Introduction. The mobile-bearing (MB) total knee arthroplasty (TKA) design was introduced with the aim of reducing polyethylene wear and component loosening seen in the fixed-bearing (FB) design. A recent joint
Multiple joint registries have reported better implant survival for patients aged >75 years undergoing total hip arthroplasty (THA) with cemented implant combinations when compared to hybrid or uncemented implant combinations. However, there is considerable variation within these broad implant categories, and it has therefore been suggested that specific implant combinations should be compared. We analysed the most common contemporary uncemented (Corail/Pinnacle), hybrid (Exeter V40/Trident) and cemented (Exeter V40/Exeter X3) implant combinations in the New Zealand Joint Registry (NZJR) for patients aged >75 years. All THAs performed using the selected implants in the NZJR for patients aged >75 years between 1999 and 2018 were included. Demographic data, implant type, and outcome data including implant survival, reason for revision, and post-operative Oxford Hip Scores were obtained from the NZJR, and detailed survival analyses were performed. Primary outcome was revision for any reason. Reason for revision, including femoral or acetabular failure, and time to revision were recorded. 5427 THAs were included. There were 1105 implantations in the uncemented implant combination group, 3040 in the hybrid implant combination group and 1282 in the cemented implant combination group. Patient reported outcomes were comparable across all groups. Revision rates were comparable between the cemented implant combination (0.31 revisions/100 component years) and the hybrid implant combination (0.40 revisions/100 component years) but were statistically significantly higher in the uncemented implant combination (0.80/100 component years). Femoral-sided revisions were significantly greater in the uncemented implant combination group. The cemented implant and hybrid implant combinations provide equivalent survival and functional outcomes in patients aged over 75 years. Caution is advised if considering use of the uncemented implant combination in this age group, predominantly due to a higher risk of femoral sided revisions. The authors recommend comparison of individual implants rather than broad categories of implants.
A long surgical procedure length has been well associated with worse clinical outcomes, also in an economic climate where in the theatre, time is money, surgical procedures are done very rapidly. Few studies have documented the clinical outcomes of procedure speed. Using the New Zealand Registry we reviewed the operation time of 41,560 primary knee joint replacements. These were split into groups of time slots for the surgery from less than 40 minutes, 40–59, 60–89, 90–119, 120–179 and greater than 180mins. This was referenced to the oxford knee scores obtained and the revision rate. For operations done in less than 40 or greater than 180 minutes, the oxford knee score was lower by 5 years. The revision rate was also increased in these same groups. Operations done in greater than 180 minutes are generally the more complex non-osteoarthrtic and tumour cases and have a higher revision rate reflecting their complexity. Procedures done less than 40 minutes are more straight forward, but there is a relationship shown between this speed and revision rate and poorer outcome. The cause is likely multifactorial, but begs the question, does speed kill?
Obesity is a known risk factor for hip osteoarthritis. The aim of this study was to compare the incidence of obesity in Australians undergoing hip replacements (HR) for osteoarthritis to the general population. A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017-18. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of HR patients by BMI category was compared to the general population, in age and sex sub-groups. During the study period, 32,495 primary HR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher incidence of Class I, II, and III obesity in patients undergoing HR in both sexes aged 35 to 74 years old. Class III obese females and males undergoing HR were on average 6 to 7 years younger than their normal weight counterparts. Class III obese females and males aged 55-64 years old were 2.9 and 1.7 times more likely to undergo HR, respectively (p<0.001). There is a strong association between increased BMI and relative risk of undergoing HR. Similar findings have been noted in the United States of America, Canada, United Kingdom, Sweden and Spain. A New Zealand
Aim. To date, the value of culture results after a debridement, antibiotics and implant retention (DAIR) for early (suspected) prosthetic joint infection (PJI) as risk indicators in terms of prosthesis retention is not clear. At one year follow-up, the relative risk of prosthesis removal was determined for culture-positive and culture-negative DAIRs after primary total hip or knee arthroplasty. The secondary aim was to explore differences in patient characteristics, infection characteristics and outcomes between these two groups. Methods. A retrospective regional
