Vague Posterior Knee Discomfort in a Soccer Player: A Clinical Vignette.

A 24-yr-old male soccer player presented with a 7-yr history of left posterior knee "looseness." Evaluation 7 yrs ago, at the time of initial injury, revealed atraumatic anterior and posterior cruciate ligament sprains. On representation, the patient described the pain as a constant, dull ache, 3/10, but his biggest complaint was this feeling of "instability" and looseness where his knee would "buckle" 3-4 times a week. Physical examination was positive for grade 1 posterior drawer and grade 1 posterior sag signs. Reverse KT-1000 testing showed a 3-mm side-to-side difference. Sonographic evaluation confirmed magnetic resonance imaging findings of posterior cruciate ligament laxity and buckling and a small cystic lesion abutting the posteromedial margin of the distal 1/3 of the posterior cruciate ligament. After a trial of physical therapy, the patient elected to undergo experimental injection of dextrose hyperosmolar solution. This resulted in resolution of the cyst and reverse KT-1000 measurements improved to a side-to-side difference of 1 mm. The patient's subjective feeling of looseness and instability resolved by 7 wks.

Characterizing adolescents with heavy menstrual bleeding and generalized joint hypermobility.

Patients with generalized joint hypermobility (JHM) may experience excessive bruising/bleeding, with heavy menstrual bleeding (HMB) commonly reported. We performed a retrospective review of 30 adolescents seen in a Young Women's Hematology Clinic with both HMB and JHM. We found that (1) a significant delay (mean 36 months, range 5-72) occurred between menarche and referral to specialty care, (2) HMB had moderate to severe impact on school and physical activities in 60% of patients, and (3) most patients (68%) required escalation of their initial therapy. We suggest providers consider JHM as a risk factor for a more complex clinical course.

Hypermobility in individuals with Kabuki syndrome: The effect of growth hormone treatment.

Kabuki syndrome (KS) is a multiple congenital malformation syndrome which has been described across all ethnic groups. Most KS patients possess two genetic subtypes: KMT2D-associated, autosomal-dominant KS type 1 (KS1; OMIM 147920); and KDM6A-associated, X-linked-dominant KS type 2. Generalized joint hypermobility is one feature of KS, but its exact incidence and pattern is not well described in the literature. As part of our prospective study on the metabolic and growth effect of GH treatment, we assessed children from our Dutch Kabuki cohort who were eligible for growth hormone therapy. We assessed severity and pattern of joint hypermobility, both before and after 24 months of growth hormone replacement therapy. The prevalence of hypermobility was 31% in boys and 14% in girls using the Beighton score and 69% in boys and 57% in girls using the Bulbena score. This varies from the general population where girls are more affected. After 2 years of growth hormone treatment, there was a statistically significant decrease in the presence of joint hypermobility to 6% using the Bulbena score and none with respect to the Beighton score. We hypothesized that this result suggests a direct effect of growth hormone on connective tissue in patients with KS.

Long-term therapeutic effects of dextrose prolotherapy in patients with hypermobility of the temporomandibular joint: a single-arm study with 1-4 years' follow up.

The aim was to analyse the short-term and long-term therapeutic efficacy of dextrose prolotherapy for dislocation or subluxation (hypermobility) of the temporomandibular joint (TMJ). Sixty-one patients with symptomatic hypermobility of the TMJ were included in this single-arm prospective study, in which they were each given four sessions of intra-articular and pericapsular injections six weeks apart. Each injection comprised 10% dextrose/mepivacaine solution 3ml. Clinical outcomes including severity of pain on movement according to the numerical rating scale (NRS), maximal interincisal opening, clicking, and frequency of locking were measured before treatment (T1), during treatment (T2) (just before the third session of injections), at the short-term follow-up (T3) (three months after treatment), and at the long-term follow-up (T4) (1-4 years after treatment). Condylar translation and osseous changes of each joint were evaluated at T1 and T4 using tomography. There was significant reduction in all variables by T2 (p<0.001, p<0.001, p=0.006, and p<0.001). The pain scores (p<0.001) and clicking (p<0.001) had decreased significantly by T3. Linear tomograms of each joint at T1 and T4 showed no alteration in the morphology of the bony components of the joint, and at T4, tomographic open views of all joints showed condylar hypertranslation. Dextrose prolotherapy provided significant and sustained reduction of pain and recovery of constitutional symptoms associated with symptomatic hypermobility of the TMJ without changing either the position of the condyle or the morphology of the bony components of the joint.

