Mitochondrial DNA damage is involved in apoptosis caused by pro-inflammatory cytokines in human OA chondrocytes.

OBJECTIVE: Pro-inflammatory cytokines play a pivotal role in cartilage destruction during the progression of osteoarthritis (OA). Additionally, these cytokines are capable to generate reactive oxygen and nitrogen species within chondrocytes. Mitochondrion is a prime target of oxidative damage and an important player in aging and degenerative processes. The purpose of the present study was to investigate whether these cytokines will alter the mitochondrial DNA (mtDNA) integrity and mitochondrial function in both normal and osteoarthritic human chondrocytes. DESIGN: Primary normal and osteoarthritic human chondrocyte cultures were exposed to various concentrations of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) for different time. Following exposure, chondrocytes were evaluated for mitochondrial DNA damage, ATP production, changes in mitochondrial transcription, and apoptosis. Adenoviral vectors were used to deliver DNA repair enzyme hOGG1 to mitochondria. RESULTS: Pro-inflammatory cytokines IL-1beta and TNF-alpha disturb mitochondrial function in human chondrocytes by inducing mitochondrial DNA damage, decreasing energy production and mitochondrial transcription, which correlated with the induction of apoptosis. Increased NO production was the key factor responsible for accumulation of mtDNA damage after cytokine exposure. Mitochondrial superoxide production was also enhanced following pro-inflammatory cytokine exposure. OA chondrocyte mitochondria were more susceptible to damage induced by pro-inflammatory cytokines then mitochondria from normal chondrocytes. Protection of human chondrocytes from mtDNA damage by the mitochondria-targeted DNA repair enzyme hOGG1 rescued mtDNA integrity, preserved ATP levels, reestablished mitochondrial transcription, and significantly diminished apoptosis following IL-1beta and TNF-alpha exposure. CONCLUSION: Mitochondrion is an important target in pro-inflammatory cytokine toxicity, maintaining of mitochondrial DNA integrity is necessary to prevent chondrocytes from apoptosis induced by IL-1beta and TNF-alpha.

Diminished mitochondrial DNA integrity and repair capacity in OA chondrocytes.

OBJECTIVES: Osteoarthritis (OA) is characterized by the failure of chondrocytes to respond to injury and perform the cartilage remodeling process. Human articular chondrocytes actively produce reactive oxygen and nitrogen species (ROS and RNS) capable of causing cellular dysfunction and death. A growing body of evidence indicates that mitochondrial dysfunction and mitochondrial DNA (mtDNA) damage play a causal role in disorders linked to excessive generation of oxygen free radicals. The aim of this study was to determine whether mtDNA damage was present in OA chondrocytes, and whether mtDNA repair capacity is compromised in OA chondrocytes following oxidative stress, leading to chondrocyte death. METHODS: Human articular cartilage was isolated from knee joints of cadavers available through the Anatomical Gifts Program at the University of South Alabama (normal donors) or OA patients undergoing total knee replacement surgeries (OA patients). Total DNA was isolated from either chondrocytes released following collagenase digestion, or from first passage chondrocytes grown in culture and exposed to ROS or RNS. mtDNA integrity and repair capacity were analyzed by quantitative Southern blot analysis, using a mtDNA-specific radioactive probe. Cell viability was determined by the trypan blue exclusion method. RESULTS: mtDNA damage was found in chondrocytes from OA patients compared to normal donors. It was accompanied with reduced mtDNA repair capacity, cell viability, and increased apoptosis in OA chondrocytes following exposure to ROS and RNS. CONCLUSIONS: These results indicate that mtDNA damage and poor mtDNA repair capacity for removing damage caused by oxidative stress may contribute to the pathogenesis of OA.

Viscoelastic studies of human subscapularis tendon: relaxation test and a Wiechert model.

