European multidisciplinary consensus statement on the use and monitoring of metal-on-metal bearings for total hip replacement and hip resurfacing.

INTRODUCTION: There is an ongoing debate about the optimal use of metal-on-metal (MoM) bearings in total hip replacement, since there are uncertainties about local and systemic adverse effects due to wear and corrosion of these bearings. Despite various national recommendations, efforts to achieve international harmonization of specific evidence-based recommendations for best practice are still lacking. HYPOTHESIS: An international consensus study group should be able to develop recommendations on the use and monitoring of MoM bearings, preferably at the European level, through a multidisciplinary approach, by integrating the perspectives of various stakeholders. MATERIALS AND METHODS: Twenty-one experts representing three stakeholder groups and eight countries participated in this European consensus study, which consisted of a consensus meeting, subsequent structured discussion, and consensus voting. RESULTS: The current statement defines first of all benefits, local and systemic risks, as well as uncertain issues related to MoM bearings. Safety assessment after implantation of MoM comprises all patients. A closer follow-up is recommended for large head MoM (≥36mm) and resurfacing. In these implants basic follow-up should consist of x-rays and metal ion measurement of cobalt in whole blood, performed with GF-AAS or ICP-MS. Clinical and/or radiographic abnormality as well as elevated ion levels needs additional imaging (ultrasound, CT-scan and/or MARS-MRI). Cobalt values less than 2 µg/L are probably devoid of clinical concern, the threshold value for clinical concern is expected to be within the range of 2-7 µg/L. DISCUSSION: This is the first multinational, interdisciplinary, and multiprofessional approach for developing a recommendation for the use and monitoring of MoM bearings in total hip replacement. The current recommendations are in partial agreement with previous statements regarding the extent of follow-up and imaging techniques. They however differ from previous communications regarding measurement of metal ions and especially the investigated medium, technique, and eventual threshold levels. LEVEL OF EVIDENCE: Level V, expert opinion/agreement conference.

Minimally invasive compared with traditional transgluteal approach for total hip arthroplasty: a comparative gait analysis.

BACKGROUND: Minimally invasive total hip arthroplasty is purported to allow an improved and faster rehabilitation in the immediate postoperative period because of reduced soft-tissue damage compared with total hip arthroplasty performed with use of a standard approach. In the present study, a minimally invasive approach was compared with a traditional standard approach in terms of the effect on gait kinematics as demonstrated with gait analysis and electromyography. METHODS: Twenty randomized patients who underwent a primary total hip replacement with use of a minimally invasive modified Watson-Jones approach (minimally invasive group) were compared with a group of twenty patients who underwent a total hip arthroplasty with use of a standard transgluteal Hardinge approach (standard group). All patients received the same cementless implant, inserted with use of standard instruments, and all operations were performed by a single, experienced surgeon. The patients were evaluated with use of three-dimensional gait analysis and dynamic electromyograms at three time points: preoperatively, ten days postoperatively, and twelve weeks postoperatively. Temporospatial and joint-kinematic parameters were evaluated. RESULTS: There were no significant differences between the two groups with regard to the temporospatial variables of velocity, cadence, step length, and stride length at any tested time point. With regard to the range of motion of the operatively treated hip, the minimally invasive group had a smaller decrease at the ten-day time point in comparison with the standard group. However, this finding was not significant. The reduction in the range of motion was mainly caused by reduced hip extension. A compensatory increase in the pelvic tilt was observed in both groups. One patient in the standard group showed a positive Trendelenburg gait ten days postoperatively; it had disappeared completely at the twelve-week time point. CONCLUSIONS: With regard to gait kinematics in the early postoperative period (three months), the present study showed no significant benefit for patients who underwent a total hip arthroplasty through a minimally invasive Watson-Jones approach in comparison with those who were managed with a standard transgluteal approach.

Retrieval analyses of highly cross-linked polyethylene acetabular liners four and five years after implantation.

