Medial and posteromedial instability of the knee: evaluation, treatment, and results

Medial-sided knee ligament injuries are complex and require a thorough understanding of the anatomy and the scope of injury to successfully treat. Patients with isolated medical collateral ligament (MCL) tears can normally be treated with bracing followed by physical therapy with outstanding results. Patients with isolated Grade III injuries to the MCL are controversial. A reason for the disparity in results reported may be due to the fact that many (if not most) Grade III MCL tears have associated injuries to the anterior cruciate ligament and/or posteromedial corner injury. Patients with combination injuries should be treated surgically with repair or reconstruction in most cases. Either allograft or autograft reconstructions of both the MCL and posteromedial corner can be successful. Successful elimination of anteromedial rotary instability is the key to successfully treating posteromedial corner injuries.     

Posterolateral corner injuries of the knee: anatomy, diagnosis, and treatment

Injuries to the posterolateral corner of the knee continue to be a complex problem for orthopedic surgeons. Early recognition and treatment are important factors in the patient's long-term outcome. To properly treat these patients, the surgeon must have a clear understanding of the anatomic relationships amongst the structures in the posterolateral knee. This knowledge combined with a thorough physical examination and imaging studies, allows the surgeon to make the correct diagnosis and devise an appropriate treatment plan. This article will discuss the anatomy, diagnosis, and treatment options to improve the surgeon's understanding of posterolateral knee injuries. The senior author's technique for anatomic reconstruction of the posterolateral corner of the knee and the rehabilitation protocol are described.     

Posterolateral instability of theknee: treatment using the clancy biceps femoris tenodesis

Posterolateral instability of the knee is perhaps the most challenging injury facing the sports medicine physiciantoday. Diagnosis requires a thorough understanding of the complex anatomy, function, and biomechanics of the posterolateral structures. In isolated cases of posterolateral instability, the physical findings may be subtle and easily overlooked. Similarly, in complex injuries involving the posterolateral structures, the physical findings may be confusing and misdiagnosed as an isolated cruciate ligament injury. Failure to appropriately diagnose and treat a posterolateral injury can lead to significant functional disability and failure of associated ligamentous reconstruction. Optimal results may be achieved if the injury is diagnosed acutely and surgical treatment is carried out promptly with stabilization of the posterolateral structures and any associated ligamentous insufficiencies. The clinical and biomechanical results of the Clancy biceps tenodesis have proven the procedure successful for controlling varus and external rotational laxity. Rerouting of the biceps femoris tendon with tenodesis to the lateral femoral epicondyle creates a new fibular collateral ligament and tightens the posterolateral capsule and arcuate complex. In addition, tenodesis eliminates the dynamic external rotation of the tibia by the biceps femoris muscle, which actively exacerbates posterolateral subluxation. When performed properly, the biceps tenodesis can eliminate posterolateral instability and restore functional stability to the knee.     

High tibial osteotomy in knee instability: the rationale of treatment and early results

We treated 14 patients having knee instability and varus alignment with tibial osteotomy with or without ligament reconstruction. Five patients with varus angulated anterior cruciate deficiency (double varus) were treated with single-stage closed-wedge tibial osteotomy and anterior cruciate ligament reconstruction. The remaining nine patients had varying amount of posterior cruciate and postero-lateral corner ligament injuries with varus angulation (triple varus); six of these patients had a ligament reconstruction using the Ligament Advanced Reconstruction System ligament with tibial osteotomy (intra-articular--posterior cruciate ligament/extra-articular--postero-lateral corner reconstruction), while the remaining three had a tibial osteotomy without a ligament reconstruction. Four of the nine patients with triple varus had open-wedge tibial osteotomy, and the remaining five had closed-wedge tibial osteotomy. The mean time interval between injury and index surgery of an osteotomy and ligament surgery was 8.3 years (range 1-20 years). At a mean follow-up of 2.8 years after tibial osteotomy, 12 knees (86%) were stable and eliminated of giving way while the remaining 2 were unstable. In one of these patients the result was compromised with severe infection, while in another there was combined cruciate ligament deficiency with postero-lateral corner ligament deficiency. Thirteen (93%) of the patients were able to participate in light recreational activities. None of these patients could return to competitive sports. Five (35%) continued to have pain of varying degree. The mean Cincinnati Knee Score improved from a mean preoperative of 53 (range 40-58) to a mean postoperative of 74 (range 58-82). Accordingly, there were two poor, four fair and eight good results. In-patients with triple-varus, open-wedge tibial osteotomy had better scores than those with closed-wedge procedure. The results of this series are encouraging, and we recommend a high tibial osteotomy along with ligament reconstruction in these complex injuries with varus alignment.     

