Objectives- T identify the literature on primary total hip replacement(THR) surgery that is relevant to the question of whether prostheses differ in their medium to longer term outcomes, and to synthesise this evidence. To use evidence regarding both costs and outcomes of primary THR to model how much more effective newer prostheses must be to justify higher costs

Primary total hip replacement surgery: a systematic review of outcomes and modelling of cost-effectiveness associated with different prostheses.

The clinical use of plasma-sprayed hydroxyapatite (HA) coatings on metal implants has aroused as many controversies as interests over the last decade. Although faster and stronger fixation and more bone growth have been revealed, the performance of HA-coated implants has been doubted. This article will initially address the fundamentals of the material selection, design, and processing of the HA coating and show how the coating microstructure and properties can be a good predictor of the expected behavior in the body. Further discussion will clarify the major concerns with the clinical use of HA coatings and introduce a comprehensive review concerning the outcomes experienced with respect to clinical practice over the past 5 years. A reflection on the results indicates that HA coatings can promote earlier and stronger fixation but exhibit a durability that can be related to the coating quality. Specific relationships between coating quality and clinical performance are being established as characterization methods disclose more information about the coating.

Material fundamentals and clinical performance of plasma-sprayed hydroxyapatite coatings: A review

Recent studies have generated considerable information that reveals substantial support for major change in the understanding of total hip arthroplasty and its current state. Although some of these observations appear unrelated at first glance, they can be drawn together to support the thesis that osteolysis is the dominant problem in total hip arthroplasty. These observations are as follows: (1) Five-year followup data are required for a minimum assessment of a new concept in total hip design and material because osteolysis is uncommon before that time. (2) Excellent fixation can be achieved on the femoral side with good cementing and good cementless techniques. Thus, femoral component loosening is less of an issue currently. (3) Many acetabular components become loose because of the ingress of particulate debris that leads to linear bone loss at the interface with the pelvis, a process that is biologically akin to the more florid forms of osteolysis. Thus, much acetabular component loosening represents a form of osteolysis. (4) Many cementless femoral reconstructions have developed a high incidence of femoral osteolysis. (5) Many cementless sockets have developed a high incidence of pelvic osteolysis. Taken in conjunction, these observations suggest that periprosthetic osteolysis is the leading problem in contemporary total hip replacement.

The problem is osteolysis

We present the 5.6- to 7.6-year results of our first 118 hydroxyapatite (HA)-coated total hip replacements in patients under 66 years of age. The titanium femoral component has proximal HA coating and was usually articulated with an HA-coated threaded cup. The HA coating of 50 microns thickness has a porosity of below 3%, 97% HA purity and 65% crystallinity. The survival rate at a mean of six years was 100% for the HA-coated stems and 99% for the HA-threaded cups. The average Harris hip score at one year was 96, and at three years and thereafter 98. There was a very low incidence of early pain after surgery. Serial radiographs showed rapid bony integration of implants with evidence of bone apposition on the coating within six months. By Engh's criteria, all the femoral components had confirmed bone ongrowth after three years. We found no deterioration of results with time, and consider that our clinical and radiological results show that HA coatings can provide early pain relief and durable implant fixation.

Six-year results of hydroxyapatite-coated total hip replacement.

Much can be learned from a careful reassessment of the history of total hip replacement over the past 35 years. Such a review is revealing about certain aspects of the nature of medical science, and most importantly, about solving our current problems in total hip replacement, notably cementless surgery with the rapidly increasing incidence of major pelvic and femoral lysis, predominantly manifest after 5 years or so postoperatively.

https://www.tandfonline.com/doi/pdf/10.3109/17453679408993734

Osteolysis and particle disease in hip replacement. A review

We studied 108 patients (116 hips) who were followed for a minimum of six years (73 to 89 months) after primary total hip arthroplasty using an uncemented porous-coated anatomic hip. The average age of the patients at operation was 48.4 years, and the diagnosis was avascular necrosis of the femoral head in 46 hips, neglected femoral neck fracture in 27, osteoarthritis secondary to childhood pyogenic arthritis in 24 and to childhood tuberculous arthritis in five, and miscellaneous in 14. The average preoperative Harris hip score was 55, which improved to 91 at latest follow-up. All patients with loose femoral components or disabling thigh pain had received prostheses which were undersized in the coronal or the sagittal plane, or in both. No patient with a satisfactory fit in both coronal and sagittal planes had loosening of the femoral component or disabling thigh pain. Three acetabular components showed aseptic loosening and 20 showed excessive wear (5 to 11 mm) of the polyethylene liner. Excessive wear was related to young age, but not to body-weight, gender, primary diagnosis, hip score, or range of hip movement. There was a high incidence of osteolysis (38 of 116 hips, 33%). We recommend careful preoperative planning, with the use of a contemporary cemented technique when a satisfactory fit cannot be obtained. The high incidence of excessive wear and of osteolysis needs further investigation.

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Uncemented porous-coated anatomic total hip replacement. Results at six years in a consecutive series.

