Aims

The aims of this study were to identify and evaluate the current literature examining the prognostic factors which are associated with failure of total elbow arthroplasty (TEA).

We compared the rate of revision of two classes of primary anatomic shoulder arthroplasty, stemmed (aTSA) and stemless (sTSA) undertaken with cemented all polyethylene glenoid components. A large national arthroplasty registry identified two cohort groups for comparison, aTSA and sTSA between 1. st. January 2011 and 31. st. December 2020. A sub-analysis from 1 January 2017 captured additional patient demographics. The cumulative percentage revision (CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazard models adjusted for age and gender. Of the 7,533 aTSA procedures, the CPR at 8 years was 5.3% and for 2,567 sTSA procedures was 4.0%. There was no difference in the risk of revision between study groups (p=0.128). There was an increased risk of revision for aTSA and sTSA undertaken with humeral head sizes <44mm (p=0.006 and p=0.002 respectively). Low mean surgeon volume (MSV) (<10 cases per annum) was a revision risk for aTSA (p=0.033) but not sTSA (p=0.926). For primary diagnosis osteoarthritis since 2017, low MSV was associated with an increased revision risk for aTSA vs sTSA in the first year (p=0.048). Conversely, low MSV was associated with a decreased revision risk for sTSA in the first 6 months (p<0.001). Predominantly aTSA was revised for loosening (28.8%) and sTSA for instability/dislocation (40.6%). Revision risk of aTSA and sTSA was associated with humeral head size and mean surgeon volume but not patient characteristics. Inexperienced shoulder arthroplasty surgeons experience lower early revision rates with sTSA in the setting of osteoarthritis. Revision of aTSA and sTSA occurred for differing reasons

Abstract. Introduction. Medial fix bearing unicompartmental knee replacement (UKR) designs are consider safe and effective implants with many registries data and big cohort series showing excellent survivorship and clinical outcome comparable to that reported for the most expensive and surgically challenging medial UKR mobile bearing designs. However, whether all polyethylene tibial components (all-poly) provided comparable results to metal-backed modular components during medial fix bearing UKR remains unclear. There have been previous suggestions that all-poly tibia UKR implants might show unacceptable higher rates of early failure due to tibial component early loosening especially in high body max index (BMI) patients. This study aims to find out the short and long-term survival rate of all-poly tibia UKR and its relationship with implant thickness and patient demographics including sex, age, ASA and BMI. Material and Methods. we present the results of a series of 388 medial fixed bearing all-polly tibia UKR done in our institution by a single surgeon between 2007–2019. Results. We found out excellent implant survival with this all-poly tibia UKR design with 5 years survival rate: 96.42%, 7 years survival rate: 95.33%, and 10 years survival rate: 91.87%. Only 1.28% had early revision within 2 years. Conclusion. Fixed bearing medial all-poly tibia UKR shows excellent survivor rate at 2, 5, 7 and 10 years follow up and the survival rate is not related with sex, age, BMI, ASA grade or implant thickness. Contrary to the popular belief, we found out that only 1.71% of all implants was revised due to implant loosening

Aims

Knee arthroplasty surgery is a highly effective treatment for arthritis and disorders of the knee. There are a wide variety of implant brands and types of knee arthroplasty available to surgeons. As a result of a number of highly publicized failures, arthroplasty surgery is highly regulated in the UK and many other countries through national registries, introduced to monitor implant performance, surgeons, and hospitals. With time, the options available within many brand portfolios have grown, with alternative tibial or femoral components, tibial insert materials, or shapes and patella resurfacings. In this study we have investigated the effect of the expansion of implant brand portfolios and where there may be a lack of transparency around a brand name. We also aimed to establish the potential numbers of compatible implant construct combinations.

Aims

The main aims were to identify risk factors predictive of a radiolucent line (RLL) around the acetabular component with an interface bioactive bone cement (IBBC) technique in the first year after THA, and evaluate whether these risk factors influence the development of RLLs at five and ten years after THA.

