HIP International

We report the clinical and radiological outcome of 99 Zweymuller metal on metal total hip arthroplasties in 84 patients followed up prospectively for a mean period of 9.5 (range, 6–15) years. There were 29 (34.5%) male and 55 (65.5%) female patients with a mean age of 62.85 years (range, 50–70 years) at the time of surgery. All patients had osteoarthritis. One acetabular component and one stem were revised due to aseptic loosening. One femoral stem was revised due to a periprosthetic fracture. HHS score improved from a preoperative mean of 62.56 points (SD 8.87) to a final postoperative follow-up mean of 93.48 (SD 7.7). Cumulative success rate for both implants at 13 years, with aseptic loosening as the end point, was 97.05%, while for both implants at 13 years, with revision for any reason as the end point, it was 91.17%. Satisfactory results were observed with the use of this prosthesis.

The short-term results of middle-aged patients with severe developmental dysplasia of the hip treated with subtrochanteric femoral shortening and cementless large diameter metal-on-metal total hip arthroplasty were retrospectively evaluated. Clinical and radiological results of 15 hips of 13 patients with Crowe IV developmental dysplasia of the hip were enrolled in this study. The average follow-up period was 49 months (36–62 months). The average age of patients at the time of surgery was 45.5 years (range, 36–65 years). Radiographs were evaluated for component position, subsidence, loosening, and osteolysis. Intraoperatively, two patients had a small proximal femoral shaft split that was held with a cable wire. The average preoperative Harris hip score was 58; at 3 years, 82. Trendelenburg sign was negative in 11 hips at the last assessment. Loosening, subsidence, infection, dislocation, hypersensitivity and neurovascular complications were not observed. One hip had to be revised 1 year after surgery because of nonunion at the osteotomy site. Our study shows that large diameter metal-on-metal total hip arthroplasty, incorporating subtrochanteric femoral shortening, decreases dislocation rate and provides excellent results for the completely dislocated hip.

The aim of the paper was to present the results achieved with triple pelvic osteotomy in the treatment of residual hip dysplasia, with special interest in identifying recurrences and complications and how to avoid them. 60 patients (76 hips) with developmental dysplasia of the hip (DDH), treated by the triple pelvic osteotomy according to Tönnis and modified by Vladimirov, were included in the study. Hips were evaluated radiologically with the center-edge (CE) angle, break of the Shenton-Menard arch and index of acetabular depth by Heyman-Herndon, and functionally using the Harris Hip Score (HHS). The postoperative results showed an average increase of the CE angle by a mean of 23.5±9.28 degrees, with a highly significant difference between the preoperative and final postoperative findings (t-test, t=-20.85, p<0.01). The mean HHS significantly improved (p<0.01). Total complication rate was 13, 1%, divided in: 1,3% (one case) of triple nonunion of iliac, pubic and ischial bones, 7,9% (six cases) of double nonunion of pubic and ischial bones, 2,6% (two cases) of peroneal palsy and 1,3% (one case) of infection. In this study the triple pelvic osteotomy showed to be reliable for acetabular dysplasia in adolescent and young adult, alone or in association with proximal femoral osteotomy and/or great trochanter distal advancement.

CT when compared to plain radiograph is known to be a more valid measure of acetabular component orientation. The validity of plain radiographs may be further compromised by large diameter metal femoral heads because of obscuration of the acetabular rim. We quantified this effect by measuring acetabular cup angles (inclination and version) of 49 metal on metal (MOM) hip resurfacings using plain radiographs and 3D CT based measurement. Bland-Altman plots revealed poor agreement between plain radiographic and CT based measurement with 2 standard deviation limits of agreements of: +7 to –15 degrees for cup inclination angle; and +16 to –31 degrees for cup version angle. The large differences between plain radiographic and CT measurement of cup positions are probably due to the large diameter metal femoral head that can obscure the cup margin. We have used a metal artefact reduction CT protocol with a 3D imaging software package to overcome this problem and measure cup position relative to the Anterior Pelvic Plane.

Seventy-seven patients implanted with unilateral resurfacing prosthesis were recruited from four centres. Serial whole blood samples were collected and ion levels were analysed. In most cases, the ion levels stabilized by 3 months. The 24 month median ion levels were 1.49ug/l for chromium and cobalt. In approximately 50% of patients the increase in chromium and cobalt level was less than 1ug/l. There were 6 patients with abnormally high metal ion levels. Of these 4 were significant outliers, had high ion levels that became apparent between 12 and 24 months after implantation, and had a high cup abduction angle. Not all patients with high cup abduction angles demonstrated high levels. There were differences in ion levels between the four centres that correlated with variation in acetabular component placement. Variability in ion levels was seen with the same prosthesis, underscoring the importance of surgical technique, longitudinal analysis, and multi-centre trials.

