Impingement-free range of movement, acetabular component cover and early clinical results comparing 'femur-first' navigation and 'conventional' minimally invasive total hip arthroplasty: a randomised controlled trial.

We report the kinematic and early clinical results of a patient- and observer-blinded randomised controlled trial in which CT scans were used to compare potential impingement-free range of movement (ROM) and acetabular component cover between patients treated with either the navigated 'femur-first' total hip arthroplasty (THA) method (n = 66; male/female 29/37, mean age 62.5 years; 50 to 74) or conventional THA (n = 69; male/female 35/34, mean age 62.9 years; 50 to 75). The Hip Osteoarthritis Outcome Score, the Harris hip score, the Euro-Qol-5D and the Mancuso THA patient expectations score were assessed at six weeks, six months and one year after surgery. A total of 48 of the patients (84%) in the navigated 'femur-first' group and 43 (65%) in the conventional group reached all the desirable potential ROM boundaries without prosthetic impingement for activities of daily living (ADL) in flexion, extension, abduction, adduction and rotation (p = 0.016). Acetabular component cover and surface contact with the host bone were > 87% in both groups. There was a significant difference between the navigated and the conventional groups' Harris hip scores six weeks after surgery (p = 0.010). There were no significant differences with respect to any clinical outcome at six months and one year of follow-up. The navigated 'femur-first' technique improves the potential ROM for ADL without prosthetic impingement, although there was no observed clinical difference between the two treatment groups.

Total hip arthroplasty through the mini-incision (Micro-hip) approach versus the standard transgluteal (Bauer) approach: a prospective, randomised study.

PURPOSE: To compare outcome after total hip arthroplasty (THA) through the mini-incision approach versus the standard transgluteal approach. METHODS: 80 women and 63 men aged 33 to 89 (mean, 62) years with primary osteoarthritis of the hip were randomised to undergo unilateral THA through a mini-incision approach (Micro-hip, n=55) or standard, lateral, transgluteal approach (Bauer, n=88). Levels of haemoglobin, haematocrit, serum creatine kinase, and C-reactive protein, length of hospital stay, mobilisation, and any complication were recorded. Visual analogue scale (VAS) for pain was assessed. Hip function was assessed using the Harris Hip Score and the Oxford Hip Score, whereas general health was assessed using the EQ-5D general health questionnaire. The cup inclination and varus/valgus of the stem position were measured using a goniometer. RESULTS: The Micro-hip group achieved a significantly lower mean incision length (9.3 vs. 13.4 cm, p<0.001), mean surgical time (60 vs. 68 minutes, p=0.021), mean reduction in haemoglobin level (2.1 vs. 2.8 g/dl, p<0.001), and mean VAS for pain from hour 6 to day 6 (all p<0.05). One patient in the Micro-hip group developed early aseptic loosening of the cup and underwent revision surgery at month 4. Three patients in the Bauer group and one patient in the Micro-hip group sustained intra-operative nondisplaced fractures of the proximal femur, which were fixed with cerclages. Two patients in the Microhip group developed deep vein thrombosis during week 1. CONCLUSION: THA through the Micro-hip approach achieved faster pain relief.

[Principles and new concepts in computer-navigated total hip arthroplasty]. / Grundlagen und neue Konzepte in der computernavigierten Hüftendoprothetik.

Combined component placement of cup and stem is closely correlated to stability, functionality and wear in total hip replacement (THA). Computer-navigated orthopedic surgery offers a reliable control method for a complex three-dimensional situation. Imageless navigation systems without the need of preoperative or intraoperative image acquisition and exposure to radiation have been proven to increase the accuracy of positioning the acetabular component and measure intraoperative leg length and offset changes precisely. A new development in this field is the noninvasive external femoral reference marker array system in conjunction with an imageless measurement technique. The future generation of imageless navigation systems will switch from simple measurement tasks to an integral part of the surgical process in navigated THA. The aim will be to find an optimized complementary component orientation with improved postoperative functionality and optimized range of motion without impingement.

[Minimally invasive surgery in total hip arthroplasty : Surgical technique of the future?]. / Minimalinvasive Operationstechniken in der Hüftgelenktotalendoprothetik : Operationstechniken der Zukunft?

