THE MODIFIED STAR EXCURSION BALANCE AND Y-BALANCE TEST RESULTS DIFFER WHEN ASSESSING PHYSICALLY ACTIVE HEALTHY ADOLESCENT FEMALES.

BACKGROUND: The modified Star Excursion Balance Test (mSEBT) and Y-Balance Test (YBT) are two common methods for clinical assessment of dynamic balance. Clinicians often use only one of these test methods and one outcome factor when screening for lower extremity injury risk. Dynamic balance scores are known to vary by age, sex and sport. The physically active adolescent female is at high risk for sustaining lower extremity injuries, specifically to the anterior cruciate ligament (ACL). Thus clarity regarding the use of dynamic balance testing results in adolescent females is important. To date, no studies have directly compared the various outcome factors between these two dynamic balance tests for this population. PURPOSE: To determine if there was an association between the mSEBT and YBT scores for measured reach distances, calculated composite score and side-to-side limb asymmetry in the ANT direction in physically active healthy adolescent females. STUDY DESIGN: Cross-sectional study. METHODS: Twenty-five healthy, physically active female adolescents (mean age, 14.0 ± 1.3 years) participated. Reach distances, a composite score and side-to-side limb asymmetry for the mSEBT and YBT, for each limb, were compared and examined for correlation. RESULTS: There were significant differences and moderate to excellent relationships between the measured reach directions between the mSEBT and the YBT. Injury risk classification, based on limb asymmetry in the anterior reach direction, differed between the tests. However, the calculated composite scores from the two tests did not differ. CONCLUSIONS: Performance scores on a particular reach direction should not be used interchangeably between the mSEBT and YBT in physically active adolescent females, and should not be compared to previously reported values for other populations. LEVEL OF EVIDENCE: Level 3.

The budding yeast Msh4 protein functions in chromosome synapsis and the regulation of crossover distribution.

The budding yeast MSH4 gene encodes a MutS homolog produced specifically in meiotic cells. Msh4 is not required for meiotic mismatch repair or gene conversion, but it is required for wild-type levels of crossing over. Here, we show that a msh4 null mutation substantially decreases crossover interference. With respect to the defect in interference and the level of crossing over, msh4 is similar to the zip1 mutant, which lacks a structural component of the synaptonemal complex (SC). Furthermore, epistasis tests indicate that msh4 and zip1 affect the same subset of meiotic crossovers. In the msh4 mutant, SC formation is delayed compared to wild type, and full synapsis is achieved in only about half of all nuclei. The simultaneous defects in synapsis and interference observed in msh4 (and also zip1 and ndj1/tam1) suggest a role for the SC in mediating interference. The Msh4 protein localizes to discrete foci on meiotic chromosomes and colocalizes with Zip2, a protein involved in the initiation of chromosome synapsis. Both Zip2 and Zip1 are required for the normal localization of Msh4 to chromosomes, raising the possibility that the zip1 and zip2 defects in crossing over are indirect, resulting from the failure to localize Msh4 properly.

An analysis of the diagnostic accuracy of the Hawkins and Neer subacromial impingement signs.

The purpose of this study was to assess the diagnostic accuracy of the Neer and Hawkins impingement signs for the diagnosis of subacromial bursitis or rotator cuff pathosis. Eighty-five consecutive patients undergoing shoulder arthroscopy by a single surgeon were documented prospectively for the positive and negative clinical and arthroscopic pathologic findings. The Neer sign was found to have a sensitivity of 75% for the appearance suggestive of subacromial bursitis; this compared with 92% for the Hawkins sign. For rotator cuff tearing, the sensitivity of the Neer sign was 85% and the sensitivity of the Hawkins sign was 88%. Specificity and positive predictive values for the two tests were low, being not much higher than pretest probability. The two tests had a high negative predictive value (96% for bursitis, 90% for rotator cuff tearing) when they were combined. The results are compared with those reported in the literature. We conclude that the Neer and Hawkins signs are sensitive for appearances suggestive of subacromial bursitis and rotator cuff partial or complete tearing with a high negative predictive value. However, they lack specificity in comparison with arthroscopic findings.

