The effect of body condition on postoperative recovery of dachshunds with intervertebral disc disease treated with postoperative physical rehabilitation.

OBJECTIVE: To determine the impact of obesity on postoperative recovery from thoracolumbar hemilaminectomy in dachshunds treated with rehabilitation. STUDY DESIGN: Prospective observational trial. ANIMALS: Thirty-two dachshunds with thoracolumbar intervertebral disk disease and pain perception. METHODS: Dachshunds were entered into the study after unilateral thoracolumbar hemilaminectomy. Lean muscle and fat contents were measured with dual-energy x-ray absorptiometry (DEXA) at the beginning and at week 12 of the study. Aggressive rehabilitation was performed 1, 2, 4, and 6 weeks after surgery. Logistic regressions were used to determine the odds ratios between potential risk factors (age, duration of clinical signs, weight, body condition score, percentage body fat, percentage lean muscle mass, and disability index [DI] score at presentation) and return benchmarks of recovery. RESULTS: Body condition score, percentage body fat, percentage lean muscle mass, weight, and age did not influence the odds ratio for recovery. An increase in preoperative DI score was associated with increased risk of a slow postoperative recovery (P < .05). The odds ratios were 2.5, 4.8, and 1.8 for >7 days until standing, > 30 days until strong ambulation, and failure to return to normal within the study period, respectively. On average, dogs lost weight (2.2 kg) and body fat (2.4%) but gained muscle mass (3.0%) over the study period (P < .05). CONCLUSION: Preoperative disability but not body condition was a risk factor for a slow recovery after thoracolumbar hemilaminectomy in dachshunds with rehabilitation. CLINICAL SIGNIFICANCE: A slower recovery is likely with increased preoperative disability, but body condition does not seem to affect the postoperative prognosis of dachshunds treated with rehabilitation.

Three dimensional morphologic analysis of the lateral surface of the canine femur.

OBJECTIVES: Analyze the lateral plating surface of the femur to obtain bend and twist angles in dogs with non-chondrodystrophic phenotype. STUDY DESIGN: Retrospective computed tomography (CT) morphologic analysis. SAMPLE POPULATION: Historical cohort, hindlimb CT scans (n = 30). MATERIALS AND METHODS: The CT images of 30 normal femurs were uploaded to surgical planning software and 13 points of interest and their respective bend/twist angles were identified on the lateral surfaces. Mean, standard deviation, coefficient of variation (CV), and range were calculated for each bend/twist angle. Hierarchal clustering and fast Fourier Analyses were used to segment the cohort. Distribution of age, breed, sex, and weight was evaluated between clusters with an exact Wilcoxon-Mann-Whitney test. RESULTS: The CV of bending ranged from 17% to 46% and for twisting ranged from 21% to 58%. The greater trochanter was the most pronounced bend on the lateral surface of the femur (mean ± SD 8.11 ± 1.35°, CV 17%), and the supracondylar region of the distal femur was the most marked twist (mean ± SD 48.98 ± 10.06°, CV 21%). Although there were no differences between dogs in proximal femur anatomy, 2 clusters of 9 and 21 dogs each were identified due to differences in bend/twist angles in the distal femur. There was no difference between clusters for age (P = .85), breed (P = .62), and sex (P = .15); however, weight differed (P = .03) but was not predictive. CONCLUSION: Although distal femoral lateral surfaces varied sufficiently to result in 2 population clusters, further analysis is needed to determine if the differences prevent using the mean bending and twisting parameters as a template for clinical applications.

Effect of the use of carprofen in dogs undergoing intense rehabilitation after lateral fabellar suture stabilization.

