Soft Dressing vs. Rigid Dressing vs. Rigid with Immediate Prosthesis?
ï¿½ Soft Dressing
For many years, the standard practice – sterile soft dressings with compressive bandaging to control post-op edema and bleeding; periodic wound inspection & adjustment of bandages
Advantage: early detection of infection and/or wound breakdown.
Disadvantages: variable pressure along stump, virtually inevitable proximal constriction causing terminal edema, pain from movement, flexion contracture from reflex muscle spasm, and increased risk of causing the actual infection!
ï¿½ Semi-Rigid or Rigid Dressings
The new standard of practice – wide variety of choices: metal, fiberglass, plaster, Unna paste. Dressing left on for 5-10 days.
Advantages: avoids proximal constriction, provides terminal wound support and thus comfort for mobilization, prohibits the early development of flexion contracture.
Disadvantages: must be properly suspended otherwise the terminal pressure will be lost and the stump allowed to swell. Does not allow for wound visualization.
POSTOPERATIVE STUMP MANAGEMENT (contï¿½)
ï¿½ Rigid Dressing with Immediate Post-Surgical Prosthesis Fitting
Technique developed in the 1960’s – rigid plaster cast molded to a patella-tendon-bearing configuration to which a pylon and foot are attached. Touch weight-bearing is started within 24-48 hours after surgery.
Advantage: early mobilization and adaptation.
Disadvantages: risk of wound breakdown and undue wound stress. Patients require good strength, balance, proprioception, and cognition to avoid putting excessive amounts of weight on the stump too soon. Need highly trained personnel and good facilities.
ï¿½ Mooney et al. (1971, J. Bone Joint Surg): Randomized 182 BKA patients to soft, rigid, and rigid with immediate prosthesis fitting. Greatest delay in ultimate prosthetic fitting with soft dressings. Faster healing with rigid dressing than rigid with immediate prosthesis fitting.
ï¿½ Barber et al. (1983, Can. J. Surg): Randomized 70 BKA patients to soft vs rigid dressings. Rigid dressings provided less pain, improved patient confidence, earlier prosthetic fitting.
Conclusion. Soft dressings are obsolete. Immediate prosthesis fitting is theoretically ideal, but impractical in a center doing relatively few cases, (but nonetheless may have a role in certain individuals). Rigid/semi-rigid dressings are in general the dressings of choice.
ï¿½ The primary goal is to produce a prosthesis which permits virtually unhindered function of the knee on the amputated side. This is virtually always accomplished using a patellar-tendon-bearing prosthesis of one design or another.
ï¿½ A longer stump will provide a larger surface area for achieving stability between the stump and socket for weight support. However, at the musculo-tendinous junction of gastrocnemius, the soft tissue coverage diminishes and the stump is often over-sensitive.
ï¿½ The biomechanical advantage conferred by a longer stump is undeniable. With current technology, a reasonable prosthesis can be fashioned for a stump cut even as high as the tibial tubercle.
ï¿½ Socket: A total contact socket in which the largest possible area of stump shares in the distribution of weight is optimum for support and control of the forces generated between the stump and socket during gait. Most commonly, a hard socket (fiberglass) with a molder layer of padding.
ï¿½ Suspension: Number of different methods of supporting the prosthesis – supracondylar suspension, supracondylar strap, silicone sleeve, suction. Suspension becomes increasingly important as the stump gets shorter.
ï¿½ Foot: Depending on the amount of torque that the amputee is able to generate, the foot component of the prosthesis can be made rigid (Solid Ankle Cushion Heel – SACH), single-axial, multi-axial.
INDICATIONS (Haimovici, 1996)
Generally restricted to those cases in which a BKA isÂ contraindicated
ï¿½ Extensive gangrene and infection extending above the ankle.
ï¿½ Associated painful flexion contracture of the knee joint.
ï¿½ Recent acute occlusion of the femoral or iliac artery.