Frank Gottschalk

The Effects of Twelve Weeks of Bed Rest on Bone Histology, Biochemical Markers of Bone Turnover, and Calcium Homeostasis in Eleven Normal Subjects

This study was undertaken to examine the effects of 12 weeks of skeletal unloading on parameters of calcium homeostasis, calcitropic hormones, bone histology, and biochemical markers of bone turnover in 11 normal subjects (9 men, 2 women; 34 ± 11 years of age). Following an ambulatory control evaluation, all subjects underwent 12 weeks of bed rest. An additional metabolic evaluation was performed after 12 days of reambulation. Bone mineral density declined at the spine (−2.9%, p = 0.092) and at the hip (−3.8%, p = 0.002 for the trochanter). Bed rest prompted a rapid, sustained, significant increase in urinary calcium and phosphorus as well as a significant increase in serum calcium. Urinary calcium increased from a pre‐bed rest value of 5.3 mmol/day to values as high as 7.3 mmol/day during bed rest. Immunoreactive parathyroid hormone and serum 1,25‐dihydroxyvitamin D declined significantly during bed rest, although the mean values remained within normal limits. Significant changes in bone histology included a suppression of osteoblastic surface for cancellous bone (3.1 ± 1.3% to 1.9 ± 1.5%, p = 0.0142) and increased bone resorption for both cancellous and cortical bone. Cortical eroded surface increased from 3.5 ± 1.1% to 7.3 ± 4.0% (p = 0.018) as did active osteoclastic surface (0.2 ± 0.3% to 0.7 ± 0.7%, p = 0.021). Cancellous eroded surface increased from 2.1 ± 1.1% to 4.7 ± 2.2% (p = 0.002), while mean active osteoclastic surface doubled (0.2 ± 0.2% to 0.4 ± 0.3%, p = 0.020). Serum biochemical markers of bone formation (osteocalcin, bone‐specific alkaline phosphatase, and type I procollagen extension peptide) did not change significantly during bed rest. Urinary biochemical markers of bone resorption (hydroxyproline, deoxypyridinoline, and N‐telopeptide of type I collagen) as well as a serum marker of bone resorption (type I collagen carboxytelopeptide) all demonstrated significant increases during bed rest which declined toward normal during reambulation. Thus, under the conditions of this study, the human skeleton appears to respond to unloading by a rapid and sustained increase in bone resorption and a more subtle decrease in bone formation.

Impaired bone formation in male idiopathic osteoporosis: Further reduction in the presence of concomitant hypercalciuria

We present iliac bone histomorphometric data and related biochemical data from 16 nonalcoholic men (50±11 (SD) years) referred for evaluation of spontaneous skeletal and/or appendicular fractures and reduced spinal bone density. All men were eugonadal and had no known underlying disorder associated with osteopenia. For the group, mean serum chemistry values were within normal limits including immunoreactive parathyroid hormone, osteocalcin and serum 1,25-dihydroxyvitamin D [1,25(OH)2D]. Nine men demonstrated hypercalciuria (⩾0.1 mmol/kg per day) while on a constant metabolic diet of 20 mmol/day Ca. Their 24-hour urinary calcium was significantly greater than that for the remaining 7 men (7.4±1.6 vs. 5.0±0.8 mmol/day,p=0.003), as was their calciuric response to a 1 g oral calcium load (0.23±0.06 vs. 0.15±0.05 Ca/creatinine,p=0.042). Serum parameters (including parathyroid hormone and 1,25(OH)2D) of hypercal-ciuric and normocalciuric men were not significantly different. Histomorphometric indices for cancellous bone demonstrated significant differences between the entire group of osteoporotic men and age-adjusted normal values for bone volume (11.4±4.0% vs. 23.2±4.4%), osteoid surface (5.6±3.9% vs. 12.1±4.6%), osteoblastic surface (2.0±2.3% vs. 3.9±1.9%), and mineralizing surface (1.9±2.4% vs. 5.1±2.7%);there were also significant differences in bone formation rate (total surface referent) (0.004±0.001 vs. 0.011±0.006 mm3/mm2 per year). Compared with the normocalciuric group the 9 hypercalciuric men had significantly lower osteoblastic surfaces (1.6±1.9% vs. 2.5±2.6%) and mineralizing surfaces (1.4±1.5% vs. 2.7±3.2%). Cortical bone indices demonstrated a similar trend in formation parameters although these differences did not reach significance. These results suggest that idiopathic osteoporosis in men is characterized by suppressed bone formation due to reduced osteoblast proliferation and that this defect is exaggerated in hypercalciuric men as opposed to normocalciuric men. The cause for suppressed bone formation and increased intestinal absorption of calcium in some men is not known but may be the result of 1,25(OH)2D or some previously unrecognized factor(s).

