Long-term MRI findings in operated rotator cuff tear.

PURPOSE: To describe magnetic resonance imaging (MRI) findings at long-term follow-up after rotator cuff (RC) tear using standard MRI sequences without fat saturation. MATERIAL AND METHODS: Twenty-eight patients aged 55.8+/-7.6 underwent MRI examination 4.6+/-2.1 years after surgery for RC tear. Standard sequences in oblique coronal, oblique sagittal, and axial planes were obtained. The RC, including re-tears and tendon degeneration, was independently evaluated by two observers. Thickness of the supraspinatus tendon and narrowing of the subacromial space were measured. The clinical outcome was evaluated with the Constant score and compared with the MRI findings. RESULTS: The RC tear was traumatic in 18 (64%) patients and degenerative in 10 (36%). At follow-up, 11 (39%) had normal RC tendons with good clinical outcome. Four (14%) patients had painful tendinosis without RC tear. A full-thickness RC tear was found in 7 (25%) patients and a partial tear in 6 (21%). In one patient with a full-thickness tear, and in two with partial tear, tendinosis was found in another of the RC tendons. The subacromial space was narrowed in 13 (46%) of the patients. A narrowing of the subacromial space correlated with re-tear (P<0.05). CONCLUSIONS: The RC may be evaluated with standard MRI sequences without fat saturation at long-term follow-up. A normal appearance of the RC is correlated with good clinical outcome, while re-tear and tendinosis are associated with pain.

Normal and pathological adaptations of articular cartilage to joint loading.

Joints are functional units that transmit mechanical loads between contacting bones during normal daily or specialized activities, e.g., sports. All components of the joint, i.e. articular cartilage, bone, muscles, ligaments/tendons and nerves, participate in load transmission. Failure in any of these components can cause joint malfunction, which, in turn, may lead to accumulation of damage in other joint components. Mechanical forces have great influence on the synthesis and rate of turnover of articular cartilage molecules, such as proteoglycans (PGs). Regular cyclic loading of the joint enhances PG synthesis and makes cartilage stiff. On the other hand, loading appears to have less evident effects on the articular cartilage collagen fibril network. Continuous compression of the cartilage diminishes PG synthesis and causes damage of the tissue through necrosis. The prevailing view is that osteoarthrosis (OA) starts from the cartilage surface through PG depletion and fibrillation of the superficial collagen network. It has also been suggested that the initial structural changes take place in the subchondral bone, especially when the joint is exposed to an impact type of loading. This in turn would create an altered stress pattern on joint surfaces, which leads to structural damage and mechanical failure of articular cartilage. The importance of the neuromuscular system to the initiation and progression of OA is still poorly understood. Many surgical extra- and intra-articular procedures have been used for the treatment of OA. Although some of the new methods, such as autologous chondrocyte transplantation and mosaicplasty, have given good clinical results, it is reasonable to emphasize that the methods still are experimental and more controlled studies are needed.

Tourniquet-induced enmg changes in arthroscopic anterior cruciate ligament reconstruction. A comparison of low and high-pressure tourniquet systems.

BACKGROUND AND AIMS: The use of a tourniquet during surgery is associated with a risk of neurological disorders. We compared whether a new tourniquet system using low pressure (250 mmHg) is safer than a standard tourniquet system using higher inflation pressure (350 mmHg). MATERIALS AND METHODS: Thirty-one patients (ASA I-II), ages 16-48 years, were studied with ENMG preoperatively and 3 weeks postoperatively following arthroscopic anterior cruciate ligament reconstruction. Tourniquet times varied between 30 and 146 min. RESULTS: Postoperative slowing of motor and sensory conduction was observed, as well as an increase of the minimum peroneal F-response and tibial H-reflex latencies. The sensory amplitude of the sural nerve decreased. Vastus medialis of the quadriceps femoris muscle showed a reduced interference pattern in ENMG in maximal voluntary effort postoperatively. No differences were found in measured results between the low and high pressure tourniquet systems. CONCLUSIONS: Slight postoperative ENMG alterations were demonstrated but the use of both tourniquet systems is safe within the limit of tourniquet times of less than 2 h.

Dislocation of the proximal tibiofibular joint.A new method for fixation.

We introduce a new method for fixation of a rare, isolated, proximal tibiofibular dislocation. One third of the biceps femoris muscle tendon was used for fixation of the dislocated proximal fibular head. The fixation was achieved by using a soft threaded interference ACL screw.

In vivo characterization of indentation stiffness of articular cartilage in the normal human knee.