Hip resurfacing arthroplasty has conventionally been undertaken through the posterior approach. There has been evidence in the recently published literature to suggest that the posterior approach may compromise the blood supply to the femoral head, by disruption of the posterolateral hip capsule. Ganz et al have proposed the trochanteric ‘flip’ osteotomy through a lateral approach, to permit surgical dislocation of the hip without damaging the blood supply. The disadvantages, however, are that early full weight bearing is not permitted and there is an incidence of trochanteric delayed or non-union, which may require further treatment.

We describe a technique of hip resurfacing through a modified anterolateral approach preserving the posterolateral capsular blood supply. We describe our experience using this approach, and compare the results with our previously used Ganz trochanteric osteotomy. At a mean follow-up of two years, the outcome scores were not significantly different, and both groups had similar abductor strength. There were two cases of delayed union in the Ganz group, one of which required revision; there were no complications in the modified anterolateral group.

We examined the hypothesis that the circumferential osseous apposition around HA-coated implants forms a protective barrier against articular wear debris. Sixty-five hydroxyapatite-coated total hip arthroplasties in 57 patients (age <50years) with polyethylene-metal articulation were evaluated regarding PE-wear, osteolysis, and clinical outcome at a minimum of 10 years follow-up.

There was no correlation between PE-wear and osteolysis of the femoral zones or cup zones I and III. A strong Pearson correlation was found between polyethylene wear and osteolysis around cup zone II, where the cup only consisted of polyethylene (p<0,01). The aseptic failure rate was 1.5% for the femoral component and 4.5% for the cup after 10 years of follow–up. The average Harris Hip Score was 90 and the average Engh score for fixation was 23 after 10 years. Around HA-coated parts of the prosthesis bone formation remained stable, regardless of the degree of polyethylene wear. The average linear polyethylene wear was 0,16 mm/year.

The circumferential osseous apposition of the HA-coated implants possibly formed a protective barrier against articular wear debris. The use of cups with a backside gap resulted in PE-wear associated osteolysis in cup zone II and may be considered to be best avoided.

We studied a consecutive series of 81 cementless total hip arthroplasties in 80 patients using the second generation ESKA cementless spongy metal hip replacement. The study end-point was implant revision and both function as well as satisfaction with treatment outcome were assessed.

Mean age at the time of surgery was 50.9 years [range 23–73]. No patient was lost to follow-up and 75 patients (76 hips) could be included in the final analysis at a mean follow-up of 7.9 years [range 7.0–10.0]. Survival rate without loosening as the end-point was 100% for the femoral component and 99% for the acetabular component (one cup revision). Two cups and one stem had to be revised for recurrent dislocation, resulting in a total implant survival at follow-up of 99% for the femoral component and 96% for the acetabular component. Very good functional results were obtained with a mean Merle d' Aubigné score of 15.5 ± 2.9 at 7.9 years after surgery. Satisfaction with treatment outcome was reported in 88%. 95% of patients would recommend the performed procedure to a friend. Perioperative complications without revision occurred in eleven patients (14%).

We report excellent survival rates of the cementless spongy metal hip arthroplasty at a mean follow-up of eight years, particularly considering the young age of many of the patients.

Rehabilitation and patient satisfaction following a modified anterolateral approach for implantation of a total hip replacement (THR) were reviewed following 72 consecutive cases.

The Harris Hip and merle d'Aubigné Scores were recorded at 6 and 12 weeks postoperatively. The patient's satisfaction with regard to the surgical result and the need for analgesia for mobilization were recorded. Rehabilitation was assessed by postoperative crutch use.

Significant improvements of the Harris Hip and merle d'Aubigné scores were demonstrated. All patients thought their surgical outcome was good or better. 2 patients needed pain medicine on an irregular basis and 4 patients used crutches at 12 weeks.

This study demonstrates patient satisfaction and satisfactory rehabilitation following a modified anterolateral approach for minimally-invasive implantation of THR.

Lateral sided hip pain frequently presents to the orthopaedic clinic. The most common cause of this pain is trochanteric bursitis. This usually improves with conservative treatment. In a few cases it doesn't settle and warrants further investigation and treatment. We present a series of 28 patients who underwent MRI scanning for such pain, 16 were found to have a tear of their abductors. All 16 underwent surgical repair using multiple soft tissue anchors inserted into the greater trochanter of the hip to reattach the abductors.

There were 15 females and 1 male. All patients completed a self-administered questionnaire pre-operatively and 1 year post-operatively. Data collected included: A visual analogue score for hip pain, Charnley modification of the Merle D'Aubigne and Postel hip score, Oxford hip score, Kuhfuss score of Trendelenburg and SF36 scores.

