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  • Author or Editor: Michael G. Conzemius x
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Abstract

Objective—To document the caregiver placebo effect in owners and veterinarians of dogs with lameness from osteoarthritis.

Design—Prospective, randomized, double-blinded, placebo-controlled, multicenter clinical trial.

Animals—58 dogs with lameness secondary to osteoarthritis.

Procedures—Dogs enrolled in the placebo arm of an FDA-approved study were evaluated to determine the relationship between subjective (caregiver responses) and objective (force platform gait analysis) patient outcome measures.

Results—A caregiver placebo effect for owners evaluating their dog's lameness occurred 39.7% of the time. A caregiver placebo effect occurred 44.8% of the time when veterinarians examined dogs for lameness at a walk, 44.8% of the time when veterinarians examined dogs for lameness at a trot, and 43.1% of the time when veterinarians evaluated dogs for signs of pain on palpation of the joint. This effect was significantly enhanced with time. Mean ground reaction forces (GRFs) remained unchanged for dogs during treatment with the placebo. Individually, of 58 dogs, 5 had GRFs that worsened by ≥ 5% over 42 days, 7 had GRFs that improved by ≥ 5% over 42 days, and 46 had GRFs that remained unchanged.

Conclusions and Clinical Relevance—A caregiver placebo effect was common in the evaluation of patient response to treatment for osteoarthritis by both pet owners and veterinarians. Force platform gait analysis was an unbiased outcome measure for dogs with lameness from osteoarthritis. A caregiver placebo effect should be considered when interpreting owner and veterinary reports of patient response to treatment.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effects of early postoperative rehabilitation on limb function in dogs after surgery for ruptured cranial cruciate ligament (RCCL).

Design—Prospective clinical study.

Animals—51 client-owned dogs.

Procedure—Dogs weighing between 20 and 40 kg (44 to 88 lb) that had RCCL and medial meniscal injury were studied. After removal of the RCCL and complete medial meniscectomy, the stifle joint was stabilized by use of a lateral retinacular stabilization technique. Twenty-five dogs were included in a postoperative rehabilitation group, and 26 dogs were included in an exercise-restricted group. Limb function (peak vertical force [PVF] and vertical impulse [VI]) was determined before surgery and 6 months after surgery, using force platform gait analysis.

Results—Prior to surgery, mean PVF and VI in affected limbs were similar between groups. Six months after surgery, PVF and VI were significantly increased in dogs of both groups. However, PVF and VI in dogs in the rehabilitation group were significantly greater than those of dogs in the exercise-restricted group. At this time, differences in limb function (as measured by PVF and VI) between the repaired and normal limbs were not evident in dogs in the rehabilitation group. Conversely, limb function in the repaired limb of dogs in the exercise-restricted group was still significantly less than that of the normal limb.

Conclusion and Clinical Relevance—Dogs that have surgery for RCCL and a torn medial meniscus benefit from postoperative rehabilitation; rehabilitation should be considered part of the postoperative management of these patients. (J Am Vet Med Assoc 2002;220:1325–1330)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine hip, stifle, and tarsal joint ranges of motion (ROM) and angular velocities during swimming and walking in healthy dogs and dogs with surgically corrected cranial cruciate ligament (CCL) rupture.

Design—Prospective clinical study.

Animals—13 healthy dogs and 7 dogs with CCL rupture.

Procedure—Dogs with CCL rupture were enrolled in a postoperative aquatic rehabilitation program and evaluated 21 to 35 days after surgery. Dogs were filmed while swimming in a pool and while walking at a fast (1.3 m/s) or slow (0.9 m/s) pace on a treadmill. Maximal angles of extension and flexion, ROM, and angular velocities were calculated.

Results—In healthy dogs, swimming resulted in a significantly greater ROM in the hip joint than did walking, but in dogs with CCL rupture, ROM of the hip joint did not vary with swimming versus walking. For dogs in both groups, swimming resulted in significantly greater ROM of the stifle and tarsal joints than did walking, primarily because of greater joint flexion. Stifle joint ROM was significantly lower in dogs with CCL rupture than in healthy dogs, regardless of whether dogs were swimming or walking.

