Purpose

Although the use of stems in revision total knee arthroplasty (RTKA) enhances survival by improving the stability of implant, questions as to the optimal fixation method as well as the vertical extent of the cement, remain unanswered. This study aimed 1) to determine the correlation between the vertical extent of cement and implant loosening; and 2) to determine the minimum cementing extent for a stable implant in revision TKA with a hybrid technique.

This study aims to implement and assess the inter and intra-reliability of a modernised radiolucency assessment system; the Radiolucency In cemented Stemmed Knee (RISK) arthroplasty classification. Furthermore, we assessed the distribution of regions affected by radiolucency in patients undergoing stemmed cemented knee arthroplasty. Stemmed knee arthroplasty cases over 7-year period at a single institution were retrospectively identified and reviewed. The RISK classification system identifies five zones in the femur and five zones in the tibia in both the anteroposterior (AP) and lateral planes. Post-operative and follow-up radiographs were scored for radiolucency by four blinded reviewers at two distinct time points four weeks apart. Reliability was assessed using the kappa statistic. A heat map was generated to demonstrate the reported regions of radiolucency. 29 cases (63 radiographs) of stemmed knee arthroplasty were examined radiographically using the RISK system. Intra-reliability (0.83) and Inter-reliability (0.80) scores were both consistent with a strong level of agreement using the kappa scoring system. Radiolucency was more commonly associated with the tibial component (76.6%) compared to the femoral component (23.3%), and the tibial anterior-posterior (AP) region 1 (medial plateau) was the most affected (14.9%). The RISK classification system is a reliable assessment tool for evaluating radiolucency around stemmed knee arthroplasty using defined zones on both AP and lateral radiographs. Zones of radiolucency identified in this study may be relevant to implant survival and corresponded well with zones of fixation, which may help inform future research

Aim. Radiologic signs such as radiolucent lines around the implant, hardware fracture or displacement and periosteal reaction have been considered suggestive of implant-associated infection. The goal of this study is to assess the correlation of these signs with confirmed internal fixation-associated infection evaluated in a prospective cohort. Method. We evaluated the radiologic appearance of preoperative standard x-ray images in 421 surgeries performed in 380 patients with internal fixation device in place (56.8% male, mean age 53 ± 17 years). This prospective study was performed in a large single center for musculoskeletal surgery from 2013–2017. Infection was suspected preoperatively in only 23.8% of the surgeries. The most common indications for surgeries in which infection was not suspected were nonunion (84 cases) and symptomatic hardware (57 cases). All removed implants were sent to sonication for biofilm removal and detection. In addition, several peri-implant tissue samples were collected. Radiographs were analyzed in a blinded fashion for signs of radiolucent lines around the implant before removal, hardware fracture or displacement, and soft periosteal reactions suggestive of infection. Diagnosis was established according to the IDSA criteria for PJI. Contingency tables were constructed to determine sensitivity and specificity, and to perform Chi-square tests to compare the presence of infection with radiological signs of infection. Results. Radiologic signs suggestive for infection were uncommon, including radiolucent lines in 48 cases (11.4%); hardware breakage in 542cases (12.4%); hardware displacement in 45 cases (10.7%); periosteal reaction in 30 cases (7.1%). Infection was confirmed in 27.6% of the surgeries, and radiological signs of infection were only marginally more common in this group. Only the presence of radiolucent lines (p = 0.47; OR = 1.86 [95% CI 1.00 – 3.38]) and periosteal reaction (p = 0.15; OR = 2.48 [1.17 – 5.26]) were significantly associated with confirmed infection. Sensitivity of radiolucent lines and periosteal reaction were low (16,4% and 12,1%, respectively), while specificity remained acceptable (90.5%and 94.8%, respectively). Conclusions. Radiologic signs of infection are uncommon, even in the context of a confirmed infection. Radiolucency surrounding the implant and the presence of a soft periosteal reaction were significantly associated with the presence of infection, though sensitivity of the signs remained very low

It is a well-known fact that total knee arthroplasty is a soft tissue operation. Soft tissue balancing is the key to success in total knee arthroplasty. It is paramount importance to preserve the maximal amount of bone on both the femur and tibial side. In Indian scenario, majority of the patients present relatively late with varus or valgus deformity. Adding to this problem is poor bone quality due to osteoporosis. Our technique of Posterior cruciate ligament (PCL) retaining TKA with tibial end plate resection facilitates soft tissue balancing, preserves PCL and maximizes bone preservation on both tibial and femoral side achieving good results in minimum seven year follow up. We retrospectively analyzed seven year outcomes of 120 knees (110 patients), mean age was 65 years (range 55 to 75 years), who received contemporary cruciate-retaining prostheses with tibial end plate resection technique. The diagnosis was osteoarthritis in 96%, Rheumatoid arthritis in 2% and posttraumatic arthritis in 2% cases. There were more number of flexible varus knees as compared to flexible valgus knees. All the patients were followed up for minimum of 84 months with average follow up of 96 months. They were followed up at 3mths, 6mths, 1,3,5,7,9 and 10 years. The functional assessment was done using knee society knee and function scores. Radiographic analysis was done to rule out subsidence and aseptic loosening. The statistical significance was assessed using chi square test. Survival analysis was done using the Kaplan Meier analysis with revision taken as the endpoint. The average ROM was 100 degrees preoperatively and 120 degrees at last follow-up. The average knee society knee score improved from 45 points preoperatively to 90 points at last follow-up. The average knee society functional score improved from 48 points preoperatively to 84 points at last follow-up (p<0.05). Radiolucency was observed in 20 knees but all except four were non-progressive lesions smaller than 2 mm. None of the implants were revised for subsidence or aseptic loosening of tibial component. The technique of PCL retaining total knee arthroplasty with tibial end plate resection in arthritic knees with flexible varus or valgus deformity yields good functional outcome in medium term follow up with relatively low incidence of subsidence of the tibial implant. This technique appears promising for total knee arthroplasty in osteoporotic bones where retaining the strong subchondral bone increases the longevity of the implant