[THE ROLE OF TRANSFORMING GROWTH FACTOR-B IN IMMUNOPATHOGENESIS OF DISEASES OF CONNECTIVE TISSUE].

The recent studies of molecular physiology of fibrillin and pathophysiology of inherent disorders of structure and function of connective tissue such as dissection and aneurysm of aorta, myxomatously altered cusps and prolapses of mitral valve, syndrome of hyper-mobility of joints, demonstrated that important role in development of these malformations play alterations of transfer of signals by growth factors and matrix cellular interaction. These conditions under manifesting Marfan's syndrome can be a consequence of anomalies of fibrillin-1 which deficiency unbrakes process of activation of transforming growth factor-ß (TGFß). The involvement of TGFß in pathogenesis of Marfan's syndrome permits consider antagonists of angiotensin-transforming enzymes as potential pharmaceuticals in therapy of this disease. The article presents analysis of publications' data related to this problem.

Corneal Cross-Linking for Brittle Cornea Syndrome.

PURPOSE: To describe corneal cross-linking (CXL) as a treatment option for brittle cornea syndrome (BCS). METHODS: Case report. RESULTS: Ethical decision making enabled bilateral sequential transepithelial CXL in an 11-year-old girl with BCS. Postoperative courses were uneventful with a bilateral stromal demarcation line, unchanged corneal transparency, constant endothelial cell density, and stable topography 2 years after intervention. CONCLUSIONS: Modified CXL can safely be performed in patients with BCS. Ethical review may be helpful for interventions deviating from standard practice.

Diffuse neonatal hemangiomatosis in a very low-birthweight infant treated with erythropoietin.

Diffuse neonatal hemangiomatosis (DNH) is a rare condition characterized by the concomitant development of multiple cutaneous infantile hemangiomas (IH) and visceral hemangiomas. Recently, an association between erythropoietin treatment and an increased incidence of infantile hemangioma was noted. A Japanese male infant was born via cesarean section at 27 weeks of gestation. Following the commencement of erythropoietin treatment for anemia of prematurity, he developed multiple cutaneous hemangiomas, high cardiac output heart failure and hepatomegaly. Abdominal imaging indicated comorbidity of diffuse infantile hepatic hemannigomas, resulting in the final diagnosis of DNH. The discontinuation of erythropoietin treatment and long-term therapy with propranolol improved the hepatic lesions and cutaneous hemangiomas. The possibility of multiple organ involvement and the exacerbating effects of erythropoietin treatment should be considered in cases in which multiple cutaneous hemangiomas develop in preterm infants receiving erythropoietin treatment.

Modified dextrose prolotherapy for recurrent temporomandibular joint dislocation.

Conservative interventions with simple procedures and predictable benefits are expected by patients with recurrent dislocation of the temporomandibular joint (TMJ). We have introduced a modified technique of prolotherapy that comprises injection of lignocaine and 50% dextrose at a single site in the posterior periarticular tissues. We studied the effects in 45 younger patients (age range 17-59 years) with non-neurogenic recurrent dislocation of the TMJ, and confirmed the therapeutic effect after more than a year's follow-up. There were appreciable improvements in the number of episodes of dislocation and clicking after the injection. The overall success rate, defined as the absence of any further dislocation or subluxation for more than 6 months, was 41/45 (91%). Of the 41 rehabilitated patients, 26 (63%) required a single injection, 11 (27%) had 2 treatments, and 4 (10%) needed a third injection. All patients tolerated the injections well. The modified dextrose prolotherapy is simple, safe, and cost-effective for the treatment of recurrent dislocation of the TMJ.

Current evidence for effectiveness of interventions for cubital tunnel syndrome, radial tunnel syndrome, instability, or bursitis of the elbow: a systematic review.

