Double level knee osteotomy using patient-specific cutting guides is accurate and provides satisfactory clinical results: a prospective analysis of a cohort of twenty-two continuous patients

Background. The incidence of malalignment in total knee arthroplasty(TKA) using conventional instrument has beenreported as high as 25%. A relatively new TKA system involvesthe use of a preoperative magnetic resonance image(MRI) to obtain accurate implant placement more consistently.For broad acceptance of this new technique, it iscrucial to analyze the initial intra-operative experience. Thespecific aim of this study was to evaluate the initial intra-operativeexperience of a single surgeon using this new technique. Methods. A total of 15 knees (12 patients: 6 female and 6male) were reviewed from TKA procedures using the selectedmanufacturer’s patient specific cutting guides between January2011 and April 2013 at a single institution. Patient demographicand specific parameters and intra-operative alterationsof component positioning were recorded and evaluated.Results. The preoperative plan was able to predict correctly thesize of the implanted femoral component in 87% (n = 13) andtibial component in 80% (n = 12) of the cases. However, 60% (n= 9) of cases required additional intra-operative corrections onfemoral resection, and 73% (n = 11) required an additional 2 - 4mm correction on the tibial proximal resection. Twenty percent(n = 3) required additional tibial varus/valgus correction, butthere were no tibial slope corrections for any of the 15 cases. Conclusions. The initial intra-operative experience of a singlesurgeon using current patient specific cutting guides for a selectedmanufacturer to align femoral and tibial components duringTKA has raised some concerns. We agreed with previous studiesthat caution should be taken when using patient specific cuttingguides without supportive data. The findings of this study providedadditional evidence to contest the accuracy of patient specificcutting guides with respect to the initial experience of an orthopaedicsurgeon who is trained in total joint replacement. Theresults provided more evidence to assist orthopaedic surgeonsin the decision of whether to use these patient specific systemsversus conventional TKA methods. KS J Med 2016;9(2):22-26.

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Patient-specific metal implants for focal chondral and osteochondral lesions in the knee; excellent clinical results at 2 years

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-020-06289-7 ◽

2020 ◽

Author(s):

Johannes Holz ◽

Tim Spalding ◽

Tarek Boutefnouchet ◽

Pieter Emans ◽

Karl Eriksson ◽

...

Keyword(s):

Cartilage Repair ◽

Treatment Options ◽

Clinical Results ◽

Patient Specific ◽

Osteochondral Lesions ◽

Consecutive Series ◽

Open Label ◽

Full Data ◽

Level Of Evidence ◽

Metal Implants

Abstract Purpose Surgical treatment options for the management of focal chondral and osteochondral lesions in the knee include biological solutions and focal metal implants. A treatment gap exists for patients with lesions not suitable for arthroplasty or biologic repair or who have failed prior cartilage repair surgery. This study reports on the early clinical and functional outcomes in patients undergoing treatment with an individualised mini-metal implant for an isolated focal chondral defect in the knee. Methods Open-label, multicentre, non-randomised, non-comparative retrospective observational analysis of prospectively collected clinical data in a consecutive series of 80 patients undergoing knee reconstruction with the Episealer® implant. Knee injury and Osteoarthritis Outcome Score (KOOS) and VAS scores, were recorded preoperatively and at 3 months, 1 year, and 2 years postoperatively. Results Seventy-five patients were evaluated at a minimum 24 months following implantation. Two patients had undergone revision (2.5%), 1 declined participation, and 2 had not completed the full data requirements, leaving 75 of the 80 with complete data for analysis. All 5 KOOS domain mean scores were significantly improved at 1 and 2 years (p < 0.001–0.002). Mean preoperative aggregated KOOS4 of 35 (95% CI 33.5–37.5) improved to 57 (95% CI 54.5–60.2) and 59 (95% CI 55.7–61.6) at 12 and 24 months respectively (p < 0.05). Mean VAS score improved from 63 (95% CI 56.0–68.1) preoperatively to 32 (95% CI 24.4–38.3) at 24 months. The improvement exceeded the minimal clinically important difference (MCID) and this improvement was maintained over time. Location of defect and history of previous cartilage repair did not significantly affect the outcome (p > 0.05). Conclusion The study suggests that at 2 years, Episealer® implants are safe with a low failure rate of 2.5% and result in clinically significant improvement. Individualised mini-metal implants with appropriate accurate guides for implantation appear to have a place in the management of focal femoral chondral and osteochondral defects in the knee. Level of evidence IV.

