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Louis C Almekinders - One of the best experts on this subject based on the ideXlab platform.

  • Strain patterns in the Patellar tendon and the implications for Patellar tendinopathy
    Knee Surgery Sports Traumatology Arthroscopy, 2002
    Co-Authors: Louis C Almekinders, Jurrien H. Vellema, Paul S. Weinhold
    Abstract:

    This study investigated the strain pattern in human Patellar tendon in an area of the tendon where changes commonly associated with Patellar Tendinitis are found. Eight fresh frozen human knees were instrumented with strain gauges on both the anterior and posterior side of the proximal Patellar tendon. Both static and dynamic measurements were carried out in a range from 0° to 60° of flexion. We found uniform tensile strain in the tendon with the knee in full extension. However, as the knee was brought into flexion, the tensile strain increased on the anterior side but decreased on the posterior side in the central, proximal location of the tendon. The posterior side of the proximal Patellar tendon is most commonly affected in Patellar tendinopathy. This study indicates that this area of the tendon may not subjected to the highest tensile loads in the functional flexion range. It is possible that stress shielding is more important etiological factor in insertional tendinopathy as opposed to repetitive tensile loads.

  • Patellar Tendinitis the significance of magnetic resonance imaging findings
    American Journal of Sports Medicine, 1999
    Co-Authors: Marc Shalaby, Louis C Almekinders
    Abstract:

    We evaluated the significance of magnetic resonance imaging findings in patients with Patellar Tendinitis. Midline sagittal magnetic resonance images were taken of 12 knees from 10 patients and of 17 knees from 15 age- and activity-matched subjects who underwent imaging for reasons other than Patellar Tendinitis. Of the 12 magnetic resonance imaging scans of knees with clinical Patellar Tendinitis, 3 (25%) exhibited no defect and only 7 (58%) had unequivocal intratendinous lesions. Among the 17 scans of subjects without clinical Patellar Tendinitis, 5 (34%) showed no defect and 4 (24%) had unequivocal intratendinous lesions. Proximal tendon width was significantly larger for the Tendinitis patient group (5.0 1.7 mm versus 3.9 1.0 mm), although considerable overlap was present. All subjects with unequivocal intratendinous signal changes had a significantly longer nonarticular inferior Patellar pole and were significantly older (38.1 years versus 26.8 years). Only Blazina stage III lesions were associated w...

  • Patellar Tendinitis the significance of magnetic resonance imaging findings
    American Journal of Sports Medicine, 1999
    Co-Authors: Marc Shalaby, Louis C Almekinders
    Abstract:

    We evaluated the significance of magnetic resonance imaging findings in patients with Patellar Tendinitis. Midline sagittal magnetic resonance images were taken of 12 knees from 10 patients and of 17 knees from 15 age- and activity-matched subjects who underwent imaging for reasons other than Patellar Tendinitis. Of the 12 magnetic resonance imaging scans of knees with clinical Patellar Tendinitis, 3 (25%) exhibited no defect and only 7 (58%) had unequivocal intratendinous lesions. Among the 17 scans of subjects without clinical Patellar Tendinitis, 5 (34%) showed no defect and 4 (24%) had unequivocal intratendinous lesions. Proximal tendon width was significantly larger for the Tendinitis patient group (5.0 +/- 1.7 mm versus 3.9 +/- 1.0 mm), although considerable overlap was present. All subjects with unequivocal intratendinous signal changes had a significantly longer nonarticular inferior Patellar pole and were significantly older (38.1 years versus 26.8 years). Only Blazina stage III lesions were associated with abnormal findings on magnetic resonance imaging. As a whole, the sensitivity and specificity of magnetic resonance imaging was 75% and 29%, respectively. In younger patients with relatively mild symptoms, magnetic resonance imaging did not show significant changes; in older, active patients changes may be present in asymptomatic knees.

Christopher C. Kaeding - One of the best experts on this subject based on the ideXlab platform.

  • recalcitrant Patellar Tendinitis magnetic resonance imaging histologic evaluation and surgical treatment
    American Journal of Sports Medicine, 1997
    Co-Authors: James E Popp, Joseph S Yu, Christopher C. Kaeding
    Abstract:

    Magnetic resonance imaging findings and the results of surgical treatment and histologic evaluation of 11 knees in 9 athletes with recalcitrant Patellar Tendinitis are reported. All of the athletes had no improvement with traditional nonoperative treatment and all had ab normal magnetic resonance imaging findings consis tent with chronic Patellar Tendinitis. Surgical exploration and debridement were performed on the 11 knees by the same surgeon. With a minimum followup of 1 year, 7 of the 11 knees had excellent results, 3 had good results, and 1 had a poor result. Histologic evaluation of the debrided tissue was consistent with "angiofibro blastic tendinosis," which correlated with the abnormal preoperative magnetic resonance imaging findings in the proximal third of the infraPatellar tendon. This study correlated histologic findings with magnetic resonance imaging findings and shows that in selected patients excellent results can be achieved with surgical treat ment of recalcitrant Patellar Tendinitis or...

