Patient - implant dimension mismatch in total knee arthroplasty: Is it worth worrying? An Indian scenario

BACKGROUND

The correct sizing of the components in both anteroposterior and mediolateral (ML) dimensions is crucial for the success of a total knee arthroplasty (TKA). The size of the implants selected is based on the intraoperative measurements. The currently used TKA implants available to us are based on morphometric measurements obtained from a Western/Caucasian population. Hence, the risk of component ML mismatch is more common in Asian sub-population, as they are of a smaller built and stature. This study aims to look into the following aspects agnitude of the ML mismatch between the femoral component and the patient's anatomical dimension, evaluation of gender variations in distal femur dimensions, and gender-wise and implant-wise correlation of ML mismatch.

MATERIALS AND METHODS

Intraoperatively, the distal femoral dimensions were measured using sterile calipers after removing the osteophytes and compared with the ML dimension of the implant used. ML mismatch length thus obtained is correlated with the various parameters.

RESULTS

Males showed larger distal femoral dimensions when compared to females. Males had larger ML mismatch. None of the implants used perfectly matched the patient's anatomical dimensions. Patients with larger mismatch had lower scorings at 2 years postoperative followup.

CONCLUSION

Implant manufacturers need to design more options of femoral implants for a better fit in our subset of patients. The exact magnitude of mismatch which can cause functional implications need to be made out. The mismatch being one of the important factors for the success of the surgery, we should focus more on this aspect.

Locked META intramedullary nailing fixation for tibial fractures via a suprapatellar approach

BACKGROUND

Intramedullary nailing is an effective approach for treatment of diaphyseal tibial fractures. However, infrapatellar intramedullary nailing can easily cause angulation and rotation displacement at the fracture ends and increase risk of postoperative infection. Intramedullary nailing via the suprapatellar approach was proved with good reduction and fixation. We used locked intramedullary nailing for the treatment of tibial fractures via a suprapatellar approach in this study.

MATERIALS AND METHODS

23 patients undergoing tibial fractures fixation by locked META intramedullary nailing via a suprapatellar approach were enrolled between June 2012 and October 2013. There were 18 males and 5 females. The average age was 35.5 years (range 18-60 years). The intraoperative data including operative time and blood loss and postoperative data consisting of hospital stays, fluoroscopy time, fracture healing time and complications were all recorded.

RESULTS

The average operative time, blood loss, fluoroscopy time and hospital stay were 78.2 ± 9.1 min, 90.4 ± 23.4 mL, 38.5 ± 6.5 s and 11 ± 3.4 days respectively. The mean followup period in all the patients was 15.5 months. Callus appeared in the patients at average 8 weeks after surgery. The mean knee and ankle range of motion were significantly improved at the last followup (P < 0.05). The average Hospital for Special Surgery and Olerud-Molander scores was 92 ± 4.3 points and 93.6 ± 3.9 points, respectively. No complications were observed.

CONCLUSION

Locked META intramedullary nail fixation via a suprapatellar approach is safe and effective for patients suffering from tibial fractures and earlier functional recovery.

A comparative study of pedicle screw fixation in dorsolumbar spine by freehand versus image-assisted technique: A cadaveric study

BACKGROUND

New and expensive technology such as three-dimensional computer assisted surgery is being used for pedicle screw fixation in dorsolumbar spine. Their availability, expenses and amount of radiation exposure are issues in a developing country. On the contrary, freehand technique of pedicle screw placement utilizes anatomic landmarks and tactile palpation without fluoroscopy or navigation to place pedicle screws. The purpose of this study was to analyze and compare the accuracy of freehand and image-assisted technique to place pedicle screws in the dorsolumbar spine of cadavers by an experienced surgeon and a resident. Evaluation was done using dissection of pedicle and computed tomography (CT) imaging.

MATERIALS AND METHODS

Ten cadaveric dorsolumbar spines were exposed by a posterior approach. Titanium pedicle screws were inserted from D5 to L5 vertebrae by freehand and image-assisted technique on either side by an experienced surgeon and a resident. CT was obtained. A blinded radiologist reviewed the imaging. The spines were then dissected to do a macroscopic examination. Screws, having evidence of cortical perforation of more than 2 mm on CT, were considered to be a significant breach.

RESULTS

A total of 260 pedicle screws were placed. The surgeon and the resident placed 130 screws each. Out of 130 screws, both of them placed 65 screws each by freehand and image- assisted technique each. The resident had a rate of 7.69% significant medial and 10.76% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 9.23% significant lateral breach. The expert surgeon had a rate of 6.15% significant medial and 1.53% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 6.15% significant lateral breach on CT evaluation.

CONCLUSION

Freehand technique is as good as the image-assisted technique. Under appropriate supervision, residents can safely learn to place freehand pedicle screws with an acceptable violation rate.

Evaluation of the sterilization efficacy of domestic electric drills used in orthopaedic surgeries

It is estimated that electric drills (ED) have been used in orthopaedic surgeries for bone drilling for more than 50 years in Brazilian hospitals. It is an electric, thermosensitive equipment, not indicated for surgical use, which has not been previously evaluated regarding the sterilization efficacy, being suspect of infection risk. This study evaluated the efficacy of sterilization by ethylene oxide (EtO) of new drills that were intentionally contaminated with Bacillus atrophaeus spores. An experimental, laboratory, randomized applied research was developed, where 16 electric drills were analyzed, in addition to positive and negative controls. All the previously cleaned and sterilized equipment were submitted to contamination by spores. The experimental group was submitted to cleaning and sterilization by EtO and test of sterility by filtration through a 0.45 >m membrane. The membranes were cultivated and Gram and Wirtz-Conklin staining were carried out in positive results for spore visualization. An efficacy of 99.99999881% of the process of sterilization by EtO was confirmed, with a probability of survival of 1.19 x 10 ^-8. Under the development conditions of the experiment, the efficacy of the sterilization of ED by EtO was confirmed.