Salvaging a stripped drive connection when removing screws

Screw stripping and its prevention in the hexagonal socket of 3.5-mm titanium locking screws

There have been several reports about the difficulties in removing 3.5-mm titanium locking screws from plates due to the stripping or rounding of the hexagonal screw socket. We investigated whether stripping the locking screw sockets can be prevented by using different screwdrivers or interposing materials into the socket during removal. We overtightened 120 3.5-mm titanium locking screws (Depuy Synthes, Paoli, PA) equally into locking plates on sawbone tibia models, applying a uniform torque of 4.5 Nm, exceeding the recommended torque of 1.5 Nm. Twenty screws each were removed using a straight-handle 2.5-mm screwdriver, T-handle screwdriver, hex key wrench, and straight-handle screwdriver with a non-dominant hand. In addition, 20 screws were removed using foil from a suture packet inserted into the screw socket or using parts of a latex glove inserted into the screw socket. The incidence rates of screw stripping using the straight-handle screwdriver, T-handle screwdriver, hex key wrench, non-dominant hand, foil interposition, and latex glove interposition were 75%, 40%, 35%, 90%, 60%, and 70%, respectively. When a T-handle screwdriver or hex key wrench was used, the probability of screw stripping was 4.50 times (odds ratio = 4.50, 95% confidence interval = 1.17 to 17.37, p = 0.03) and 5.57 times (odds ratio = 5.57, 95% confidence interval = 1.42 to 21.56, p = 0.01) lower than that with the straight-handle screwdriver, respectively. Foil or latex glove interpositions did not prevent screw stripping. Thus, in the current experimental study, T-handle screwdriver or hex key wrench usage decreased the incidence rate of screw stripping during removal compared to straight-handle screwdriver use.

Saw transection of retained compression screws with damaged heads instead of removal in revision first metatarsal osteotomy: a technique tip

Distal first metatarsal osteotomy is performed to correct hallux valgus. The surgery is being performed throughout the UK in increasing numbers. The osteotomies used are commonly fixed with one or two variable pitch compression screws. Recurrence of the deformity or inadequate correction in the primary surgery may require revision osteotomy which necessitates removal of previous screws. Revision rates for scarf osteotomy have been reported at 5%. Removal of screws can be challenging as they are often buried in bone and/or the screw heads can get damaged even despite meticulous preparation. Various techniques for removal of damaged screws are described, which require additional equipment and may result in significant loss of the host bone. We describe another technique where a standard Stryker TPS sagittal saw and saw blade (Kalamazoo, USA) are used to cut through the shaft of the compression screws in line with the planned revision osteotomy. We have successfully performed this on two occasions with good results, and describe our experience of using this technique which eliminates the need for complex over drilling procedures often required for removing stripped and retained screws.

New Technique for Removal of Screws With Damaged Heads

Removal of orthopedic implants may sometimes be difficult because of ongrowth of new bone. Titanium screws can become encased or stripped during the process of initial open reduction and internal fixation or at the time of hardware removal. Difficulty in removing screws from a locking plate is particularly well-known. Two patients with tibial and femoral diaphyseal fractures were treated using a locking plate or an intramedullary nail. However, after fracture healing, it was difficult to remove the locking screw or reconstruction screws because of damage to the heads. The stripped reconstruction screw was successfully removed employing the authors' so-called parallel planes technique. In this method, a high-speed diamond-tipped burr is applied to opposite sides of the screw head to form 2 parallel faces located slightly away from the recess of the screw head. The 2 faces can then be grasped solidly with locking pliers, allowing removal of the implant by unscrewing it with a gentle upward pulling action. The locking plate was cut from the plate edge to the edge of the screw hole. While making these radial cuts in the plates, the authors were careful not to extend the blade into the screw head. After removal of the locking plate from the screw, the authors were able to extract the jammed screw uneventfully using this technique. This technique can be performed without difficulty and does not require a special device. It is a useful option for extraction of damaged screws. [Orthopedics. 2017; 40(5):e911-e914.].

Difficulty in locking head screw removal

BACKGROUND

Locking plates are an internal fixation material useful in the treatment of bone fractures, which provides effective stabilization between the plate and locking head screws (LHSs) via the locking mechanism. However, difficulty in removing LHSs is relatively common, and such cases can require long surgical procedures or use of special removal equipment. The purpose of this study was to report the incidence and risk factors for difficult removal of LHSs.

METHODS

During the 5-year-6-month period from April 2006 to September 2011, 83 locking plates containing a total of 482 LHSs were removed in 80 patients at our institution. Out of 482 LHSs, there were 118 LHSs with a 2.4-2.7 mm diameter, 308 LHSs with a 3.5 mm diameter and 56 LHSs with a 5.0 mm diameter. The incidence of removal difficulty was examined on the basis of screw diameter. In addition, the risk factors were assessed in only LHSs with a 3.5 mm diameter. LHSs with a 3.5 mm diameter were divided into 2 groups, the difficult removal group and the easy removal group, and the data were examined based on age, sex, time between insertion and removal, and screw position. The incidence of removal difficulty in LHSs with a 3.5 mm diameter was examined every 6 months between insertion and removal.

