Extracellular matrix metalloproteinases around loose total hip prostheses

We have explored the tissue localization of extracellular matrix metalloproteinases MMP-1 (fibroblast collagenase), MMP-2 (72-kDa gelatinase/Type IV collagenase), MMP-3 (stromelysin), MMP-8 (polymorphonuclear leukocyte collagenase) and MMP-9 (92-kDa gelatinase/Type IV collagenase) in the tissues around loose hip prostheses. The findings were compared with those in synovial tissues obtained from patients with a fractured femoral neck. MMP-type specific antisera were applied in the sensitive avidin-biotin-peroxidase complex methods.

MMP-1 was found in monocyte/macrophages, fibroblasts, and vascular endothelial cells in both interface tissues between bone and acetabular components and the pseudocapsular tissues obtained from loosening of hip prostheses. In these tissues, MMP-8 was occasionally found, but only in polymorphonuclear leukocytes. Cells showing immunoreactivity to 72- and 92-kDa gelatinasenype IV collagenase, MMP-2 and MMP-9, respectively, and stromelysin, MMP-3, were abundant in both interface and pseudocapsular tissues in loose hip prostheses. In contrast, in hip fractures, immunoreactivity to MMP-1, 2, 3, and 9 was weak and only observed in synovial tissues. Immunoreactvity to MMP-8 was confined to polymorphonuclear leukocytes attached to the synovial membrane or in the infiltrate around blood vessels in the subsynovial connective tissues.

The finding of MMP-1, 2, 3, and 9 in the tissues around loose hip prostheses suggests that they play a role in the weakening of connective tissues, and this leads to loosening.     

Factors leading to rearthroplasty in a material with radiographically loose total hip prostheses

The present project was undertaken in an attempt to analyse factors associated with clinical failure (defined as indication for rearthroplasty) of total hip arthroplasties when radiographic loosening of the femoral component was present. Out of 79 radiographically loose femoral components the rate of failure was 23 per cent. High viscosity bone cement was negatively correlated to clinical failure whereas male sex and high body weight was positively correlated to clinical failure. Signs of loosening appearing early in the period of observation significantly more often led to clinical failure than late appearance of loosening, which was encouraging for the long-term prognosis.     

Hydroxyapatite-coated total hip prosthesis. 3d-generation hip prostheses

Since 1987, 80 hydroxyapatite-coated (HA) cementless total hip prostheses have been implanted. Thirty patients were examined 21 months post-operatively and the results compared with data for uncoated prosthesis. Earlier mobilisation and freedom from pain, together with evidence of bone ingrowth without connective tissue membrane formation, confirmed the benefits of HA-coated prostheses.     

Revision total hip arthroplasty. Current role of polymethylmethacrylate

In 29 consecutive failed total hip arthroplasties revised during a 15-month period, cement fixation was used in 14 and cementless fixation in 11. A combination of the two techniques was used in four patients. Analysis of the indications for one or the other fixation type showed that the quality of bone stock and the location of bone deficiency were the most important criteria. The use of a fixation technique that suited the method of bone repair, i.e., autografts, allografts, or a combination of the two, was all-important. Cement technique alone was generally used when bone stock was intact and healthy. Cement was also used in combination with protrusio screens and allografts for gross acetabular deficiencies. Cementless, porous ingrowth technique, together with autografts, was preferred for femoral deficiencies or minor acetabular deficiencies. Bipolar prostheses with compressed, fragmented allografts were used as salvage procedures in gross acetabular deficiencies in older patients, especially when the femoral component did not need to be exchanged.     

Autonomic neuropeptides in the interface membrane of aseptic loose hip prostheses.