Two Durasul highly crosslinked polyethylene liners were exchanged during revision surgery four and five years after implantation, respectively. The retrieved liners were evaluated macroscopically and surface analysis was performed using optical and electron microscopy. A sample of each liner was used to determine the oxidation of the material by Fourier transform infrared spectroscopy. Samples of the capsule were examined histologically. The annual wear rate was found to be 0.010 and 0.015 mm/year, respectively. Surface analysis showed very little loss of material caused by wear. Histological evaluation revealed a continuous neosynovial lining with single multinucleated foreign-body giant cells. Our findings showed no unexpected patterns of wear on the articulating surfaces up to five years after implantation and no obvious failure of material.

Strategies for the prevention and management of osteoarthritis of the hip and knee.

Osteoarthritis (OA) is one of the most common forms of musculoskeletal disorders and incurs significant economic, social and psychological costs. OA increases in prevalence and also progresses with aging. Clinically OA is characterised by joint pain, crepitus, stiffness after immobility and limitation of movement. Many cases are 'idiopathic' (disease or condition of unknown course or which arises spontaneously), but OA can also be the end result of several other conditions or due to the combination of several other factors. There are various lifestyle factors that increase the risk of developing OA. Preventable or modifiable risk factors include obesity, occupational factors, sports participation, muscle weakness, nutritional factors and hormonal influence. Pharmacological therapies reduce pain and may reduce joint damage. Surgical interventions correct altered biomechanics to prevent OA. For severely damaged joints, partial or total replacement of the joint is possible for all of the large joints that are commonly affected by OA. OA is commonly associated with a limited function that can be improved with a wide variety of rehabilitative interventions: joint specific exercises, physical fitness, physical modalities. Education and self-management are very important to prevent overuse and to use the joints in the most adequate way.

Cementless total hip arthroplasty using a threaded cup and a rectangular tapered stem. Follow-up for ten to 17 years.

We carried out a clinical and radiological review of 103 cementless primary hip arthroplasties with a tapered rectangular grit-blasted titanium press-fit femoral component and a threaded conical titanium acetabular component at a mean follow-up of 14.4 years (10.2 to 17.1). The mean Harris hip score at the last follow-up was 89.2 (32 to 100). No early loosening and no fracture of the implant were found. One patient needed revision surgery because of a late deep infection. In 11 hips (10.7%), the reason for revision was progressive wear of the polyethylene liner. Exchange of the acetabular component because of aseptic loosening without detectable liner wear was carried out in three hips (2.9%). After 15 years the survivorship with aseptic loosening as the definition for failure was 95.6% for the acetabular component and 100% for the femoral component.

Tribological considerations for a new hip system.

PURPOSE OF THE STUDY: This paper was initiated to evaluate a new total hip system based on cementless fixation and focusing options for different articulations within a single hip system. MATERIAL AND METHODS: 100 patients provided with the cementless Variall hip system were evaluated clinically and radiographically. The 59 female and 41 male patients were followed for a minimum of 3 years postoperative. They were clinically evaluated using the Harris Hip Score. Radiographic analysis was based on plain x-rays at the latest follow-up evaluation. RESULTS: The evaluated patients achieved an excellent clinical result with an average Harris Hip Score of 94,3 points after an average follow-up of 42 months. The radiographic evaluation of the threaded cup did not exhibit any migration of the implant nor could we find radiolucencies. All tapered stems were radiographically stable. Due to the modified proximal design and the macrostructure an improved stem bone interface was found during the follow-up period. DISCUSSION The new cementless cup with its cylindrical threads and the spherical floor achieves an anatomic fit within the acetabulum and provides excellent primary stability. The design of the gamma inlay offers the fixation of ceramic and metal articulations without polyethylene interface. Additionally, options for conventional and cross-linked polyethylenes are available. These facts make the cup a cost-effective device. The design of the new uncemented stem guarantees a high degree of primary stability and excellent rotational stability due its rectangular cross section. This pressfit is further enhanced by the proximal macrostructure of the implant, again ensuring an excellent bond between prosthesis and bone. CONCLUSION: Thanks to the versatility of all the components this comprehensive new total hip prosthesis offers many options for a long-term successful implant. Additionally, it is a cost-effective solution - an important fact of nowadays strained financial situation in public health care.