Knee strength deficits after hamstring tendon and patellar tendon anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to examine the strength of the knee flexors and knee extensors after two surgical techniques of ACL reconstruction and compare them to an age and activity level matched control group. METHODS: Twenty-four subjects who had undergone ACL reconstruction greater than 1 yr previously were placed into one of two groups according to autograft donor site: patellar tendon (BPB; N = 8) and hamstring (H; N = 16), and compared with an active, control group (N = 30). Knee flexor and extensor strength was evaluated using isovelocity dynamometry (5 speeds, eccentric and concentric, 5-95 degrees ROM). Strength maps were used to graphically analyze strength over a broad operational domain of the neuromuscular system. Average strength maps were determined for each autograft group and compared with controls. A difference map (control minus graft group) and confidence (t-test) maps were used to quantitatively identify strength deficits. RESULTS: The combined ACL group (N = 24) revealed a global 25.5% extensor strength deficit, with eccentric regional (angle and velocity matched) deficits up to 50% of control. Strength deficits covered over 86% of the sampled strength map area (P < 0.01). These knee extensor strength deficits are greater than previously reported. In addition, the BPB group demonstrated a concentric, low velocity, knee extensor strength deficit at 60-95 degrees that was not observed in the H group. Significant graft site dependent, regional knee flexor deficits of up to 50% of control were observed for the H group. CONCLUSIONS: Strength deficits localized to specific contraction types and ranges of motion were demonstrated between the ACL and control groups that were dependent upon autograft donor site. Postoperative rehabilitation protocols specific to these deficits should be devised.

The efficacy of magnetic resonance imaging in acute knee injuries.

OBJECTIVE: To evaluate the clinical efficacy of magnetic resonance imaging (MRI) of the knee in acute injuries with indeterminate clinical findings, using arthroscopy as a gold standard. DESIGN: A prospective double-blind study was performed. All patients underwent MRI on a 1.5 T magnet using dual spin echo pulse sequences. This was followed by arthroscopy. SETTING: Tertiary care referral center. PATIENTS: Twenty-three patients with an average age of 26 years satisfied the study criteria. Patients had to have been seen by one of two orthopaedic surgeons within 6 weeks of sudden trauma to the knee complicated by a hemarthrosis, clinical assessment of which was equivocal. RESULTS: The respective sensitivity and specificity for MRI of the knee were 90% (18/20) and 67% (2/3) for detecting any anterior cruciate ligament injury, 50% (1/2) and 86% (18/21) for detecting medial meniscal tears, and 88% (7/8) and 73% (11/15) for detecting lateral meniscal tears. MRI also identified injuries that could not be assessed on arthroscopy, including 14 bone bruises, five posterior cruciate ligament tears, nine medial collateral ligament tears, and one lateral collateral ligament tear. The detection of composite injury requiring surgical intervention yielded a sensitivity of 100% (16/16) and a specificity of 71% (5/7). Prospective use of MRI evaluation of the knee could have prevented 22% (5/23) of diagnostic arthroscopic procedures. CONCLUSION: Equivocal clinical findings in patients with acute knee injury should lead to use of MRI in an appropriate clinical setting. To our knowledge a prospective study of the efficacy of MRI of the knee in this patient population has not been reported. In the presence of such inclusion criteria, the results of our study support the use of early MRI to guide further surgical management.

Congenital anomaly of the biceps tendon and anatomy within the shoulder joint.

This is a case report of a congenital anomaly of the biceps tendon whereby the biceps tendon is adherent to the undersurface of the rotator cuff throughout its course in the shoulder joint.

Malaria parasites contain two identical copies of an elongation factor 1 alpha gene.

Elongation factor 1alpha (EF-1alpha) is an abundant protein in eukaryotic cells, involved chiefly in translation of mRNA on the ribosomes, and is frequently encoded by more than one gene. Here we show the presence of two identical copies of the EF-1alpha gene in the genome of three malaria parasites, Plasmodium knowlesi, P. berghei and P. falciparum. They are organized in a head-to-head orientation and both genes are expressed in a stage specific manner at a high level, indicating that the small intergenic region contains either two strong promoters or a single bidirectional one. Both genes are expressed at the same time during erythrocytic development of the parasite. This expression pattern and the 100% similarity of the two genes excludes the possibility that the duplicated genes developed in accordance to the different types of ribosomes in Plasmodium. It is more likely that the duplication reflects a gene dosage effect. Comparison of codon usage in the Cdc2-related kinase genes (CRK2) of Plasmodium, which are expressed at a very low level, with the EF-1alpha genes indicates the existence of a codon bias for highly expressed genes, as has been shown in other organisms.