OBJECTIVE: To determine whether carprofen, a commercially available NSAID, would decrease perceived exertion and signs of pain in dogs and therefore increase muscle mass and hind limb function without decreasing range of motion after lateral fabellar suture stabilization. DESIGN: Randomized, blinded, controlled clinical trial. ANIMALS: 35 dogs with cranial cruciate ligament rupture and lateral fabellar suture stabilization followed by rehabilitation. PROCEDURES: All dogs underwent surgical stabilization of cranial cruciate ligament rupture by placement of a lateral fabellar suture. Dogs received carprofen (2.2 mg/kg [1 mg/lb], PO, q 12 h) for the first 7 days after surgery and underwent concentrated rehabilitation exercises during weeks 3, 5, and 7 after surgery. Eighteen dogs also received carprofen (2.2 mg/kg, PO, q 12 h) during the weeks of concentrated rehabilitation. Outcomes were measured by a single investigator, who was blinded to group assignments, using pressure platform gait analysis, goniometry, thigh circumference, and mean workout speed at a consistent level of exertion. RESULTS: There were no differences between the 2 groups in ground reaction forces, thigh circumference, or exertion (mean workout speed) over time or at any individual time point. However, both groups improved significantly over time for all outcome measures. CONCLUSIONS AND CLINICAL RELEVANCE: Providing carprofen to dogs during concentrated rehabilitation after lateral fabellar suture stabilization did not improve hind limb function, range of motion, or thigh circumference, nor did it decrease perceived exertion, compared with control dogs. Carprofen was not a compulsory component of a physical therapy regimen after lateral fabellar suture stabilization.

Evaluation of S-adenosyl l-methionine in a double-blinded, randomized, placebo-controlled, clinical trial for treatment of presumptive osteoarthritis in the dog.

OBJECTIVE: To evaluate the efficacy of S-adenosyl l-methionine (SAMe) in the treatment of clinically inferred canine osteoarthritis (OA). STUDY DESIGN: Six weeks, double-blinded, placebo-controlled, clinical trial. ANIMALS: Dogs (n=33) with clinical signs, history, and orthopedic exams consistent with OA. METHODS: Dogs were block randomized by body condition score (<6/9, or ≥6/9) into either the placebo or SAMe group. Outcome was assessed using pressure platform gait analysis, examination score, goniometry, and the Canine Brief Pain Inventory (CBPI) at the time of study entrance and at 3 and 6 weeks after entry. Groups were compared using parametric and nonparametric paired tests as appropriate, and numbers needed to treat (NNT) were calculated for the CBPI and peak vertical force (PVF). RESULTS: Both groups (n=15 placebo, n=18 SAMe) had a reduction in mean PVF (P=.02) and vertical impulse (VI; P=.06) from the 1st to 3rd visit. There was no significant difference between the placebo group and SAMe group for PVF, VI, or either part of the CBPI (Severity or Impact). The NNT at 6 weeks for the Severity score was 3, Impact score was 25, and PVF was 45. CONCLUSIONS: These data do not support the use of SAMe as an effective stand alone treatment for reducing clinical signs of OA, as measured by PVF, VI, goniometry, CBPI (both Severity and Impact), and examination score within 6 weeks of treatment.

Comparison of short- and long-term function and radiographic osteoarthrosis in dogs after postoperative physical rehabilitation and tibial plateau leveling osteotomy or lateral fabellar suture stabilization.

OBJECTIVES: To compare short- and long-term functional and radiographic outcome of cranial cruciate ligament (CrCL) injury in dogs treated with postoperative physical rehabilitation and either tibial plateau leveling osteotomy (TPLO) or lateral fabellar suture stabilization (LFS). STUDY DESIGN: Prospective observational clinical study. ANIMALS: Medium to large breed dogs with naturally occurring CrCL injury (n=65). METHODS: Dogs with CrCL injury were treated with either TPLO or LFS and with identical physical rehabilitation regimes postoperatively. Limb peak vertical force (PVF) was measured preoperatively and at 3, 5, and 7 weeks, and 6 months and 24 months postoperatively. Stifles were radiographically assessed for osteoarthrosis (OA) preoperatively and 24 months postoperatively. RESULTS: Thirty-five dogs had LFS and 30 dogs had TPLO. Radiographic OA scores were significantly increased at 24 months compared with preoperative scores in all dogs. Radiographic OA scores preoperatively and at 24 months were not significantly different between treatment groups. PVF was significantly increased from preoperative to 24 months among both treatment groups but not significantly different between treatment groups preoperatively or at 3, 5, 7 weeks, 6, or 24 months. CONCLUSION: No significant difference in outcome as determined by ground reaction forces or radiographic OA scores were found between dogs with CrCL injury treated with LFS or TPLO. CLINICAL RELEVANCE: LFS and TPLO remain good options for stabilizing stifles with CrCL injury with all dogs showing significant functional improvement. This study does not support the superiority of either surgical technique.

Evaluation of intra- and interobserver variability and repeatability of tibial plateau angle measurements with digital radiography using a novel digital radiographic program.