Numerical techniques such as the finite element method employ the material constitutive laws for their analysis. With regards to finite element analysis involving viscoelastic solids, the Generalized Standard Linear Solid (Wiechert) model has been a popular choice among available constitutive laws. Although numerous models have been developed to specifically describe the viscoelastic behavior of tendons and ligaments, most of them have not been implemented in commercial finite element packages. This paper describes a stress relaxation test on the human subscapularis tendon, and then presents an approach for obtaining constitutive parameters of a Wiechert model for the human subscapularis tendon using experimental data from the aforementioned relaxation test. The approach is general and thus, can be applied to other tendons and ligaments, as well as any linear viscoelastic solid materials. The Wiechert model is required if finite element analysis using the commercial finite element package ANSYS is to be performed for a biomechanic structure composed of tendons and/or ligaments.

The relationships between instrumented measurements of ankle and knee ligamentous laxity and generalized joint laxity.

AIM: The purpose of this study was to evaluate whether lower extremity joint laxity is a function of a particular joint and/or a generalizable characteristic (trait) of the person. Validated instrumented measurements of ankle and knee joint-specific laxity in the same individual were correlated to determine whether a relationship exists. In addition, ankle and knee joint-specific laxity were correlated with generalized joint laxity using the modified Beighton mobility index. METHODS: Fifty-seven male and female athletes were studied. We examined dominant ankle laxity using an ankle arthrometer and dominate knee anterior laxity using the KT 2000. The dominant ankle was loaded in anteroposterior (AP) drawer and inversion-eversion (I-E) rotation. Laxity was measured as total AP displacement (millimeters) after +/-125 N of applied force and total I-E rotation (degrees) was measured after +/-4 N x m of applied torque. The dominant knee was loaded with an anterior drawer and laxity (millimeters) was measured after manual maximum displacement. RESULTS: Non-significant correlations were observed among the test variables for generalized joint laxity (0.21 to 0.37; P>0.05) and instrumented ankle and knee joint laxity (0.19 to 0.21; P>0.05). When examined by gender, no statistically significant correlations (0.05 to 0.40; P>0.05) were found for either generalized laxity or instrumented ankle and knee joint laxity. CONCLUSIONS: These results imply that ankle and knee joint laxity are joint-specific and not generalizable.

Upper and lower body strength in relation to underhand pitching speed by experienced and inexperienced pitchers.

The relation of legs, arms, shoulders, and grip strength with underhand pitching speed of experienced and inexperienced female pitchers was investigated. For 16 experienced female underhand pitchers and 16 inexperienced women with no softball experience (control group) leg and arm strength were measured using a Hydrafitness exercise machine. Grip strength was measured with a handgrip dynamometer. Underhand throwing speed was measured with a radar gun. Regression analysis showed arm and grip strength correlated with throwing speed (p < or = .05) for the experienced group. For the inexperienced control group, the only correlate of throwing speed was arm strength (p < or = .05). There was a significant difference between the two groups on all measures of strength and ball speed in favor of the experienced group (p < or = .05).

Once daily high-dose gentamicin to prevent infection in open fractures of the tibial shaft: a preliminary investigation.

BACKGROUND: Cephalosporin and aminoglycoside antibiotics are currently recommended for infection prophylaxis in high-energy open tibial shaft fractures. We evaluated cephalosporin in conjunction with once daily high-dose gentamicin as prophylaxis against infection in Gustilo types II and III open tibial shaft fractures. METHODS: Sixteen patients were identified in whom once daily gentamicin dosing was used as part of an antibiotic prophylaxis regimen in patients with types II and III open tibial shaft fractures. Cefazolin (1 g) and gentamicin (5 mg/kg) were given before operation. Antibiotic therapy was continued for 48 hours after definitive wound closure. Monitoring for gentamicin toxicity consisted of blood urea nitrogen (BUN) and creatinine levels, gentamicin trough levels, and a daily query for signs of prodromal ototoxicity. RESULTS: Average time to fracture union was 8 months. One superficial and two deep infections were observed. No patient showed signs of nephrotoxicity or ototoxicity. CONCLUSIONS: Our investigation suggests that this dosing regimen might be safe as prophylaxis against infection in open tibial shaft fractures and that it warrants further study.

The relationship of age, gender, and degenerative changes observed on radiographs of the shoulder in asymptomatic individuals.

