Femoral Cementation in Knee Arthroplasty-A Comparison of Three Cementing Techniques in a Sawbone Model Using the ATTUNE Knee.

Femoral component loosening is a rare but severe complication in total knee arthroplasty. Former studies have repeatedly demonstrated radiolucent lines behind the ventral and dorsal anchoring shields of the femoral components, which has led us to investigate this matter further. Therefore, three different cementing techniques were tested in a group of nine Sawbone samples each. These differed in the amount of cement applied on the femoral component as well as in the pressure application. Computed tomography was performed to evaluate and classify the cement penetration into the bone adjacent to the prosthesis according to the zones defined by the Knee Society scoring system. The results show significantly deeper cement penetration in all zones when a pressurizer is used. In the other two groups, no significant difference in the dorsal bevel cement penetration was noted. Additionally, no difference in ventral and dorsal cement penetrations (Zones 1 and 4) was delineated. In contrast, there was a significant difference in both the ventral bevel (Zone 2) as well as the distal anchoring surface (Zones 5-7). The use of a pressurizer results in greater cement penetration into all anchoring areas. Completely covering the component back surface results in a significantly higher penetration, which is mainly due to differences in volume. These data show significantly improved cementation results when using a pressurizer. Whether this improves the biomechanical properties and ultimately the revision rate requires further investigation.

Comparison of the stability of three fixation techniques between porous metal acetabular components and augments.

OBJECTIVES: In order to address acetabular defects, porous metal revision acetabular components and augments have been developed, which require fixation to each other. The fixation technique that results in the smallest relative movement between the components, as well as its influence on the primary stability with the host bone, have not previously been determined. METHODS: A total of 18 composite hemipelvises with a Paprosky IIB defect were implanted using a porous titanium 56 mm multihole acetabular component and 1 cm augment. Each acetabular component and augment was affixed to the bone using two screws, while the method of fixation between the acetabular component and augment varied for the three groups of six hemipelvises: group S, screw fixation only; group SC, screw plus cement fixation; group C, cement fixation only. The implanted hemipelvises were cyclically loaded to three different loading maxima (0.5 kN, 0.9 kN, and 1.8 kN). RESULTS: Screw fixation alone resulted in up to three times more movement (p = 0.006), especially when load was increased to 100% (p < 0.001), than with the other two fixation methods (C and SC). No significant difference was noted when a screw was added to the cement fixation. Increased load resulted in increased relative movement between the interfaces in all fixation methods (p < 0.001). CONCLUSION: Cement fixation between a porous titanium acetabular component and augment is associated with less relative movement than screw fixation alone for all implant interfaces, particularly with increasing loads. Adding a screw to the cement fixation did not offer any significant advantage. These results also show that the stability of the tested acetabular component/augment interface affects the stability of the construct that is affixed to the bone.Cite this article: N. A. Beckmann, R. G. Bitsch, M. Gondan, M. Schonhoff, S. Jaeger. Comparison of the stability of three fixation techniques between porous metal acetabular components and augments. Bone Joint Res 2018;7:282-288. DOI: 10.1302/2046-3758.74.BJR-2017-0198.R1.

Femoral rotation in total knee arthroplasty: a comparison of patient individualized jigs with gap balancing in relation to anatomic landmarks.

PURPOSE: The purpose of our study was to compare the accuracy of the rotational position of the femoral component in total knee arthroplasty aligned with patient individualized jigs (PSJ) to a gap balancing technique (GBT). METHODS: A consecutive series of 21 osteoarthritic patients were treated with 22 cruciate-retaining total knee prostheses. During surgery, the rotation of the femoral component pinholes was recorded for all knees using PSJ and GBT and transferred to computer tomograms (CT). The rotational differences between PSJ and GBT relative to the transepicondylar axis were analysed. RESULTS: The medium rotation of the femoral component pinholes was 1.3° ± 5.1° (min = -6.3°; max = 14.4°) for PSJ and 0.1 ± 1.4° (min = -1.6°; max = 3.4°) for GBT. Outliers of more than 3° were found more frequently with PSJ in 12 cases but only in one for GBT. CONCLUSION: Based on our study, we would not recommend relying intra-operatively solely on the CT-based PSJ without the option to adjust or control femoral rotation. LEVEL OF EVIDENCE: II.

Increased antibiotic release and equivalent biomechanics of a spacer cement without hard radio contrast agents.

