Non union of long bone remains a dreadful complication. The introduction of new strategies for orthopaedic surgeons to control and modulate bone healing using growth factors such as bone morphogenetic proteins (BMP) have been shown to induce bone formation and union in long bone defects and non unions. A recombinant form of BMP (BMP-2) is FDA approved to promote fracture healing in tibial non unions. The study aim was the assessment of the safety and efficacy of a single dose of recombinant human bone morphogenetic protein-2 (INDUCTOS®) combined with bank bone on the rate of bone formation and union in long bone defects and non unions. Since October 2005, 44 patients (28 men, 16 women) with a median age of 41.81 (range: 14–78) received a single dose of BMP-2 (INDUCTOS®) in an extensive segmental long bone defects (mean score: 31.7 cc +/− 63.2; range: 5–261) in combination with bone bank graft (chips or cancellous bone blocs), without any adjunct of autologous bone or bone marrow. The series included 12 femur, 24 tibia, 5 radius/ulna, 3 humerus. All fractures were stabilised using external or internal fixation (mostly Ilizarov). All cases are available for complete follow-up. Assessment of fusion was performed using digital radiographs at postoperative time, at 10 to 15 days and 1, 2, 3 month and every month till healing. Outcomes of the defects were evaluated using the Imagika® software. Clinical stabilisation of the diaphyseal non unions, restoration of the limb length and axis, solid bone fusion were observed in all but two patients within a median time of 6.1 +/− 3.0 months (range: 2.5–15.0). We observed that BMP-2 induced bone formation across the defect; radiographs showed rapid ossification, with bone graft densification and margin’s shadings. With no need for donor sites, BMP restored the continuity and stability of critical-size defects faster than what we had observed in our former practice using large amounts of autograft combined with bank bone when necessary. We believe that this procedure provide faster healing, give more comfort and less sequel to patients.
Cross-linked PE theoretically allows the use of thinner inserts and larger diameter heads than UHMWPE. This participates in reducing the risk of dislocation. Durasul® liners have demonstrated improved wear performance over UHMWPE in laboratory testing. This may also result in lower migration and loosening rates of the implants. Our first aim was the assessment of linear wear of Durasul® inserts associated with Protasul® 36 mm CoCr prosthetic heads. We compared the results with our data on 28 mm CoCr and Biolox heads. The first hypothesis was that Durasul® inserts combined with a 36 mm CoCr head would not produce more wear than would Durasul® inserts in association with a 28 mm CoCr prosthetic head. The second hypothesis was that Durasul® inserts combined with a 36 mm head could even produce less wear than a UHMWPE liner in association with a Biolox® 28 mm prosthetic head. The second aim was to correlate cup migration with polyethylene wear rate. 111 patients (37 men, 74 women) with a median age of 74 years (range: 54–90) received Durasul® liners in an Allofit Ti cup and Protasul® 36 mm heads. They were followed for minimum 5 years. 16 patients with a Durasul® liner received a 28 mm Protasul® head (control A) and 40 received a UHMWPE liner combined with a Biolox® 28 mm head (control B). Patient outcome was assessed with the HHS. PE wear assessment was performed using a specific analysis model created in the Imagika® software. Cup migration was evaluated using the EBRA-CUP® software. The preoperative and last follow-up HHS were 50.4+/−10.5 and 97.5+/−5.5 respectively. The bedding-in penetration of the prosthetic head were 0.054+/−0.009 mm (Durasul®, 36 mm CoCr head), 0.056+/−0.008 mm (Durasul®, 28 mm CoCr head) and 0.057+/−0.010 mm (UHMWPE, Biolox® 28 mm head). There were no significant differences between the different groups. The annual linear wear rates were 0.029+/−0.003 mm (Durasul®, 36 mm CoCr head), 0.032+/−0.014 mm (Durasul®, 28 mm CoCr head) and 0.087+/−0.056 mm (UHMWPE, Biolox® 28 mm head). There were no significant differences between Durasul® groups, but a P value of 0.00027 was observed between the study group and the control B group. We didn’t observed cup migration in our patients (0.09 mm medially and 0.13 mm cranially). Patient satisfaction was high with improvement of quality of life. Combined with the Durasul® inserts used in this series, 36 mm CoCr prosthetic heads had no unfavourable influence on the wear assessment compared with the use of 28 mm prosthetic heads. The annual linear wear rate of Durasul® liners was 37.84% of that seen with the UHMWPE liner. The absence of cup migration at last follow-up may indicate very low PE wear rates.
