Feasibility of single-use 3D-printed instruments for total knee arthroplasty

2019 ◽  
Vol 101-B (7_Supple_C) ◽  
pp. 115-120 ◽  
Author(s):  
J. Hooper ◽  
R. Schwarzkopf ◽  
E. Fernandez ◽  
A. Buckland ◽  
J. Werner ◽  
...  

Aims This aim of this study was to assess the feasibility of designing and introducing generic 3D-printed instrumentation for routine use in total knee arthroplasty. Materials and Methods Instruments were designed to take advantage of 3D-printing technology, particularly ensuring that all parts were pre-assembled, to theoretically reduce the time and skill required during surgery. Concerning functionality, ranges of resection angle and distance were restricted within a safe zone, while accommodating either mechanical or anatomical alignment goals. To identify the most suitable biocompatible materials, typical instrument shapes and mating parts, such as dovetails and screws, were designed and produced. Results Before and after steam sterilization, dimensional analysis showed that acrylonitrile butadiene styrene could not withstand the temperatures without dimensional changes. Oscillating saw tests with slotted cutting blocks produced debris, fractures, or further dimensional changes in the shape of Nylon-12 and polymethylmethacrylate (MED610), but polyetherimide ULTEM 1010 was least affected. Conclusion The study showed that 3D-printed instrumentation was technically feasible and had some advantages. However, other factors, such as whether all procedural steps can be accomplished with a set of 3D-printed instruments, the logistics of delivery, and the economic aspects, require further study. Cite this article: Bone Joint J 2019;101-B(7 Supple C):115–120

2021 ◽  
Vol 29 (1) ◽  
pp. 230949902110020
Author(s):  
Seikai Toyooka ◽  
Hironari Masuda ◽  
Nobuhiro Nishihara ◽  
Takashi Kobayashi ◽  
Wataru Miyamoto ◽  
...  

Purpose: To evaluate the integrity of lateral soft tissue in varus osteoarthritis knee by comparing the mechanical axis under varus stress during navigation-assisted total knee arthroplasty before and after compensating for a bone defect with the implant. Methods: Sixty-six knees that underwent total knee arthroplasty were investigated. The mechanical axis of the operated knee was evaluated under manual varus stress immediately after knee exposure and after navigation-assisted implantation. The correlation between each value of the mechanical axis and degree of preoperative varus deformity was compared by regression analysis. Results: The maximum mechanical axis under varus stress immediately after knee exposure increased in proportion to the degree of preoperative varus deformity. Moreover, the maximum mechanical axis under varus stress after implantation increased in proportion to the degree of preoperative varus deformity. Therefore, the severity of varus knee deformity leads to a progressive laxity of the lateral soft tissue. However, regression coefficients after implantation were much smaller than those measured immediately after knee exposure (0.99 vs 0.20). Based on the results of the regression formula, the postoperative laxity of the lateral soft tissue was negligible, provided that an appropriate thickness of the implant was compensated for the bone and cartilage defect in the medial compartment without changing the joint line. Conclusion: The severity of varus knee deformity leads to a progressive laxity of the lateral soft tissue. However, even if the degree of preoperative varus deformity is severe, most cases may not require additional procedures to address the residual lateral laxity.


2015 ◽  
Vol 2015 ◽  
pp. 1-3 ◽  
Author(s):  
Dongquan Shi ◽  
Xingquan Xu ◽  
Anyun Guo ◽  
Jin Dai ◽  
Zhihong Xu ◽  
...  

Introduction. Mechanical alignment deviation after total knee arthroplasty is a major reason for early loosening of the prosthesis. Achieving optimum cement penetration during fixation of the femoral and tibial component is an essential step in performing a successful total knee arthroplasty. Bone cement is used to solidify the bone and prosthesis. Thickness imbalance of bone cement leads to the deviation of mechanical alignment. To estimate the influence of bone cement, a retrospective study was conducted.Materials and Methods. A total of 36 subjects were studied. All the TKA were performed following the standard surgical protocol for navigated surgery by medial approach with general anaesthesia. Prostheses were fixed by bone cement.Results. We compared the mechanical axis, flexion/extension, and gap balance before and after cementation. All the factors were different compared with those before and after cementation. Internal rotation was reached with statistical significance (P=0.03).Conclusion. Bone cement can influence the mechanical axis, flexion/extension, and gap balance. It also can prompt us to make a change when poor knee kinematics were detected before cementation.


