Uploaded byAsish Rajak
General principles of Plaster of Paris cast/slab immobilization in fracture management
This presentation provides a detailed and practical overview of Plaster of Paris (POP) application in orthopedic practice, covering its history, indications, principles, techniques, complications, and essential postoperative care. Designed for trainees and clinicians involved in trauma and orthopaedic care, it outlines both the theoretical foundations and hands-on principles necessary for safe and effective cast and slab application. The presentation begins with the origin of Plaster of Paris, highlighting its composition as gypsum plaster and its medical introduction by Antonius Matthysen in 1852, later becoming commercially available in 1931. This offers context for understanding why POP remains widely used even today. A comprehensive section on the uses of POP bandage follows, divided into trauma and non-trauma indications. In trauma, POP is used to immobilize fractured bones, protect ligament injuries, and rest soft tissues after contusions. It also provides support after tendon, nerve, and vascular repairs. Non-traumatic uses include deformity correction such as in the Ponseti technique for clubfoot, preventing deformities like equinus in foot drop, infection-related immobilization, and orthotic/prosthetic moulding. The presentation stresses the importance of a thorough initial clinical assessment, including inspection for open fractures, vascular injury, nerve damage, and associated visceral trauma. Proper diagnosis and limb evaluation are crucial before any immobilization. The technical principles of plaster preparation are described in detail, including the chemical reaction of hydrated gypsum, ideal water temperature, setting time (3–9 minutes), drying time (24–72 hours), weight-bearing protocols, and factors that accelerate or delay setting. Key principles of cast application are explained: immobilizing one joint above and below the injury, positioning joints functionally, ensuring adequate padding, and allowing movement of joints not included in the cast. Guidelines cover stockinette use, padding of bony prominences, avoiding wrinkles, proper molding using palms instead of fingertips, and preventing thermal injury from excessive layers or hot water. The presentation then covers the three major types of POP casts—badly padded, unpadded, and padded—and discusses their advantages and limitations. Unpadded casts, historically used by Böhler, provide excellent fixation but require high expertise. Padded casts are most widely used today; the talk includes detailed instructions on the correct technique, emphasizing even pressure distribution, smooth layering, careful cotton preparation, and progressive forward–backward rhythm during application. Common errors in padded plaster application are identified, such as holding reduction during plastering, careless padding, loose bandaging, the "Wellington boot effect," and failure to assess reduction quality after application.
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General principles of Plaster of Paris cast/slab immobilization in fracture management
- 1. General principles of Plasterof Paris cast/slab immobilization in fracture management Dr Asish Rajak JR Department of Orthopaedics BPKIHS, Dharan
- 2. PLASTER OF PARIS Gypsum Plaster- Dehydrated gypsum Antonius Matthysen (1805-1878) a Dutch military surgeon in 1852 was the first to make use of POP for medical purposes. POP became commercially available since 1931.
- 3. USES OF POPBANDAGE TRAUMA BONY INJURY: To immobilize the fractured bone LIGAMENT INJURY: To immobilize the joint till healing occurs. SOFT TISSUE INJURY: In case of severe contusion of skin and muscles, giving rest to the affected part improves healing. AFTER TENDON, NERVE, VESSEL REPAIR.
- 4. NON-TRAUMA DEFORMITYCORRECTION : For example correction of clubfoot by serial cast application ( Ponseti technique) DEFORMITY PREVENTION: For example In case of foot drop a Below-Knee slab is applied at 90° to prevent equinus. INFECTION: To give rest to the affected part. Improves healing. IN ORTHOTICS AND PROSTHETICS: To take a negative mould of the limb as a first step in making of artificial limb.
- 5. APPROACH The initial approachto casting and splinting requires a thorough assessment of the skin, neurovascular status, soft tissues, and bony structures to accurately assess and diagnose the injury.
- 6. CLINICAL Assessment Excludeinjuries to other systems before examination of the skeletal injury. Examination of the limb should determine: 1. whether there is a wound communicating with the fracture? 2. whether there is evidence of a vascular injury? 3. whether there is evidence of a nerve injury? 4. whether there is evidence of visceral injury?
- 7. Technique of Plasterapplication 2 (CaSO4 ½ H2O) + 3 H2O→ 2 (CaSO4 . 2H2O) + Heat the bandage is soaked till no more bubbles come up TEMPERATURE OF WATER: 25 to30˚C WEIGHT-BEARING ALLOWED AFTER: 48 hours RELATIVELY RADIO OPAQUE SHELF LIFE: 2 to 3 years
- 8. Setting time:time taken to change from powder form to crystalline form. Average setting time: 3-9 minutes. Drying time: time taken to change from crystalline form to anhydrous form. Average drying time: 24-72 hours
- 9. Factors That AffectSetting Times Factors that speed setting times 1. Higher temperature of dipping water 2. Use of fiberglass 3. Reuse of dipping water Factors that slow setting times 1. Cooler temperature of dipping water
- 10. Principles of plasterapplication Immobilize one joint above and one joint below the affected part. Immobilize a joint in its functional position. Adequate padding of pressure areas. Mobilization of the joints not incorporated in the cast.
