2017 ISAKOS Biennial Congress ePoster #1509

 

Manage the Bony Posterolateral Instability of Knee Through Analytic Diagnosis and Proper Treatment: A 31 Cases Series

CongFeng Luo, MD, PhD, Shanghai CHINA
Yu Zhan, MD, PhD, Shanghai CHINA
Yukai Wang, MD, Shanghai CHINA

Shanghai Jiaotong University Affiliated Shanghai Sixth People's Hospital, Shanghai, CHINA

FDA Status Cleared

Summary

The bony posterolateral instability, which caused by malunion of posterolateral bony structure, was rarely reported in the literature. However, it was found similar to the well-known ligamentous posterolateral instability. We introduce the its concept and report the clinical results by an analytic diagnostic strategy and innovative osteotomy techniques. The final outcome is satisfactory.

Abstract

Background

The posterolateral knee instability which caused by the posterolateral ligament injury, is a hot topic in sports medicine. However, in the management of the posterolateral knee instabilities, another type of instability, which caused by malunion of posterolateral bony structure, was rarely reported in the literature. And such kind of bony instability was found similar to the ligamentous posterolateral instability(LPI) concerning the symptoms and physical examinations. In this case, misunderstanding between the bony and ligamentous posterolateral instability may lead to mal-treatment and unsatisfactory prognosis. In this article, we introduce the “bony posterolateral instability(BPI)” concept and report the clinical results by using systematic management including an analytic diagnostic strategy and innovative osteotomy techniques.

Method

From April 2008 to November 2015, all patients with knee injury history and symptoms of knee instability including pain, “giving-way”, or even unable to walk, were prospectively collected into the study. An analytic diagnostic strategy was applied for evaluation. The diagnosed BPI Patients were treated by osteotomy and had their knee stability, pain and function evaluated pre- and post-operatively.

Results

The clinical results were evaluated at a mean of 43months (range, 12 to 103 months). Posterolateral osteotomy healed at an average of 14.8 weeks. Depression and plateau height was corrected in all cases, which was from 13.5mm and 0.7cm above pre-operatively to 95.6° and 1.4mm at 12-month, respectively. The ROM decreased from 110.5° pre-operatively to 108.2° at 12months follow-up, no significant difference was detected. At the latest follow-up, the KSS, Lysholm score, and VAS were 88.1±10.5, 90.7±8.9 and 0.4±0.8, respectively. The stress test result was negative in all patients postoperatively and no change was observed ever since.

Conclusion

The concept of bony posterolateral instability is a new way of consideration of the posterolateral malunion which from old posterolateral tibial plateau fracture and improperly fixed tibial plateau fracture. Patients can be diagnosed by a CT-stress test-combined strategy, the final outcome of intra-articular osteotomy is satisfactory.