  • correlation of mr imaging and pathologic findings in athletes undergoing surgery for chronic Patellar Tendinitis
    American Journal of Roentgenology, 1995
    Co-Authors: Joseph S Yu, Christopher C. Kaeding, J E Popp, J Lucas
    Abstract:

    OBJECTIVE: Jumper's knee, or chronic Patellar Tendinitis, can be a source of considerable pain in athletes. The changes that occur with shearing of the tendinous fibers from repeated microtrauma can progress to significant degeneration and increase the risk of tendon rupture. In order to better understand this phenomenon, a correlative study relating the MR imaging and pathologic findings was performed. SUBJECTS AND METHODS: Nine high-performance athletes 18-22 years old (mean age, 20 years) underwent operation of 11 knees for long-standing jumper's knee. The average period of symptoms was 3 years (range, 2 to 6 years). MR knee examinations were performed before surgery in all athletes. The symptoms, MR findings, and pathological findings were correlated. RESULTS: There was focal thickening in the proximal one third of the Patellar tendon (range, 9-16 mm; mean, 12 mm) in all 11 knees, involving the medial portion of the tendon in 10 and the center in one. On proton-density-weighted MR images, all knees demonstrated a focus of abnormal signal intensity in the proximal one third of the Patellar tendon. On T2-weighted MR images, 10 knees demonstrated abnormal signal intensity; eight were isointense to that seen on proton-density-weighted images, and two were relatively hyperintense. Ten tendons demonstrated a poorly defined posterior margin. Pathologically, the areas of abnormal signal intensity corresponded to tissue containing tenocyte hyperplasia, prominent angiogenesis with endothelial hyperplasia, loss of longitudinal collagenous architecture, and microtears with collagen fiber separation. Hyaline degeneration was present in specimens from every patient. CONCLUSION: In athletes with chronic Patellar Tendinitis, areas of abnormal signal intensity on MR imaging corresponded to degenerative pathologic changes consistent with angiofibroblastic tendinosis. In nearly all patients, the tendon thickening occurred eccentrically. Disproportionate medial tendon thickening may be related to unequal tensile forces across the knee joint, resulting in greater stress on the medial portion of the extensor mechanism of the knee.

  • correlation of mr imaging and pathologic findings in athletes undergoing surgery for chronic Patellar Tendinitis
    American Journal of Roentgenology, 1995
    Co-Authors: J E Popp, Christopher C. Kaeding, J Lucas
    Abstract:

    Jumper's knee, or chronic Patellar Tendinitis, can be a source of considerable pain in athletes. The changes that occur with shearing of the tendinous fibers from repeated microtrauma can progress to significant degeneration and increase the risk of tendon rupture. In order to better understand this phenomenon, a correlative study relating the MR imaging and pathologic findings was performed.Nine high-performance athletes 18-22 years old (mean age, 20 years) underwent operation of 11 knees for long-standing jumper's knee. The average period of symptoms was 3 years (range, 2 to 6 years). MR knee examinations were performed before surgery in all athletes. The symptoms, MR findings, and pathological findings were correlated.There was focal thickening in the proximal one third of the Patellar tendon (range, 9-16 mm; mean, 12 mm) in all 11 knees, involving the medial portion of the tendon in 10 and the center in one. On proton-density-weighted MR images, all knees demonstrated a focus of abnormal signal intens...

J Lucas - One of the best experts on this subject based on the ideXlab platform.

  • correlation of mr imaging and pathologic findings in athletes undergoing surgery for chronic Patellar Tendinitis
    American Journal of Roentgenology, 1995
    Co-Authors: Joseph S Yu, Christopher C. Kaeding, J E Popp, J Lucas
    Abstract:

