Breakage of intramedullary femoral guide rod during total knee arthroplasty: a case report

Three-Dimensional Analysis of the Characteristics of the Femoral Canal Isthmus: An Anatomical Study

Purpose. To establish a new approach for measuring and locating the femoral intramedullary canal isthmus in 3-dimensional (3D) space. Methods. Based on the computed tomography data from 204 Chinese patients, 3D models of the whole femur and the corresponding femoral isthmus tube were reconstructed using Mimics software (Materialise, Haasrode, Belgium). The anatomical parameters of the femur and the isthmus, including the femur length and radius, and the isthmus diameter and height, were measured accordingly. Results. The mean ratio of the isthmus height versus the femoral height was 55 ± 4.8%. The mean diameter of the isthmus was 10.49 ± 1.52 mm. The femoral length, the isthmus diameter, and the isthmus tube length were significantly larger in the male group. Significant correlations were observed between the femoral length and the isthmus diameter (r = 0.24, p < 0.01) and between the femoral length and the isthmus height (r = 0.6, p < 0.01). Stepwise linear regression analyses demonstrated that the femoral length and radius were the most important factors influencing the location and dimension of the femoral canal isthmus. Conclusion. The current study developed a new approach for measuring the femoral canal and for optimization of customer-specific femoral implants.

[Reportable incidents with surgical instruments in orthopedic surgery]

BACKGROUND

Breakage of instruments in orthopedic surgery is rarely reported but the consequences can be serious for both patients and surgeons. The medical device directive classifies instruments, such as drills and saws into risk class 1 with low approval requirements. Also the number of applications of reusable instruments is not currently limited.

OBJECTIVES

The aim of this study was determine to what extent instrument failure can lead to reportable incidents and how these incidents should be processed.

METHODS

The study involved an evaluation of clinical cases from our institution with a selective literature review and discussion of the medical device directive.

RESULTS

The experience in our clinic showed that especially breakage of rasps in total hip and knee replacement surgery is associated with a major time extension of the operational procedure, a wider surgical access opening as well as complicated procedures to recover the fragments from the incident site. In individual cases a fenestration of the bone had to be conducted in order to collect the broken piece of the rasp. In one case a revision hip stem had to be used instead of the planned primary stem in order to bridge the fenestration site.

CONCLUSION

Such consequences of instrument failure were considered to be a reportable incident. A thorough documentation as well as incident reporting to the manufacturer and the Federal authorities are required for a sufficient processing and risk assessment of the incident.

Comparison of total knee arthroplasty using computer-assisted navigation versus conventional guiding systems: a prospective study

PURPOSE

To compare knee alignments in total knee arthroplasty (TKA) using computer-assisted navigation versus conventional guiding systems.

METHODS

Five men and 49 women aged 49 to 79 years underwent TKA for primary osteoarthritis of the knee with varus deformity. All valgus knees were associated with inflammatory arthritis and thus excluded. Computer-assisted navigation was used for the first 35 TKAs, whereas conventional extramedullary tibial and intramedullary femoral guiding systems were used for the next 35 TKAs. The mechanical axis, coronal tibial and femoral angles, sagittal tibial and femoral angles in the 2 groups were compared.

RESULTS

Sagittal tibial and femoral angles aligned more optimally in TKAs using computer-assisted navigation. In the respective computer-assisted navigation and conventional guiding systems, 33 (94%) and 26 (74%) of the TKAs attained a postoperative mechanical axis of <3 degrees varus/valgus.

CONCLUSION

Computer-assisted navigation gives a more consistent alignment correction and reduces outliers during implant positioning.

An intramedullary alignment guide lodging within the femoral canal during total knee arthroplasty: a case report

The usual complications of total knee arthroplasty include thrombo-embolism, infection, and loosening. We report an unusual and potentially serious complication of an intramedullary guide lodging within the femoral canal during the procedure. Considering the risk of fracture and additional exposure, the guide was not removed and was cut in situ. The rest of the operation was completed successfully and the patient made an uneventfully recovery.