An Evaluation of the Significance of Work-Related Influence Factors on Fitness and the Development of Medical and Orthopaedic Conditions in Military Executives.

Occupational health promotion is an effective tool to improve the state of health of employees. As part of occupational health promotion in the German Bundeswehr, top-ranking military executives are offered a medical examination and training programme. Health-related data is collected as a basis for training and lifestyle counselling. This data was subjected to a retrospective evaluation in order to identify occupational risk factors and their correlation with cardiovascular resilience, trunk strength, and the development of orthopaedic and internal disorders. A total of 122 military executives (all male, age 54.6 ± 4.2 years) answered a questionnaire aimed at evaluating private and occupational stress factors. The medical history was followed by a medical and orthopaedic examination involving a lactate performance test (treadmill or bicycle ergometry) and an isometric trunk strength measurement. The data obtained was then statistically evaluated. For military executives, work-related travelling and commuting involve a high risk of medical and orthopaedic conditions. Regular exercise leads to improved fitness levels. In order to prevent medical problems, military executives working long hours should regularly take part in fitness and weight training under professional instructions.

The effect of continuous passive motion and sling exercise training on clinical and functional outcomes following total knee arthroplasty: a randomized active-controlled clinical study.

BACKGROUND: The parallel-group randomized active-controlled clinical study was conducted to compare the effectiveness of two in-hospital range of motion (ROM) exercise programs following total knee arthroplasty (TKA). Continuous passive motion (CPM) is frequently used to increase ROM and improve postoperative recovery despite little conclusive scientific evidence. In contrast, a new active sling-based ROM therapy requires the activation of the knee joint muscles and dynamic joint stabilization. It was hypothesized that higher demands on muscle strength and muscle coordination during sling exercise training (ST) might be advantageous for early recovery following TKA. METHODS: A total of 125 patients undergoing primary TKA were assessed for eligibility. Thirty-eight patients were randomly assigned to receive ST or CPM (control intervention) during hospital stay. Patients were assessed before TKA for baseline measurement (pretest), 1 day before discharge (posttest) and 3 months after TKA (follow-up). The passive knee flexion range of motion (pFL) was the primary outcome measure. Secondary outcome measures included active knee flexion range of motion, active and passive knee extension ROM, static postural control, physical activity, pain, length of hospital stay as well as clinical, functional and quality-of-life outcomes (SF-36, HSS and WOMAC scores). Data were analyzed according to the intention-to-treat principle. Differences between the groups were tested for significance by the unpaired Student's t test or an analysis of covariance (ANCOVA) adjusted for baseline, weight, sex, age, pain and physical activity. RESULTS: A between-group difference could be determined at posttest. The pFL was significantly higher by 6.0° (95% CI 0.9 to 11.2°; P = 0.022) in the ST group. No difference between groups in pFL was documented at follow-up. Furthermore, no significant differences could be observed for any secondary outcome measure at posttest and follow-up. CONCLUSIONS: ST seems to have a clinically relevant beneficial short-term effect on pFL compared to CPM. The results support the implementation of ST in rehabilitation programs following TKA. LEVEL OF EVIDENCE: Therapy, level 2b.

Treatment of medial tibial stress syndrome according to the fascial distortion model: a prospective case control study.

Medial tibial stress syndrome (MTSS) is a common problem among athletes and soldiers. There is no proven theory that could explain the pathophysiology of shin splints. The therapies described so far are time-consuming and involve a high risk of relapse. The method according to the fascial distortion model (FDM) addresses local changes in the area of the lower leg fascia. It is suited to reduce pain and functional impairments associated with this symptom complex by applying targeted manual techniques. 32 patients (male: 30; female: 2) participated in this study. Visual analogue scale (VAS) was used for the quantification of pain. Scores were also given to rate the maximum painless exercise tolerance of the patients. Subsequently treatment of the crural fascia was performed. Patients retested ability of running and jumping. Therapy was continued until full exercise tolerance or painlessness was reached. A significant reduction of the VAS pain score from 5.2 to 1.1 could be achieved (P < 0.001). The impairment of exercise tolerance could be reduced from 7 to 2 points (P < 0.001). The duration of treatment was 6.3 (SD: 4.3) days on average. The FDM therapy is a potential effective method for acute treatment of MTSS.

Effects of wearing different personal equipment on force distribution at the plantar surface of the foot.

