Background: Knee Osteoarthritis (OA) is a debilitating disease. Initially, the medial compartments are affected in most cases. For this pathology, joint preservation is preferable. Two surgical procedures aim to meet this goal: high-tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA). The aim was to compare clinical and radiological outcomes of HTO versus UKA in patients with unicompartmental, medial OA. Method: Retrospective case series. A total of 86 (61 UKA, 25 HTO) patients that received either treatment at a single, specialized center were assessed pre-operatively and at a single follow-up examination at 77.13 months (±8.170). The Knee Society Score (KSS), range of motion (ROM), SF36 questionnaire and the Tegner score were used. The Kellgren–Lawrence score was assessed pre- and post-surgically. Survivorship with the endpoint “revision” was assessed. Results: The UKA group showed significantly better improvements in KSS scores for pain (p < 0.006) and function (p < 0.001). OA progression (p < 0.02) and survivorship (p < 0.018) differed, significantly favoring UKA. ROM, SF36 and Tegner score did not differ significantly. Conclusions: The presented mid-to long-term data suggest that UKA provides superior results in selected outcomes. Nevertheless, significant differences in the demographics of treatments indicate the challenge of comparing these two treatments.

Bone grafting is commonly used to treat large bone defects. Since autografts are limited and frequently associated with postoperative donor morbidity, allografts from bone banks are often used. However, vascularisation of the allograft is often impaired, resulting in inadequate bone healing and functional graft failure. In bone bank processing, tissue is stored at -80 degree Celsius and subsequently subjected to a harsh multi-step cleaning and sterilisation procedure to prevent immune rejection or transmission of diseases. To determine which step of this procedure diminishes the ability of allografts to induce or promote vascularisation, we used the chick chorioallantoic membrane (CAM) model to monitor the vascular reaction to sample bone chips representing the respective procedural steps. The CAM model monitors the angiogenic potency of xenogeneic and, hence, potentially immunogeneic materials (e.g. cells, tissues, tissue-engineered matrices). Due to the chicken embryo's lack of a fully functional immune system, it provides test conditions that are analogous to immunologically incompetent mice and is a well-suited alternative to their use. Bone chips were placed onto the CAM, and vascular reactions were quantified by image analysis after 48 h incubation. The vascular reaction was most pronounced to fresh, untreated bone chips that had been kept at +2 degree Celsius prior to the experiment. Surprisingly, storage of bone samples at -80 degree Celsius was sufficient to drastically reduce the vascular reaction. Consistent with this, samples representing different stages of the subsequent procedure showed similarly low vascular indices.

Metallosis in total hip arthroplasty (THA) is a not commonly reported complication. We followed 173 consecutive patients, who had received primary, single and non-cemented proximal press fit (PFF) THA with metal-on-metal bearings made of low carbon content in 1995. Follow-up results are available for a total of 161 (93.1%) patients. The mean age of the patients was 63.3 years (31 to 76). The mean duration of follow-up was 94.5 months (range, 57 to 112). The median Harris hip score at follow-up was 95 points. 36 (20.8%) metallosis cases were observed. 18 cases because of metallosis were revised. Dislocation in metallosis cases occurred in 25%. Revisions were obtained because of 2 femur fractures (I with metallosis) and 5 infections. The results with metal-on-metal bearings were not satisfactory. Toxic metal concentrations in joint effusions were found. We do not implant or recommend metal-on-metal bearings in total hip arthroplasty anymore.

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.

We investigated prospectively the bone mineral density (BMD) of the proximal femur after implantation of a tapered rectangular cementless stem in 100 patients with a mean age of 60 years (16 to 87). It was determined using dual energy x-ray absorptiometry, performed one week after surgery and then every six months until the end-point of five years. The BMD increased significantly in Gruen zones 2, 4 and 5 by 11%, 3% and 11% respectively, and decreased significantly in Gruen zones 1, 6 and 7 by 3%, 6% and 14% respectively, over the five-year period. The net mean BMD did not change over this time period. The changes in the BMD were not confined to the first 12 months after surgery. This investigation revealed no change in the overall periprosthetic BMD, but demonstrated a regional redistribution of bone mass from the proximal to distal zones.

