Cemented fixed-bearing PFC total knee arthroplasty: survival and failure analysis at 12-17 years.

BACKGROUND: Total knee arthroplasty (TKA) is the appropriate treatment for degenerative pathology of the knee. Implant surveillance is mandatory to improve clinical results. We present the long-term results of a series of consecutive TKA Press Fit Condylar (J&J), cemented fixed bearing with selective patellar resurfacing in nonselected patients. MATERIALS AND METHODS: In this prospective case series, 223 TKA were clinically and radiographically evaluated using the Hospital for Special Surgery (HSS) knee score and the Knee Society Roentgenographic Evaluation and Scoring System. RESULTS: There were 197 patients, with an average age of 68.4 years [95% confidence interval (CI) 52.7-84.1 years]; 49 arthroplasties were implanted in men (21.1%) and 184 (78.9%) in women. The average follow-up was approximately 13.5 years (162.1 months; 95% CI 132.3-191.9), and it was possible to evaluate 179 implants (76.8% of the implanted prosthesis) in 176 patients. The average HSS score increased from 61.5 (95% CI 60.4-62.7) to 89.4 (95% CI 87.7-.93.5) points. The cumulative average survival rate at 15 years (the endpoint being failure with revision) was 90.6%  ± 2% standard deviation. Resurfacing the patella did not make a difference in terms of implant survival. Progressive radiolucent lines were observed around 20 implants (14.3%); all were revised. CONCLUSIONS: The PFC system is an excellent prosthetic solution. Early clinical complications, mechanical axis and patellar resurfacing do not correlate with implant failure, whereas progressive radiolucent lines do.

The biological reaction to polyethylene wear debris can be related with oxidation of the UHMWPE cups.

BACKGROUND: Oxidised UHMWPE due to gamma irradiation in air has a greater susceptibility to wear than non-oxidised UHMWPE (ethylene oxide, EtO). AIM: To evaluate, the biological reaction of loose implants with oxidised and non-oxidised PE components. MATERIALS AND METHODS: Ten loose PE cups sterilised by EtO (group 1) and 13 sterilised by gamma irradiation in air (group 2) were studied. PE wear and oxidation were related to biological reaction. RESULTS: Group 1: PE cups had low wear score and no oxidation. In the oldest implants, a few PE particles and macrophages were observed in the interface membrane. Group 2: PE inserts had medium-to-high PE wear score and variable oxidation. In the interface membrane, the number and total area of PE particles were high and variable; giant cells were more numerous than macrophages. CONCLUSION: Junctional tissues around loose oxidised PE components contain more PE debris and giant cells than membranes around PE components that are not oxidised.

Rotating knee prosthesis. Surface or hinge replacement?

Until the early 1990's our experience in Total Knee Replacement (TKR) was based on AGC 2000, Tricon M and MG implants. Starting from 1992 we decided to use a rotating knee prosthesis. At that time in Italy there were many knee replacement devices with rotating elements: Oxford, LCS, Rotaglide and Endomodel from Link. The Endomodel rotating prosthesis was our choice and between 1992 and 1995 we implanted 142 prosthesis of this type, 128 as primary replacement and 14 as TKR revision. The overall results were good or excellent in most of our cases (Fig. 1). During this period we had 6 dislocations of the device (Fig. 2) and 4 infections: 1 from our service and 3 coming from other hospitals.

In vivo UHMWPE biodegradation of retrieved prosthesis.

Sixty-two ultra high molecular weight polyethylene prosthetic components (PEs) (31 tibial plateaux and 31 cups), sterilised by gamma rays or ethylene oxide (EtO), were retrieved after 1-12 years depending on different medical reasons and were studied by FTIR spectroscopy with derivatisation of oxidised species. Esters, acids and hydroperoxides were found under the surface of the EtO sterilised PEs up to 2 mm depth. The behaviour of gamma ray sterilised PEs is more complex due to the oxidation following the sterilisation process. Ester and acid formation might arise from the diffusion of components of synovial liquid or from the oxidation process, whereas hydroperoxide formation is thought to be due to the oxidation. Abrasion and delamination process is discussed considering the topological distribution of degradation products.

Oxidation in orthopaedic UHMWPE sterilized by gamma-radiation and ethylene oxide.

Ten new polyethylene prosthetic components (PEs), ethylene oxide (EtO)- and gamma-sterilized, were studied by means of infrared (IR) analysis in order to evaluate oxidation. Using attenuate total reflection infrared spectroscopy the authors demonstrate that all samples show surface oxidation, formed during processing and shaping, related to mechano-degradation. By means of Fourier transform infrared (FTIR) microscopy and derivatization techniques, the EtO-sterilized PEs present different behaviour in comparison to the gamma-radiated. The former show low levels of depth oxidation that could be related to the degradation which occurred during preparation of slices for IR analysis. The gamma-sterilized PEs show higher oxidation levels, variable from sample to sample, on the surface and in the bulk. The authors demonstrate that oxidation is described both by carbonyl species distribution and by hydroperoxide concentration. The hydroperoxides could be responsible for oxidative PEs ageing in in vivo service. The different oxidation levels and distribution could depend on the conditions of gamma-sterilization, in particular on the rate of the dose absorbed, not previously reported for ready-to-implant PEs. Chain scission of gamma-radiated UHMWPE, estimated by IR analysis, results in reduction of molecular weight and consequently in less abrasive resistance. The scheme of UHMWPE oxidation due to gamma-sterilization demonstrates the inhomogeneous distribution of reactive species in PEs responsible for the unpredictable performance in vivo.

