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Articular Cartilage, Bone Bruising, and Chondrosurgery
See also The Degenerate Knee: Arthritis, Long-term Consequences of ACL Injuries, Bearing-Surface Replacement (including Unicompartmental Arthroplasty), Total Knee Replacement/Arthroplasty (TKR/TKA).
For a brief overview of knee anatomy, physiology, and biomechanics, please click here.
Clinical Sports Medicine Update: Autologous Chondrocyte Implantation Postoperative Care and Rehabilitation --
Science and Practice, Karen Hambly et al., American Journal of Sports Medicine, Baltimore, Maryland; June 2006, Volume 34, pages 1020-1038. Comments: This article gives an excellent overview of the rehabilitation options, therapeutic modalities, and exercises available after articular-cartilage repair via ACI (Autologous Chondrocyte Implantation) grafting.
For deeply penetrating insight into the fascinating world of leading-edge MRI diagnostic techniques for detection of articular-cartilage injuries and conditions, see the April 2006 article Magnetic Resonance Imaging of Articular Cartilage -- Trauma, Degeneration, and Repair, by Potter et al., in the Knee-Injury Diagnostics Subsection. For insight into the uselessness of X-rays in ascertaining mild articular-cartilage damage (e.g. as present in chondromalacia), please see the January 2006 article Radiographs Are Not Useful in Detecting Arthroscopically Confirmed Mild Chondral Damage, by Wright et al., in the Knee-Injury Diagnostics Subsection. Arthroscopic Fixation of Osteochondritis Dissecans of the Knee Clinical, Magnetic Resonance Imaging, and Arthroscopic Follow-up, Arturo Makino, The American Journal of Sports Medicine, Baltimore; October 2005, Vol 33, p. 1499-1504. Comments: Osteochondritis dissecans, a separation (delamination) of the articular-cartilage layer from the underlying bone, is troubling in that can bring degeneration and eventual osteoarthritis in the long term. These Argentinian authors found that using a titantium screw to anchor the loose portion brings viable results. One concern that arises with this approach is that even though the screw is countersunk, loss of thickness of the articular cartilage in the area could eventually result in mechanical abrasion (by the screw head) of the mating articular cartilage surface (i.e. on the other bone in the articulation). Also of concern is the fact that the area represented by the screw's presence translates into a reduction (albeit a small one) of load-bearing surface area. Even though the Herbert screw can be removed later on, the space it occupied can, at best, fill with biomechanically suboptimal fibrocartilage (instead of the high-quality hyaline articular cartilage that normally defines a bone's uninjured load-bearing surface). For insight into the inappropriateness of thermal shrinkage in the context of dealing with articular-cartilage damage defects, see the October 2005 article Monopolar Radiofrequency Treatment of Partial-Thickness Cartilage Defects in the Sheep Knee Joint Leads to Extended Cartilage Injury, by Kääb et al., in the Thermal Shrinkage and Other Faded Hopes Subsection. Functional Outcome of Knee Articular Cartilage Repair in Adolescent Athletes, Kai Mithöfer et al., The American Journal of Sports Medicine, Baltimore; August 2005, Vol 33, p. 1147-1153. Comments: This study looked at adolescent athletes with full-thickness articular-cartilage damage (arising from various causes: osteochondritis dissecans, sports injuries, and in a few cases accompanied by ACL tearing and meniscal damage). The people in this study were treated with autologous chondrocyte transplantation (ACI, also known by the brand names Genzyme/Carticel). The surgery entails a three-step process: firstly, harvesting a small sample of the patient's own articular cartilage cells, and secondly, using these cells growing more articular cartilage from these cell in a laboratory setting, and thirdly, implanting these grown cells (chondrocytes) into the patient. Results were excellent at the mean 47 months post-implantation. Hopefully there will be long-term follow-up, since it would be interesting to follow these patients as they progress through life. Ideally, the patients would be followed up annually for the rest of their lives. For a comparison of accelerated versus delayed ACL rehabilitation, and also for insight into to the effects of ACL-injury history on articular cartilage (as ascertained via biochemical means), see the March 2005 article Rehabilitation After Anterior Cruciate Ligament Reconstruction -- A Prospective, Randomized, Double-Blind Comparison of Programs Administered Over 2 Different Time Intervals, by Beynnon et al., in the Physiotherapy, Rehabilitation, and Post-Operative Aspects Pertaining to Ligament Surgeries Subsection. Autologous Chondrocyte Implantation Compared with Microfracture in the Knee: A Randomized Trial
, Gunnar Knutsen et al., Journal of Bone and Joint Surgery, American Edition; March 2004, Volume 86, pages 455-464. Comments: This study found very little difference, at two-year follow-up, between patients who underwent autologous chondrocyte implantation (ACI) and those who simply underwent microfracture. Please be sure to read the commentary by Scott Rodeo, as it identifies a number of important points that must be borne in mind here.
