Jae Ho Yoo

Oblique Femoral Tunnel Placement Can Increase Risks of Short Femoral Tunnel and Cross-Pin Protrusion in Anterior Cruciate Ligament Reconstruction

Background: A more horizontal femoral tunnel has been emphasized for contemporary anterior cruciate ligament (ACL) reconstruction. However, lowering the femoral tunnel may result in a shorter tunnel. In addition, a more horizontally placed femoral tunnel may have inadequate bone stock at the posterior portion of the tunnel, which can lead to protrusion of the cross-pin (Rigidfix) system for femoral fixation. Hypothesis: A more horizontal femoral tunnel position, particularly via the anteromedial (AM) portal technique, will reduce femoral tunnel length, and a more horizontal femoral tunnel position and anterior-to-posterior pin insertion will increase the risk of Rigidfix pin protrusion. Study Design: Controlled laboratory study. Methods: In 10 cadaveric knees, we measured maximum lengths of the femoral tunnels at the positions of 11:30, 10:30, and 9:30 o’clock using the transtibial technique and at the 10:30 and 9:30 o’clock using the AM portal technique. Then, for each femoral tunnel via the transtibial technique at 11:30, 10:30, and 9:30 o’clock positions, tests were performed for 3 directions of Rigidfix pin insertion using the lateral epicondyle as an anatomical landmark, namely, 15° anterior to posterior (A-P), neutral, and 15° posterior to anterior (P-A). It was then determined whether pins protruded from the posterior cortex. Results: The lengths of femoral tunnels produced using the transtibial technique became shorter as the femoral starting position became more horizontal (51.1 mm, 40.0 mm, and 34.2 mm on average at the 11:30, 10:30, and 9:30 o’clock position, respectively). Tunnels made using the AM portal technique were significantly shorter than those made using the transtibial technique: by 7.6 mm at the 10:30 o’clock and 4.5 mm at the 9:30 o’clock positions on average (P < .001). In addition, increasing obliquity increased the likelihood of Rigidfix pin protrusion, especially when pins were inserted in the A-P direction. Conclusion: The current effort to lower the femoral tunnel position in ACL reconstruction can shorten the tunnel length and compromise the graft fixation at the femur using the Rigidfix system. Clinical Relevance: When an intended femoral tunnel position is more horizontal than the 10:30 o’clock position for ACL reconstruction, a surgeon needs to be cautious regarding a short femoral tunnel, particularly when using the AM portal technique, and possible protrusion of the cross-pin (Rigidfix) fixator.

A case of compression fracture of medial tibial plateau and medial femoral condyle combined with posterior cruciate ligament and posterolateral corner injury

We report a case of compression fracture of anterior margin of medial tibial plateau and medial femoral condyle combined with the posterior cruciate ligament and posterolateral corner disruption. A thirty-seven-year old male had undergone the left knee injury 6 months before. The physical examination revealed positive posterior drawer test and tibial dial test, which evidenced the posterior cruciate ligament and posterolateral corner insufficiency. The plain lateral knee radiographs showed a marginal fracture of the anteromedial tibial plateau and a dimpling on the adjacent part of the medial femoral condyle. On arthroscopy, there were no gross tear of the cruciates, but the posterolateral capsule disclosed stigmata of stretching injury with multiple petechiae and scarring. The compression fracture on the anteromedial side and the stretching injury on the posterolateral side altogether support the mechanism of hyperextension pivoting on the anteromedial side of the knee joint. A small bony lesion around the knee joint should be inspected rigorously with an assumed mechanism of injury for it may herald major ligamentous injury.

A case of intra-articular synovial lipoma of the knee joint causing patellar dislocation

Intra-articular synovial lipoma is rare and clinically manifested mostly by mass effect and occasionally by torsion of the stalk. Patellar dislocation rarely occurs owing to a mass effect of intra-articular tumor of the knee joint. The authors present a case of large intra-articular synovial lipoma at the lateral gutter of the knee joint, which presents as patellar dislocation. A 19-year-old man visited our clinic due to pain and limitation of motion owing to mass at his left knee. MRI revealed an intra-articular soft tissue mass at the lateral gutter of the knee joint with considerable mass effect displacing patella from the trochlear groove. Excisional biopsy confirmed the diagnosis of lipoma, and the final diagnosis was intra-articular synovial lipoma with clinical information. The final radiograph showed well-aligned patella on the trochlear groove. After marginal excision, there was no recurrence or tumor-related morbidity.