Unacceptable biodegradation of polyethylene in vivo.

The chemical characterization of 19 retrieved ultra-high-molecular-weight polyethylene tibial plateaux, six new ones and one raw bar was performed by means of infrared spectroscopy. The surface and bulk oxidation and biodegradation indexes were calculated. The raw bar has a measurable oxidation, which increases on the bulk and on the surfaces of the new plateaux. In the retrieved plateaux, the average oxidation index increases further both on the bulk and on the surfaces; the worse values were present on the worn area. Similar results were found for the biodegradation index. The data show that the biotic in vivo degradation is promoted by the oxidation present on the new plateaux and that it occurs through a different mechanism, abiotic thermal-, photo-, gamma-radiation oxidation, evaluated by the oxidation index.

Thigh pain in cementless hip replacement. Clinical and radiographic correlations.

The authors analyse a series of 35 Rippen System cementless hip joint prostheses implanted in 32 patients from May 1987 to September 1988. Certain radiographic parameters were studied in an attempt to find a correlation with the clinical results. Special attention was paid to the high incidence of thigh pain, attempting to identify the cause through radiographic study of the bone-implant interface. Even when analyzed using Kappa statistics, the correlation between the clinical and radiographic findings was purely incidental. In agreement with the literature, the authors identify some elements which should be investigated further such as primary temporary fixation of the stem, reduction of micromotion, and biocompatibility of the materials.

Extraarticular reconstruction in the treatment of chronic lesions of the anterior cruciate ligament.

The authors report the results of 40 patients treated with Lemaire extraarticular reconstruction for chronic anterior instability of the knee. The rate of success was 80%. The negative results did not have one single explanation, but were caused by either objective or subjective factors depending on the case. In evaluating the results in relation to the follow-up, a deterioration of the good results over time was observed (62.5% after 5 years). The Lemaire reconstruction is recommended for patients over 40 with moderate laxity who occasionally take part in athletic activity.

[Double-contrast arthrography in recurrent luxations of the shoulder]. / L'artrografia a doppio contrasto nella lussazione recidivante della spalla.

One hundred and ninety-three shoulder arthrographies were performed between 1979 and 1985 on patients affected by recurrent dislocations. The diagnostic doubt was cleared up in 162 cases (83%). Arthrographic diagnosis was confirmed by pathological findings in 92% of the patients who underwent surgery. The double-contrast technique under local anaesthesia with anterior access is suggested, since it allows several arthrograms in different projections. Thus, an analytic study of the articular damage can be carried out. The patterns of each projection are briefly shown. Revision of case histories points out that: a) the use of arthrography should always be assessed on a clinical-radiological basis for each patient; b) there is no doubt as to the usefulness of this examination as a direct means of exploration, as far as the articular damage is concerned, not only as an aid to future surgery, but also in the follow-up of the results of the treatment in the long run.

Progressive diaphyseal dysplasia: Camurati-Engelmann's disease.

The authors have studied two cases of progressive diaphyseal dysplasia (Camurati Engelmann's disease). In one case their investigations included bone marrow pressure tests, phlebography and blood gas analysis of the medullary blood. The BMP was raised, and the phlebogram showed venous stasis. The blood gas analysis revealed reduced oxygenation of the medullary blood. On the hypothesis that the vascular change could be of pathogenetic significance, the authors proceeded in both cases to open the medullary canal. This produced immediate remission of the pain, which still persists in one case after six years, while it lasted for three years in the second case.

A critical appraisal of two cases of chondrosarcoma of the pelvis treated by hemipelvectomy.

In presenting two cases of chondrosarcoma of the pelvis treated by hemipelvectomy, the writers discuss the therapeutic possibilities in dealing with this neoplasm at already far advanced stages.

A case of tibial fracture with skin loss and bone infection treated by Papineau's method.

A case of open fracture of the tibia with skin loss and osteitis is reported. It was successfully treated by Papineau's method, which deals with the infection and bone loss before restoring the skin cover.

Etiology, pathogenesis and classifications of knee fractures.

Fractures of the knee include fractures of the lower end of the femur, upper end of tibia, and patella. The term articular fractures has been avoided in this text because it would exclude supracondylar fractures of the femur, fractures of the tibial spines, and epiphyseal separations in which the articular surfaces remain uninjured. By agreement with the other rapporteurs to this Congress, we excluded from our review separation of the apophysis of the tibial tubercle, fractures of the tibial spines, and osteochondral lesions.