OBJECTIVE: To provide an evidence-based overview of the effectiveness of interventions for 4 nontraumatic painful disorders sharing the anatomic region of the elbow: cubital tunnel syndrome, radial tunnel syndrome, elbow instability, and olecranon bursitis. METHODS: The Cochrane Library, PubMed, Embase, PEDro, and CINAHL were searched to identify relevant reviews and randomized clinical trials (RCTs). Two reviewers independently extracted data and assessed the quality of the methodology. A best-evidence synthesis was used to summarize the results. RESULTS: One systematic review and 6 RCTs were included. For the surgical treatment of cubital tunnel syndrome (1 review, 3 RCTs), comparing simple decompression with anterior ulnar nerve transposition, no evidence was found in favor of either one of these. Limited evidence was found in favor of medial epicondylectomy versus anterior transposition and for early postoperative therapy versus immobilization. No evidence was found for the effect of local steroid injection in addition to splinting. No RCTs were found for radial tunnel syndrome. For olecranon bursitis (1 RCT), limited evidence for effectiveness was found for methylprednisolone acetate injection plus naproxen. Concerning elbow instability, including 2 RCTs, one showed that nonsurgical treatment resulted in similar results compared with surgery, whereas the other found limited evidence for the effectiveness in favor of early mobilization versus 3 weeks of immobilization after surgery. DISCUSSION: In this review no, or at best, limited evidence was found for the effectiveness of nonsurgical and surgical interventions to treat painful cubital tunnel syndrome, radial tunnel syndrome, elbow instability, or olecranon bursitis. Well-designed and well-conducted RCTs are clearly needed in this field.

The efficacy of dextrose prolotherapy for temporomandibular joint hypermobility: a preliminary prospective, randomized, double-blind, placebo-controlled clinical trial.

PURPOSE: The aim of this study was to assess the efficacy of dextrose prolotherapy for the treatment of temporomandibular joint (TMJ) hypermobility. PATIENTS AND METHODS: A prospective, randomized, double-blind clinical study using a placebo control was carried out. Twelve patients with painful subluxation or dislocation of the TMJ were randomly assigned to 1 of 2 equal-sized groups. Patients in the active group received 4 injections of dextrose solution (2 mL of 10% dextrose and 1 mL of 2% mepivacaine) for each TMJ, each 6 weeks apart, whereas patients in the placebo group received injections of placebo solution (2 mL of saline solution and 1 mL of 2% mepivacaine) on the same schedule. A verbal scale expressing TMJ pain on palpation, maximal mouth opening (MMO), clicking sound, and frequency of luxations (number of locking episodes per month) were assessed at each injection appointment just before the injection procedure and 3 months after the last injection. The collected data were then statistically analyzed. RESULTS: By the end of the study, each group showed significant improvement in TMJ pain on palpation and number of locking episodes and insignificant improvement in clicking sound. With the exception of the MMO, there were no statistically significant differences throughout the study intervals between the active and placebo groups. The active group showed a significant reduction in MMO at the 12th week postoperatively. Differences compared with mean baseline value remained significant at the end of the follow-up period. On the other hand, the placebo group showed an insignificant difference in MMO throughout the study periods. For the last 2 intervals, the placebo group showed statistically significantly higher mean MMO values than the active group. By the end of the 12th postoperative week, the percentages of decrease in MMO were significantly greater in the active group. CONCLUSION: Prolotherapy with 10% dextrose appears promising for the treatment of symptomatic TMJ hypermobility, as evidenced by the therapeutic benefits, simplicity, safety, patients' acceptance of the injection technique, and lack of significant side effects. However, continued research into prolotherapy's effectiveness in patient populations with large sample sizes and long-term follow-up is needed.

[Thoracic spine pseudarthrosis treated by transpleural corporectomy and bone morphogenic protein]. / Pseudarthrose du rachis thoracique, traitée par corporectomie transpleurale et protéine ostéo-inductrice.

BACKGROUND AND PURPOSE: Traumatic thoracic spine instability is a rare but difficult-to-treat entity, particularly above T5 where pedicle screwing is widely regarded as an unsatisfactory option and anterior surgery is considered difficult because of the anatomic relationship with the shoulder and large vessels. METHODS: A case of T4 and T5 pseudarthrosis after posterior fixation is reported. It was treated with transpleural corpectomy and fixation, with bone morphogenic protein used to obtain rapid arthrodesis between T3 and T6. No bracing or second posterior fixation was used. RESULT: At 45 days of follow-up, the patient was without pain and the neurologic examination was normal. The CT scan showed bony bridges across all fracture lines. Complete cure of this pseudarthrosis was achieved with a single surgery. At the 12-month follow-up, the clinical status was normal. CONCLUSIONS: The use of bone morphogenic proteins might be of great help in rare but challenging cases of spinal pseudarthrosis, with a quick return to normal activity after a single-stage surgery.

Preliminary evaluation of histological changes found in a mechanical arthropatic temporomandibular joint (TMJ) exposed to an intra-articular Hyaluronic acid (HA) injection, in a rat model.