- 11. Guidelines for ProperCast Appropriate amount and type of padding Properly pad bony prominences and high pressure areas Properly position the extremity before, during, and after application of materials Avoid tension and wrinkles on padding, plaster, and fiberglass
- 12. Use palms/flatof hand to mold Avoid fingertips Creates indents and cast sores Avoid burns Hotter water and more layers cast material = HEAT as cast sets up Be careful with young, elderly. Avoid excessive molding and indentations Wrap distal to proximal Turn stockinette back for padded edge
- 13. Plaster Technique Plaster castscan be divided into 3 types: 1) Badly padded plaster 2) Unpadded plaster 3) Padded plaster
- 14. Badly padded plaster It is loose on the limb and therefore cannot fix the fragments.
- 15. Unpadded Plaster Madeby applying the turns of wet bandage directly to the skin without using any textile. (used by Böhler) For practical purposes, if stockinet is used the resulting plaster can still be regarded as an unpadded cast. The closeness of its application to the limb and actual adhesion to the skin, is believed to enhance fixation of a fracture.
- 16. Considerably easierto learn than padded plaster technique Bandage should never be pulled tight Bandage should be made to roll itself round the limb. Should be applied by laying the wet roll of plaster on the skin and pushing it round the curves of limb with flat of hand. The roll of plaster should not be lifted off the limb and pulled. Recommonded in 3 condition by sir Charnley: 1) Colles’ fracture 2) scaphoid fracture 3) Bennett’s fracture
- 17. Padded plaster cast A layer of cotton-wool is interposed between the skin and plaster, which is firmly compressed against the limb by applying wet plaster bandage under tension. The elastic pressure of the cotton enhances the fixation of limb by compensating for shrinkage in tissues . When expertly applied, these plasters grip the limb more firmly and keep this grip for longer time than unpadded one. The care with which cotton is applied is essential for success. It must not obscure the shape of limb by being put on in careless and ugly lumps. The cotton if not rolled already, should be carefully prepared in rolls before application.
- 18. The rollof bandage remains in contact with surface of limb almost continuously. Bandage is pressed and pushed round the limb by the pressure of thenar eminence under a strong pushing force directed in length of surgeon’s forearm. Pressure is applied at the middle of width of bandage so that no excess of pressure can fall on either edge . At tapering parts of the limb, the turns are made to lie evenly by small tucks which are made with quick movement of index finger of left hand. The durability of the cast depend on welding together of individual turns by smoothing movements of left hand. Each layer must be applied with equal deliberation.
- 19. The hall-markof good plaster is that it should be of even thickness from end to end. Never apply two turns in the same place except at the ends. Have a progressive ‘backward and forward rhythm’ from top to bottom.
- 20. PADDING This isplaced from distal to proximal with a 50% overlap, a minimum two layers, and extrapadding at the fibular head, malleoli, patella, andolecranon.Extra padding is placed at areas of bony prominence. If significant swelling is anticipated, more padding may be used
- 21. A layer ofstockinet forms a comfortable lining which prevents the plaster from sticking to the hairs. The hand is shown in a position of function, with slight dorsiflexion at the wrist and the thumb opposed.
- 22. The end isunwind for a few centimetres so that it will be found easily when the bandage is wet. The wet bandage is squeezed lightly from the ends but is not wrung out.
- 23. • In upperextremity casts – follow palmar crease for hand function – Appose thumb + index • In lower extremity casts – Don’t get too high into popiteal fossa short leg – Consider great and little toes • 8 inch for thigh,6 inch for leg and 4 inch for forearm
- 24. Errors in applyingPadded Plasters 1. Attempting to plaster at the same time as attempting to hold a precise reduction. 2. Applying wool carelessly in shapeless lumps 3. Loose bandaging 4. Wellington boot effect 5. Failing to recognise sensation of reduction through the plaster
- 25. ADVICE GIVEN AFTER PLASTERAPPLICATION keep the limb elevated Active or passive mobilization of fingers toes Report to ER immediately if there is Excessive pain, Increased swelling Altered color ( bluish, white )of the digits Numbness, tingling, pins and needles sensation in the limb Unconsolable cry in case of child Foul smell from the cast, discharge, blood coming out from the cast. The period of greatest danger is between 12 and 36 hours after the injury or operation. Next OPD visit <24hrs.
- 26. Complications of POP Due to tight cast – 1 pain -pressure sores -compartment syndromes -peripheral nerve injuries 2 c/o unrelenting pain,stretch pain, swelling over fingers, inability to move fingers, hypoaesthesia and bluish discolouration of the digits.
