Is There an Optimal Proximal Locking Screw Length in Retrograde Intramedullary Femoral Nailing? Can We Stop Measuring for These Screws?

Determination of the safest level and screw length for the proximal locking screw in retrograde femoral nailing

OBJECTIVES

This study aims to identify the most reliable level for the proximal locking screw in retrograde femoral nails and to investigate the preoperative detectability of the length of the proximal locking screw by radiological measurements.

PATIENTS AND METHODS

Between April 2020 and June 2021, a total of 50 patients (42 males, 8 females; mean age: 38.1±14.3 years; range, 18 to 60 years) who were suspected of vascular injury after gunshot or stab wounds and underwent lower extremity computed tomography angiography (CTA) from the local institution's database were included in the study. The distances of the femoral neurovascular structures (FNVS) and sciatic nerve (SN) to the femur were measured in the sections determined in the anteroposterior and medial-lateral planes. The anteroposterior length of the femur was measured in selected sections to estimate the appropriate length of the proximal locking screw.

RESULTS

The level at which FNVS and SN were closest to the femur in the medial-lateral plane was inferior to lesser trochanter (LT) 1 cm. The mean AP femur length at the level of the LT was 36.3±2.8 mm, at the level of inferior to LT 1 cm was 34.1±2.8 mm, at the level of superior to LT 1 cm was 38.6±3.7 mm.

CONCLUSION

In retrograde femoral nailing, the safest level in terms of screw placement is 1 cm above the LT. Additionally, the optimal screw length is 40 mm at the level of the LT and 1 cm superior it, whereas it is 35 mm at the level of the LT and 1 cm inferior to it.

A Single Proximal Interlocking Bolt May Be Sufficient for Retrograde Nailing of Extra-articular Femur Fractures

OBJECTIVE

To evaluate whether a single proximal interlocking bolt was sufficient during the treatment of extra-articular femur fractures with retrograde medullary nailing.

DESIGN

Retrospective comparative study.

SETTING

Academic Level 1 trauma center.

PATIENTS

The study included 136 patients with extra-articular femur fractures treated with retrograde medullary nailing who met inclusion and follow-up criteria.

INTERVENTION

The intervention included surgical treatment for a femur fracture with retrograde medullary nailing, with comparisons made between those treated with a single proximal interlocking (1 IL) bolt and those treated with 2 proximal interlocking bolts (2 IL).

MAIN OUTCOME MEASUREMENT

The main outcome measurements were as follows: (1) rate of nonunion and (2) rate of catastrophic implant failure.

RESULTS

There was no difference in the rate of nonunion requiring surgical intervention between the 2 groups. There were no catastrophic failures in either group.

CONCLUSIONS

A single proximal interlocking bolt may be sufficient when using retrograde nailing for the treatment of extra-articular femur fractures.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Excessively long interfragmentary screws for posterior wall acetabular fractures can predict intra-articular penetration

BACKGROUND

The fixation of posterior wall acetabular fractures often utilizes interfragmentary screws with varying length. Intricate pelvic anatomy and overhanging greater trochanter make obtaining proper screw trajectory difficult. A large measurement may represent aberrant trajectory and breach of the articular surface. This study aims to identify a preferred maximum screw length that avoids intra-articular penetration.

HYPOTHESIS

We hypothesized that a screw measured 40 millimeters or longer has a high likelihood of being intra-articular.

PATIENTS AND METHODS

A retrospective review included CT scans of 151 consecutive patients collected at a level-1 trauma center was analyzed by two observers. On axial imaging, a straight line was measured at the largest extraarticular portion of the posterior wall simulating ideal screw placement. Another line was measured tangent to the articular surface simulating longest possible extraarticular screw. Measurements were taken at 2-millimeter increments.

RESULTS

The intra-class correlation coefficient between both observers was excellent (0.75-1.00) for most recorded values. The maximum mean length for straight line measured (m=32.18mm, SD=3.74) which was smaller than the mean length for tangent line (m=38.44, SD=4.29). Exploratory multivariate logistic regression analyses demonstrated increased height, age, and acetabular version were associated with larger measurements greater than 40mm (p<0.05).

DISCUSSION

This study demonstrates that most acetabular posterior walls cannot accommodate a 40 millimeter lag screw. If the measured drill hole is greater than this length, then careful reconsideration of the screw trajectory is warranted to ensure the screw is not intra-articular. Older and taller patients may be able to accommodate longer screws.

LEVEL OF EVIDENCE

III.

Predictors of Symptomatic Implant Removal After Open Reduction and Internal Fixation of Tibial Plateau Fractures: A Retrospective Case-Control Study

A retrospective case-control study was conducted at a level I trauma center to assess whether radiographic details of tibial plateau fixation can predict symptomatic implant removal. Nine hundred fifty-one tibial plateau fractures were treated with open reduction and internal fixation from 2007 to 2016. Eighty-two (9%) were treated with implant removal for localized pain over the implant. A control group was selected from the remaining patients using cumulative sampling. Records and radiographs were reviewed for predictors hypothesized to be associated with implant removal. Based on the authors' multivariable model, implant removal was associated with each additional protruding screw (adjusted odds ratio, 1.32; 95% confidence interval, 1.13-1.55; P<.001), bicondylar fractures (adjusted odds ratio, 2.13; 95% confidence interval, 1.11-4.11; P=.02), and lower body mass index (P=.05). Associations that approached significance were observed with decreased age (adjusted odds ratio, 0.82 per 10 years; 95% confidence interval, 0.66-1.01; P=.06) and closed fractures (adjusted odds ratio, 0.34; 95% confidence interval, 0.10-1.19; P=.09). The model discriminated fractures requiring implant removal with moderate accuracy (area under the curve=0.71). Each additional screw that radiographically protrudes beyond the far cortex increases the odds of symptomatic implant removal by 32%. Bicondylar fractures and lower body mass index are also associated with symptomatic implant removal. These findings might help inform patients and guide fixation techniques to reduce the likelihood of symptomatic implant removal. [Orthopedics. 2020;43(3):161-167.].