Posterolateral aspect and stability of the knee joint. II. Posterolateral instability and effect of isolated and combined posterolateral reconstruction on knee stability: a biomechanical study

This study evaluated the correlation between the number of transected posterolateral structures (PLS) and the grade of posterolateral rotational instability, determined the effect of the popliteus muscle-tendon unit on the tibial rotation, and examined the effect of an isolated posterior cruciate ligament (PCL) and combined PCL-PLS reconstruction on knee stability. Sectioning the popliteofibular and lateral collateral ligaments both caused an increase in tibial external rotation. Cutting the PT resulted in a statistically highly significant excessive external rotation and externally shifted neutral position of the tibia over the full range of motion. Tensioning the popliteus muscle-tendon unit led to a statistically highly significant internally shifted neutral tibial rotation and a decreased internal and an increased external rotation without affecting the total rotational arcs. The isolated PCL reconstruction did not affect the external rotation, whereas the combined PCL-PLS reconstruction reset the knee to nearly physiological laxity patterns.     

Operative treatment of posterolateral knee instability

Recognition of posterolateral rotatory instability (PLRI) and identification of the anatomic structures of theposterolateral region of the knee and their contribution to stability has occurred recently; therefore, surgical techniques to address these problems are evolving.     

Chronic anterolateral instability of the knee. A roentgen stereophotogrammetric evaluation

The rotatory stability of the knee was investigated in 20 patients with a previous tear of the ACL. The three-dimensional movements of the tibia during the testing procedure were registered using roentgen stereophotogrammetric analysis. Changes of the tibial movements between an intermediate, an anterior, or a posterior tibial position were registered using tibial tractions in combination with a simultaneous external or internal rotatory torque. At 20 degrees of flexion the internal rotatory laxity was increased on the injured side. The external rotatory laxity did not significantly differ between the two sides. With anterior traction, the internal rotatory laxity increased on both the injured and the normal sides and became almost equal. The external rotatory laxity manifested a decrease which was most pronounced on the injured side. With posterior traction, the rotatory laxities decreased and did not significantly differ between the two sides. Analysis of the simultaneously occurring translations of the tibial plateau disclosed abnormal displacements of both the medial and the lateral tibial condyles on the injured side.     

MR evaluation of the "arcuate" sign of posterolateral knee instability

OBJECTIVE: The purpose of this study was to evaluate associated knee injuries using MR imaging in patients with the "arcuate" sign, a term referring to avulsion fracture of the proximal fibula on conventional radiographs. MATERIAL AND METHODS: MR imaging of 18 cases (17 patients, both knees in one patient) with the arcuate sign on conventional radiographs was retrospectively interpreted to evaluate the associated meniscal, ligamentous, and bony injuries. In 12 cases, MR findings were correlated with surgical results. RESULTS: In all cases, avulsed bony fragments from the proximal pole of the fibula were attached to the fibular collateral ligament, the biceps femoris tendon, or both. Tear of the posterolateral capsule was seen in 12 cases (67%). Injury of the cruciate ligaments was noted in 16 cases (89%): injury to both the anterior cruciate ligament and posterior cruciate ligament was seen in nine cases (50%), injury to only the anterior cruciate ligament was seen in four, and injury to the posterior cruciate ligament only was noted in three. Bone bruises or gross fractures were seen in all cases: bone bruises on the anteromedial femoral condyle were noted in nine cases (50%) and were seen on the anteromedial tibial condyle in five cases (28%). Tear of the medial meniscus was seen in five cases (28%) and tear of the lateral meniscus in four cases (22%). Injury to the popliteus was seen in six cases (33%). Joint effusion was associated in all cases. CONCLUSION: MR imaging is useful for evaluation of associated soft-tissue injuries in patients with the arcuate sign on conventional radiographs. Avulsion injury to the proximal fibula is an important indicator of the internal derangement of the knee and for predicting the mechanism of an injury with varus stress. Cruciate ligament tear and bone bruises on the anteromedial condyle of the femur and tibia are common associated findings.     

