CLINICAL CONCEPTS

The protocol described in this chapter was designed for opening wedge high tibial osteotomy (HTO) and distal femoral osteotomy (DFO) in which an autogenous iliac crest bone graft is used along with internal fixation with a locking plate and screw. The operative techniques, detailed in Chapter 31, Primary, Double, and Triple Varus Knee Syndromes: Diagnosis, Osteotomy Techniques, and Clinical Outcomes, prevent delayed union or nonunion and collapse at the osteotomy site and allow a rehabilitation program of immediate knee motion and early weight-bearing, preventing the complications of arthrofibrosis and patella infera.¹^–⁵ As discussed in Chapter 31, allograft instead of an iliac crest autograft is frequently used for open wedge osteotomy. In these knees, a more cautious approach is required for resuming weight-bearing because healing is delayed approximately twofold. Full weight-bearing is not allowed until the surgeon advises based on radiographic evidence of healing. In addition, the physical therapist is informed whether a locking plate and screw fixation was used because this provides more rigid fixation. If a smaller non–locking plate and screw was used, protection from weight-bearing is required until osteotomy healing is advanced. In rare cases in which the opening wedge has been compromised at the lateral tibial cortex, inducing a fracture, no weight-bearing is allowed until complete healing of the osteotomy is verified.

Patients receive instructions before surgery regarding the postoperative protocol so they have a thorough understanding of what is expected after the procedure. The supervised rehabilitation program is supplemented with home exercises that are performed daily. The therapist routinely examines the patient in the clinic postoperatively in order to progress the patient through the protocol in a safe and effective manner. Therapeutic procedures and modalities are used as required to achieve a successful outcome.

The overall goals of the osteotomy and rehabilitation are to control joint pain, swelling, and hemarthrosis; regain normal knee flexion and extension; resume a normal gait pattern and neuromuscular stability for ambulation; regain lower extremity muscle strength, proprioception, balance, and coordination for desired activities; and achieve the optimal functional outcome based on orthopaedic and patient goals.

Critical Points CLINICAL CONCEPTS

• Protocol designed for opening wedge high tibial osteotomy and distal femoral osteotomy

Autogenous iliac crest bone graft, internal fixation with locking plate and screw.

Allograft bone graft, delayed weight-bearing until radiographic evidence healing.

• Immediate knee motion, early weight-bearing prevent arthrofibrosis and patella infera.

• Preoperative patient education essential.

• Program is supervised, patient performs exercises at home daily.

Immediately after surgery, the lower limb is wrapped with cotton with additional padding placed posteriorly, followed by a double compression and cotton bandage, postoperative hinged brace, and bilateral ankle-foot compression boots. A commercial ice delivery system is used with the bladder incorporated over the initial cotton wrapping, a few layers from the wound. The neurovascular status is checked immediately in the operating room and carefully monitored in the initial postoperative period. A calf or foot compression system is used for the first 24 hours to promote venous blood flow. Aspirin is prescribed and, rarely in high-risk patients, low-molecular-weight heparin (LMWH) or warfarinsodium (Coumadin; Bristol-Myers Squibb Co., Plainsboro, NJ). During the 1st postoperative week, patients are ambulatory for short periods of time, but are instructed to elevate their limb, remain home, and not resume usual activities.

Prophylaxis for deep venous thrombosis (DVT) includes intermittent compression foot boots in both extremities, immediate knee motion exercises, antiembolism stockings, ankle pumps performed hourly, and aspirin (600 mg/day for 10 days). Doppler ultrasound is obtained if a patient demonstrates abnormal calf tenderness, a positive Homans sign, or increased edema.

Important postoperative signs to monitor include (Table 33-1):

Loss of correction, reoccurrence of varus or valgus malalignment.

Delayed union or nonunion.

Swelling of the knee joint or soft tissues.

Abnormal pain response, increased pain with weight-bearing.

Abnormal gait pattern.

Insufficient flexion or extension, limited patellar mobility.

Weakness (strength/control) of the lower extremity.

Insufficient lower extremity flexibility.

Peroneal nerve palsy.

DVT (calf pain, Homans’, tibial edema).

TABLE 33-1 Postoperative Signs and Symptoms Requiring Prompt Treatment

Postoperative Sign, Symptom	Treatment Recommendations
Failure to meet knee extension and flexion goals (see text)	Overpressure program, early gentle manipulation under anesthesia if 0°–135° not met by 6 wk postoperatively.
Decreased patellar mobility (indicative of early arthrofibrosis)	Aggressive knee flexion, extension overpressure program, or gentle manipulation under anesthesia to regain full knee ROM and normal patellar mobility.
Decrease in voluntary quadriceps contraction and muscle tone, advancing muscle atrophy	Aggressive quadriceps muscle–strengthening program, EMS.
Persistent joint effusion, joint inflammation	Aspiration, rule out infection, close physician observation.
Loss of angular correction	Immediate referral to physician for revision.
DVT: abnormal calf tenderness, a positive Homans sign, or increased edema	Immediate ultrasound evaluation.

DVT, deep venous thrombosis; EMS, electrical muscle stimulation; ROM, range of motion.

POSTOPERATIVE REHABILITATION PROTOCOL

Modalities

The postoperative rehabilitation protocol after tibial and femoral osteotomy is summarized in Table 33-2. In the immediate postoperative period, knee pain and effusion must be controlled to avoid quadriceps muscle inhibition or shutdown. Electrogalvanic stimulation or high-voltage electrical muscle stimulation (EMS) may be used to augment ice, compression, and elevation to control swelling. The treatment duration is approximately 30 minutes and the intensity is set to patient tolerance.

TABLE 33-2 Rehabilitation after High Tibial or Femoral Osteotomy