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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 145 - 145
1 May 2016
Garcia-Cimbrelo E Garcia-Rey E
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Although cemented fixation provides excellent results in primary total hip replacement (THR), particularly in patients older than 75 years, uncemented implants are most commonly used nowadays. We compare the rate of complications, clinical and radiological results of three different designs over 75-years-old patients.

Materials and Methods

433 hips implanted in patients over 75 years old were identified from our Local Joint Registry. Group A consisted of 139 tapered cemented hips, group B of 140 tapered grit-blasted uncemented hips and group C of 154 tapered porous-coated uncemented hips. A 28 mm femoral head size on polyethylene was used in all cases. The mean age was greater in group A and the physical activity level according to Devane was lower in this group (p<0.001 for both variables). Primary osteoarthritis was the most frequent diagnoses in all groups. The radiological acetabular shape was similar according to Dorr, however, an osteopenic-cylindrical femur was most frequently observed in group A (p<0.001). The pre- and post-operative clinical results were evaluated according to the Merle-D'Aubigne and Postel scale. Radiological cup position was assessed, including hip rotation centre distance according to Ranawat and cup anteversion according to Widmer. We also evaluated the lever arm and height of the greater trochanter distances and the stem position. Kaplan-Meier analysis was done for revision for any cause and loosening.

Results

The hip rotation centre distance was greater and the height of the greater trochanter was lower in group B (p=0.003, p<0.001, respectively). The lever arm distance was lower in group C (p<0.001). A varus stem position was more frequently observed in group B (p<0.001). There were no intra- or post-operative fractures in group A, although there were five intra-operative fractures in the other groups plus two post-operative fractures in group B and four in group C. The rate of dislocation was similar among groups and was the most frequent cause for revision surgery (8 hips for the whole series). The mean post-operative clinical score improved in all groups. The overall survival rate for revision for any cause at 120 months was 88.4% (95% CI 78.8–98), being 97.8% (95% CI 95.2–100) for group A, 81.8% (95% CI 64.8–98.8) for group B and 95.3% (95% CI 91.1–99.6) for group C (log Rank: 0.416). Five hips were revised for loosening. The overall survival rate for loosening at 120 months was 91.9% (95% CI 81.7–100), being 99.2%(95% CI 97.6–100) for group A, 85.5 (95% CI 69.9 −100) for group B and 100% for group C (Log Rank 0.093).


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 5 - 5
1 May 2016
Goto K So K Kuroda Y Okuzu Y Matsuda S
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Background

Composite screws of uncalcined and unsintered hydroxyapatite (HA) particles and poly-l-lactide (PLLA) were developed as completely absorbable bone fixation devices. So far the durability of HA-PLLA composite screws is unclear when used for the fixation of acetabular bone graft in total hip arthroplasty under full-weight conditions. We have used this type of screw for the fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty since 2003. Hence, we conducted a follow-up study to assess the safety and efficacy of these screws when used for cemented socket fixation.

Methods

During 2003–2009, HA-PLLA composite screws were used for fixation of acetabular bone graft in cemented or reverse-hybrid primary THA in 106 patients (114 cases). All the THAs were performed through direct lateral approaches, and postoperative gait exercise with full weight bearing usually started two days after surgery. One patient died of an unrelated disease and seven patients were lost to follow-up within 5 years. Finally, 98 patients (106 cases) were followed up for over 5 years and were reviewed retrospectively (follow-up rate, 93%). Radiographic loosening of the acetabular component was assessed according to the criteria of Hodgkinson et al., and the radiolucent line around the socket was evaluated in all zones, as described by DeLee and Charnley.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_10 | Pages 107 - 107
1 Jun 2018
Schmalzried T
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Loosening is generally the most common reason for revision TKA. In the AOA NJR, the rate of revision varies depending on fixation. Cemented fixation has a lower rate of revision than cementless fixation; 6.7% vs. 8.2% at 14 years. Loosening does occur more frequently in younger patients and in males. Tibial component loosening is the most common. There is an opportunity for improvement. More durable fixation can be achieved through improved cement technique, rather than going cementless. De-bonding of the tibial baseplate from the cement is the mechanism of failure in up to 2.9% of total knee arthroplasties. Among seven surgeons at one center, there was a 6.4 fold range (0.7%-4.5%) in the occurrence of such loosening with the same prosthesis. This surgeon-related variability in tibial component de-bonding indicates that surgical technique influences loosening. In a laboratory study, earlier application of cement to metal increases bond strength (p<0.01) while later application reduces bond strength (p<0.05). Fat contamination of the tibial tray-cement interface reduces bond strength, but application of cement to the underside of the tibial tray prior to insertion substantially mitigates this (p<0.05)