Transfemoral amputation. Biomechanics and surgery.

The technique of transfemoral amputation has evolved during the last decade whereby muscle stabilization and biomechanical principles have gained new significance. Maintenance of the femoral shaft axis close to normal can be achieved by preservation of the adductor magnus and by myodesis of the muscle to the residual femur. By following established biomechanical principles, and satisfactory surgical techniques, patients undergoing transfemoral amputation are easier to fit with a prosthesis and more likely to remain able to ambulate. Reduction in stump problems can be achieved, and improvement in stump strength is seen.

Controversies in lower extremity amputation.

Using the experience gained from taking care of World War II veterans with amputations, Ernest Burgess taught that amputation surgery is reconstructive surgery. It is the first step in the rehabilitation process for patients with an amputation and should be thought of in this way. An amputation is often a more appropriate option than limb salvage, irrespective of the underlying cause. The decision making and selection of the amputation level must be based on realistic expectations with regard to functional outcome and must be adapted to both the disease process being treated and the unique needs of the patient. Sometimes the amputation is done as a life-saving procedure in a patient who is not expected to walk, but more often it is done for a patient who should be able to return to a full, active life. When considering amputation, the physician should establish reasonable goals when confronted with the question of limb salvage versus amputation, understand the roles of the soft-tissue envelope and osseous platform in the creation of a residual limb, understand the method of weight bearing within a prosthetic socket, and determine whether a bone bridge is a positive addition to a transtibial amputation.

Pre and post-amputation mobility of trans-tibial amputees: Correlation to medical problems, age and mortality

This retrospective study compares pre and post-amputation mobility and the influence of age and associated medical problems. Data from the charts of 120 male patients who underwent unilateral trans-tibial (below-knee) amputation at the Dallas Veterans Administration Hospital between June, 1983 and October, 1991, were collected and analyzed. Mobility was assessed with a six level scale developed by Volpicelli et al. (1983). The presence of cardiac disease, pulmonary disease (COPD), peripheral vascular disease (PVD), diabetes mellitus, degenerative joint disease, blindness, cerebral vascular accident (CVA), and age are correlated with changes in mobility after amputation. Older patients had more medical problems and lower post-amputation scores. Individual medical problems did not influence mobility scores, but the presence of COPD and PVD lowered pre-amputation mobility scores. Cardiac disease and diabetes mellitus influenced post-amputation mobility scores by lowering them, either together or individually. Regardless of age, however, patients with more medical problems were poor ambulators. The cause of amputation per se did not influence mobility scores.

Health-related quality of life in patients with transtibial amputation and reconstruction with bone bridging of the distal tibia and fibula.

Background: Bone-bridging (arthrodesis of the distal tibia and fibula) at the time of transtibial amputation is a controversial operative technique that is anecdotally reported to improve the weightbearing capacity of the residual limb and to decrease residual limb discomfort. Methods: Thirty-two consecutive patients with multiple diagnoses had transtibial amputation with a distal tibial-fibular bone-bridge, all done by a single surgeon (MAP). At an average of 16.3 months after surgery all patients completed the Prosthetics Evaluation Questionnaire (PEQ), a validated outcomes instrument specifically created to evaluate quality of life and functional demands in patients with a lower extremity amputations. Their responses were compared with those of 17 preselected, highly functional transtibial amputees from two academic medical centers who previously had transtibial amputations using a traditional non bone-bridge operative technique; their time since amputation averaged 14.7 years. Results: The “nonselected” consecutive patients with a bone-bridged residual limb scored higher (more favorable) in the Ambulation (p = 0.037) and Frustration (p < 0.001) domains of the PEQ and lower (less favorable) in the Appearance (p = 0.025) subscale. Their scores were similar in the other six domains. Conclusions: Patients of multiple ages with multiple diagnoses who had bone-bridging of the distal tibia and fibula at the time of transtibial amputation had scores on a validated outcomes instrument that were better than or comparable to those of a selected group of highly functional transtibial amputees. The results of this study suggest that bone-bridging at the time of transtibial amputation may enhance patient-perceived functional outcomes.