Arthroscopic Removal of Separated Bipartite Patella Causing Snapping Knee Syndrome

The bipartite patella is a developmental osseous variant that is found in approximately 2% to 6% of the population, and is bilateral in 50%. The proposed etiologies include old nonunion, osteochondritis, and congenital growth defect. It is often found incidentally around the inferior pole, lateral margin, or superolateral border of the patella. It is usually asymptomatic, but may be related to anterior knee pain. However, separation of the bipartite patella is rare, with 9 cases reported in the literature. The symptomatic snapping knee syndrome may be caused by multiple intra-articular and extra-articular pathology including discoid meniscus, tumors, iliotibial band, popliteus, gracilis, semitendinosus, or biceps femoris tendon. However, no reports exist on separated bipartite patella as the feasible cause of the snapping knee syndrome in the orthopedic literature. This article presents a case of snapping knee syndrome due to separated bipartite patella. The accessory bone was removed by arthroscopy, which has rarely been described in the literature.

Posterior double PCL sign: a case report of unusual MRI finding of bucket-handle tear of medial meniscus

AbstractsAmong the MRI signs of bucket-handle tears of medial meniscus, double posterior cruciate ligament (PCL) sign denotes a low signal band anterior and parallel to the PCL, which looks like another PCL in MR images. If the bucket-handle fragment subsequently tears at the anterior horn, the torn meniscal substance can be displaced to the posterosuperior region of the PCL, and looks like another PCL behind the original PCL. We propose the lesion be called the “posterior double PCL sign” in contrast to the ordinary double PCL sign. We present a case showing the posterior double PCL sign.

A case of pathologic fracture of femur whose primary tumor and occult metastases were ascertained by PET–CT

We report a case of metastatic pathologic fracture of femoral shaft, whose primary cancer was ascertained by positron emission tomography–computed tomography (PET–CT). The abnormally increased biological activity of the space-occupying lesion of the lung was clearly demonstrated by PET–CT. Moreover, the occult bony metastatic lesions were confirmed with evidence of altered biologic activity. The PET–CT should be regarded as a valuable work-up tool for the orthopaedic management of metastatic pathologic fracture of a skeleton, all-the-more as a functional metabolic imaging tool.

Snapping Knee caused by the Semitendinous Tendon - A Case Report -

Snapping syndrome has rarely been reported in the knee. A snapping knee mainly occurs in the case of a translation of the lateral meniscus or a lateral discoid meniscus. Other causes include biceps femoris tendon, semitendinosus iliotibial band, and popliteus tendon. We recently experienced a case of a snapping knee caused by the semitendinosus tendon passing over the medial tibial condyle as a result of trauma.

The Necessity of Deltoid Ligament Repair in Lateral Malleolar Fracture Combined with Medial Clear Space Widening.

목 적: 족관절의 내측 관절 이개를 동반한 외과골절에 대한 수술적 치료 시 파열된 삼각인대에 대한 수술적 복원의 필요성을 알아보고자 하였다. 대상 및 방법: 1996년 1월부터 2002년 2월까지 내측 관절 이개를 동반한 족관절 외과골절로 진단받은 환자 중, 82명의 환자, 82례를 대상으로 하였다. 6 mm 이상의 이개를 보였던 9례에 대하여는 외측 고정과 함께 삼각인대 봉합술을 시행하였으며, 73례는 외측 도달법 만으로 외과골 절 정복 후 정복이 된 경우에는 수술을 마쳤고, 정복되지 않은 경우에는 관통나사못 고정술 만을 시행하여 정복을 시도하였으며, 삼각인대 봉 합술은 실시하지 않았다. 결 과: 외과골절에 대한 정복 및 내고정 만으로 73례 중 65례에서 만족할만한 정복이 이루어졌고, 관통나사못이 필요하였던 경우는 8례였다. 삼각인대 봉합술이 추가적으로 필요하였던 경우는 한 례도 없었다. 최종 추시 시점에 시행한 임상적 평가에서 족관절 운동제한을 보인 례는 한 례도 없었으나, 6례에서 보행시 경도의 통증을 호소하였으며 92%에서 우수, 8%에서 양호의 결과를 보였으며 보통과 불량은 없었다. 방사 선학적 평가에서 술전 평균 내측 관절 이개는 5.89 mm (4.5~13 mm)였고, 최종 추시 시점에 시행한 단순 방사선 소견 상 평균 내측 관절 이 개는 2.54 mm (1.5~3.5 mm)로 95.2%에서 양호 이상의 결과를 보였다. 결 론: 삼각인대 파열로 인한 내측 관절 이개를 동반한 족관절 외과골절의 치료에 있어서, 외과골절에 대한 해부학적 정복 및 내고정 혹은 외 측 면으로부터의 관통나사못 고정을 추가함으로써 만족할만한 결과를 얻을 수 있으며, 이 경우 내측의 삼각인대 손상에 관한 관혈적 봉합술은 필요치 않을 것으로 사료된다.