Exposure Of Subchondral Bone Research Articles

Rectangular Recession Trochleoplasty for Treatment of Patellar Luxation in Dogs and Cats

SummaryTrochleoplasty is a fundamental component of surgical treatment for patients with inadequate trochlear depth associated with patellar luxation. Traditional methods of trochleoplasty include trochlear resection, chondroplasty and wedge recession trochleoplasty. Each technique has its benefits and limitations. Rectangular recession trochleoplasty (RRT) is a new technique that builds upon the strengths of its predecessors while minimizing their limitations. Rectangular recession utilizes a rectangular osteochondral autograft that is harvested from the trochlear groove and replaced into its recipient bed. Unlike wedge recession, the autograft surfaces are compressed and buttressed within the recipient bed. resulting in secure implantation of the autograft. Rectangular recession achieves maximal preservation of hyaline articular cartilage while minimizing exposure of abrasive subchondral bone. Rectangular recession can be performed on dogs and cats as small as 3 kg and has been clinically effective in treating over 100 cases of patellar luxation.Trochleoplasty is an important surgical procedure for treatment of patellar luxation in the dog and cat. The objective of any trochleoplasty technique is to achieve adequate trochlear depth and width while optimizing preservation of hyaline articular cartilage. Rectangular recession trochleoplasty (RRT) is a new technique that achieves adequate trochlear width and depth utilizing a securely “press-fit” osteochondral autograft that achieves maximal preservation of hyaline articular cartilage.

Magnetic resonance imaging of articular cartilage in the knee. An evaluation with use of fast-spin-echo imaging.

The purpose of this study was to demonstrate that specialized magnetic resonance imaging provides an accurate assessment of lesions of the articular cartilage of the knee. Arthroscopy was used as the comparative standard. Eighty-eight patients who had an average age of thirty-eight years were evaluated with magnetic resonance imaging and subsequent arthroscopy because of a suspected meniscal or ligamentous injury. The magnetic resonance imaging was performed with a specialized sequence in the sagittal, coronal, and axial planes. Seven articular surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial plateaus) were graded prospectively on the magnetic resonance images by two independent readers with use of the 5-point classification system of Outerbridge, which was also used at arthroscopy. Six hundred and sixteen articular surfaces were assessed, and 248 lesions were identified at arthroscopy. Eighty-two surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep ulceration, fibrillation, or a flap without exposure of subchondral bone; and thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0 and 1 were regarded as disease-negative status and grades 2, 3, and 4 were regarded as disease-positive status. When the grades that had been assigned by reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent (144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the detection of a chondral lesion. Interobserver variability was minimum, as indicated by a weighted kappa statistic of 0.93 (almost perfect agreement). With use of this readily available modified magnetic resonance imaging sequence, it is possible to assess all articular surfaces of the knee accurately and thereby identify lesions that are amenable to arthroscopic treatment.

Use of allografts after failed treatment of rupture of the anterior cruciate ligament.

A prospective study was done of the use of allogeneic tissue to reconstruct the anterior cruciate ligament in knees in which an intra-articular or an extra-articular operation had failed. Sixty-six consecutive patients (sixty-six knees) had such an operation with use of bone-patellar ligament-bone allografts; all but one returned for follow-up evaluation twenty-three to seventy-eight months (mean, forty-two months) after the operation. A total of 235 previous operations had been performed in these sixty-six knees, including eighty-one procedures for rupture of the anterior cruciate ligament. The results of the allograft procedure were evaluated with a subjective and objective system that rated twenty factors. The anterior-posterior displacement was substantially improved in most of the patients. According to data derived from arthrometric studies and pivot-shift tests of the fifty-seven patients who were so evaluated and in whom the condition was unilateral, 53 per cent (thirty) of the reconstructed ligaments were determined to be functional; 21 per cent (twelve ligaments), partially functional; and 26 per cent (fifteen ligaments), a failure. When we calculated the rate of failure by including ten failures that had occurred within two years after the operation with the fifteen that occurred in patients who had been followed for at least two years, the over-all rate of failure was 33 per cent (twenty-five of seventy-five operations). There was significant improvement in the subjective ratings of functional limitations and symptoms (p < 0.01) and in the over-all rating score (p < 0.0001). However, there was a significant difference between the scores of the patients in whom the surfaces of the articular cartilage had appeared normal at the index operation and those of the patients in whom there had been noteworthy fissuring and fragmentation or exposure of subchondral bone. After the program of rehabilitation, which included immediate motion of the knee, a range of motion of 0 to 135 degrees was restored in all but five knees, four of which lacked only 5 degrees of this extent of flexion or extension. The results demonstrate that bone-patellar ligament-bone allografts may be used when proper autogenous tissues are not available and that symptoms and abnormal displacement were reduced in most of our patients.