Posterolateral supporting structures of the knee: findings on anatomic dissection, anatomic slices and MR images

In this article we study the ligaments and tendons of the posterolateral corner of the knee by anatomic dissection, MR-anatomic correlation, and MR imaging. The posterolateral aspect of two fresh cadaveric knee specimens was dissected. The MR-anatomic correlation was performed in three other specimens. The MR images of 122 patients were reviewed and assessed for the visualization of different posterolateral structures. Anatomic dissection and MR-anatomic correlation demonstrated the lateral collateral, fabellofibular, and arcuate ligaments, as well as the biceps and popliteus tendons. On MR images of patients the lateral collateral ligament was depicted in all cases. The fabellofibular, arcuate, and popliteofibular ligaments were visualized in 33, 25, and 38% of patients, respectively. Magnetic resonance imaging allows a detailed appreciation of the posterolateral corner of the knee.     

Posterolateral complex knee injuries: magnetic resonance imaging with surgical correlation

Purpose: To describe the magnetic resonance imaging (MRI) findings of injuries of the posterolateral aspect of the knee and to evaluate the diagnostic capabilities of MRI in the assessment of these injuries.

Material and Methods: The MRI studies of 14 patients (mean age 33 years) with trauma to the posterolateral aspect of the knee were retrospectively reviewed, and the imaging findings were correlated with those of surgery.

Results: In all patients, MRI showed an intact iliotibial (ITB) band. MRI showed injury to the biceps tendon in 11 (79%), the gastrocnemius tendon in 1 (7%), the popliteus tendon in 5 (36%), and the lateral collateral ligament (LCL) in 14 (100%) patients. Tear of the anterior cruciate ligament (ACL) was seen in 11 (79%) patients and tear of the posterior cruciate ligament (PCL) in 4 (29%) patients. With routine MRI, visualization of the popliteofibular or fabellofibular ligaments was incomplete. On MRI, the lateral meniscus and the medial meniscus were torn with equal frequency (n = 4; 29%). Osteochondral defects were seen in 5 (36%) cases and joint effusion in all 14 (100%) cases on MRI. Using surgical findings as the standard for diagnosis, MRI proved 86% accurate in the detection of injury to the ITB band, the biceps tendon (93%),, the gastrocnemius tendon (100%), the popliteus tendon (86%), the LCL (100%), the ACL (79%), the PCL (86%), the lateral meniscus (90%), the medial meniscus (82%), and the osteochondral structures (79%). Surgical correlation confirmed the MRI findings of joint effusion in all cases.

Conclusion: MRI is well suited for demonstrating the presence and extent of injuries of the major structures of the posterolateral complex of the knee, allowing characterization of the severity of injury.     

Arthroscopic treatment of posterior shoulder instability: results in 33 patients

BACKGROUND: Posterior shoulder instability is a relatively rare condition and a surgical challenge. Arthroscopic techniques have allowed for a potential improvement as well as diagnosis and management of this condition. PURPOSE: To evaluate the outcomes of arthroscopic posterior shoulder stabilization and to evaluate preoperative and intraoperative variables as predictors of success. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty-three consecutive patients with a mean age of 25 years (range, 19-34 years) who underwent posterior arthroscopic shoulder stabilization with suture anchors (mean, 3 anchors) or suture capsulolabral plication (mean, 5.3 stitches) or both were reviewed at a mean follow-up of 39.1 months (range, 22-60 months). Shoulder outcomes rating scores were determined using the American Shoulder and Elbow Surgeons Rating Scale, the Western Ontario Shoulder Instability Index, the Subjective Patient Shoulder Evaluation, and the Single Assessment Numeric Evaluation. RESULTS: There were 7 failures: 4 for recurrent instability and 3 for symptoms of pain. Overall, outcomes scores demonstrated mean values of the American Shoulder and Elbow Surgeons Rating Scale of 94.6, Subjective Patient Shoulder Evaluation of 20.0, Western Ontario Shoulder Instability Index of 389.4 (81.5% of normal), and Single Assessment Numeric Evaluation of 87.5. Patients with voluntary instability demonstrated worse outcomes (P = .025), and those with prior surgery of the shoulder also did worse (P = .02). CONCLUSION: Arthroscopic treatment of posterior shoulder instability is an effective means to improve symptoms associated with recurrent posterior subluxation of the shoulder. It can provide predictable success in the setting of unidirectional, nonvoluntary posterior instability without prior surgery.     

