Lower-limb adaptation during squatting after isolated posterior cruciate ligament injuries.

BACKGROUND: While many studies point out that posterior cruciate ligament plays an important role in squatting, not many, if any, have looked into knee kinematics or kinetics for isolated posterior cruciate ligament injuries. This study explores lower-limb adaptation during squatting for asymptomatic patients with isolated chronic posterior cruciate ligament injuries. METHODS: Thirteen research subjects or test participants with isolated chronic posterior cruciate ligament injuries were recruited to analyze the kinematics and kinetics on both sides of their hip, knees and ankle joints during squatting. We adopted ExpertVision™ motion analysis system and two Kistler force plates to record the three-dimensional trajectories of the reflective markers used and the ground reaction forces respectively. FINDINGS: The peak vertical ground reaction force exerted on the participants, their peak support moment and the knee-joint peak extension moment exhibited at their non-involved side are significantly greater than that at their involved side. We also find that the involved side's knee joint (extension moment) exhibits a reduced percentage on the peak support moment contributed by the individual joints, while the joints of the hip and ankle signify increased percentages. INTERPRETATION: In this study, the asymptomatic participants having isolated chronic posterior cruciate ligament injuries tend to shift their weight to their non-involved side, and part of their injured knee-joint load to their ipsilateral joints of the hip and ankle. The causes seem to be a habitual gravity center shift, insufficient muscle strength at the involved side, and a reduced mechanical efficiency in their extensor mechanism.

Minimally invasive fixation of displaced midclavicular fractures with titanium elastic nails.

OBJECTIVES: Clavicular fractures account for 2.6% of all fractures, and more than 80% involve the middle third of the clavicle. Plate fixation has been the most common method of fixation reported but has been associated with complications such as infection, wound breakdown, nonunion, implant failures, poor cosmetic outcome, and local skin numbness. We report on a series of cases receiving minimally invasive insertion of titanium elastic nails (TEN) to fix the displaced midclavicular fractures. DESIGN: Prospective, clinical study. SETTING: Regional referral center. PATIENTS/PARTICIPANTS: From November 2006 to October 2007, we operated on 23 patients (16 men) with displaced (no cortical contact between the proximal and distal fragments radiographically and/or greater than 2 cm of shortening) midclavicular fractures fixed with TEN. The mean age of the patients was 41.57 years. INTERVENTION: All patients with displaced midclavicular fractures were treated with TEN. The nails were inserted from the medial entry point on the sternal end and passed through the fracture site under fluoroscopy monitoring. MAIN OUTCOME MEASUREMENTS: Complications, clavicular shortening after TEN fixation, Constant shoulder score, and Disability of the Arm, Shoulder, and Hand score for functional outcome measurement. RESULTS: Closed reduction was successful in 16 patients, and seven patients needed open reduction. There was no nonunion, infection, nail breakage, or refracture after nail removal in our series. The mean operative wound length was 2.2 cm, and mean clavicular length shortening was 0.32 cm. Iatrogenic perforation of the lateral cortex occurred in two patients, and nail misplacement occurred in one patient requiring revision. All patients followed up greater than 12 months. The mean Disability of the Arm, Shoulder, and Hand score was 6 (range, 0-35; standard deviation, 10.47) and mean Constant score was 96 (range, 78-100; standard deviation, 6.34). CONCLUSIONS: Minimally invasive fixation with TEN is a safe method and can be performed with minor complications. This method of fixation of displaced midclaviclular fractures should result in a good cosmetic appearance and satisfactory stabilization of displaced midclavicular fractures without comminution.

Isolated posterior cruciate ligament injuries associated with closed tibial shaft fractures: a report of two cases.

INTRODUCTION: Knee ligament injuries associated with tibia shaft fractures are usually neglected and treatment is delayed. To our knowledge, no case presentation discusses the clinical result of closed tibial shaft fracture with concomitant ipsilateral isolated PCL injury. In this literature, we report the clinical result of two cases that sustained closed tibial shaft fracture with concomitant PCL injury and discuss the treatment options. MATERIALS AND METHODS: We report the clinical result of two cases that sustained closed tibial shaft fracture with concomitant posterior cruciate ligament (PCL) injury. Case 1 received open reduction with plate fixation for the tibial shaft fracture, and he also received arthroscopic reconstruction of PCL with bone-patellar tendon-bone graft due to neglecting PCL injury 5 months later after fracture fixation. Case 2 sustained left tibial-fibular shaft fracture with isolated PCL injury confirmed by magnetic resonance image on the first day of injury. She received tibia fixation with intramedullary nail and conservative treatment with bracing and rehabilitation for PCL injury. RESULTS: In case 1, the male patient only focused on fracture healing without any knee rehabilitation. His knee flexed deeply for protected weight bearing in the injured leg which may have exacerbated the posterior instability and reduced the possibility of PCL healing. The end result of knee function was poor even though PCL reconstruction was done later. In case 2, the female patient with diagnosed posterior cruciate ligament injury on the day of injury, her knee was immobilized in brace with full extension, which improved PCL healing. In addition, she received rehabilitation of quadriceps strengthening, and hamstring muscle contraction was avoided in her daily activity. After rehabilitation, the female patient did not complain of severe subjective instability even with an obvious posterior translation on posterior drawer test. CONCLUSIONS: We need to perform a careful physical examination of ipsilateral knee in cases of leg fractures, and MRI of knee before surgery if any doubt exists. However, a further research is needed to conclude on the best operation and rehabilitation program in patients with combined tibial shaft fracture and PCL injury.

Patellar tendon ruptures in weight lifters after local steroid injections.

INTRODUCTION: Weight lifting is commonly associated with an increase in knee injury risk. Local steroid injection is thought to be associated with increased risk of spontaneous tendon rupture. The purpose of this report is to describe incidence of rupture of the patellar tendon after receiving multiple local steroid injections in weight lifters. MATERIALS AND METHODS: Seven weight lifters presented at the hospital with ruptured patellar tendon. All the patients had a history of multiple local steroid injections into the patellar tendon. Each patient received surgical treatment within 72 h after injury. RESULTS: After an average follow-up time of 26 months, the mean postoperative Lysholm knee score was 94 and the mean Insall-Salvati measurement was 0.96. All seven athletes returned to weight lifting training at 1 year after the operation. They returned to full competition at 18 months after the surgery. CONCLUSION: For physicians who treat patellar tendonitis, especially in weight lifters, it is important to recognize the contributing factors for tendon rupture especially in those who have had multiple steroid injections. The functional prognosis of the knee improves if the normal length and strength of the injured tendon have been properly restored.