A family of signaling proteins involved in bone formation; specific recombinant products have narrow indications and are not routine limb-lengthening supplements.

Aliases: bone morphogenetic protein, BMP-2, BMP-7

Bone density

The amount of mineral content per unit area or volume of bone.

Aliases: BMD, bone mineral density

Bone graft

Transplanted bone tissue used to repair, rebuild, or stimulate healing.

Aliases: allograft, synthetic graft

Bone healing

The biological process by which a cut or fractured bone repairs and restores its strength.

Aliases: bone repair

Bone stimulator

A device that delivers ultrasound or electromagnetic stimulation under a diagnosis- and product-specific plan.

Aliases: bone growth stimulator

C

Callus

Newly formed bone tissue that develops at a fracture or osteotomy site during healing.

Aliases: regenerate bone, regenerate

CAUTI

Catheter-associated urinary tract infection, a hospital-acquired infection risk after surgery.

Aliases: catheter-associated urinary tract infection

CLL (Cosmetic Leg Lengthening)

Limb lengthening performed primarily for height increase in individuals without significant medical deformity.

Aliases: cosmetic leg lengthening, stature lengthening

Compartment syndrome

A condition where swelling within a muscle compartment compresses blood vessels and nerves.

Consolidation

The biological process in which newly formed bone hardens and mineralizes.

Consolidation phase

The period after active lengthening ends during which the regenerate bone matures.

Contracture

Restricted joint motion caused by shortened or stiff soft tissues; severity and reversibility vary.

Aliases: joint contracture

Corticotomy

A bone-division technique intended to preserve the local biological environment as much as possible.

D

Delayed consolidation

A condition in which regenerate bone forms more slowly than expected.

DEXA Scan

Dual-energy X-ray absorptiometry, usually used to estimate areal bone mineral density; it is not a universal limb-lengthening eligibility test.

Aliases: DXA, bone density scan, dual-energy X-ray absorptiometry

DICOM file

The standard for storing and exchanging medical images together with their identifying and technical metadata.

Aliases: DICOM

Distraction osteogenesis

The biological process by which new bone tissue forms in a gradually widening gap.

Aliases: DO

Distraction phase

The period following surgery during which the bone segments are gradually separated.

Distraction rate

The speed at which bone segments are separated during the distraction phase.

Aliases: rate of distraction

Dorsiflexion

The movement of bending the foot upward toward the shin.

DVT (Deep Vein Thrombosis)

A blood clot that forms in a deep vein, typically in the leg.

Aliases: deep vein thrombosis

E

EFI

The time spent wearing an external fixator per centimeter of lengthening achieved.

Aliases: external fixator index

Equinus contracture (Ankle equinus)

A condition in which the ankle becomes restricted, causing the foot to point downward.

Aliases: ankle equinus

ERC (External Remote Control)

The handheld device used to activate the internal magnet in a PRECICE nail.

Aliases: external remote control

External fixator

A metal framework attached to the outside of the limb via pins or wires.

Aliases: exfix, external fixation

F

Fasciotomy

Emergency surgical release of a muscle compartment to relieve dangerous pressure buildup.

Fat embolism

A condition where fat particles enter the bloodstream and obstruct small blood vessels.

Aliases: fat embolism syndrome, FES

Femoral lengthening

A limb lengthening procedure performed on the femur (thigh bone).

Femur

The thigh bone; the longest and strongest bone in the human body, extending from the hip to the knee.

Aliases: thigh bone, femoral bone

Fibula

The thinner, lateral bone of the lower leg that runs parallel to the tibia.

Fibula migration

A positional shift of the fibula relative to the tibia, which can occur after tibial lengthening.

Fitbone

A family of motorized intramedullary lengthening systems made by Orthofix.

Forteo (teriparatide)

A brand of teriparatide, a prescription osteoporosis medicine; use for limb-lengthening regenerate is off-label and not standardized.

Aliases: teriparatide

Full weight-bearing (FWB)

A prescribed loading status with no weight limit through the limb; it does not necessarily mean safe independent walking.

Aliases: FWB

G

Gait

The manner or pattern of walking or moving on foot.

Aliases: walking pattern

Gastrocnemius

The large muscle of the posterior lower leg that forms the visible calf.

Aliases: calf muscle

Growth plate (Physis)

The area of cartilage near the end of long bones where new bone is produced during growth.

Aliases: physis

H

Hamstring

The group of three muscles at the back of the thigh that cross the hip and knee joints.

Aliases: hamstrings

Healing index (HI)

A time-per-length metric whose numerator and endpoint must be defined before studies can be compared.

Aliases: HI

Hexapod frame

A computerized external fixator using six adjustable struts between two rings for simultaneous multi-plane correction.

Humerus lengthening

A surgical procedure to increase the length of the upper arm bone.

I

Ilizarov frame

A circular external fixator consisting of rings connected by threaded rods, used for bone lengthening and deformity correction.

Aliases: Ilizarov apparatus, circular fixator

IM nail

A metal rod inserted into the hollow center of a long bone to stabilize and support it.

Aliases: intramedullary nail, intramedullary rod

Implant failure

Mechanical breakdown of the internal lengthening nail or its components.

Aliases: nail failure, mechanical failure

Internal fixation

A surgical method of stabilizing a bone using devices (nails, plates, screws) implanted entirely within the body.