Blood analysis for trace metals in metal-on-metal, ceramic-on-ceramic and metal-on-cross-linked PE bearings in total hip arthroplasty.

We obtained postoperative blood concentrations of Co, Cr, Mo, Ti, Al and Nb in 75 patients undergoing primary THA at our institution between January 1998 and December 2000. All patients were treated with the same prosthetic device (Alloclassic VARIALLTM, Zimmer, Winterthur, Switzerland) using three types of articulations: metal-on-metal (METASULTM ), ceramic-on-ceramic (CERASULTM) and metal-on-cross linked polyethylene (DURASULTM). 25 patients out of each articulation-group were evaluated by blood analysis 24-38 months after surgery. The patients were submitted to strict criteria of inclusion. Comparing the three articulation-groups there were no significant differences in the categories age, follow-up time and preoperative blood level of creatinine. The Al-, Ti- and Nb-blood levels were all below their detection limit. Regarding the median blood concentrations of Mo, we found no statistically significant differences comparing the three articulations (p>0.05). The median Co blood concentration in the ceramic group was 0.19 ng/mL, 0.69 ng/mL in the metal group and 0.19 ng/mL in the cross-linked PE group. The difference between the metal and ceramic group and between the metal and polyethylene group is statistically significant (p=0.001 in both comparisons). The median blood concentration of Cr was 0.19 ng/mL in the ceramic and in the cross-linked PE group, and 0.47 ng/mL in the metal group, the difference being statistically significant (p=0.003 and p=0.0002). Although the blood concentrations of Co and Cr were significantly higher in patients with a metal-on-metal articulation they were far from reaching toxic levels. (Hip International 2005; 15: 136-42).

Chevron osteotomy in hallux valgus. Ten-year results of 112 cases.

The Chevron osteotomy was described in 1976. There have, however, been only short- to mid-term follow-up reviews, often with small numbers of patients. We looked at 112 feet (73 patients) with a minimum follow-up of ten years following Chevron osteotomy with a distal soft-tissue procedure. Clinical evaluation was calculated using the hallux score of the American Orthopedic Foot and Ankle Society (AOFAS). For 47 feet (30 patients), the results were compared with those from an interim follow-up of 5.6 years. The AOFAS-score improved from a pre-operative mean of 46.5 points to a mean of 88.8 points after a mean of 12.7 years. The first metatarsophalangeal (MTP) angle showed a mean pre-operative value of 27.6 degrees and was improved to 14.0 degrees. The first intermetatarsal (IM) angle improved from a pre-operative mean value of 13.8 degrees to 8.7 degrees. The mean pre-operative grade of sesamoid subluxation was 1.7 on a scale from 0 to 3 and improved to 1.2. Measured on a scale from 0 to 3, arthritis of the first MTP joint progressed from a mean of 0.8 to 1.7. Comparing the results in patients younger and older than 50 years, the Chevron osteotomy performed equally in both age groups. Analysing the subgroup of 47 feet with a post-operative follow-up of both 5.6 and 12.7 years, the AOFAS pain and the overall score showed a further improvement between both follow-up evaluations. The MTP angle, first IM angle and sesamoid position remained unchanged. The progression of arthritis of the first MTP joint between 5.6 and 12.7 years post-operatively was statistically significant. Only one patient required a revision procedure due to painful recurrence of the deformity. Excellent clinical results following Chevron osteotomy not only proved to be consistent, but showed further improvement over a longer follow-up period. The mean radiographic angles were constant without recurrence of the deformity. So far, the statistically significant progression of first MTP joint arthritis has not affected the clinical result, but this needs further observation.

