Peripheral nerve injury is an uncommon but serious complication of hip surgery that can adversely affect the outcome. Several studies have described the use of electromyography and intra-operative sensory evoked potentials for early warning of nerve injury. We assessed the results of multimodal intra-operative monitoring during complex hip surgery. We retrospectively analysed data collected between 2001 and 2010 from 69 patients who underwent complex hip surgery by a single surgeon using multimodal intra-operative monitoring from a total pool of 7894 patients who underwent hip surgery during this period. In 24 (35%) procedures the surgeon was alerted to a possible lesion to the sciatic and/or femoral nerve. Alerts were observed most frequently during peri-acetabular osteotomy. The surgeon adapted his approach based on interpretation of the neurophysiological changes. From 69 monitored surgical procedures, there was only one true positive case of post-operative nerve injury. There were no false positives or false negatives, and the remaining 68 cases were all true negative. The sensitivity for predicting post-operative nerve injury was 100% and the specificity 100%. We conclude that it is possible and appropriate to use this method during complex hip surgery and it is effective for alerting the surgeon to the possibility of nerve injury.

Concerns recently arose regarding hip resurfacing arthroplasty (HRA), mainly referring to the metal-on-metal articulation that results in increased metal ion concentrations and that may be associated with weird soft tissue reactions. Although a number of short-term reports highlighted excellent and encouraging outcomes after HRA, mid- to long-term follow-up studies are sparse in the current literature. This study aimed to determine the five-year results of HRA using the Durom^® prosthesis in the first consecutive 50 cases. We prospectively assessed clinical and radiographic data for all patients undergoing HRA with this implant. Follow-ups were scheduled at six weeks, one year, two years and five years after surgery. All complications, revisions and failures were noted. Harris Hip Scores (HHS) and the range of motion (ROM) were determined preoperatively and at each follow-up. Oxford Hip Scores (OHS) and University of California at Los Angeles (UCLA) activity levels were determined at the last control. Comparisons were performed using paired t-tests after testing for normal distribution. The cohort comprised 13 women and 36 men (50 hips) with a mean age of 53.3 ± 10.7 years and a mean BMI of 25.9 ± 3.7 kg/m2. After a mean follow-up of 60.5 ± 2.3 months five hips had to be revised, corresponding to a resvision rate of 10%. There occurred two femoral neck fractures (after two and eleven months) and one aseptic loosening of the femoral component (after 68 months). One implant was exchanged to a conventional stem-type design due to persistent hip pain (after eight months), and one hip underwent a femoral offset correction due to a symptomatic impingement between the neck and the cup (after 29 months). There occurred no intra- or other postoperative complications. Clinically, ROM significantly improved after surgery. Hip flexion increased from 91.1 ± 15.8° to 98.9 ± 6.5° (p=0.0007), internal rotation from 5.5 ± 6.9° to 11.1 ± 8.1° (p=0.0005), external rotation from 19.2 ± 12.5° to 28.8 ± 9.1° (p=0.0001), and abduction from 27.3 ± 10.5° to 40.2 ± 11.0° (p< 0.0001). The HHS significantly increased from 55.9 ± 12.3 points to 96.5 ± 8.5 points. The OHS averaged 14.3 ± 3.0 points, and UCLA activity levels averaged 7.7 ± 1.7. The present results demonstrate that despite satisfactory clinical outcomes in terms of patient scores and ROM, the high revision rate of 10% after a mid-term follow-up is disappointing.