BACKGROUND: The wearing of personal equipment can cause specific changes in muscle activity and posture. In the present study, we investigated the influence of differences in equipment related weight loading and load distribution on plantar pressure. In addition, we studied functional effects of wearing different equipment with a particular focus on relevant changes in foot shape. METHODS: Static and dynamic pedobarography were performed on 31 male soldiers carrying increasing weights consisting of different items of equipment. RESULTS: The pressure acting on the plantar surface of the foot increased with higher loading, both under static and dynamic conditions (p < 0.05). We observed an increase in the contact area (p < 0.05) and an influence of load distribution through different ways to carry the rifle. CONCLUSIONS: The wearing of heavier weights leads to an increase in plantar pressure and contact area. This may be caused by flattening of the transverse and longitudinal arches. The effects are more evident in subjects with flat feet deformities which seem to flatten at an earlier load condition with a greater amount compared to subjects with normal arches. Improving load distribution should be a main goal in the development of military equipment in order to prevent injuries or functional disorders of the lower extremity.

The effect of the weight of equipment on muscle activity of the lower extremity in soldiers.

Due to their profession and the tasks it entails, soldiers are exposed to high levels of physical activity and strain. This can result in overexertion and pain in the locomotor system, partly caused by carrying items of equipment. The aim of this study was to analyse the extent of muscle activity in the lower extremities caused by carrying specific items of equipment. For this purpose, the activity of selected groups of muscles caused by different items of equipment (helmet, carrying strap, backpack, and rifle) in the upper and lower leg was measured by recording dynamic surface electromyograms. Electrogoniometers were also used to measure the angle of the knee over the entire gait cycle. In addition to measuring muscle activity, the study also aimed to determine out what influence increasing weight load has on the range of motion (ROM) of the knee joint during walking. The activity of recorded muscles of the lower extremity, that is, the tibialis anterior, peroneus longus, gastrocnemius lateralis, gastrocnemius medialis, rectus femoris, and biceps femoris, was found to depend on the weight of the items of equipment. There was no evidence, however, that items of equipment weighing a maximum of 34% of their carrier's body weight had an effect on the ROM of the knee joint.

Cementless total hip replacement: a prospective clinical study of the early functional and radiological outcomes of three different hip stems.

INTRODUCTION: Optimal fixation of cementless total hip stems is essential for long-term survival rates. AIM: The purpose of this prospective study was to evaluate the early clinical and radiological outcomes of two new total hip stems with metaphyseal (Symax®) and predominantly diaphyseal (Hipstar®) anchoring principles in comparison to the well-established straight Zweymueller (SL-Plus®) stem. METHOD: Clinical and radiological evaluations of 74 patients were undertaken preoperatively as well as at 6 and 12 months postoperatively using the Harris Hip Score (HHS) and Western Ontario and McMaster Universities-Score. RESULTS: During follow-up no stem had to be revised. The mean preoperative HHS of the three study groups amounted to 54.6 ± 15.7 points. At the 12 months follow-up the mean HHS in the SL-Plus group (n = 22) was 88.3 ± 10.5 points, in the Hipstar group (n = 25) 83.3 ± 15.0 and the in Symax group (n = 27) 83.6 ± 15.1. Due to stress shielding the straight Hipstar stem revealed radiolucent lines in the proximal Gruen zones of about 60%, whereas the SL-Plus stem showed significantly more radiolucent lines (87%). However, subsequent long-term studies must be carried out in order to clarify if the progression of radiolucent lines may influence the clinical result and implant longevity.

Influence of Training of Orthopaedic Surgeons on Clinical Outcome after Total Hip Arthroplasty in a High Volume Endoprosthetic Centre. / Einfluss des sich in Weiterbildung befindlichen Operateurs auf die postoperative Ergebnisqualität nach hüftendoprothetischer Versorgung in einem EndoProthetikZentrum der Maximalversorgung.

BACKGROUND: The study aims to evaluate whether the postoperative outcome and the probability of complications of patients with total hip arthroplasty increases significantly when surgeons in training are in charge, assisted by a high volume surgeon, compared to a highly experienced orthopaedic surgeon, within the context of a high volume hospital certified to EndoCert. MATERIAL AND METHODS: 192 patients with a primary hip arthroplasty were included. To assess the outcome, the Harris Hip Score, WOMAC, SF-36 and EuroQol-5D were surveyed pre- and 12 months postoperatively. As complications we considered the quality indicators defined by EndoCert. RESULTS: We found significant improvements in the postoperative score values with the qualifications of the surgeon in charge, even when a high volume surgeon or a surgeon in training was responsible. If a surgeon in training is assisted by a highly experienced surgeon, the risk of complications does not increase, although the operating time was significantly increased. CONCLUSION: Both the surgeon in training as well as the arthroplasty patient benefit from implementing the EndoCert system, because the postoperative outcome and the complication probability is independent of the qualifcation of the operating orthopaedic surgeon performing total hip arthroplasty when assisted by an experienced surgeon.