Conclusions and Clinical Relevance—Results suggested that following surgical management of a ruptured CCL in dogs, swimming resulted in greater ROM of the stifle and tarsal joints than did walking. This suggests that if ROM is a factor in the rate or extent of return to function in these dogs, then aquatic rehabilitation would likely result in a better overall outcome than walking alone. (J Am Vet Med Assoc 2003;222:739–743)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine short- and long-term rates of successful outcomes of surgical and nonsurgical treatments for overweight dogs with cranial cruciate ligament rupture (CCLR).

Design—Prospective, randomized, clinical trial.

Animals—40 client-owned overweight dogs with unilateral CCLR.

Procedures—Dogs were randomly assigned to nonsurgical (physical therapy, weight loss, and NSAID administration) or surgical (tibial plateau leveling osteotomy) treatment groups; dogs in both groups received the same nonsurgical treatments. Dogs were evaluated immediately before and 6, 12, 24, and 52 weeks after initiation of treatments via owner questionnaires, gait analysis, and dual-energy x-ray absorptiometry. A successful outcome was defined as an affected limb net ground reaction force > 85% of the value for healthy dogs and a ≥ 10% improvement in values of questionnaire variables.

Results—Owner questionnaire responses indicated dogs in both groups improved during the study, but dogs in the surgical treatment group seemed to have greater improvement. Body fat percentages for dogs in both treatment groups significantly decreased during the study. Surgical treatment group dogs had significantly higher peak vertical force for affected limbs versus nonsurgical treatment group dogs at the 24- and 52-week evaluation times. Surgical treatment group dogs had a higher probability of a successful outcome (67.7%, 92.6%, and 75.0% for 12-, 24-, and 52-week evaluations, respectively) versus nonsurgical treatment group dogs (47.1%, 33.3%, and 63.6% for 12-, 24-, and 52-week evaluations, respectively).

Conclusions and Clinical Relevance—Overweight dogs with CCLR treated via surgical and nonsurgical methods had better outcomes than dogs treated via nonsurgical methods alone. However, almost two-thirds of the dogs in the nonsurgical treatment group had a successful outcome at the 52-week evaluation time.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To document peak vertical force (PVF) and vertical impulse (VI) in the pads of Greyhounds and Labrador Retrievers.

Animals—8 Greyhounds and 8 Labrador Retrievers.

Procedure—Velocity and acceleration were restricted to ranges of 0.9 to 1.1 m/s and –0.1 to 0.1 m/s2, respectively. The PVF and VI measurements were collected from digital pad (DP)-2, -3, -4, and -5 and the metacarpal pad (McP) or metatarsal pad (MtP) of each limb in each dog.

Results—We found no significant differences between the left and right forelimbs or hind limbs for any pad in either breed. Vertical forces in the forelimb were always greater than those in the hind limb. The PVF in the forelimbs of Greyhounds was greatest in DP-3, -4, and -5 and DP-3, DP-4, and the MtP in the hind limbs. The VI in Greyhound forelimbs was greatest in DP-3, -4, and -5 but greatest in DP-4 in the hind limbs. The PVF in the forelimbs of Labrador Retrievers was greatest in the McP, whereas in the hind limbs it was greatest in DP-4. The VI in Labrador Retriever forelimbs was greatest in DP-3, DP-4, and the McP but greatest in DP-3 and -4 in the hind limbs. Significant differences were detected in load distribution between the breeds.

Conclusions and Clinical Relevance—This study confirms that DP-3 and DP-4 are major weight-bearing pads in dogs. However, loads were fairly evenly distributed, and DP-5 and the McP or MtP bear a substantial amount of load in both breeds. (Am J Vet Res 2004;65:1497–1501)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of exogenous growth hormone or somatostatin on chemotherapeutic efficacy in athymic (nude) rats with osteosarcoma. Animals—66 female athymic rats.