RESULTS

Difficulty in removal was encountered in none (0 %) of 118 LHSs with a 2.4-2.7 mm diameter, 15 (4.9 %) of 308 LHSs with a 3.5 mm diameter, and none (0 %) of 56 LHSs with a 5.0 mm diameter. In only LHSs with a 3.5 mm diameter, the mean ages of the patients in the difficult removal group and the easy removal group were 32.1 and 45.6 years, respectively. The average time between insertion and removal in the difficult removal group and the easy removal group was 529.2 and 389.2 days, respectively. There was a statistically significant difference in age and time between insertion and removal. Removal was difficult in 15 (9.1 %) of 165 LHSs with a 3.5 mm diameter in those with >1 year between insertion and removal.

CONCLUSION

This study suggests that (1) the use of LHSs with a 3.5 mm diameter is a necessary condition for difficulty in screw removal, and that (2) longer time from internal fixation to removal, and (3) younger age, are risk factors for it. When removing LHSs with a 3.5 mm diameter, appropriate instruments and sufficient training are necessary.

Locking Compression Plates are more difficult to remove than conventional non-locking plates

PURPOSE

Locking Compression Plates (LCPs) have been introduced in the last decade. Clinicians have the impression that hardware removal of LCPs are more difficult and associated with more complications than conventional (non-locking) plates. Therefore, this study compares the complication rates of Locking Compression Plate (LCP) removal and conventional non-locking plate removal.

PATIENTS AND METHODS

Patients who underwent open reduction and internal fixation and subsequent hardware removal at the Department of Trauma Surgery at our Level 1 Trauma Centre between 1993 and 2007 were included through the hospital's information system. The primary outcome measure was the occurrence of complications during implant removal.

RESULTS

A total of 210 patients were included. The females were significantly older than the males [median age, 51.5 vs. 42.6 years (p < 0.001)]. The median operation time of LCP removal was significantly longer than the operation time of non-locking plate removal (72 vs. 54 min, p < 0.001). In the total study population, complications during implant removal occurred in 25 patients (11.9%). The complication rate of conventional non-locking plate removal was 2.5%. The complication rate of LCP removal was significantly higher (17.7%, p = 0.001).

CONCLUSION

LCP removal is associated with significantly more complications than conventional non-locking plate removal. The indication for removal of locking compression should be made cautiously, and surgical instruments for LCP removal should be optimized.

Difficulties encountered removing locked plates

INTRODUCTION

Locked plates are commonly used to obtain fixation in periarticular and comminuted fractures. Their use has also gained popularity in repairing fractures in osteoporotic bone. These plates provide stable fixation and promote biological healing. Over the last 3 years, we have used over 150 locked plates with varying success to fix periarticular fractures involving mainly the knee and ankle. In this study, we report our clinical experience and the difficulties encountered when removing locked plates in adult patients with a variety of indications including implant failure, infection, non-union and a palpable symptomatic implant.

METHODS

A retrospective analysis was performed of patients enrolled prospectively into a database. Included in the study were 36 consecutive adult patients who each underwent the procedure of locked plate removal in a single inner city level 1 trauma centre. Data collected included primary indication for fixation, indication for implant removal, time of the implant in situ, grade of operating surgeon and difficulties encountered during the procedure.

RESULTS

Implant removal was associated with a complication rate of 47%. The major problems encountered were difficulty in removing the locked screws and the implant itself. A total of ten cold welded screws were found in eight cases. Removal was facilitated by high speed metal cutting burrs and screw removal sets in all but one case, where a decision was made to leave the plate in situ.

CONCLUSIONS

The majority of studies investigating implant removal and problems encountered in doing so report a relatively high complication rate. With the advent of locking plates and their growing popularity, difficulties are now being seen intraoperatively when removing them. There is a paucity of data, however, specifically directed at locking plate removal. We recommend that surgeons should be aware of the potential complications while removing locked plates. Fluoroscopic control and all available extra equipment (mainly metal cutting burrs and screw removal sets) should be available in theatre.

[Removal of plates and screws. Tips and tricks for problematic cases]

BACKGROUND

This overview article addresses the different ways of explanting plates and screws. Once the decision has been taken to remove plates and screws, the situation is resolved by skilled performance of surgical procedures.

METHOD

In particular, tips and tricks are offered on how to deal with difficult explantations. In general, implant removal is straightforward and without complications. Special techniques, instruments, tips and tricks are important when implant removal becomes problematic due to screw damage, immovable implants, instrument breakage and suchlike.

CONCLUSION

This article describes procedures that will put the surgeon on a direct route to implant removal. Keeping strictly to the pathway will inevitably turn problematic implant removal into a straightforward procedure.

