Patella tendon

PURPOSE: To define the contributions of the of the medial patellofemoral ligament (MPFL) and medial quadriceps tendon femoral ligament (MQTFL) to lateral patellar translation as the knee moves through a 90° arc of motion. METHODS: Six pairs of bilateral cadaveric knee specimens (12 knees) were dissected and potted in perfect lateral position using fluoroscopy. An eye screw was placed in the midpoint on the lateral aspect of the patella. Each knee underwent testing in 4 conditions after sequential sectioning: intact, lateral retinacular release, randomized MQTFL or MPFL sectioning, and complete proximal medial patellar restraint (PMPR) sectioning...

OBJECTIVE: Elucidating the role of structural mechanisms in the knee can improve joint surgeries, rehabilitation, and understanding of biped locomotion. Identification of key features, however, is challenging due to limitations in simulation and in-vivo studies. In particular the coupling of the patello-femoral and tibio-femoral joints with ligaments and its impact on joint mechanics and movement is not understood. We investigate this coupling experimentally through the design and testing of a robotic sagittal plane model...

BACKGROUND: Cruciate ligament (CL) and patellar tendon (PT) are important elements of the knee joint, uniting femur, patella and tibia into a single functional unit. So far, knowledge on the developmental mechanism of CL, PT and patella falls far behind other skeletal tissues. RESULTS: Here, employing various lineage tracing strategies we investigate the cellular sources and dynamics that drive CL, PT and patella formation during mouse embryonic development. We show that Gdf5 and Gli1 are generally expressed in the same cell population that only contributes to CL, but not PT or patella development...

Patellar tendon rupture is an uncommon but disabling lesion. It usually occurs in men younger than 40 years, through direct or indirect trauma. Obtaining satisfactory results with treatment of chronic injuries and re-ruptures in which the patella retracts owing to quadriceps contraction is a challenge. This is of major concern especially in cases in which the patella cannot be positioned in its anatomic position when distal traction is performed. In these cases, V-Y stretching of the quadriceps can be performed in an attempt to perform reconstruction in 1 stage...

Patella baja is a challenging pathologic condition that causes pain and functional restrictions and can even lead to premature osteoarthritis-even more so in cases of patella infera or cases associated with degeneration of the patellar tendon in which simple conservative treatment frequently is not resolutive. Several surgical options have been described for symptomatic patella baja: excision of the lower third of the patella, lengthening of the patellar tendon, reconstruction of the patellar tendon with allograft, and proximalization of the tibial tubercle...

Cartilage lesions of the knee pose a difficult challenge for orthopaedic surgeons. Osteochondral allograft transplantation is an option in the setting of large chondral or osseous defects, or after failure of other treatment options1-3 . The use of allograft offers the benefit of utilizing both viable hyaline cartilage and bone4 . Fresh allografts are usually transplanted into the femoral condyle, although they can also be used in the patella, tibial plateau, or femoral trochlea1 . Research has shown that patients who undergo this procedure for the treatment of focal and diffuse chondral defects have favorable outcomes and satisfaction scores1 ...

Cartilage lesions of the knee pose a difficult challenge for orthopaedic surgeons. Osteochondral allograft transplantation is an option in the setting of large chondral or osseous defects, or after failure of other treatment options1-3 . The use of allograft offers the benefit of utilizing both viable hyaline cartilage and bone4 . Fresh allografts are usually transplanted into the femoral condyle, although they can also be used in the patella, tibial plateau, or femoral trochlea1 . Research has shown that patients who undergo this procedure for the treatment of focal and diffuse chondral defects have favorable outcomes and satisfaction scores1 ...

BACKGROUND: Patellar tendon rupture is an infrequent and debilitating condition, which if left untreated, is complicated by quadriceps contracture and patella alta. This results in reduced function of the knee extensor mechanism including extension lag, reduced range of motion (ROM), chronic knee pain, and frequent falls. Early primary repair has good results in most cases and is performed by opposing and suturing the tendon ends. However, when there is a delay between rupture and repair or in case of a re-rupture, primary repair techniques may not work due to retraction of the extensor mechanism...

Patella baja in total knee arthroplasty can result in impingement, pain, and decreased range of motion. Etiology can range from previous knee surgeries such as anterior cruciate ligament reconstruction, retrograde femoral nail, infrapatellar fat pad resection, and previous total knee arthroplasty. Diagnosis can be confirmed by one of a number of measurements of patellar height including Insall-Salvati and Blackburne-Peel ratios. It is important to differentiate between true patella baja and pseudopatella baja by patellar height ratio...

The extensor mechanism provides active knee joint extension and stability of the patellofemoral joint. Rupture of the quadriceps tendon, although uncommon, is therefore associated with impairment in knee joint stability and, thus, requires surgical repair. Although various techniques provide excellent clinical outcomes for acute rupture, treatment of chronic rupture remains clinically challenging. We describe our modified technique for quadriceps tendon repair using a semitendinosus tendon autograft, with suturing of the quadriceps tendon stump to the patella via transosseous sutures, wherein the use of allograft and anchors is avoided...