AIM: A selective analysis of the latest literature was carried out including prospective clinical controlled studies on the comparison between minimally invasive total hip arthroplasty (MIS) and the conventional technique. METHODS: An online data base search for controlled study designs within the last 3 years (2009-2011) which compared MIS with standard procedures was performed. Data such as operation time, blood loss, Harris hip score, complications and implant positioning were compared. RESULTS: A total of 11 studies which compared the results of 387 MISs and 264 operations on hips with the standard technique were analyzed. In the majority of the studies reduced levels of creatine kinase and myoglobin as well as reduced intraoperative blood loss were reported. In the early postoperative period up to postoperative week 6 significant advantages in the Harris hip score were reported for the MIS patients. Postoperative complications and implant positioning were comparable in both groups. The operation time was significantly longer in the MIS group for some studies. CONCLUSIONS: Minimally invasive techniques in total hip arthroplasty are nowadays no longer seen as just cosmetically attractive but rather as a real improvement for the clinical outcome. In this respect prospective clinically controlled studies within the last 3 years showed advantages in the early postoperative period.

The role of the transverse acetabular ligament for acetabular component orientation in total hip replacement: an analysis of acetabular component position and range of movement using navigation software.

Orientation of the native acetabular plane as defined by the transverse acetabular ligament (TAL) and the posterior labrum was measured intra-operatively using computer-assisted navigation in 39 hips. In order to assess the influence of alignment on impingement, the range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard acetabular component position (abduction 45°/anteversion 15°). With respect to the registration of the plane defined by the TAL and the posterior labrum, there was moderate interobserver agreement (r = 0.64, p < 0.001) and intra-observer reproducibility (r = 0.73, p < 0.001). The mean acetabular component orientation achieved was abduction of 41° (32° to 51°) and anteversion of 18° (-1° to 36°). With respect to the Lewinnek safe zone (abduction 40° ±10°, anteversion 15° ±10°), 35 of the 39 acetabular components were within this zone. However, there was no improvement in the range of movement (p = 0.94) and no significant difference in impingement (p = 0.085). Alignment of the acetabular component with the TAL and the posterior labrum might reduce the variability of acetabular component placement in total hip replacement. However, there is only a moderate interobserver agreement and intra-observer reliability in the alignment of the acetabular component using the TAL and the posterior labrum. No reduction in impingement was found when the acetabular component was aligned with the TAL and the posterior labrum, compared with a standard acetabular component position.

[Femoroacetabular impingement: minimally invasive hip surgery]. / Femoroazetabulares Impingement: Minimalinvasive Hüftchirurgie.

Minimally invasive hip surgery is an innovative surgical technique mainly used in femoroacetabular impingement (FAI). The purpose of the surgical correction in FAI deformity is to eliminate the etiologic factor in the development of the so-called idiopathic hip osteoarthritis. Decisive for the success of joint preservation is the preoperative assessment of the deformity and the possible damage to the cartilage. The optimal intervention in the presence of substantial cartilage damage is joint replacement. The patient's history and the findings of physical examination with detailed radiographs and magnetic resonance imaging based on a sagittal oblique localizer optionally using intra-articular contrast prevent underestimation of the stage of the disease. Knowledge about the options and techniques of minimally invasive hip surgery helps to identify patients appropriate for other interventions like surgical dislocation of the hip and the periacetabular osteotomy.

[Femur first in hip arthroplasty--the concept of combined anteversion]. / Femur first beim Hüftgelenksersatz--Das Konzept der kombinierten Anteversion.

BACKGROUND: The concept of combined anteversion for total hip arthroplasty (THA) proposes a relationship between the cup and stem components that theoretically maximises the postoperative range of motion and minimises the risk for impingement of the joint. Using computer-assisted navigation tools, an anteversion angle of the cup component can be made to be dependent on the antetorsion angle of the stem component (or vice versa). We studied how this functional concept would be different from the traditional cup placement according to the Lewinnek safe zone. PATIENTS AND METHODS: We prospectively reviewed 42 patients (42 hips) who underwent imageless, computer-assisted THA with cementless implants due to osteoarthritis between May and October 2008. Using computer navigation, we determined the cup anteversion with optimised containment and measured femoral stem antetorsion. Our goal was to implant the original implants with a combined anteversion of 37 degrees. RESULTS: Mean cup anteversion was 22.5 degrees, mean combined anteversion was 35.2 degrees. Femoral antetorsion ranged from -13 to 38 degrees (mean: 18 degrees). Mean anteversion of the trial cup with optimised containment was 15.9 degrees and therefore close to the recommendation according to the Lewinnek safe zone. The total postoperative range of motion (flexion, extension, abduction, internal/external rotation) as measured with the navigation system intraoperatively was 209 degrees compared to 94 degrees measured clinically preoperatively. No THA dislocation occurred during the test. CONCLUSION: The combined anteversion concept results in a cup position with more anteversion when compared to the traditional cup placement according to the Lewinnek safe zone. In this context, modern navigation techniques open a new frontier for an optimised component position. Placing the cup and stem in relation to the anteversion for both components allows consideration of the patient-specific biomechanics.

