Serum aluminium and cobalt levels after ceramic-on-ceramic and metal-on-metal total hip replacement.

In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery. The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 microg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 microg/l (0.25 to 2.3) and the cobalt level was 0.4 microg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 microg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 microg/l (0.25 to 3.9) whereas the cobalt level was 1.4 microg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001). Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

Histopathological Analysis of PEEK Wear Particle Effects on the Synovial Tissue of Patients.

Introduction. Increasing interest developed in the use of carbon-fiber-reinforced-poly-ether-ether-ketones (CFR-PEEK) as an alternative bearing material in knee arthroplasty. The effects of CFR-PEEK wear in in vitro and animal studies are controversially discussed, as there are no data available concerning human tissue. The aim of this study was to analyze human tissue containing CFR-PEEK as well as UHMWPE wear debris. The authors hypothesized no difference between the used biomaterials. Methods and Materials. In 10 patients during knee revision surgery of a rotating-hinge-knee-implant-design, synovial tissue samples were achieved (tibial inserts: UHMWPE; bushings and flanges: CFR-PEEK). One additional patient received revision surgery without any PEEK components as a control. The tissue was paraffin-embedded, sliced into 2 µm thick sections, and stained with hematoxylin and eosin in a standard process. A modified panoptical staining was also done. Results. A "wear-type" reaction was seen in the testing and the control group. In all samples, the UHMWPE particles were scattered in the tissue or incorporated in giant cells. CFR-PEEK particles were seen as conglomerates and only could be found next to vessels. CFR-PEEK particles showed no giant-cell reactions. In conclusion, the hypothesis has to be rejected. UHMWPE and PEEK showed a different scatter-behavior in human synovial tissue.

Review of the outcomes of complex acetabular reconstructions using a stemmed acetabular pedestal component.

AIM: Until now, there has been no consensus as to whether stemmed acetabular components are appropriate for use in patients undergoing revision total hip arthroplasty (THA) who have major acetabular defects or pelvic discontinuity. We wished to address this deficiency in the literature. PATIENTS AND METHODS: We carried out a retrospective study of 35 patients (six men and 29 women) with a mean age of 68 years (37 to 87), with major acetabular defects who underwent revision THA between 2000 and 2012. RESULTS: At a mean follow-up of 63 months (24 to 141), a total of 15 patients (43%) had required at least one further operation. Six implants (17%) loosened aseptically, four (11%) were further revised for infection and two (6%) for technical failure. By taking revision for any reason as the endpoint, the rate of survival of the implant was 61% after five years; by taking revision for aseptic loosening as the end point, it was 78%. The cumulative five-year survival for aseptic loosening was 94% in patients without pelvic discontinuity, and 56% in those with pelvic discontinuity. CONCLUSION: These results indicate a significantly worse survival in patients with pelvic discontinuity (p = 0.020) and we advise caution in the use of the pedestal component in patients with major acetabular defects and pelvic discontinuity who require revision THA. As a result of these findings we have stopped using this implant and prefer to use particulate bone grafts protected with an anti-protrusion cage and posterior column plate fixation, if necessary. TAKE HOME MESSAGE: Based on these poor results, we advise caution if using the pedestal component in patients with major acetabular defects with the presence of a pelvic discontinuity. Cite this article: Bone Joint J 2016;98-B:772-9.

The Impact of Personality Traits on the Outcome of Total Knee Arthroplasty.

Ten to twenty percent of patients with total knee arthroplasty (TKA) are dissatisfied with their clinical outcome. Aim of this study was to investigate the impact of personality traits on the subjective outcome of TKA. We investigated 80 patients with 86 computer navigated TKAs. We asked for patients satisfaction and divided patients into two groups (satisfied or dissatisfied). 12 personality traits were tested by the Freiburg Personality Inventory (FPI-R). Postoperative examination included Knee Society Score (KSS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and the Visual Analogue Scale (VAS). Radiologic investigation was done in all patients. 84% of our patients were satisfied, while 16% were not satisfied. The FPI-R showed statistical significant influence of four personality traits on patient satisfaction: life satisfaction (p = 0.006), performance orientation (p = 0.015), somatic distress (p = 0.001), and emotional stability (p = 0.002). All clinical scores (VAS, WOMAC, and KSS) showed significantly better results in the satisfied patient. Radiological examination showed optimal alignment of all TKAs. There were no complications requiring revision surgery. The results of our study show that personality traits may influence patients satisfaction and clinical outcome after TKA. Therefore patients personality traits may be a useful predictive factor for postoperative satisfaction after TKA.