Previous laboratory measurements showed topographical variation in the properties of articular cartilage in several animal species and in humans. In this study we characterize for the first time the topographical variation of the stiffness of the human knee articular cartilage in vivo using a novel arthroscopic indentation instrument. The instrument indicates the stiffness in the form of force (Newtons) by which the tissue resists the constant deformation (300 microm) produced by the small (1-mm diameter) cylindrical indenter. Measurements were carried out at eight sites in the knee joint of 20 persons who had intact cartilage in the arthroscopic examination. The stiffest cartilage (5.6 +/- 1.2 N, mean +/- SD) was located in the lateral condyle of the femur, whereas the softest cartilage (2.4 +/- 0.8 N) was in the medial plateau of the tibia. In general, the cartilage stiffness was higher in the femur than in the tibia (p < 0. 01) or in the patella (p < 0.01). In the femur, the condyles were stiffer than the patellar surface (p < 0.01). The stiffness variation was consistent with earlier biphasic indentation analyses of laboratory measurements with the knee joint cartilage of cadavers. This study provides baseline data for characterization of cartilage stiffness in pathological situations or follow-up of the cartilage quality after surgical interventions.

Markers of cartilage and synovial metabolism in joint fluid and serum of patients with chondromalacia of the patella.

OBJECTIVE: To further our understanding of the pathogenesis of chondromalacia of the patella (CM), we have studied the release into knee joint fluid and serum, obtained from patients with CM, of molecules associated with the metabolism of joint cartilage matrix and synovium. METHODS: Interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), stromelysin-1 (MMP-3), interstitial collagenase (MMP-1), tissue inhibitor for metalloproteinases-1 (TIMP-1), phospholipase activity A2 (PLA2), hyaluronan (HA), aggrecan fragments (AGN) and antigenic keratan sulfate (KS) were quantified in knee joint lavage fluid from 96 patients with CM; KS and HA also was measured in serum. Chondromalacia was graded on a scale of I to IV according to Outerbridge (1961). The histopathology of the synovial membrane close to the patellofemoral joint was evaluated. Control samples were obtained from nine patients with knee pain presenting with arthroscopically normal knee joints. RESULTS: The concentrations of MMP-3, MMP-1 and TIMP-1 proteins in joint lavage fluid were increased in advanced (grade IV) CM, compared with controls. Levels of MMP-1 in lavage fluid correlated with the severity of CM (r = 0.38, P < 0.01) and MMP-1 and MMP-3 concentrations correlated with each other (r = 0.45, P < 0.001). TIMP-1 was elevated in grade IV CM compared with grades II and III CM (P < 0.02, P < 0.01). Interleukins (IL-1 alpha, IL-1 beta and IL-6) showed no significant change in CM. The lavage fluid level of PLA2 increased with the severity of CM (r = 0.40, P < 0.001). Serum KS was higher in CM IV than in controls (P = 0.05), while lavage fluid KS concentration was elevated in CM I (P = 0.04). There were no differences in the lavage fluid levels of AGN and HA between the different study groups. Synovium showed slight or moderate histological signs of inflammation in 9% of CM patients. CONCLUSION: The changes in the release and activity of these marker molecules from serum and synovial fluid may reflect changes in the metabolism of articular cartilage and synovium in CM, that are consistent with those observed in early-stage tibiofemoral cartilage changes in OA.

Metabolic effects of a low-pressure tourniquet system compared with a high-pressure tourniquet system in arthroscopic anterior crucial ligament reconstruction.

BACKGROUND: Bloodless field is an integral part of orthopedic surgery. Use of tourniquet is associated with a risk of skeletal muscle ischemia and reperfusion injury. The purpose of this prospective, open-randomized study was to determine if the use of a tourniquet system using low pressure, with a wide, curved cuff connected to a microprocessor pump is safer than a standard tourniquet system with a narrow, straight cuff using higher inflation pressures. METHODS: Test parameters used as markers of muscular injury and anaerobic metabolism were femoral vein blood lactate, pH, pCO2, pO2, potassium, aspartate aminotransferase activity, myoglobin, creatine kinase and creatine kinase-MM activity levels after release of tourniquet. Twenty-six ASA I-II patients were studied. RESULTS: Tourniquet times varied between 30 and 144 min. Deflation of the tourniquet caused a significant release of lactate, myoglobin and potassium detected in the femoral vein blood. pCO2 increased, but pH and pO2 decreased after tourniquet deflation. There were no differences between the study groups. The tourniquet time showed a significant correlation with femoral vein lactate. CONCLUSION: The main finding of this study was that the metabolic changes were more pronounced with the longer tourniquet time. The results of the study did not show any difference on metabolic markers of muscular injury during the first hour after release of tourniquet between the two tourniquet systems.

Collagen crosslinks in chondromalacia of the patella.