    OBJECTIVE: Jumper's knee, or chronic Patellar Tendinitis, can be a source of considerable pain in athletes. The changes that occur with shearing of the tendinous fibers from repeated microtrauma can progress to significant degeneration and increase the risk of tendon rupture. In order to better understand this phenomenon, a correlative study relating the MR imaging and pathologic findings was performed. SUBJECTS AND METHODS: Nine high-performance athletes 18-22 years old (mean age, 20 years) underwent operation of 11 knees for long-standing jumper's knee. The average period of symptoms was 3 years (range, 2 to 6 years). MR knee examinations were performed before surgery in all athletes. The symptoms, MR findings, and pathological findings were correlated. RESULTS: There was focal thickening in the proximal one third of the Patellar tendon (range, 9-16 mm; mean, 12 mm) in all 11 knees, involving the medial portion of the tendon in 10 and the center in one. On proton-density-weighted MR images, all knees demonstrated a focus of abnormal signal intensity in the proximal one third of the Patellar tendon. On T2-weighted MR images, 10 knees demonstrated abnormal signal intensity; eight were isointense to that seen on proton-density-weighted images, and two were relatively hyperintense. Ten tendons demonstrated a poorly defined posterior margin. Pathologically, the areas of abnormal signal intensity corresponded to tissue containing tenocyte hyperplasia, prominent angiogenesis with endothelial hyperplasia, loss of longitudinal collagenous architecture, and microtears with collagen fiber separation. Hyaline degeneration was present in specimens from every patient. CONCLUSION: In athletes with chronic Patellar Tendinitis, areas of abnormal signal intensity on MR imaging corresponded to degenerative pathologic changes consistent with angiofibroblastic tendinosis. In nearly all patients, the tendon thickening occurred eccentrically. Disproportionate medial tendon thickening may be related to unequal tensile forces across the knee joint, resulting in greater stress on the medial portion of the extensor mechanism of the knee.

  • correlation of mr imaging and pathologic findings in athletes undergoing surgery for chronic Patellar Tendinitis
    American Journal of Roentgenology, 1995
    Co-Authors: J E Popp, Christopher C. Kaeding, J Lucas
    Abstract:

    Jumper's knee, or chronic Patellar Tendinitis, can be a source of considerable pain in athletes. The changes that occur with shearing of the tendinous fibers from repeated microtrauma can progress to significant degeneration and increase the risk of tendon rupture. In order to better understand this phenomenon, a correlative study relating the MR imaging and pathologic findings was performed.Nine high-performance athletes 18-22 years old (mean age, 20 years) underwent operation of 11 knees for long-standing jumper's knee. The average period of symptoms was 3 years (range, 2 to 6 years). MR knee examinations were performed before surgery in all athletes. The symptoms, MR findings, and pathological findings were correlated.There was focal thickening in the proximal one third of the Patellar tendon (range, 9-16 mm; mean, 12 mm) in all 11 knees, involving the medial portion of the tendon in 10 and the center in one. On proton-density-weighted MR images, all knees demonstrated a focus of abnormal signal intens...

Dirk Cambier - One of the best experts on this subject based on the ideXlab platform.

  • intrinsic risk factors for the development of Patellar Tendinitis in an athletic population a two year prospective study
    American Journal of Sports Medicine, 2001
    Co-Authors: Erik Witvrouw, Lieven Danneels, Roeland Lysens, Johan Bellemans, Dirk Cambier
    Abstract:

    Retrospective studies have suggested various factors that might cause a disposition to develop Patellar Tendinitis, but no prospective data exist to determine any relationships. The purpose of this study was to determine the intrinsic risk factors for the development of Patellar Tendinitis in an athletic population. Before the study, 138 male and female students of physical education were evaluated for anthropometric variables, leg alignment characteristics, and muscle tightness and strength parameters. During the 2-year study, 19 of the 138 students developed Patellar Tendinitis. In all cases the diagnosis was confirmed by the presence of a hypoechogenic nodular lesion in the proximal region of the Patellar tendon. Univariate and stepwise discriminant function analyses were performed comparing the various measurements. These analyses revealed that the only significant determining factor was muscular flexibility, with the Patellar Tendinitis patients being less flexible in the quadriceps and hamstring mus...

  • intrinsic risk factors for the development of Patellar Tendinitis in an athletic population a two year prospective study
    American Journal of Sports Medicine, 2001
    Co-Authors: Erik Witvrouw, Lieven Danneels, Roeland Lysens, Johan Bellemans, Dirk Cambier
    Abstract:

    Retrospective studies have suggested various factors that might cause a disposition to develop Patellar Tendinitis, but no prospective data exist to determine any relationships. The purpose of this study was to determine the intrinsic risk factors for the development of Patellar Tendinitis in an athletic population. Before the study, 138 male and female students of physical education were evaluated for anthropometric variables, leg alignment characteristics, and muscle tightness and strength parameters. During the 2-year study, 19 of the 138 students developed Patellar Tendinitis. In all cases the diagnosis was confirmed by the presence of a hypoechogenic nodular lesion in the proximal region of the Patellar tendon. Univariate and stepwise discriminant function analyses were performed comparing the various measurements. These analyses revealed that the only significant determining factor was muscular flexibility, with the Patellar Tendinitis patients being less flexible in the quadriceps and hamstring muscles (P < 0.05). The results of this study demonstrate that lower flexibility of the quadriceps and hamstring muscles may contribute to the development of Patellar Tendinitis in an athletic population. Therefore, the prevention of this condition in athletes should be focused on screening for and treating poor quadriceps and hamstring muscle flexibility.

Christopher D Harner - One of the best experts on this subject based on the ideXlab platform.