Procedure—Osteosarcoma was induced at an intratibial site. Rats were randomly allotted to 6 treatment groups. Rats were treated with saline (0.9% NaCl) solution alone, platinum, diammine [1,1-cyclobutane dicaboxylato (2-)-0,0']-(SP-4-2) (CBDCA; ie, carboplatin) plus saline solution, somatostatin alone, somatostatin plus CBDCA, growth hormone alone, or growth hormone plus CBDCA. Variables measured included estimated WBC count and percentage of neutrophils, plasma concentration of insulin-like growth factor I (IGF-I), body weight, tumor volume, weight of primary tumor, survival time, and distant metastasis at time of death.

Results—Tumors formed at the injection sites in all rats. Treatment with growth hormone increased, and treatment with somatostatin decreased, plasma IGF-I concentration. Treatment with growth hormone or somatostatin altered CBDCA efficacy, as determined by evaluation of mean and median survival times. Metastatic pulmonary disease developed in 63 of 64 rats.

Conclusions and Clinical Relevance—The technique used here reliably induced local osteosarcomas and metastatic pulmonary disease. Treatment with growth hormone and CBDCA or somatostatin may improve chemotherapeutic efficacy without increasing toxic effects.

Implications for Human Medicine—Results reported here may be useful in the study of osteosarcoma in humans. (Am J Vet Res 2000;61:646–650)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare tibial plateau angle (TPA) between Greyhounds without damage to the cranial cruciate ligaments and Labrador Retrievers with and without damage to the cranial cruciate ligaments.

Design—Clinical study.

Animals—87 client-owned dogs and 15 research colony Greyhounds.

Procedure—Standing position, horizontal-beam radiography was performed on Greyhounds and unaffected Labrador Retrievers to determine standing TPA. Lateral radiography of the stifle joint was performed on all dogs to determine traditional TPA. Age and body weight were recorded for unaffected and affected Labrador Retrievers.

Results—Greyhounds had mean standing TPA of 1.56° and mean traditional TPA of 22.50°. Unaffected Labrador Retrievers had mean standing TPA of 3.52° and traditional TPA of 27.97°. Affected Labrador Retrievers had mean traditional TPA of 25.55°. No significant difference was found in mean standing TPA between Greyhounds and unaffected Labrador Retrievers. Standing TPAs in Greyhounds and unaffected Labrador Retrievers were not significantly different from a plane drawn parallel to the ground. Significant differences in traditional TPAs were detected among all 3 groups.

Conclusions and Clinical Relevance—Greyhounds had mean traditional TPA of 22.50°; similar angles should be considered normal for dogs. Although affected Labrador Retrievers had mean traditional TPA that was significantly greater than that of Greyhounds, the steepest TPA was found in unaffected Labrador Retrievers. Because Greyhounds and unaffected Labrador Retrievers had similar standing TPAs, we conclude that although TPA may be associated with damage to the cruciate ligaments, many dogs with a steep TPA do not develop cruciate ligament disease. (J Am Vet Med Assoc 2002;221:1426–1429)

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To test ex vivo mechanical properties of 4 allograft fixation techniques for cranial cruciate ligament (CCL) replacement.

SAMPLE 30 stifle joints from canine cadavers.

PROCEDURES CCL-deficient stifle joints repaired by 1 of 4 techniques (n = 6/group) and CCL-intact stifle joints (control group; 6) were mechanically tested. Three repair techniques involved a patella-patella ligament segment (PPL) allograft: a tibial and femoral interference screw (PPL-2S), a femoral interference screw and the patella seated in a tapering bone tunnel in the tibia (PPL-1S), or addition of a suture and a bone anchor to the PPL-1S (PPL-SL). The fourth technique involved a deep digital flexor tendon (DDFT) allograft secured with transverse femoral fixation and stabilized with a tibial interference screw and 2 spiked washers on the tibia (DDFT-TF). The tibia was axially loaded at a joint angle of 135°. Loads to induce 3, 5, and 10 mm of femoral-tibia translation; stiffness; and load at ultimate failure with the corresponding displacement were calculated. Group means were compared with a multivariate ANOVA.