The benefit of using acetabular screws in primary total hip arthroplasty (THA) has been questioned in recent years. The disadvantages of using screws include increased operative time, risk of injury to surrounding neurovascular structures and metal ware breakage. Recent large
Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian
Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian
Introduction. Previous
It is well described that patients with bone and joint infections (BJIs) commonly experience significant functional impairment and disability. Published literature is lacking on the impact of BJIs on mental health. Therefore, the aim of this study was to assess health-related quality of life (HRQoL) and the impact on mental health in patients with BJIs. The AO Trauma Infection Registry is a prospective multinational registry. In total, 229 adult patients with long-bone BJI were enrolled between 1 November 2012 and 31 August 2017 in 18 centres from ten countries. Clinical outcome data, demographic data, and details on infections and treatments were collected. Patient-reported outcomes using the 36-Item Short-Form Health Survey questionnaire (SF-36), Parker Mobility Score, and Katz Index of Independence in Activities of Daily Living were assessed at one, six, and 12 months. The SF-36 mental component subscales were analyzed and correlated with infection characteristics and clinical outcome.Aims
Methods
Periprosthetic infection involving TKR has been projected to rise as the burden of implanted TKR continues to grow. A study by Kurtz et al. found a significant increase in the annual incidence of TKR infection, 2001 (2.05%) to 2.18% in 2009. Thus, deep prosthetic infection around a TKR remains a significant problem that has not been solved, even as technologies improve and the operation is more commonly performed. The economic hospital cost of periprosthetic TKR infection is approximately $100,000 US for a two-stage removal and reimplantation; by the year 2020, it is estimated that 48,000 of these operations will be necessary. The total annual hospital cost for PJI treatment is expected to be over $1 billion by 2020, and does not include the doctor, pharmacologic, and physical therapy fees. Many factors have been found to be associated with an increased risk of PJI. This lecture will focus upon the peri-, intra-, and post-operative factors that have been found historically to carry an increased or decreased risk of infection. Preoperative factors that have been found to affect the risk of infection include: perioperative administration of intravenous antibiotics, patient nutrition, weight, and hemoglobin A1C in diabetic patients. Intraoperative factors include the duration of surgery, the use of antibiotic impregnated cement, and the use of dilute povidone/iodine solution irrigation. Postoperatively, wound care with antimicrobial agents, and a resistance to transfusing blood seem to lower the risk of infection. Yang et al. found that diabetes mellitus carried a 1.6x greater risk of TKR infection, in a meta-analysis of 11 cohort studies. In a
Chronic osteomyelitis (COM) of the lower limb in adults can be surgically managed by either limb reconstruction or amputation. This scoping review aims to map the outcomes used in studies surgically managing COM in order to aid future development of a core outcome set. A total of 11 databases were searched. A subset of studies published between 1 October 2020 and 1 January 2011 from a larger review mapping research on limb reconstruction and limb amputation for the management of lower limb COM were eligible. All outcomes were extracted and recorded verbatim. Outcomes were grouped and categorized as per the revised Williamson and Clarke taxonomy.Aims
Methods
Ceramic-on-ceramic bearings are considered in several European and Asian countries a reliable alternative to metal-on-polyethylene, ceramic-on-polyethylene, or metal-on-metal (with small diameter heads) for total hip arthroplasty (THA) management. Reduced joint wear and limited peri-prosthetic osteolytic changes are the main reasons supporting the use of ceramic. So far, the available observational data show a low rate of revision following the use of Ceramic-on-Ceramic bearings, but concern remains regarding the risk of fracture and the prevalence of squeaking noises from the joint. The objective of this study was to use a national arthroplasty registry to assess whether the choice of bearings – metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM) – is associated with differences in the risk of revision. Data from primary THAs were extracted from the New Zealand Joint Registry over a 15-year period. 