[Current state of doing minimal invasive total hip replacement in Germany, the use of new implants and navigation--results of a nation-wide survey]. / Aktueller Stand der minimalinvasiven Hüftendoprothetik in Deutschland, neue Implantate und Navigation--Ergebnisse einer bundesweiten Umfrage.

AIM: Total hip replacement has been developed to a very successful surgical procedure over 3 decades. In the last years many new helpful implants were introduced to the market, minimally invasive procedures were presented together with the technique of navigation. There is no scientific proof of the benefit of these procedures. The objective of this study was to collect data about the preferences of the surgeons for procedures and implants. METHODS: In a countrywide anonymous survey, staff of 240 German trauma surgery and orthopaedic surgery departments were asked about their MIS procedures and their treatment strategies (August 2006). RESULTS: 184 of the questionnaires have been returned representing 64,569 THRs, 65% with cementless fixation, 12.6% with bone conserving implants and 4.1% with resurfacing. We found that 77% of the respondents were doing minimally invasive THR. 34% of all THR are minimally invasive (MIS) procedures, while 23% of the patients ask for MIS. Most of the surgeons (54%) define "minimally invasive" as the preservation of muscle, tendons and soft tissue, and 33% as the length of skin incision to be less than 10 cm. 78% are convinced that long-term survival is achievable even with less invasive methods. The most common MIS approach is the anterior/anterolateral (42%), for the standard procedure (not MIS) the dorsal approach is the most used (42%), and for revision surgery the lateral approach (44%). 77% of the respondents never use navigation and 54% are convinced that there is no sense in it. 75% of MIS surgeons use special MIS instruments: 97% use redon drainage, 48% the cell-saver, 71% of the operations are performed by senior/head surgeons. The assistant quota was largest in high-volume centres. CONCLUSION: Innovative implants are used with care, more than one-third of all implants are still fixed with cement. MIS is performed in one-third of the THRs and it is not driven by sensationalised reports in the media. Even the surgeons' philosophy is oriented by long-term survival, most of them are defining MIS by preventing soft tissue damage and not by the length of skin incision. The transgluteal approach is still widespread, the drawbacks are hardly detectable, the soft tissue damage irreversible. Still lacking an adequate definition of the term "MIS", it is unclear whether the soft tissue is spared or the damage to it is the same under a smaller skin incision. Computer-aided surgery in THR is not used by most of the surgeons, for the majority it is not favourable.

Emergency aortocoronary bypass grafting after failed percutaneous transluminal angioplasty versus elective bypass grafting.

From January 1980 through July 1994 fiftyseven patients underwent emergency coronary bypass grafting (CABG) after unsuccessful percutaneous transluminal angioplasty (PTCA), (Group I). This group was compared with a cohort of 57 patients, who underwent elective coronary bypass grafting (Group II). The 2 groups were compared in the rate of perioperative myocardial infarction, amount of blood loss, rethoracotomy because of bleeding, use of blood units and products, and length of stay in the intensive care unit. The data of both groups were retrospectively analyzed. Significant differences were observed: Perioprative myocardial infarction in group I was 18 patients (31%) versus 2 patients (3%) in group II (p<0.0008). Amount of blood loss was higher (p<0.038), and the use of packed red blood cells was higher too (p<0.000) in group I. The length of stay in the intensive care unit was longer (p<0.000) in group I. Six rethoracotomies (10%) occured in group I versus 0 in group II. There were no hospital mortalities in either groups. We conclude there is a significant increase in morbidity in patients with emergency CABG after failed PTCA than patients who underwent elective CABG.

Fluid therapy with Ringer's solution versus Haemaccel following coronary artery bypass surgery.