Osteochondrosis associated with copper deficiency in young farmed red deer and wapiti x red deer hybrids

Osteochondrosis is reported in association with copper deficiency in young red deer and wapiti X red deer hybrids on eight deer farms throughout New Zealand. On two farms, more than 30% of fawns were affected. Affected animals were lame, often had one or more swollen joints, and in some cases had an abnormal "bunny-hopping" gait or "cow-hocked" stance. Lesions were most common in the carpal, tarsal, stifle and hip joints, and were usually bilateral. Defects in articular cartilage ranged from loose flaps to complete separation with exposure of subchondral bone and the presence of cartilage fragments within the joint space. In advanced cases, the joints had features of degenerative arthropathy. Bilateral epiphyseolysis of the femoral head was observed in some severely lame deer. All deer with osteochondrosis had low serum and/or liver copper concentrations.

Osteochondrosis in association with copper deficiency in farmed deer calves

Abstract Osteochondrosis has been recognised in association with copper deficiency in young farmed red deer and wapiti X red deer hybrids on several deer farms throughout New Zealand. On some properties more than 30% of fawns were affected. Affected animals were lame, often had one or more swollen joints and in some cases had an abnormal “bunny-hopping” gait or “COW hocked” stance. Lesions were most common in the carpal, tarsal, stifle and hip joints and were usually bilateral. Defects in articular cartilage ranged from loose flaps to complete separation with exposure of subchondral bone and the presence of loose bodies within the joint space. In advanced cases the joints had features of degenerative arthropathy. Bilaterial epiphyseolysis of the femoral head was observed in some severely lame deer.

High tibial osteotomy and ligament reconstruction in varus angulated, anterior cruciate ligament-deficient knees. A two- to seven-year follow-up study.

We assessed short-term treatment results of younger patients with varus malalignment and chronic anterior cruciate ligament deficiency. Forty-one patients (mean, 32 years; range, 16 to 47) underwent a high tibial osteotomy. Because of giving way symptoms, 14 also had a lateral iliotibial band extraarticular procedure at the time of the osteotomy and 16 had an intraarticular anterior cruciate ligament allograft reconstruction after the osteotomy. All returned for followup (mean, 58 months; range, 23 to 86), which included KT-1000 arthrometer testing and evaluation by our knee rating system. Statistically significant (P < 0.05) improvements were found in the mean overall rating scores for pain, swelling, and giving way. Preoperatively, 30 (73%) had pain with activities of daily living or with any sports activity; 11 (27%) could perform only light sports activities without pain. At followup, 32 patients (78%) had no pain with activities of daily living or light sports. Ten of 15 patients with advanced medial tibiofemoral arthrosis (subchondral bone exposure) had significant improvements in symptoms. Patient satisfaction was high: 88% stated they would undergo the procedure again and 78% felt their knee condition was improved. Patients who had the allograft reconstruction had significantly lower (P < 0.05) anterior-posterior displacements at followup than those who had the extraarticular procedure. We concluded that osteotomy should be performed early in the disease process for younger athletes who experience symptoms with activity. It may be unrealistic, however, to expect continuation of sports beyond light recreational, given the joint arthrosis that is usually present and the high in vivo joint loadings with athletes. Anterior cruciate ligament reconstruction should be considered when giving way previously occurred and the patient plans to resume athletics. However, patients with advanced arthrosis can avoid anterior cruciate ligament surgery by reducing athletic activities.