Adhesive strength of total knee endoprostheses to bone cement - analysis of metallic and ceramic femoral components under worst-case conditions.

Evaluation of the adhesive strength of femoral components to the bone cement is a relevant parameter for predicting implant safety. In the present experimental study, three types of cemented femoral components (metallic, ceramic and silica/silane-layered ceramic) of the bicondylar Multigen Plus knee system, implanted on composite femora were analysed. A pull-off test with the femoral components was performed after different load and several cementing conditions (four groups and n=3 components of each metallic, ceramic and silica/silane-layered ceramic in each group). Pull-off forces were comparable for the metallic and the silica/silane-layered ceramic femoral components (mean 4769 N and 4298 N) under standard test condition, whereas uncoated ceramic femoral components showed reduced pull-off forces (mean 2322 N). Loading under worst-case conditions led to decreased adhesive strength by loosening of the interface implant and bone cement using uncoated metallic and ceramic femoral components, respectively. Silica/silane-coated ceramic components were stably fixed even under worst-case conditions. Loading under high flexion angles can induce interfacial tensile stress, which could promote early implant loosening. In conclusion, a silica/silane-coating layer on the femoral component increased their adhesive strength to bone cement. Thicker cement mantles (>2 mm) reduce adhesive strength of the femoral component and can increase the risk of cement break-off.

Prospective comparative clinical study of ceramic and metallic femoral components for total knee arthroplasty over a five-year follow-up period.

BACKGROUND: The aim of this prospective comparative study was to evaluate the clinical and radiological outcomes of a TKA system, comparing a ceramic (BIOLOX® delta) and metallic (Co28Cr6Mo) femoral component over a five-year follow-up period. METHODS: Forty-three TKA patients (17 metallic and 26 ceramic femoral components) were enrolled in the study. Clinical and radiological evaluations were performed preoperatively and at three, 12, 24 and 60months postoperatively, using the HSS-, WOMAC- and SF36-Scores, in addition to standardized X-rays. RESULTS: The HSS-Score improved significantly from 58.7±12.7 points preoperatively to 88.5±12.3 points at five-years postoperative in the ceramic group, and 60.8±7.7 to 86.2±9.4 points in the metallic group. WOMAC- and SF-36-Scores showed significant improvement over time in both groups. There were no significant differences between groups for HSS-, WOMAC- and SF-36-Scores, nor for range of motion (p≤0.897) at any follow-up evaluation. Furthermore, radiological evaluation showed no implant loosening or migration in either group. CONCLUSIONS: Mid-term outcomes for the ceramic femoral components demonstrated good clinical and radiological results, as well as comparable survivorship to the metallic femoral component of the same total knee system, and to other commonly used metallic total knee systems. Therefore, ceramic knee implants may be a promising solution for the population of patients with osteoarthritis and metal sensitivity. Long-term studies are required in order to confirm the positive mid-term clinical results, and to follow the implant survival rate in regard to the enhanced wear resistance of ceramic implants.

Importance of a distal centralizer in experimental malpositioning of cemented stems. A biomechanical study on human femora.

INTRODUCTION: Femoral centralizers in total hip arthroplasty (THA) are designed to improve the neutral implant position and ensure a homogeneous cement mantle without implant-bone impingement. To date there are no data about the cement mantle configuration and implant position after malinsertion, as seen in mini-open approaches or adipose patients with a limited view. The present biomechanical study was performed to investigate whether a distal centralizer may correct and optimize the position of a malinserted femoral stem. MATERIAL AND METHODS: Thirteen MS 30 stems with and without a distal centralizer each were implanted in paired fresh human femora. Malinsertion was performed using a 3D guiding device with 10° deviation to the femoral axis in the sagittal plane. The thickness of the cement mantle was measured on the anterior, posterior, medial and lateral side of the implanted stem at a distance of 1 cm each. For each side data were taken at 13 points. RESULTS: Digital evaluation of the cement mantle thickness revealed compareable values in frontal plane when a centralizer was used (p > 0.4). In contrast the cement mantle thicknesses without a centralizing device varied in the distal region between 3.38 mm and 5.09 mm (p ≤ 0.001) and in the central region between 3.52 mm and 4.19 mm (p ≤ 0.009). CONCLUSIONS: A distal centralizer allows a more uniform cement mantle and neutral alignment even with a malinsertion of the femoral stem. This could reduce the failure rate and early loosening in complex THA.