Subtalar instability of the foot: A review and results after surgical treatment

Most subtalar ligamentous injuries occur in combination with ankle ligament injuries, but the exact aetiology and the true incidence remain unknown. The aim of this study was to review the problem, propose a definition and to analyze the results of an anatomic reconstructive surgical technique in the treatment of subtalar instability. Twenty-two patients suffering from chronic subtalar instability of the foot were operated with anatomical reconstruction. The cervical, the lateral talo-calcaneal and the calcaneo-fibular ligaments were imbricated and reinforced with the lateral root of the inferior extensor retinaculum. After a minimum of 2 years follow-up the functional results were excellent or good in 18 of 22 (82%) patients and fair or poor in 4 of 22 (18%). All of the patients with unsatisfactory results suffered from residual ankle pain, two of whom also had residual instability. No reoperations have been performed. Surgical complications were seen in three patients, all minor nerve injuries of the lateral branch of the superficial peroneal nerve. These complications had no bearing on the functional results, however. This procedure was found to be feasible in patients with chronic subtalar instability.     

Prospective evaluation of thermal capsulorrhaphy for shoulder instability: indications and results, two- to five-year follow-up

BACKGROUND: Thermal shrinkage of capsular tissue has recently been proposed as a means to address the capsular redundancy associated with shoulder instability. Although this procedure has become very popular, minimal peer-reviewed literature is available to justify its widespread use. PURPOSE: To prospectively evaluate the efficacy of arthroscopic electrothermal capsulorrhaphy for the treatment of shoulder instability. STUDY DESIGN: This nonrandomized prospective study evaluated the indications and results of thermal capsulorrhaphy in 84 shoulders with an average follow-up of 38 months. METHODS: Patients were divided into three clinical subgroups: traumatic anterior dislocation (acute or recurrent), recurrent anterior anterior/inferior subluxation without prior dislocation, and multidirectional instability. Patients underwent arthroscopic thermal capsulorrhaphy after initial assessment, radiographs, and failure of a minimum of 3 months of nonoperative rehabilitation. RESULTS: Outcome measures included pain, recurrent instability, return to work/sports, and the American Shoulder and Elbow Surgeons (ASES) Shoulder Assessment score. Overall results were excellent in 33 participants (39%), satisfactory in 20 (24%), and unsatisfactory in 31 (37%). CONCLUSIONS: The high rate of unsatisfactory overall results (37%), documented with longer follow-up, is of great concern. The authors conclude that enthusiasm for thermal capsulorrhaphy should be tempered until further studies document its efficacy.     

Drop foot after knee dislocation: evaluation and treatment

Although knee dislocations are relatively rare, serious complications make treatment difficult. Common peroneal nerve (CPN) palsy is a debilitating complication and its incidence has been reported as high as 50%. Even after successful ligament construction, unresolved CPN palsy is a major factor contributing to poor outcomes after knee dislocations. CPN palsy is more common with open dislocations, rotatory dislocations, and especially occurs in patients with posterolateral corner injuries. CPN palsy can be readily diagnosed clinically, although a high index of suspicion is needed. The risk versus benefits of surgical exploration in the acute setting is still under debate. Conservative management can be appropriate in the early phase of treatment, however, for persistent nerve damage, surgery is the treatment of choice because it results in better functional outcomes. Neurolysis, primary nerve repair, nerve grafting, and posterior tibialis tendon transfer have all been used by surgeons as viable surgical treatment options. As late surgical treatment of CPN typically results in poor prognosis, awareness of this injury, thorough physical examination and documentation of the nerve injury, and close follow-up are of paramount importance.