We analyzed the presence of autonomic nerve fibers in the interface membranes (n = 9) surrounding aseptic loosened hip prostheses by immunohistochemistry. The study focused on the autonomic messengers neuropeptide Y (NPY), tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of noradrenaline (NA), and vasoactive intestinal polypeptide (VIP). Protein gene product (PGP) 9.5, a general marker of peripheral nerve fibers, was also analyzed to establish the neuronal character of the immunoreactive structures. PGP 9.5-positive and NPY-positive nerve fibers were identified in all 9 samples, and VIP-immunoreactive and TH-immunoreactive fibers were found in 7. There was a difference in the distribution of nerve fibers both between and within the samples. Among the neuropeptides analyzed, NPY was most abundant. NPY-positive and TH-positive fibers were predominantly found around the blood vessel walls forming varicose nerve terminals. VIP-positive fibers were mainly observed as thin varicose nerve terminals with no relationship to blood vessels. Autonomic neuropeptides exert not only vasoactive and immunoregulatory effects, but also have been found to have direct effects on bone tissue. Moreover, the autonomic nervous system has been strongly implicated in nociception and inflammation. Neuronal NPY, TH, and VIP in the interface membrane may prove to contribute to the pathologic mechanisms leading to aseptic loosening of hip prostheses.     

Peri-articular ossification in total hip prostheses

The frequency and predisposing factors of ectopic bone formation (EBF) after total hip arthroplasty (THA) are analyzed in 6026 primary THA documented at the M.E. Mueller Foundation in Berne. Series from two clinics [the Lindenhof Clinic in Berne (n = 816) and the Wilhelm Schulthess Clinic in Zürich (n = 612)] are analyzed separately and the results compared with those in the literature. Overall EBF was found in 38.3% of the patients; in 8.6%, it was clinically obvious (grades III and IV according to the classification of Brooker et al.) and is analyzed in this study. EBF was found in 13.4% of the men compared with 4.2% of the women. The frequency of EBF was found to be particularly low in patients with rheumatoid arthritis (4.4%), and EBF was found in 11.4% of patients with post-traumatic osteoarthritis and in 11.1% with idiopathic necrosis of the femoral head. Severe preoperatively limited hip movement did not significantly increase the risk of EBF (11.9%), nor did previous hip surgery, such as intertrochanteric osteotomy (11.3%). Postoperative hematoma that led to puncture or even evacuation was responsible in 14.4%. The therapeutic and prophylactic possibilities are compared with those in the literature, and our personal observations are discussed.     

Lymphocyte responses in patients with total hip arthroplasty.

How lymphocyte‐mediated metal sensitivity affects orthopaedic implant performance remains poorly understood. Do patients with implants exhibit elevated lymphocyte reactivity to metals and is this reactivity more generalized or more implant‐alloy specific? We investigated these questions by measuring lymphocyte responses to implant metals (Cr⁺³, Co⁺², Ni⁺² at 0.1 mM, and Ti⁺⁴ at 0.001 mM) in six subject groups: Group 1a = young controls, Group 1b = age matched controls, Group 2a = subjects with osteoarthritis (OA) and no history of metal sensitivity, Group 2b = OA subjects with history of metal sensitivity, Group 3a = total hip arthroplasty (THA) subjects with no to mild radiographic osteolysis, and Group 3b = THA subjects with moderate osteolysis. Lymphocyte proliferation, using Lymphocyte Transformation Testing (LTT), and cytokine release provided quantitative reactivity measurement, where a stimulation index of >2 indicated metal sensitivity. OA subjects with a history of metal sensitivity (Group 2b) were more metal reactive to Ni than any other group, as expected (66% incidence and Stimulation Index >20). However, THA subjects (Groups 3a & b) were >3 fold more reactive to Cr (p < 0.04), than were controls (Groups 1a & b) or OA subjects (Groups 2a & b). THA subjects with moderate vs mild osteolysis (Group 3b vs 3a) were more reactive to Co (43% vs 0% incidence). Only osteolytic THA subjects demonstrated increased cytokine responses with >two‐fold (p <0.05) increases in soluble interferon‐γ (IFN‐γ) and interleukin‐2 (IL‐2) levels in response to Cr challenge. This elevated incidence and averaged level of lymphocyte reactivity supports a metal‐specific adaptive immune response and suggests involvement in the pathogenesis of poor implant performance, e.g. aseptic osteolysis. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.     

