Clinical and radiological comparison between partial and complete resection of the anterior cruciate ligament in patients with mucoid degeneration of the anterior cruciate ligament: a controlled clinical trial.

INTRODUCTION: The pathology of a mucoid degeneration of the anterior cruciate ligament (MDACL) has been mentioned in several publications but due to its rare incidence it is not a well-known pathology. Partial or complete resection of the ACL is the option of choice after failed non-surgical treatment. However, the success rate of both surgical techniques and the subsequent risk of an ACL instability is not known. The purpose of this study was to compare the clinical and radiological outcome between partial resection and complete resection of the ACL in patients with MDACL. MATERIALS AND METHODS: Patients with MDACL verified by MRI and persistent knee pain were treated by partial (Group I) or complete resection (Group II) of the ACL and were included in a controlled clinical trial after unsuccessful conservative treatment for at least 6 months. Demographic, clinical and radiological data including the thickness of ACL, ACL/intercondylar ratio, patient's age at the time of surgery, the presenting symptoms, range of motion and ligament stability assessed by the ACL ligament score (Lachman test) were collected. In addition, Tegner activity score and Lysholm score were evaluated preoperatively and at final follow-up after a minimum of 12 months. RESULTS: At final follow-up with a mean of 16.8 ± 8.8 months (range 12-41; Group I: 18.3 ± 9.7 vs. Group II: 15.3 ± 8.0; ns), all patients were pain free. Postoperatively, positive Lachman tests were noted in all patients (100%) in Group II (n = 5 patients with grade II and n = 5 patients with grade III). In Group I, 8 patients (80%) showed a negative Lachman test (grade I) and 2 patients (20%) a slightly elongated Lachman test with a firm stop (grade II). The mean knee flexion at follow-up examination was 132° ± 7° (range 120°-140°; Group I: 129° ± 9° vs. Group II: 135° ± 4°; ns). In pairwise comparison, flexion angle increased significantly in both groups (Group I: p = 0.0124 and Group II: p < 0.001). Pairwise comparison of thickness of the ACL and ACL/intercondylar ratio prior to and post-surgery in Group I showed non-significant differences. CONCLUSION: Both arthroscopic debridement and complete resection of the ACL lead to improvement of clinical and radiological findings in isolated MDACL. However, complete resection of the ACL will result in higher instability. Therefore, partial resection might be the better treatment option, especially in young patients with MDACL.

Spontaneous healing of acute ACL ruptures: rate, prognostic factors and short-term outcome.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction is considered the first line treatment in ACL rupture. However, some patients return to high intensity sport activities and show a normal knee function without ACL reconstruction. Therefore, aim of this study was to evaluate the rate and prognostic factors of spontaneous healing in patients with ACL rupture and the short-term functional outcome. METHODS: The rate, prognostic factors and short-term functional results of spontaneous healing in patients with ACL rupture were evaluated in 381 patients. Morphology of ACL rupture and extent of posterior tibial slope (PTS) were classified by MR- and x-ray imaging. In patients with normal knee stability in anesthesia examination and healed ACL during the arthroscopy 6 weeks after trauma ACL reconstruction was canceled. IKDC -, Tegner Activity Score, KT 1000 testing and radiological characteristics were collected 12 months postoperatively in these patients. RESULTS: 14.17% of the patients with ACL rupture showed a spontaneous healing after 6 weeks. Femoral ACL-rupture (p < 0.02) with integrity of ligament stump > 50% (p < 0.001), without bundle separation (p < 0.001) and decreased PTS (p < 0.001) was found significantly more often in patients with a spontaneous healed ACL. The average IKDC score was high at 84,63 in patients with healed ACL at 1 year follow-up, but KT 1000 testing was inferior compared to non-injured side. CONCLUSION: Spontaneous healing of a ruptured ACL happened in 14% of the patients. Especially in low-demand patients with femoral single bundle lesions without increased posterior tibial slope delayed ACL surgery should be considered to await the possibility for potential spontaneous ACL healing.

[Biomaterials in orthopedics]. / Biomaterialien in der Orthopädie.