Aims. The material and design of knee components can have a considerable effect on the contact characteristics of the tibial post. This study aimed to analyze the stress distribution on the tibial post when using different grades of polyethylene for the tibial inserts. In addition, the contact properties of fixed-bearing and mobile-bearing inserts were evaluated. Methods. Three different grades of polyethylene were compared in this study; conventional ultra high molecular weight polyethylene (UHMWPE), highly cross-linked polyethylene (HXLPE), and vitamin E-stabilized polyethylene (VEPE). In addition, tibial baseplates with a fixed-bearing and a mobile-bearing insert were evaluated to understand differences in the contact properties. The inserts were implanted in neutral alignment and with a 10° internal malrotation. The contact stress, von Mises stress, and equivalent plastic strain (PEEQ) on the tibial posts were extracted for comparison. Results. The stress and strain on the tibial post for the three polyethylenes greatly increased when the insert was placed in malrotation, showing a 38% to 56% increase in von Mises stress and a 335% to 434% increase in PEEQ. The VEPE insert had the lowest PEEQ among the three materials. The mobile-bearing design exhibited a lower increase in stress and strain around the tibial posts than the fixed-bearing design. Conclusion. Using VEPE for the tibial component potentially eliminates the risk of material permanent deformation. The mobile-bearing insert can help to avoid a dramatic increase in plastic strain around the tibial post in cases of malrotation. The mobility allows the pressure to be distributed on the tibial post and demonstrated lower stresses with all three polyethylenes simulated. Cite this article: Bone Joint Res 2020;9(11):768–777

The purpose of this investigation is to assess the rate of wear the effect once the “bedding in period”/ poly creep had been eliminated. Creep is the visco-elastic deformation that polyethylene exhibits in the first 6–12 weeks. We also assessed the wear pattern of four different bearing couples in total hip arthroplasty (THA): cobalt-chrome (CoCr) versus oxidized zirconium (OxZir) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) versus highly-crosslinked polyethylene (XLPE) acetabular liners. This was a randomized control study involving 92 patients undergoing THA. They were randomized to one of four bearing couples: (1) CoCr/UHMWPE (n= 23), (2) OxZir/UHMWPE (n=21), (3) CoCr/XLPE (n=24), (4) OxZir/XLPE (n=24). Patients underwent a posterior approach from one of three surgeons involved in the study. All patients received a porous-coated cementless acetabular shell and a cylindrical proximally coated stem with 28 mm femoral heads. Each patient was reviewed clinically and radiographically at six weeks, three and 12 months, two, five and 10 years after surgery. Standardized anteroposterior and lateral radiographs were taken. All polyethylene wear was measured by an independent blinded reviewer. Linear and volumetric wear rates were measured on radiographs using a validated computer software (Polyware Rev. 5). Creep was defined as the wear at 6 or 12 weeks, depending on if there was a more than 10% difference between both measurements. If a greater than 10% difference occurred than the later period's wear would be defined as creep. 72 hips were included in analysis after exclusion of seven revisions, three deaths and 10 losses to follow-up. The annual linear wear rates (in mm/y) at 10 years were (1) 0.249, (2) 0.250, (3) 0.074 and (4) 0.050. After adjusting for creep these rates become were (1) 0.181, (2) 0.142, (3) 0.040 and (4) 0.023. There is statistical differences between raw and adjusted linear wear rates for all bearing couples. The percentage of the radiographically measured wear at 10 years due to creep is (1) 30% (2) 44%, (3) 58.5% and (4) 51.5% with significant differences in couples with XLPE versus those with UHMWPE. There was no significant correlation between age, gender, cup size, tilt, planar anteversion and the linear or volumetric wear rates. The linear wear rate of both UHMWPE and XLPE are even lower thxdsxzan previously described when creep is factored out. XLPE has again demonstrated far superior linear wear rates at 10 years than UHMWPE. There were no significant differences in wear rate at 10 years between CoCr and OxZir, this may be due to an underpowered study. XLPE exhibits proportionally more creep than UHMWPE within the first 6–12 weeks and accounts for more of the total wear at 10 years as measured radiographically at the end period

Aims

Our objective is to describe our early and mid-term results with the use of a new simple primary knee prosthesis as an articulating spacer in planned two-stage management for infected knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a complete two-stage revision.

Aims

To compare long-term survival of all-cemented and hybrid total hip arthroplasty (THA) using the Exeter Universal stem.