Radiographs of the shoulders of 84 asymptomatic individuals aged between 40 and 83 years were evaluated to determine changes in 23 specific areas. Two fellowship-trained orthopaedic radiologists graded each area on a scale of 0 to II (normal 0, mild changes I, advanced changes II). Logistic regression analysis indicated age to be a significant predictor of change (p < 0.05) for sclerosis of the medial acromion and lateral clavicle, the presence of subchondral cysts in the acromion, formation of osteophytes at the inferior acromion and clavicle, and narrowing and degeneration of the acromioclavicular joint. Gender was not a significant predictor (p > 0.05) for radiological changes. Student's t-test determined significance (p < 0.05) between age and the presence of medial acromial and lateral clavicular sclerosis, subchondral acromial cysts, inferior acromial and clavicular osteophytes, and degeneration of the acromioclavicular joint. Radiological analysis in conditions such as subacromial impingement, pathology of the rotator cuff, and acromioclavicular degeneration should be interpreted in the context of the symptoms and normal age-related changes.

Heterotopic ossification of the adductor longus muscle presenting as dyspareunia.

Dyspareunia after heterotopic ossification of the adductor longus is a rare complication. We describe a patient with symptomatic heterotopic ossification of the adductor muscle that developed years after sustaining a fracture of the inferior pubic ramus in association with an injury to the adductor longus muscle. The patient's pain was reduced and his dyspareunia resolved after excision of the adductor longus heterotopic ossification and subsequent physical therapy.

Change in meniscal strain with anterior cruciate ligament injury and after reconstruction.

Meniscal injury has been well documented in association with injury to the anterior cruciate ligament. The purpose of this study was to evaluate the effect of anterior cruciate ligament transection and reconstruction on meniscal strain. Four differential variable reluctance transducer strain gauges were placed in the medial and lateral menisci of nine cadaveric knees. Each specimen was mounted to a six-degree-of-freedom knee testing device. Testing was conducted with the knee fully extended and at 45 degrees and 90 degrees of flexion, both with and without applied axial load. At each angle of flexion, an anterior and posterior tibial load was applied. Next, the anterior cruciate ligament was transected and the testing sequence was repeated. Finally, the ligament was reconstructed using a central one-third patellar tendon graft and the testing sequence was repeated. The results demonstrated statistically significant increases in meniscal strain in ligament-transected knees compared with intact specimens. A reduction in meniscal strain to a level similar to that detected in the ligament-intact knees was observed after anterior cruciate ligament reconstruction. These results have important clinical implications regarding the potentially deleterious effect of the anterior cruciate ligament-deficient knee on meniscal strain and the potential benefit of anterior cruciate ligament reconstruction.

Transesophageal echocardiography in quantification of emboli during femoral nailing: reamed versus unreamed techniques.

We quantified the embolic load to the lungs created with two different techniques of femoral nailing. Eleven patients with 12 traumatic femur fractures were randomized to reamed (7 fractures) and unreamed (5 fractures) groups. Intramedullary nailing was with the AO/ASIF* universal reamed or unreamed nail. Transesophageal echocardiography (TEE) was used to evaluate the quantity and quality of emboli generated by nailing. Data were analyzed using software that digitized the TEE images and quantified the area of embolic particles in each frame. The duration of each level of embolic phenomena (zero, moderate, severe) was used to determine total embolic load with various steps (fracture manipulation, proximal portal opening, reaming, and nail passage). Manual grading of emboli correlated highly with software quantification. Our data confirm the presence and similarity of emboli generation with both methods of intramedullary nailing. Unreamed nails do not protect the patient from pulmonary embolization of marrow contents.

The effect of isometric graft posterior cruciate ligament reconstruction on anterior tibial translation.

Eight fresh-frozen cadaver knees were studied to evaluate whether an isometrically placed posterior cruciate ligament (PCL) graft restores normal posterior tibial translation without overconstraining anterior tibial translation. Each knee was tested with a three-axis load cell in the intact state, after PCL sectioning, and after PCL reconstruction. After PCL reconstruction, posterior tibial displacement was restored to values observed in the intact state for all flexion angles except 60 degrees and 90 degrees. Anterior tibial translation was not significantly changed for any of the three states. These results indicate isometric reconstruction of the PCL significantly reduces posterior tibial translation without overconstraining anterior tibial translation.

