for use in diagnosis, and outlines approaches to management of the problem.

A histologic assessment of canine anterior cruciate substitution with bovine xenograft.

Glutaraldehyde cross-linked bovine xenograft anterior cruciate ligament replacement has been investigated in dogs. The implants were functional for the activities of the dogs at one year of follow-up study. The knees were stable, and the articular surfaces on gross inspection showed only minimal evidence of degenerative changes. Histologic evaluation of the implants demonstrated a progressive ingrowth of the xenograft by host tissues. The host tissues grew parallel to the collagen scaffolding of the graft and consisted of host blood vessels and fibroblastic elements that produced collagen of host origin. The host response was benign in appearance without cellular evidence of rejection phenomena.

Bovine xenograft collateral ligament replacement in the dog.

A study of the use of glutaraldehyde-stabilized bovine xenograft material as a collateral ligament replacement in 16 dogs has been done. Six xenograft implant complexes harvested 4 months postoperatively failed in tension at 772.2 +/- 463.5 versus 799.7 +/- 162.7 N (+/- 1 SD) for controls (p greater than 0.05, paired t test). Histologic evaluation in 10 dogs after implants of up to 1 year duration demonstrated a progressive invasion of the xenograft by host tissues. Xenograft remnants were easily identifiable at 1 year. The host tissues invaded in parallel to the passive collagen scaffolding of the xenograft and consisted of vessels and fibroblastic elements that produced collagen of host origin.

Contractile properties of slow and fast muscle following tourniquet ischemia.

Tourniquet application is commonly used during surgery on an extremity to create a bloodless field. Investigations have focused on the ultrastructural, histochemical, and biochemical effects of tourniquet ischemia on muscle. Few studies, however, have examined the influence of tourniquet ischemia on the contractile properties of muscle. The purpose of this study was not only to examine this latter consideration, but also to determine whether slow and fast muscles exhibit a differential response. In adult male guinea pigs, the plantaris and soleus muscles of control (N = 5) and experimental legs (N = 5) were tested for time-peak-tension (TPT), one-half relaxation time (1/2RT), maximal twitch tension (Pt), and maximal tetanic tension (Po). The experimental leg was subjected to a 2 hour tourniquet which was placed around the thigh. Muscles of this leg were tested following a 2 hour recovery period. In three of the five animals, no response could be elicited from either the plantaris or soleus muscles of the experimental leg. In those instances where the experimental muscles were capable of generating force, the plantaris was clearly more effected. While tension production in the soleus was reduced by approximately 55%, the plantaris exhibited approximately a 90% decrease in tension output. Furthermore, both TPT and 1/2RT demonstrated consistent changes. These results indicate that the contractile properties of both the soleus and plantaris are dramatically effected by a 2 hour tourniquet. They further suggest that there may be a differential response based upon fiber type.

Compression arthrodesis of the ankle following failed ankle arthroplasty using hoffmann® external fixation.

Nine patients with failed Irvine Total Ankle Arthroplasties have been treated by compression arthrodesis with Hoffmann external fixators. Six were men and three were women; ages ranged from 33 to 70 years. An anterior approach was used with application of a Hoffmann external fixator. Three pins were placed in the distal tibia, and three pins in the talus. After six to eight weeks, the fixator was removed. The patients were placed in a short leg walking cast until fusion was complete. All nine ankles fused primarily, in an average of 16.9 weeks (range: ten to 23 weeks). There were two complications of delayed wound closures. There were no problems with pin tract infections or osteomyelitis.