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Biomedical subjects

Jon K Sekiya

Publications and source records attributed to Jon K Sekiya.

At least 19 recordsLinked to original sources
PubMed2006

Anterior cruciate ligament anatomy and function relating to anatomical reconstruction.

Recently, the interest in surgical techniques that reconstruct the anteromedial (AM) and the posterolateral (PL) bundles of the anterior cruciate ligament (ACL) has risen. This review focuses on the structural as well as the mechanical properties of the ACL and the anatomical details of the femoral origin, midsubstance, and tibial insertion of AM and PL bundles of the ACL. The terminology of AM and PL bundles is chosen according to the tibial insertion and determined by their functional tensioning pattern throughout knee flexion. Close to extension the AM is moderately loose and the PL is tight. As the knee is flexed, the femoral attachment of the ACL becomes more horizontally oriented, causing the AM bundle to tighten and the PM bundle to loosen up. The ACL has been described to be restraint to anterior tibial displacement and internal tibial rotation. The rotational component might be represented by the PL bundle. The femoral origin has an oval shape with the center of the AM close to over-the-top position and the center of the PL close to the anterior and inferior cartilage margin. Tibial and femoral insertions of the ACL are over 3.5 times larger when compared to the midsubstance and tunnel placement is more challenging because of the limited size of potential grafts selection of tunnel site placement. For reconstruction, both bone-patellar tendon-bone (BPTB) and quadrupled hamstring grafts are used. Structural properties of a 10 mm wide BPTB or quadrupled hamstring graft have been reported to be comparable with those of the native ACL.

Anterior Cruciate Ligament↗
PubMed2006

Meniscus transplantation using the femoral distractor.

Accurate tunnel placement, graft passage, and secure suture fixation are key elements in meniscus allograft transplantation. We describe the use of a femoral distractor in meniscus transplantation. Joint distraction on the side of the transplantation by the femoral distractor can dramatically improve visibility and joint access. The distractor is applied after all necessary preparatory work. The distal femoral pin is placed in the supracondylar region on the side corresponding to the side to be transplanted. To avoid injury to the peroneal nerve, the proximal tibial pin is placed medial to lateral for both medial and lateral transplantations. The tibial pin is placed at a level approximately 1 to 2 cm below the tibial tubercle. The knee is then held in the flexion angle that affords the best visualization arthroscopically (typically between 60 degrees and 90 degrees of flexion). Gradual distraction is then applied with the distraction rod until adequate visualization is obtained. The case then proceeds with tunnel or trough creation, graft delivery, and peripheral repair. The improved visualization and access provided by the femoral distractor markedly simplifies the more challenging aspects of meniscus transplantation, helping to ensure precise tunnel placement, facilitate graft passage, and aid in accurate suturing.

Femur↗
PubMed2006

Clinical outcomes following isolated lateral meniscal allograft transplantation.

PURPOSE: The purpose of our study was to determine the clinical outcomes following isolated lateral meniscal allograft transplantation. METHODS: Thirty-two patients were retrospectively reviewed following isolated lateral meniscal allograft transplantation. Twenty-five were available for subjective follow-up, and 17 were available for a complete physical examination and postoperative radiographs. The average duration of follow-up was 3.3 years (range, 2 to 6 years), and the average age of the subjects was 30 years (range, 19 to 45 years). In all, 17 patients had bony fixation and 8 had suture fixation of the anterior and posterior horns of the meniscal allograft. RESULTS: Ninety-six percent of patients believed that their overall function and activity level were improved following surgery. Short Form-36 (SF-36) physical and mental component summary scores for these subjects were higher than age- and sex-matched scores from the US population. Joint space narrowing of the transplanted lateral compartments was not significantly different when compared with the joint space narrowing of the lateral compartment of the contralateral knee. In addition, preoperative and postoperative radiographic joint space measurements of the involved lateral compartment were significantly associated with subjective assessment, symptoms, sports activity score, Lysholm score, and final International Knee Documentation Committee (IKDC) rating at latest follow-up. Finally, patients fixed with the bony technique had significantly better range of motion, according to IKDC criteria at latest follow-up, compared with the suture fixation group. CONCLUSIONS: Our results suggest that isolated meniscal allograft transplantation can be a beneficial procedure in properly selected symptomatic patients with a lateral meniscus-deficient knee. The data also suggest that earlier meniscal transplantation, before the onset of significant joint space narrowing, may result in improved outcomes. Finally, bony fixation may have a significant advantage over suture fixation, particularly with regard to knee range of motion. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Adult↗
PubMed2006

Open and arthroscopic treatment of multidirectional instability of the shoulder.