We compared a novel calcium carbonate spacer cement (Copal® spacem) to well-established bone cements. Electron microscopic structure and elution properties of the antibiotics ofloxacin, vancomycin, clindamycin, and gentamicin were examined. A knee wear simulator model for articulating cement spacers was established. Mechanical tests for bending strength, flexural modulus, and compressive and fatigue strength were performed. The electron microscopic analysis showed a microporous structure of the spacer cement, and this promoted a significantly higher and longer antibiotic elution. All spacer cement specimens released the antibiotics for a period of up to 50days with the exception of the vancomycin loading. The spacer cement showed significantly less wear scars and fulfilled the ISO 5833 requirements. The newly developed spacer cement is a hydrophilic antibiotic carrier with an increased release. Cement without hard radio contrast agents can improve tribological behaviour of spacers, and this may reduce reactive wear particles and abrasive bone defects.

The stability of the femoral component in the Oxford unicompartmental knee replacement: a comparison of single and twin peg designs.

Aseptic loosening of the femoral component is an important indication for revision surgery in unicompartmental knee replacement (UKR). A new design of femoral component with an additional peg was introduced for the cemented Oxford UKR to increase its stability. The purpose of this study was to compare the primary stability of the two designs of component. Medial Oxford UKR was performed in 12 pairs of human cadaver knees. In each pair, one knee received the single peg and one received the twin peg design. Three dimensional micromotion and subsidence of the component in relation to the bone was measured under cyclical loading at flexion of 40° and 70° using an optical measuring system. Wilcoxon matched pairs signed-rank test was performed to detect differences between the two groups. There was no significant difference in the relative micromotion (p = 0.791 and 0.380, respectively) and subsidence (p = 0.301 and 0.176, respectively) of the component between the two groups at both angles of flexion. Both designs of component offered good strength of fixation in this cadaver study.

The effect of bone lavage on femoral cement penetration and interface temperature during Oxford unicompartmental knee arthroplasty with cement.

BACKGROUND: Aseptic loosening is the most common cause for revision unicompartmental knee arthroplasty and is associated with failure of the bone-cement or cement-implant interface. The purpose of the present study was to analyze different bone lavage techniques for the bone-cement and cement-implant interfaces of the femoral component and to study the effect of these techniques on cement penetration and on interface temperature. METHODS: In an experimental cadaver study, Oxford unicompartmental knee arthroplasty was performed in twenty-four matched-paired knees to study the effect of pulsed lavage compared with syringe lavage on femoral cement penetration and interface temperature. Interface temperature, cement penetration pressure, and ligament tension forces were measured continuously during the procedure, and cement penetration was determined by performing sagittal bone cuts. RESULTS: Cleansing the femoral bone stock with use of pulsed lavage (Group B) led to increased femoral cement penetration (mean, 1428 mm²; 95% confidence interval, 1348 to 1508 mm²) compared with syringe lavage (Group A) (mean, 1128 mm²; 95% confidence interval, 1038 to 1219 mm²) (p < 0.001). Interface temperature was higher in Group B (mean 22.6°C; 95% confidence interval, 20.5°C to 24.1°C) than in Group A (mean, 21.0°C; 95% confidence interval, 19.4°C to 23.0°C) (p = 0.028), but temperatures never reached critical values for thermal damage to the bone. CONCLUSIONS: Pulsed lavage leads to an increased femoral cement penetration without the risk of heat necrosis at the bone-cement interface.

Multiple Acetabular Revisions in THA - Poor Outcome Despite Maximum Effort.

A consecutive series of 52 acetabular revisions was evaluated retrospectively. Inclusion criteria for all patients were at least one former exchange of the acetabular component. Reconstruction was performed with reliable techniques and implants other than extensively porous coated device (e.g. tantalum). The mean follow up was 5.63 (0.01-14.05) years. Cumulative survival at 14.05 years with removal of the acetabular component due to aseptic loosening or the worst case criterion (removal of the acetabular component for any cause and/or lost to follow-up) as the end point was 66.38 (95 % C.-I.: 47.80-84.96) % and 58.42 (95 % C.-I.: 41.01-75.83) %, respectively. The cumulative survival rate with mechanical failure of the acetabular reconstruction as the endpoint was significantly lower in patients with two or more previous revisions in comparison to those with only one former procedure (log rank test: p=0,0112 respectively). The mean Merle d'Aubignée-score improved from 7.3 (0-14) preoperatively to 10.6 (0-17) points at latest follow up examination.Survival of acetabular reconstructions with common techniques and implants is decreasing with the number of previous revisions. This may cause major concerns with regard to the rising number of patients needing repeated revisions. Maximizing durability of primary THA, precise preoperative planning as well as improved techniques and implants for revision may decrease this problem in the long term.

[Results of 5 to 10-year follow-up after hip resurfacing. A systematic analysis of the literature on long-term results]. / Fünf- bis Zehn-Jahresergebnisse für den Oberflächenersatz des Hüftgelenks. Eine systematische Literaturanalyse der mittelfristigen Standzeiten.

