Anthony Viste

Periprosthetic osteolysis after AES total ankle replacement: Conventional radiography versus CT-scan

BACKGROUND The aim of this study was to compare conventional X-rays and CT-scan in detecting peri-prosthetic osteolytic lesions, a major concern after total ankle replacement (TAR). METHODS We prospectively assessed 50 patients (mean age 56 years), consecutively operated on by the same senior surgeon, between 2003 and 2006 and with a mean follow-up period of 4 years (range, 2-6.2). The component used was AES total ankle replacement. The etiologies for total ankle arthroplasty were: posttraumatic in 50%, osteoarthritis secondary to instability in 36%. Plain radiographs were analyzed by 4 independent observers, using a 10-zone protocol (location) and 5 size categories. RESULTS At 4-year follow-up, all patients had been CT-scan assessed with the same protocol by 2 independent observers. Plain radiographs showed dramatic progression of severe periprosthetic lyses (>10mm): from 14% to 36% of interface cysts for the tibial component respectively at 2 and 4-year follow-up and from 4% to 30% for the talar implant. The talar component was more accurately assessed by CT-scan (mean frontal and sagittal talar lesion: from 270 mm2 to 288 mm2 for CT-scan versus 133 mm2 to 174 mm2 for X-rays). For tibial cysts, axial views showed larger lesions (313 mm2 than frontal (194 mm2) or sagittal (213.5 mm2) views. At 4-year follow-up, 24% of patients had revision with curetage or arthrodesis, and at 7 years follow-up 38% were revised. CONCLUSION These results are similar to recent AES series, justifying withdrawal of this device. CT-scan was more accurate than X-rays for detecting and quantifying periprosthetic osteolysis. We recommend a yearly radiological control and CT-scan in case of lesion on X-rays.

Autologous chondrocyte implantation for traumatic full-thickness cartilage defects of the knee in 14 patients: 6-year functional outcomes.

BACKGROUND Autologous chondrocyte implantation (ACI) was introduced in 1987 in Sweden by Brittberg and Peterson for the treatment of severe chondral defects of the knee. Here, our objective was to evaluate mid-term outcomes of ACI in young athletic patients with deep chondral defects of the knee after trauma. HYPOTHESIS ACI is effective in filling full-thickness chondral defects of the knee. PATIENTS AND METHODS We prospectively monitored 14 patients, with International Cartilage Repair Society grade III or IV lesions, who underwent ACI between 2001 and 2006. Standard evaluation measurements were used. Mean age at surgery was 37.7 years (range, 30-45). A history of surgery on the same knee was noted in ten (67%) patients. The defect was on the medial femoral condyle in 11 patients, lateral femoral condyle in two patients, and both femoral condyles in one patient. Mean defect surface area after debridement was 2.1cm(2) (1-6.3). RESULTS After a mean follow-up of six years, improvements were noted in 12 (86%) patients, with an International Knee Documentation Committee (IKDC) score increase from 40 (27.6-65.5) to 60.2 (35.6-89.6) (P=0.003) and a Brittberg-Perterson score decrease from 54.4 (11.8-98.2) to 32.9 (0-83.9) (P=0.02), between the preoperative assessment and last follow-up. The visual analogic scale pain score decreased from 66.3 (44-89) to 23.2 (0-77) (P=0.0006). In two (14%) patients, no improvements were detectable at last follow-up. The remaining 12 patients were satisfied and able to resume sporting activities, albeit at a less strenuous level. Two ACI-specific complications occurred, namely, periosteal hypertrophy treated with debridement in one patient and transplant delamination in another. DISCUSSION Our findings are consistent with previous reports but cover a longer follow-up period. Although the outcomes are promising, longer follow-ups are needed to confirm the long-term effectiveness of ACI. LEVEL OF EVIDENCE IV, prospective therapeutic study.

Metasul vs Cerasul bearings: a prospective, randomized study at 9 years.

The aims of our study were to compare metal-on-metal (Metasul) and ceramic-on-ceramic (Cerasul) bearings and to evaluate the clinical and radiographic results of these 2 different hard-on-hard bearings. We conducted a prospective, randomized study on a series of 250 cementless primary total hip arthroplasties. The prostheses were similar in all aspects except for the bearing surfaces: 50% of Metasul bearing and 50% of Cerasul bearing. All the patients were evaluated both clinically and radiographically. No patient was lost to follow-up. Clinical outcomes in both groups were similar. Considering aseptic loosening as the end point for failure, the 9-year survival rate was 100% for Cerasul and 98.4% for Metasul. Neither bearing outperformed the other both radiographically and clinically. The overall 9-year survival rate was 99.2% and 97.6% in the Cerasul and Metasul groups, respectively.

What are the risk factors for dislocation in primary total hip arthroplasty? A multicenter case-control study of 128 unstable and 438 stable hips ☆

