Abstract:In a pig bone model mimicking the human trapezium, we assessed the cementless fixation of trapezial cups in cancellous and cortical bone. Thirty-two saddle-shaped pig forefoot bones were prepared for cup fixation. Conical Konos cups (Beznoska, Kladno, Czech Republic) size 9 mm or 10 mm diameter were impacted. Cup migration was evaluated with repeated radiostereometry after intervals of cyclic-load tests. Migration increased for every load-interval up to 750 N and was higher with cancellous bone fixation than w… Show more
“…Furthermore, for a larger cup diameter, the surface area of the Moovis cups has a greater percentage increase compared to the Type T cup. An experimental study of the conical Konos cup (Beznoska, Kladno, Czech Republic) inserted with cortical bone rim fixation showed that the risk difference for failure was 63% in favor of 10 mm cups compared to 9 mm cups [28].…”
Section: Discussionmentioning
confidence: 99%
“…For conical cups, the surface area and cup diameter have been shown to affect the primary mechanical stability and load tolerance after press-fit fixation in bone [28]. Considering the same cup diameter of conical cups and hemispherical cups, the surface area is smaller for hemispherical cups [28]. Therefore, the postoperative load tolerance until achievement of secondary osseointegration is likely higher for conical cups.…”
Section: Introductionmentioning
confidence: 99%
“…Radiostereometry (RSA) is a precise imaging method for the measurement of implant migration, and early implant migration has a high predictive value for longer‐term fixation of hip and knee arthroplasty [18, 22, 23, 33]. RSA is a validated method for evaluation of cup fixation in TMC arthroplasty [15], which has been used for evaluation of prospective cup migration in clinical studies [16, 27] as well as for evaluation of primary mechanical cup fixation in an experimental pig bone model [14, 28].…”
Purpose
The most used cup designs for trapeziometacarpal (TMC) arthroplasty are of hemispherical and conical geometrical shape. Using a validated pig bone model, we compared the bone fixation using radiostereometry (RSA).
Methods
Twenty saddle-shaped pig forefoot bones were prepared with insertion of bone markers and reaming. Hemispherical Type T cups (Beznoska, Kladno, Czech Republic) (N = 10) and conical Moovis cups (Stryker, Pusignan, France) (N = 10) of 9-mm diameter were inserted press-fit. The bones were fixed in cement blocks for stability, and the cups were loaded in a motorized test stand. First, a low-pressure cyclic load test (0—150N) with 130 compression cycles was performed. Next, a push-in test of progressive loads with 50N increments (range: 150–900N) was applied until a visual change in cup position appeared. Cup migration was evaluated with RSA after every new load application. Cup failure was defined as total translation > 0.5 mm between two load applications.
Results
Both cup types tolerated a compression load of 450 N without failure. Beyond this load level, the total translation cup migration of mean 0.20 mm (95% CI 0.11; 0.30) for the Type T group was higher than mean 0.10 mm (95% CI 0.06; 0.15) of the Moovis group (p = 0.046). The Hazard ratio for failure was 0.52 (95% CI 0.12; 2.17) (p = 0.37), indicating that the risk of failure was two-fold higher in the Type T group.
Conclusion
We conclude that conical TMC cups have superior fixation as compared to hemispherical cups above a loading level of 450 N, which correspond to a 3.8 kg tip-pinch.
In a clinical perspective, based on the fixation strength of both cup types, it seems safe to allow light-load activities of daily living such as buttoning a shirt and using a key shortly after surgery and until sufficient osseointegration is achieved.
“…Furthermore, for a larger cup diameter, the surface area of the Moovis cups has a greater percentage increase compared to the Type T cup. An experimental study of the conical Konos cup (Beznoska, Kladno, Czech Republic) inserted with cortical bone rim fixation showed that the risk difference for failure was 63% in favor of 10 mm cups compared to 9 mm cups [28].…”
Section: Discussionmentioning
confidence: 99%
“…For conical cups, the surface area and cup diameter have been shown to affect the primary mechanical stability and load tolerance after press-fit fixation in bone [28]. Considering the same cup diameter of conical cups and hemispherical cups, the surface area is smaller for hemispherical cups [28]. Therefore, the postoperative load tolerance until achievement of secondary osseointegration is likely higher for conical cups.…”
Section: Introductionmentioning
confidence: 99%
“…Radiostereometry (RSA) is a precise imaging method for the measurement of implant migration, and early implant migration has a high predictive value for longer‐term fixation of hip and knee arthroplasty [18, 22, 23, 33]. RSA is a validated method for evaluation of cup fixation in TMC arthroplasty [15], which has been used for evaluation of prospective cup migration in clinical studies [16, 27] as well as for evaluation of primary mechanical cup fixation in an experimental pig bone model [14, 28].…”
Purpose
The most used cup designs for trapeziometacarpal (TMC) arthroplasty are of hemispherical and conical geometrical shape. Using a validated pig bone model, we compared the bone fixation using radiostereometry (RSA).
