Load-deformation characteristics of cadaver patellae: Relationship to intraosseous pressure.

BACKGROUND: Anterior knee pain can arise from several sources. One of the main sources of pain in patients with anterior knee pain is the patella. Increased patellofemoral joint loading is the prime source of patellar pain. Elevated intraosseous pressures have been measured in painful patellae and increasing the intraosseous fluid pressure in the patella causes pain. Whether elevated fluid pressure is an independent source of pain or if the patellar deformation under load leads to elevated pressure and pain has not been determined. Our hypothesis was that the patella deforms measurably under physiologic loads and that intraosseous pressure increase is related to that deformation. The relationship may be linear as measured by correlation or nonlinear as measured by the sum of squared error. METHODS: Part I: Assessment of patellar load-deformation profiles were obtained in 2 intact cadaver patellae and 1 bisected patella under physiologic loads. Part II: Measurements of intraosseous pressure were obtained in 9 cadaver patellae as the patellae were compressed with physiologic loads. Pressures were recorded at sequential levels of anterior-posterior patellar compression. FINDINGS: Cadaver patellae compress up to 3.5 mm in the anterior-posterior plane. Compression with physiologic forces raises intraosseous pressure to more than 40 mmHg. INTERPRETATION: Load-deformation of cadaver patellae results in deformation and an increase in intraosseous pressure. These findings may help explain previous studies of patellofemoral pain where elevated patellar intraosseous pressures have been found in vivo.

Assessment of musculoskeletal toxicity 5 years after therapy with levofloxacin.

BACKGROUND: Safety concerns for fluoroquinolones exist from animal studies demonstrating cartilage injury in weight-bearing joints, dependent on dose and duration of therapy. For children treated with levofloxacin or comparator in randomized, prospective, comparative studies for acute otitis media and community-acquired pneumonia, this 5-year follow-up safety study was designed to assess the presence/absence of cartilage injury. METHODS: Children enrolled in treatment studies were also enrolled in a 1-year follow-up safety study, which; focused on musculoskeletal adverse events (MSAE). Those with persisting MSAEs, protocol-defined musculoskeletal disorders, or of concern to the Data Safety and Monitoring Committee were requested to enroll in four additional years of follow-up, the subject of this report. RESULTS: Of the 2233 subjects participating in the 12-month follow-up study, 124 of 1340 (9%) of the levofloxacin subjects, and 83 of 893 (9%) of the comparator subjects were continued for 5-year posttreatment assessment. From children identified with an MSAE during years 2 through 5 posttreatment, the number that were "possibly related" to drug therapy was equal for both arms: 1 of 1340 for levofloxacin and 1 of 893 for comparator. Of all cases of MSAE assessed by the Data Safety and Monitoring Committee at 5 years' posttreatment, no case was assessed as "likely related" to study drug. CONCLUSIONS: With no clinically detectable difference between levofloxacin- and comparator-treated children in MSAEs presenting between 1 and 5 years in these safety studies, risks of cartilage injury with levofloxacin appear to be uncommon, are clinically undetectable during 5 years, or are reversible.

Long-term functional outcome after lateral patellar retinacular release in adolescents: an observational cohort study with minimum 5-year follow-up.

BACKGROUND: Lateral patellar retinacular release has been recommended for patients with patellar tilt, tight lateral retinaculum, patellar subluxation, patellar dislocation, and patellofemoral pain. Studies of long-term outcomes after lateral release are limited, especially for differing indications. HYPOTHESIS: Adolescents do well after lateral retinacular release in the 5- to 22-year time frame. METHODS: Patients having undergone lateral retinacular release between the years of 1981 and 1999 were contacted. Evaluation was by the Cincinnati and Lysholm scales and by level of satisfaction and need for reoperation. RESULTS: One hundred forty knees were studied. Mean age at operation was 15.4 years (SD, 2.7 years). Average follow-up was 8.5 (SD, 4.1 years; range, 5.2-22.5 years). Twenty-five patients had needed reoperation, indicating failure of the index operation. Kaplan-Meier survivorship was 78% at 15 years. Cincinnati and Lysholm scores indicated well-functioning knees in those not requiring reoperation. Overall satisfaction improved as time from operation increased. Comparisons were made between the group requiring reoperation and those who did not. Focus was placed on knees with patellar maltracking or tilt versus patellar instability and between males and females. No differences were found among groups for reoperation rate, level of satisfaction, average Lysholm score, or average Cincinnati score. There were no differences in demographics or outcome measures between patients with patellar instability and those with tilt. Instability patients trended toward higher reoperation rates than did tilt patients, but the difference was not significant. There were no differences between males and females. CONCLUSION: The majority of patients are satisfied with their knee 5 to 22 years after lateral patellar retinacular release and scored well on questions rating knee health and function.

