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Comparison of different kinematic methods for determining the hip joint center

Introduction: Identification of the hip joint center (HJC) is crucial in determining the alignment and motion of the lower limb, which is important during biomechanical researches, or other clinical applications such as navigation surgeries. Purpose: The purpose of this study is to compare the accuracy of different kinematic methods for obtaining the center of hip joint, in order to find the optimal motion tract recommended during the kinematic assessment. Methods: In this cadaver study, the center of hip joint was calculated from kinematic data acquired by performing three different passive motions (flexion-extension [FE], adduction-abduction [AA], and circumduction [CIR]), and the data was compared to the actual position of femoral head determined via anterior arthrotomy of hip joint. The geometric sphere fitting method was used, and the motion arc zone was segmented into different intervals for analysis. Results: The results showed that with CIR motion of femur, the calculated HJC had the highest accuracy in relationship to the actual femoral head center, and abduction-adduction motion had the poorest accuracy. Regarding the best motion arc zone, a better accuracy was found when the motion range was from 10° to 40°. Conclusion: Different kinematic methods may have different results. In conclusion, when evaluating the HJC via kinematic method, CIR motion at a motion arc zone of 30° is recommended.

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Treatment for single-level degenerative disc disease with posterior dynamic stabilization: Minimum 5 years follow up

Background: In recent years, increasing numbers of patients have exhibited degenerative disc disease (DDD). However, diagnosis of DDD is difficult. Discography, particularly provocative discography, is the most important diagnostic tool for DDD. In addition, treatment of DDD remains controversial. Traditionally, spinal fusion is considered the gold standard for treating DDD. But adjacent segment disease (ASD) remains a problem after applying fusion techniques. Numerous studies have analyzed the effectiveness and safety of treating DDD through posterior dynamic stabilization by using the Dynesys system (Zimmer Spine, Memphis, TN, USA). However, the indications for treatment using Dynesys remain controversial. Purpose: The aim of this study was to record the surgical outcome of applying posterior dynamic instrumentation to treat single-level DDD in carefully selected patients. Methods: We retrospectively reviewed patients with a diagnosis of single level DDD between July 2007 and September 2011. Nineteen patients were treated at our institution with posterior dynamic stabilization (Dynesys, Zimmer Spine, Memphis, TN, USA). Nineteen patients were enrolled in the study, and seven of them received a discogram to determine the pain origin from DDD. Results: For all patients, the mean NRS decreased from 5.11 ± 1.55 preoperatively to 2.26 ± 1.37 postoperatively (p = 0.001). The mean ODI decreased from 41.47 preoperatively to 14.95 postoperatively (p ＜ 0.001). There were four cases with radiographic halo signs at one screw, and two cases with the L5 screw broken (one right, one on both side). None of these patients had ASD that relates to the development of spondylolisthesis and no major surgery- related complication was noted at follow up. Our outcome assessment questionnaire indicated that successful results were reported by 84.2% (16/19) of patients after at least 5 years of follow up. Conclusion: In conclusion, under careful case selection, patients with single-level DDD treated with Dynesys exhibited satisfactory clinical outcomes at midterm follow-up.

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Retrograde intramedullary titanium elastic nail fixation: An alternative to traditional osteosynthesis surgery for patients with superior pubic ramus fracture

Introduction: Treatments for superior pubic ramus fracture remain controversy. There are several surgical options for patients with superior pubic ramus fractures, including intramedullary screw placement, minimally invasive plate osteosynthesis surgery, and plate-rod system fixation. However, no one has been shown to be superior to another. Purpose: We report the perioperative results and surgical outcomes of patients with superior pubic ramus fracture underwent retrograde intramedullary titanium elastic nail (RITEN) insertion and fixation. Methods: A series of 9 patients with 11 superior pubic rami fractures were treated with this technique in a single institute. The detail of surgical procedure was also described. Results: All fractured superior pubic rami were united in a mean duration of 3.28 months. No perioperative complication was noted among these patients. One loose backward implant was noted 28 days after the index surgery. The backward nail was removed and the fracture was united at 5-month postoperatively. Conclusion: RITEN insertion for superior pubic ramus fracture is a simple surgical treatment as well as an effective treatment for fracture healing.