Hip resurfacing is a common method for therapy of coxarthritis and is currently under discussion. The aim of this study was to analyze hip resurfacing follow-up studies with more than 5 years follow-up time. A total of 17 studies which matched the inclusion criteria were analyzed. The survival rate after 5-6 years was 96.3%, after 7-8 years 93.8% and after 9-10 years 90%. Young men with primary coxarthritis and surgery by an experienced surgeon showed the best results. The main causes for revision were aseptic loosening with 34.4% and fracture of the proximal femur with 31.9%. Dislocation as a cause for revision was rare and occurred in 2.8% of all cases. Hip resurfacing showed worse results than conventional hip arthroplasty. The risk for complications was high especially for women, with small prostheses and in patients with suboptimal positioning of the prosthesis.

The importance of pulsed lavage on interface temperature and ligament tension force in cemented unicompartmental knee arthroplasty.

BACKGROUND: Mechanical loosening is the most common cause of revision in unicompartmental knee arthroplasty. We determined the effect of bone lavage on tibial cement penetration and interface temperature with controlled ligament tension forces. We presumed pulsed lavage would allow increased cement penetration compared with syringe lavage. METHODS: Cemented unicompartmental knee arthroplasty was performed in 12 pairs of fresh-frozen knees. Lavage was performed using pulsed lavage on one side (A) and syringe lavage on the other (B). Cement penetration pressure, interface temperature, and ligament tension forces were continuously monitored during the operation. Screened radiographs were taken and cement penetration under the tibial plateau was measured. FINDINGS: The pulsed lavage group showed a mean cement penetration area of 187.24 (SD 36.37) mm², whereas 144.29 (SD 35.74) mm(2) was measured in the group with syringe lavage. Cement penetration pressure was 13.29 (SD 8.69) kPa in Group A and 20.21 (SD 7.78) kPa in Group B. Maximum interface temperatures of 46.99°C were observed in Group A and 45.02°C in Group B. INTERPRETATION: Our data showed pulsed lavage cleansing of the cancellous tibial bone substantially improved cement penetration compared with syringe lavage without reaching the temperature threshold for bone necrosis. We recommend the routine use of pulsed lavage to improve long-term fixation.

Femoral fixation pattern in cemented Oxford unicompartmental knee arthroplasty--an experimental cadaver study.

Femoral component loosening is a rare but serious complication in cemented Oxford unicompartmental knee arthroplasty (OUKA). In a cadaver study, OUKA was performed in 24 knees to evaluate the femoral fixation pattern. Due to the geometry of bone and implant, three different zones were identified. Complete cement mantles and good interdigitation were found in the spherical part of the implant (zone 1) and around the peg (zone 3), which implies that these are most important for implant fixation. The posterior plane facet (zone 2) is the weak point of the interface due to incompleteness of the cement mantle and a lack of interdigitation. This study suggests that the cancellous bone in zone 2 and the drill holes in sclerotic bone areas should be filled with cement and pressurised prior to component seating.

[Acetabular reinforcement rings in revision total hip arthroplasty: midterm results in 298 cases]. / Abstützschalen in der Revisionsendoprothetik der Hüfte : Mittelfristige Ergebnisse von 298 Implantaten.

BACKGROUND: Acetabular revision in total hip arthroplasty (THA), especially for loose or migrated cup components with collateral bone loss, remains a great surgical challenge. The aim should always be a functionally favorable reconstruction of the rotation center with sufficient load capacity of the acetabulum. Commonly used implants in Europe are the Mueller ring, the Ganz ring, and the Burch-Schneider cage. PATIENTS AND METHODS: We report our results of 298 patients (298 hips) with a median follow-up period of 4 (range 0-17) years in a retrospective series. RESULTS: Follow-up data were available in 224 cases (75%). A radiographic examination was performed in 176 (59%) patients. Another 54 patients (18%) had died in the follow-up period, while another three patients (1%) were lost to follow-up. Eighteen patients (16%) underwent re-revision, in nine cases for aseptic loosening and in the remaining nine cases for infection. In seven additional cases (2%), radiological and clinical failure was found during follow-up. The overall survival rate was 94% at 5 years and 89% at 8 years. CONCLUSION: Revision THA using acetabular reinforcement rings results in acceptable midterm results. However, septic complications and lysis of the bone graft with consecutive failure of the reinforcement ring remain problematic.

[Cementing techniques for hip resurfacing arthroplasty. What do we know?]. / Die femorale Zementiertechnik für den Oberflächenersatz des Hüftgelenks. Was wissen wir eigentlich?

In recent retrieval studies, overpenetration of cement, incomplete seating of the prosthesis with a resulting polar cement mass, or both have been associated with failure of current-generation femoral resurfacing arthroplasties. Cementing technique was found to strongly influence cement pressure, interface temperature, and cement penetration in the few cementing studies published on hip resurfacing arthroplasty. Component-filling cementing techniques resulted in a risk of incomplete seating, variable degrees of overpenetration of the interior area, and a lack of cement at the outer lower edges of the bone under the resurfacing components. This caused exposure to high temperatures, which can cause bone necrosis. The manual technique with high-viscosity cement showed advantages in our experimental work. It was possible to achieve high cement contents in the outer fixation area without the negative effects of interior area penetration.