Combined tear of the posterior cruciate and medial collateral ligaments resulting in a locked knee.

A case is presented of a combined tear of the posterior cruciate and medial collateral ligaments with medial collateral ligament fibers herniated through the medial capsule and occupying the medial compartment, which resulting in a locked knee. The author is not aware of any reports in the literature of this and presents this to raise awareness of another cause of knee locking.

Proprioception in anterior cruciate ligament-deficient and reconstructed knees.

Proprioceptive function of the knee was quantified and compared in three groups of patients: those with anterior cruciate ligament deficiency, with hamstring tendons-ligament augmentation device anterior cruciate ligament reconstructions, and with bone-patellar tendon-bone anterior cruciate ligament reconstructions. A total of 32 subjects, including 6 uninjured control subjects, were tested for threshold to perception of passive motion of the knee. All other sensory input was neutralized and testing occurred in the 30 degrees to 40 degrees range of knee flexion. The noninvolved contralateral knee served as a control for each subject. Each leg was moved at 0.5 deg/sec into flexion or extension in a random sequence. The variables of age, KT-1000 arthrometer scores, injury-to-surgery interval, injury-to-followup interval, and patient satisfaction were statistically analyzed for correlation with threshold to perception of passive motion of the knee. Control subjects showed no statistically significant differences in threshold between their two knees. The three test groups all showed significantly higher values in the involved knee compared with the noninvolved knee (P < 0.01). However, no statistically significant differences were found between the groups, including controls, with respect to mean threshold to perception of passive motion. According to these results, anterior cruciate ligament reconstruction did not improve proprioception in the patients in this study.

Analysis of proprioception in the posterior cruciate ligament-deficient knee.

The purpose of this study was to demonstrate loss of proprioception with posterior cruciate ligament (PCL) deficiency. Eight patients with isolated PCL-deficient knees were examined to determine whether or not the proprioceptive function of the knee joint was affected or impaired by the previous tear of the PCL. The patients were examined for perception of passive movement of the knee joint using a motorized apparatus which extended or flexed the patient's knee at a rate of 0.5 deg/s in a randomized sequence. The patient's normal contralateral knee was used as a control. This study demonstrated a significant difference in proprioception in the patient's PCL-deficient knee. All eight PCL-deficient knees clearly demonstrated slower perception of passive movement when compared with the contralateral normal knee. Injuries to the PCL resulting in impaired proprioception may play a role in knee instability, further damage and ultimately the degenerative changes frequently seen in the long-term follow-up of PCL-deficient knees.

Reliability of radiographic assessment of acromial morphology.

The most widely used radiographic classification system for acromial morphology identifies three distinct acromial shapes: type I (flat), type II (curved), and type III (hooked). The purpose of this study was to measure the interobserver and intraobserver reliability of determinations of acromial morphology as defined by this system. Between 1990 and 1992, one hundred twenty-six supraspinatus outlet radiographs were obtained from 126 patients by technicians from Triangle Orthopaedic Associates in Durham, N.C. Six fellowship-trained shoulder surgeons independently reviewed each radiograph and classified it as type I, II, or III on the basis of established guidelines. Two surgeons classified each film a second time in random order. Analysis of variance was performed to obtain coefficients for interobserver and intraobserver reliability. Consensus ratings were then used to classify the 126 radiographs into consensus type I, consensus type II, or consensus type III groups. Percentages of type I, II, and III individual ratings within each consensus group were determined. The intraobserver reliability coefficient was 0.888, interpreted as good to excellent reliability. The interobserver reliability coefficient was 0.516, interpreted as poor to fair reliability. Of the 126 radiographs, 26 (20.6%) were rated as consensus type I, 76 (60.3%) were rated as consensus type II, and 24 (19.1%) were rated as consensus type III. The reliability of observer ratings was lowest when delineation between acromial types II and III was required. The low interobserver reliability makes comparisons of studies by different authors difficult to interpret and obscures the true incidence of acromial morphologic types. It also questions reported correlations between acromial type and shoulder pathologic conditions. It is concluded that a system that incorporates more objective classification criteria and acknowledges the continuous nature of acromial morphologic types may improve interobserver reliability and validate the system's use in making clinical and surgical judgments.