Treatment of painful accessory navicular: a modification to simple excision.

An accessory tarsal navicular ossicle may produce pain and tenderness despite conservative treatment modalities. This condition causes pain along the medial arch and limitations of activities. This described modification of the Kidner procedure and simple excision technique keeps the tendon insertion intact while restoring some of the normal biomechanical relationships. In addition, this modification has the theoretical advantage of enhancing dynamic support of the longitudinal arch, and by maintaining the continuity of the posterior tibial tendon, a shorter period of immobilization is required. All patients at the most recent follow-up showed improvement, with 11 of 13 patients having excellent results with long-term follow-up.

Comparative safety profile of levofloxacin in 2523 children with a focus on four specific musculoskeletal disorders.

BACKGROUND: Fluoroquinolones, including levofloxacin, have not been recommended for use in children largely because studies in juvenile laboratory animals suggest there may be an increased risk of fluoroquinolone-associated cartilage lesions. A large prospective trial is needed to assess the risks associated with using levofloxacin in children. OBJECTIVE: Assess the safety and tolerability of levofloxacin therapy in children based on observations for 1 year after therapy. METHODS: Safety data were collected in children who participated in 1 of 3 efficacy trials (N = 2523) and a subset of these children who also subsequently participated in a long-term 1-year surveillance trial (N = 2233). Incidence of adverse events in children randomized to receive levofloxacin versus nonfluoroquinolone antibiotics was compared. Based on assessments by treating physicians and an independent data safety monitoring committee, events related to the musculoskeletal system were further categorized as 1 of 4 predefined musculoskeletal disorders (arthralgia, arthritis, tendinopathy, gait abnormality) considered most likely clinical correlates of fluoroquinolone-associated cartilage lesions observed in laboratory animals. RESULTS: Levofloxacin was well tolerated during and for 1 month after therapy as evidenced by similar incidence and character of adverse events compared with nonfluoroquinolone antibiotics. However, incidence of at least 1 of the 4 predefined musculoskeletal disorders (largely due to reports of arthralgia) was greater in levofloxacin-treated compared with nonfluoroquinolone-treated children at 2 months (2.1% vs. 0.9%; P = 0.04) and 12 months (3.4% vs. 1.8%; P = 0.03) after starting therapy. CONCLUSIONS: The incidence of 1 or more of the 4 predefined musculoskeletal disorders identified in nonblinded, prospective evaluations, was statistically greater in levofloxacin-treated compared with comparator-treated children.

Comparison of standing balance between female collegiate dancers and soccer players.

STUDY DESIGN: This study was designed as a comparison study of two cohorts. OBJECTIVES: The hypothesis of this study was that soccer players and dancers have different balance abilities and that these differences could be objectively measured using center of pressure measurements. BACKGROUND: Center of pressure (COP) measurements are reproducible and have been validated in the literature for assessing standing balance. The literature does not provide sensitive enough techniques for discriminating between two groups of athletes with excellent standing balance. METHODS AND MEASURES: A Matscan pressure mat (Tekscan, Boston, MA) was used to compare COP change variability between 32 female collegiate soccer players and 32 dancers. COP was used to calculate sway index, center acquisition time, sway path length and sway velocity as measures of standing balance. RESULTS: The dancers had significantly better balance scores (p<0.05) in 5 of 20 balance tests. Results for the remaining 15 balance tests were not significantly different. CONCLUSION: These data show that standing balance characteristics of dancers and soccer players can be objectively measured using COP data. Dancers have certain standing balance abilities that are better than those of soccer players. The COP measurements in this study can be used as a tool in future studies investigating standing balance in different groups of athletes.

Patellofemoral pain syndrome: evaluation of location and intensity of pain.