Umbilical cord serum and corresponding maternal serum of 3 women with uncemented metal-on-metal total hip arthroplasties were analyzed for cobalt and chromium. The women were an average 3.8 (range, 2-5) years after hip surgery. At the time of delivery, the maternal chromium concentrations were 1.6 microg/l, 0.5 microg/l, and 0.9 microg/l, respectively, and the maternal cobalt concentration was 1 microg/l in the first woman and below the detection limit in the other 2 women. Cobalt and chromium concentrations of the 3 umbilical cord sera also were below the detection limit. This indicates that-with regard to the detection limit of our laboratory-we were unable to observe a passage of cobalt and chromium ions from metal-on-metal articulations across the placenta at the time of delivery.

We investigated whether cup inclination influences serum levels of cobalt and chromium after metal-on-metal total hip arthroplasty. Out of a consecutive series, 3 groups of 20 patients each were established according to their cup inclination: greatest inclination (55 degrees -63 degrees, mean 58 degrees), intermediate inclination (44 degrees -46 degrees, mean 45 degrees), and smallest inclination (23 degrees -37 degrees, mean 33 degrees). We did not detect any statistically significant difference of serum cobalt (P = .23) or serum chromium (P = .13) levels between the 3 groups applying the Kruskal Wallis test. However, 3 patients with cup inclinations of 58 degrees , 63 degrees , and 61 degrees exhibited 9.8-53.6-fold elevated cobalt and 9.5-30.5-fold elevated chromium levels when compared with the median concentrations of this trial. We therefore recommend accurate cup placement also for metal-on-metal articulations.

BACKGROUND:Systemic cobalt dissemination from the Metasul Co-28Cr-6Mo-0.2C metal-on-metal total hip prosthesis has been demonstrated in the first year after implantation. The aim of this prospective study was to monitor the serum cobalt concentrations in patients during the first five years after total hip arthroplasty with a metal-on-metal articulation. METHODS:A total hip arthroplasty was performed without cement in 100 consecutive patients who had either unilateral osteoarthritis or unilateral osteonecrosis. Fifty patients were randomized to be treated with a metal-on-metal articulation, and fifty patients, with a ceramic-on-polyethylene bearing. The femoral stem was made of a Ti-6Al-7Nb alloy, and the threaded acetabular cup was made of commercially pure titanium. Blood samples were taken before the operation and at multiple time-points for five years after the operation. Serum cobalt concentrations were measured with use of atomic absorption spectrometry. RESULTS:In the metal-on-metal group, the median serum cobalt concentration was 1 micro g/L at one year after surgery and 0.7 micro g/L at five years. The median of the serum cobalt concentrations measured from three to twelve months did not differ from the median of subsequent measurements, with the numbers available. The median serum cobalt level in the control group of patients treated with the ceramic-on-polyethylene articulation was below the detection limit at all time-points. CONCLUSIONS:Systemic cobalt release from Metasul metal-on-metal articulations was demonstrated throughout the five-year study period. The median serum cobalt concentrations were found to be slightly above the detection limit and remained in a constant range. The serum cobalt concentrations did not reflect a so-called run-in wear period of the metal-on-metal articulations.

Aim: This prospective study describes This retrospective multicenter study was undertaken to calculate mid- and long-term survival rates of the cementless Zweymuller/Alloclassi(R) total hip prosthesis. Material and Methods: The rectangular titanium stem and threaded cup have been in use since 1986. The ball head is made of alumina ceramic, the inlay of UHMW polyethylene. Five hospitals in Austria, France and Germany cooperated in the follow-up of 848 patients operated between October 1986 and September 1990 (mean age 62.2 years, 62% women, 38% men, mean patient weight 73.8 kg, body mass index 26.8). 468 patients were followed clinically, 320 patients interviewed on the phone, 29 sent a letter. No information was available concerning the remaining 31 patients. Probabilities of implant survival were estimated with the Kaplan-Meier method. Results: 98 patients (11.5%) had died at a median follow-up time of 81.1 months. The probability of survival at 81.1 months was 98.6% looking at stem and cup. There was no significant association of survival of the prosthesis and patient weight, gender or body mass index. Conclusion: Our results are in accordance with previously published data of smaller series using the Zweymuller/Alloclassic(R) total hip. The survival rate of this cementless rectangular titanium prosthesis for the reported follow-up time compares favorably with contemporary cemented hip prostheses.