Effects of an accelerated rehabilitation program after anterior cruciate ligament reconstruction with combined semitendinosus-gracilis autograft and a ligament augmentation device.

Forty patients with anterior cruciate reconstructions using semitendinosus and gracilis autografts and a ligament augmentation device were reviewed at a minimum of 20 months postoperatively to determine if an accelerated rehabilitation program was detrimental to intermediate follow-up results. The rehabilitation program included immediate full weightbearing, using crutches as aids for 2 weeks only, and a Generation II rehabilitation brace set at full range of motion for 2 weeks followed at 2 weeks by bicycle riding and strengthening exercises. Return to sports was allowed at 4 months for nonpivoting sports and at 6 months for level 1 sports involving pivoting. Thirty-seven patients were available for followup. At followup, three grafts were determined to be nonfunctional (KT-1000 arthrometer testing indicating > 4 mm of side-to-side difference). The other 34 patients had good or excellent results, with all returning to their preinjury levels of sport with a brace. Early accelerated rehabilitation after anterior cruciate ligament reconstruction with semitendinosus and gracilis tendon autograft and a ligament augmentation device does not seem to affect the results adversely. Results in this series were as good as or better than other series using the same reconstructive technique.

Large-scale analysis of gene expression, protein localization, and gene disruption in Saccharomyces cerevisiae.

We have developed a large-scale screen to identify genes expressed at different times during the life cycle of Saccharomyces cerevisiae and to determine the subcellular locations of many of the encoded gene products. Diploid yeast strains containing random lacZ insertions throughout the genome have been constructed by transformation with a mutagenized genomic library. Twenty-eight hundred transformants containing fusion genes expressed during vegetative growth and 55 transformants containing meiotically induced fusion genes have been identified. Based on the frequency of transformed strains producing beta-galactosidase, we estimate that 80-86% of the yeast genome (excluding the rDNA) contains open reading frames expressed in vegetative cells and that there are 93-135 meiotically induced genes. Indirect immunofluorescence analysis of 2373 strains carrying fusion genes expressed in vegetative cells has identified 245 fusion proteins that localize to discrete locations in the cell, including the nucleus, mitochondria, endoplasmic reticulum, cytoplasmic dots, spindle pole body, and microtubules. The DNA sequence adjacent to the lacZ gene has been determined for 91 vegetative fusion genes whose products have been localized and for 43 meiotically induced fusions. Although most fusions represent genes unidentified previously, many correspond to known genes, including some whose expression has not been studied previously and whose products have not been localized. For example, Sec21-beta-gal fusion proteins yield a Golgi-like staining pattern, Ty1-beta-gal fusion proteins localize to cytoplasmic dots, and the meiosis-specific Mek1/Mre4-beta-gal and Spo11-beta-gal fusion proteins reside in the nucleus. The phenotypes in haploid cells have been analyzed for 59 strains containing chromosomal fusion genes expressed during vegetative growth; 9 strains fail to form colonies indicating that the disrupted genes are essential. Fifteen additional strains display slow growth or are impaired for growth on specific media or in the presence of inhibitors. Of 39 meiotically induced fusion genes examined, 14 disruptions confer defects in spore formation or spore viability in homozygous diploids. Our results will allow researchers who identify a yeast gene to determine immediately whether that gene is expressed at a specific time during the life cycle and whether its gene product localizes to a specific subcellular location.

Isolation and expression of a gene specifying a cdc2-like protein kinase from the human malaria parasite Plasmodium falciparum.

A partially redundant oligonucleotide based on conserved protein sequences of cdk and cdc2-like proteins was used to isolate from genomic libraries of Plasmodium falciparum fragments of chromosome XIII carrying a 288-residue open-reading frame encoding a protein kinase sharing 57-58% identity with yeast p34cdc2. Based on sequence data, base composition and the striking similarity with other cdk and related proteins, four intervening sequences were identified. Their removal in vitro allowed expression of the gene, designated PfPK5, in Escherichia coli, the resulting product having kinase activity against casein and histone H1. Western blotting using a polyclonal antibody raised against the expressed protein showed that the kinase was located in the parasite's cytosol and was present in approximately constant amounts throughout the intra-erythrocytic asexual reproductive stage of the life cycle. The PSTAIRE region of the PfPK5 protein differs at three sites from that of p34cdc2, and the gene failed to complement cdc2/28 yeast mutants. However, Western blotting showed that the gene was not expressed in yeast, so this does not eliminate the possibility that it is the malarial version of cdc2.