Methods
Twenty saddle-shaped pig forefoot bones were prepared with insertion of bone markers and reaming. Hemispherical Type T cups (Beznoska, Kladno, Czech Republic) (N = 10) and conical Moovis cups (Stryker, Pusignan, France) (N = 10) of 9-mm diameter were inserted press-fit. The bones were fixed in cement blocks for stability, and the cups were loaded in a motorized test stand. First, a low-pressure cyclic load test (0—150N) with 130 compression cycles was performed. Next, a push-in test of progressive loads with 50N increments (range: 150–900N) was applied until a visual change in cup position appeared. Cup migration was evaluated with RSA after every new load application. Cup failure was defined as total translation > 0.5 mm between two load applications.
Results
Both cup types tolerated a compression load of 450 N without failure. Beyond this load level, the total translation cup migration of mean 0.20 mm (95% CI 0.11; 0.30) for the Type T group was higher than mean 0.10 mm (95% CI 0.06; 0.15) of the Moovis group (p = 0.046). The Hazard ratio for failure was 0.52 (95% CI 0.12; 2.17) (p = 0.37), indicating that the risk of failure was two-fold higher in the Type T group.
Conclusion
We conclude that conical TMC cups have superior fixation as compared to hemispherical cups above a loading level of 450 N, which correspond to a 3.8 kg tip-pinch.
In a clinical perspective, based on the fixation strength of both cup types, it seems safe to allow light-load activities of daily living such as buttoning a shirt and using a key shortly after surgery and until sufficient osseointegration is achieved.
“…2 ). The central hard subchondral bone of the distal articular surface of the trapezium should be preserved because it improves the mechanical fixation of a cementless cup ( 37 ). Figure 2 Removal of the medial and lateral osteophytes at the distal articular surface of the trapezium.…”
Total joint replacement has certain advantages over other surgical treatment methods for osteoarthritis of the thumb carpometacarpal joint, including restoration of thumb length and alignment, good cosmetical result, fast recovery of hand function and prevention of iatrogenic complications at neighbouring joints.
Disadvantages include the technical difficulty to perform this surgery and a possible higher complication rate.
A meticulous surgical technique is mandatory.
Combined with a cementless and modular ball-in-socket implant with a metal-on-polyethylene friction couple, a 10-year survival rate higher than 90% can be expected.
Revision surgery is possible with implant exchange or conversion to trapeziectomy.
“…Fixation in cancellous bone has been shown to be worse compared with cortical bone in a recent experimental study using porcine bone. 19 Combined with a reduced contact area between the prosthesis and the surrounding bone, especially in osteoporotic bone, this may lead to suboptimal fixation of the prosthesis, potentially affecting the long-term implant survival.…”
Aims Stemless humeral implants have been developed to overcome stem-related complications in total shoulder arthroplasty (TSA). However, stemless implant designs may hypothetically result in less stable initial fixation, potentially affecting long-term survival. The aim of this study is to investigate early fixation and migration patterns of the stemless humeral component of the Simpliciti Shoulder System and to evaluate clinical outcomes. Methods In this prospective cohort study, radiostereometric analysis (RSA) radiographs were obtained in 24 patients at one day, six weeks, six months, one year, and two years postoperatively. Migration was calculated using model-based RSA. Clinical outcomes were evaluated using the visual analogue scale (VAS), the Oxford Shoulder Score (OSS), the Constant-Murley Score (CMS), and the Disabilities of the Arm, Shoulder and Hand (DASH) score. Results At two years, median translation along the x-, y-, and z-axis was -0.12 mm (interquartile range (IQR) -0.18 to 0.02), -0.17 mm (IQR -0.27 to -0.09), and 0.09 mm (IQR 0.02 to 0.31). Median rotation around the x-, y-, and z-axis was 0.12° (IQR -0.50 to 0.57), -0.98° (IQR -1.83 to 1.23), and 0.09° (IQR -0.76 to 0.30). Overall, 20 prostheses stabilized within 12 months postoperatively. Four prostheses showed continuous migration between 12 and 24 months. At two-year follow-up, with the exception of one revised prosthesis, all clinical scores improved significantly (median VAS difference at rest: -3.0 (IQR -1.5 to -6.0); OSS 22.0 (IQR 15.0 to 25.0); CMS 29.5 (IQR 15.0 to 35.75); and DASH -30.0 (IQR -20.6 to -41.67) (all p < 0.001)) with the exception of one revised prosthesis. Conclusion In conclusion, we found that 20 out of 24 implants stabilized within 12 months postoperatively. The significance of continuous migration in four implants is unclear and future research on the predictive value of early migration for future loosening in TSA is required. Clinical results revealed a clinically relevant improvement. Cite this article: Bone Joint J 2022;104-B(1):76–82.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
