Adverse effects on rabbit anterior cruciate ligament after knee immobilization: changes in permeability of horseradish peroxidase

Changes in the permeability of horseradish peroxidase (HRP) and the histology of the rabbit anterior cruciate ligament (ACL) caused by knee immobilization were studied. The knees of adult rabbits were immobilized for 2-8 weeks by a long leg cast with the knee flexed at 120 degrees, and some joints were allowed to be remobilized for 4 weeks after 6 or 8 weeks' immobilization. After 1 ml of HRP was injected into the knee joint and allowed to permeate into the ACL, the degree of permeation at the mid-portion of the ACL between femur and tibia was visualized with diaminobenzidine tetrahydrochloride. The ACL was examined histologically by light and transmission electron microscopy. Although the HRP permeated into almost the entire area of the transverse section of the non-immobilized normal ACL, as the period of immobilization increased, the extent of permeation gradually decreased. The decrease was significant from week 4 to week 6 and from week 6 to week 8. Degenerative change with necrosis of cells at the central area of the ACL was noted in the 6-week immobilization group, and the 8-week period of immobilization increased the extent of this degeneration. Although the permeation recovered in both the 6-week and 8-week immobilization groups 4 weeks after remobilization, there were fewer cells with a normal morphology in the central area in the 8-week immobilization group than in the control. These results suggest that long-term immobilization adversely affects the ACL.

Magnitude of skin vasomotor reflex represents the intensity of nociception under general anesthesia

Because nociceptive stimuli induce the skin vasomotor reflex (SVmR), the assessment of the SVmR would be a useful indicator to represent nociception. We examined 39 adult patients for the relationship between the magnitude of the SVmR and the intensity of nociceptive stimulus that induced the SVmR. Under oxygen-nitrous oxide (50%) and sevoflurane anesthesia, the SVmR was induced by an electrical impulse to the ulnar nerve and detected by a laser Doppler flowmeter. Study 1: under the end-tidal concentrations of sevoflurane at 1.2% (n = 10), 1.7% (n = 9) or 2.2% (n = 10), the SVmR was tested by a 2-s, 50-Hz tetanic electrical impulse with a current intensity changing (40, 50 or 60 mA) in a randomized order. Study 2: under the end-tidal concentration of sevoflurane at 1.7% (n = 10), the SVmR testing was performed with a 50-mA, 50-Hz tetanic electrical impulse with the current duration changing (2, 3 or 4 s) in a randomized order. The studies demonstrated significant correlations of (1) the current intensity which induces the skin vasomotor reflex (SVmR) vs. the magnitude of the SVmR under the three different anesthesia depths, (2) the anesthesia depth vs. the magnitude of the SVmR (inverse proportion) under the same current intensity and (3) the duration of electrostimulation vs. the magnitude of the SVmR. Thus, the SVmR could be helpful for the objective assessment of nociception and anti-nociceptive effects in individual cases.

Plasma transforming growth factor-beta 1 concentrations in patients with chronic viral hepatitis

Transforming growth factor (TGF)-beta 1 is an important cytokine involved in the pathobiology of tissue fibrosis through its stimulation of the production of, and inhibition of the degradation of, extracellular matrix proteins. We examined the clinical usefulness of plasma TGF-beta 1 concentration as a marker of fibrogenesis in patients with chronic viral hepatitis. Thirty-five patients, 11 with minimal chronic hepatitis, 14 with mild chronic hepatitis and 10 with moderate chronic hepatitis and 20 healthy subjects were studied. Transforming growth factor-beta 1 concentrations in platelet-poor plasma were measured with a TGF-beta 1 enzyme-linked immunosorbent assay system kit after acid-ethanol extraction. Plasma TGF-beta 1 levels were significantly elevated in patients with mild and moderate chronic hepatitis, but not in those with minimal chronic hepatitis, compared with the levels in the controls. Plasma TGF-beta 1 levels were increased in parallel with the histological degree of necroinflammation and of liver fibrosis. Plasma TGF-beta 1 levels were positively correlated with blood levels of procollagen type III N-peptide, and 7S fragment and central triple-helix of type IV collagen. These results suggest that plasma TGF-beta 1 level is a useful marker in assessing the situation of liver active fibrogenesis in patients with chronic viral hepatitis.

