Cruciate Injury and Arthrosis

In general, instability of the knee is not well tolerated and eventually post-traumatic arthritis develops. There is a significant amount of literature regarding ACL deficiency and post-traumatic arthritis. Some authors have reported the development of knee osteoarthritis (OA) after ACL injury in 50% of patients on average.^9,25 Others have reported the development of OA in up to 70% of patients with combined ACL and meniscal injuries at 15 to 20 years after injury.²⁰ Øiestad and colleagues,³² in a recent systematic review, indicated that the most accurate report of knee OA after isolated injury could be as low as 0% to 13%, and a prevalence of knee OA in combined ACL and meniscal injuries as high as 21% to 48%.

Patients with ACL and/or posterior cruciate ligament (PCL) deficiency, concomitant chondral and meniscal injuries, and preexisting malalignment of the knee are at increased risk of post-traumatic joint arthritis. In the case of ACL deficiency and underlying malalignment, with the loss of neuromuscular control, the knee is more likely to go into increased varus and overload the medial compartment. The varus knee with radiographic separation of the lateral tibiofemoral compartment and increased external rotation and hyperextension with an abnormal varus recurvatum position is referred to as a triple-varus knee.^6,31 Medial joint pain, instability, and early degenerative joint disease may result in patients with this clinical scenario.

The medial compartment tends to have a posterior medial tibial plateau wear pattern in triple- varus knees (Fig. 51-1). This is thought to be caused by a chronic anterior subluxation of the tibia with respect to the femur.⁵ This pattern is further exacerbated by medial meniscal insufficiency. As the degenerative process progresses and the arthritic changes occur, the knee becomes less unstable. The patient begins to have arthritis-type complaints rather than instability complaints.

Figure 51-1 AP (A) and lateral (B) views of a 50-year-old male chronic ACL-deficient patient with medial compartment OA, varus alignment, and no previous surgery. Note the medial wear on the AP view, and the posterior wear pattern on the lateral view caused by chronic anterior subluxation.

It is important to differentiate the cause of the patient’s complaints. The surgeon must determine whether he or she is suffering from underlying instability or if the complaints are caused by degenerative joint disease. The surgeon can differentiate between the two by determining which activities cause symptoms. It is important to distinguish whether the patient is complaining of pain with aggressive activities and pivoting types of movement, indicating instability, or of pain with activities of daily living, indicating arthrosis.

PCL-deficient knees are susceptible to posterior tibial subluxation and posterior instability.²⁷ Mavrodontidis and associates³⁰ have discussed two cases of rapid development of post-traumatic arthritis after failed PCL reconstruction. Instability of the knee joint leads to progressive knee arthritis. Much attention is devoted to soft tissue reconstruction, but surgeons may choose to ignore correctable risk factors for reconstruction failure such as joint malalignment. Frequently, joint malalignment contributes to the ligamentous injury prior to the discussion of reconstruction ever occurring. Geissler and Whipple¹⁶ found a 49% incidence of chondral defects and 36% incidence of meniscal tears in patients with chronic PCL instability. Keller and colleagues²² reviewed 40 PCL-deficient patients treated nonoperatively and found that 90% complained of knee pain with activity at 4 years from the time of injury, and only 12% of patients had normal-appearing radiographs. Clancy and associates⁸ found that 48% of patients with chronic PCL injuries had moderate to severe articular injury to the medial femoral condyle at the time of surgical reconstruction.

Posterior tibial slope and its relationship to instability in cruciate deficiency is also something to consider, particularly when considering osteotomy in these patients. Bonin and colleagues⁵ have described the relationship of pathologic tibial slope and incidence of ACL injury. The greater the slope, the greater the incidence of ACL instability. Giffin and associates,^18,19 Agneskirchner and coworkers,¹ and Dejour and Bonin¹² have shown that increasing tibial slope alters tibial translation, and this is augmented in the cruciate-deficient knee (Fig. 51-2).

Figure 51-2 Long lateral view of the tibia in a chronic ACL-deficient patient. Note the increased posterior slope and anterior subluxation of the proximal tibia.

Indications for Osteotomy

Osteotomies have been used for localized medial and lateral compartment gonarthrosis with varus and valgus malalignment. The principle supporting the use of tibial osteotomy is redistribution of the mechanical force across the joint. Coventry¹⁰ initially described the indications for high tibial osteotomy to include stable knees with no subluxation or thrust, range of motion (ROM) of at least 15 to 100 degrees, localized medial compartment OA, minimal or no patellofemoral symptoms, and age younger than 65 years. Indications for high tibial osteotomies have since expanded for cases of posterior instability, ACL deficiency, and correcting tibial slope in sagittal instability.^13,31 The senior author’s indications for osteotomy in the setting of instability are found in Box 51-1.