Experimental investigation of threaded cup performance during insertion in total hip replacement.

Cementless threaded cups are often used in Europe on the acetabular side of a total hip arthroplasty (THA), with some products achieving excellent clinical results. Titanium and titanium alloys are nowadays accepted as the materials of choice for these implants. In contrast, however, there is no consensus about the ideal thread design. This in vitro and human cadaver study aimed to compare the insertion torques of commercially available threaded cups during insertion. The aims were (1) to see whether the clinical experience of surgeons using these cups specifically related to insertion torque could be reproduced in the experiment and (2) to assess whether or not the cup size and thread design has a statistically significant influence on the insertion torque. Using a biaxial testing machine the cups were screwed into pre-machined polyurethane blocks and the insertion torque was recorded by an appropriate sensor. Clear differences were seen between the four different designs. A variance analysis using statistical software showed that both the cup size (p=0.003) and the thread design (p=0.0009) significantly affect the insertion torque. The human cadaver study allowing a right-left comparison of two different cups within the same specimen confirmed the insertion torque data of the experimental study. In addition, the trends observed during the course of the insertion agreed with the clinical experience of the orthopaedic surgeons consulted as part of this study. (Hip International 2004; 14: 11-7).

[Quality of life five years after total or partial knee arthroplasty]. / Lebensqualität von Patienten fünf Jahre nach Knie-Arthroplastik.

AIM: Multiple aspects of health-related quality of life were assessed in elderly patients after total or partial knee arthroplasty. METHOD: 187 subjects who had undergone knee arthroplasty 5 years ago were asked to fill out 3 questionnaires, the Nottingham Health Profile, the SF-36 Health Survey and the Funktionsfragebogen Hannover. Results were compared to standard data. The impact of gender and age was analyzed, and 3 different types of prostheses were compared. RESULTS: Response rate was 74 % (n = 138). Regarding the main symptoms pain and subjective function, as well as almost all other aspects, quality of life proved to be significantly reduced compared to the age-matched general population. Correlations between age and quality of life scales were low. Different types of implants led to similar results in all scales but one. CONCLUSION: 5 years after knee arthroplasty the quality of life is markedly reduced compared to the general population. The impact of age, gender, and type of implant is low. In our sample, the SF-36 showed methodological advantages compared to the NHP for the measurement of subjective pain and function.

Intertrochanteric osteotomy for avascular necrosis of the head of the femur. Survival probability of two different methods.

We have compared different types of intertrochanteric osteotomy for avascular necrosis of the hip and evaluated their performance in the light of improving outcome after total hip arthroplasty (THA). During a period of 14 years we performed 63 flexion osteotomies (partly combined with varus or valgus displacement), 29 rotational osteotomies, 13 varus osteotomies, eight medialising osteotomies and two extension osteotomies. The mean period of follow-up for all 115 operations was 7.3 years (maximum 24.6). At follow-up, 27 of 29 patients with a rotational osteotomy had already undergone a THA, compared with 36 of 63 after flexion osteotomy. A high incidence of complications (55.2%) was seen early after rotational osteotomy, compared with 17.5% after flexion osteotomy. For all osteotomies there was a high correlation between the size of the necrotic area and the incidence of failure, which also correlated with the preoperative Ficat and Steinberg stages. Using Kaplan-Meier survivorship analysis, Sugioka's rotational osteotomy showed a survival probability after five years of 0.26 (95% confidence interval 0.49 to 0.14), and after ten years of 0.15 (CI 0.36 to 0.06). The survival probability for flexion osteotomy was 0.70 (CI 0.83 to 0.59) after five years and 0.50 (CI 0.65 to 0.38) after ten years. The subgroup of flexion osteotomy with a necrotic sector of less than 180 degrees achieved the best survival probability of 0.90 (CI 1.00 to 0.80) after five years and 0.61 (CI 0.84 to 0.45) after ten years. The indications for intertrochanteric osteotomy for avascular necrosis of the hip have to be addressed critically. Even flexion osteotomy in cases with small areas of necrosis provides only temporary benefit. Rotational osteotomy was associated with a high incidence of complications.