Introduction. We have investigated middle-term clinical results of total hip arthroplasty (THA) cemented socket with improved technique using hydroxyapatite (HA) granules. IBBC (interfacial bioactive bone cement method, Oonishi) (1) is an excellent technique for augmenting cement-bone fixation in the long term. However, the technique is difficult and there are concerns over some points, such as bleeding control, disturbance of cement intrusion to anchoring holes by granules, difficulty of the uniform granular dispersion to the acetabular bone. To improve the original technique, we have modified IBBC (M-IBBC), and investigated the middle-term clinical results and radiographic changes. Materials and Methods. K-MAX HS-3 THA (Kyocera, Japan), with tapered cemented stem with small collar and all polyethylene cemented socket, was used for THA implants (Fig.1). Basically the third generation cementing technique was used for THA using bone cement. The socket fixation was performed with bone cement (Endurance, DePuy) and HA granules (Ca10(PO4)6(OH)2, Boneceram P; G-2, 0.3–0.6mm in size, Olympus, Japan) (Fig.2). In original IBBC technique, HA granules were dispersed on reamed acetabulum before cementing. In M-IBBC technique, HA granules were attached to bone cement on plastic plate, then inserted to reamed acetabulum and pressurized (Fig.3). 112 hip joints (95 cases) were operated between June 2010 and March 2014, and followed. The average follow-up period was 6.5 years, and average age at operation was 66.5 years. The clinical results were evaluated by Japan Orthopaedic Association Hip Score (JOA score), and X-p findings were evaluated using antero-posterior radiographs. The locations of radiolucent lines were identified according to the zones described by Delee and Charnley for acetabular components, and Zone 1 was divided into two parts, outer Zone 1a and inner Zone 1b. Results and Discussion. Revision was not performed. JOA score improved from 47 to 88. Socket and stem loosening was not observed. X-p findings of sockets demonstrated radiolucent line in Zone 1a/1b/2/3 in 0.9/0/0/0% immediately after the operation, 6.3/1.8/0/0.9% at 2 years postoperatively. After 2 years there was no progressive change, however, improvement of radiolucent line in Zone 1a was observed in two cases after 3 years postoperatively. Accordingly, at 5 years radiolucent line in Zone 1a/1b was observed in 4.4/1.8%. Oonish has reported excellent clinical results of THA with IBBC (1). To easily perform IBBC, we have modified the technique, improving the problems of IBBC. In this study, radiolucent line was observed at the margin of the socket in a small number of cases, and there was no progressive change. In addition, improvement of radiolucent line was observed in M-IBBC in this study, which was not observed in conventional cementing technique. Conclusions. It is demonstrated that M-IBBC provides stable socket cement fixation for THA. The interesting finding in M-IBBC cases was the improvement of radiolucent line, suggesting osteoconductive property of hydroxyapatite granules at the interface after the operations. The promising long-term clinical results of M-IBBC method, were expected. For any figures or tables, please contact the authors directly

Aims

Limited evidence is available on mid-term outcomes of robotic-arm assisted (RA) partial knee arthroplasty (PKA). Therefore, the purpose of this study was to evaluate mid-term survivorship, modes of failure, and patient-reported outcomes of RA PKA.

Aims

The primary aim of the study was to compare the knee-specific functional outcome of robotic unicompartmental knee arthroplasty (rUKA) with manual total knee arthroplasty (mTKA) for the management of isolated medial compartment osteoarthritis. Secondary aims were to compare length of hospital stay, general health improvement, and satisfaction between rUKA and mTKA.

Two stage exchange has been the gold standard in North America for the treatment of infected knee replacements. The choice of static vs. articulated spacers has been debated for a number of years. At our institution our choice of spacer for 2 stage exchanges is an articulated spacer. This allows motion between stages which facilitates recovery, and makes the second stage technically easier. In a study from our institution we followed 115 infected TKAs treated with the PROSTALAC articulated spacer for 5–9 years. Success for eradication of infection was 88%. With a repeat 2 stage, overall infection control was 98%. In addition, we compared functional outcomes to a group of aseptic knee revisions and found no difference in functional outcomes with standard quality of life outcome scores. While the articulated spacer was our treatment of choice in 2 stage exchange around 2012, the company that manufactured the PROSTALAC knee components ceased to manufacture them. At that time, based on the work of 2 previous studies (Hofmann, Lee), we continued to use articulated spacers. However, this was now the so-called Hofmann technique with a new standard femoral component with an all polyethylene tibia. The only difference from a standard knee revision was no stems and the utilization of high dose antibiotics. We also followed the principles from Europe of one stage exchange, such as wide debridement and soaking in dilute betadine for 15 minutes. More recently as of Sept 2015 we have used an all polyethylene tibia with a keel. The hope being that this will give a more stable tibia than previous and perhaps make a second stage unnecessary. Our first case was September 2015. The intention was not to do a second stage if the infection was eradicated and the patient had good pain relief and function. To date we have implanted 28 of these and in 80% of cases we have not had to do a second stage revision. Further study will reveal where this inadvertent one stage fits in our practi