Function of reinserted abductor muscles after femoral replacement.

We compared two methods of reconstruction of the abductor mechanism in 15 patients after prosthetic replacement of the upper femur, to assess abductor strength and function. Six patients in group I had direct fixation of the gluteus medius tendon and a segment of the original bone to the prosthesis. Nine patients in group 2 had the abductor tendon fixed to the iliotibial band. We assessed clinical function, isometric muscle strength and muscle cross-sectional area for each patient. The patients in group 1 had better clinical and functional results (p = 0.059), with average peak torques for hip abduction of 92% of that in the non-operated leg in group 1, and of 57% in group 2. Group 1 had a mean muscle cross-sectional area of 69% and a mean value of strength per cross-sectional area of 134% when compared with the control side. The respective values for group 2 were 52% and 91%. Direct fixation of the abductor muscles to the prostheses gave improved function and higher isometric abductor muscle force.

Mechanical characteristics of four allograft tendon-to-muscle anastomotic techniques.

Four methods of allograft tendon-to-muscle anastomosis were tested in single cycle distraction to failure using 10 anastomosed ovine calcaneal tendon-biceps brachii units. The tendon-muscle units were compared to intact ovine biceps brachii muscle units. Methods of tendon-to-muscle anastomosis were derived from modifications of existing muscle tendon repair and tenorrhaphy techniques. Load to failure (N), stiffness (N/cm), distraction (cm), and modes of failure were recorded. Of the four methods tested, the side-to-side technique demonstrated the highest load to failure (152.1 N), the greatest stiffness (17.6 N/cm), the least distraction (2.99 cm) before failure, and the least amount of muscle tissue trauma at failure. Results indicate that, of the methods tested, the side-to-side technique offers the greatest initial stability and should therefore allow adequate revascularization and healing of the anastomosis site.

Plantar pressure distribution after resection of the metatarsal heads in rheumatoid arthritis.

Surgical correction of the forefoot in rheumatoid arthritis by resection of all metatarsal heads in combination with a resection arthroplasty of the first metatarsophalangeal joint showed excellent and good results in 20 (77%) of 26 cases and satisfactory and fair results in 6 (23%) of 26 cases. Twenty-six feet in 16 patients were operated on by a plantar approach and examined after a mean follow-up period of 50 months (range, 24-90 months). Seventy-three percent of the patients were free of pain. In 75 (58%) of all 130 investigated toes, complete absence of load distribution was noted. In the remaining 55 (42%) toes, we observed a variable extent of function, depending on the length of resection. Although toe function is better in minimal metatarsal resection, single excessive length or plantar spike formation revealed pressure peaks in the metatarsal area. Metatarsal head resection provided reduction of pain and correction of severe deformities, and permitted the patients to wear ordinary shoes in 24 (93%) of 26 cases.

Primary cementless total hip arthroplasty with second-generation metal-on-metal bearings: a concise follow-up, at a minimum of seventeen years, of a previous report.