Core decompression in early stages of femoral head osteonecrosis--an MRI-controlled study.

We treated 45 hips with idiopathic necrosis of the femoral head stages I-III with core decompression. Average age of patients was 41 (27-68) years and average follow-up 68.9 (31-120) months. In 30 hip joints in stage I, 29 showed no radiographic progression and a complete remission of the changes consistent with necrosis on MRI at the last follow-up. In 27 patients the clinical result based on the Harris Hip Score (HHS) assessment--was excellent (average HHS 91.9 points). Of nine hips in stage II, four had received a total hip arthroplasty, one had deteriorated to stage IV, and four were still classified as stage II (average HHS 95 points). Of six hips in stage III, three had received a total hip arthroplasty and three had deteriorated to stage IV (average HHS 73 points).

Adverse tissue reactions to wear particles from Co-alloy articulations, increased by alumina-blasting particle contamination from cementless Ti-based total hip implants. A report of seven revisions with early failure.

We revised seven alumina-blasted cementless hip prostheses (Ti-alloy stems, cp Ti threaded sockets) with low- or high-carbon Co-alloy bearings at a mean of 20.1 months after implantation because of pain and loosening. Histological examination of the retrieved periprosthetic tissues from two cases in which the implant was stable and three in which the socket was loose showed macrophages with basophilic granules containing metal and alumina wear particles and lymph-cell infiltrates. In one of the two cases of stem loosening the thickened neocapsule also contained definite lymphatic follicles and gross lymphocyte/plasma-cell infiltrates. Spectrometric determination of the concentration of elements in periprosthetic tissues from six cases was compared with that of joint capsules from five control patients undergoing primary hip surgery. In the revisions the mean concentration of implant-relevant elements was 693.85 microg/g dry tissue. In addition to Cr (15.2%), Co (4.3%), and Ti (10.3%), Al was predominant (68.1%) and all concentrations were significantly higher (p < 0.001) than those in the control tissues. The annual rates of linear wear were calculated for six implants. The mean value was 11.1 microm (heads 6.25 microm, inserts 4.82 microm). SEM/EDXA showed numerous fine scratches and deep furrows containing alumina particles in loosened sockets, and stems showed contamination with adhering or impacted alumina particles of between 2 and 50 microm in size.

Surgery for hallux valgus. The expectations of patients and surgeons.

Two-hundred patients who had undergone surgery for hallux valgus were interviewed in an attempt to study the different variables which may have contributed to the success of their surgery. These data were compared to the results obtained by using clinically applied scores. To obtain data on surgeons' expectations, 186 members of two national orthopaedic foot societies were interviewed in order to quantify the importance and value of these variables in prognosis. The main interest of the patients is a painless great toe which, when wearing conventional shoes, gives no problems. They also wish to have their bursitis and bunion treated in order to regain their ability to walk as much as they wish. Surgeons are not only specially interested in pain and shoe problems but also in restoring an adequate range of motion in the metatarsophalangeal joint (MTP), removal of the bunion and the treatment of tender callosities. We found that the correction of footwear problems, alleviation of pain and restoration of adequate walking are the most important factors influencing the outcome of surgery. It was surprising that these expectations are only partly revealed by using clinical foot scores.

Chemonucleolysis and automated percutaneous discectomy--a prospective randomized comparison.

In this prospective study 22 patients with painful disc herniations were randomized either to chemonucleolysis (CN) or automated percutaneous discectomy (APD) Preoperatively the Oswestry score was 44 points in the CN group and 41 points in the APD group. Except for a longer duration of preoperative leg pain in the APD group, clinical data were approximately the similar same in the two groups. In the APD group there was one intra-operative complication. Open revision surgery in the same segment was performed once in the CN group and twice in the APD group. Improvement of neurologic deficits and of Owestry score was significant in both groups. At 2 years after surgery the CN treated patients were significantly better with respect to Oswestry score, back pain and leg pain recurrence.