Biomaterials are artificial or natural materials, which are used in living organisms for a wide variety of reasons. Currently, there are biomaterials available for practically all types of tissue and can fulfill temporary and permanent functions. Ideally, materials used for temporary roles should be completely resorbed after the fulfilling the function and those with a permanent role should remain stable within the body. Many of the currently available biomaterials do not possess these optimal features. Those with temporary roles often remain unchanged within the organism or only induce an incomplete regeneration and those with permanent roles suffer biological alterations which reduce the function. Despite the enormous number of biomaterials, it must always be considered whether the therapeutic target can be achieved without using an implant.

Does the anterolateral ligament protect the anterior cruciate ligament in the most common injury mechanisms? A human knee model study.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction still has a risk of re-rupture and persisting rotational instability. Thus, extra-articular structures such as the anterolateral ligament (ALL) are increasingly treated. The ALL however prevents the internal rotation of the tibia and it must be doubted that the ALL protects the ACL in other common injury mechanisms which primarily include tibial external rotation. In this study we aimed to evaluate which extra-articular structures support the ACL in excessive tibial internal and external rotation using a knee finite element (FE) model. METHODS: Internal and external rotations of the tibia were applied to an FE model with anatomical ACL, posterior cruciate ligament (PCL), lateral collateral ligament (LCL), medial collateral ligament (MCL) and intact medial and lateral meniscus. Three additional anatomic structures (anterolateral ligament, popliteal tendon and posterior oblique ligament) were added to the FE model separately and then all together. The force histories within all structures were measured and determined for each case. RESULTS: The ACL was the most loaded ligament both in tibial internal and external rotation. The ALL was the main stabilizer of the tibial internal rotation (46%) and prevented the tibial external rotation by only 3%. High forces were only observed in the LCL with tibial external rotation. The ALL reduced the load on the ACL in tibial internal rotation by 21%, in tibial external rotation only by 2%. The POL reduced the load on the ACL by 8%, the PLT by 6% in tibial internal rotation. In tibial external rotation the POL and PLT did not reduce the load on the ACL by more than 1%. CONCLUSION: The ALL protects the ACL in injury mechanisms with tibial internal rotation but not in mechanisms with tibial external rotation. In injury mechanisms with tibial external rotation other structures that support the ACL need to be considered.

Osteonecrosis of distal tibia in open dislocation fractures of the ankle.

INTRODUCTION: Open ankle dislocation fractures are one of the most severe injuries of the ankle. Development of posttraumatic arthrosis is well known. However, there are just a few case reports describing evidence of posttraumatic osteonecrosis (PON) of distal tibia. The pathophysiological mechanism remains unclear and the question of morphologic or personal risk factors cannot be answered. The goal of this study was to evaluate the morphologic characteristics of open dislocated ankle fractures in correlation with the development of PON to facilitate early identification of patients with higher risk of posttraumatic osteonecrosis. MATERIAL AND METHODS: In this study data from 28 patients with open dislocation fractures of the ankle between 1975 and 2006 found at our databases were evaluated retrospectively. For each patient we documented personal data, mechanism of injury, type of lateral malleolar fracture, severity of open fracture, degree of tibiotalar dislocation, presence of medial malleolar fracture, presence of deltoid ligament rupture, time until joint reduction and kind of surgical treatment. We also documented clinical complications and number of surgeries. Presence of PON was examined by radiographs, magnetic resonance imaging (MRI) or histological analysis. RESULTS: Within 12 out of 28 patients with open ankle dislocation fractures a PON of the distal tibia could be found. Nine out of 15 patients with high-energy trauma and 12 out of 19 patients with type C fibular fracture developed PON. 73% of male patients and 88% of the patients with type III soft tissue damage according to Gustillo developed PON. However, if patients suffered from type C fibular fracture, total talus dislocation and grade III soft tissue damage ("necrotic triad") PON was developed in 100% of cases. Other patient's characteristics like late joint reduction, postoperative infection or bimalleolar fracture showed no higher proportion of patients with PON. CONCLUSION: In this study we were able to identify clinical manifestations and risk factors for the development of PON of the distal tibia. All indentified risk factors were associated with heavy fracture mechanisms leading most likely to a serious devascularisation of at least parts of the distal tibial epiphysis. With regard to presented results early identification of patients with higher risk of PON might be possible and maybe additional treatment options can be initialised to protect patients from this process.