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The findings of intra-articular injuries and the early complications in using arthroscopy-assisted surgery for tibial plateau fractures

Background: Arthroscopic reduction and internal fixation (ARIF) for tibial plateau fracture has been reported to provide direct visualization of intra-articular fragments, achieve accurate fracture reduction, and yield less soft tissue stripping. However, the incidence of postoperative complications in patients treated with ARIF remains unclear. Purpose: We conducted a series study of patients with tibial plateau fracture receiving ARIF, evaluated their intra-articular injuries, and followed up their postoperative conditions, with a focus on the management of those injuries. Methods: We retrospectively analyzed patients with closed tibial plateau fracture receiving ARIF in our medical center between 1997 and 2015. These patients were treated with arthroscopically assisted reduction and osteosynthesis, and with precise diagnosis and management of associated intra-articular injuries. The arthroscopic findings for the intra-articular injuries were recorded, as well as the postoperative complications such as superficial and deep infections, compartment syndrome, and neurovascular injuries. Results: There were 202 enrolled patients with closed tibial plateau fractures receiving ARIF, including 4 (2%), 80 (40%), 6 (3%), 25 (12%), 32 (16%) and 55 (27%) patients with Schatzker type I-VI, respectively. Anterior cruciate ligament avulsion fracture and lateral meniscus tear were the most commonly encountered intra-articular injuries, and higher incidence of intra-articular injuries occurred in highenergy pattern tibial plateau fractures (p = 0.016). Six patients (3%) suffered from postoperative complications, including four cases of deep infections, and 67% of these complications occurred in patients with Schatzker type VI. No compartment syndrome or neurovascular injury was noted in our series. Conclusion: A variety of intra-articular injuries are common in tibial plateau fractures and can be precisely diagnosed with the use of an arthroscope. ARIF of tibial plateau fractures has the advantages of identifying and treating fractures and concomitant intra-articular lesions in a one-stage surgery. It also provides a lower postoperative complication rate.

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Acute irreducible swan neck thumb: An adolescent case

Swan-neck deformity is described as a flexion posture of the distal interphalangeal joint and a hyperextension posture of the proximal interphalangeal joint. This case had an acute trauma history. The physical examination and the plain X-ray view excluded the collateral ligament and bony injuries. Finally, the incarcerated volar plate at the metacarpophalangeal (MCP) joint was identified as the main cause. After the intra-articular pathology was resolved and the joint position was restored, the symptoms were relieved and thumb functioning recovered.

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Tarsal tunnel syndrome caused by talocalcaneal coalition and a ganglion-A case report and literature review

Tarsal tunnel syndrome is an extrinsic and/or intrinsic compression neuropathy of the posterior tibial nerve which travels through the tarsal tunnel. They may be a space occupying lesion, such as a ganglion cyst, a bony prominence or other etiology. The incidence of double lesions is quite rare. We report a 22-year-old female with combined talocalcaneal non-osseous coalition and a ganglion cyst over the left medial malleolar that lead to left foot tarsal tunnel syndrome. The patient was successfully treated with resection of both lesions. At 6-month follow up, she had a pain-free ankle. Numbness and range of motion improved and no residual Tinel's sign was noted.

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Isolated avulsion tear of the medial meniscus anterior root: A case report and a novel surgical technique

Compared to the more prevalent posterior root tears, injuries of the anterior root of meniscus have been relatively far scarcer. In this article, a case of an isolated medial meniscus anterior root avulsion tear was reported, which was successfully treated with a novel arthroscopic technique that incorporated the coronary ligament for a more anatomical repair. The significance of this report are two folds: (1) to the best of our knowledge, there has only been one such case of an isolated medial meniscus anterior root tear prior to this report; (2) the concept of incorporation of coronary ligament during the meniscus repair has never been mentioned in the literature thus far. With the use of a 3.5 mm double-loaded suture anchor, an anatomical repair was achieved as the anterior root of medial meniscus was fixated not only back to its tibial insertion inferiorly but re-attached to the coronary ligament anteriorly as well. Postoperative magnetic resonance imaging (MRI) at 3 months showed complete healing of the anterior root, and at 6 months the patient were able to resume full sports activities asymptomatically.

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Excessive valgus alignment leading to asymmetric wear of tibia bearing polyethylene and bush in a rotating hinge knee prosthesis for proximal tibial tumor resection

A 37-year-old woman with giant cell tumor with secondary aneurysmal bone cystic change treating with proximal tibia rotating hinge knee prosthesis presented an asymmetric wearing at femoral bushes and tibia hinge bush nine years after surgery. The fixed 7° anatomical design of this prosthesis produces excessive valgus stress leading to contributed asymmetric loading over the interface which resulted in wears of not only the tibia bearing polyethylene but also the tibia hinge polyethylene and femoral bushes. Reconstruct the native mechanical axis remains a main goal to extend the longevity of the implants instead of following the build-in angle of the prosthesis.