Postoperative development of bone mineral density and muscle strength in the lower limb after cemented and uncemented total hip replacement.

BACKGROUND: Numerous studies have shown reduction of periprosthetic bone mineral density (BMD) after hip replacement. The effect on the whole limb, however, is still unexplored. This study's objective was to analyse the postoperative development of BMD and muscle strength of the limb after total hip replacement (THR) and to determine links between these parameters. METHODS: 55 patients, who underwent THR, were included. Depending on therapeutic indication, either an uncemented stem (Group A, n=30) or a cemented stem (Group B, n=25) has been implanted. In the limbs, the measurement of BMD using DEXA and the maximum isometric muscle strength, detected by a leg press, were undertaken preoperatively and after 3, 6 and 12 months. RESULTS: A total of 12 patients (Group A: n = 6, Group B: n = 6) were excluded due to reasons which were not relevant to the study. So, the results refer to the data of 43 patients. In Group A (uncemented, n = 24), a significant decrease of BMD on the operated extremity was seen after 3, 6 and 12 months compared with preoperative values. Isometric muscle strength on the affected extremity increased significantly after 6 and 12 months. In Group B (cemented, n = 19), with a lower baseline compared to group A, an increase in BMD of the affected limb was seen postoperatively. This rise was significant after 12 months. With regard to the isometric muscle strength, a significant increase could be observed in this group after 6 and 12 months. CONCLUSION: Analogous to postoperative reduction of periprosthetic bone density, a decrease of the entire limb BMD on the operated leg occurred after implantation of uncemented hip stems. In contrast, an increase in BMD was recorded for cemented stems. Regardless of the type of anchoring, a substantial increase in muscular strength could be observed postoperatively in both groups.

Influence of footwear and equipment on stride length and range of motion of ankle, knee and hip joint.

PURPOSE: Footwear and equipment worn by military personnel is of importance for them to be able to meet the physical demands specific to their profession daily activities. The aim of the present study was to investigate by means of gait analysis how army-provided footwear and equipment influence the range of motion of hip, knee and ankle joints as well as stride length. METHODS: Thirty-two soldiers were subjected to gait analysis on a treadmill by way of video recordings and goniometric measurements. RESULTS: The stride length increased when military shoes are worn. We found no influence on stride length in connection to increased loading. The weight of the shoes represents the decisive factor. Neither shoes nor equipment changed the range of motion of the knee joint. Weight of equipment affected range of motion of the hip joint. The range of motion of the upper and lower ankle joints was mainly influenced by the properties of the shoes. CONCLUSIONS: Military footwear and weight of equipment influence stride length and range of motion of joints of the lower extremities in a specific way. Shape of material is the decisive factor.

Biomechanical study of the influence of the weight of equipment on selected trunk muscles.

Overexertion and pain of the musculoskeletal system may occur partly owing to load application by the equipment. Both the weight of equipment and the duration of loading are relevant. The aim of the present study was to examine the extent of loading and resultant strain in the trunk muscles. Therefore, the trunk posture of soldiers and muscular activity in reaction to different equipment components (helmet, load-carrying equipment, gun and backpack) were evaluated. Electromyography was performed and a visual assessment of body axis was conducted based on standardised planar images. Data indicate that the activity of the trunk muscles examined (latissimus dorsi, trapezius and pectoralis major) is dependent on the weight and distribution of the equipment components. Activity in the trapezius muscle, for instance, was doubled during specific load application. Moreover, the method of carrying the rifle had a significant influence on the activity of the trapezius muscle (one-sided decrease of activity by 50%). Subjects were able to stabilise the body axis in the coronal plane through increased muscle activity, however, in the sagittal plane a compensatory ventral inclination of the body was observed. Uneven load distribution can lead to an irregular strain on the musculoskeletal system.

Comparative Study of Clinical and Radiological Outcomes of Unconstrained Bicondylar Total Knee Endoprostheses with Anti-allergic Coating.