The intra-articular component of the subscapularis tendon: anatomic and histological correlation in reference to surgical release in patients with frozen-shoulder syndrome.

Recently, arthroscopic surgical techniques have been reported for release of glenohumeral capsular contractures in selected patients with frozen-shoulder syndrome. The purpose of the current study was to assess the anatomy and histology of the subscapularis muscle, including its intra-articular component. Ten cadaveric shoulders underwent arthroscopy and dissection, and an additional 3 specimens underwent histological analysis. To provide clinical correlation, 35 patients who underwent arthroscopic capsular release completed a modified questionnaire developed by the authors. The anterior-posterior diameter and cephalad-caudad height of the intra-articular subscapularis tendon (IASS) averaged 5 mm and 11 mm, respectively. This represented 83% of the sagittal diameter and 25% of the total height of the subscapularis at the point of release. Histological analysis confirmed these anatomic observations. All patients had reduction of pain and improved function at an average of 22 months after surgery. Only 1 patient had mild subjective symptoms of instability. The current study indicates that the IASS can be released during arthroscopic capsular release for frozen shoulder with minimal risk of secondary anterior instability to the patient.

Acute compartment syndrome after rupture of the medial head of the gastrocnemius muscle.

Rupture of the gastrocnemius muscle is an uncommon injury, with most cases occurring in athletically active individuals. The presentation of a gastrocnemius rupture is the acute onset of calf pain and subsequent ecchymosis. Most of these injuries can be treated symptomatically with good results. We present an unusual case of gastrocnemius muscle tear complicated by acute compartment syndrome. Physicians need to be aware of this potentially devastating complication of gastrocnemius rupture.

Instrumented measurement of anteroposterior and inversion-eversion laxity of the normal ankle joint complex.

Manual examination is the most common method for the evaluation of ankle anteroposterior (AP) and inversion-eversion (I-E) laxity. Objective assessment data of normal ankle laxity must be provided before comparison with an injured ankle can be made. The purpose of this study was to compare AP translation and I-E rotation at three force loads between dominant and nondominant ankles and to assess the test-retest reliability of a portable arthrometer in obtaining these measurements. The arthrometer consists of a frame that is fixed to the foot, a pad that is attached to the tibia, and a load-measuring handle that is attached to the foot plate through which the load is applied. A six-degrees-of-freedom spatial kinematic linkage system is connected between the tibial pad and the foot frame to measure motion. Instrumented measurement testing of total AP displacement and I-E rotation of both ankles was performed in 41 subjects (21 men and 20 women; mean age, 23.8 +/- 4.4 years). Subjects had no history of ankle injury. Subjects were tested in the supine position while lying on a table with the knee secured in extension and the foot positioned at 0 degrees of flexion. Laxity was measured from total AP displacement (millimeters) during loading to 125 N of AP force and from total I-E rotation (degrees of range of motion) during loading to 4000 N-mm. Reliability was evaluated by calculating intraclass correlation coefficients (2,1) at 75 N, 100 N, and 125 N of AP force and at 2000, 3000, and 4000 N-mm torque loads. Mean differences for displacement and rotation between the dominant and nondominant ankles at each of the force and torque loads were analyzed by dependent t-tests. For both the dominant and nondominant ankles, respectively, the reliability coefficients at each of the force loads for AP displacement (range, 0.82-0.89) and I-E rotation (range, 0.86-0.97) were high. The t-test analyses showed no significant differences (P > or = 0.05) for total AP displacement or I-E rotation between the dominant and nondominant ankles at any of the force loads. The results are clinically useful in providing information about the reliability of measures at different AP and I-E force loads using a portable ankle ligament arthrometer.

The low anterior five-o'clock portal during arthroscopic shoulder surgery performed in the beach-chair position.