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_10 | Pages 37 - 37
1 Jun 2018
Dorr L
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Dorr bone type is both a qualitative and quantitative classification. Qualitatively on x-rays the cortical thickness determines the ABC type. The cortical thickness is best judged on a lateral x-ray and the focus is on the posterior cortex. In Type A bone it is a thick convex structure (posterior fin of bone) that can force the tip of the tapered implant anteriorly – which then displaces the femoral head posteriorly into relative retroversion. Fractures in DAA hips have had increased fractures in Type A bone because of the metaphyseal-diaphyseal mismatch (metaphysis is bigger than diaphysis in relation to stem size). Quantitatively, Type B bone has osteoclastic erosion of the posterior fin which proceeds from proximal to distal and is characterised by flattening of the fin, and erosive cysts in it from osteoclasts. A tapered stem works well in this bone type, and the bone cells respond positively. Type C bone has loss of the entire posterior fin (stove pipe bone), and the osteoblast function at a low level with dominance of osteoclasts. Type C is also progressive and is worse when both the lateral and AP views show a stove pipe shape. If just the lateral x-ray has thin cortices, and the AP has a tapered thickness of the cortex a non-cemented stem will work, but there is a higher risk for fracture because of weak bone. At surgery Type C bone has “mushy” cancellous bone compared to the hard structure of type A. Tapered stems have high risk for loosening because the diaphysis is bigger than the metaphysis (opposite of Type A). Fully coated rod type stems fix well, but have a high incidence of stress shielding. Cemented fixation is done by surgeons for Type C bone to avoid fracture, and insure a comfortable hip. The large size stem often required to fit Type C bone causes an adverse-stem-bone ratio which can cause chronic thigh pain. I cement patients over age 70 with Type C bone which is most common in women over that age


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_17 | Pages 26 - 26
1 Nov 2016
Schmalzried T
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Loosening is generally the most common reason for revision TKA. In the AOA NJR, the rate of revision varies depending on fixation. Cemented fixation has a lower rate of revision than cementless fixation; 6.7% vs. 8.2% at 14 years. Loosening does occur more frequently in younger patients and in males. Tibial component loosening is the most common. There is an opportunity for improvement. More durable fixation can be achieved through improved cement technique. De-bonding of the tibial baseplate from the cement is the mechanism of failure in up to 2.9% of total knee prostheses. Among seven surgeons at one center, there was a 6.4-fold range (0.7%-4.5%) in the occurrence of such loosening with the same prosthesis. This surgeon-related variability in tibial component de-bonding suggests that surgical technique influences loosening rates. In a laboratory study, earlier application of cement to metal increases bond strength (p<0.01) while later application reduces bond strength (p<0.05). Fat contamination of the tibial tray-cement interface reduces bond strength, but application of cement to the underside of the tibial tray prior to insertion substantially mitigates this (p<0.05)


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_15 | Pages 28 - 28
1 Aug 2017
Lee G
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Total knee arthroplasty (TKA) is reliable, durable, and reproducible in relieving pain and improving function in patients with arthritis of the knee joint. Cemented fixation is the gold standard with low rates of loosening and excellent survivorship in several large clinical series and joint registries. While cementless knee designs have been available for the past 3 decades, changing patient demographics (i.e. younger patients), improved implant designs and materials, and a shift towards TKA procedures being performed in ambulatory surgery centers has rekindled the debate of the role of cementless knee implants in TKA. The drive towards achieving biologic implant fixation in TKA is also driven by the successful transition from cemented hip implants to uncemented THA. However, new technologies and new techniques must be adopted as a result of an unmet need, significant improvement, and/or clinical advantage. Thus, the questions remain: 1) Why switch; and 2) Is cementless TKA more reliable, durable, or reproducible compared to cemented TKA?. There are several advantages to using cement during TKA. First, the technique can be universally applied to all cases without exception and without concerns for bone health or structure. Second, cement can mask imprecisions in bone cuts and is a remarkably durable grout. Third, cement allows for antibiotic delivery at the time surrounding surgery which has been shown in some instances to reduce the risk of subsequent infection. Finally, cement fixation has provided successful and durable fixation across various types knee designs, surface finishes, and articulations. On the other hand, cementless knee implants have had an inconsistent track record throughout history. While some have fared very well, others have exhibited early failures and high revision rates. Behery et al. reported on a series of 70 consecutive cases of cementless TKA matched with 70 cemented TKA cases based on implant design and demographics and found that cementless TKA was associated with a greater risk of aseptic loosening and revision surgery at 5 years follow up. Finally, to date, there has not been a randomised controlled clinical trial demonstrating superiority of cementless fixation compared to cemented fixation in TKA. Improvements in materials and designs have definitely made cementless TKA designs viable. However, concerns with added cost, reproducibility, and durability remain. Cement fixation has withstood the test of time and is not the main cause of TKA failure. Therefore, until there is significant data showing that cementless TKA is more durable, reliable, and reproducible compared to cemented TKA, the widespread use of these implants cannot be recommended