OBJECTIVES: To identify the sites and intensity of pain in patients with patellofemoral pain syndrome. METHOD: A prospective cohort study was conducted at an academic sports medicine practice in Boston, Massachusetts. All patients met inclusion criteria and were enrolled and evaluated during the study time frame. A single sports medicine orthopaedic surgeon examined a consecutive sample of patients with patellofemoral pain not explained by one of several well-defined anterior knee pain diagnoses. The study group consisted of 100 patients (75 females, 25 males) with median age of 14 years. Eleven discrete locations were palpated for tenderness. Hamstring tightness was evaluated by measuring the popliteal angle. Patients reported intensity of pain using a 0- to 9-point ordinal scale. Regression and nonparametric statistical methods were used. RESULTS: The most common site of pain was the patella during anterior-posterior compression (90 patients), followed by the distal pole of the patella, the medial plica, and the nonarticular medial femoral condyle. Median "worst pain" intensity was 6 out of a possible 9. The most common site of "worst pain" was also the patella in compression (63 patients). Median duration of symptoms was 10 months, with an interquartile range of 3 to 20 months. Pain intensity was inversely correlated with duration of symptoms (P < 0.01). CONCLUSIONS: In these patients with patellofemoral pain syndrome, the major source of pain was the patella subchondral bone.

Elbow disorders in throwing athletes.

Skeletally immature throwing athletes are injured when they throw too frequently or use throwing styles and pitches that overstress their elbows. Despite safety guidelines for throwing that recommend throwing more than 300, but less than 600, pitches per season, compliance is almost impossible to monitor, given multiple opportunities for throwing abuse away from organized, supervised league play. All throwers should avoid the side-arm throwing style. Pitchers should not play in multiple leagues, should not play hard-throwing positions when not pitching, and should not pitch when having elbow or shoulder pain. When the elbow becomes painful, pitching should cease and a thorough evaluation performed. Once the diagnosis is made, appropriate nonoperative treatment is undertaken. Operative intervention in this age group uncommonly is needed. Rehabilitation includes identifying and eliminating causative risk factors. Educating the athlete, coach, and parents results in a longer, pain-free throwing career and enhanced enjoyment of the sport.

Tendon or joint disorders in children after treatment with fluoroquinolones or azithromycin.

BACKGROUND: Fluoroquinolones (FQs) have been infrequently used in children, largely because of concern that these agents can cause lesions of the cartilage in juvenile animals. However, the relevance of this laboratory observation to children treated with FQs is unknown. A retrospective, observational study was conducted to assess the incidence and relative risk of tendon or joint disorders (TJDs) that occur after use of selected FQs compared with azithromycin (AZ), a drug with no known effect on cartilage or tendons in humans or animals. METHODS: An automated database was searched to identify patients younger than 19 years who had been prescribed ofloxacin (OFX), levofloxacin, ciprofloxacin (CPX), or AZ. Potential cases of TJD occurring within 60 days of a prescription of one of the study drugs were identified based on assignment of a claims diagnosis consistent with a TJD within this period. Verified cases were identified by a blinded review of abstracts of medical records from subjects identified as potential cases. RESULTS: The incidence of verified TJD was 0.82% for OFX (13 of 1593) and CPX (37 of 4531) and was 0.78% for AZ (118 of 15,073). The relative risk of TJD for OFX and CPX compared with AZ was 1.04 (95% confidence interval, 0.55 to 1.84) and 1.04 (95% confidence interval, 0.72 to 1.51), respectively. The distributions of claims diagnoses and time to onset of TJD were comparable for all groups. The most frequently reported category of TJD involved the joint followed by tendon, cartilage and gait disorder. CONCLUSIONS: In this observational study involving more than 6000 FQ-treated children, the incidence of TJD associated with selected FQ use in children was <1% and was comparable with that of the reference group, children treated with AZ.

Does football cause an increase in degenerative disease of the lumbar spine?

Degenerative disease of the lumbar spine is exceedingly common. Whether any specific activity increases the likelihood of developing degenerative disc disease (DDD) or facet degeneration (FD) has enormous implications. Within the field of occupational medicine there are specific activities, occupations, and morphologic characteristics that have been related to low back pain. Several specific risk factors have been conclusively linked to low back pain, and in particular DDD and FD. Within the sport of American football, there has long been the feeling that many athletes have or will develop low back pain, DDD, and FD. Proving that certain risk factors present in football will predictably lead to an increase in LBP, DDD, and FD is more difficult. At this time, it can be said that football players, in general, increase their risk of developing low back pain, DDD, and FD as their years of involvement with their sport increase. Because specific spine injuries like fracture, disc herniation, and spondylolysis are more frequent in football players, the resulting DDD and FD are greater than that of the general population. The weightlifting and violent hyperextension that are part of American football are independent risk factors for degenerative spine disease.