Removal of locking plates: new implant, new challenges and new solutions

Removal of locking plates in many ways poses novel challenges compared to conventional plates. None of the techniques described for the removal of locking plates are adequate for all situations. We report our experience of 27 patients from whom a total of 33 locking plates were removed. We also describe a novel technique for the removal of locking plates which in our experience could be used in most of these patients because it is appropriate for all situations and, from a technical point of view, is easy to use. Our new technique consists of removing the problematic locking screw by cutting the plate on both sides of the screw hole and using the screw head-plate hole unit for removal. We analyzed all these patients for the location of the plate, number of locking screws, time of implant removal since the initial surgery, reason for removal of the plate, nature of the difficulties encountered during surgery, and any perioperative complications. A total of 43 (17.34%) screws were difficult to remove. Twenty screws were found to be stripped, 15 were jammed and 8 were broken. Fourteen of the 20 stripped screws and all 15 jammed screws were removed using our technique. We found this technique of locking plate removal to be very versatile and useful in most of the cases in which removal was difficult. At the same time, it also causes less damage to the bone compared to other techniques.

The concept of locking plates

After a short historical review of locking bone plates since their inception more than a century ago to the success of the concept less than 15 years ago with today's plates, the authors present the main locking mechanisms in use. In the two broad categories - plates with fixed angulation and those with variable angulation - the screw head is locked in the plate with a locknut by screwing in a threaded chamber on the plate or by screwing through an adapted ring. The authors then provide a concrete explanation, based on simple mechanical models, of the fundamental differences between conventional bone plates and locking plates and why a locking screw system presents greater resistance at disassembly, detailing the role played by the position and number of screws. The advantages of epiphyseal fixation are then discussed, including in cases of mediocre-quality bone. For teaching purposes, the authors also present assembly with an apple fixed with five locking screws withstanding a 47-kg axial load with no resulting disassembly. The principles of plate placement are detailed for both the epiphysis and diaphysis, including the number and position of screws and respect of the soft tissues, with the greatest success assured by the minimally invasive and even percutaneous techniques. The authors then present the advantages of locking plates in fixation of periprosthetic fractures where conventional osteosynthesis often encounters limited success. Based on simplified theoretical cases, the economic impact in France of this type of implant is discussed, showing that on average it accounts for less than 10% of the overall cost of this pathology to society. Finally, the possible problems of material ablation are discussed as well as the means to remediate these problems.

Technical difficulties of removal of locking screw after locking compression plating

INTRODUCTION

As there are few reports on the difficulties of removing the locking compression plate (LCP), we prospectively investigated the incidence and difficulties in 58 patients in whom various types of LCPs were taken.

METHODS

From January 2004 to December 2007, we have removed 159 5.0-self tapping locking screws and 279 3.5- self tapping locking screws. All of the operations were performed by experienced trauma surgeons. All of the screws were inserted with the use of torque limiting attachment according to the manufacturer's recommendation. During the same period of time we have removed 198 AO-3.5 cortical and 4.0 cancellous screws from various sites.

RESULTS

All of 159 5.0-self tapping locking screws were removed without difficulties. A total of 24 out of 279 3.5- self tapping locking screws were removed with many difficulties due to the stripping of the hexagonal recess. The use of conical extraction screw which was developed especially for the removal of stripped locking screws was successful in only six screws. We have removed plates by cutting the plate with metal cutting saw. We describe useful technical trick to remove the plate when there is only one screw left stripped. Compared to the locking screws, only one of 198 3.5-cortical screws was stripped.

CONCLUSION

Care should be taken at the time of removal of the locking compression plate, especially for the 3.5-locking screws.

Complications of locking plate fixation in complex proximal tibia injuries

OBJECTIVES

To report the complications and pitfalls in the treatment of complex injuries of the proximal tibia when locking plates are used.

DESIGN, SETTING, AND PATIENTS

This was a retrospective case series conducted at a university Level I trauma center. Thirty-seven patients with complex proximal tibia fractures (41C1, 41C2, 41C3, 41A2, 42A2) were treated with locking plates.

INTERVENTION

All fractures were treated with locking plates (Less Invasive Stabilization System (LISS); Synthes, Paoli, PA).

MAIN OUTCOME MEASUREMENTS

Healing, alignment, infection, and other complications.

RESULTS

Twelve fractures (32%) healed without any complications. Eight patients (22%) developed deep infections that required operative debridements, and 5 of them had a hardware removal; 1 eventually required an above-knee amputation. Eight cases (22%) had postoperative malalignment, with hyperextension as the most common deformity. Three cases (8%) had loss of alignment into varus during healing. Other complications were 1 superficial wound dehiscence, 1 delayed soft-tissue breakdown, 4 hardware irritations, 1 peroneal nerve injury at the distal part of a 9-hole plate, 1 tibial tubercle nonunion, and 1 postoperative compartment syndrome.

CONCLUSION

The complication rate, particularly infection, was higher than in previous reports. Other complications such as hardware prominence, malalignment, and loss of alignment were similar to those of historical controls. Some of the complications may reflect the techniques that were used and should decrease with more experience; however, some may be inherent in the treatment of high-energy fractures using locking plates.

Removal of the less invasive stabilization system

The Less Invasive Stabilization System (LISS; Synthes; Paoli, PA) is a newly developed locking plate that has been used for fixation of distal femoral supracondylar and proximal tibial fractures. The early clinical results have been encouraging; however, there is little information available on the removal of these implants. Frequent stripping of the locking screws has been found by our group when removal is attempted. Our approach to this problem is described.