BACKGROUND: Crystalloid and colloid infusion can be used in volume therapy following heart surgery. In this prospective, randomised study we compared Ringer's solution (group R) to Haemaccel (group H) following coronary artery bypass grafting. METHODS: A stringent protocol for adjusting the infusion rate was used. Haemodynamic parameters and pulmonary function were evaluated as well as chest tube drainage. The double-indicator dilution method was used to measure total blood volume index (TBVI), intrathoracic blood volume index (ITB-VI) and extravascular lung water index (EVLWI). RESULTS: Haemodynamic stability was achieved in both groups throughout the study period, as judged from mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, and cardiac index. However, the total volume infused was significantly higher in group R. TBVI and ITBV were higher in group H, although only significant at 8 h for TBVI. Pulmonary function was similar in both groups. There was no significant difference in EVLWI, pulmonary shunt fraction, and time on mechanical ventilation. Likewise, chest tube drainage was not significantly different in both groups. CONCLUSION: We conclude that volume therapy with Haemaccel following heart surgery requires less volume and achieves better filling of the circulation compared to Ringer's solution.

Fluid resuscitation with Haemaccel vs. human albumin following coronary artery bypass grafting.

Several colloid preparations are available for fluid resuscitation following heart surgery. We conducted a randomized prospective trial to compare a polygeline infusion versus human albumin with respect to hemodynamic and pulmonary function. 20 patients were randomly assigned to receive either Haemaccel or human albumin using a standardized protocol for the first 8 hours following heart surgery. The double-indicator dilution method was used to measure total blood volume index (TBVI), intrathoracic blood volume index (ITBVI) and extravascular lung water index (EVLWI) three times during the study period. Pulmonary shunt fraction, time on ventilator, and chest tube drainage were measured as well. Hemodynamic stability was achieved in both groups throughout the study period, as judged from mean arterial pressure, pulmonary capillary wedge pressure, and cardiac index. ITBV and TBVI were higher in the albumin group, although only significant at 4 hours for TBVI. There was no significant difference in EVLWI, pulmonary shunt fraction, and time on mechanical ventilation. Likewise, chest tube drainage was not significantly different in both groups. Haemaccel is effective in maintaining hemodynamic stability following heart surgery without ill effects of lung function or chest tube drainage. Treatment costs are substantially lower compared to human albumin.

Cardiovascular and pulmonary effects of aerosolized prostacyclin administration in severe respiratory failure using a ventilator nebulization system.

We investigated the effects of aerosolized prostacyclin (PGI2) administration on hemodynamics and pulmonary gas exchange in 8 patients with severe respiratory failure and acute pulmonary hypertension. Nebulization of epoprostenol (5 ng/kg body weight for 15 min) decreased mean pulmonary blood pressure from 41.2 +/- 6.7 mm Hg (mean +/- SD, before administration) to 36.1 +/- 6 mm Hg < or = 15 min (p < 0.05). The effect was reversed 10 min after discontinuation of PGI2 (40.9 +/- 6.3 mm Hg). Pulmonary vascular resistance index (339 +/- 138 dynes.s.cm-5.m2, before administration) was significantly (p < 0.05) reduced < or = 15 min (260 +/- 89 dynes.s.cm-5.m2) and increased again after discontinuation of PGI2 (341 +/- 142 dynes.s.cm-5.m2). The ratio of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) increased from 119 +/- 34 mm Hg (before administration) to 163 +/- 76 mm Hg (15 min after initiation of administration p < 0.05) and was reduced after PGI2 discontinuation (116 +/- 35 mm Hg). Heart rate, mean blood pressure, central venous pressure, and pulmonary arterial wedge pressure remained unchanged, whereas cardiac index was slightly reduced. We assume that PGI2 aerosolization is a beneficial technique, applied with a ventilator nebulization system. The beneficial effect might be caused by selective pulmonary vasodilatation in well-ventilated areas of the lung.

[Heart operations in patients older than 75. Results and postoperative rehabilitation]. / Herzoperationen bei Patienten älter als 75 Jahre: Ergebnisse und postoperative Rehabilitation.

A total of 164 patients with a mean age of 78.6 +/- 2.7 years and often critical preoperative conditions [New York Heart Association (NYHA) class III + IV, 78.7%] underwent cardiac operations [coronary artery bypass grafting (CABG) 97; valve replacement, 33; CABG + valve replacement, 18; replacement of ascending aorta and others, 18] with an in-hospital mortality of 8.5% (n = 14). Follow-up was completed for 147 patients (98%) after 16.5 +/- 10.8 months. Most patients were in a good clinical condition (NYHA I + II, 79.6%; late deaths, 8 patients, 5.4%) and more than 95% of patients lived at home or with relatives. Charges for hospital treatment dropped to one third after the hospitalization period for surgery in the first postoperative year compared to the year immediately preceding the cardiac operation.