There is only a paucity of information on the outcome of resurfacing arthroplasty in patients suffering from hip osteoarthritis secondary to developmental dysplasia (DDH). When performing arthroplasty in dysplastic hips, the anatomic abnormalities offer reconstructive challenges, in particular in resurfacing. The present study was therefore conducted to address the following questions: Can hip resurfacing arthroplasty provide satisfactory clinical results in patients with DDH? Can the patients return to sports and recreational activities? Can the hip biomechanics be restored? And finally, can surface arthroplasty reestablish a normal, symmetric gait pattern? The study comprised 24 consecutive patients (32 hips) with a mean age of 44.2 years who underwent surface replacement due to hip osteoarthritis secondary to DDH. Surgery was performed by two senior surgeons using either the Durom implant or the Birmingham Hip Resurfacing prosthesis, dependent on the surgeon’s preference. At a mean follow-up of 43 months, all patients were evaluated cross-sectionally. We assessed clinical and radiographical data and investigated spatiotemporal gait parameters using an electronic mat. The Harris Hip Score improved from 54.7 +/−13.3 to 97.3 +/−5.2 (p< 0.001) and University of California at Los Angeles (UCLA) activity levels increased from 5.3 +/−2.0 to 8.6 +/−1.6 (p< 0.001), respectively. Hip flexion improved from 95.7° +/−16.5° to 106.7° +/−10.6° (p< 0.001). At a mean of 11.2 +/−4.8 weeks after surgery, all patients returned to sports activity. They participated in a mean of 6.0 +/−2.6 different disciplines, 2.8 +/−1.3 times and 4.1 +/−3.6 hours per week. The most common disciplines were cycling, swimming, exercise walking and downhill-skiing. Spatiotemporal parameters of gait demonstrated a symmetrical gait pattern without major differences to normative data. Both, the hip lever arm ratio and the femoral offset increased significantly (p< 0.001) from 0.48 +/−0.07 to 0.57 +/−0.08 and from 39.3 +/−8.2 mm to 45.6 +/−6.2 mm, respectively. Grade I heterotopic ossifications were seen in two hips, there were no Grade II or III ossifications. Two surface replacements failed, both failures could be attributed to surgical errors. The surface arthroplasty risk index was 3.2 +/−1.4 for the entire cohort and 4.5 for the revision cases. Femoral radiolucencies were detected in ten of the remaining 30 hips. The present study demonstrated that hip resurfacing achieved satisfactory clinical results in patients with hip osteoarthritis secondary to DDH. The failure rate of 6.3% did not reach our expectations, however, both failures could be attributed to surgical errors. Further follow-up is nevertheless of utmost importance to assess the significance of femoral stem radiolucencies in this young and active group of patients.

Introduction: Resurfacing arthroplasty is rapidly gaining popularity, the patients are in many cases very satisfied with the result. However some patients continue to complain about persistent groin pain, which is not clearly understood and attruibuted to different causes.

We identified femoro-acetabular impingement as a source of pain, which promptly disappeared after surgical off-set restoration.

Method: Since 2002 we implanted 390 hip resurfacing systems. At a one-year follow-up 16 patients complained about groin pain, especially when starting to walk.

In 6 patients the clinical examination and the rx could demonstrate femoro-acetabular impingement. In four cases this was due to anterior osteophytes of the femoral neck, in two cases it was due to retroversion of the femoral implant. These 6 patients were revised.

Results: During surgery femoro-acetabular impingement between these osteophytes on the femoral neck and the acetabular rim or the implant could be demonstrated. The head-neck off-set was restored with a high-speed burr. Interestingly rapid bleeding of the femoral neck was noted in all cases confirming the presence of vital bone. After surgery five of the six patients were painfree after 6–12 weeks. One patient did not experience a difference until now. There were no femoral neck fractures seen after this procedure.

Conclusion: Femoro-acetabular impingement seems to be a common source of persistent groin pain after hip resurfacing. Care has to be taken to restore the head-neck offset during implantation.

Aim: The aim of our retrospective study was to evaluate the precision of implantation of two different resurfacing systems and if incorrect positioning is a risk factor for implant failure.

Method:. We started with the Birmingham Hip Resurfacing system (MMT,UK) and later introduced the Durom resurfacing system (Zimmer). We analysed the follow-up rx of all patients operated in our clinic.

We measured the inclination of the cup, the CCD-angle of the head component, the alignement in respect to the neck axis, if the component had an eccentric position or if superior or inferior notching had occured. We compared the rate of failure of the two systems.

Patients: In 90 patients a Mc Minn hip resurfacing system was implanted. The mean age in this group was 52 years (range 29 – 68 years). There were 64 male and 26 female patients.

In 75 patients we implanted a Durom resurfacing system. The mean age in this group was 53 years (range 20 – 72 years). There were 55 male and 20 female patients.

Results: In both groups the mean CCD angle was higher than before surgery, indicating that the head component was usually implanted in a slight valgus position. In 20 % of the cases component alignement was not ideal in both systems. There were four revisions of patients with the Durom system and three revision of patients with the McMinn system. The main reason for failure was weakening of the superior neck portion.

Conclusion: As we were in the learning curve in hip resurfacing in a high number of cases positioning of the implant was not as it should be. This remained in most cases without clinical consequences but weakening of the superior neck portion seems to be the main reason leading to failure.

Introduction: The standard implant for patients with rheumatoid arthritis is a cemented system. Early aseptic loosening is a major concern in patients with bad bone quality, usually seen in inflammatory arthritis

Aim of the study: The aim of this retrospective study is to find out, whether the cementless CLS-stem is an appropriate implant for patients with rheumatoid or juvenile arthritis.