BACKGROUND: Hypersensitivity reactions to implant materials have become more important in total knee replacement (TKR). The purpose of this retrospective comparative study was to evaluate the clinical and radiological outcomes of unconstrained bicondylar total knee prostheses with and without anti-allergic titanium(niobium)nitrite (Ti(Nb)N) coating. METHODS: Twenty-four patients (25 TKRs) underwent a preoperative clinical evaluation and then a postoperative evaluation after 26.2 months in the allergy group treated with coated implants (n=13 implants) and after 24.5 months in the control group treated with uncoated implants but identical geometry (n=12) using HSS, WOMAC and SF-36 scores. Radiological evaluations were performed using standard anterior-posterior (a.p.) and lateral X-rays. RESULTS: During follow-up two patients of the allergy group had to undergo revision surgery due to non-implant-related reasons. A comparative analysis of both study groups showed a significant difference in the HSS scores at both evaluation time points (MW test p≤0.050); these findings are remarkable since the control group had a significantly lower score preoperatively (54.0 vs 65.0 points) and a significantly higher score (82.5 vs 75.0 points) postoperatively. The preoperative and postoperative WOMAC and SF-36 scores were comparable in both groups (MW test p≥0.052), although the postoperative increase in the score for the allergy group was lower. The radiological results were comparable in both groups and were unlikely to influence the results. CONCLUSIONS: This clinical study demonstrates the restricted outcome in postoperative function and quality of life in the allergy group compared to the control group.

The influence in airforce soldiers through wearing certain types of army-issue footwear on muscle activity in the lower extremities.

The objective of the study was to analyse the influence of the shape and material of the military footwear worn by soldiers on muscle activity in the lower extremities, and whether such footwear could explain specific strain complaints and traumatic lesions in the region of the lower extremities.37 soldiers (one woman, 36 men) aged between 20 and 53 years underwent a dynamic electromyography (EMG) analysis. Wearing - one pair at a time - five different types of shoes, the subjects were asked to walk on a treadmill, where an EMG of the following muscles was taken: M. tibialis anterior, M. gastrocnemius mediales, M. gastrocnemius laterales, M. peroneus longus and M. rectus femoris.When the subjects wore old-fashioned outdoor jogging shoes increased muscle activity was observed in the region of the M. peroneus longus. This can be interpreted as a sign of the upper ankle joint requiring increased support and thus explain the higher susceptibility to sprains experienced in connection with these shoes. When the subjects wore combat boots, increased activity was observed in the region of the Mm. tibialis anterior and rectus femoris. The specific activity differences that were observed in particular muscles may have influence in the occurrence of certain disorders, especially in untrained recruits. This can be linked to various strain-related disorders such as shin splints and patellofemoral pain. The data obtained using EMG can provide information about the likelihood of a clustering of the complaints experienced by soldiers during training or active service.

Impact of preoperative variables on the functional and radiological outcome of an uncemented femoral stem: a prospective two-year follow-up.

The demand for improved clinical outcomes in total hip arthroplasty (THA) has led to improvements in fixation, bone ingrowth and designs providing an increased range of motion.The purpose of this prospective clinical study was to evaluate the outcome of a new cementless stem (Hipstar). The variables of body mass index (BMI), gender, preoperative function and age were explored as predictors for recovery after surgery. Clinical and radiological evaluation of 100 patients were undertaken preoperatively and at 6, 12 and 24 months postoperatively using the Harris Hip Score (HHS), WOMAC-Score and the SF-36-Score. The mean preoperative HHS was 53.6 + or - 14.5 points and it increased significantly to 82.8 + or - 15.4 at the postoperative evaluation at 24 months (WI-test p<0.001). Diminished preoperative function led to a lower postoperative score, but BMI, age and gender were not predictors of clinical and radiological outcome. Due to stress-shielding the straight Hipstar stem revealed radiolucent lines of between 41.5% and 68.5% in the proximal Gruen zones, which indicates a higher primary and secondary stability by enhanced osseous integration compared to other straight stems. Our clinical results are encouraging, but long-term follow-up will be necessary to confirm the successful introduction of the new Hipstar stem.

Impact of preoperative function on early postoperative outcome after total hip arthroplasty.

PURPOSE: To investigate the impact of preoperative functional status on early postoperative outcomes after total hip arthroplasty (THA). METHODS: 39 men and 36 women aged 50 to 76 years who underwent cementless THA for osteoarthritis were followed up for at least 2 years. Patients were evaluated pre- and post-operatively (at 6, 12, and 24 months) using the Harris Hip Score (HHS), 36-item Short Form Health Survey (SF-36), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Patients were classified into 3 groups based on their preoperative HHS (poor, <45; intermediate, 45-55; good, >55). Differences between and within groups were compared. RESULTS: Patients with a poor preoperative HHS had worse early postoperative outcomes in terms of HHS, SF-36, and WOMAC. Postoperative pain and function correlated with preoperative HHS, but postoperative range of motion and deformity did not. CONCLUSION: Poor preoperative function may affect recovery unfavourably and lead to prolonged pain. Earlier THA in the course of functional decline may associate with better outcomes.