OBJECTIVE: To compare the intra- and interobserver variability occurring when observers with differing experience levels measure tibial plateau angles (TPAs) with a novel digital radiographic projection program (tibial plateau leveling osteotomy [TPLO] planning program), the Kodak Picture Archiving and Communications System (PACS), and standard sized printed films (SF). STUDY DESIGN: Cross-sectional study. SAMPLE POPULATION: Dogs (n=36) with cranial cruciate ligament (CCL) rupture that had a TPLO. METHODS: Six observers, divided into 3 equal groups based on experience level, measured TPA on 36 digitally captured radiographic images of tibiae of dogs clinically affected with CCL rupture. Each observer used 3 methods of measuring TPA and repeated the measurements 3 times with each method. The intra- and interobserver variability was compared using the coefficient of variation. RESULTS: Averaged over all replications and images, there was no significant difference (P>.05) in the average variability occurring with each method for all but 1 observer. There was no effect of experience level on measurement variability; however, interobserver variability was significantly less with measurements made with the PACS and TPLO planning program compared with measurements made from SF (P<.05). CONCLUSIONS: Repeated measurements of TPA made using digital images and computer-based measurement programs were significantly less variable between observers than those made from images printed on standard radiographic films. CLINICAL RELEVANCE: Digital radiography and computer-based measurement programs are effective for determining the TPA, allowing less variability in measurements compared with SF. The ability to manipulate the image may allow better identification of anatomic landmarks.

Bilateral iliopsoas muscle contracture and spinous process impingement in a German Shepherd dog.

OBJECTIVE: To report diagnosis and treatment of bilateral iliopsoas muscle contracture in a dog with spinous process impingement. STUDY DESIGN: Case report. ANIMALS: German Shepherd dog. METHODS: A dog with chronic progressive lameness, flexion contracture of the coxofemoral joints, severe pain, and decreased femoral reflexes had severe spondylosis bridging the vertebral bodies from L1 to L4 and enlarged dorsal spinous processes from T8 to L6 with impingement and bony proliferation. Ultrasonographic and magnetic resonance imaging (MRI) findings were consistent with fibrosis, mineralization, and atrophy of the iliopsoas muscles bilaterally which was treated by staged tenectomy of the insertions of the iliopsoas muscles. RESULTS: Because of severe perivascular fibrosis, the femoral vessels required ligation. Bilateral iliopsoas muscle tenectomy improved gait and provided pain relief. Histologic findings were consistent with fibrotic myopathy. CONCLUSIONS: Slow progression of severe clinical signs observed bilaterally in this dog differs from previous reports of iliopsoas myopathy. Findings were similar to the fibrotic myopathy of the gracilis or semitendinosus muscles described in dogs. CLINICAL RELEVANCE: Iliopsoas muscle abnormalities should be considered in dogs with limited hip extension and pain. MRI is useful for diagnosing muscle fibrosis. Iliopsoas tenectomy may improve clinical function in dogs with fibrotic myopathy.

Clinical application of tobramycin-impregnated calcium sulfate beads in six dogs (2002-2004).

Medical records for six dogs treated with tobramycin-impregnated calcium sulfate beads were reviewed for indications, duration of disease, number of beads implanted, complications, radiographic appearance of the beads, and outcomes. Beads were no longer visible on radiographs made 5 weeks after implantation. Osteomyelitis resolved in five of five dogs with follow-up. The lack of complications and the resolution of clinical signs associated with tobramycin calcium sulfate bead implantation support their clinical application in treating osteomyelitis.

Editorial summary of symposium on hypertensive disorders of pregnancy.

PURPOSE OF REVIEW: Hypertensive disorders of pregnancy, particularly the preeclampsia/eclampsia syndrome, remain the leading causes of worldwide pregnancy-related maternal and neonatal mortality and morbidity. This group of conditions are a 'riddle wrapped in a mystery inside an enigma' to quote Winston Churchill. We are fortunate to have contributions from leading clinical experts who have devoted many years of their professional careers attempting to solve this conundrum. RECENT FINDINGS: Dr Jack Moodley has provided us with a perspective on clinical management in underresourced countries. Referral to experts, aggressive treatment of hypertension and use of magnesium sulfate improves care. Dr Shennan focuses on the assessment of risk, close antenatal surveillance and timely delivery. Dr Uzan continues to champion the use of aspirin for prevention of preeclampsia, even though the evidence is contradictory. Dr Sibai addresses the lack of evidence for calcium, vitamin C and E in prevention of preeclampsia. Dr Von Dadelszen is developing a new paradigm for the classification of these disorders and emphasizes the importance of evidence-based intervention. SUMMARY: Evidence suggests that treatment of severe hypertension, seizure prophylaxis with magnesium sulfate, and management by experienced healthcare professionals will improve maternal, fetal and neonatal outcomes. Well designed studies will lead to evidence-based improvement in caring for mothers and babies worldwide.