Intrapelvic migration of total hip prostheses. Operative treatment

We describe a safe operative approach for removal of a prosthesis that has migrated into the pelvis, and we recommend that a two-stage reconstruction be done when revising the total hip-replacement arthroplasty. The first stage consists of the removal of the femoral component and cement through a lateral transtrochanteric approach, followed by removal of the acetabular component through an abdominal-retroperitoneal approach to permit exposure of the major intrapelvic structures and to ascertain their relationship to the acetabular component and cement. After the acetabular component has been removed, bone grafts are applied to the pelvis. Postoperatively, the patient is placed in traction for a time and then is allowed to walk with non-weight-bearing. The second stage of reconstruction, consisting of hip replacement, is performed nine to twelve months after the first stage. A satisfactory result was obtained in the four patients for whom we followed this operative regimen. In one patient, the first-stage procedure yielded a satisfactory result and the second stage was not done.     

Friction couples and total hip prostheses

One of the round tables of the group Futura 2000 at the GECO meeting on 18 January 1999 was devoted to friction couples in total hip prostheses. The discussions were facilitated by the participation of specialists eminent in this field: Professors Sedel and Saillant and Mm Rieker (Société Sulzer), Rack (Société CeramTec), Cales (Société Norton Desmarquest) and Aaron (FHIndustries), to whom we are grateful. We report here on the essence of these discussions.The longterm periprosthetic bony changes are associated with mechanical factors and with biologic factors dominated by the reactions to débris liberated by the prosthesis. Although metal and cement débris contribute to osteolysis, the main factor in bony degradation is the inflammatory reaction to particles of polyethylene [3,4].     

Long-term effects of alumina components in total hip prostheses.

Six pairs of alumina components of Ceraver-Ostéal total hip prostheses, which were implanted from nine to 12 years, were studied. In the load-bearing areas, the wear takes the form of relief polishing. The depth of wear, after a running-in period, is less than 0.3 microns and then reaches an equilibrium. In four cases, there was no displacement of the sockets and wear tracks were formed on the femoral heads, the sockets being worn on their periphery, never on the apex. In the case of two persons weighing more than 90 kg, two wear tracks were observed on the heads, corresponding to walking and raising from a seated position. In the worst case, the depth of the wear track was 44 microns and the weight of alumina debris was estimated to be 18 mg.     

High cathepsin B activity in arthroplasty interface membranes: A histochemical study of 9 loose cemented total hip prostheses

We studied biopsies of interface membranes of 9 aseptically loosened total hip prostheses. The morphologic resemblance of the cement-facing surface of the membranes to synovial tissue of arthritic joints, as noticed by others, was confirmed by histochemical techniques. High cathepsin B activity was found in the bone-facing surface of the membranes. Since this enzyme also plays an important role in tissue destruction of arthritic joints, further similarities in the mechanisms of tissue breakdown in arthritis and aseptic loosening of cemented hip prostheses may be conjectured.     

18F-FDG-PET uptake in non-infected total hip prostheses

Background and purpose — ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) can be used in the diagnostic work-up of a patient with suspected periprosthetic joint infection (PJI) but, due to a lack of accurate interpretation criteria, this technique is not routinely applied. Since the physiological uptake pattern of FDG around a joint prosthesis is not fully elucidated, we determined the physiological FDG uptake in non-infected total hip prostheses.

Patients and methods — Patients treated with primary total hip arthroplasty (1995–2016) who underwent a FDG-PET/CT for an indication other than a suspected PJI were retrospectively evaluated. Scans were both visually and quantitatively analyzed. Semi-quantitative analysis was performed by calculating maximum and peak standardized uptake values (SUV_max and SUV_peak) by volume of interests (VOIs) at 8 different locations around the prosthesis.

Results — 58 scans from 30 patients were analyzed. In most hips, a diffuse heterogeneous uptake pattern around the prosthesis was observed (in 32/38 of the cemented prostheses, and in 16/20 of the uncemented prostheses) and most uptake was located around the neck of the prosthesis. The median SUV_max in the cemented group was 2.66 (95% CI 2.51–3.10) and in the uncemented group 2.87 (CI 2.65–4.63) (Median difference = –0.36 [CI –1.2 to 0.34]). In uncemented prostheses, there was a positive correlation in time between the age of the prosthesis and the FDG uptake (r_s = 0.63 [CI 0.26–0.84]).

Interpretation — Our study provides key data to develop accurate interpretation criteria to differentiate between physiological uptake and infection in patients with a prosthetic joint.     