Assessing the level of regional blockade under general anesthesia using the skin vasomotor reflex test

We investigated whether skin vasomotor reflex (SVmR) testing can be used to assess the sensory blockade level under light general anesthesia. In 15 patients scheduled for abdominal gynecological surgery, the SVmR was tested under inhaled isoflurane or sevoflurane (0.5%-0.6%) with nitrous oxide (50%). Seven minutes after the epidural injection (5-10 mL of 2% lidocaine), a tetanic electrical stimulus (20 mA, 2 s) was applied to the skin and repeated sequentially from the L3 dermatome in the cephalad direction. Changes in the laser Doppler skin blood flow on the index finger tip were assessed for the SVmR. If there was a positive response, SVmR testing was discontinued. The relationship between the uppermost dermatome of the negative SVmR response and the intraoperative effectiveness of the epidural block was determined. In 11 patients, we confirmed a clear boundary of skin dermatome by the SVmR test. The uppermost dermatome of the negative SVmR response at higher than the T7 level was necessary to maintain the combined epidural and light general anesthesia for the transabdominal gynecological surgery (P = 0.002). We conclude that SVmR testing is useful in estimating the blockade level of regional anesthesia under light general anesthesia.

IMPLICATIONS

Considering "preemptive analgesia," a complete sensory blockade should be established before a skin incision. In 11 of 15 patients under epidural/ general anesthesia, we confirmed a clear dermatome boundary using the skin vasomotor reflex test. This test could be an indicator for estimating the sensory blockade level of patients under general anesthesia.

Post-prandial serum hyaluronan concentration in patients with chronic liver disease

Serum hyaluronan measurement is an option for diagnosing cirrhosis and assessing liver fibrosis, but it is of little use in the diagnosis of chronic hepatitis and compensated liver cirrhosis. It is generally known that intake of food results in elevation of the serum hyaluronan concentration. This work was designed to determine whether a change in the serum hyaluronan concentration after eating might reflect the hepatic sinusoidal endothelial cell impairment in chronic liver diseases. The chronological measurement of serum hyaluronan concentration after eating was performed after an overnight fast in 31 patients with chronic hepatitis, 31 cirrhotic patients, and 8 healthy subjects. The hyaluronan concentration in the loading test increased with the severity of the liver disease in the patients with chronic hepatitis, being significantly higher in the patients with moderate or a higher grade of necroinflammation than in those with a minimal grade, and also significantly higher in patients with stage 3 fibrosis than in those with stage 2 or less. The elevation of the concentration after eating in patients with liver cirrhosis was marked and the range did not overlap with that in patients with chronic hepatitis. Even in 14 patients with compensated liver cirrhosis whose hyaluronan concentration pre-prandially was less than 200 ng/ml, the range of the post-prandial peak concentration did not overlap with that in the chronic hepatitis patients. These results suggest that the evaluation of post-prandial serum hyaluronan concentration is potentially useful for assessing the grading of necroinflammation and staging of fibrosis in patients with chronic hepatitis, as well as for diagnosing compensated liver cirrhosis.

Quantitative evaluation of nutritional pathways for the posterior cruciate ligament and the lateral collateral ligament in rabbits

The cruciate ligament of the knee receives its nutrition from a direct vascular supply and by permeation of nutrients from the synovial fluid. The contributions of these two routes as nutritional pathways are not known in detail. In this study, we injected [3H]methyl glucose as a tracer intravenously or directly into the knee of rabbits. Tracer concentrations in plasma, synovial fluid, the posterior cruciate ligament (PCL), and the lateral collateral ligament (LCL) were analysed by a pharmacokinetic compartment model. The contribution of [3H]methyl glucose permeation from the synovial fluid during steady state was calculated at 44.3% in the PCL and at 39.0% in the LCL. Although these results indicated that more than half the nutrition for both ligaments is provided by its vascular supply, synovial fluid permeation is also an important transport route for small molecules for the PCL and the LCL, which is an extra-articular structure.