Total knee replacement (TKA) is one of the most successful procedures in orthopaedic surgery. Although originally limited to more elderly and less active individuals, the inclusion criteria for TKA have changed, with ever younger, more active and heavier patients receiving TKA. This broadening of indications coincided with the widespread adoption of modular cemented and cementless TKA systems in the 1980's, and soon thereafter wear debris related osteolysis and associated prosthetic loosening became major modes of failure for TKA implants of all designs. Initially, tibial components were cemented all polyethylene monoblock constructs. Subsequent long-term follow-up studies of some of these implant designs have demonstrated excellent durability in survivorship studies out to twenty years. While aseptic loosening of these all polyethylene tibial components was a leading cause of failure in these implants, major polyethylene wear-related osteolysis around well-fixed implants was rarely (if ever) observed. Cemented metal-backed nonmodular tibial components were first introduced to allow for improved tibial load distribution and protection of the underlying (often osteoporotic) bone. Eventually, modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80s mainly to facilitate screw fixation for cementless implants. These designs also provided intraoperative versatility by allowing interchange of various polyethylene thicknesses, and also aided the addition of stems and wedges. Modular vs. All Polyethylene Tibial Components in Primary TKA: Kremers et al. reviewed 10,601 adult (>18 years) patients with 14,524 condylar type primary TKA procedures performed at our institution between 1/1/1988 and 12/31/2005 and examined factors effecting outcome. The mean age was 68.7 years and 55% were female. Over an average 9 years follow-up, a total of 865 revisions, including 252 tibia revisions were performed, corresponding to overall survival of 89% (Confidence intervals (CI): 88%, 90%) at 15 years. In comparison to metal modular designs, risk of tibial revision was significantly lower with all polyethylene tibias (HR 0.3, 95% CI: 0.2, 0.5). With any revision as the endpoint, there were no significant differences across the 18 designs examined. Similarly, there were no significant differences across the 18 designs when we considered revisions for aseptic loosening, wear, osteolysis. Among patient characteristics, male gender, younger age, higher BMI were all significantly associated with higher risk of revisions (p<0.008). In a more recent review from our institution of over 11, 600 primary TKA procedures, Houdek et al. again showed that all polyethylene tibial components had superior survivorship vs. metal backed designs, with a lower risk of revision for loosening, osteolysis or component fracture. Furthermore, results for all polyethylene designs were better for all BMI subgroups except for those <25 BMI where there was no difference. All polyethylene results were also better for all age groups except for those under age <55 where there again was no difference. Finally, in a recently published meta-analysis of 28 articles containing data on 95,847 primary TKA procedures, all polyethylene tibial components were associated with a lower risk of revision and adverse outcomes. The available current data support the use of all polyethylene tibial designs in TKA in all patients regardless of age and BMI. In all patients, (not just older individuals) use of an all polyethylene tibial component is an attractive and more cost effective alternative, and is associated with the better survivorship and lower risk of revision than seen with modular metal backed tibial components

Two big problems exist with the all polyethylene cemented tibial component; the polyethylene and the cement. The polyethylene is too weak and flexible to bear high tibial load, so it deforms and loosens. The interface stresses are too high when two flexible structures are poorly bonded and heavily loaded. Modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80's for versatility and to facilitate screw fixation for cementless implants. These designs allow exchange of various polyethylene thicknesses, and aids the addition of stems and wedges. Other advantages include the reduction of inventory, and the potential for isolated tibial polyethylene exchanges as a simpler revision procedure. Several studies have documented the high failure rate of isolated polyethylene exchange procedures, because technical problems related to the original components are left uncorrected. However, revision for wear is the simplest revision ever!. Since the late 1980's the phenomena of polyethylene wear and osteolysis have been observed much more frequently when compared with earlier eras. The reasons for this increased prevalence of synovitis, progressive osteolysis, and severe polyethylene wear remain unclear. There is some association with the widespread use of both cementless and cemented modular tibial designs. Improved polyethylene attachment is the answer even if a screw, a wire, or a pin is needed. Do not abandon the modular tibia

In an effort to address the relatively high rate of glenoid component lucent lines, loosening and failure, tantalum/trabecular metal glenoid implant fixation has evolved as it has in hip and knee arthroplasty. Trabecular metal-anchored glenoid implants used in a consecutive patient case series have demonstrated a lower failure rate than traditional all polyethylene cemented glenoids. Although the radiographs of some patients demonstrated small focal areas of lucency, none have become loose, and only two have actually demonstrated glenoid component failure due to a fracture 6 years after the index procedure. One with glenoid loosening was due to polyethylene wear from a massive cuff tear occurring 8 years after the index procedure. Most patients experienced significant improvements in shoulder range of motion and reduction in pain. Trabecular metal-anchored glenoids when carefully implanted do not produce excessive failure rates, but rather result in functional improvements while decreasing operative time