The aim of the study was to determine collagen concentration and collagen crosslinks in cartilage samples from chondromalacia of the patella. To study the extracellular matrix alterations associated to chondromalacia, we determined the concentration of collagen (hydroxyproline) and its hydroxylysylpyridinoline and lysylpyridinoline crosslinks from chondromalacia foci of the patellae in 12 patients and 7 controls from apparently normal cadavers. The structure of the collagen network in 8 samples of grades II-IV chondromalacia was examined under polarized light microscopy. The full-thickness cartilage samples taken with a surgical knife from chondromalacia lesions did not show changes in collagen, hydroxylysylpyridinoline and lysylpyridinoline concentration as compared with the controls. Polarized light microscopy showed decreased birefringence in the superficial cartilage of chondromalacia lesions, indicating disorganization or disappearance of collagen fibers in this zone. It is concluded that the collagen network shows gradual disorganization with the severity of chondromalacia lesion of the patella without changes in the concentration or crosslinks of collagen.

Hill-Sachs lesion: sonographic detection.

OBJECTIVE: To determine the value of ultrasonography (US) in the detection of Hill-Sachs lesion of the humerus in comparison with double-contrast computed tomographic arthrography (CTA) and with arthroscopy. DESIGN AND PATIENTS: US and CTA were performed on 92 patients, 86 of whom subsequently underwent arthroscopy. The findings of US, CTA and arthroscopy in these 86 patients in the diagnosis of Hill-Sachs lesion were analyzed. RESULTS AND CONCLUSIONS: In the detection of Hill-Sachs lesion US showed a sensitivity of 91% (21 of 23), a specificity of 95% (60 of 63) and an accuracy of 94% (81 of 86) when compared with CTA, and a sensitivity of 94% (18 of 19), specificity of 91% (61 of 67) and accuracy of 91% (79 of 86) when compared with arthroscopy. In only 2% (2 of 86) of patients was there reduced visualization because of restriction of movement. Hill-Sachs lesion and its relationship to the humeral head can be reliably diagnosed with US.

Site and size of rotator-cuff tear. Findings at ultrasound, double-contrast arthrography, and computed tomography arthrography with surgical correlation.

RATIONALE AND OBJECTIVES: The authors discuss findings of ultrasound (US), double-contrast arthrography (AG), and contrast computed tomography arthrography (CTA) in assessing precise site and size of rotator-cuff tears. METHODS: Eighty-six patients were compared prospectively in a masked fashion; the results of surgery were studied in 25 patients and the results of arthroscopy were studied in 61 patients. RESULTS: Ultrasound detected 80% (8 of 10) of the partial-thickness tears and 90% (18 of 20) of the full-thickness tears. Arthrography and CTA had identical results with 70% sensitivity (7 of 10) in partial-thickness tears; AG showed 90% (18 of 20) and CTA 95% (19 of 20) of the full-thickness tears. Arthrography had two false-positive findings, and US and CTA had one each. The size of a tear could be evaluated correctly with AG in 30% (9 of 30), with US in 70% (21 of 30) and with CTA in 76% (23 of 30). More extensive tears were encountered at US than had been found at surgery in 2% (2 of 86) and less extensive tears in 9% (8 of 86); CTA depicted more extensive tears in 2% (2 of 86) and less extensive tears in 6% (6 of 86), respectively. The site of a tear could be evaluated with AG in 30% (9 of 30); US and CTA showed the site correctly in every patient in which the tear could be diagnosed. CONCLUSION: Ultrasound and CTA were equally accurate in diagnosing and evaluating the size and site of rotator-cuff tears. Double-contrast AG was less accurate in the diagnosis of tears and the size and site of tears clearly could be assessed worse.

Proteoglycan depletion and size reduction in lesions of early grade chondromalacia of the patella.

OBJECTIVE: To determine the content and molecular size of proteoglycans (PGs) in patellar chondromalacia (CM) and control cartilages as a first step in investigating the role of matrix alterations in the pathogenesis of this disease. METHODS: Chondromalacia tissue from 10 patients was removed with a surgical knife. Using identical techniques, apparently healthy cartilage of the same site was obtained from 10 age matched cadavers (mean age 31 years in both groups). Additional pathological cartilage was collected from 67 patients with grades II-IV CM (classified according to Outerbridge) using a motorised shaver under arthroscopic control. The shaved cartilage chips were collected with a dense net from the irrigation fluid of the shaver. The content of tissue PGs was determined by Safranin O precipitation or uronic acid content, and the molecular size by mobility on agarose gel electrophoresis. RESULTS: The mean PG content of the CM tissue samples with a knife was dramatically reduced, being only 15% of that in controls. The cartilage chips collected from shaving operations of grades II, III, and IV CM showed a decreasing PG content: 9%, 5%, and 1% of controls, respectively. Electrophoretic analysis of PGs extracted with guanidium chloride from the shaved tissue samples suggested a significantly reduced size of aggrecans in the mild (grade II) lesions. CONCLUSION: These data show that there is already a dramatic and progressive depletion of PGs in CM grade II lesions. This explains the softening of cartilage, a typical finding in the arthroscopic examination of CM. The PG size reduction observed in grade II implicates proteolytic attack as a factor in the pathogenesis of CM.