The Pathology of Canine Hip Dysplasia

Although the complete pathogenesis of cartilage damage in canine hip dysplasia has not been completely worked out, it appears that joint laxity with resultant excessive stresses upon articular cartilage is the initiating factor. Grossly, this damage is characterized by cartilage thinning with potential exposure of subchondral bone, osteophyte formation, and pannus formation. Microscopically, there is a marked variation in chondrocyte cellularity, with focal regions of hypocellularity and chondrocyte clusters and synovial lining cell hyperplasia and hypertrophy as well as a decrease in proteoglycan content. This latter change has been substantiated biomechanically. Ultrastructural studies indicate that there is extensive alteration of collagen organization within the cartilage.

Patellar cartilage lesions: in vitro detection and staging with MR imaging and pathologic correlation.

Fourteen freshly disarticulated knee specimens were studied to assess the usefulness of magnetic resonance (MR) imaging in the detection and correct staging of patellar chondral lesions. Axial and sagittal images were obtained; T1-weighted spin-echo sequences were found satisfactory for defining cartilage morphology. Specimens were sectioned and examined grossly for cartilage changes such as softening, blistering, fibrillation, fissuring, and frank subchondral bone exposure. In a side-by-side comparison, all lesions classified grossly in the Shahriaree system as stage II or higher showed MR changes. Stage I changes could not be identified in disarticulated specimens. Stage III lesions showed cartilage irregularity (ulceration) or a loss of the normal, sharply defined margin between coapted cartilage, which represented "crabmeat" fibrillation. Stage IV lesions showed ulceration to bone, sometimes with subchondral bone changes. In this in vitro, preliminary study, MR imaging was found to be an accurate means for detecting and staging moderate and advanced patellar cartilage lesions.

Chondromalacia patellae: assessment with MR imaging.

Magnetic resonance (MR) images of the posterior patellar hyaline articular cartilage were obtained in 23 subjects to determine if MR imaging could accurately demonstrate the patellar cartilage. Arthroscopy was used as the standard of reference. Three subjects were asymptomatic volunteers. In the remaining 20 who had patellofemoral pain, arthroscopy was performed before MR imaging in seven and afterward in 12; one did not undergo arthroscopy. MR imaging showed focal areas of swelling of the patellar cartilage, focal hypointensity, surface irregularity, areas of thinning, and areas of cartilage loss with exposure of subchondral bone. The surgical findings agreed with those from MR images in all seven patients who underwent arthroscopy before MR imaging and in ten of the 12 who underwent surgery afterward. MR imaging is an accurate means of examining the posterior patellar cartilage and should be considered as an alternative to diagnostic arthroscopy when chondromalacia patellae is suspected.

The lumbar facet arthrosis syndrome. Clinical presentation and articular surface changes.

We describe a lumbar facet syndrome in which disabling symptoms are associated with normal or near-normal plain radiographs. Local spinal fusion relieved symptoms in 12 patients; the excised facet joint surfaces showed some of the histological changes seen in chondromalacia patellae and in osteoarthritis of other large joints. The most frequent change was focal full-thickness cartilage necrosis or loss of cartilage with exposure of subchondral bone, but osteophyte formation was remarkably absent in all specimens. We suggest that there are both clinical and histological similarities between the facet arthrosis syndrome and chondromalacia patellae. Facet arthrosis may be a relatively important cause of intractable back pain in young and middle-aged adults.

Long-term results of deep defects in articular cartilage

Core defects produced in the medial femoral condyle of the rabbit were studied by scanning electron microscopy and light microscopy over a period of 2 years. In some cases the defect was filled by hyaline articular cartilage with a fairly smooth surface, but in others the tissue was markedly fibrillated and resembled fibrous tissue and fibrocartilage. Appearances suggesting disintegration of the newly formed cartilage were seen in some cases. It would appear that a continuation of this process can lead to the exposure of subchondral bone. In one instance no repair tissue or new cartilage could be identified but the surrounding old cartilage had formed a shelf over the defect. The cartilage surrounding the defect was either normal or showed superficial fibrillation, and/or flow formation, and/or fissures.