Introduction: The potential benefits of Minimally invasive total hip arthroplasty (MIS THA) continues to be heavily debated. We hypothesized that the potential benefits of MIS THA may relate to factors such as patient selection, patient preconditioning, improvements in anesthesia technique, pain management, and not the incision size. This randomized, prospective study was designed to investigate the role of these confounding factors in general and aggressive rehabilitation in particular on the outcome of THA. Methods: 100 patients undergoing THA at our institution were randomized into one of four groups. Group A was patients who had standard THA (incision length> 10 cm) and received standard preoperative and postoperative care. Group B patients had THA using small incision (< 10 cm) and standard protocols. Group C patients had regular incision THA, but received aggressive rehabilitation and pain control regimen. Group D patients had THA through small incision and received aggressive regimen. Results: The demographic distribution amongst all the groups was similar. There was a significant improvement in function as measured by Harris Hip Score, LASA (validated rehabilitation score), SF-36, and lower extremity function test in all groups. The extent of functional improvement, home discharge, patient satisfaction, and analgesia requirement was better in patients who received aggressive preoperative and postoperative care regimen regardless of the size of their incision. There was no difference in estimated blood loss, mean operative time, transfusion needs, and complications between the groups. Discussion: This study highlights the importance of family education, patient conditioning, pre-emptive analgesia, and aggressive preoperative and postoperative rehabilitation in influencing the outcome of THA. The aforementioned factors, and perhaps not the surgical technique per se, may play a major role in imparting advantageous outcome to MIS THA that is reported by various investigators

Introduction: Minimally invasive total hip arthroplasty has evoked substantial controversy with regard to whether it provides superior outcomes compared with conventional total hip arthroplasty. The objective of this study was to compare the results of a minimal invasive direct anterior approach (MIDA) with those of a conventional lateral transgluteal approach (CLT). Methods: 120 patients (120 hips) admitted for unilateral total hip arthroplasty were randomized to undergo surgery via minimal invasive direct anterior or conventional lateral transgluteal approach. Patients with a body mass index of more than 35, previous hip surgery, preoperative neurological deficits and with an age of more than 80 years were excluded. Two surgeons performed all procedures. To estimate muscle damage serum creatinkinase was assessed. Blood loss was calculated according to Rosencher by comparing preoperative to postoperative hematocrit. Postoperative pain and the ability to perform the activities of daily living were recorded in a dairy via modified WOMAC first on a daily basis, then on each second day and finally once a week for a total of 12 weeks. WOMAC questionnaire and SF-36 were administered at 6 weeks and 3 months follow-up. Results: The groups were similar demographically. Patients in MIDA group had significantly less total blood loss (p = 0.006), postoperative blood levels of creatinine kinase were significantly lower (p = 0.001). Operative time was similar in both groups, we found no difference in component placement. Physical component summary of SF-36 at 12 weeks follow-up showed a significant benefit for the MIDA group. Averaged modified WOMAC scores and their pain and function subscores demonstrated a clear advantage on every recorded day during the first 12 weeks for MIDA. Median WOMAC sum score and respective pain as well as function subscores were better in the MIDA group at 6 and 12 weeks follow up. Conclusions: A minimally invasive direct anterior approach is superior to a conventional lateral transgluteal approach with regard to blood loss and muscle trauma, resulting in better health related quality of life in the first three months after operation