OBJECTIVE: This study investigates the histological effects of Hyaluronic acid injections in the treatment of induced temporomandibular joint (TMJ) osteoarthritis in rats. STUDY DESIGN: Twenty-four male Wister rats were subjected to induced mechanical osteoarthritis by manual hypermobility for 10 successive days. Animals were then divided into two groups; group I (control) and group II (experimental). Ten days after the induction of hypermobility, the right TMJ of the experimental animals was injected with a dose of 0.12 mg HA intra-articularly and 0.12 mg saline was injected into the left joint; while animals in the control group were left without any treatment. Two rats from group I were killed at one, two and six weeks; while 6 animals from group II were killed at one, two and four weeks post injection. RESULTS: The disk of the right joints in the experimental animals was of normal thickness and there was an increase in the thickness of the fibrocartilagenous layer. In the left joint; ulcerative changes in the disk were evident where the fibres were not well oriented and scalloped areas in the temporal bone area were present denoting osteoclastic activity. CONCLUSIONS: Repeated intra-articular TMJ injection of Hyaluronic acid appears to be a safe and effective way of inhibiting the progression of osteoarthritic changes in the joint through development of articular cartilage and reducing fibrous tissue proliferation.

Exogenous collagen crosslinking of the intervertebral disc restores joint stability after lumbar posterior decompression surgery.

STUDY DESIGN: In vitro evaluation of a chemical, injectable intervention for discectomy induced destabilization. OBJECTIVE: To investigate the ability of two collagen crosslinking agents to restore mechanical properties to lumbar joints destabilized by surgical decompression procedures. SUMMARY OF BACKGROUND DATA: Posterior decompression surgery is a common procedure indicated for tissue pathology that interferes with surrounding neural structures. Previous in vitro, analytical, and clinical studies have shown that removal of load-supporting tissue can compromise joint stability mandating some form of postsurgical stabilization. Currently, no nonsurgical treatments are capable of restoring stability and preventing subsequent degeneration. Exogenous crosslinking of intact discs has shown a fourfold increase in joint stability. METHODS: Fifteen bovine lumbar intervertebral joints were randomly separated into methylglyoxal or genipin treatment groups. Flexion-extension flexibility was quantified in three conditions: intact, postdecompression surgery, and after crosslinking reagent injections. Instability was quantified by calculating neutral zone (NZ), percentage of hysteresis, range of motion, and percentage of strain energy. RESULTS: Simulated surgical decompression increased NZ 111% (P = 0.009), 28% (P = 0.004), range of motion 57% (P = 0.003), and decreased strain energy 37% (P = 0.004). For those discs undergoing methylglyoxal treatment NZ was subsequently reduced 68% (P = 0.012), hysteresis 28% (P = 0.018), range of motion 29% (P = 0.012), and strain energy was increased 71% (P = 0.018). For discs subjected to genipin treatment, NZ was reduced 52% (P = 0.018), hysteresis 23% (P = 0.012), range of motion 44% (P = 0.017), and strain energy was increased 66% (P = 0.012). Mean NZ was lower than intact mean after both methylglyoxal and genipin treatments, 10% and 17% less, respectively, but these differences were not significant. Mean values for all other parameters posttreatment were within 6% of the corresponding intact mean values. CONCLUSION: Injections of crosslinking reagents into lumbar intervertebral discs after simulated decompression surgery restored joint stability according to all parameters. Similar results were found for genipin and methylglyoxal reagents. Implementing exogenous collagen crosslinking as an adjunct to current surgical decompression procedures may be beneficial in preventing or delaying subsequent spinal instability and degeneration.

Nonoperative treatment of superior labrum anterior posterior tears: improvements in pain, function, and quality of life.