97,889 hips were available for analysis. The mean age of patients was 68 years (SD +/− 11 years), and 52% were women. The median followup period in this patient population was 9 years (range, 1 to 15 years). The primary endpoint was revision for any reason. Inclusion criteria were degenerative joint disease (84,894), exclusion criteria were previous surgery, trauma, and any other diagnosis (12,566). We also excluded patients operated on with a Ceramic-on-Metal THA, because of the small recorded number (429). There were 54,409 (64.1%) MoP, 16,503 (19.4%) CoP, 9,051 (10.7%) CoC and 4,931 (5.8%) MoM hip arthroplasties. 3,555 hips were revised during the 15-year observation period. A multivariate assessment was carried out including the following risks factors available for analysis: age, gender, surgeon experience, use of cement. Analysis of bearing surface type and revision showed a statistically significant lower risk for CoC hips (265 THAs, p≤0.01) when compared with CoP (537 THAs, HR 1.07, CI 0,92–1,26), MoP (2186 THAs, HR 1.39, CI 1.19–1,62), and MoM (576 THAs, HR 2.15, CI 1.84–2.51). The 15-year follow-up Kaplan-Meier survival analysis shows a 92% revision-free rate for CoC THAs (Figure 1). In particular, CoC THAs showed the lowest rates of revision for dislocation and for deep infection, when compared with the other bearings. This
Aim. Infection rates after revision THA vary widely, up to 12%. In countries that use antibiotic-loaded cemented stems in combination with perioperative IV antibiotics, infection rates in
Wear of the tibial polyethylene liner of total knee arthroplasty (TKA) is complex and multifactorial. The issues involved include those of implant design and locking mechanism, surgical-technical variability, and patient weight and activity level. However, tibial polyethylene fabrication, including bar stock, amount of irradiation, quenching of free radicals, and sterilization may also be factors in the long-term survival of TKA. Highly crosslinked polyethylene is now widely used in total hip arthroplasty, but its value and use in TKA is a subject of great controversy. In making a decision to use these products, the surgeon should consider multiple sources of evidence: in-vitro wear testing; clinical cohort studies; randomised controlled trials; registry survival data; and retrieval analyses. The two questions to be asked are: is there a value or benefit in the use of these new polyethylenes, and what are the risks involved with the use of these products?. Laboratory testing, generally to 5 million cycles, has shown a significant decrease in tibial polyethylene wear of several products, with both cruciate-retaining and substituting designs, and under adverse conditions. Retrospective cohort studies and RCTs comparing conventional and highly crosslinked polyethylene have shown little difference between the two products at mean follow-up times of 5 years. One
There are numerous examples in medicine where “eminence trumps evidence.” The direct anterior approach (DA) is no exception. Its meteoric rise has largely been driven by industry and surgeon promotion. This surgical approach continues to garner interest, but this interest is largely for marketing purposes, as emerging data would suggest a high risk, low reward operation. In addition, factors such as selection bias and impact bias, have substantially swayed peoples interest into making an inferior operation look better. There are several factors related to the direct anterior approach that should give us pause. Those include the surgeon learning curve, limited functional benefit and increased complications. There is no question the DA approach for total hip arthroplasty (THA) has a long and steep learning curve. The majority of studies would suggest at minimum, 50–100 cases before a surgeon is comfortable with this approach and some studies would suggest the technical difficulties of this approach remain an issue even with increasing experience. This proves difficult with an attempted rapid adoption of this technique by a surgeon who may perform less than 50 THAs per year but feel the need to offer this approach to their patients for marketing purposes. One of the many touted benefits of the DA approach is the perception of improved functional outcomes. Many of the early studies showed early improvement in gait, pain and mobility. However, these studies compared the DA approach to an anterolateral approach. Even when compared to the anterolateral approach, considered the most invasive and least muscle sparing, the benefits of the DA approach were only short term (6 weeks). The majority of retrospective studies, prospective randomised studies and meta-analyses comparing DA to a posterior approach show little, if any, benefit of one approach over another with regards to functional benefit. Another touted benefit includes a low or no dislocation risk associated with the posterior approach. On the contrary many studies have failed to demonstrate lower dislocation rates with the DA approach compared to a contemporary posterior approach. A recent