Antinociceptive effects of neurotropin in a rat model of painful peripheral mononeuropathy

A non-protein extract isolated from the inflamed skin of rabbits inoculated with vaccinia virus (Neurotropin, NTP), has been clinically used in Japan for the treatment of chronic painful conditions such as low back pain, osteoarthritis, postherpetic neuralgia, subacute myelo-opticoneuropathy, and so on. Recent studies have shown its efficacy on patients with complex regional pain syndrome (CRPS). The chronic constriction injury (CCI) model described by Bennett and Xie has been thought to show similar painful conditions to those seen in CRPS patients. Thus, the antinociceptive effects of NTP were tested in CCI model. In rats with mechanical hyperalgesia 2 weeks after nerve injury, i.p. injection of NTP (100 Neurotropin Unit, NU/kg) produced an analgesic effect that lasted for at least 50 min. An analgesic effect lasting up to 30 min. was observed in rats with heat hyperalgesia 2 weeks after nerve injury. Seven daily i.p. injections (50 NU/kg) of NTP commencing 1 week after surgery produced an early recovery from heat hyperalgesia. Prior studies suggest that NTP produces analgesia by activation of a descending pain inhibitory system. Thus, our findings suggest the possibility that the dysfunction of the descending pain inhibitory system could be related to the hyperalgesia in the nerve injury model, and perhaps also in people who suffer from painful peripheral neuropathies.

MR evaluation of human anterior cruciate ligament autograft on oblique axial imaging

PURPOSE

The purpose was to observe the changing MR appearance of stable anterior cruciate ligament (ACL) grafts on oblique axial images.

METHOD

Fifty-five knees in 44 patients were studied with MRI 1-54 months after arthroscopic ACL reconstruction with double-looped autogenous semitendinosus and gracilis tendons. Knees with poor stability were excluded from this study. Examinations were performed at 0.2 T with SE proton density and T2-weighted sagittal and oblique axial images.

RESULTS

High signal intensity areas covered the grafts 1-3 months after surgery. The high signal subsequently extended into the intertendinous bundles. The entire graft gradually became a low signal intensity bundle again after 12 months. Grafts were classified by their appearance on the oblique axial images.

CONCLUSION

We conclude that high signal intensity can be seen within stable ACL grafts.

Lipoma arborescens in bilateral knee joints

We report a case of lipoma arborescens of both knee joints. In the face of chronic joint hydrops, it is important to consider lipoma arborescens in the differential diagnosis and to try to make early diagnosis, using magnetic resonance imaging or another means of examination.

Skin vasomotor reflex predicts circulatory responses to laryngoscopy and intubation

BACKGROUND

An evaluation of autonomic reactivity may help to predict circulatory responses to intubation. The relation between the magnitude of the skin vasomotor reflex (SVmR) immediately before laryngoscopy and the circulatory responses to intubation was examined.

METHODS

Forty-four adult patients (classified as American Society of Anesthesiologists physical status I or II) were studied. General anesthesia was induced with fentanyl and thiamylal and maintained with nitrous oxide and sevoflurane. The SVmR was evoked by an electrostimulus to the ulnar nerve, and decreases in skin blood flow were detected using a laser-Doppler flowmeter. In study 1, two groups of patients were studied. In the monitored group (n = 14), laryngoscopy was performed when the SVmR amplitude had decreased to less than 0.1. In the control group (n = 15), intubation was performed regardless of changes in the SVmR amplitude. In study 2, after induction, the end-tidal concentration of sevoflurane was maintained at 1 MAC (n = 9) or 1.3 MAC (n = 6) for 5 min. The SVmR was tested by changing the electric intensity.

RESULTS

In study 1, the blood pressure and heart rate of the control group increased significantly (P < 0.01) after laryngoscopy. The blood pressure of the monitored group did not increase. The SVmR amplitude and the systolic blood pressure changes showed a significant linear correlation (P < 0.001). In study 2, the relation between the electric intensity and the SVmR amplitude showed a weak but significant correlation (P < 0.01) in the 1 MAC group.

CONCLUSION

The evaluation of the SVmR provides useful information for determining the optimal anesthetic depth for laryngoscopy and intubation in individual patients.

Molecular weight of hyaluronate in the serum of patients with chronic liver disease

Hyaluronate in tissue and lymph is known to be heterogenous and to show a wide range of molecular weights (10(4) to 10(7) Da). Serum hyaluronate concentrations are increased under various pathophysiological conditions such as liver disease, post-gastrectomy, and after the ingestion of food. To clarify whether the chromatographic patterns of hyaluronate in serum from patients with chronic liver disease are different under these conditions, we subjected sera to chromatography using a Sephacryl S 400 HR column. The chromatograms revealed that the hyaluronate in serum was eluted as a single peak at the position corresponding to the molecular weight of blue dextran, the molecular weight being more than 2 x 10(6) Da. The patterns of the chromatogram were similar among the patients with liver disease and the healthy subject although the heights of the peaks were different. Ingestion of food and a history of gastrectomy for gastric cancer did not influence the elution patterns of serum hyaluronate. These results indicate that hyaluronate in serum has molecular weight of more than 2 x 10(6) Da, and that its elution patterns are not influenced by pathophysiological factors, such as the severity of liver disease, or history of gastrectomy or by food intake in patients with chronic liver disease.