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Handheld Navigation Device and Patient-Specific Cutting Guides Result in Similar Coronal Alignment for Primary Total Knee Arthroplasty: a Retrospective Matched Cohort Study

HSS Journal ® ◽

10.1007/s11420-015-9484-2 ◽

2016 ◽

Vol 12 (3) ◽

pp. 224-234 ◽

Cited By ~ 8

Author(s):

Michael E. Steinhaus ◽

Alexander S. McLawhorn ◽

Shawn S. Richardson ◽

Patrick Maher ◽

David J. Mayman

Keyword(s):

Total Knee Arthroplasty ◽

Cohort Study ◽

Knee Arthroplasty ◽

Primary Total Knee Arthroplasty ◽

Patient Specific ◽

Matched Cohort ◽

Coronal Alignment ◽

Cutting Guides ◽

Total Knee ◽

Primary Total Knee

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Imaging, Virtual Planning, Design, and Production of Patient-Specific Implants and Clinical Validation in Craniomaxillofacial Surgery

Craniomaxillofacial Trauma & Reconstruction ◽

10.1055/s-0032-1313357 ◽

2012 ◽

Vol 5 (3) ◽

pp. 137-143 ◽

Cited By ~ 58

Author(s):

Per Dérand ◽

Lars-Erik Rännar ◽

Jan-M Hirsch

Keyword(s):

Additive Manufacturing ◽

Treatment Plan ◽

Maxillofacial Surgery ◽

Bone Substitutes ◽

Patient Specific ◽

Virtual Design ◽

Patient Specific Implants ◽

Cutting Guide ◽

Ablative Surgery ◽

Cutting Guides

The purpose of this article was to describe the workflow from imaging, via virtual design, to manufacturing of patient-specific titanium reconstruction plates, cutting guide and mesh, and its utility in connection with surgical treatment of acquired bone defects in the mandible using additive manufacturing by electron beam melting (EBM). Based on computed tomography scans, polygon skulls were created. Following that virtual treatment plans entailing free microvascular transfer of fibula flaps using patient-specific reconstruction plates, mesh, and cutting guides were designed. The design was based on the specification of a Compact UniLOCK 2.4 Large (Synthes®, Switzerland). The obtained polygon plates were bent virtually round the reconstructed mandibles. Next, the resections of the mandibles were planned virtually. A cutting guide was outlined to facilitate resection, as well as plates and titanium mesh for insertion of bone or bone substitutes. Polygon plates and meshes were converted to stereolithography format and used in the software Magics for preparation of input files for the successive step, additive manufacturing. EBM was used to manufacture the customized implants in a biocompatible titanium grade, Ti6Al4V ELI. The implants and the cutting guide were cleaned and sterilized, then transferred to the operating theater, and applied during surgery. Commercially available software programs are sufficient in order to virtually plan for production of patient-specific implants. Furthermore, EBM-produced implants are fully usable under clinical conditions in reconstruction of acquired defects in the mandible. A good compliance between the treatment plan and the fit was demonstrated during operation. Within the constraints of this article, the authors describe a workflow for production of patient-specific implants, using EBM manufacturing. Titanium cutting guides, reconstruction plates for fixation of microvascular transfer of osteomyocutaneous bone grafts, and mesh to replace resected bone that can function as a carrier for bone or bone substitutes were designed and tested during reconstructive maxillofacial surgery. A clinically fit, well within the requirements for what is needed and obtained using traditional free hand bending of commercially available devices, or even higher precision, was demonstrated in ablative surgery in four patients.

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