Teaching Cortical-Screw Tightening: A Simple, Affordable, Torque-Directed Training Protocol Improves Resident Performance

A novel acoustic emission screwdriver reduces surgeons´ cancellous screw stripping rate - A biomechanical study

BACKGROUND

Orthopedic surgeons refine their torque sensitive skills from tightening cancellous screws. Still, experienced surgeons exhibit surprisingly high screw stripping rates in osteopenic cancellous bone. Whether Acoustic-Emission technology, detecting energy waves from microstructural damage during screw purchase, can reduce these rates is unclear. Our aim was to evaluate if surgeons, irrespective of their experience, reduced cancellous screw stripping rate by combining their skills with feedback from an innovative Acoustic-Emission screwdriver.

METHODS

Thirteen orthopedic surgeons with 0-23 years´ experience inserted 468 large fragment cancellous screws through plates into synthetic osteoporotic bone. The 1st stage, surgeons tightened 9 screws each without Acoustic-Emission feedback. The 2nd stage, each tightened 18 screws using the Acoustic-Emission feedback modified screwdriver. The last stage, surgeons tightened 9 screws each, again without Acoustic-Emission feedback. A strain gauge on the screwdriver was used to verify screw stripping.

FINDINGS

Surgeons stripped 36 out of 115 screws (31 %) in stage 1, 37 out of 227 screws (16 %) in stage 2, and 26 out of 114 screws (23 %) in stage 3. A significant reduced screw stripping rate was found in stage 2 compared to in stage 1 (p < 0.001). Neither the individual surgeon nor experience of the surgeon contributed to screw stripping probability in a mixed effect logistical regression model.

INTERPRETATIONS

Acoustic-Emission technology is superior to the torque sensitive skills of surgeons, demonstrating its potential to assist surgeons in real time, regardless of their experience, in reducing screw stripping rates in cancellous bone.

Quantifying the Opportunity Cost of Resident Involvement in Academic Orthopedic Shoulder Arthroplasty: A Matched - Pair Analysis

Background

There is minimal work defining the economic impact of resident participation in shoulder arthroplasty. Thus, this study quantified the opportunity cost of resident participation in total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) by determining differences in operative time, relative value units (RVUs)/hour, and RVUs/case.

Methods

A retrospective analysis of shoulder arthroplasty procedures were identified from the ACS-NSQIP database from 2006 to 2014 using CPT codes. Demographic, comorbidity, preoperative laboratory data and surgical procedure were used to develop matched cohorts. Mean differences in operative time, RVUs/case and RVUs/hour between attending-only (AO) cases and cases with resident involvement (RI) were examined. Cost analysis was performed to identify differences in RVUs generated per hour in dollars/case.

Results

A total of 1786 AO and 1102 RI cases were identified. With the exception of PGY-3 and PGY-4 cases, RI cases had lower mean operative times compared to AO cases. The cost of RI was highest for PGY-3 ($199.87 per case) and PGY-4 ($9 .2 9) residents with all other postgraduate years providing a cost reduction.

Discussion

Involvement of residents was associated with shorter operative times leading to a savings of $29.64 per case. Involvement of intermediate-level (PGY-3) residents were associated with increased costs that ultimately decreased as residents became more senior.

Risks of injury in distal metatarsal minimally invasive osteotomy when comparing standard and modified techniques: A cadaveric study

BACKGROUND

The objectives of the study were to evaluate the structures at risk in distal metatarsal mini-invasive osteotomy (DMMO) and to compare standard and intraosseous approaches.

METHODS

DMMO was performed on the second and fourth metatarsals of 11 fresh-frozen cadaveric specimens. The standard technique was performed in 11 metatarsals. It was then compared to a modified intraosseous technique that entails starting inside the bone in 11 other metatarsals. The cadavers were dissected to identify unintentional injury to soft tissue structures.