Aim: This prospective study describes This retrospective multicenter study was undertaken to calculate mid- and long-term survival rates of the cementless Zweymuller/Alloclassic® total hip prosthesis. Material and Methods: The rectangular titanium stem and threaded cup have been in use since 1986. The ball head is made of alumina ceramic, the inlay of UHMW polyethylene. Five hospitals in Austria, France and Germany cooperated in the follow-up of 848 patients operated between October 1986 and September 1990 (mean age 62.2 years, 62% women, 38% men, mean patient weight 73.8 kg, body mass index 26.8). 468 patients were followed clinically, 320 patients interviewed on the phone, 29 sent a letter. No information was available concerning the remaining 31 patients. Probabilities of implant survival were estimated with the Kaplan-Meier method. Results: 98 patients (11.5%) had died at a median follow-up time of 81.1 months. The probability of survival at 81.1 months was 98.6% looking at stem and cup. There was no significant association of survival of the prosthesis and patient weight, gender or body mass index. Conclusion: Our results are in accordance with previously published data of smaller series using the Zweymuller/ Alloclassic® total hip. The survival rate of this cementless rectangular titanium prosthesis for the reported follow-up time compares favorably with contemporary cemented hip prostheses.

Zusammenfassung Die Implantation einer Hüftgelenkprothese ist eine immer häufiger verwendete medizinische Maßnahme bei Erkrankungen des Hüftgelenks wie Koxarthrose, Hüftkopfnekrose, postentzündliche Arthrose oder rheumatoide Arthritis. Von den bildgebenden Methoden ist das konventionelle Röntgen die wichtigste Untersuchung, um den normalen Behandlungsverlauf einer Hüftprothese zu monitieren. Das Röntgen kann frühzeitige Komplikationen wie Fraktur oder Fehlposition intraoperativ oder eine Luxation postoperativ erfassen. Im längerfristigen Verlauf ist das Röntgen zur Diagnose von Infektion, Prothesenlockerung und Weichteilverknöcherung geeignet. In Zusammenschau mit der Klinik ermöglicht die Analyse morphologisch-radiologischer Details, die Wahrscheinlichkeit einer Lockerung abzuschätzen. Bei Protheseninfektionen ermöglicht die MRT die Lokalisation von Weichteilentzündungen. Die Methoden der Bildgebung, besonders das Röntgen, haben in der Beurteilung des normalen und in der Diagnose des komplizierten Verlaufes einen hohen Stellenwert.

Hip arthroplasty has become a common and still increasing procedure for the treatment of osteoarthritis, advanced head necrosis, post-inflammatory arthritis or rheumatoid arthritis. Radiography is the most important imaging modality for monitoring the normal, asymptomatic hip arthroplasty. Radiographs are obtained at the end of a surgical treatment, to exclude complications like fracture or component misplacement. In the follow-up radiographs are used for the diagnosis of loosening and infection of the hip arthroplasty as well as soft tissue ossification. Together with the history and clinical information, the analysis of morphological findings allows to find the grade of loosening. MRI has been advocated in the diagnosis of infection, in particular in the localisation of soft tissue involvement. Imaging, especially by radiographs, is used for the evaluation of the normal and complicated follow-up of hip arthroplasty.

Hip arthroplasty has become a common and still increasing procedure for the treatment of osteoarthritis, advanced head necrosis, post-inflammatory arthritis or rheumatoid arthritis.Radiography is the most important imaging modality for monitoring the normal, asymptomatic hip arthroplasty. Radiographs are obtained at the end of a surgical treatment, to exclude complications like fracture or component misplacement. In the follow-up radiographs are used for the diagnosis of loosening and infection of the hip arthroplasty as well as soft tissue ossification. Together with the history and clinical information, the analysis of morphological findings allows to find the grade of loosening. MRI has been advocated in the diagnosis of infection, in particular in the localisation of soft tissue involvement.Imaging, especially by radiographs, is used for the evaluation of the normal and complicated follow-up of hip arthroplasty.

