News & Announcements

Authors

Alex J. Burnett, BS; Michael Moser, MD; Ryan P. Roach, MD; David Hagan, MD; Kevin W. Farmer, MD; Marissa Pazik, LAT, ATC, CSCS; and Joseph J. King, MD

Introduction

The Rockwood clavicle pin (Zimmer Biomet; Warsaw, Indiana) provides a viable alternative to plate fixation for young, active patients with simple displaced mid-shaft clavicle fractures (Figure 1).

Figure 1. Rockwood clavicle pin assembly (Source: DePuy Orthopaedics, 2001).

The best use of this implant is fixation of simple fractures in which good cortical contact and compression can be achieved. Although severe comminution is a contraindication, a small amount of comminution can be tolerated with the Rockwood clavicle pin, provided there is adequate bony contact to allow for compression.

Advantages and Disadvantages

The use of the Rockwood clavicle pin has several benefits for clavicular fixation:

• The Rockwood clavicle pin requires a smaller incision over the fracture compared with plate fixation. This results in a smaller scar, improved cosmesis, and less chance of numbness from cutaneous nerve injury.
• Use of an intramedullary pin requires less soft tissue stripping, resulting in better preservation of the periosteal blood supply.
• The patient has no residual hardware once the pin is removed. Plus, the number of stress risers in the bone is reduced because only 1 unicortical hole is needed. Hardware removal after plate fixation leaves multiple bicortical holes.
• Intramedullary fixation has been shown to provide a shorter time to union in clavicle fractures. [1]

Disadvantages to the use of the Rockwood clavicle pin include weaker initial fixation from an intramedullary device compared with plate fixation, as well as the inherent need for a second surgery to remove the pin.

Biomechanical studies have shown that intramedullary pin fixation provides less rotational stiffness and allows for more displacement at equal loads when compared with plate fixation. [2,3]

Technique

Access to the posterolateral shoulder is needed for Rockwood clavicle pin placement. Our preferred method is to use a beach chair positioner with the torso elevated about 45° to obtain adequate access to the posterior shoulder. This allows for access to the pin, as it is passed out of the posterolateral cortex, and for adequate exposure for fluoroscopy if desired (Figure 2). Alternatively, the procedure can be done with the patient supine and a bump under the ipsilateral paraspinal area.

Tip: Make sure there is adequate access to the posterolateral clavicle. A bump may be added under the scapula to aid in posterior access.

Figure 2. Patient is placed in the beach chair position with torso elevated to 45° and as close to the edge of the table as possible to allow easy access to the posterior shoulder.

After the fracture site is prepped and draped in a routine fashion, identify the fracture by palpation. If it is not palpable due to swelling, we recommend confirming the fracture location with fluoroscopy to help make a small incision overlying the fracture site.

There are 2 options for the incision:

• Curvilinear incision along Langer’s lines
• Longitudinal incision in line with the clavicle

A curvilinear incision has been shown to improve patient satisfaction with the scar appearance. However, 1 study found no difference in the experience of numbness or pain in patients with a curvilinear incision compared with patients who had a longitudinal incision. [4] Although predictable patterns of branching and locations where the supraclavicular nerve crosses the clavicle have been identified, no clinically relevant safe zone between the medial and lateral branches has been found. [5]

Figure 3. The patient is prepped and draped with adequate access to the posterior shoulder and marked with an incisional line over the fracture site.

Following incision, carry dissection down to expose the 2 fracture ends, removing all soft tissue and adhesions at the fracture site to maximize bone contact. We recommend a reduction at this time to confirm that there is enough exposure to reduce the fracture (Figure 4).

Figure 4. Satisfactory exposure is confirmed with reduction of the fracture.

Next, attention is turned to prepping the intramedullary canals.

The drill size is based on the size of the planned implant (Figure 5). We suggest using the smallest-diameter pin (2.5-mm pin with a 2.8-mm drill) with patients under 18 years old. For smaller patients, the 2.5-mm pin has 2 length options, and we suggest using the shorter pin.

In young adults, a larger diameter is preferable to increase the implant strength, but the diameter must be based on intramedullary canal size of the clavicle in each patient.

Figure 5. Rockwood clavicle pin diameters and lengths with associated drill bit diameters.

Drill the intramedullary canals of the medial and lateral fragments using power, and then tap by hand. The lateral fragment may be tapped under power if desired. When drilling the medial fragment, be sure to aim posteriorly and inferiorly to avoid breaching the anterior clavicular cortex. Fluoroscopy can be used to check the orientation of the drill and depth of the tap if needed (Figure 6).

Next, drill the lateral fragment, exiting through the posterolateral cortex. Aim inferiorly and anteriorly to obtain maximal purchase by exiting the clavicle as laterally as possible (Figure 7). This aim will also reduce the prominence of the lateral nut complex. Again, orientation can be checked fluoroscopically, if needed.

Tip: By aiming more inferior and anterior with the lateral drill as the lateral cortex is breached, the lateral nut complex will be less prominent. This can help prevent skin irritation and decrease the risk of skin breakdown prior to removal.

Figure 6. Tapping the medial fragment by hand.

Figure 7. Drilling the lateral fragment ensuring to aim inferiorly and anteriorly.

When tapping, be sure to tap at least 1 cm deeper into the lateral fragment and past the point at which you think the threads will engage medially to avoid incarceration. If significant resistance is encountered when tapping the fragments, we suggest sizing down to the next smallest-diameter implant to avoid difficulty with insertion.

Tip: When deciding which implant to use, measure the intramedullary canal diameter on radiographs to get an idea of the appropriate size.