- 27. Due toimproper application- joint stiffness, plaster blisters, sores, breakage Due to plaster allergy -allergic dermatitis
- 28. CAST COMPLICATIONS CastBreakdown Under heel – too much padding or not enough material Can crack at junction rolls if rolls not taken full length of cast Cast malposition • Loosening – If limb swollen when applied, will often need to change 3-7 days later • Wet/Damp cast – From bathing – From sweat
- 29. Functional brace (castbrace) suitable for certain fractures of the femoral shaft or tibia. Note the plastic hinges incorporated at the knee. Hinges may also be fitted at the ankle.
- 30.
- 31. MOULDING Making theplaster fit into the contour of the limb by manual pressure applied with the base of the hand ( not with the fingertips ).
- 32. THREE-POINT-MOULDING After closedreduction the fracture has a tendency to get re displaced as it was before. This is prevented most effectively by molding the cast at three places: at the fracture site, proximal to it and distal to it.
- 33. SLAB-CAST-SPICA-BRACE SLAB: multiplelayers of POP bandage stacked into one and applied longitudinally along a part of the circumference of the limb with a wet cotton bandage. 14 to16 layers in UL, 16 to 18 layers in LL. CAST: encircles the whole circumference of the limb.
- 34. SPICA: whena limb is immobilized along with a part of the trunk. Hip spica in shaft of femur fracture in children. BRACE is an appliance used to support a weak part of body or to prevent or correct a deformity.
- 35. WINDOW MAKING Ifthere is a wound in the limb which requires frequent inspection and dressing the area of the wound is marked on the cast at the time of application. The next day when the cast has set, the marked area is cut open.
- 36. PLASTER CUTTING The lineof cut should be over soft tissues and concavities and should avoid the bony prominences
- 37. • Cast sawvibrates • Can CUT skin if dragged • Support saw with hand • Go down throughout the material then come back up and move in direction of cut out of cast – go back down
- 38. Oscillation rather than rotationof the blade guards against its damaging the skin cut down through the plaster in multiple sections each equal to the diameter of the blade, rather than to slide the oscillating blade along the plaster - Patient : noisy, frightening, unpleasant amount of dust.
- 39. • Use spreaderto separate cast • Use scissors to cut around top and bottom of top shell to remove • Cut longitudinal through stockinette/padding.
- 40. WEDGING This iscutting circumferentially ( keeping one-fourth of the circumference intact ) of the cast to correct residual angulation after the cast application. This is done after 48 hours and upto 2 weeks. It can be done in 2 ways Open wedge: on the concave side (there is slight gain in length.) Close wedge: on the convex side (there is slight loss of length.)
- 41. IDEAL CASTING MATERIAL Suitable for direct application to the patient Non-toxic to the patient and to the user Easy to mould Quick setting Strong Light weight Able to transmit air, odour, water, pus
- 42. Easy tomodify Easy to remove Transparent to the x-rays Long shelf-life Cheap Non-messy in application and removal Unaffected by fluid, water Non inflammable
- 43. REFERENCES John Charnley,The Closed Treatment of Common Fractures, 4th edition STEWART,HALLETT: Traction and Orthopaedic appliances, Second edition MAHESHWARI: Essential Orthopedics,Third edition
- 44.
Editor's Notes
- #2 this dehydrated gypsum became known as plaster of Paris. Upon addition of water, after a few tens of minutes plaster of Paris becomes regular gypsum (dihydrate) again, causing the material to harden or "set" in ways that are useful for casting and construction. plaster of Paris, is produced by heating gypsum to about 300 °F (150 °C) Fig. Fibrous gypsum selenite showing its translucent property.
- #7 - calcium sulphate hemihydrate to calcium sulphate dihydrate - Chemical reaction that occurs when a POP Bandage is soaked in water ( till it sets hard ) - High temperature and addition of salt make it set faster.
- #25 - keep the limb elevated: edema↓,assist venous return. - Active or passive mobilization of fingers toes: controls edema, prevents stiffness.
- #30 - While traversing a joint ( especially the elbow joint while applying an A/E cast or slab) the bandage is bridged at a distance from the joint from the arm to the forearm so that direct pressure on the cubital fossa from the subsequent layers is prevented.
- #32 - (The inner surface of the cast at the molded areas have a firm contact with the limb. Other parts of the cast might not have that much fit as the cast becomes loose after a few days when the edema subsides.)
- #36 - When the decision is made to remove the plaster it is unwise to do so if the patient is not by this time already capable of good function in the plaster . - In hand midline of the anterior surface,crossing the wrist in the hollow between the tuberosity of the scaphoid bone and the pisiform bone. Only one cut is required, because the plaster is thin enough to be opened out without difficulty when it has been cut through. - In the leg plaster two cuts should be made. The first cut should be made along the lateral surface and should pass in front of the lateral malleolus,. The second cut should be made along a corresponding line at the medial side of the plaster, passing behind the medial malleolus.