Aerobic training exercises for individuals who had amputation of the lower limb.

The findings in ten subjects who had an amputation of the lower limb or limbs were studied before and after a fifteen-week aerobic conditioning program to determine if it improved cardiovascular fitness and reduced the effort of walking. Each subject exercised on an Air-Dyne ergometer (Schwinn, Chicago, Illinois) regularly during each week of the study period at 60 to 80 per cent of their estimated maximum heart rate. A test of maximum exercise on the ergometer and a test of walking on a treadmill were administered before and after training. After training, there was an increase of 25 per cent in the maximum capacity for exercise on the ergometer as well as significantly lower values for heart rate and consumption of oxygen during submaximum walking on the treadmill at various inclined grades. Aerobic conditioning was shown not only to improve cardiovascular fitness but also to increase the economy of walking in the subject who had an amputation of the lower limb or limbs.

Effect of slow-release sodium fluoride on cancellous bone histology and connectivity in osteoporosis

We have previously demonstrated that a treatment regimen of slow-release sodium fluoride (SRNaF) and continuous calcium citrate increases lumbar bone mass, improves cancellous bone material quality, and significantly reduces vertebral fracture rate in osteoporotic patients. In order to assess whether such treatment also improves trabecular structure, we quantitated cancellous bone connectivity before and following 2 years of therapy with SRNaF in 23 patients with osteoporosis and vertebral fractures. In addition, we performed bone histomorphometry on the same sections used for connectivity measurements. There was a significant increase in L2-L4 bone mineral density during therapy (0.827 +/- 0.176 g/cm2 SD to 0.872 +/- 0.166, p = 0.0004). Significant histomorphometric changes were represented by increases in mineral apposition rate (0.6 +/- 0.4 microns/d to 1.1 +/- 0.7, p = 0.0078) and adjusted apposition rate (0.4 +/- 0.3 microns/d to 0.6 +/- 0.4, p = 0.016). On the other hand, trabecular spacing significantly declined (from 1375 +/- 878 microns to 1052 +/- 541, p = 0.05). Two-dimensional quantitation of trabecular struts on iliac crest histological sections disclosed significant increases in mean node number per mm2 of cancellous tissue area (0.22 +/- 0.12 vs. 0.39 +/- 0.27, p = 0.0077), the mean node to free-end ratio (0.23 +/- 0.21 vs. 0.41 +/- 0.46, p < 0.05), and in the mean node to node strut length per mm2 of cancellous area (0.098 +/- 0.101 vs. 0.212 +/- 0.183, p < 0.01). There were no significant changes in any of the measurements associated with free-end number or free-end to free-end strut length.(ABSTRACT TRUNCATED AT 250 WORDS)

Does Socket Configuration Influence the Position of the Femur in Above-knee Amputation?

Does Socket Configuration Influence the Position of the Femur in Above-Knee Amputation? Frank Gottschalk;Sohrab Kourosh;Melvin Stills;Bruce McClellan;Jim Roberts; JPO Journal of Prosthetics and Orthotics

The biomechanics of trans-femoral amputation

The biomechanics of trans-femoral amputations has not been previously described. Little attention has been paid to the importance of adductor magnus in holding the femur in its normal anatomical axis. Loss of function of adductor magnus leads to abduction of the residual femur, in a trans-femoral amputation. A cadaver study of the adductor group of thigh muscles has been done and the biomechanical importance of these muscles is documented. The moment arms of the three adductor muscles have been determined, based on muscle attachments and muscle size, relative to each other. Adductor magnus has a major mechanical advantage in holding the thigh in its normal anatomical position. Loss of the distal third of its attachment results in a 70% loss of the effective moment arm of the muscle, which contributes to the abducted femur in standard trans-femoral amputations. A muscle preserving trans-femoral amputation, which keeps adductor magnus intact, prevents abduction of the residual femur and may allow for easier walking with a prosthesis. The conflicting reports about adductor magnus activity during the gait cycle can be explained by this muscles dual innervation by the sciatic and obturator nerves and its dual function as a hip adductor and extensor.