Skin vasomotor reflex as an objective indicator to assess the level of regional anesthesia

We examined whether the absence of a skin vasomotor reflex (SVmR), which represents a sympathetic vasoconstrictive response to various stimuli, is an objective indicator of a somatosensory blockade. Skin blood flow was measured by using a laser Doppler flowmeter on the index finger tip. The somatosensory blockade level was determined in 15 patients under subarachnoid anesthesia. A cold stimulus, an ice cube applied to the skin, was repeated sequentially at each dermatome from L3 cephalad. The uppermost dermatome with negative response (the SVmR cold level) was determined, and the SVmR pain level was determined similarly using an electrical impulse (20-mA, 50-Hz, 0.25-ms square wave). The SVmR cold level and the SVmR pain level showed significant correlation with the conventionally assessed cold level (r = 0.83) and the pinprick level (r = 0.96). We conclude that the SVmR is useful to objectively estimate the level of somatosensory block induced by regional anesthesia.

IMPLICATIONS

We evaluated the absence of decrease in skin blood flow after various stimuli as an indicator of somatosensory blockade. In patients under subarachnoid anesthesia, the uppermost level with negative response showed significant correlation with the conventionally assessed blockade level. This method is useful for objective assessment of regional anesthesia level.

Topical delivery of keloid therapeutic drug, tranilast, by combined use of oleic acid and propylene glycol as a penetration enhancer: evaluation by skin microdialysis in rats

Topical delivery of tranilast (N-(3,4-dimethoxycinnamoyl)anthranic acid), an inhibitor of collagen synthesis and a therapeutic drug for keloid and hypertrophic scar, was examined, in rats, with oleic acid alone or a combination of oleic acid and propylene glycol as penetration enhancer. Evaluation was by measurement of the concentration of tranilast in plasma and in the dialysate from skin microdialysis. When tranilast at a dose of 1.5 mg was applied topically as an ethanol solution containing 5% polyvinylpyrrolidone on a dorsal skin surface (2.25 cm2), the maximum concentration of tranilast in skin dialysate was approximately 2 microM. When 10 or 20% oleic acid was added to the same ethanol solution the maximum concentration of tranilast in the dialysate increased to 10-20 microM, and this value was further increased to 60 microM by the addition of a combination of oleic acid (10 or 20%) and propylene glycol (10%) to the solution. With the combination of oleic acid and propylene glycol the area under the plot of the concentration of tranilast in skin dialysate against time between 0 and 4 h (AUC0-4) was more than 400-fold that after intravenous administration. The transdermal bioavailability of tranilast as assessed by the AUC0-4 of tranilast in plasma, was 0.2% of the dose applied in the ethanol solution, 3-5% of that applied in the ethanol solution containing oleic acid, and 14-16% of that applied in the ethanol solution containing both oleic acid and propylene glycol. These results suggest that the topical delivery of tranilast with an absorption enhancer such as a mixture of oleic acid and propylene glycol might be a more effective medication than oral administration of tranilast for the treatment of keloid and hypertrophic scar.

Skin vasomotor reflex induced by laryngoscopy: comparison of the McCoy and Macintosh blades

We studied 22 female patients (ASA I or II) to investigate if laryngoscopy and intubation induced the skin vasomotor reflex (SVmR), and to compare the effects of the McCoy and Macintosh blades on the SVmR. Anaesthesia was induced with fentanyl, midazolam, vecuronium and nitrous oxide. In 11 patients, the vocal cords were seen for 3 s with the McCoy blade. Two minutes later, laryngoscopy was performed with the Macintosh blade and the trachea was intubated. In the other 11 patients, the first and second laryngoscopies, respectively, were performed with the Macintosh and McCoy blades. Laryngoscopy alone and intubation with laryngoscopy significantly reduced skin blood flow in the ring finger of all patients (P < 0.01), indicating that both procedures provoked the SVmR. The magnitude of the SVmR and haemodynamic changes did not differ significantly between the two groups.