Clinical applications of demineralized bone matrix: a retrospective and case-matched study of seventy-five dogs.

OBJECTIVES: To evaluate the outcome in dogs treated with demineralized bone matrix (DBM) as an adjunct to orthopedic procedures. STUDY DESIGN: Retrospective and case-match study. ANIMALS: Dogs (n=75). METHODS: Medical records (1999-2006) and radiographs of dogs that had orthopedic procedures (comminuted fractures, tibial plateau leveling osteotomy [TPLO] where correction for tibial rotation created an osteotomy gap, arthrodeses, open corrective osteotomies) where DBM was used were reviewed for signalment, quantity of DBM implanted, duration of exercise restriction, radiographic healing, and complications. Dogs that had TPLO and correction of tibial torsion (n=15), or arthrodesis (n=16) were compared with case-matched controls. Data were analyzed using Kruskal-Wallis test, ANOVA, Tukey's HSD test, and logistic regression analysis. RESULTS: Mean (+/-SD) healing time for orthopedic surgeries with DBM augmentation were 15+/-6.97 (weeks) and complication rate was 19% (14 dogs). Dogs with a TPLO gap filled with DBM were allowed to return to normal exercise 2 weeks earlier than dogs with a well-apposed TPLO site. Radiographic healing, duration of exercise restriction, and timing of destabilization were similar in dogs undergoing carpal and tarsal arthrodesis whether they received DBM, autogenous graft, or both. CONCLUSIONS: DBM can be used to treat uncomplicated bone defects associated with comminuted fracture repairs, open osteotomies, and arthrodeses in dogs. Under these circumstances, clinicians might expect similar clinical outcomes without the possibility of side effects associated with the harvest of autogenous cancellous bone. CLINICAL RELEVANCE: DBM is safe for use in dogs.

Chitosan scaffolds: interconnective pore size and cartilage engineering.

This study was designed to determine the effect of interconnective pore size on chondrocyte proliferation and function within chitosan sponges, and compare the potential of chitosan and polyglycolic acid (PGA) matrices for chondrogenesis. Six million porcine chondrocytes were seeded on each of 52 prewetted scaffolds consisting of chitosan sponges with (1) pores 10 microm in diameter (n=10, where n is the number of samples); (2) pores measuring 10-50 microm in diameter (n=10); and (3) pores measuring 70-120 microm in diameter (n=10), versus (4) polyglycolic acid mesh (n=22), as a positive control. Constructs were cultured for 28 days in a rotating bioreactor prior to scanning electron microscopy (SEM), histology, and determination of their water, DNA, glycosaminoglycan (GAG) and collagen II contents. Parametric data was compared (p=0.05) with an ANOVA and Tukey's Studentized range test. PGA constructs consisted essentially of a matrix containing more cells than normal cartilage. Whereas very few remnants of PGA remained, chitosan scaffolds appeared intact. DNA and GAG concentrations were greater in PGA scaffolds than in any of the chitosan groups. However, chitosan sponges with the largest pores contained more chondrocytes, collagen II and GAG than the matrix with the smallest pores. Constructs produced with PGA contained less water and more GAG than all chitosan groups. Chondrocyte proliferation and metabolic activity improved with increasing interconnective pore size of chitosan matrices. In vitro chondrogenesis is possible with chitosan but the composition of constructs produced on PGA more closely approaches that of natural cartilage.

Evaluation of an osteoconductive resorbable calcium phosphate cement and polymethylmethacrylate for augmentation of orthopedic screws in the pelvis of canine cadavers.