INTRODUCTION Dislocation after total hip arthroplasty (THA) is a leading reason for surgical revision. The risk factors for dislocation are controversial, particularly those related to the patient and to the surgical procedure itself. The differences in opinion on the impact of these factors stem from the fact they are often evaluated using retrospective studies or in limited patient populations. This led us to carry out a prospective case-control study on a large population to determine: 1) the risk factors for dislocation after THA, 2) the features of these dislocations, and 3) the contribution of patient-related factors and surgery-related factors. HYPOTHESIS Risk factors for dislocation related to the patient and procedure can be identified using a large case-control study. PATIENTS AND METHODS A multicenter, prospective case-control study was performed between January 1 and December 31, 2013. Four patients with stable THAs were matched to each patient with a dislocated THA. This led to 566 primary THA cases being included: 128 unstable, 438 stable. The primary matching factors were sex, age, initial diagnosis, surgical approach, implantation date and type of implants (bearing size, standard or dual-mobility cup). RESULTS The patients with unstable THAs were 67±12 [37-73]years old on average; there were 61 women (48%) and 67 men (52%). Hip osteoarthritis (OA) was the main reason for the THA procedure in 71% (91/128) of the unstable group. The dislocation was posterior in 84 cases and anterior in 44 cases. The dislocation occurred within 3 months of the primary surgery in 48 cases (38%), 3 to 12 months after in 23 cases (18%), 1 to 5years after in 20 cases (16%), 5 to 10years after in 17 cases (13%) and more than 10years later in 20 cases. The dislocation recurred within 6 months of the initial dislocation in 23 of the 128 cases (18%). The risk factors for instability were a high ASA score with an odds ratio (OR) of 1.93 (95% CI: 1.4-2.6), neurological disability (cognitive, motor or psychiatric disorders) with an OR of 3.9 (95% CI: 2.15-7.1), history of spinal disease (lumbar stenosis, spinal fusion, discectomy, scoliosis and injury sequelae) with an OR of 1.89 (95% CI: 1.0-3.6), unrepaired joint capsule (all approaches) with an OR of 4.1 (95% CI: 2.3-7.37), unrepaired joint capsule (posterior approach) with an OR of 6.0 (95% CI: 2.2-15.9), and cup inclination outside Lewinneks safe zone (30°-50°) with OR of 2.4 (95% CI: 1.4-4.0). DISCUSSION This large comparative study isolated important patient-related factors for dislocation that surgeons must be aware of. We also found evidence that implanting the cup in 30° to 50° inclination has a major impact on preventing dislocation. LEVEL OF EVIDENCE Level III; case-control study.

Reproducibility of an optical measurement system for the clinical evaluation of active knee rotation in weight-bearing, healthy subjects

INTRODUCTION A knee is typically evaluated passively by a clinician during an office visit, without using dedicated measurement tools. When the knee is evaluated with the patient standing and actively participating in the movement, the results will differ than when the knee is passively moved through its range-of-motion by the surgeon. If a precise measurement system was available, it could provide additional information to the clinician during this evaluation. HYPOTHESIS The goal of this study was to verify the reproducibility of a fast, flexible optical measurement system to measure rotational knee laxity during weight-bearing. MATERIAL AND METHODS Two passive reflective targets were placed on the legs of 11 subjects to monitor femur and tibia displacements in three dimensions. Subjects performed internal and external rotation movements with the knee extended or flexed 30°. During each movement, seven variables were measured: internal rotation, external rotation and overall laxity in extension and 30° flexion, along with neutral rotation value in 30° flexion. Measurement accuracy was also assessed and the right and left knees were compared. Reproducibility was assessed over two measurements sessions. RESULTS The calculated intra-class correlation coefficient (ICC) for reproducibility was above 0.9 for five of the seven variables measured. The calculated ICC for the right/left comparison was above 0.75 for five of the seven variables measured. DISCUSSION These results confirmed that the proposed system provides reproducible measurements. Our right/left comparison results were consistent with the published literature. This system is fast, reproducible and flexible, which makes it suitable for assessing various weight-bearing movements during clinical evaluations. LEVEL OF EVIDENCE Level III, experimental study.

Innovations for the treatment of a complex bone and joint infection due to XDR Pseudomonas aeruginosa including local application of a selected cocktail of bacteriophages

found a high prevalence of ESBL producers, but no CPE. In conclusion, we report two temporally and geographically linked patients with community-onset urinary tract infection caused by the same OXA-48-producing E. coli clone. The association between OXA-48 and Cambodia in NZ suggests the Cambodian patient may have acquired the organism during recent travel and indirectly transmitted to the second patient via unknown community transmission pathways. It is possible that OXA-48-positive CPE are under-recognized in NZ due to the challenges of laboratory detection. Screening with adequate selective media for CPE is highly recommended. The forthcoming national response plan to CPE in NZ has potential to help address some of these issues.

Letter to the editor on “Dislocations after use of dual-mobility cups in cementless primary total hip arthroplasty: prospective multicentre series” by Hwang et al.

We read with great interest the study by Hwang et al. [1] regarding the incidence of dislocation in cementless primary total hip arthroplasty (THA) using a dual-mobility (DM) construct. This prospective multicentre series aimed to assess the dislocation rate at a minimum of six months’ follow-up in 165 patients with a mean age at surgery of 72 years, 69% of whom were women. The population studied was at very high risk of dislocation, including 142 femoral-neck fractures and 21 cases of osteonecrosis. The approach used was posterior in 120 hips and anterolateral in 47 cases. An M-a-MagnumTM cup (Biomet, Warsaw, IN, USA) was implanted in all cases. This is a monoblock acetabular component designed specifically for large-diameter metal-on-metal bearing. The mobile liner was a vitamin-E1-impregnated polyethylene (PE), which is the liner of the AvantageTM cup (Biomet) designed for DM use for this manufacturer. In this series, mean cup diameter was 51 mm, with a mean cup inclination of 42°. Four early dislocations occurred (2.3%) at a mean one month delay after surgery (all dislocations occurred for femoral-neck fractures using a posterior approach). Cup diameters in the dislocation group were 48, 56, 58 and 60 mm. The authors stated that: BThe dislocation rate was relatively high compared with other studies.^ Here are some comments to explain the rate was higher in this particular study.