Background: We report the results of cementless total hip arthroplasty with a tapered, rectangular titanium stem that was introduced in 1979 and continues to be used today with only minor changes. The aim of the design is to achieve primary stability to resist rotational and axial forces through precision rasping and press-fit implantation of a tapered, rectangular femoral component.Methods: Between October 1986 and November 1987, 208 total hip arthroplasties with insertion of a tapered, rectangular titanium stem and a threaded cup without cement were performed in 200 consecutive patients (average age, sixty-one years; range, twenty-two to eighty-four years).Results: At the time of the latest follow-up, fifty-one patients (fifty-two hips) had died and sixteen patients had been lost to follow-up, leaving 133 patients. Twelve hips had been revised, two in patients who subsequently died, leaving 123 living patients without revision. The median follow-up time was 120.7 months. Five cups needed revision surgery because of aseptic loosening; two, because of massive polyethylene wear; one, because of posttraumatic migration; and one, because of breakage. Three femoral stems were revised: one because of malpositioning (the reoperation was done five days after implantation); one, because of infection; and the third, after multiple failed acetabular revisions. The mean Harris hip score for the patients who did not have revision was 85.4 points (range, 46 to 100 points) at the time of the latest follow-up. Four patients (3%) complained of thigh pain that was not associated with another disorder. According to the criteria of Engh et al., all femoral implants were graded as stable bone-ingrown. The probability of survival of both the femoral and the acetabular component at ten years, with any revision as the end point, was 0.92 (95% confidence interval, 0.88 to 0.97). The probability of survival of the cup was 0.93 (95% confidence interval, 0.89 to 0.97), and that of the stem was 0.99 (95% confidence interval, 0.97 to 1.00).Conclusions: The results of arthroplasty with a tapered, rectangular titanium stem combined with a conical threaded cup inserted without cement were excellent at a minimum of ten years. Our data suggest that femoral stem fixation continues to be secure, while the threaded cup is prone to aseptic loosening.

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((R))/Zweymuller total hip endoprthesis, 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.

This retrospective study aimed at the statistical identification of risk factors for dislocation for a certain cementless hip endoprothesis.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.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.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.

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.

We evaluated the effects of aggressive warming and maintenance of normothermia on surgical blood loss and allogeneic transfusion requirement. We randomly assigned 150 patients undergoing total hip arthroplasty with spinal anesthesia to aggressive warming (to maintain a tympanic membrane temperature of 36.5°C) or conventional warming (36°C). Autologous and allogeneic blood were given to maintain a priori designated hematocrits. Blood loss was determined by a blinded investigator based on sponge weight and scavenged cells; postoperative loss was determined from drain output. Results were analyzed on an intention-to-treat basis. Average intraoperative core temperatures were warmer in the patients assigned to aggressive warming (36.5° ± 0.3° vs 36.1° ± 0.3°C, P < 0.001). Mean arterial pressure was similar in each group preoperatively, but was greater intraoperatively in the conventionally warmed patients: 86 ± 12 vs 80 ± 9 mm Hg, P < 0.001. Intraoperative blood loss was significantly greater in the conventional warming (618 mL; interquartile range, 480–864 mL) than the aggressive warming group (488 mL; interquartile range, 368–721 mL;P = 0.002), whereas postoperative blood loss did not differ in the two groups. Total blood loss during surgery and over the first two postoperative days was also significantly greater in the conventional warming group (1678 mL; interquartile range, 1366–1965 mL) than in the aggressively warmed group (1,531 mL; interquartile range, 1055–1746 mL, P = 0.031). A total of 40 conventionally warmed patients required 86 units of allogeneic red blood cells, whereas 29 aggressively warmed patients required 62 units (P = 0.051 and 0.061, respectively). We conclude that aggressive intraoperative warming reduces blood loss during hip arthroplasty. Implications Aggressive warming better maintained core temperature (36.5° vs 36.1°C) and slightly decreased intraoperative blood pressure. Aggressive warming also decreased blood loss by approximately 200 mL. Aggressive warming may thus, be beneficial in patients undergoing hip arthroplasty.

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.

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.