Liston Bone Cutting Forceps: Straight vs Angled Jaw Selection

Straight or angled?

It is the only real decision when ordering this instrument, and most catalogues answer it with a shrug — both are listed, no guidance given. The choice is not preference. It is determined by how deep the bone sits and which direction the cut has to travel.

What the Instrument Is

Liston bone cutting forceps are a single-action cutting instrument: two opposed bevelled blades on a spring-loaded scissor joint, closed by direct hand pressure. They divide small and medium bone — ribs, phalanges, metatarsals, small fragments during debridement, and bone spikes left after a fracture is reduced.

Single action means one squeeze equals one cut, with the mechanical advantage coming entirely from handle length. This is the important limitation. Above roughly 20 cm handle length and a certain bone density, single-action cutting stops being practical and you want the double-action Liston-Stille pattern instead, which adds a second pivot and roughly doubles the force at the jaws for the same grip effort.

The blades are bevelled on both sides and meet edge to edge — they shear bone rather than crush it. That distinguishes them from a rongeur, which bites and removes a fragment, and from a chisel, which splits along a plane.

Straight Versus Angled: How to Choose

The straight pattern cuts in the plane of the handles. Use it when the bone is superficial and you can approach it square-on: rib ends at the costal margin, phalanges, exposed fragment edges, most amputation-level work on the forearm and lower leg.

The angled pattern — described in catalogues as “angled on flat” or “angled on side” depending on which way the bend runs — offsets the jaws from the handle axis. That does two things. It lets the jaws reach bone lying deeper than the surrounding soft tissue without the handles fouling the wound edge, and it keeps the surgeon’s hand out of the line of sight over the cut.

A practical rule: if you find yourself rotating your wrist past a comfortable position to line the blades up with the cut, you needed the angled pattern. Forcing a straight instrument into an awkward approach is how blades get loaded off-axis, and off-axis loading is what springs the joint.

Sizes and Jaw Dimensions

Overall lengths for single-action patterns run from about 140 mm (5½ inch) to 220 mm (8¾ inch). Jaw widths are commonly quoted between 15 mm and 24 mm. The relationship worth remembering is that jaw width sets the maximum bone diameter you can take in one clean pass — trying to cut bone wider than the jaw span means repositioning mid-cut, which leaves a stepped, splintered edge.

For general theatre stock, a 170 mm straight and a 190 mm angled cover the majority of cases, with a 250 mm double-action pattern held for heavier work.

Steel, Hardness and Blade Life

Cutting bone is the most abusive thing you can ask a hand instrument to do. The blades need hardness for edge retention while the handles need enough toughness to absorb repeated spring loading without cracking.

We manufacture these from martensitic stainless steel to ISO 7153-1 — typically AISI 420 for the body, hardened and tempered so the cutting edges run around 52–56 HRC while the spring section stays tougher. Some heavy patterns are supplied with tungsten carbide inserts brazed to the blade faces, which extends usable edge life substantially at higher cost. TC inserts are worth it in a high-turnover orthopaedic or thoracic list; on an occasional-use set they rarely pay back.

Edge condition is checked the same way for every cutting instrument in the tray. Hold the blades to the light closed — any visible line of daylight along the cutting edges means they no longer meet and the instrument crushes rather than cuts. Crushed bone edges heal poorly and shed more debris into the wound, so this is a clinical check, not just an asset-care one. The same principle applies across the whole cutting family; our comparison of bone rongeur patterns covers where biting instruments take over from shearing ones.

Where These Forceps Stop and Another Instrument Starts

Bone division is a small family of instruments with overlapping catalogue descriptions and very little overlap in actual use. Knowing the boundaries prevents both the wrong purchase and the wrong instrument reaching for the wrong job on the table.

• Rongeur. Bites and removes a fragment, leaving a defect. Use when the objective is to take bone away — nibbling back a rough edge, decompressing, contouring. A cutting forceps divides; a rongeur excavates. Our Kerrison and Leksell rongeur comparison covers the patterns.
• Osteotome or chisel. Splits along a plane under mallet force. Use when you need a controlled directional cut through cancellous bone, or when the cut surface must be flat for apposition. Cutting forceps cannot produce a planar cut.
• Bone saw, hand or powered. Use for cuts through cortical bone where the cut face must be smooth and the kerf predictable — arthroplasty resections, corrective osteotomies. Shearing forceps leave a crushed and slightly splayed edge that is unsuitable where two surfaces must sit flush.
• Wire and pin cutter. Use for anything metallic. Never a bone instrument.

The short version: forceps for dividing accessible bone quickly, saw for a precise surface, osteotome for a plane, rongeur for removal.

Care and Reprocessing

Bone debris packs into the joint and behind the blade shoulders, and it sets hard if allowed to dry. Immediate enzymatic soak, brush the joint open, then ultrasonic clean. Lubricate the box joint with instrument milk after every cycle — a dry joint on a spring instrument stiffens quickly and the extra grip force needed goes straight into the blades as off-axis load.

Store and sterilise with the handles open so the spring is unloaded. Do not use these on wire, pins or implants. Cutting a K-wire with bone forceps will notch the blade permanently, and it is the single most common way a good instrument is written off early. Keep a dedicated wire cutter in the set. If you are choosing between powered and manual bone division for a given procedure, our note on bone drills versus bone saws covers where hand instruments remain the better answer.

Sourcing

Specify four things: pattern (Liston or Liston-Stille), action (single or double), jaw orientation (straight, angled on flat, angled on side), and overall length. Add “TC” if you want carbide inserts.

Fizza Surgical has manufactured bone cutting instruments in Sialkot since 1980 under ISO 13485, CE marked, with batch-traceable material certificates. The range sits in our bone surgery instrument catalogue, alongside rongeurs, osteotomes and elevators for building a complete orthopaedic tray.