[Preoperative planning and reconstruction in primary total hip arthroplasty with and without modular necks]

[Clinical trials investigating the therapeutic benefit of medical devices in orthopaedics and trauma surgery: practice examples plus commentary]

Patients recognise relevant symptoms of the two leading diseases in orthopaedics and trauma surgery: osteoarthritis and fractures. Treatment effects can be demonstrated by patient reported outcomes. Total hip arthroplasty as an example for standard treatment regimen achieves large treatment effects. It is hard to demonstrate an additional benefit against standard treatment while observing ceiling effects. Alternative instruments are needed. Navigated total knee arthroplasty is done for better control of the postoperative axis as well as to reduce the revision burden. The time interval needed to demonstrate the decrease in revision has not yet passed. Additional benefits of total knee navigation have been observed for certain patient populations and for the training of physicians. These benefits have not been investigated so far. Using registries, expert opinions and case series the desired benefit from the use of medical devices can be shown. Safety is one major aspect of innovative medical devices as an additional benefit. The safety paradigm needs intense investigation in the future. The IDEAL Statement provides the clinical researcher with the methodological framework. The METEOR Statement focused on the medical problem and the possible benefit with using innovative medical devices. Within these recommendations a broad number of study types can be employed to demonstrate the benefits for patients.

[Templating and radiological outcome monitoring for elective total hip arthroplasty. Applied quality management principles for safe patient care]

Implementation of total hip arthroplasty is a successful and reliable treatment for end-stage osteoarthritis. The biomechanics and components as well as the fixation were selected with the aid of templating. Based on a cohort of 114 patients the quality of digital X-rays and the operative results were determined. There was a slight leg lengthening and a good offset reconstruction in these patients. For the patients with replacement of the second hip the leg lengthening was smaller. The cup inclination was at 43° and 44° within the desired range. The prediction of the exact component size used was 40% for the cup and 29% for the stem.Through variation in scaling of the digital X-ray a diminishing prediction accuracy was found in our study. The correction of biomechanics and position of components showed good quality in patient care. Templating and assessment of the postoperative result in total hip arthroplasty is a model for continuous quality management and can be recommended for safe patient care.

A comparison of two implant systems in restoration of hip geometry in arthroplasty

BACKGROUND

Restoration of hip offset and leg length during THA is often limited by available implant geometries. The recent introduction of femoral components with a modular junction at the base of the neck (two modular junction components) has expanded the options to restore femoral offset and leg length.

QUESTIONS/PURPOSES

We asked (1) whether a femoral component with two modular junctions would predict by templating more frequent restoration of preoperative offset and leg length abnormalities than one with single modular junctions; and (2) how our use of these options compared with national sales data.

PATIENTS AND METHODS

We retrospectively reviewed the preoperative templating data in 100 primary THAs using single modular junction implants with only a neutral version stem and 100 THAs using two modular junction implants. We compared the frequency with which the desired leg length and offset were completely restored by preoperative templating in the two groups.

RESULTS

Offset and leg lengths were restored to within 1 mm in 85% of cases with two modular junction implants and 60% of cases with single modular junction implants. An anteverted or a retroverted neck was used in 25% of cases with the two modular junction stems. The national sales data revealed femoral neck components with version were used in 28% of cases.

CONCLUSIONS

The use of a femoral component with two modular junctions resulted in more frequent ability to restore femoral offset and leg length than a single modular junction. The advantage of clinical flexibility should be tempered by the potential concerns of prosthetic mechanical failure (which has been reported in another implant system with two modular junctions), increased third-body wear and corrosive debris, and increased prosthetic cost.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.