[The value of core decompression in treatment of femur head necrosis]. / Der Stellenwert der Bohrung in der Behandlung der Hüftkopfnekrose.

Core decompression of the necrotic area for treatment of idiopathic osteonecrosis of the femoral head was developed and published by Ficat and Arlet in 1962 within the scope of their "Functional exploration of bone". The mode of action is attributed to a reduction of the intramedullary pressure in the bony compartment of the femoral head. The possibilities of repair and bone regeneration following core decompression are still discussed controversially. Core decompression is a common but not generally accepted procedure in the treatment of idiopathic osteonecrosis of the femoral head. After first publications of positive mid- and long-term effects, some subsequent studies judged it as an ineffective and high-risk method. Analysis of the literature shows that the effectiveness of core decompression depends on the stage of osteonecrosis at the time of surgical intervention. Prognosis is influenced by the extent and location of the necrotic area, the presence and amount of head depression, and continued risk factors--mainly corticoid medication. The best prognosis can be given for patients with a small, medial-centrally located necrosis without head depression. The classification according to Ficat appears to be insufficient, as the extent and localization of the necrotic area are not assessed. Magnetic resonance imaging has become a diagnostic gold standard, as radiographic diagnosis showed poor sensitivity and specificity, especially in the early stages of the disease. As an essential part, MRI was integrated into the new classification of the "Association Internationale de Recherche sur la Circulation Osseuse" (ARCO). On account of the literature and our own experience, treatment by core decompression can be recommended in cases of reversible early stages of osteonecrosis (ARCO 1), as well as in those cases of irreversible early stages (ARCO 2) that show a medial or central location of the necrosis with an extent of less than 30% of the femoral head. Once the disease reaches the irreversible early stage, complete recovery cannot be expected. In these cases only reduction of pain and retardation of the natural course of the osteonecrosis are possible to gain time until total hip replacement is unavoidable.

[Gonarthrosis and empyema in geriatric patients. Combined synovectomy and KTEP implantation procedure]. / Gonarthrose und Empyem bei geriatrischen Patienten. Einzeitiges Vorgehen mit Synovektomie und KTEP-Implantation.

ISSUE: Is a one stage procedures with open synovectomy and implantation of cemented knee endoprostheses in patients with empyemas of the knee and concomitant osteoarthritis suitable to reduce morbidity and increase early mobility? METHOD: Three female patients (age [symbol: see text] 88 yrs.) with acute empyema of arthritic knee joints (Pathogen: Staph. aureus) were treated with open synovectomies and implantations of cemented TKA's in a one stage procedure at mean 3 days (1-6) after admission. After 4.6 months (3-6) we carried out the last clinical and radiographic examination and after 15 months (11-21) a telephone questionnaire. RESULTS: The mean operation time was 2.4 hrs. (2-3), the perioperative blood loss at mean 1040 cc (800-1180 cc) and patients received 4 units blood (4-5). Parenteral antibiotics were administered for at mean 21 days (18-25 d). 33 days (27-39) after surgery the patients could be discharged, all of them ambulated with a walker, the operated joints had no signs of infection and blood parameters i.e. leucocyte count, crp and ESR dropped. At the time of the latest follow up examination there were neither clinical nor radiographic any signs that infections recurred. Two patients ambulated with crutches, one still with a walker. The HSS-Score increased from preop. 54 pts. up to 80 pts. at the follow up. CONCLUSION: Due to our results, a one stage procedure with open synovectomy and implantation of cemented total knee endoprostheses seems to be a considerable alternative for the treatment of geriatric patients suffering from knee empyema and severe osteoarthritis.