Search results for "Patella"

(i) Comminuted patellar fractures

2006

Summary Purpose of review This article reviews current best practice for the diagnosis and treatment of comminuted patellar fractures. Recent findings Patellar fractures make up about 1% of all fractures. As a rule, fractures of the patella are caused by direct trauma to the knee. A transverse fracture is the most common fracture type. Open reduction and internal fixation is the treatment of choice for the majority of displaced patellar fractures. Treatment must achieve anatomic reduction of the articular surface and reestablish the continuity of the extensor mechanism. Tension-band wiring, interfragmentary screw fixation and a combination of cerclage wiring and screw fixation are the most …

Quasi-Fractional Models of Human Tendons Hereditariness

2018

In this study, the authors, after collecting a series of experimental evidences following a creep and relaxation tendon campaign, propose a non-linear model of the viscoelastic behavior of the tendons. The ligaments investigated are the patellars and the hamstrings. The analytical model proposed by the authors aims to explain the non-linear hereditary behavior of these tissues and proposes an approach with which to develop a hereditary fractional-order non-linear model.

The distribution of cartilage thickness in the knee-joints of old-aged individuals -- measurement by A-mode ultrasound.

1997

Abstract Objective. To provide data on the normal distribution of cartilage thickness in the knee joints of old-aged individuals. Design. The accuracy and reproducibility of cartilage thickness measurements were evaluated with A-mode ultrasound, and the cartilage thickness distribution was examined throughout both knee joints of nine individuals aged between 62 and 94 yr. Background. Data on the variation of cartilage thickness in the joint surfaces are relevant for the design of computer models of diathrodial joints and for surgical and arthroscopic procedures, particularly the calculation of cartilage material properties from indentation tests. Methods. A 12.5 MHz A-mode ultrasound transd…

Kinematics of the patellofemoral joint. Investigations on a computer model with reference to patellar fractures.

1990

Patellofemoral kinematics were studied on a computer model. The articulating point of the patella moves from distal to proximal during flexion, until the quadriceps tendon starts to turn around the femur tendo-femoral gliding. The pattern of patellofemoral movement consists of a gliding and rolling component, the latter at its maximum at the beginning of flexion. The pathway of the instant centers of motion moves from dorsal to ventral during flexion. Stress analysis shows that the contact area is at all times the area of maximum bending stress. The distal part of the patella is the part with mechanical stress at all angles of flexion. The conclusions to be drawn for treatment are that frac…

2021

Vibroarthrography measures joint sounds caused by sliding of the joint surfaces over each other. and can be affected by joint health, load and type of movement. Since both warm-up and muscle fatigue lead to local changes in the knee joint (e.g., temperature increase, lubrication of the joint, muscle activation), these may impact knee joint sounds. Therefore, this study investigates the effects of warm-up and muscle fatiguing exercise on knee joint sounds during an activity of daily living. Seventeen healthy, physically active volunteers (25.7 ± 2 years, 7 males) performed a control and an intervention session with a wash-out phase of one week. The control session consisted of sitting on a c…

Healing of the patellar tendon donor defect created after central-third patellar tendon autograft harvest

1999

Patellar tendon donor defect (PTDD) healing after patellar tendon autograft (PTA), was evaluated in 12 lambs (24 knees), by means of conventional histology, immunohistochemistry and image analysis. The results of this study indicate that the PTDD is replaced by a tissue that does not assume the histological characteristics of a normal patellar tendon. Both the Hoffa fat pad (HFP) and the paratenon play an important role in the healing process, although qualitative and quantitative chronological differences were found, which supports the concept of a “two-time process”. The HFP initiates the repair process, and is the main active proliferative tissue compartment during the first week. Once t…

Simultaneous chronic rupture of quadriceps tendon and contra-lateral patellar tendon in a patient affected by tertiary hyperparatiroidism

2007

Abstract Spontaneous ruptures of the extensor mechanism of the knee are very rare. They tend to increase considerably in patients with metabolic diseases such as chronic renal failure, hyperparathyroidism, diabetes, gout, and systemic lupus erythematosus. The reported case regards a 48-year-old man with chronic, spontaneous and simultaneous quadriceps, and contra-lateral patellar tendon rupture. The patient suffered from chronic renal failure and for the past year from tertiary hyperparathyroidism. Ruptured tendons were repaired and both knee were evaluated monthly for the next 12 months. Good functional recovery was achieved on both knees without relapse. This case emphasizes the importanc…

Biomechanical Bases for Anterior Knee Pain and Patellar Instability

2012

The anterior knee pain syndrome and functional patellar instability in the active young person is one of the most complex knee disorders, with a multiple factor and highly variable pathogenesis, with intermingling mechanical and neurological factors. Probably the neural factor is the cause of the well established symptoms in patients with certain mechanical anomalies and a knee overuse.

Taking the acid test: Mediterranean limpets face up to climate change

2014

Impacts of climate change involve the interactions of multiple stressors on intertidal organisms, but rarely are the impacts of these stressors examined together. Many tests are also conducted in artificial, controlled laboratory conditions, without making use of natural opportunities to test performance of organisms under different environmental stressors. Given its small tidal range, the Mediterranean Sea provides such an opportunity, with a very fine scale environmental gradient and species living very close to each other over the tidal gradient. The vertical distribution of the limpets, Patella rustica and P. caerulea overlap in Palermo, Sicily, but despite this they have different ther…

Muscle‐tendon morphology and function following long‐term exposure to repeated and strenuous mechanical loading

2020

We mapped structural and functional characteristics of muscle‐tendon units in a population exposed to very long‐term routine overloading. Twenty‐eight military academy cadets (age: 21.00 ± 1.1 yrs; height: 176.1 ± 4.8 cm; mass: 73.8 ± 7.0 kg) exposed for over 24 months to repetitive overloading were profiled via ultrasonography with a senior subgroup of them (n = 11; age = 21.4 ± 1.0 yrs; height = 176.5 ± 4.8 cm; mass = 71.4 ± 6.6 kg) also tested while walking and marching on a treadmill. A group of eleven ethnicity‐ and aged‐matched civilians (age = 21.6 ± 0.7 yrs; height = 176.8 ± 4.3 cm; mass = 74.6 ± 5.6 kg) was also profiled and tested. Cadets and civilians exhibited similar morphology…