In the setting of ACL insufficiency with symptomatic instability and pathologic sagittal tibial slope, one should consider correction of the underlying malalignment issue in addition to ligamentous reconstruction. Previous observations of an increased incidence of ACL tears with increased tibial slope and biomechanical studies demonstrating increased anterior tibial translation with increasing tibial slope have suggested that decreasing the tibial slope would provide a more stable biomechanical environment.^12,18,19 The PCL-deficient knee presents a contrary situation in which decreasing tibial slope causes an increase in posterior tibial translation and symptoms of instability (Fig. 51-3).

Figure 51-3 A, Lateral view of the knee. Posterior instability of the knee and decreased posterior tibial slope accentuates posterior subluxation and hyperextension. B, Same patient treated with proximal tibial osteotomy to increase the slope and prevent hyperextension and posterior instability. Note the improved slope and decreased posterior subluxation. The tibial tubercle osteotomy was performed to move the tubercle proximally to prevent patella baja.

Treatment of Cruciate Deficiency and Arthrosis

If the patient is diagnosed with chronic ACL deficiency with early medial compartment arthritis and varus malalignment with overload, the physician should optimize conservative care, including unloader bracing, physical therapy, and activity modification. Patients who are experiencing arthritis-type symptoms related to previous meniscectomy, mechanical axis deviation into the medial compartment, and early medial compartment degenerative changes may benefit from a high tibial osteotomy (HTO). The painful symptoms from degenerative joint disease secondary to underlying instability and previous injury are termed pseudoinstability. In the setting of previously failed soft tissue reconstruction, one must consider malalignment as a contributing factor.

In the setting of a younger patient who is experiencing symptoms of instability with underlying malalignment and other meniscal or chondral pathology, the surgeon could consider ACL reconstruction in addition to an osteotomy. Surgeons are currently pushing the envelope for ACL reconstruction in older yet active patients with complaints of instability.

To determine whether an ACL reconstruction is indicated in addition to HTO, the physician must consider the patient’s complaints at the time of initial presentation. If an older or less active patient is suffering from mechanical overload and pain, they will likely respond to the osteotomy alone. It is important to assess the entire clinical picture and differentiate pseudoinstability from true instability. If the patient continues to complain of instability after HTO, ACL reconstruction can be considered as a secondary procedure. However, ACL reconstruction alone in the face of malalignment is doomed for continuing symptoms of compartment overload and early failure of the ACL surgery.

Preoperative Evaluation

Factors considered in the preoperative evaluation and prior to indication for osteotomy include the following: (1) pure valgus or varus malalignment; (2) loss of neuromuscular control associated with ligament injury and loss of proprioceptive feedback (thrust during stance); (3) abnormal sagittal slope in the setting of ACL or PCL insufficiency; (4) triple-varus knee; and (5) unicompartmental degeneration (usually a postmeniscectomy knee).

The preoperative examination should include a detailed history, clinical examination, and imaging studies. Physical examination findings supportive of an osteotomy include joint line tenderness, abnormal gait patterns, with special attention to lateral thrust, and limb alignment in stance. Attention is directed toward instability tests including Lachman, pivot shift, anterior and posterior drawer, reverse pivot shift, and external rotation tests. The examiner should note the double- or triple-varus knee associated with ACL, PCL, or posterolateral corner deficiency.

Radiographic evaluation begins with assessment of the extent of knee arthrosis and lower extremity alignment with bilateral standard weight-bearing long-leg (hip to ankle) anteroposterior views, standard anteroposterior views in full extension, bilateral weight-bearing posteroanterior tunnel views in 30 degrees of flexion, and lateral and Merchant patellar views. Dugdale and coworkers¹⁴ have described the technique used to calculate the HTO correction. The mechanical axis and weight-bearing axis are determined and the correction to be made is calculated just lateral to the lateral tibial spine (Fig. 51-4).

Figure 51-4 A, Hip to ankle x-ray (the patient is standing with equal weight on both legs) to measure preoperative varus deformity. B, Postoperative correction of varus deformity with medial opening wedge osteotomy.

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Management of Extra-articular Deformity in Total Knee Arthroplasty With Navigation Patellar Instability Posterior Cruciate Ligament Reconstruction: Posterior Inlay Technique Perioperative Management of the Patient With Coronary Stents Osteochondritis Dissecans Anatomic Aberrations

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