For insight into the location and occurrence of bone bruising commensurate with cruciate-ligament (PCL and/or ACL) tearing, and also for insight into the use of MRI imaging for detection of such articular-cartilage damage, see the October 2004 article Incidence and Location of Bone Bruises After Acute Posterior Cruciate Ligament Injury, by Mair et al., in the Knee-Injury Diagnostics Subsection. Biomechanical and topographic considerations for autologous osteochondral grafting in the knee, Christopher S. Ahmad, The American Journal of Sports Medicine, Baltimore; Mar/Apr 2001, Vol 29/2, p. 201. Comments: This article discusses the complexities behind articular cartilage, and offers insight into reasons why restoring damaged bone-covering cartilage is such a challenge. Radiographic joint space narrowing and histologic changes in a rabbit meniscectomy model of early knee osteoarthrosis, Karola Messner, The American Journal of Sports Medicine, Baltimore; Mar/Apr 2001, Vol 29/2, p. 151. Comments: This article describes the deterioration of articular cartilage observed after removal of rabbit meniscus. The worrisome consequences of meniscal loss are apparent even in short-lived caged rabbits. Clinical outcome of isolated subcortical trabecular fractures (bone bruise) detected by magnetic resonance imaging in knees, Rick W. Wright, The American Journal of Sports Medicine, Baltimore; Sep/Oct 2000, Vol 28/5, p. 663. Comments: This article describes clinical findings of subcortical trabecular bone-damage (bone-bruising) in the knee. (Note that the correlation between such damage and long-term articular-cartilage degeneration has now been solidified.) Comparison of knee joint cartilage thickness in triathletes and physically inactive volunteers based on magnetic resonance imaging and three-dimensional analysis, Roland Muehlbauer, The American Journal of Sports Medicine, Baltimore; Jul/Aug 2000, Vol 28/4, p. 541. Comments: Muehlbauer et al. found that being a triathlete does not have a significant effect on the knee's articular-cartilage thickness. Two- to 9-year outcome after autologous chondrocyte transplantation of the knee, Lars Peterson et al., Clinical Orthopaedics and Related Research, Lippincoot Williams and Wilkins, Baltimore; May 2000, Vol 374, p.212-234. Comments: This Swedish study shows that autologous chondrocyte transplantation/implantation (ACT/ACI) brings good results in the medium term. (This article is provided as a PDF document. Adobe Acrobat Reader can be freely downloaded for all operating systems, including Microsoft Windows and all flavours of Unix/Linux, here. The effect of a geographic lateral bone bruise on knee inflammation after acute anterior cruciate ligament rupture, Darren L. Johnson, The American Journal of Sports Medicine, Baltimore; Mar/Apr 2000, Vol 28/2, p. 152. Comments: This article describes the close correlation between ACL-injury history and subsequent deterioration of articular cartilage. Occult Osteochondral Lesions After Anterior Cruciate Ligament Rupture: Six-Year Magnetic Resonance Imaging Follow-up Study, Kenneth J. Faber, The American Journal of Sports Medicine, Baltimore; Jul/Aug 1999, Vol 27/4, p. 489. Comments: This study followed 23 patients who had acute ACL injuries, underwent MRIs within a few days of the injury, and then had ACL reconstruction. Said patients were brought back six years later for a follow-up MRI. Of these people, 65% had persistent marrow-signal changes. Faber et al. concluded that the initial injury resulted in irreversible changes in the knee. Although the ability of ACL reconstruction to help forestall premature osteoarthritis (as caused by articular-cartilage damage incurred due to the bone-bruising of the initial injury) remains to be fully quantified and is thus still the subject of debate, it is abundantly clear that the consequences of repeated giving-way episodes manifest themselves as permanent damage to bearing surfaces. Articular Cartilage. Part I: Tissue Design and Chondrocyte-Matrix Interactions (An Instructional Course Lecture: The American Academy of Orthopaedic Surgeons)
, J.A. Buckwalter, MD and H.J. Mankin, MD, The American Journal of Sports Medicine, Baltimore; April 1997, Vol 79, p. 600-611. Comments: This article delves into the topic of how the different cells in articular cartilage and the underlying microtrabecular bone interact. This will especially be of interest to those who are familiar with the complex interrelationships between musculoskeletal biomechanics and cell biology.
Articular Cartilage. Part II: Degeneration and Osteoarthrosis, Repair, Regeneration, and Transplantation (An Instructional Course Lecture: The American Academy of Orthopaedic Surgeons) , J.A. Buckwalter, MD and H.J. Mankin, MD, The American Journal of Sports Medicine, Baltimore; April 1997, Vol 79, p. 612-632. This article, which follows from Part I, delves into articular-cartilage deterioration, repair methods, chondrocyte cuturing, and surgical transplantation.
Note: A deep archive of articles and abstracts from Cincinnati Sports Medicine (CSM) Centre, including many landmark studies in the realm of knee biomechanics and trend-setting articles in the fields of ACL reconstruction and meniscal repair, can be found in directly on the CSM Publications Website. The article-publication dates range from 1980 to present. (Note that some of the newer articles are also present directly in this Knee Library.) On the CSM site, full-text articles are given as scanned-to-PDF files. Microsoft Windows users should, due to file-size considerations, download these by right-clicking and choosing "Save Target As". (The files must then be viewed using Adobe/Xerox Acrobat Reader, which is freely available for all computing platforms here.) Some articles on the CSM site are available only as abstracts; however, full-text printed copies may be obtained by contacting Sue Barber-Westin at sbwestin(at)csmref.org. Click here to return to the Main Entrance Page of the Knee Library.
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