BACKGROUND: Although there are multiple reports documenting successful outcomes with operative treatment of superior labrum anterior posterior (SLAP) tears, there are few reports on the results of nonoperative treatment. HYPOTHESIS: Nonoperative treatment of SLAP tears will result in improved outcomes over pretreatment values using validated, patient-derived outcome instruments. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 371 patients with a diagnosis of labral tear at our institution were mailed a questionnaire that included the following validated, patient-derived outcome assessment instruments: Short Form 36 (SF-36), European Quality of Life measure (EuroQol), visual analog pain scale (VAS), American Shoulder and Elbow Surgeons (ASES) score, and simple shoulder test (SST). Sixty-six surveys did not reach the patients because of incorrect addresses, and 50 surveys were returned, for a 16.4% (50 of 305) response rate. Of the patients with a clinically documented SLAP lesion (positive O'Brien test, pain at the bicipital groove, and positive magnetic resonance imaging) and sufficient follow-up data (minimum 1 year), 39 patients who met the criteria returned the survey and 19 had nonoperative treatment. Twenty patients (51%) from the overall surveyed group were considered nonoperative treatment failures and had arthroscopic surgical reconstruction. Nonoperative treatment consisted of nonsteroidal anti-inflammatory drugs and a physical therapy protocol focused on scapular stabilization exercises and posterior capsular stretching. Statistical analysis was performed using the paired t test; values of P < .05 were considered significant. RESULTS: At an average follow-up of 3.1 years, function improved significantly (ASES function 30.8 to 45.0 [P < .001]; ASES total 58.5 to 84.7 [P = .001], SST 8.3 to 11.0 [P = .02]) in those patients with successful nonoperative treatment. Quality of life also improved after treatment (EuroQol 0.76 to 0.89, P = .009). Pain relief was significant, as VAS pain scores decreased from 4.5 to 2.1 (P = .043). All patients with successful nonoperative treatment returned to sports. Seventy-one percent of all athletes were able to return to preparticipation levels, but only 66% of overhead athletes returned to their sport at the same or higher level. CONCLUSION: Using validated, patient-derived outcome instruments, the present study shows that successful nonoperative treatment of superior labral tears results in improved pain relief and functional outcomes compared with pretreatment assessments. Although 20 patients (51%) in this group elected surgery and may be considered nonoperative treatment failures, those patients with successful nonoperative treatment had significant improvements in pain, function, and quality of life. Return to sports was comparable with patients with successful surgical treatment, although return to overhead sports at the same level was difficult to achieve (66%). Based on these findings, a trial of nonoperative treatment may be considered in patients with the diagnosis of isolated superior labral tear. In overhead athletes and in those patients where pain relief and functional improvement is not achieved, surgical treatment should be considered.

Comparison of botulinum toxin type A injection and soft-tissue surgery to treat hip subluxation in children with cerebral palsy.

OBJECTIVE: To compare the effects of botulinum toxin type A (BTX-A) injection into the hip adductor muscles on hip displacement with soft-tissue surgery and assess the factors related to a favorable outcome after intervention in children with bilateral spastic cerebral palsy (CP). DESIGN: Retrospective chart review with regard to radiographic findings. SETTING: University hospital. PARTICIPANTS: Children with CP (N=194). INTERVENTIONS: BTX-A injection and soft-tissue surgery into the hip adductor muscles. MAIN OUTCOME MEASURE: The Reimers hip migration percentage (MP). RESULTS: Sixty-nine children did not receive any therapeutic intervention for hip displacement, whereas 60 children underwent soft-tissue surgery and 65 children took BTX-A injection for the spasticity of their hip muscles. MP was measured on each radiograph of the pelvis. The annual change of MP was improved in both the soft-tissue surgery and BTX-A groups, whereas it worsened in the nonintervention group. The annual improvement of MP in the BTX-A group did not differ significantly from that of the soft-tissue surgery group. The improvement in hip displacement after therapeutic intervention was greater in young children and high-functioning groups compared with older children and low-functioning groups. Hip displacement was progressive in the severely hip subluxated group despite therapeutic intervention. CONCLUSIONS: Comparable effects of BTX-A injection to soft-tissue surgery in our study suggest that BTX-A injection, if timely reinjected, may replace soft-tissue surgery as a prophylactic procedure against progressive hip subluxation or dislocation in children. Age at intervention, functional level, and initial MP before therapeutic intervention were the factors affecting the outcomes.

The effect of ketorolac on anteroposterior knee laxity after anterior cruciate ligament reconstruction.

UNLABELLED: This study investigated the effect of ketorolac on anteroposterior laxity after anterior cruciate ligament (ACL) reconstruction. A total of 168 ACL reconstructions performed between July 2003 and November 2004 were reviewed. The 6-week KT-1000 manual maximum differences between the ACL-reconstructed knee and nonoperative knee were compared for patients who received ketorolac and those who did not. Mean manual maximum difference in anterior displacement was 0.6 mm in the ketorolac group and -0.6 mm in the non-ketorolac group (P=.03). When bone-patellar tendon grafts were analyzed as a separate group, mean manual maximum difference was 0.5 mm in the ketorolac group and -1.4 mm in the non-ketorolac group (P=.007). When hamstring grafts were analyzed separately, mean manual maximum difference was 0.7 mm in the ketorolac group and 0.4 mm in the non-ketorolac group (P=.59). The use of ketorolac during bone-patellar tendon autograft ACL reconstruction was associated with increased AP laxity at 6 weeks postoperatively. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Nociceptive nerve activity in an experimental model of knee joint osteoarthritis of the guinea pig: effect of intra-articular hyaluronan application.