Histological and biomechanical observations of the rabbit patellar tendon after removal of its central one-third

Using 35 Japanese white rabbits, a study was made of tissue regeneration and the mechanical properties of the patellar tendon after removal of its central one-third. After removal of the central one-third of the patellar tendon on one side, in experiment 1 the strength of the entire patellar tendon including the regenerated tissue was compared with that of the patellar tendon on the opposite side with the central one-third removed at the time of killing, and in experiment 2 the strength of only the regenerated tissue was compared with that of the patellar tendon on the opposite side with two-thirds of the medial and lateral sides removed at the time of death. In experiment 1, the maximum load showed no significant difference between the operated side and the control. In one half of the cases, the strength of the operated side including the regenerated tissue was weak, suggesting weakening of the patellar tendon on the residual bilateral sides. In experiment 2, the maximum load of the regenerated tissue was significantly lower than that of the control, the former being 25% of the latter even at 6 months. Histologically, the characteristics of the cells and collagen fibers gradually approached those of normal tissue, but the crimp pattern of the collagen fibers and fibrils was evidently smaller than that of the control. These results indicate that regenerated tissue was still mechanically weak and immature at 6 months.

Influence of distal nerve segment volume on nerve regeneration in silicone tubes

The influence of a volume of a distal nerve segment upon nerve regeneration in an 8-mm gap created within a silicone tube was examined. The rats were randomly divided into four groups. Each group had 5 mm, 1 mm, or a half volume of 1-mm nerve segment (a nerve piece of 1 mm transected longitudinally) inserted into the distal end of a silicone tube of 11 mm. The empty group without a nerve segment was used as control. Diameters of regenerated cylindrical structure between the nerve ends in the silicone tube were measured under an operation microscope and myelinated axon diameter, myelinated axon density, myelin sheath width, and ratio of myelinated axon area to total cross sectional area were measured using the transverse sections at the midpoint of the silicone tube at 6 weeks after surgery. Although there was a significant difference in all of those parameters between the control group and any of the remaining three groups, no significant difference was found between any pair of these three groups. The results of this study indicated that the degree of nerve regeneration does not correlate with the volume of a distal nerve segment and even a very small piece can play an important role in supporting regenerating nerve beyond a definitive gap.

Tissue inhibitor of metalloproteinase-1 in the liver of patients with chronic liver disease

BACKGROUND/AIMS

Tissue inhibitor of metalloproteinase (TIMP)-1 is an important regulator of matrix metalloproteinase activity. To clarify the changes in TIMP-1 in diseased livers, we measured TIMP-1 concentrations in liver tissue samples from patients with chronic liver disease. The relationship between serum and liver levels of TIMP-1 was also examined in some patients.

METHODS

The subjects were 68 patients who underwent liver biopsy. The liver TIMP-1 concentration was measured using an enzyme immunoassay after the extraction of TIMP-1 with 2 M guanidine.

RESULTS

As compared with the controls (n=10), the liver TIMP-1 level was increased 2.2-fold in the 24 chronic active hepatitis 2A patients, 2.9-fold in the 10 chronic active hepatitis 2B patients and 4.1-fold in the six liver cirrhosis patients, but no significant increase was observed among the 18 chronic persistent hepatitis patients. The liver TIMP-1 levels were closely correlated with the histological degrees of periportal necrosis, portal inflammation, and liver fibrosis. When the localization of TIMP-1 was examined immunohistochemically, TIMP-1 was stained mainly in hepatocytes, and the intensity was stronger in the livers of chronic active hepatitis and liver cirrhosis patients than in those of the chronic persistent hepatitis patients. The serum TIMP-1 and liver TIMP-1 levels were significantly correlated, indicating that serum TIMP-1 could reflect the change of liver TIMP-1 in patients with chronic liver disease.

CONCLUSION

Liver TIMP-1 concentration increases with progression of the liver disease, when the degradation of extracellular matrix proteins is decreased, resulting in the development of liver fibrosis.