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_III | Pages 90 - 90
1 Feb 2012
Stokes O Al-Hakim W Park D Unwin P Blunn G Pollock R Skinner J Cannon S Briggs T
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Background. Endoprosthetic reconstruction is an established method of treatment for primary bone tumours in children. Traditionally these were implanted with cemented intramedullary fixation. Hydroxyapatite collars at the shoulder of the implant are now standard on all extremity endoprostheses, but older cases were implanted without collars. Uncemented intramedullary fixation with hydroxyapatite collars has also been used in an attempt to reduce the incidence of problems such as aseptic loosening. Currently there are various indications that dictate which method is used. Aims. To establish long term survivorship of cemented versus uncemented endoprosthesis in paediatric patients with primary bone tumours. Methods. This was a retrospective study of 441 endoprostheses implanted in 367 consecutive patients aged 18 years or less, between 1973 and 2005. This included the use of case notes, hospital databases and a radiological review. Information obtained included patient demographics, indications for surgery, anatomical distribution and type of implants, complications and survivorship. Results. Mean age was 13.9 (range 3 - 38). 210 patients were male, 157 were female. There were 364 primaries and 77 revision implants. 161 extendable and 280 definitive prostheses. 282 patients had osteosarcoma, 54 had Ewing's sarcoma and 28 had other diagnoses. Commonest sites included 197 distal femoral replacements, 85 proximal tibial implants and 57 were in the upper limb. Kaplan-Meier survival analysis was used to compare anatomical sites and method of fixation. Upper limb implants had the best long term survival. Failure rates for distal femoral replacements were compared for cemented fixation (21.7% due to aseptic loosening) with cement plus hydroxyapatite collars (3.1%) and uncemented implants with hydroxyapatite collars (6.2%). Conclusions. In the distal femur cemented fixation with hydroxyapatite collars gave the best survivorship in definitive primary prostheses. Uncemented fixation with hydroxyapatite collars gave the best survivorship in extendable prostheses. Cemented fixation without hydroxyapatite gave the worst survivorship