BACKGROUND: Second-generation, metal-on-metal bearings were introduced in 1988, to reduce wear and avoid polyethylene particle-induced osteolysis from total hip arthroplasty. In 2007, we reported the long-term results of ninety-eight patients (105 hips) who underwent primary cementless total hip arthroplasty involving the use of a prosthesis with a high-carbide-concentration, metal-on-metal articulating surface between November 1992 and May 1994. The present study gives an update on this patient cohort. METHODS: At a minimum of seventeen years postoperatively, forty-nine patients (fifty-two hips) were available for follow-up examination. We retrospectively evaluated clinical and radiographic results as well as serum metal concentration. The mean patient age at the time of the index arthroplasty was fifty-six years. RESULTS: Three cups (6% of the hips) and one stem (2% of the hips) were revised because of aseptic loosening of the implants combined with focal osteolysis. At the time of the latest follow-up evaluation, the mean Harris hip score was 88.8 points, and the mean University of California Los Angeles (UCLA) activity score was 6.7 points. The cumulative rate of implant survival, with aseptic failure as the end point, was 93.0% at 18.8 years. The median serum cobalt concentration in patients whose hip implant was the only source of cobalt was 0.70 µg/L (range, 0.4 to 5.1 µg/L), showing no increase in the value as noted at a minimum of ten years of follow-up. CONCLUSIONS: The clinical and radiographic results of our study, which, to our knowledge, represent the longest duration of follow-up for a series of cementless total hip arthroplasties with use of a 28-mm metal-on-metal bearing, continue to be comparable with the results observed for other hard-on-hard bearings.

Biotribology of a new bearing material combination in a rotating hinge knee articulation.

The objective of the present study was to evaluate the biotribological behaviour, in terms of wear and particle release, of bushings and flanges made of carbon fibre reinforced poly-ether-ether-ketone (CFR-PEEK) in articulation with a zirconium nitride (ZrN) multilayer surface coating in a rotating hinge knee system. For the bushings of the rotational and flexion axles and the medial and lateral flanges, a CFR-PEEK with 30% polyacrylonitrile fibre content was used in a new bearing combination with ZrN. In vitro wear simulation was performed for patients with metal ion hypersensitivity, using a new rotating hinge knee design with a ZrN surface articulation in comparison with the clinically established cobalt-chromium version. For the bushings and flanges made of CFR-PEEK subjected to wear simulation, the volumetric wear rates were 2.3±0.48mm(3)million(-1) cycles in articulation to cobalt-chromium as reference and 0.21±0.02mm(3)million(-1) cycles in the coupling with ZrN, a 10.9-fold decrease. The released CFR-PEEK particles were comparable in size and shape for the coupling to cobalt-chromium and ZrN with most of the particles in a size range between 0.1 and 2µm. The study reveals comparable low wear and no macroscopic surface fatigue in a new rotating hinge knee design with highly congruent flanges and axles bushings made of CFR-PEEK articulating to a ZrN multilayer surface coating. Favourable wear behaviour of the newly introduced CFR-PEEK/ZrN coupling in comparison with the clinically established CFR-PEEK/cobalt-chromium articulation was found.

STRO-1+ mesenchymal precursor cells located in synovial surface projections of patients with osteoarthritis.

OBJECTIVE: To investigate the presence of mesenchymal precursor cells (MPCs) in synovial surface projections of patients with osteoarthritis (OA), to characterize their phenotype and to show their localization. METHODS: Progenitor cells in synovial surface projections were identified by immunohistochemistry, morphometric analysis and confocal laser scanning microscopy using the following phenotypic markers: STRO-1, CD34, and alpha smooth muscle actin (alpha-SMA). RESULTS: In the synovial tissue of all 21 patients with OA MPCs were detected. Immunohistochemistry and subsequent morphometric analysis showed that approximately twice as many STRO-1+ cells/mm2 were observed in synovial tissue of patients with OA as compared to healthy organ donors and that number of STRO-1+ cells/mm2 correlated with total cell number/mm2. Interestingly, in the synovial tissue of patients with OA, twice as many STRO-1+ cells/mm2 were found in synovial surface projections as compared to the sublining area without villi. Using confocal laser scanning microscopy two populations of STRO-1+ MPCs could be detected in synovial surface projections. Single STRO-1+ cells that co-expressed alpha-SMA resemble a population of pericyte precursors required to stabilize the immature vasculature. The second STRO-1+ cell population that was found lacked alpha-SMA but co-expressed CD34 on their surface with low intensity. CONCLUSION: Here we can show that in the synovial tissue of patients with OA twice as many STRO-1+ MPCs can be found in synovial surface projections as compared to the sublining area. These cells are preferentially located at the basis and in the protruding end of the synovial surface projection.