Place the blunt medial end of the Rockwood clavicle pin into the drill. Drill the sharp lateral end through the lateral fragment, exiting through the posterolateral cortex (Figure 8). Make an incision in the skin overlying the posterolateral aspect of the pin. Remove the drill and place it on the lateral end of the pin. Back up the pin until it clears the medial fragment. The fracture is now reduced. Advance the pin into the medial fragment, securing the reduction.

Prior to placing the medial threads across the fracture, plan how deep the pin must go medially to get good purchase and to clear the fracture site. Of note, smaller patients have limited space for compression due to the threads ending laterally, which sometimes necessitates deeper placement (ie, more medial) in these patients.

Next, place the lateral locking nuts on the lateral end of the pin and cold-weld them in place at the appropriate length, which is based on the planned amount of medial advancement (Figure 9). Cut the pin before advancing the construct into its final position (Figure 10). Then advance the pin until the nut complex abuts the posterior cortex of the clavicle to compress the fracture site.

Figure 8. The pin is advanced through the lateral cortex and out of the incision made overlying the pin until the medial end clears the fracture site.

Figure 9. Cold-welding medial and lateral nuts together before the pin is cut flush with the lateral nut.

Figure 10. Advancing the final construct while holding the fracture reduction.

Alternatively, after cold-welding the nuts, advance the pin using the lateral wrench until the medial end of the pin meets the anterior cortex. Break the cold-welded nuts and advance the medial nut until it contacts the posterolateral cortex. Advance the lateral nut until it contacts the medial nut.

Next, back the construct out of the clavicle until the nuts clear the skin, using the medial nut wrench. Cold-weld the nuts together again, cut and file the pin, and advance the construct into its former and final position as the medial nut contacts the posterolateral cortex to allow for compression.

Final fluoroscopic images can be taken to confirm pin position and fracture reduction (Figure 11).

Figure 11. Final pin positioning and reduction seen with radiograph image taken at follow-up visit.

Postoperative Care

Postoperatively, keep the patient non-weight-bearing for 8 to 12 weeks until evidence of fracture healing is observed. Limit shoulder range of motion to no forward flexion or abduction past 90° for 6 weeks; shoulder rotation is not limited. Fracture healing can be followed with interval radiographs and clinical examinations.

Removal of the Rockwood clavicle pin typically occurs around 10 to 12 weeks postoperatively, with return to the operating room under general anesthesia.

Please note: Due to unknown reasons, Zimmer-Biomet has recently discontinued the manufacturing of the Rockwood Clavicle Pin. We are currently seeking out opportunities with other companies to make a similar implant with some improvements on the design.

Author Information

Alex J. Burnett, BS, is a medical student at the University of Florida College of Medicine in Gainsville.

Michael Moser, MD, is the Wayne Huizenga Professor of Sports Medicine and Division Chief for Orthopaedics and Sports Surgery in the Department of Orthopaedic Surgery and Sports Medicine at the University of Florida College of Medicine in Gainesville. He is also a team physician for the University of Florida Athletic Association.

Ryan P. Roach, MD, is Assistant Professor of Orthopaedics and Sports Surgery in the Department of Orthopaedic Surgery and Sports Medicine at the University of Florida College of Medicine in Gainesville. He is also a team physician for the University of Florida Athletic Association.

David Hagan, MD, is a resident in orthopaedic surgery at the University of Florida in Gainesville.

Kevin W. Farmer, MD, is Professor of Orthopaedics and Sports Surgery in the Department of Orthopaedic Surgery and Sports Medicine at the University of Florida College of Medicine in Gainesville. He is also a team physician for the University of Florida Athletic Association.

Joseph J. King, MD, is Associate Professor of Shoulder and Elbow Surgery in the Department of Orthopaedic Surgery and Sports Medicine at the University of Florida College of Medicine in Gainesville.

Marissa Pazik, LAT, ATC, CSCS, is Clinical Research Coordinator for Sports Medicine and Trauma in the Department of Orthopaedic Surgery and Sports Medicine at the University of Florida College of Medicine in Gainesville.

Disclosures: Mr. Burnett, Dr. Moser, Dr. Roach, Dr. Hagen, and Ms. Pazik have no disclosures relevant to this article. Dr. Farmer has disclosed that he is a paid consultant and speaker for Arthrex and that he is a paid consultant for Exactech, Inc. Dr. King has disclosed that he is a paid consultant for Exactech, Inc., and LinkBio Corp and that he has stock or stock options in Pacira Pharmaceuticals.

References

1. Gao Y, Chen W, Liu YJ, Li X, Wang HL, Chen ZY. Plating versus intramedullary fixation for mid-shaft clavicle fractures: a systemic review and meta-analysis. PeerJ. 2016 Feb 22;4:e1540.
2. Renfree T, Conrad B, Wright T. Biomechanical comparison of contemporary clavicle fixation devices. J Hand Surg Am. 2010 Apr;35(4):639-44.
3. Golish SR, Oliviero JA, Francke EI, Miller MD. A biomechanical study of plate versus intramedullary devices for midshaft clavicle fixation. J Orthop Surg Res. 2008 Jul 16;3:28.
4. Shukla DR, Rubenstein WJ, Barnes LA, Klion MJ, Gladstone JN, Kim JM, Cleeman E, Forsh DA, Parsons BO. The Influence of Incision Type on Patient Satisfaction After Plate Fixation of Clavicle Fractures. Orthop J Sports Med. 2017 Jun 22;5(6):2325967117712235.
5. Nathe T, Tseng S, Yoo B. The anatomy of the supraclavicular nerve during surgical approach to the clavicular shaft. Clin Orthop Relat Res. 2011 Mar;469(3):890-4.