RESULTS Mean ± SD load for the intact (control) CCL was 520.0 ± 51.3 N and did not differ significantly from the load needed to induce 3 mm of femoral-tibial translation for fixation techniques PPL-SL (422.4 ± 46.3 N) and DDFT-TF (654.2 ± 117.7 N). Results for the DDFT-TF were similar to those of the intact CCL for all outcome measures.

CONCLUSIONS AND CLINICAL RELEVANCE The DDFT-TF yielded mechanical properties similar to those of intact CCLs and may be a viable technique to test in vivo.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate short-term postoperative forelimb function after scalpel and laser onychectomy in cats.

Design—Randomized, prospective study.

Animals—20 healthy adult cats.

Procedures—Cats were randomly assigned to the laser (n = 10) or scalpel (10) onychectomy group. Unilateral left forelimb onychectomy was performed. In the scalpel group, a tourniquet was used during surgery and a bandage was applied after surgery. Pressure platform gait analysis was performed prior to and 1, 2, 3, and 12 days after onychectomy. Peak vertical force (PVF), vertical impulse, and the ratio of the PVF of the left forelimb to the sum of the remaining limbs (PVF ratio) were used as outcome measures.

Results—The laser onychectomy group had significantly higher ground reaction forces on days 1 and 2 and significantly higher PVF ratio on day 12, compared with the scalpel group. Similarly, significant differences were found in change in ground reaction forces on days 1 and 2 and the PVF ratio on day 12, compared with day −1. No cats required rescue analgesia during the course of the study. One cat in the laser group had signs of depression and was reluctant to walk on day 2 after surgery, had physical examination findings consistent with cardiac insufficiency, and was euthanized.

Conclusions and Clinical Relevance—Cats had improved limb function immediately after unilateral laser onychectomy, compared with onychectomy with a scalpel, tourniquet, and bandage. This improved limb function may result from decreased pain during the 48 hours following unilateral laser onychectomy.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the analgesic effects of topical administration of bupivacaine, IM administration of butorphanol, and transdermal administration of fentanyl in cats undergoing onychectomy.

Design—Prospective study.

Animals—27 healthy adult cats.

Procedure—Cats were randomly assigned to 1 of 3 treatment groups, and unilateral (left forefoot) onychectomy was performed. Gait analysis was performed before and 1, 2, 3, and 12 days after surgery. All forces were expressed as a percentage of the cat's body weight.

Results—On day 2, peak vertical force (PVF) was significantly decreased in cats treated with bupivacaine, compared with cats treated with butorphanol or fentanyl. The ratio of left forelimb PVF to PVF of the other 3 limbs was significantly lower on day 2 in cats treated with bupivacaine than in cats treated with fentanyl. No significant differences in vertical impulse (VI) were found between groups on any day. Values for PVF, VI, and the PVF ratio increased progressively following surgery. However, for all 3 groups, values were still significantly decreased, compared with baseline values, 12 days after surgery.

Conclusions and Clinical Relevance—Results suggest that limb function following onychectomy is significantly better in cats treated with fentanyl transdermally or butorphanol IM than in cats treated with bupivacaine topically. Regardless of the analgesic regimen, limb function was still significantly reduced 12 days after surgery, suggesting that long-term analgesic treatment should be considered for cats undergoing onychectomy. Irrigation of the surgical incisions with bupivacaine prior to wound closure cannot be recommended as the sole method for providing postoperative analgesia in cats undergoing onychectomy. (J Am Vet Med Assoc 2005;227:89–93)

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in Journal of the American Veterinary Medical Association