[Prevention of heterotopic ossification after THA with indomethacin: analysis of risk factors]. / Ossifikationsprophylaxe nach Hüft-TEP mit Indomethacin: Analyse von Risikofaktoren.

AIM: Several risk factors are associated with heterotopic bone formation following total hip replacement. All these risk factors were defined in cohorts without any treatment against postoperative ectopic bone. The aim of this prospective study was to reveal risk factors for the development of postoperative ossifications in patients who underwent a 7-day course of indomethacin therapy. METHODS: 211 consecutive patients with 217 cementless total hip arthroplasties were included. Patients were given 100 mg indomethacin daily in a 7-day course. RESULTS: Grade 2 or 3 ossifications were observed in 13 (5%) of the male and 3 (2%) of the female Individuals postoperatively (p = 0.0043; odds ratio = 0.45). Older individuals (p = 0.0021; odds ratio = 1.03) as well as patients with primary osteoarthritis (p = 0.0307; odds ratio = 0.28) also showed a higher risk for developing ectopic bone formations. CONCLUSION: With a 7-day course of indomethacin after total hip arthroplasty, male and elderly individuals, as well as patients with primary osteoarthritis, are considered to be at high risk to develop heterotopic ossifications postoperatively. Indomethacin reduces the incidence of postoperative ectopic ossifications, but not the patient's risk.

Quantification of axial alignment of the lower extremity on conventional and digital total leg radiographs.

The purpose was to assess axial alignment of the lower limb using mechanical axis measurements on conventional and digital radiographs. Total-leg radiographs of 24 patients, 8 male and 16 female, with a mean age of 68.6+/-10.2 years, were performed in a standardized anterior-posterior projection and standing position using a conventional and digital phosphor storage film screen radiography system. Knee joint angulation was assessed by measuring the angle between a line drawn from the center of the femoral head to the middle of the femoral condyles and a line drawn from the middle of the tibial condyles to the midpoint of the malleolus. On conventional leg radiographs, line drawing and angle measurement were performed manually with a transparent goniometer. Angle measurement on digital leg radiographs was performed on a PACS workstation using computer-assisted measurement software (IMPAX, AGFA-GEVAERT, Belgium). Evaluation time for both measurements was recorded. We diagnosed 14 varus and 10 valgus angulations of the knee joint. The mean individual difference between axis deviation of conventional digital leg radiographs was 0.93+0.6 degrees (min 0 degrees, max 2 degrees), the mean difference in varus angulation was 1.13+/-0.45 degrees (min 0.3 degrees, max 2 degrees), and the mean difference in valgus angulation was 0.65+/-0.71 degrees (min 0 degrees, max 2 degrees). Angle measurements on conventional and digital radiographs did not show any statistically significant difference. Mean time exposure was 4.9 min/patient for manual and 1.08 min/patient for computer-assisted angle measurement (P<0.001). Computer-assisted angle measurement on digital total-leg radiographs represents a reliable method with no significant angle differences compared to conventional radiographic systems and offers a significantly lower evaluation time.

Differences in mesenchymal tissue repair.

Variations in certain mesenchymal tissue healing processes are not widely recognized. The current review summarizes key differences in healing mechanisms and healing potential after injury to soft tissues having different healing outcomes.

[Results following spongiosa transplantation in giant cell tumor of bone]. / Die Ergebnisse nach Spongiosaplastik bei Riesenzelltumoren des Knochens.

Between 1952-1988 47 giant cell tumors of the bone were treated at the Orthopedic University Clinic of Vienna with different surgical margins: In 9 cases a radical or wide, in 3 cases a marginal and in 35 cases an intralesional resection was performed. In the cases with intralesional resections the tumors were diligently curatted and the resulting bone cavity was shaved with a rase. In addition in eleven cases a chemical cauterization was done with phenol. Afterwards the lesion was filled up with autogenous or homogeneous bone chips with or without fibrin tissucol. In the cases where phenol was used no local recurrence was observed over a mean period of 39 months (max. 91, min. 6) of follow up. Because of the subchondral joint location of the giant cell tumors of the extremities a radical or wide resection usually causes the loss of a part of the joint which is followed by poor functional results. Intralesional resections in combination with phenol cauterization not only achieved good functional results, but also succeeded in reducing the rate of local recurrencies from 25-44% in 0 as described by other authors.