Radiographic evidence of migration of the femoral stem component after THA is the most important diagnostic sign of femoral implant loosening. Early detection of stem subsidence may help in deciding to perform revision surgery before severe bone destruction has occurred, at a moment when standard clinical and radiological follow-up may still be reassuring. The aim of this study was to identify the most appropriate bone and prosthetic landmarks to study subsidence and to determine the accuracy of the Imagika® method as compared to the ‘gold standard’ EBRA-FCA® software. 256 THA in 242 patients (102 men, 140 women) with a median age of 63.8 years (range: 36–85) received 4 different cementless or cemented prosthetic stem designs. They were followed for 10.6 years (range: 6–16). CLS® stems were used in 56 patients, MS-30® in 76, Elite® in 50 and Osteal® in 74. 4 specific analysis models were created in the Imagika® software in order to evaluate several possible landmarks on the proximal femur and on the stem, and to evaluate the possibility of using a correction factor to improve the comparability of successive x-rays taken under non standardised conditions. The most accurate prosthetic landmarks were the prosthesis shoulder in CLS® and MS-30® stems and the lateral aspect of the collar in Elite® and Osteal® stems. The best bone landmark was the top of the greater trochanter in all cases. For the whole series, the annual linear subsidence rates were 0.049+/−0.014 mm with EBRA-FCA® and 0.052+/−0.012 mm with Imagika® respectively (P = 9E-7). Migration values in the 4 different groups were respectively 0.06 +/− 0.01 mm/yr and 0.05 +/− 0.01 mm/yr in the CLS® group (P = 4.6E-6), 0.02 +/− 0.002 mm/yr and 0.06 +/− 0.09 mm/yr in the MS-30® group (P = 6.8E-4), 0.06 +/− 0.002 mm/yr and 0.04 +/− 0.003 mm/yr in the Elite® group (P = 4.2E-5), and 0.05 +/− 0.005 mm/yr and 0.06 +/− 0.004 mm/yr in the Osteal® group (P = 7.4E-7). The different prosthetic designs did not show significant differences concerning migration values when studied according both methods. Thanks to a correction factor, the Imagika® method uses all the radiographs when EBRA-FCA® rejects incomparable radiographs. The Imagika® method is more users friendly and provides excellent reliability thanks to an automatic edge detection device. Since no significant difference was observed between EBRA-FCA® and Imagika® methods whatever the prosthetic stem design studied, our results authorise us to apply these analysis models within the Imagika® software to all THAs to follow their radiographic evolution and to possibly predict the clinical evolution.
The New Jersey Low Contact Stress prosthesis was introduced in 1977. LCS mobile bearing prostheses have been implanted in patients in the United States since 1985. The PCL-sacrificing rotating platform design of the LCS® prosthesis was designed to minimally constrain knee kinematics while minimising bone-cement-prosthesis interface stresses and polyethylene wear. The purpose of the current study was to assess the in vivo rotating platform PE wear of the LCS-RP® and to check if the PE tray mobility is preserved over time. We investigated 120 total knee replacements in 108 patients (38 men, 70 women) treated by the LCS-RP® prosthesis for osteoarthritis or rheumatoid arthritis. Average age of the patients was 70.4 years (range: 36–81). Average follow-up was 15.3 years (range: 10–18). PE wear assessment was performed using a specific analysis model created in the Imagika® software on AP radiographs. Rotating platform mobility was assessed thanks to another analysis model. We used prosthetic landmarks (tip of the prosthetic stem, tibial tray and tantalum markers embedded into the PE) visible on lateral radiographs. Linear wear rates were 0.012+/−0.007 mm (tibial plate/ PE interface), 0.026+/−0.034 mm (PE/internal condyle interface) and 0.017+/−0.041 mm (PE/external condyle interface). There were no significant differences between wear values of both internal and external sides of the upper surface of the PE insert (P = 0.000054) and of tibial plate PE/external condyle PE interfaces (P = 0.0012), but a P value of 0.063 was observed between the tibial plate PE interface and the internal condyle PE interface. The PE range of motion was 5.3 +/− 1.2° (range: −2.5 (external) to +3.2 (internal)) at last follow-up as compared to the first radiograph (3 months after operation). All trays preserved there mobility in rotation. Annual PE wear rates were extremely low as well as at the lower and the upper surfaces of the mobile bearing. Our results suggest that the long term mobility conservation contributed to low PE wear rates despite a high anatomic congruency due to the prosthetic design.