Introduction. We have investigated the long-term (minimum follow-up period; 10 years) clinical results of the total hip arthroplasty (THA) using K-MAX HS-3 tapered stem. Materials and Methods. In K-MAX HS-3 THA (Kyocera Medical, Kyoto, Japan), cemented titanium alloy stem and all polyethylene cemented socket are used. This stem has the double tapered symmetrical stem design, allowing the rotational stability and uniform stress distribution. The features of this stem are; 1. Vanadium-free high-strength titanium alloy (Ti-15Mo-5Zr-3Al), 2. Double-tapered design, 3. Smooth surface (Ra 0.4µm), 4. Broad proximal profile, 5. Small collar. Previous type stem, which was made of the same smooth-surface titanium alloy, has the design with cylindrical stem tip, allowing the maximum filling of the femoral canal. Osteolysis at the distal end of the stem had been reported in a few cases in previous type with cylindrical stem tip, probably due to the local stress concentration. Therefore the tapered stem was designed, expecting better clinical results. 157 THAs using HS-3 taper type stem were performed at Kitano Hospital between March 2004 and March 2008. And 101 THAs, followed for more than 10 years, were investigated (follow-up rate; 64.3%). The average age of the patients followed at the operation was 61.7 years and the average follow-up period was 10.9 years. The all-polyethylene socket was fixed by bone cement, and the femoral head material was CoCr (22mm; 5 hips, 26 mm; 96 hips). Results. Two hips were revised, one was due to late infection, and the other due to breakage of the implant in trauma. Japanese orthopaedic association (JOA) score improved from 40 to 86 points. Postoperative complication was three periprosthetic fractures (one femoral shaft fracture and two greater trochanteric fractures) and femoral shaft fracture case was operated. Dislocation was not observed. Socket loosening (Hodgkinson, Type 3, 4) and stem loosening (Harris, definite and probable) were not observed radiographically. Cortical hypertrophy was observed in 7.9%. The survival rate of HS-3 tapered stem was 98% for revision due to any reason and 100% for revision due to aseptic loosening. Discussion. The long-term clinical results of K-MAX HS-3 tapered stem were excellent. The osteolysis at the stem tip was not observed in this type, which was observed in a few cases in previous type. From the X-ray finding, it was suggested that this taperd stem had more uniform stress distribution to the femoral bone than previous type. Moreover, the problems associated with titanium alloy usage were not observed. From the present investigation, good farther long-term results of the tapered titanium stem were expected

Stress shielding has been a well-recognised problem with uncemented femoral components resulting in proximal bone loss and dysfunction, but less attention has been paid to the preservation of acetabular bone stock. Uncemented acetabular components often demonstrate reduced bone density on plain radiographs in the mid-portion of the cup (zone 2), which may be due to the rigidity of the outer shell. This study compares the change in bone density around three different cups with varying moduli of elasticity at a minimum of 2 years. Our hypothesis was that less rigid cups would be associated with improved bone density and less stress shielding. This prospective randomised controlled trial compared the bone mineral content (BMC) adjacent to three different cups with marked differences in stiffness. Cup A was an all titanium shell, cup B was a titanium coated all polyethylene implant and cup C was a tantalum backed shell. All articulations used a 32mm ceramic femoral head. Cup B used polyethylene modified by treatment with vitamin E whereas cups A and C used a liner made of irradiated cross linked polyethylene. Five regions of interest (ROI) were established adjacent to the cup, regions 2, 3 and 4 where similar to the DeLee and Charnley regions 1, 2 and 3. Bone density was measured using IDXA preoperatively, postoperatively, 6 months, 1 and 2 years and compared for each ROI and implant. Precision measurements showed significant reliability. All areas showed a reduction in BMC following insertion of the acetabular cup. Bone loss was less in ROI 1 and 4 in the area of rim fit for all cups and the maximal bone loss was seen in ROI 2 and 3 at the dome of the cup. The more elastic cup (Cup B) produced the least bone loss in this area (p<0.05). Cup C produced the largest bone loss at ROI 2 (40%) which continued increasing at 2 years. Cup stiffness is related to bone loss adjacent to the acetabulum, presumably due to a similar process of stress shielding as seen in the femur. All cups produced similar changes at the periphery of the cup but the more elastic cup retained bone density beneath the cup which continued past 2 years. This improvement in bone quality is likely to be associated with better acetabular bone stock into the future and more reliable long term cup fixation