[Risk factors for dislocation of a cementless total hip endoprosthesis--a statistical analysis]. / Risikofaktoren für die Luxation einer zementfreien Hüfttotalendoprothese--Eine statistische Analyse.

AIM: This retrospective study aimed at the statistical identification of risk factors for dislocation for a certain cementless hip endoprothesis. MATERIAL AND METHOD: At our department 2605 primary total hip arthroplasties were performed between 1987 and 1997. In 40 patients (1.5%) a dislocation occurred. These patients were compared with a control group matched in number. RESULTS: No difference was found in both groups with respect to age, height, weight, body-mass index, and diagnosis. A tendency was found that more males were involved in the dislocation group. There were more previous operations found in this group (p = 0.005). Also significant was the fact, that patients in the dislocation group more often had epidural anaesthesia (p = 0.02), more often the implantation of the smaller 28-mm head (vs. 32 mm) (p = 0.02), and a higher inclination angle of the acetabular component (p = 0.02). No difference was found in terms of the surgeons experience, the postoperative leg length, femoral offset, medialisation, cranialisation and antetorsion of the acetabular component. CONCLUSION: Dislocation after total hip arthroplasty is a multifactorial complication. With the use of the Alloclassic/Zweymüller total hip endoprothesis, a higher risk for dislocation was found for patients with previous hip surgery, the use of the smaller endoprosthesis head, a high acetabular inclination angle, and in the use of epidural anaesthesia.

The benefits of surgery in the treatment of pelvic metastases.

This retrospective study analyses the benefit of surgery to patients with pelvic metastases. Forty-three patients were operated on between 1980 and 1992, 37 having intralesional and 6 extralesional resections. Thirty-nine had perioperative adjuvant therapy. Survival time was calculated by the Kaplan-Meier method. Clinical evaluation used the Karnofsky performance status which showed improvement from 55% before operation to 74% at 3 months (p = 0.0001) and 77% after 6 months (p = 0.0001). Those having an intralesional resection had a median survival time of 13 months, a complication rate of 24% and a local recurrence rate of 19%. The comparable figures for those with extralesional resection were 16 months survival, complications in 3 out of 6, and no local recurrences. The quality of life was improved by operation and intralesional resection is preferable in most of these patients.

[Systemic diseases and blastomas of the foot]. / Systemerkrankungen und Blastome des Fusses.

Analysis of roentgenograms by location, pattern of destruction, classification of tumor matrix and periosteal new bone formation, together with clinical data, preserves valuable information for discrimination of neoplasms in the foot. Furthermore, specific information on tumor histology and tumor extension in the bone marrow and soft tissues can be obtained by CT and MRI. Preoperative staging, guided biopsy of tumor tissue, monitoring of chemotherapeutic response and postoperative observation are further indications for MRT and other modern imaging modalities.

Biologic attachment of an allograft bone and tendon transplant to a titanium prosthesis.

An Achilles tendon allograft with its bony insertion was used to bridge a Titanium implant, containing an endoprosthetic tendon anchor, and the sheep biceps muscle. Twelve sheep were operated on unilaterally and followed up clinically and histologically for 2, 4 (n = 2), 8, and 12 months (n = 4). Full function of the front limb was regained after 8 to 12 weeks. There were no signs of mechanical loosening at all times. The morphologic changes at the bone block and implant fixation site were an initial revascularization of the allograft bone, which was observed at 2 months and enhanced at 4 months but occurred without any evidence of bone remodeling. This was changed in all specimens taken at 8 and 12 months where intensive new bone development, remodeling, and bone ingrowth in the titanium implant was found. Bone mass was shifted significantly to the tendon insertion half of the bone block because of a creeping substitution of the cancellous allograft bone and bone ingrowth to the implant. Overall bone mass slightly decreased with time but resorption of allograft bone outweighed new bone development only at lesser loaded areas. Transplantation of a bone and tendon allograft to an implant resulted in a revitalized, mechanically stable, and biologically anchored compound.