The indication for gamma probe-guided surgery of spinal osteoid osteomas.

The standard treatment for osteoid osteomas is CT-guided radiofrequency ablation (RFA). This minimally invasive procedure is effective in terms of pain reduction as well as the recurrence rate. Nevertheless, the use for spinal lesions is limited due to a possible thermal damage of neural structures. Although the literature is contradictory, RFA should only be used when a cortical shell between the lesion and the spinal canal is existent. We present seven cases (five males, two females, mean age 23 years) with spinal osteoid osteoma in which RFA was not applicable and open resection with the use of probe-guided surgery (PGS) was performed. The principle of PGS is that after preoperative bone scintigraphy, a handheld radiation probe is used intraoperatively for tumour localisation. Here, exposure and bone resection can be minimised and completeness of tumour excision may be estimated. At the initial measurement we found a hot-spot (maximum count-rate) in all patients and after tumour resection, the signal decreased by a mean of 68% in the operative field. After a mean follow-up of 17 months one patient had residual pain but no patient had signs of tumour recurrence. The authors recommend to use PGS for those spinal osteoid osteomas where RFA is not applicable and intraoperative localisation--and here complete resection--of the tumour is difficult.

[The cemented MS-30 stem. A multi-surgeon series of 333 consecutive cases]. / Der zementierte MS-30-Schaft : Ergebnisse einer Multi-surgeon-Serie von 333 konsekutiven Fällen.

INTRODUCTION: So far there is only one peer-reviewed long-term publication from the inventors' clinic for the MS-30 stem. MATERIAL AND METHODS: In a retrospective study we followed the first 333 consecutive MS-30 stems. All patients with 5- to 11-year follow-up were clinically and radiographically evaluated. At the time of implantation the criteria of modern cementing techniques were not implemented. Clinical evaluation was done using the scores of Harris and Merle d'Aubigné and Postel. Radiographic evaluation included quality of the cement mantle (true lateral radiographs taken under fluoroscopy), stem subsidence, loosening signs, and the risk for pending failure. RESULTS: At follow-up 12 hips had undergone femoral revision: 3 for aseptic loosening, 6 for infection, 1 for periprosthetic fracture, and 2 for recurrent dislocation. The overall survival for all reasons at 10 years was 96.1%; survival with aseptic loosening as an end point was 99.0%. The median Harris Hip Score at follow-up was 80 (26-100) points. Radiological evaluation revealed a thin cement mantle (<2 mm) in approximately 2/3, predominantly on the lateral views (Gruen zones 8/9). One-third of all reviewed prostheses were considered at risk for pending failure, which strongly correlated with the initial quality of the cement mantle. CONCLUSION: Midterm results with the MS-30 stem are encouraging and an even better long-term outcome can be expected with a better cement technique.

[Long-term results of interventional treatment of large unresectable hepatocellular carcinoma (HCC): significant survival benefit from combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) compared to TACE monotherapy]. / Langzeitergebnisse der interventionellen Therapie von grossen, inoperablen hepatozellulären Karzinomen (HCC): signifikanter Uberlebensvorteil von transarterieller Chemoembolisation (TACE) und perkutaner Ethanolinjektion (PEI) gegenüber der TACE-Monotherapie.

PURPOSE: A retrospective analysis of long-term efficacy of combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) and TACE monotherapy was conducted in patients with large, non-resectable hepatocellular carcinoma (HCC). METHODS AND MATERIALS: Fifty patients with large, unresectable HCC lesions underwent selective TACE. Liver cirrhosis was present in 42 patients, due to alcohol abuse (n = 22) and viral infection (n = 17). In three patients, the underlying cause for liver cirrhosis remained unclear. Child A cirrhosis was found in 22 and Child B cirrhosis in 20 patients. Repeated and combined TACE and PEI were performed in 22 patients and repeated TACE monotherapy was performed in 28 patients. Survival and complication rates were determined and compared. RESULTS: The 6-,12-, 24- and 36-month survival rates were 61 %, 21 %, 4 %, and 4 % for TACE monotherapy and 77 %, 55 %, 39 % and 22 % for combined TACE and PEI (Kaplan-Meier method). The kind of treatment significantly affected the survival rate (p = 0.002 log-rank test). Severe side effects were present in two patients of the monotherapy group and in three patients of the combination therapy group. CONCLUSION: The combination of TACE and PEI is an effective and safe method in the palliative treatment of large HCC that has the potential of improving long term survival compared to TACE monotherapy.