We reviewed 82 primary arthroplasties (in 71 patients) in which cementless porous-coated hip prostheses were used. The mean age of the patients at operation was 52 years (24 to 86); they were followed up for an average of 62.1 months (60 to 66). The diagnosis was avascular necrosis of the femoral head in 35%, fracture of the femoral neck in 24%, primary osteoarthritis in 16% and miscellaneous in 25%. The average preoperative Harris hip score was 56.7 points and the average postoperative score was 83.3 points. Eight hips (10%) had component loosening; four had been revised and four were awaiting revision. In 27 hips (33%) there was a radiolucent line wider than 2 mm in zones 1 and 7. In 55 hips (67%) there was calcar resorption of more than 10 mm. Twenty patients (28%) complained of thigh pain although they had no radiographic evidence of loosening of a component. Factors that may have contributed to the poor clinical and radiographic results were: 1) inadequate surface area for bone ingrowth, particularly on the lateral aspect of the upper part of the prosthesis, 2) poor initial fit of the stem in the metaphysis, which resulted in cantilever motion of the proximal part of the stem about the well-fixed distal stem, and 3) the collar of the prosthesis, which prevented it from subsiding to a naturally stable position and caused damage to the calcar.

Results of the Harris-Galante cementless hip prosthesis.

Primary total hip arthroplasties were performed in 108 patients (116 hips) using a porous coated anatomic (PCA) hip system. Nineteen (22 hips) of 108 patients (116 hips) who had a subsidence of a PCA femoral stem more than 3 mm were studied for the time onset, the amount of stem subsidence, and outcomes. A minimum follow-up period was seven years. The average age of the patients at operation was 37.4 years. The operative diagnosis was avascular necrosis of femoral head in seven hips; osteoarthrosis secondary to childhood septic hip joint in six; fracture of femoral neck in three; and miscellaneous in six hips. The average preoperative Harris hip score was 57 points, which improved to 82 points at the seven-year follow-up examination. Overall, there was a 79% prevalence of thigh pain (15 patients). Six patients had occasional, nondisabling, activity-related thigh pain. The remaining nine patients had persistent and disabling thigh pain at the final follow-up examination. All stems had an undersized component in one or both planes. One hip was stabilized by bone ingrowth. Twelve hips were fixed by fibrous tissue ingrowth and had occasional clinical symptoms. Nine hips had component loosening at the final follow-up examination, of which four were revised and five were pending revision. Early instability of the femoral component measured by radiographs was correlated with and predictive of late radiographic loosening of the femoral component.

Early migration of uncemented porous coated anatomic femoral component related to aseptic loosening.

The authors studied 50 consecutive and nonselected patients (52 hips) who were followed for a minimum of 7 years (range, 84–89 months) after they had a primary total hip arthroplasty with an uncemented Anatomic Medullary Locking (DePuy, Warsaw, IN) hip system. The average age of the patients at operation was 47.6 years (range, 19–88 years). The operative diagnoses were: avascular necrosis of the femoral head in 18 hips (34%), osteoarthritis in 16 (31%), fracture of the femoral neck in 14 (27%), and miscellaneous in 4 (8%). The average preoperative Harris hip score was 59 points (range, 6–67 points) that improved to 91 points (range, 69–100 points) at the 7-year follow-up examination. To assess the adequacy of intramedullary fit, the fit of the stem at the proximal canal and isthmus level was evaluated. Forty-one hips (79%) had a good press-fit at both the proximal canal and isthmus level, five hips (10%) had a good press-fit at the proximal canal only, and the remaining six hips (11%) had a poor fit at both the proximal canal and isthmus level. Of the 46 hips that had a good press-fit at the proximal canal and/or isthmus level or proximal canal only, 32 (70%) had bone ingrowth and 14 (30%) had stable fibrous tissue ingrowth. Of the remaining six hips with a poor press-fit at both the proximal canal and isthmus level, three (6%) had stable fibrous tissue ingrowth and another three (6%) were unstable. Of the three hips (6%) with femoral component loosening, one was revised and the other two were asymptomatic. There was an alarmingly high incidence of perioprosthetic osteolysis in our series: 16 hips (31%) had acetabular and femoral osteolysis and 13 hips (25%) had femoral osteolysis only. Also, there was a strikingly high incidence of polyethylene-liner wear (12 hips or 23%). Although the incidence of component loosening was low, a high incidence of periprosthetic osteolysis and excessive wear in the polyethylene liner remain challenging problems after insertion of the cementless Anatomic Medullary Locking prosthesis.

Cementless porous-coated anatomic medullary locking total hip prostheses.

Factors contributing to deep vein thrombosis (DVT) were studied in 51 patients (62 knees) who had a cementless total knee arthroplasty (TKA) and in 51 patients (69 knees) who had a cemented TKA. All patients were treated with a primary TKA using a porous-coated anatomic prosthesis with a porous-coated central tibial stem. Deep vein thrombosis was diagnosed by roentgenographic venography, and pulmonary embolism was diagnosed by perfusion lung scanning. Incidence of DVT was 32%, and there was no pulmonary embolism. The factors that do not seem to have much relevancy to DVT were advanced age, orthopedic disease, one- or two-staged bilateral TKA, venous anatomic variations, number of venous valves, coagulation assay data, hypertension, tourniquet time, choice of cementless or cemented TKA, severity or duration of operation, amount of blood loss, and amount of blood transfused. Conversely, more immediate relevant factors were obesity, postoperative prolonged immobilization, earlier venous disease, and hyperlipidemia.

Vana E. M. Kim

Papers

Uncemented porous-coated anatomic total hip replacement. Results at six years in a consecutive series.

Results of the Harris-Galante cementless hip prosthesis.

Early migration of uncemented porous coated anatomic femoral component related to aseptic loosening.

Cementless porous-coated anatomic medullary locking total hip prostheses.

Factors leading to low incidence of deep vein thrombosis after cementless and cemented total knee arthroplasty.