OBJECTIVE: To evaluate the effect of an osteoconductive resorbable calcium phosphate cement (CPC) on the holding power of bone screws in canine pelvises and to compare the effect with that for polymethylmethacrylate (PMMA). SAMPLE POPULATION: 35 pelvises obtained from canine cadavers. PROCEDURE: Each pelvis was sectioned longitudinally. Within each pair of hemipelvises, one 4.0-mm cancellous screw was placed in the sacroiliac (SI) region and another in the iliac body. Similar regions on the contralateral-matched hemipelvis were assigned 1 of 3 augmentation techniques (CPC-augmented 4.0-mm cancellous screws, PMMA-augmented 4.0-mm cancellous screws, and CPC-augmented 3.5-mm cortical screws). Pullout force was compared between matched screws and between treatment groups prior to examination of cross sections for evaluation of cement filling and noncortical bone-to-cortical bone ratio. RESULTS: CPC and PMMA augmentation significantly increased pullout force of 4.0-mm screws inserted in the SI region by 19.5% and 33.2%, respectively, and CPC augmentation significantly increased pullout force of 4.0-mm cancellous screws inserted in the iliac body by 21.2%. There was no difference in the mean percentage augmentation between treatment groups at either location. Cement filling was superior in noncortical bone, compared with filling for cortical bone. Noncortical bone-to-cortical bone ratio was significantly greater in the sacrum (6.1:1) than the ilium (1.3:1). CONCLUSIONS AND CLINICAL RELEVANCE: CPC and PMMA improve the ex vivo holding strength of 4.0-mm cancellous screws in the SI and iliac body regions and SI region, respectively. Cement augmentation may be more effective in areas with greater noncortical bone-to-cortical bone ratios.

Evaluation of 2 cement techniques for augmentation of stripped 1.5 mm screw sites in the distal metaphysis of feline radii.

OBJECTIVE: To evaluate the effect of 2 cement augmentation techniques on pullout strength of 1.5 mm screws placed in stripped 1.5 mm screw sites in the distal metaphysis of feline radii. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Feline radii (21 pairs). METHODS: Treatment groups (n=4) were allocated according to a Latin square design to 4 sites in each pair of radii. Positive and negative controls were a 1.5 mm screw and a screw of the same diameter in a previously stripped screw hole, respectively. Treatment groups were a 1.5 mm screw implanted in a previously stripped screw hole after injection of polymethylmethacrylate (PMMA) or a bioresorbable calcium phosphate cement (CPC, Norian skeletal repair system (SRS)). The ultimate pullout strength was compared between groups. RESULTS: The mean (+/-SEM) pullout strength of screws augmented with either bone cement was less than that of the positive control group and greater than that of the negative control. Injection of CPC or PMMA before screw implantation increased the pullout strength of the negative control by 86.8+/-22.9% and 104.1+/-32.1%, respectively. Holding power of the positive control screws differed from these 2 groups, and was 274.8+/-39.17% higher than that of the negative control. CONCLUSION: Injection of CPC or PMMA increases but does not restore the holding power of stripped 1.5 mm diameter screws. CLINICAL RELEVANCE: The use of CPC (Norian SRS) augmentation of stripped 1.5 mm diameter screws warrants clinical investigation as it combines biomechanical results similar to PMMA with osteoconduction and resorbability.

An animal model for interface tissue formation in cemented hip replacements.

OBJECTIVE: To create a model in sheep for investigation of early changes related to the formation of an interface membrane in hip prosthesis. STUDY DESIGN: Experimental study. ANIMALS: Twenty-four female adult Swiss Alpine sheep. METHODS: Sheep were divided into 2 groups of 12 for unilateral cemented total hip arthroplasty. In Group I, the prosthesis was fixed with retrograde cement gun injection to achieve a complete cement mantle, whereas in Group II a primary cement mantle defect was produced. Groups I and II were further divided into 2 sub-groups with study end points of 2 and 8.5 months after surgery. Radiographs were evaluated postoperatively and at euthanasia for migration of the femoral component and bone resorption. Histologic sections were evaluated semiquantitatively for changes in cell types and numbers, and bone reactions; and quantitatively for size of interface membrane and new bone formation. RESULTS: Radiographically, there tended to be an increase in bone resorption and periosteal bone formation throughout the femoral shaft in Group II compared with Group I, but this was only statistically significant at the region of the femoral neck (R5) at both time periods (P<.05). Semiquantitative histologic evaluation revealed significant increases (P<.05) in cellularity, numbers of fibroblasts, giant cells, macrophages, and mononuclear cells, in Group II primarily at 2 months after surgery. This was also true for interface membrane formation and bone remodeling. Quantitative data showed an increased in the size of the interface membrane and area of bone formation at 8.5 months in Group II. CONCLUSIONS: The cement defect model offered controlled and repeatable production of an interface membrane. The results suggest that a primary cement mantle defect could be a possible trigger for implant instability, eliciting a cascade of biomechanical and molecular events in bone tissue leading to aseptic loosening. CLINICAL RELEVANCE: The results show the effect of defects in the cement mantle in promoting interface membrane formation. Long-term and biochemical studies are required to evaluate the relevance of this interface membrane formation.