Treatment of keloid and hypertrophic scars by iontophoretic transdermal delivery of tranilast

The feasibility of iontophoretic transdermal delivery of tranilast (N-(3,4-dimethoxycinnamoyl) anthranilic acid) for the treatment of keloid and hypertrophic scars was evaluated in hairless rats and humans. A drug electrode containing tranilast 1.5 ml (8 mg/ml in ethanol/water (8/2, v/v) mixture) was placed on the dorsal skin surface of anaesthetised rats or the affected parts of patients, and connected to the negative pole; an electric current (0.5-4 mA for rats, 2 mA for people) was pulsed through at one minute intervals. Tranilast was effectively delivered transdermally iontophoretically into the restricted skin tissues of hairless rats and the affected parts of four patients with hypertrophic scars with no skin damage. In four other patients tranilast given iontophoretically for a period of 30 minutes a week reduced the patients' complaints of pain and itching after only one or two treatments although there were some variations among patients. These results indicate that the transdermal iontophoretic delivery of tranilast is a useful treatment for keloid and hypertrophic scars, particularly for relieving pain and itching, and is more beneficial than tranilast given orally.

[An anesthesia machine malfunction due to dew condensation produced by abnormally high humidity in the electronically-controlled panel]

We present a case of anesthesia machine (NAR-KOMED 2CTM; N2C) malfunction caused by dew condensation. N2C is electronically controlled by an alarm-panel using the remote display. Abnormally high humidity in the operating room made dew condensation in the alarm-panel resulting in an electronic short circuit. Of great importance may be the damp proof improvement on medical equipment including anesthesia machines which have electronic circuits.

[A case of advanced colon cancer with marked response to combination chemotherapy with 5-FU, low dose CDDP, and leucovorin]

We encountered an elderly patient with advanced colon cancer who responded marked by to combination chemotherapy with 5-fluorouracil (5-FU), low-dose cisplatin (CDDP), and leucovorin (LV). The 86-year-old man was admitted for advanced transverse colon cancer with liver and lung metastasis. Combination chemotherapy with 5-FU, low dose CDDP, and LV was given for a total of 12 weeks. After this chemotherapeutic regimen, diagnostic CT scan revealed the metastatic lesions had disappeared, and a pathological analysis of primary tumor confirmed that the patient had achieved a complete remission (CR). During chemotherapy, there was no severe side effect, apart from mild nausea (WHO: Grade 1). The patient is presently enjoying a good general condition and has been rehabilitated for discharge.

Changes in the permeability and histologic findings of rabbit menisci after immobilization

The knees of mature rabbits were immobilized for 2 to 8 weeks by a long leg cast to examine adverse effects on the meniscus. Some joints were remobilized for 1 to 4 weeks after an immobilization period of either 6 or 8 weeks. Horseradish peroxidase was injected into knee joints, and the degree of permeation into the meniscus was visualized with diaminobenzidine tetrahydrochloride. Menisci were examined histologically by light and transmission electron microscopic study. Injected horseradish peroxidase permeated all areas of the meniscus in nonimmobilized joints. However, permeability of horseradish peroxidase gradually decreased with increasing time of immobilization and was restricted to the superficial layer of the meniscus in the 8-week immobilization group. Degenerative changes in the deep layers of the meniscus were noted in the 6-week immobilization group: 8 weeks of immobilization induced additional degenerative changes. Although permeability of horseradish peroxidase gradually recovered with remobilization, the degenerative changes remained in the deep meniscal layer in the 8-week immobilization group, even after 4 weeks of remobilization. These results clearly show that long-term immobilization of the knee joint causes adverse changes in the meniscus.

Rotational acetabular osteotomies: a rabbit model

We investigated the morphological changes in the articular cartilage after rotational acetabular osteotomy in 16 adolescent rabbits. Radiological and histological studies were conducted at 12 and 24 weeks postoperatively. The radiological evaluations at 12 and 24 weeks showed significantly increased femoral head coverage. No cases of osteonecrosis of the acetabulum or femoral head nor narrowing of the joint space was observed. The histology of the articular cartilage at 12 weeks postoperatively showed cloning and hypercellularity of the chondrocytes in the medial portion of the acetabular roof, indicating remodelling due to the increased weight-bearing stress caused by the osteotomy. The histology at 24 weeks postoperatively showed less cloning of the chondrocytes, indicating that the remodelling process in the articular cartilage induced by this procedure was almost complete at 24 weeks. Degeneration of the articular cartilage was not observed within 24 weeks of the operation.