Release of the subscapularis for internal rotation contracture and pain after anterior repair for recurrent anterior dislocation of the shoulder.

Ten patients who had an internal rotation contracture and pain after an anterior repair for recurrent dislocation of the shoulder were treated by release of the subscapularis muscle. For six of the patients, radiographs demonstrated severe osteoarthrotic changes in the shoulder as well. The release was done an average of eleven years after the original procedure, which, for most patients, had been a Putti-Platt repair. After release of the subscapularis, each patient had less pain in the shoulder and an average increase of 27 degrees of external rotation. Release of the subscapularis can offer relief of pain and of functional limitations associated with the symptoms caused by an internal rotation contracture after an anterior repair of the shoulder.

MEI4, a meiosis-specific yeast gene required for chromosome synapsis.

The MEI4 gene product is required for meiotic induction of recombination and viable spore production in the yeast Saccharomyces cerevisiae. DNA sequence analysis shows that the MEI4 gene encodes a 450-amino-acid protein bearing no homology to any previously identified protein. The MEI4 coding region is interrupted by a small intron located near the 5' end of the gene. Efficient splicing of the MEI4 transcript is not dependent on the MER1 protein, which is required for splicing the transcript of another meiotic gene, MER2. Expression of a mei4::lacZ fusion gene is meiosis-specific and depends on both heterozygosity at the mating-type locus and nutrient limitation. Northern (RNA) blot hybridization analysis suggests that MEI4 gene expression is regulated at the level of transcription. A functional MEI4 gene is not required for meiotic induction of transcription of the MER1, MER2, MEK1, RED1, SPO11, or RAD50 gene. Cytological analysis of mei4 mutant strains during meiotic prophase demonstrates that the chromosomes form long axial elements that fail to undergo synapsis. The meiosis II division is delayed in mei4 strains.

Open surgical techniques in the athlete's shoulder.

Treatment of the athlete's shoulder is one of the greatest challenges facing the orthopedic specialist. Surgical procedures, and in particular, the open surgical techniques presented in this article, are always a last resort of treatment. The primary treatment is always nonoperative with a particular emphasis toward physiotherapy. In selected instances in which patients have failed rehabilitation, the techniques that are presented can achieve a relatively high degree of success if particular attention is paid to the specific indications, approaches, and details of each technique. Open surgical techniques for rotator cuff tendonitis, instability, and unusual problems in the athlete's shoulder are presented.

Orthopaedic manifestations of blastomycosis.

The cases of seventy-two patients who had blastomycosis and were seen between 1926 and 1988 were retrospectively reviewed for involvement of the musculoskeletal system. Most patients were from rural rather than urban areas (almost a 2:1 ratio), and an especially large number were from northwestern Ontario or were native Indians (primarily Ojibwa). Bone was the second most common site of involvement (seventeen patients); in approximately one-half of these patients, the osseous site did not cause symptoms. Metaphyses of long bones and small bones were involved the most; the metaphyseal lesions tended to be eccentric, well circumscribed, and lytic. There were two deaths--the most recent, more than twenty years ago--of patients who had involvement of bones and joints; these patients, by modern standards, had had inadequate treatment. Treatment with amphotericin B and, more recently, with ketoconazole, in conjunction with operative treatment, was very effective.

Haemophilic arthropathy of the shoulder.

Among 41 adult haemophiliacs 15 suffered from shoulder symptoms. We examined 12 patients by radiography and ultrasound. Four had bilateral symptoms making a total of 16 symptomatic shoulders. Of these, 10 had abnormal ultrasound scans with eight having evidence of rotator cuff tears. Evidence of bicipital tendonitis was found in two. Pain with loss of range of movement and a positive impingement sign was the most reliable clinical indicator of a cuff tear. Joint incongruity and superior migration of the humeral head were the best radiographic indicators. Rotator cuff tears are a common component of haemophilic arthropathy of the shoulder.