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_28 | Pages 50 - 50
1 Aug 2013
Sampath S Voon H Sangster M Davies H
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Introduction. Total knee arthroplasty has become an established operation. Cemented fixation of the components has given satisfactory results and is accepted as the gold standard. Cement failure with aseptic loosening, however, is a possible long term complication. This is particularly important in view of the increasing number of younger patients who can benefit from this procedure. Hence the attraction of using implants fixed by direct osseointegration of bone into the implant, by passing the potential weak link of the cement. Objectives. The objective of this study was to determine the mid-term clinical, radiological and functional outcomes after navigated cementless and cemented implantation of total knee arthroplasties without patella resurfacing done by a single surgeon. Methods. A mixed patient cohort of 97 consecutive patients who received a navigated e.motion((BBraun Aesculap, Tuttlingen) mobile bearing knee was invited for follow up after a minimum of 5 years. All the procedures were navigated using the Orthopilot(system. The uncemented components were manufactured with a surface coating of plasma sprayed titanium with a pore size between 50 to 200(m to facilitate osteointegration (Plasmapore(). 63 patients followed the invitation and thereof 46 knees were cementless and were reviewed clinically and radiologically. The Knee Society Score (KSS), clinical (KSKS) and functional (KSFS), the Oxford knee score (OKS), complications and revisions were assessed. A radiological determination of potential radiolucencies was done. Results. In the cementless knees, there was a statistically significant improvement in the KSS (KSFS/KSKS) from an average preoperative 74 (36/39) to 185 (90/94) points after an average of 61 months follow-up. The range of motion showed a statistically significant increase from 94° to 110°. The average Oxford score in these patients showed a statistically significant improvement from 45 to 17 points. (p<0.05). All results slightly deteriorated during the period between 2 and 5 years after the index operation. Radiographic examination showed no instances of osteolysis. There were no radiolucent lines adjacent to the femoral implants and none along the coated areas of the tibial implants. For all 97 patients (71 uncemented knees) there was a total of 24(19) complications, 2(2) reoperations and 4(3) revisions. None of the adverse and serious adverse events was prosthesis related. The overall survival rate was 95.9% (cementless: 95.7%). The number of cemented knees was too small for statistical analysis. Conclusion. The Navigated cementless floating platform e.motion total knee replacement gave good clinical and functional results in the medium term. Radiographs showed excellent osteointegration of the implants. These results compared favourably with historical results of both cementless and cemented knees. The survival rate is not significantly different for hybrid (96.1%) and cementless TKA (95.7%) but longer-term follow up results with controls have to be assessed in the future


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_8 | Pages 39 - 39
1 May 2014
Schmalzried T
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The elements of my routine pre-operative planning include skin and scar assessment, the limb length (physical exam and radiographic assessments), the socket type, the stem type, and radiographic templating. Blood management is rarely an issue for primary total hips today and I generally do not recommend pre-operative autologous donation. I currently use a low molecular weight heparin for venous thromboembolic prophylaxis for most all patients. All of my patients have pre-operative medical clearance from a hospital intensivist. A press-fit modular cementless socket is my “workhorse”, although I occasionally use supplemental fixation with spikes (low bone density) or screws (shallow or otherwise deficient hemisphere). Cemented fixation is reserved for hips with radiation necrosis. I use a dual-offset tapered cementless stem in most cases but will use a modular stem in dysplastic, post-traumatic, or severely osteoporotic femurs. I template every case. My goals are to determine component sizes - “the part inside the bone” and improve the biomechanics of the hip – “the part outside the bone”. Sizing is relatively straightforward. For the socket, I use the teardrop and the superior bony edge as landmarks for size and position. I use a Johnson's lateral view radiograph to assess socket version and anterior osteophytes. With a tapered stem, proximal fit on the AP radiograph is the goal and the stem does not need to be canal filling. For the neck resection, I reference off the lesser trochanter. Medialisation of the hip center of rotation (COR) decreases the moment arm for body weight; increasing the femoral off-set lengthens the lever arm for the abductor muscles. These changes in hip biomechanics have a double benefit: a reduction in required abductor forces and lower joint reaction forces. There is accumulating clinical evidence that such favorable alterations in biomechanics can improve clinical outcomes and reduce wear. Higher femoral offset has been associated with greater hip abduction motion and abductor muscle strength. In two independent studies, higher femoral offset has been associated with a significant reduction in polyethylene wear. The traditional arthroplasty goal has been to re-create the offset of the operated hip. In an analysis of 41 patients with one arthritic hip and one clinically and radiographically normal hip (Rolfe et al., 2006 ORS), we found that the horizontal femoral offset of the arthritic hip was, on average, 6mm less than that of the normal, contralateral hip. Considering this, and with medialisation of the COR, is it reasonable to make the femoral offset a few millimeters greater than that pre-op. With modular trial components, final offset and limb-length adjustments are made intra-operatively by assessing soft tissue tension, joint stability and range of motion. Applying these principles in a consecutive series of 40 hips, the hip center of rotation was medialised by 5.6mm and the horizontal femoral offset was increased by an average of 9.5mm, being larger than the normal, contralateral hip by an average of 5.2mm. This combination increased the net biomechanical advantage (NBA) of the diseased hip to an average of 12.5% more than the normal, contralateral hip. The increase in femoral offset is compensated for by medialising the center of rotation. The average lateralisation of the proximal femur of 3.9mm did not cause trochanteric bursitis or other pain. When the offset is right, soft tissue tension can be maintained without over-lengthening. In this series, 2.9mm average lengthening resulted in the reconstructed limb being an average of 1.1mm shorter than the normal side