Disuse osteoporosis in patients with total hip prostheses

Aseptic loosening of total hip arthroplasty is still a serious problem. Bone quality might be one of the major factors influencing loosening. In a previous study, bone loss during the reparation phase was evaluated with modified computed tomography at the site of the implant. The present study documents the degree of disuse osteoporosis prior to and after surgery. Bone density of both tibiae of patients with unilateral artificial hip joints was evaluated longitudinally. Preoperatively a significant right-left difference was found, that has to be attributed to the preoperative unloading of the diseased leg. After surgery a slight but significant bone loss was found in both legs attributable to the immobilization following surgery and the reduced activity in the first 6 months. In successfully operated cases this loss is temporary. In one patient bone loss continued; after 1 year there are now clinical signs of implant loosening. Although the spectrum of physical activity in our group was wide, no correlation between activity and bone loss has been found so far.     

Disuse osteoporosis in patients with total hip prostheses

Summary Aseptic loosening of total hip arthroplasty is still a serious problem. Bone qualitiy might be one of the major factors influencing loosening. In a previous study, bone loss during the reparation phase was evaluated with modified computed tomography at the site of the implant. The present study documents the degree of disuse osteoporosis prior to and after surgery. Bone density of both tibiae of patients with unilateral artificial hip joints was evaluated longitudinally. Preoperatively a significant right-left difference was found, that has to be attributed to the preoperative unloading of the diseased leg. After surgery a slight but significant bone loss was found in both legs attributable to the immobilization following surgery and the reduced activity in the first 6 months. In successfully operated cases this loss is temporary. In one patient bone loss continued; after 1 year there are now clinical signs of implant loosening. Although the spectrum of physical activity in our group was wide, no correlation between activity and bone loss has been found so far.     

The microenvironment around total hip replacement prostheses

The metal stem of the totally replaced hip carries load and resists fatigue, but it is electrochemically corroded. Metallic atoms act as haptens, induce type 1 T-helper cells/Th1-type immune responses and enhance periprosthetic osteolysis. Stiff metal implants, which do not have the same elasticity as the surrounding bone, cause stress shielding. Cyclic loading and lack of ligamentous support lead to mechanical and ischemia reperfusion injury and particle formation from bone, polymethylmethacrylate, and porous implant surfaces, which accelerate third-body polyethylene wear. Surgical injury and micromotion induce the formation of a fibrous capsule interface. Type-B lining cells produce lubricin and surface-active phospholipids to promote solid-to-solid lubrication but may loosen the implant from bone. The pumping action of the cyclically loaded joint and synovial fluid pressure waves dissect the implant-host interface and transports polyethylene particles and pro-inflammatory mediators to the interface. Hyaluronan induces formation of a synovial lining like layer. Because of its localization close to bone, foreign body inflammation at the interface stimulates osteoclastogenesis and peri-implant bone loss. Metal-on-metal and ceramic-on-ceramic pairs might minimize third body wear, but can lead to high-impact load of the acetabulum. Diamond coating of a metal-on-polyethylene couple might solve both of these problems. The basic biomaterial solutions allow good mechanical performance and relatively long life in-service, but surface modifications (porous coating, hydroxyapatite, diamond, bioglass, and others) may facilitate performance of the implant and improve the biomaterial and body interfaces.     

Hydroxyapatite-coated prostheses in total hip and knee arthroplasty

Hydroxyapatite-coated implants have demonstrated extensive bone apposition in animal models. The osseous interface develops even in the presence of gaps of 1 mm and relative motion of up to 500 mum. Development of implant-bone interfacial strength is due to the biological effects of released calcium and phosphate ions, although surface roughness leads to increased interface strength in the absence of interface gaps. The clinical results at fifteen years after total hip replacements have demonstrated that hydroxyapatite-coated femoral stems perform as well as, and possibly better than, other types of cementless devices, with the added benefit of providing a seal against wear debris. Hydroxyapatite-coated acetabular components must have a mechanical interlock with bone in order to take advantage of the coating effects. Clinical analyses of these types of designs at seven years have indicated good survivorship. The performance of a hydroxyapatite-coated implant depends on coating properties (thickness, porosity, hydroxyapatite content, and crystallinity), implant roughness, and overall design. The most reliable predictor of the performance of a device is success in long-term clinical studies.