Diagnosis Of Posterolateral Rotatory Instability Research Articles

Arthroscopic Diagnosis of Posterolateral Rotatory Instability of the Elbow

Posterolateral rotatory instability (PLRI) is the most common form of symptomatic acute and chronic elbow instability. Diagnosis is usually made using a combination of clinical tests and imaging modalities; however, in more subtle forms of instability, these measures may be equivocal. Arthroscopy is a valuable adjunct for diagnosis and treatment of PLRI. It allows direct appreciation of the instability process, quantification of the degree of instability, and identification of concurrent associated pathology. The aim of this technique article is to report a series of reproducible arthroscopic tests used for diagnosis of PLRI with examples of normal and pathologic arthroscopic findings.

Reliability of Magnetic Resonance Imaging Signs of Posterolateral Rotatory Instability of the Elbow

To evaluate radiographic signs of posterolateral rotatory instability (PLRI) on magnetic resonance imaging (MRI). The goal was to establish objective radiographic criteria to aid in the diagnosis of PLRI. The MRI scans of 60 patients were evaluated retrospectively. Two study groups were compared. Group 1 (n = 30) consisted of unstable elbows in which PLRI was confirmed by clinical examination and arthroscopy. Group 2 (stable; n = 30) served as the control group. Patients in group 2 had transient epicondylitis without clinical suspicion of instability. Joint incongruity was analyzed for sagittal views through the radial head and the coronoid tip and for coronal and axial views. Interobserver and intra-observer reliability were evaluated. In the sagittal view through the radial head, average radiocapitellar incongruity differed significantly between groups 1 and 2. In addition, mean ulnohumeral incongruity in an axial view through the motion axis of the distal humerus showed significant differences between groups. Sagittal views through the tip of the coronoid and coronal views did not reveal significant differences in patients with unstable elbows compared with the control group. The current study provides useful MRI criteria indicative of PLRI when combined with physical examination. Cutoff points of 1.2 mm for radiocapitellar incongruity (sagittal view) and 0.7 mm for axial ulnohumeral incongruity (axial view) are suitable to screen for PLRI. Radiocapitellar incongruity greater than 2 mm and axial ulnohumeral incongruity greater than 1 mm are highly suspicious of elbow instability. Diagnostic IV.

Novel Methods for Diagnosis and Treatment of Posterolateral Rotatory Instability of the Knee

Injury to the posterolateral corner structures of the knee can cause posterolateral rotatory instability, a condition that has attracted increased attention over recent years1. This injury is often associated with cruciate ligament injury, and its diagnosis can be difficult unless one has a high degree of clinical suspicion for an injury to the posterolateral corner structures2,3. Although a number of treatment methods have been proposed over the past twenty years2,4-12, there has been considerable controversy regarding the optimal method of surgical treatment for this injury. The consequences of missed or unsuccessfully treated posterolateral rotatory instability can be profound: reconstructed anterior or posterior cruciate ligaments can fail, and persistent posterolateral rotatory instability may eventually cause pain, instability, and even degenerative changes13-17. In this report, we describe the use of an external rotation-valgus stress radiograph for the evaluation and diagnosis of posterolateral rotatory instability, and we describe a new anatomical reconstruction procedure involving use of a split Achilles tendon allograft for its treatment. ### Background Although several physical examination techniques for the detection of posterolateral rotatory instability of the knee have been described18,19, no widely accepted method of objective documentation, such as the use of posterior stress radiographs to identify a posterior cruciate ligament injury, has been established for posterolateral rotatory instability. Consequently, assessment of posterolateral rotatory instability is very subjective and dependent on the examiner's experience. Several biomechanical studies have documented that sectioning of the posterolateral corner structures markedly increases external rotation of the tibia at 30° of knee flexion, whereas sectioning of the posterior cruciate ligament alone does not have the same effect20-22. Consequently, increased external rotation of the tibia relative to the femur at 30° of knee …

Arthroscopic Evaluation of Posterolateral Rotatory Instability of the Knee

Purpose : The purpose of this study was to confirm the efficacy of arthroscopic findings for the diagnosis of posterolateral rotatory instability (PLRI) of the knee. Materials and Methods : We retrospectively evaluated 27 patients (28 cases) who had been operated upon for PLRI between February 1998 and June 2001. All patients underwent preoperative or intraoperative arthroscopic examinations including anterior/posterior cruciate ligament, popliteus tendon, inferior and superior popliteomeniscal fascicle, popliteofibular ligament, lateral meniscus, instability and abnormal popliteomeniscal motion for internal and external rotation. Results : Instability, which means popliteal hiatus widening during internal rotation of the tibia, was identified in all cases (100%). Tear of the inferior and superior popliteomenical fascicle was identified in 24 cases (86%) and abnormal popliteomeniscal motion during rotation was identified in 20 cases (71%). Popliteus tendons were abnormal in 18 cases (65%) with 5 cases (19%) of complete tear and 13 cases (46%) of partial tear or elongation. Conclusion : These results suggest that arthroscopic evaluation of the popliteal hiatus structures in the patients suspected for PLRI of the knee is helpful for diagnosis and the determination of treatment modality.

Instrumented measurement of the posterolateral corner

A new device called the Lars Rotational Laxiometer (Lars Inc, Dijon, France) is introduced to aid in the diagnosis of posterolateral rotatory instability of the knee. This device assigns a quantitative value for tibial external rotation. Three examiners each evaluated a separate group of 30 different subjects (total 180 knees) to obtain side-to-side differences. The subjects had no history of injury, pain, or instability. An external rotation measurement was performed at 30 degrees and 90 degrees of knee flexion. At 90 degrees, the mean side-to- side difference was 4.4 degrees (range, 3.7 degrees to 5.1 degrees); at 30 degrees it was 5.5 degrees (range, 4.7 degrees to 6.3 degrees). There was no significant difference with gender or age. The purpose of this study is to establish baseline side-to-side values for the posterolateral complex in normal knees. Objective values are obtainable with the Laxiometer. Arthroscopy 1998 Jul-Aug;14(5):489-94

Posterolateral rotatory instability of the elbow: usefulness of MR imaging in diagnosis.

To evaluate the efficacy of magnetic resonance (MR) imaging in the assessment of the normal and abnormal ulnar band of the lateral collateral ligament for diagnosis of posterolateral rotatory instability. In nine symptomatic patients and nine asymptomatic subjects, MR imaging was performed with three-dimensional gradient-recalled and fast spin-echo sequences. The nine patients had clinical symptoms suggestive of subtle elbow instability. The components of the lateral collateral ligament were identified; tears of the ulnar band were noted in all symptomatic patients. The anterior fibers of the lateral collateral ligament, including the annular ligament, were intact. All symptomatic patients subsequently underwent surgical exploration and reconstruction. Positive clinical findings were demonstrated at examination performed while the patients were under anesthesia. All tears of the ulnar band were confirmed. With use of appropriate pulse sequences, MR imaging is an effective tool in the preoperative, noninvasive diagnosis of posterolateral rotatory instability.