RESULTS

In the standard group the most injured structures were the metatarsal joint capsules (MJC) (27%), extensor digitorum longus (EDL) (18%), and extensor digitorum brevis (EDB) (9%). The modified intraosseous group injured the EDL (27%), not the MJC (0%) and the EDB (0%). Distances between osteotomies and the dorsal metatarsal head articular surface (DMHAS) were 6.08 ± 3.99 mm in the standard and 9.92 ± 3.42 mm in the modified (p = 0.02).

CONCLUSION

The DMMO techniques most frequently injured the EDL. Intra-articular positioning of the osteotomy was more observed in the standard. Overall, it appears the modified method could be an alternative to the standard DMMO.

CLINICAL RELEVANCE

The modified minimally invasive DMMO has a comparable rate of potential iatrogenic injuries. This intraosseous procedure may present as an option when planning surgery to the lesser metatarsals.

LEVEL OF EVIDENCE

Level III. Comparative Cadaveric Study.

Redesigning Metal Interference Screws Can Improve Ease of Insertion While Maintaining Fixation of Soft-Tissue Anterior Cruciate Ligament Reconstruction Grafts

Purpose

To compare the fixation strength and loads on insertion of a titanium alloy interference screw with a modified tip against a conventional titanium interference screw.

Methods

Slippage of bovine digital extensor tendons (as substitutes for human tendon grafts) under cyclic loading and interference fixation strength under a pullout test were recorded in 10 cadaveric knees, with 2 tunnels drilled in each femur and tibia to provide pair-wise comparisons between the modified-tip screw (MS) and conventional screw (CS). To analyze screw insertion, 10 surgeons blindly inserted pairs of the MS and CS into bone-substitute blocks (with polyester shoelaces as graft substitutes), with insertion loads measured using a force/torque sensor.

Results

No differences were found between the MS and CS either in graft slippage from the femur (P = .661) or tibia (P = .950) or in ultimate load to failure from the femur (P = .952) or tibia (P = .126). On insertion, the MS required less axial force application (78 ± 38 N, P = .001) and fewer attempted turns (2 ± 1, P < .001) to engage with the bone tunnel than the CS (99 ± 43 N and 4 ± 4, respectively). In 90% of the paired insertion tests, the screw identified by the surgeon as being easier to initially insert was the MS.

Conclusions

The MS was found to be easier to engage with the bone tunnel and initially insert than the CS while still achieving similar immediate postsurgical fixation strength.

Clinical Relevance

The study shows that screw designs can be improved to ease insertion into a bone tunnel, which should reduce any likelihood of ligament reconstruction graft damage.

Quantifying the Opportunity Cost of Resident Involvement in Academic Orthopaedic Sports Medicine: A Matched-Pair Analysis

PURPOSE

To quantify the cost of resident involvement in academic sports medicine by examining differences in operative time, relative value units (RVUs) per case, and RVUs per hour between attending-only cases and cases with resident involvement.

METHODS

A retrospective analysis of common sports medicine procedures identified by Current Procedural Terminology code was performed using data from the American College of Surgeons National Surgical Quality Improvement Program database from 2006 to 2015. Matched cohorts were generated based on demographic variables, comorbidities, preoperative laboratory values, and surgical procedures. Bivariate analysis examined mean differences in operative time, RVUs per case, and RVUs per hour between attending-only cases and cases with resident involvement. A cost analysis was performed to quantify differences in RVUs generated per hour in terms of dollars per case.

RESULTS

A total of 14,840 attending-only cases and 2,230 resident-involved cases were used to generate 2 matched cohorts (N = 4,460). Resident cases had greater mean operative times than attending-only cases, with operative time increasing as residents became more senior (P < .01). Residents participated in cases with larger mean RVUs per case (P < .01). Cases with lone attendings showed greater RVUs per hour (P < .01). The cost of resident involvement increased nearly 8-fold from postgraduate year 1 to postgraduate year 6 residents ($25.70 vs $200.07).

CONCLUSIONS

In academic sports medicine, the involvement of resident physicians increases operative time. The associated decrease in attending physician efficiency in RVUs per hour equates to an average cost per case of $159.18, with costs increasing as residents become more senior.

LEVEL OF EVIDENCE

Level III, retrospective comparative trial.