Background. Patellofemoral complications have dwindled with contemporary total knee designs that market anatomic trochlear grooves that intend to preserve normal patella kinematics. While most reports of patellofemoral complications address patella and its replacement approach, they do not focus on shape of trochlear grooves in different prostheses [1]. The purpose of this study was to characterize 3D geometry of trochlear grooves of contemporary total knee designs (NexGen, Genesis II, Logic, and Attune) defined in terms of sulcus angle and medial-lateral offset with respect to midline of femoral component in coronal view and to compare to those of native femurs derived from 20 osteoarthritic patient CT scans. Materials and Methods. Using 3D models of each implant and native femur, sulcus location and orientation were obtained by fitting a spline to connect sulcus points marked at 90°, 105°, 130°, and 145° of femoral flexion (Fig A). Implant reference plane orientations were established using inner facets of distal and posterior flanges. Reference planes of native femurs were defined using protocols developed by Eckhoff et al. [2] where coronal plane was defined using femoral posterior condyles and greater trochanter. In the coronal plane, a best fit line was used to measure sulcus angle and medial-lateral offset with respect to midline at the base of trochlear groove (Fig B). Results. With exception to Logic (0° sulcus angle & 0 mm offset), contemporary knee designs include high valgus angulations (4° to 18°) with laterally-biased offsets (3 to 5 mm). The native sulcus angle on average was slightly valgus, but varied significantly among the cohort (−0.2° ± 4.6°). Native trochlear groove offset was biased laterally (2.5 ± 1.7 mm). Discussion. We observed a considerable geometric deviation between native femur and implants in terms of sulcus angle while both geometries displayed comparable lateral bias at the base of trochlear groove. Similar to past studies by Iranpour et al. [4] and Feinstein et al. [5], a large variation in sulcus angle was observed among the selected native femurs with an average of small valgus angulation (Fig C). However, most contemporary trochlear grooves are biased towards higher valgus angulations. Retrieval and
The initial application of bone ingrowth technology to the fixation of total knee arthroplasty (TKA) components without bone cement was based on the premise that bone cement was “not biologic”, and so over time would undergo fatigue failure with subsequent loosening. It was hoped that this problem could be obviated by cementless fixation by bone ingrowth, which would remodel over time and not fatigue. In addition, it was anticipated that the failed cementless TKA might be easier to revise and leave the surgeon with more bone to work with. Whether or not cementless fixation of TKA components was justified on any of these counts was uncertain through the first 2 decades of their use. Much of the data accumulated during that period poorly supported these contentions, while cemented TKA was increasingly reported as a reliable, consistent and less complicated form of TKA fixation. However, over the past decade, new evidence has accumulated demonstrating greater success with this technology in several well designed studies as well as from
Metal-on-metal hip arthroplasty has fallen out of favor because of complications arising from the articulation, namely metal sensitivity and accelerated wear. These complications can lead to early/mid-term failures from pain, osteolysis, implant loosening, and pseudotumor formation. However, it has become clearer that MOM total hip arthroplasty behaves differently from MOM hip resurfacing, due to the additional junctions present in the total hip arthroplasty setting. Garbuz et al have demonstrated in a randomised controlled trial that MOM THA has significantly higher metal ion levels than MOM hip resurfacing. Clinical results of a MOM THA compared with a MOM HR using the same articulation also demonstrate significantly poorer results with the THA. Newer literature has also shown that corrosion occurs at the taper junction of a THA due to the dissimilar metals. These corrosion products are likely what are causing a higher incidence of adverse local tissue reactions. Because a hip resurfacing implant is a monoblock ball, there is no taper junction of dissimilar metals that has the potential for corrosion. National
Surgical navigation in joint replacement has been developed for more than 10 years. After the initial enthusiastic period, it appears that few surgeons have included this technology into their routine practice. The reasons for this backflow are lack of evidence of any clinical superiority for navigation implanted prostheses, higher costs and longer operative time. However, navigation systems have evolved, and might still belong to the future of joint replacement. Although most studies did not observe clinically relevant differences between navigated and conventional joint replacement, some