We evaluated the difficulty, accuracy, and safety of establishing a low anterior 5-o'clock portal for anterior capsulolabral repair in patients positioned in the beach-chair position during shoulder arthroscopy. An initial 5-o'clock portal was created using an inside-out technique as described by Davidson and Tibone. During establishment of the portal, significant force was required to lever the humeral head laterally, and chondral indentations were noted in several specimens. Because of the difficulty noted establishing the 5-o'clock portal using an inside-out technique, we attempted to establish a 5-o'clock anterior portal using an outside-in technique. Seven fresh-frozen cadaveric shoulders underwent shoulder arthroscopy in the beach-chair position. After the establishment of a 3-o'clock portal, a specially constructed guide was used to place a pin at the 5-o'clock position. The distances of the pins from the cephalic vein and the musculocutaneous and axillary nerves were recorded. The bottom (5-o'clock position) and top (3-o'clock position) pins varied from 12 to 20 mm from the musculocutaneous and axillary nerves. The bottom pin was located within 2 mm of the cephalic vein and varied from medial to lateral in different specimens. We do not recommend the use of a 5-o'clock portal using an inside-out or outside-in technique for patients positioned in the beach-chair position during shoulder arthroscopy because of the potential for cephalic vein or articular cartilage injury.

An arthroscopic technique for treating patients with frozen shoulder.

Forty-three patients with a diagnosis of primary or secondary frozen shoulder who had symptoms for an average of 12 months and failed conservative treatment of at least 12 weeks of physical therapy, were treated with an arthrosopic capsular release. On completion of standard shoulder arthroscopy, intra-articular cautery was used to completely divide the anterior-inferior capsule, the intra-articular portion of the subscapularis tendon, and the middle glenohumeral, the superior glenohumeral, and the coracohumeral ligaments. The subacromial space was inspected in all patients. Eighteen patients had extensive subacromial fibrosis that required debridement. Subacromial decompression was reserved for patients with evidence of an acromial spur seen at the time of arthroscopy. Postoperatively, all patients showed substantial gains in shoulder range of motion, as well as diminished shoulder pain. Thirty-five patients completed a telephone survey at an average of 22 months after surgery. The average modified shoulder score was 19 (scale, 13 to 65), with 83% of patients indicating that their shoulder was normal or caused only mild symptoms. In conclusion, the authors believe that arthroscopic capsular release is an effective and safe alternative to manipulation in patients with a recalcitrant frozen shoulder.

Frozen shoulder syndrome: diagnostic and treatment strategies in the primary care setting.

The term "frozen shoulder" has been used to describe an array of clinical conditions. The authors consider a patient as meeting the criteria of primary or secondary frozen shoulder syndrome if he/she has a clinical history of worsening painful shoulder motion loss of at least 1 month duration and a physical examination documenting painful restricted shoulder motion. In the evaluation of the patient with suspected FSS, initial screening shoulder radiographs are required to exclude other conditions. The physical examination of the frozen shoulder patient should include observation, cervical examination, assessment of range of motion, and the use of provocative testing. The treatment of the patient with FSS should include preventative education, various medications including NSAIDS and oral corticosteroids, physical therapy, and finally, for the patient with refractory symptoms, surgical intervention. For those patients necessitating surgical intervention, the authors recommend a selective arthroscopic capsular release.

An in vitro analysis of patellofemoral contact areas and pressures following procurement of the central one-third patellar tendon.

Patients have complained of pain after the use of the central one-third patellar tendon for reconstruction of the anterior cruciate ligament-deficient knee. This study investigated the effect on patellofemoral contact areas and pressures of harvesting the central 10 mm of the patellar tendon in five cadaveric knees. Isometric quadriceps forces were applied to produce approximately 30% of reported maximum voluntary extension moments at the knee. Using Fuji pressure-sensitive film, measurements were recorded for three states: the normal knee, after the graft removal, and after the tendon was closed. Contact areas and pressures were measured at 20 degrees, 30 degrees, 60 degrees, and 80 degrees of knee flexion in each specimen. Tests of the reproducibility of our methods were performed. Average patellofemoral contact areas for three states ranged from 1.6 cm2 at 20 degrees of knee flexion to 3.0 cm2 at 60 degrees. The average patellofemoral contact pressures ranged from 1.9 MPa at 20 degrees of knee flexion to 3.0 MPa at 30 degrees. At each flexion angle there were no significant differences in average patellar contact area or pressure for the three states (P < 0.05). These results suggest that neither harvesting the central 10 mm of the patellar tendon, nor closing the gap, significantly alters patellofemoral contact area or pressure.