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_22 | Pages 35 - 35
1 May 2013
Schmalzried T
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The elements of my routine pre-op. planning include skin and scar assessment, the limb length (physical exam and radiographic assessments), the socket type, the stem type, and radiographic templating. Blood management is rarely an issue for primary total hips today and I generally do not recommend pre-operative autologous donation. I currently use a low molecular weight heparin for venous thromboembolic prophylaxis for most all patients. All of my patients have pre-operative medical clearance from a hospital intensivist. A press-fit modular cementless socket is my “workhorse,” although I occasionally use supplemental fixation with spikes (low bone density) or screws (shallow or otherwise deficient hemisphere). Cemented fixation is reserved for hips with radiation necrosis. I use a dual-offset tapered cementless stem in most cases but will use a modular stem in dysplastic, post-traumatic, or severely osteoporotic femurs. I template every case. My goals are to determine component sizes - “the part inside the bone” and improve the biomechanics of the hip – “the part outside the bone”. Sizing is relatively straight forward. For the socket, I use the teardrop and the superior bony edge as landmarks for size and position. I use a Johnson's lateral view radiograph to assess socket version and anterior osteophytes. With a tapered stem, proximal fit on the AP radiograph is the goal and the stem does not need to be canal filling. For the neck resection, I reference off the lesser trochanter. Medialisation of the hip centre of rotation (COR) decreases the moment arm for body weight; increasing the femoral off-set lengthens the lever arm for the abductor muscles. These changes in hip biomechanics have a double benefit: a reduction in required abductor forces and lower joint reaction forces. There is accumulating clinical evidence that such favourable alterations in biomechanics can improve clinical outcomes and reduce wear. Higher femoral off-set has been associated with greater hip abduction motion and abductor muscle strength. In two independent studies, higher femoral off-set has been associated with a significant reduction in polyethylene wear. The traditional arthroplasty goal has been to re-create the off-set of the operated hip. In an analysis of 41 patients with one arthritic hip and one clinically and radiographically normal hip (Rolfe et al., 2006 ORS), we found that the horizontal femoral off-set of the arthritic hip was, on average, 6 mm less than that of the normal, contralateral hip. Considering this, and with medialisation of the COR, is it reasonable to make the femoral off-set a few millimeters greater than that pre-op. With modular trial components, final off-set and limb-length adjustments are made intra-operatively by assessing soft tissue tension, joint stability and range of motion. Applying these principles in a consecutive series of 40 hips, the hip centre of rotation was medialised by 5.6 mm and the horizontal femoral off-set was increased by an average of 9.5 mm, being larger than the normal, contralateral hip by an average of 5.2 mm. This combination increased the net biomechanical advantage of the diseased hip to an average of 12.5% more than the normal, contralateral hip. The increase in femoral off-set is compensated for by medialising the COR. The average lateralisation of the proximal femur of 3.9 mm did not cause trochanteric bursitis or other pain. When the offset is right, soft tissue tension can be maintained without over-lengthening. In this series, 2.9 mm average lengthening resulted in the reconstructed limb being an average of 1.1 mm shorter than the normal side


The Bone & Joint Journal
Vol. 98-B, Issue 1_Supple_A | Pages 31 - 36
1 Jan 2016
Whiteside LA Roy ME Nayfeh TA

Bactericidal levels of antibiotics are difficult to achieve in infected total joint arthroplasty when intravenous antibiotics or antibiotic-loaded cement spacers are used, but intra-articular (IA) delivery of antibiotics has been effective in several studies. This paper describes a protocol for IA delivery of antibiotics in infected knee arthroplasty, and summarises the results of a pharmacokinetic study and two clinical follow-up studies of especially difficult groups: methicillin-resistant Staphylococcus aureus and failed two-stage revision. In the pharmacokinetic study, the mean synovial vancomycin peak level was 9242 (3956 to 32 150; sd 7608 μg/mL) among the 11 patients studied. Serum trough level ranged from 4.2 to 25.2 μg/mL (mean, 12.3 μg/mL; average of 9.6% of the joint trough value), which exceeded minimal inhibitory concentration. The success rate exceeded 95% in the two clinical groups. IA delivery of antibiotics is shown to be safe and effective, and is now the first option for treatment of infected total joint arthroplasty in our institution.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):31–6.