2012 ◽  
Vol 45 (13) ◽  
pp. 2215-2221 ◽  
Author(s):  
K.C.T. Ho ◽  
S.K. Saevarsson ◽  
H. Ramm ◽  
R. Lieck ◽  
S. Zachow ◽  
...  

2014 ◽  
Vol 29 (7) ◽  
pp. 1388-1393 ◽  
Author(s):  
David A.J. Wilson ◽  
Janie L. Astephen Wilson ◽  
Glen Richardson ◽  
Michael J. Dunbar

2010 ◽  
Vol 25 (6) ◽  
pp. 964-969 ◽  
Author(s):  
Atsushi Kitagawa ◽  
Nobuhiro Tsumura ◽  
Takaaki Chin ◽  
Kazuyoshi Gamada ◽  
Scott A. Banks ◽  
...  

Author(s):  
Sara Birch ◽  
Torben Bæk Hansen ◽  
Maiken Stilling ◽  
Inger Mechlenburg

Background: Pain catastrophizing is associated with pain both before and after a total knee arthroplasty (TKA). However, it remains uncertain whether pain catastrophizing affects physical activity (PA). The aim was to examine the influence of pain catastrophizing on the PA profile, knee function, and muscle mass before and after a TKA. Methods: The authors included 58 patients with knee osteoarthritis scheduled for TKA. Twenty-nine patients had a score >22 on the Pain Catastrophizing Scale (PCS), and 29 patients had a score <11. PA was measured with a triaxial accelerometer preoperative, 3 months, and 12 months after TKA. Other outcome measures consisted of the Knee Osteoarthritis Outcome Score and dual-energy X-ray absorptiometry scans. Results: The authors found no difference in PA between patients with a better/low or a worse/high score on the PCS, and none of the groups increased their mean number of steps/day from preoperative to 12 months postoperative. Patients with better/low PCS scores had higher/better preoperative scores on the Knee Osteoarthritis Outcome Score subscales (symptoms, pain, and activity of daily living), and they walked longer in the 6-min walk test. Further, they had lower body mass index, lower percent fat mass, and higher percent muscle mass than patients with worse/high PCS scores both before and after a TKA. Conclusion: Preoperative pain catastrophizing did not influence PA before or after a TKA. Although the patients improved substantially in self-reported knee function, their PA did not increase. This may be important to consider when the clinicians are informing the patients about the expected benefits from the operation.


2020 ◽  
Vol 102-B (10) ◽  
pp. 1324-1330
Author(s):  
Stijn Herregodts ◽  
Mathijs Verhaeghe ◽  
Rico Paridaens ◽  
Jan Herregodts ◽  
Hannes Vermue ◽  
...  

Aims Inadvertent soft tissue damage caused by the oscillating saw during total knee arthroplasty (TKA) occurs when the sawblade passes beyond the bony boundaries into the soft tissue. The primary objective of this study is to assess the risk of inadvertent soft tissue damage during jig-based TKA by evaluating the excursion of the oscillating saw past the bony boundaries. The second objective is the investigation of the relation between this excursion and the surgeon’s experience level. Methods A conventional jig-based TKA procedure with medial parapatellar approach was performed on 12 cadaveric knees by three experienced surgeons and three residents. During the proximal tibial resection, the motion of the oscillating saw with respect to the tibia was recorded. The distance of the outer point of this cutting portion to the edge of the bone was defined as the excursion of the oscillating saw. The excursion of the sawblade was evaluated in six zones containing the following structures: medial collateral ligament (MCL), posteromedial corner (PMC), iliotibial band (ITB), lateral collateral ligament (LCL), popliteus tendon (PopT), and neurovascular bundle (NVB). Results The mean 75th percentile value of the excursion of all cases was mean 2.8 mm (SD 2.9) for the MCL zone, mean 4.8 mm (SD 5.9) for the PMC zone, mean 3.4 mm (SD 2.0) for the ITB zone, mean 6.3 mm (SD 4.8) for the LCL zone, mean 4.9 mm (SD 5.7) for the PopT zone, and mean 6.1 mm (SD 3.9) for the NVB zone. Experienced surgeons had a significantly lower excursion than residents. Conclusion This study showed that the oscillating saw significantly passes the edge of the bone during the tibial resection in TKA, even in experienced hands. While reported neurovascular complications in TKA are rare, direct injury to the capsule and stabilizing structures around the knee is a consequence of the use of a hand-held oscillating saw when making the tibial cut. Cite this article: Bone Joint J 2020;102-B(10):1324–1330.


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