In recent years advances in operative techniques have allowed surgeons to perform total hip arthroplasty (THA) through incisions much smaller than those used previously. Potential advantages of these techniques include the reduction of blood loss and pain in the immediate postoperative period and preserving muscle function. Potential disadvantages might include increased wound infection rate due to skin ischemia, intraoperative neurovascular injuries, and component malposition. This in turn may lead to long term complications, such as instability, osteolysis, and loosening. The purpose of this study is to present our results with total hip arthroplasty performed through a minimal invasive technique which is a modification of the standard posterolateral approach. Methods: In this retrospective study 91 consecutive patients underwent primary total hip arthroplasties were reviewed. The surgeries were performed at our institution from January 2001 to December 2003. Surgical indications included primary osteoarthritis, subcapital fractures, malignancy, hip displasia, Otopelvis, rheumatoid arthritis and AVN. Exclusion criteria included revision hip arthroplasty, and cemented operations. A modification of the standard posterlateral approach was used. Standard hip arthroplasty instruments along with curved acetabular reamers and impactor were used. Incision extent was determined by the size of the acetabular component. A fully Hidroxyapetite coated stem, and porous coated acetabullar component were used. Immediate full weight bearing postoperative regimen was allowed in all cases. Results: In 17 patients (group A) the indication for surgery was a recent subcapital fracture. 74 patients (group B) had no trauma. The average age was 64.2 in group A and 65.1 in group B. No case of deep infection was documented in either group. 5 patients in group B had a single event of a posterior dislocation that was treated successfully with closed reduction. No dislocation occurred in group A. 35% (4) of group A and 41% (22) of group B did not require postoperative blood transfusions. 47% (6) and 36% (14) respectively needed transfusion of 3 blood units or more. Average hospitalization time was 6 days. None of the patients in both groups needed re-operation. Conclusions: Minimally invasive total hip arthroplasty is associated with a short hospitalization period and relatively low rate of blood transfusion. No major wound healing problems were documented in our series. It appears that the relatively high dislocation rate might be explained partly due to the common use of ceramic inserts. Further modification of the technique for proper acetabular component orientation is needed. However, more prospective with longer follow-up research must be conducted before definitive recommendations can be made

Minimally invasive total hip replacement surgery not only decreases the number of visual cues necessary for proper acetabular component position, the small incision makes it technically more difficult to use traditional mechanical alignment guides. Furthermore, traditional mechanical guides have been shown to be unable to accurately predict component position as determined by intraoperative computer measurements.[ 1,2 ] Computer assisted intraoperative navigation can enable minimally invasive surgery by giving the surgeon immediate intra-operative feedback of actual component position. We wished to compare the intraoperative computer determined measurement of acetabular inclination with the postoperative radiographic measurement of inclination in order to validate the results of the computer assisted measurements in the clinical setting. To determine whether computer assisted navigation of the acetabular component allows the surgeon to accurately place the prosthesis in minimally invasive hip replacement and to compare the results of intraoperative navigation with the postoperative radiograph. 42 consecutive patients underwent a minimally invasive posterior approach for total hip arthroplasty with the assistance of CT based intraoperative navigation with the BrainLAB VectorVision software. Preoperative surgical planning was performed after acquisition of a CT scan. All components were templated to be placed in 45 degrees of inclination and 25 degrees of anteversion. Intraoperatively, cementless acetabular components were aligned with the computer navigation at these values prior to implant impaction. Because of the press fit nature and limited soft tissue exposure, many components would shift during impaction. Final component position was then verified and values recorded by detecting points on the acetabular surface. If the prosthesis was felt to be in an acceptable position, no attempt was made to modify component position to the predetermined values in order to avoid potentially compromising component fixation. Postoperative supine AP pelvis radiography was then used to determine final inclination. Measurements were made by drawing a line perpendicular to the acetabular teardrop and parallel to the acetabular component and measured with a standard goniometer. These data were then placed in an SPSS database and analyzed by an independent statistician. Assessing acetabular component position in routine total hip arthroplasty has been shown to be unreliable even with experienced surgeons with mechanical alignment guides. [1,3] In minimally invasive total hip arthroplasty, routine visual cues are limited and mechanical instruments are difficult to place in the small operative wounds making an already difficult task even more difficult. CT based image guided surgery can has been shown to improve the acetabular component position intraoperatively 2. However, postoperative validation studies comparing the intraoperative computer assessment with the postoperative radiographic measurement are scarce. [ 2 ] In this consecutive series, which represents the author’s first experience with this technology, several conclusions can be made. First, the act of impacting a solid, porous coated, hemispherical cementless acetabular component in minimally invasive hip surgery often leads to a final component position different from the intended position. Second, computer generated determination of implant position is reliable but care must be taken to make sure the reference arrays do not lose fixation during the procedure or spurious results can occur. Third, routine AP pelvis radiographic measurements are not accurate enough to determine whether the computer determined values are accurate. In spite of these measurement inaccuracies, the computer determined results and the radiographic results were within 10 degress 95 % of the time which is far more accurate than results obtained with mechanical alignment tools 3. Finally, further validation studies need to be done with postoperative CT scanning to determine the accuracy of the intraoperative computerized measurements and determine the measurement errors inherent in the clinical setting. Given these limitations, computer assisted navigation improves the accuracy and reliability of acetabular component position over traditional mechanical instruments and can be utilized in minimally invasive hip surgery to assist in the appropriate placement of the acetabular prosthesis