Computer-aided planning with exact implementation into surgical technique in TKA is as accurate as intraoperative navigation

An overview on the treatment strategies of non-displaced femoral neck fracture in the elderly

Background

This paper aimed to review the databases on non-displaced femoral neck fractures in elderly patients. We also discussed the surgical and non-surgical treatments and selection of implants.

Methods

Reviewed was the literature on non-displaced femoral neck fractures in elderly patients. Four major medical databases and a combination of the search terms of “femoral neck fractures”, “nondisplaced”, “undisplaced”, “non-displaced”, “un-displaced”, “aged”, “the elderly”, and “geriatric” were used to search the literature relevant to the topic of the review.

Results

Patients who were unable to tolerate the operation and anesthesia could be treated conservatively. Otherwise, surgical treatment was a better choice. Specific surgical strategies and implant selection were important for the patient’s functional recovery.

Conclusions

The non-displaced femoral neck fractures are relatively stable but carry a risk of secondary displacement. Surgical treatments may be a better option because the implants provide additional stability and allow early exercise and ambulation. Hemiarthroplasty is also an alternative for old patients with higher risks of displacement and avascular necrosis of the femoral head.

A review of computer-assisted orthopaedic surgery systems

BACKGROUND

Computer-assisted orthopaedic surgery systems have great potential, but no review has focused on computer-assisted surgery systems for the spine, hip, and knee.

METHODS

A systematic search was performed in Web of Science and PubMed. We searched the literature on computer-assisted orthopaedic surgery systems from 2008 to the present and focused on three aspects of systems: training, planning, and intraoperative navigation.

RESULTS AND DISCUSSION

In this review study, we reviewed 34 surgical training systems, 31 surgical planning systems, and 41 surgical navigation systems. The functions and characteristics of the surgical systems were compared and analysed, and the current concerns about and the impact of the surgical systems on doctors and surgery were clarified.

CONCLUSION

Computer-assisted orthopaedic surgery systems are still in the development stage. Future surgical training systems should include synthetic models with patient anatomy. Surgical planning systems with automatic planning should be developed, and surgical navigation systems with multimodal fusion, robotic assistance and imaging should be developed.

Accuracy of a Novel 3D-Printed Patient-Specific Intramedullary Guide to Control Femoral Component Rotation in Total Knee Arthroplasty

Objective

Total knee arthroplasty (TKA) is one of the most universal and effective means for treating terminal stage osteoarthritis (OA) of knee. Accurate intramedullary guide of femur is the basis for the distal femoral cuts. Determining the surgical transepicondylar axis (sTEA) is the key to reconstruction of the femoral rotational alignment, because the correct rotational alignment can place the femoral component in the right position, balance the flexion gap so that the inner and outer tension is equal, get stability during the flexion process of the knee, and enhance the quality of life of patients. With the development of three‐dimensional printing (3DP) technology in the medical domain, the application of patient‐specific instrumentation (PSI) in arthroplasty has become more common. The aim of this study was to evaluate the accuracy of a novel 3D‐printed patient‐specific intramedullary guide to control femoral component rotation in TKA.

Methods

Eighty patients (65 females and 15 males) with knee OA were included in this prospective randomized study. The patients were divided into two groups by random number table method, 40 in each group. TKA assisted by PSI (PSI group) and conventional TKA (conventional group) was performed respectively. Clinical outcomes [operation time, postoperative drainage volume, duration of drainage, Hospital for Special Surgery knee score (HSS), American Knee Society knee score (AKS)] and radiological outcomes [hip‐knee‐ankle angle (HKA), posterior condylar angle (PCA), patella transverse axis‐femoral transepicondylar axis angle (PFA), depth of intramedullary guide] were compared between and within the two groups.

Results

PSI group had less postoperative drainage volume but longer operation time than the conventional group (P < 0.05). The AKS and HSS scores after surgery were improved compared with those before surgery in each group (P < 0.05). However, there was no significant difference in the duration of drainage and range of motion (ROM) after surgery between the two groups. For the radiological results, the HKA and PFA were improved after surgery in both groups (P < 0.05).The postoperative PFA and PCA of the PSI group were closer to 0°, which was better than that of the conventional group (P < 0.05). The depth of intramedullary guide in the PSI group was less than the conventional group (P < 0.05). But there was no significant difference in HKA before and after surgery between the two groups as well as the preoperative PFA.

Conclusion

The short‐term clinical efficacy of TKA assisted by PSI was similar to the conventional TKA. Although TKA assisted by PSI spent more time during operation, it could assist in intramedullary guide and align femoral rotation more accurately.

Pre-operative prediction of soft tissue balancing in knee arthoplasty part 1: Effect of surgical parameters during level walking

An important reason for poor functional outcome of Total Knee Arthroplasty is inadequate soft tissue balancing. Custom-made cutting guides or computer-aided surgical navigation make possible to accurately achieve what is planned; the challenge is to perform a pre-operative planning that properly accounts for soft-tissue balancing. The first step in the development of a patient-specific computer model that can predict during pre-operative planning the post-operative soft-tissue balancing is a better understanding of the role that cutting heights and angles have on the balancing of the soft tissues after TKA as the patient perform the more common daily tasks. In the present study, we conducted a sensitivity analysis of the ligament elongations during level walking due to TKA as a function of position and orientation of the cutting guides, by means of a validated patient-specific dynamic model of the post-TKA knee biomechanics. The results suggest a considerable sensitivity of the collateral ligaments elongation to the surgical variables, and in particular to the varus-valgus angles of both tibia and femur. This complete elongation map can be used as a baseline for the development of reduced-order models to be integrated in pre-operative planning environments. © 2019 The Authors Journal of Orthopaedic Research. Published by Wiley Periodicals, Inc. J Orthop Res 37:1537-1545, 2019.