Nociceptive impulse activity was recorded extracellularly from single A delta and C primary afferents of the guinea pig's medial articular nerve after induction of an experimental osteoarthritis in the knee joint by partial medial menisectomy and transection of the anterior cruciate ligament (PMM+TACL). Also, the analgesic effects of intra-articular hyaluronan solutions were evaluated. Healthy, PMM+TACL operated, sham-operated (opening of the joint capsule without PMM and TACL surgery) and acutely inflamed (intra-articular kaolin-carrageenan, K-C) animals were used. The stimulus protocol consisted of torque meter-controlled, standardized innocuous and noxious inward and outward rotations of the joint. This stimulus protocol of 50 s duration was repeated every 5 min for 70 min. One day, one week and three weeks after PMM+TACL, the movement-evoked discharges of A delta articular afferents were increased significantly over values found in sham-operated animals. The discharges of C fibers were significantly augmented only one week after PMM+TACL surgery. Filling of the joint cavity with a high viscosity hyaluronan solution (hylan G-F 20, Synvisc) immediately and three days after surgery reduced significantly the enhanced nerve activity observed in joint afferent fibers one day and one week after surgery. Augmentation of movement-evoked discharges in K-C acutely inflamed knee joints was similar to that observed one week after PMM+TACL. Our results indicate that in the PMM+TACL model of osteoarthritis in guinea pigs, enhancement of nociceptive responses to joint movement was primarily associated to post-surgical inflammation. Intra-articular injection of an elastoviscous hyaluronan solution reduced the augmented nerve activity.

OK-432 (Picibanil) sclerotherapy for recurrent dislocation of the temporomandibular joint in elderly edentulous patients: Case reports.

Dislocation of the temporomandibular joint (TMJ) is a thorny problem not only for a patient but also a doctor. Especially for the elderly edentulous patients, it is very hard to treat the condition although there are many surgical and non-surgical procedures. We successfully treated it in two elderly edentulous patients by injection of OK-432 as a sclerosing agent.

Effect of intraarticular hyaluronan injection on vertical ground reaction force and progression of osteoarthritis after anterior cruciate ligament transection.

OBJECTIVE: To determine if intraarticular (IA) injection of hyaluronan (HA) into the canine knee after anterior cruciate ligament transection (ACLT) alters the progression of osteoarthritis (OA) and the perception of pain in this model. METHODS: OA was induced in 30 adult dogs of mixed breed by ACLT. The dogs were divided into 3 groups and given 5 weekly IA injections into the unstable knee during Weeks 1-5 and 13-17. The prophylactic treatment group received HA in the first series and saline during the second series. The therapeutic group received saline in the first series and HA in the second series. The control group received saline during both injection series. The progression of joint damage of OA was evaluated by arthroscopy 12 weeks after ACLT and by gross examination 32 weeks after ACLT. Histologic and biochemical changes of OA were evaluated. Loading of the unstable limb during gait was determined by force-plate analysis before surgery, after each series of injections, and the week before euthanasia. RESULTS: Arthroscopic examination 12 weeks after ACLT revealed OA changes in the cruciate-deficient knees. Chondropathy scores ranged from 0 to 8 (possible range 0-65). The mean chondropathy score was 2.5 +/- 1.3 (mean +/- SD) for the controls, 2.5 +/- 2.5 for the therapeutic group, and 2.1 +/- 1.3 for the prophylactic group. At the termination of the experiment 32 weeks after ACLT, the gross chondropathy scores were 14.0 +/- 5.2 for controls, 17.6 +/- 6.8 for the therapeutic group, and 13.3 +/- 5.0 for the prophylactic group. There were no significant differences among the means of the gross scores, the histologic scores, or biochemical composition of articular cartilage. The peak vertical ground reaction force (VGRF) generated by the unstable limb was reduced by ~60% after ACLT, and slowly increased to ~75% of the baseline value over the 32 weeks after ACLT. HA injection had no effect on the VGRF or on the pathologic changes of OA. CONCLUSION: Intraarticular HA injection did not alter the progression of OA in the cruciate-deficient canine knee or alter the loading of the unstable limb.