Indentation instrument for the measurement of cartilage stiffness under arthroscopic control.

Changes in the biomechanical properties of articular cartilage are one of the first signs of the tissue degeneration. We have developed a small size indentation instrument for the quantification of cartilage stiffness under arthroscopic control. During measurement, the indenter imposes a constant deformation on the cartilage and the maximal indenter force, by which the cartilage resists the deformation, is used as a measure for cartilage stiffness. The instrument has been tested in laboratory conditions with elastomer and cadaver knee joint cartilage samples. A linear relationship was found between indenter force and elastomer stiffness (r = 0.990, n = 14) as well as between indenter force and cartilage shear modulus obtained by a reference device (r = 0.879, n = 22). Also, the correlation between two repeated measurements at the measurement sites, used to evaluate the reproducibility, was linear (r = 0.953, n = 16). Quantitative detection of cartilage stiffness is possible with the instrument.

Decreased torque and electromyographic activity in the extensor thigh muscles in chondromalacia patellae.

The alterations in thigh muscle properties of chondromalacia patellae patients during isometric and dynamic endurance tests were studied using a variokinetic knee testing system linked to surface EMG. A total of 41 patients (chondromalacia group) with arthroscopically certified chondromalacia of the patella were studied. The control group consisted of 31 healthy adult volunteers with no history of knee pain or trauma. Peak torque values were 21% (p < 0.01) and force output values 25% (p < 0.05) lower on the symptomatic side of the chondromalacia group than in the control group. The decrease in the ratio between integrated EMG (IEMG) and measured force were found in all parts of the quadriceps femoris muscle in patients with chondromalacia of the patella in isometric extension. No change in the normalized IEMG levels of the thigh muscles were found between chondromalacia patients and controls in dynamic endurance test. The severity of the chondromalacia of the patella did not affect the level of electromyographic activation in thigh muscles. The ratio of normalized EMG levels of vastus medialis and vastus lateralis did not differ between the groups. The present study showed that chondromalacia patellae patients have reduced force and electromyographic activation levels of quadriceps femoris muscle. Especially, the explosive strength of the quadriceps femoris muscle is reduced.

Lateral release in chondromalacia patellae using clinical, radiologic, electromyographic, and muscle force testing evaluation.

Lateral release (division of the lateral retinaculum of the patella) is a common operative procedure to improve alignment of the patella in patients with chondromalacia patellae. We investigated the effects of lateral release using clinical follow-up and studied the changes in the radiologic measurements of the patellar alignment and electromyographic function of the stabilizing muscles of the knee, as well as using muscle-force tests of the thigh. The study included 75 patients. Diagnostic arthroscopy was done for all patients. In 42 patients with obvious incongruency of the patellofemoral joint observed at arthroscopy, open division of the lateral patellar retinaculum was performed in addition to arthroscopy. Four years after surgery, the results showed that although division of the lateral retinaculum of the patella reduced lateral patellar tilting and lateral patellar displacement, the postoperative physical capacity of the patients was not improved. Lateral release did not impair the electrical activity of thigh muscles. The Lysholm scores of the lateral release group and the control group were equal after four years.

Treatment of a central fracture-dislocation of the hip using external fixation with iliofemoral distraction.

Three patients were treated with external fixation with iliofemoral distraction as an alternative treatment of comminuted central fracture-dislocations of the hip. The patients were mobilized on the first postoperative day and discharged from the hospital an average of 10 days postaccident. The frame was left in place for 6 weeks while the traction was maintained. Full weight bearing was started 3 months after the injury. A full range of motion in the injured hip was achieved at 4 months postoperation. No signs of avascular bone necrosis were seen during follow-up for up to 2 years. The clinical results of the described method were good, and it can be used as an alternative method, especially when open reduction is contraindicated or complicated.

Radiological evaluation of the acromioclavicular joint.

X-ray measurement of the acromioclavicular (AC) joint may cause difficulties because of different projections and the lack of a reproducible measurement. In order to find the ideal measurement to estimate the state of the AC joint, 28 healthy adult volunteers were X-rayed. The least vulnerable measurement for errors in projection was the distance between the coracoid process and the upper part of the clavicle. The effect of stress was evaluated; the range of normal AC joint laxity was determined as 3 mm.