Of the 16 patients who underwent surgery 5 had a failure of surgical treatment. There were 4 re ruptures, 3 of which were revised and 1 deep infection which required debridement. In the remaining 11 patients there were statistically significant improvements in hip symptoms. The mean change in visual analogue score was 5 out of 10 (p=0.0024) The mean change of oxford hip score was 20.5 (p=0.00085). The mean improvement in SF-36 PCS was 8.5 (P=0.0020) and MCS 13.7 (P=0.134). 6 patients who had a Trendelenburg gait pre-surgery had normal gait 1 year following surgery.

We conclude that hip abductor mechanism tear is a frequent cause of recalcitrant trochanteric pain that should be further investigated with MRI scanning. Surgical repair is a successful operation for reduction of pain and improvement of function. However there is a relatively high failure rate.

Restoring femoral offset (FO) is an important factor for the success of total hip arthroplasty (THA). However, earlier methods of measuring FO do not take in consideration the positioning of the acetabular component. In this study we introduce and evaluate a new radiological method of measuring FO as the horizontal distance between the femoral axis and the midline of the pelvis, at the height of the lateral tip of the greater trochanter.

Ten patients operated with THA underwent a plain radiographic examination of the pelvis (AP view) and a CT scanogram for the pelvis and lower limbs (scout view). The radiological FO measurement using the new method was initially compared to FO measurement on CT scanogram and subsequently to the traditional radiological method of measuring FO. We tested the interobserver reliability and the intraobserver reproducibility of the new method.

We found an excellent agreement between the new radiological method and the CT measurement and between the new radiological method and the traditional radiological method. We also found an excellent interobserver reliability and an intraobserver reproducibility of the new method. We believe the new method is easier than and as reliable as previously described methods.

To assess the effectiveness of indirect Magnetic Resonance arthrography (i-MRa) in the detection of chondral and labral lesions related to femoro-acetabular impingement (FAI) a series of 21 hip joints in 17 patients with a clinical diagnosis of FAI were examined either with standard MR imaging, i-MRa and direct-MR arthrography (d-MRa). Sensitivity and accuracy of i-MRa in detecting chondral, labral and tardive lesions were calculated and compared with standard MR. The agreement in detecting endoarticular damage between i-MRa and d-MRa and the interobserver agreement was assessed by K statistic (p<0.05). Finally the presence of trocanteric bursitis was evaluated. I-MRa showed higher values of both sensivity and accuracy than standard MR in detecting chondral damage, with an increase to 92% for the first item and 95% for the second. The same was noticed in labrum evaluation with an increase to 88% and 90% respectively. The level of agreement between i-MRa and d-MRa in detection of chondral lesions was excellent, substantial for the labral damage and absolute for early osteoarthritic changes. An excellent interobserver agreement resulted in detection of both chondral and labral damages with i-MRa. In 6 hips (28,5%) we also found the presence of peri-trochanteric soft tissue inflammation that indicated the possibility of extrarticular involvement in FAI. Indirect-MRa can be considered a valid method of assessing endoarticular damage related to FAI, in comparison to d-MRa. It should be performed instead of standard MR if d-MRa is not available.

We present a patient in whom an uncemented porous-coated acetabular cup underwent early catastrophic failure due to debonding and was successfully managed with a revision total hip arthroplasty. Early bead shedding of an acetabular cup leading to a sudden component failure requiring revision surgery is a rare event.

Arthroscopy is used increasingly in the diagnosis and treatment of hip disorders of both natural and prosthetic hip joints. Complications tend to be transient and self-resolving. This is the first report of a hip arthroscopy destabilizing a prosthetic hip resulting in dislocation of the joint.

We report a case of late small intestine perforation by an acetabular cup fixation screw after total hip arthroplasty (THA). A 79-year-old-woman underwent THA for hip osteoarthritis 13 years previously at another hospital. Although the acetabular cup fixation screw protruded into the pelvis, she had no symptoms. She later presented with peritonitis and was admitted to the hospital and prescribed antibiotic therapy. Computed tomography showed that the screw was adjacent to the intestine and was the likely cause of her peritonitis. After the peritonitis healed, she was referred to our hospital for surgical treatment of the screw. During laparotomy, we performed a resection of the intra-pelvic portion of the screw. The screw perforated the small intestine, so a small intestinal resection was also performed. The patient had an uneventful recovery.

Osteoporotic hip fractures are common in our setting. Poor bone quality favors complications of the osteosynthesis procedures used to treat these patients. Lag-screw cut-out through the femoral head is not uncommon (2%), but pull-out of side plate screws is very unusual. We present the case of a patient with a stable osteoporotic fracture treated by osteosynthesis using a four-hole plate, who presented with a pull-out following a low-energy fall.