Material and methods: Between 1984 and 2002 63 patients with rheumatoid or juvenile arthritis were treated with a cementless Stem (CLS) in our clinic. The mean age was 53 years (range from 25 to 71 years). We evaluated the x-rays (aseptic loosening and other complications) as well as the clinical outcome (Harris Hip Score). Patients with a minimum follow-up of 24 months (mean fu 5 years) were included in the study.

Results: There was no stem revision due to aseptic loosening. No patient had radiological signs of aseptic loosening. 8 patients suffered a fracture of the greater trochanter or the proximal femur during surgery. Two patients had to be revised for trochanteric problems.

Conclusion: The cementless CLS stem is an appropriate implant for patients with rheumatoid or juvenile arthritis. Careful implantation is necessary to avoid trochanteric or femoral fractures.

Aims: The aim of the study was a ten-year survivorship analysis of the cemented Weber stem. This cemented, collared stem is successfully implanted since 1968, but exact data were lacking until now. Methods: Between 1984 and 1990 1374 Weber stems have been implanted at our institution in 687 male and 687 female patients with an average age of 62 (63 resp.) years. After surgery and at regular intervals thereafter the patients are clinically and radiographically controlled. Those patients with incomplete data were contacted by telephone or by letter. Results: The Weber stem was combined in 623 cases with an Endler cup, which is an uncemented threaded polyethylen cup and in 612 cases with a Zwey-müller cup, a threaded titanium shell with a polyethylen inlay. In the other cases different cups in small numbers were used. The rate of intraoperative complications was 5% and the rate of postoperative complications was 6%.

310 patients (23%) had to be revised after an average duration of eight years. In 233 cases only the cup was revised, in 35 cases both components were revised and in 14 cases only the stem was revised.

In 222 of the 233 cup revisions (95%) the Endler cup had failed. In the 35 cases with revision of both components the Endler cup had failed in 28 cases. In the 14 stem revisions only in two cases an Endler cup was involved. The Endler cup resulted in a significant increase of stem revisions. The ten-year survivorship of all hips was only 82% due to the high failure rate of the Endler cup. If only the stem was analysed the ten-year survivorship increased to 96%. Conclusion: This high survival rate confirms the clinical impression of the excellent performance of the Weber stem.

We carried out the Bernese periacetabular osteotomy for the treatment of 13 dysplastic hips in 11 skeletally mature patients with an underlying neurological diagnosis. Seven hips had flaccid paralysis and six were spastic. The mean age at the time of surgery was 23 years and the mean length of follow-up was 6.4 years. Preoperatively, 11 hips had pain and two had progressive subluxation.

Before operation the mean Tönnis angle was 33°, the mean centre-edge angle was −10°, and the mean extrusion index was 53%. Postoperatively, they were 8°, 25° and 15%, respectively. Pain was eliminated in 7 patients and reduced in four in those who had preoperative pain. One patient developed pain secondary to anterior impingement from excessive retroversion of the acetabulum. Four required a varus proximal femoral osteotomy at the time of the pelvic procedure and one a late varus proximal femoral osteotomy for progressive subluxation.

Before operation no patient had arthritis. At the most recent follow-up one had early arthritis of the hip (Tönnis grade I) and one had advanced arthritis (Tönnis grade III).

Our results suggest that the Bernese periacetabular osteotomy can be used successfully to treat neurogenic acetabular dysplasia in skeletally mature patients.

We report seven cases in which open or closed reduction of a shoulder dislocation associated with a fracture of the humeral neck led to displacement of the neck fracture. Avascular necrosis of the humeral head developed in all six patients with anatomical neck fractures. All five anterior dislocations also had a fracture of the greater tuberosity and both posterior dislocations had a fracture of the lesser tuberosity. The neck fracture had not initially been recognised in three of the seven cases. In five cases attempted shoulder reduction led to complete displacement of the head segment, which was treated by open reduction and minimal internal fixation. In the other two cases, shoulder reduction caused only mild to moderate displacement which was accepted and the fracture was treated conservatively. We conclude that biplane radiography is essential before reduction of a shoulder dislocation. Neck fractures must always be ruled out, especially where there are tuberosity fractures. In our series, careful closed reduction under general anaesthesia with optimal relaxation and fluoroscopic control did not prevent iatrogenic displacement. Prophylactic stabilisation of the neck fracture should be considered before reduction of such a fracture-dislocation. It may be, however, that the prevention of displacement by prophylactic stabilisation does not always prevent late avascular necrosis; we observed this in one case.