A mechanical comparison of 4.5 mm narrow and 3.5 mm broad plating systems for stabilization of gapped fracture models.

OBJECTIVE: To evaluate and compare the mechanical properties of 4.5 narrow and 3.5 broad plating systems using their respective cortical and cancellous screws in unstable, central, and eccentric gap fracture models. STUDY DESIGN: Mechanical evaluation and comparison of 2 dynamic compression plate (DCP) systems. SAMPLE POPULATION: Eighteen cortical and 30 cancellous gapped fracture models. METHODS: DCP (4.5 mm narrow, 3.5 mm broad) with their respective cortical screws were applied to cortical bone density polyurethane foam blocks to construct center gap cortical fracture models that were tested in gap closing monotonic 4-point bending. DCP (4.5 mm narrow, 3.5 mm broad) with their respective cancellous screws were applied to cancellous bone density polyurethane foam blocks to construct eccentric gap cancellous fracture models. The cancellous constructs were tested in monotonic gap opening and gap closing cantilever bending and in cyclic axial loading. Univariate and multivariate repeated measures ANOVA were used to compare the maximum loads at failure of the 4.5 mm constructs and 3.5 mm constructs. RESULTS: The 4.5 mm narrow plating system withstood significantly higher loads at failure than the 3.5 mm broad plating system in 4-point bending (P<.0001) and gap opening cantilever bending (P<.0001). The 4.5 mm system failed in gap closing cantilever bending by plastic deformation of the plate, whereas the 3.5 mm system failed by screw pullout. There was no difference between the 2 systems in cyclic axial loading. CONCLUSION: Results indicate that the 4.5 mm narrow plating system has a mechanical advantage over the 3.5 mm broad plating system for stabilization of gapped fracture models. CLINICAL RELEVANCE: The 4.5 mm narrow plating system may be mechanically advantageous compared with the 3.5 mm broad plating system for stabilizing unreconstructed comminuted long bone fractures in large dogs.

Effect of cisplatin on bone transport osteogenesis in dogs.

OBJECTIVE: To document effects of cisplatin on regenerate bone formation during the distraction and consolidation phases of bone transport osteogenesis. ANIMALS: 10 skeletally mature hounds. PROCEDURES: Bone transport osteogenesis was performed to reconstruct a 3-cm defect in the radius of each dog. Five dogs were randomly selected to receive cisplatin (70 mg/m2, IV, q 21 d for 4 cycles), and 5 were administered saline (0.9% NaCl) solution. Bone mineral density was measured by use of dual-energy x-ray absorptiometry (DEXA) on days 24, 55, and 90 after surgery. Dogs were euthanatized 90 days after surgery. Histomorphometry was performed on nondecalcified sections of regenerate bone. Bone mineral density and histomorphometric indices of newly formed bone were compared between groups. RESULTS: Densitometric differences in regenerate bone mineral density were not detected between groups at any time period. Cisplatin-treated dogs had decreased mineralized bone volume, decreased percentage of woven bone volume, decreased percentage of osteoblast-covered bone, increased porosity, and increased percentage of osteoblast-covered surfaces, compared with values for control dogs. Lamellar bone volume and osteoid volume did not differ significantly between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Regenerate bone will form and remodel during administration of cisplatin. Results of histomorphometric analysis suggest that bone formation and resorption may be uncoupled in cisplatin-treated regenerate bone as a result of increased osteoclast activity or delayed secondary bone formation during remodeling. These histomorphometric differences were modest in magnitude and did not result in clinically observable complications or decreased bone mineral density as measured by use of DEXA.