Internal lengthening nail (ILN)

A motorized intramedullary device inserted inside the bone to drive lengthening.

Aliases: ILN

Intramedullary

Located within the medullary canal of a bone.

Aliases: IM

IT band (Iliotibial band)

A thick band of fibrous tissue running along the outside of the thigh from hip to tibia.

Aliases: iliotibial band, ITB

J

Joint stiffness

Reduced range of motion in a joint; trend, cause, and functional effect matter.

L

Latency period

The prescribed interval between bone division and the start of distraction; duration is protocol- and patient-specific.

Aliases: latency phase

LATN (Lengthening And Then Nailing)

A two-stage technique using an external fixator during distraction, followed by an internal nail.

Aliases: lengthening and then nailing

Lengthening phase

The stage during which gradual distraction is applied to stimulate new bone formation.

Aliases: distraction phase

LLD (Leg Length Discrepancy)

A measurable difference in length between the two legs.

Aliases: leg length discrepancy, limb length discrepancy

Locking screw

A screw inserted through the bone and the intramedullary nail to secure the nail in position.

Aliases: interlocking screw

LON (Lengthening Over Nail)

A hybrid lengthening technique using both an internal nail and an external fixator.

Aliases: lengthening over nail

M

Malalignment

Improper alignment of a bone resulting in angular, rotational, or length deformity.

Mechanical axis

Imaginary line representing weight-bearing alignment from hip to ankle.

Medullary canal

The hollow inner channel of a long bone that contains bone marrow.

Aliases: intramedullary canal, medullary cavity

Monolateral lengthening

External fixation attached to only one side of the limb to gradually lengthen the bone.

Aliases: monolateral fixator

N

Nail removal

A secondary surgical procedure to remove the intramedullary nail after the bone has fully consolidated.

Aliases: hardware removal

Nerve decompression

A surgical procedure to relieve pressure on a compressed nerve.

Neuropathic pain

Pain caused by damage to or dysfunction of peripheral nerves, sometimes experienced during the distraction phase.

Aliases: nerve pain

Neuropraxia

A temporary nerve-conduction block without axonal disruption; diagnosis and recovery require clinical assessment.

Non-union

Failure of a bone to heal within an expected time frame after fracture or osteotomy.

Aliases: nonunion

NSAIDs

A class of pain-relieving medications (e.g., ibuprofen) that may be restricted after limb lengthening.

Aliases: non-steroidal anti-inflammatory drugs

O

Osteolysis

Active resorption or dissolution of bone tissue.

Osteomyelitis

Infection of the bone tissue, a rare but serious complication in limb lengthening.

Aliases: bone infection

Osteotomy

A surgical cut of a bone to allow correction of deformity or enable limb lengthening.

P

Paley classification

A limb-lengthening adverse-event framework based on treatment course and whether a difficulty resolves.

Partial weight-bearing (PWB)

A weight-bearing status allowing only a fraction of body weight through the operated limb.

Aliases: PWB

Periosteal Reaction

New bone formation along the outer surface of existing bone, visible on X-ray, often a sign of irritation or stress.

Aliases: periostitis

Peroneal nerve

The nerve running down the outside of the knee and lower leg.

Physical therapy

A rehabilitation program using exercises, stretching, and manual techniques to restore strength and function after surgery.

Aliases: PT, physiotherapy

Pin-track infection

An infection at the site where a metal pin or wire of an external fixator enters the skin.

Aliases: pin-site infection

Plantarflexion

The movement of pointing the foot downward, away from the shin.

PRECICE

A specific brand of motorized intramedullary limb lengthening nail.

PRECICE MAX

A titanium magnetic lengthening system with a lot-specific U.S. recall record that must be checked for the exact device.

Aliases: Precice MAX

Prehabilitation

A structured exercise and conditioning program completed before surgery to improve post-operative recovery.

Aliases: prehab

Premature consolidation

A condition in which the bone gap closes before the target length is reached.

Aliases: premature union

Pulmonary embolism

A blood clot that travels to and blocks an artery in the lungs.

Aliases: PE

Q

Quadriceps

The large four-headed muscle group at the front of the thigh responsible for knee extension.

Aliases: quads

Quadrilateral

Refers to the four major long bones of the lower limbs: both femurs and both tibias.

Quadrilateral lengthening

Lengthening of both femurs and both tibias, either simultaneously or sequentially.

R

Re-osteotomy

A repeat surgical bone cut performed after a previous osteotomy.

Reaming

Widening of the intramedullary canal to prepare for nail insertion.

Regenerate

The new bone tissue that forms in the gap between two separating bone segments.

Aliases: regenerate bone

Remodeling phase

Gradual reshaping and strengthening of new bone over time after consolidation.

Retrograde

Nail insertion from the distal (lower) end of the bone, moving upward.

ROM (Range of Motion)

The extent of movement possible at a joint.

Aliases: range of motion

U

Urethral catheter

A thin tube inserted through the urethra into the bladder to drain urine.

Aliases: catheter, foley catheter

W

Weight-bearing

The act of supporting body weight through the limbs during standing or walking.

Aliases: WB

Wingspan

Distance between fingertips with arms fully extended; compared to height in proportion assessments.

Aliases: arm span

X

X-ray

A diagnostic imaging technique that uses electromagnetic radiation to produce images of bones.

Aliases: radiograph