Recurrent patellar instability is a common problem and often leads to a tear of the medial patellofemoral ligament. Multiple reconstruction techniques for the medial patellofemoral ligament (MPFL) exist. This Technical Note presents a technique for performing MPFL reconstruction using Achilles tendon allograft with a bone block. The advantages of this technique include (1) bone-to-bone healing in femoral tunnel; (2) docking the bone block in the femoral tunnel obviates the knee for calculating graft and tunnel length; (3) fixing the femoral side before the patellar side allows graft tensioning under direct visualization and avoids over-constraint; (4) the fanned portion of the Achilles tendon allows broad-based MPFL footprint coverage on the medial patellar ridge; and (5) it avoids the need for bone tunnel drilling in the patella, reducing the risk to penetration of the drill holes into the articular cartilage surface as well as the risk for patellar fracture...

INTRODUCTION: The purpose of this study was to determine the changes in the shape and volume of the infrapatellar fat pad (IPFP) associated with knee flexion angle in young healthy individuals. METHODS: Young, healthy individuals without a history of knee injuries participated in this cross-sectional study. Behavior of the IPFP was quantified using three-dimensional (3D) models of the IPFP, patella, patellar tendon, femur, and tibia obtained from MRI taken at 0° and 30° flexion...

We perform prospective study to evaluate the isokinetic performance of quadriceps before and 1 year after medial patella-femoral ligament (MPFL) reconstruction with the adductor magnus tendon in the case of recurrent patellar dislocation. The present study is the first to describe the isokinetic function of the quadriceps of the involved and uninvolved extremity, in such a wide range. The MPFL is a crucial passive stabilizer of patella and, along with the conditions of the anatomical shape of the femoral-patellar joint and the function of quadriceps, influences the overall patellar stability...

OBJECTIVE: To determine the correlation between patellar tendon-lateral femoral condyle friction syndrome (PLFFS) and the morphological characteristics of the antero-inferior part of the lateral femoral condyle (ALFC) to explore the potential pathogenesis. METHODS: A total of 170 knees of 140 patients with PLFFS (PLFFS group) were retrospectively analyzed using magnetic resonance imaging (MRI) data for a 4-year period from our database. The Insall-Salvati ratio, shape of the ALFC (SALFC, defined as two subtypes: sharp versus blunt), lateral femoral condyle angle (LFCA), lateral trochlear length (LTL), and lateral trochlear height (LTH) were measured on MRI...

Surgical options for patellofemoral (PF) disorders include proximal or distal realignment, cartilage restoration techniques, open or arthroscopic lateral retinacular release, and medial soft-tissue reefing. Skeletal immaturity and donor-site morbidity can be of concern in most reconstructive procedures. The Goldthwait procedure with hemi-patellar transfer and medialization combined with arthroscopic lateral retinacular release results in medialization of the PF contact point in flexion and corrects maltracking to prevent recurrent patellar dislocation...

Anterior cruciate ligament (ACL) reconstruction is considered as a successful orthopaedic procedure that attempts to help patients return to their preinjury level of activity. However, some patients may need to undergo revision surgery, and this potentially may be associated with certain surgery-specific or patient risk factors. Therefore, the purpose of this study was to assess the potential role of (1) demographics, (2) family history, (3) graft choice, (4) sport, and (5) mechanism of injury (contact vs. noncontact) in the risk for needing a revision ACL for improved clinical outcomes...

The greater muscular strength of long-term resistance-trained (LTT) individuals is often attributed to hypertrophy, but the role of other factors, notably maximum voluntary specific tension (ST), muscle architecture, and any differences in joint mechanics (moment arm), have not been documented. The aim of the present study was to examine the musculoskeletal factors that might explain the greater quadriceps strength and size of LTT vs. untrained (UT) individuals. LTT ( n = 16, age 21.6 ± 2.0 yr) had 4.0 ± 0...

OBJECTIVE: Eccentric exercise is commonly used as a form of loading exercise for individuals with patellar tendinopathy. This study investigated the change of mechanical properties and clinical outcomes and their interrelationships after a 12-week single-legged decline-board exercise with and without extracorporeal shockwave therapy (ESWT). DESIGN: Randomized controlled trial. SETTING: Outpatient clinic of a university. PARTICIPANTS: Thirty-four male in-season athletes with patellar tendinopathy for more than 3 months were randomized into exercise and combined groups...

CASE: We present an 18-year-old man with poor alignment of the lower limbs, marked by congenital dislocation of the left patella, with gait impairment, and an associated 20° flexion contracture. Surgical treatment was performed with a single complex procedure with the release of the lateral retinaculum, capsule, and iliotibial tract, followed by a subtraction trochleoplasty, tibial tubercle transfer, elongation of the quadriceps tendon, and anatomical reconstruction of the medial patellofemoral ligament...

Magnesium plays a critical role in athlete health and performance. It is involved in numerous physiological mechanisms that support energy production, immune function, pain modulation, muscle function and bone health. Athletes may be susceptible to magnesium deficiency due to an increased utilization during exercise. Objective: This study reports on the magnesium status of 192 Olympic and Paralympic athletes over the course of eight years. Methods: Athletes on the British Athletics world class performance plan undertook blood testing for Red Cell Magnesium status...