Introduction. Acetabular fixation is one of the major factors affecting long-term longevity and durability of total hip arthroplasty (THA). Limited data exist regarding mid-term performance of modern non-cemented rim-fit cups with HA coating. The aim of this study was to assess the minimum 5 year clinical and radiographic performance of PSL cups. Therefore we retrospectively analyzed results of this component in patients that had adequate followup from a prospective institutional database. Materials and Methods. A retrospective analysis of a prospective database was performed to identify patients that underwent non-cemented THA between 2003 and 2007. 223 primary THA (210 patients) were performed by single surgeon via posterolaeral approach using a grit-blasted, HA coated rim-fit design and highly cross-linked polyethylene and were followed with minimum 5 years. The mean age was 62.5 years ± 10.8. The majority of the stems were non-cemented (87%) and the majority of the femoral heads were metal (75%), 22- or 28-mm diameter. 72% of the cups were solid and 28% were multi-hole. Clinical assessment included the Hospital for Special Surgery (HSS) hip score [18] at final follow-up, and Kaplan-Meier survivorship. All patients received pre- and post-operative anteroposterior (AP) weight bearing pelvis radiograph as well as a false profile view of the hip. Cup positioning was analyzed using the EBRA software (Einzel-Bild-Roentgen-Analysis; University of Innsbruck, Innsbruck, Austria) for functional abduction angle, anteversion, and cup migration. Osseointegration was assessed on the DeLee and Charnley's zones on both AP and false profile views. Osseointegration was defined based on the following characteristics:. presence of Stress Induced Reactive Cancellous Bone (SIRCaB), where new bone condensation (not apparent on preoperative radiographs) was present at the load bearing area of the cup (Figure 1). presence of radial trabeculae that project in continuum from the shell into the pelvis, suggesting integration of the trabecular bone onto the metal surface at the load bearing area, (Figure 2). absence of radiolucency. Radiolucency was determined by radiolucent lines that were at least 1–2 mm wide and were seen in sequential radiographs, not apparent on the initial postoperative radiograph. Linear and rotational migration was defined as > 3 mm or > 5°change in the cup position, respectively, as measured on serial radiographs. Any changes in cup position or presence of circumferential radiolucencies were considered as loosening. Results. The average duration of follow-up was 6.2 ± 1.1 years (5 – 10 years). The mean HSS score was 34.8 ± 5.0 (19 – 40). There was an overall revision rate of 3.6% (8 cases) with Kaplan-Meier survivorship for all causes of 96.4% (95% CI: 0.92 – 0.98). There was one periprosthetic femur fracture. One stem was revised for fracture at the truniun/neck junction. There were 2 dislocation (0.9%); in one hip the cup was revised and the other was treated with a constrained liner. In 3 THAs (1.3%), stems were revised for loosening/failure of osseointegration (2 non-cemented stems, 0.9%) and osteolysis (one cemented stem, 0.4%). One THA (0.45%) underwent two stage revision for treatment of periprosthetic infection. There were no revisions for cup loosening or osteolysis or ceramic head fractures. The Kaplan-Meier survivorship for cup revision for any failure was 99% (95% CI: 0.96 – 0.99) and for mechanical failure was 100% (95% CI: 0.97 – 1). In radiographic analysis, the average functional cup abduction angle and anteversion were 41.7° ± 5.2 (range, 30 – 52) and 16.8° ± 6.1 (range, 4 – 30). 96% of the cups were within the safezone of Lewinnek. There were no migration or change in cup position in any cases. Presence of SIRCaB and radial trabeculae in all 3 zones were seen in 47% and 93% of cups, respectively; both were most prevalent in Zone 1. The absence of radiolucent line was observed in 96% of cases. In 161 THAs (72%), no screws were used due to excellent initial stability. Detail radiographic osseointegration assessment in the non-screw fixation group (as compared to the THAs with screw fixation) showed significantly higher incidence of SIRCaB (49% versus 39.7%, p=0.05) and radial trabeculae (97.5% versus 94.7%, p=0.001). There was also significantly less radiolucent lines in the non-screw fixation group (p=0.001). Discussion. No evidence of radiographic failure to osseointegrate was found in this study as evidenced by absence of radiolucency, evidence of radial trabeculae, and a reactive condensation of new bone to the well-fixed acetabular shell. Interestingly, we found that the solid designs had significantly better osseointegration when compared to multi-hole designs. In this single surgeon series with mid-term follow-up reiterates that the HA-coated hemispherical rim-fit acetabular component has excellent radiographic osseointegration, clinical outcomes and high survivorship for mechanical failures