Multidirectional instability of the shoulder can be a difficult diagnostic and therapeutic dilemma for orthopaedic surgeons. First described by Neer and Foster, the mainstay of treatment is usually conservative, with most patients doing very well with nonoperative management. In patients with recalcitrant symptoms, surgical treatment primarily has been aimed at addressing the pathologically increased capsular volume. Newer studies suggest that the pathology also includes abnormal labral morphology and perhaps inadequate neuromuscular control. The arthroscopic treatment of multidirectional instability has come to have comparable results to open techniques when the multifactorial nature of the disease is recognized and the multiple techniques are used in combination to fully treat all pathology. Thermal capsulorrhaphy cannot be recommended at this time, except perhaps as an adjunct to other capsular plication or capsulorrhaphy techniques. The advantages of a less invasive procedure make arthroscopic capsular plication attractive, but it is associated with increased technical difficulty and a steep learning curve. Further studies are needed to distinguish a clear advantage of one over the other. Regardless of the technique used, the key to success is addressing the capsular laxity and redundancy to restore anatomic capsuloligamentous tension without overconstraining the shoulder.

Arthroscopy↗
PubMed2006

Microfracture of the hip in athletes.

Most studies addressing treatment of chondral injuries have involved the knee. Various techniques have been used in the knee. Microfracture has shown excellent results in the knee. Chondral injuries of the hip are common in athletes with labral tears and femoroacetabular impingement. The microfracture technique is now being used in the hip joint. Indications include full-thickness cartilage loss or unstable flap on a weight-bearing surface. An important contraindication is the patients unwillingness to follow the postoperative protocol and rehabilitation plan. The microfracture technique in the hip is similar to that in the knee. Postoperatively, patients use a continuous passive motion and are flat foot (20 lbs.) weightbearing for 8 weeks. Early results following microfracture in the hip have been encouraging.

Acetabulum↗
PubMed2006

Nonsurgical management of lateral side injuries of the knee.

Non-surgical management of posterolateral corner (PLC) knee injuries is reserved for specific isolated mild to moderate injuries. There has been a relative scarcity of studies discussing non-surgical management existing secondary to the relative rarity of isolated PCL injuries. In these specific cases, a few studies have shown non-surgical management to result in satisfactory outcomes. This review of the literature outlines the outcomes and treatment options for posterolateral corner (PLC) knee injuries, which is based on the grade of the injury. However, no matter what the grade of injury, it is crucial to rule out other associated deficiencies before undertaking a nonoperative approach in the management of the posterolateral corner of the knee.

Humans↗
PubMed2006

Symptomatic os acromiale.

Os acromiale, the joining of the acromion to the scapular spine by fibrocartilaginous tissue rather than bone, is an anatomic variant that has been reported in approximately 8% of the population worldwide. It is more common in blacks and males than in whites and females. Although it is often an incidental finding, os acromiale has been identified as a contributor to shoulder impingement symptoms and rotator cuff tears. When nonsurgical management of a symptomatic os acromiale fails to relieve symptoms, surgical intervention is considered. Options include os acromiale excision, open reduction and internal fixation, and arthroscopic decompression. Excision usually is reserved for small to midsized fragments (preacromion) or after failed open reduction and internal fixation. Persistent deltoid dysfunction may result from excision of a large os acromiale. Open reduction and internal fixation preserves large fragments while maintaining deltoid function. Cannulated screw fixation has been shown to result in good union rates. Arthroscopic techniques have shown mixed results when used for treating impingement secondary to an unstable os acromiale. Associated rotator cuff tears may be addressed arthroscopically or through an open transacromial approach, followed by open reduction and internal fixation of the os acromiale.

Acromion↗
PubMed2006

Meniscal allograft transplantation.

Meniscal allograft transplantation is a reasonable treatment option for the young patient with symptomatic meniscal deficiency. Although clinical results are promising, in most studies only mixed procedures have been performed, with short- or medium-term follow-up. Important potential prognostic factors include patient selection, severity of degenerative changes, limb stability and alignment, graft sizing and processing methods, graft placement, and graft fixation. The use of meniscal allograft transplantation should be considered a salvage operation for the difficult clinical dilemma of meniscal deficiency in young patients. Nonetheless, in carefully selected patients, this procedure can predictably relieve compartmental symptoms, and, in conjunction with anterior cruciate ligament reconstruction, restore knee stability. In addition, the partial restoration of meniscal function provided by this procedure may slow the degenerative arthritic process.

Animals↗
PubMed2006

Two techniques for anterior cruciate ligament tibial fixation with a bicortical screw: an in vitro study of neurovascular risk.

We compared the distance to neurovascular structures between exit holes for screws drilled toward the fibula in a medial to lateral orientation (16 cadaveric knees; experimental group) versus screws drilled the standard way, perpendicular to the cortex of the proximal tibial metaphysis (19 cadaveric knees; control group). A bicortical screw was used for tibial fixation, specimens were dissected, and the major neurovascular structures were identified. The screw exit hole on the posterior tibial cortex was found, and a fine caliper was used to measure distances from the hole to the neurovascular structures. The 2 groups differed significantly in distances to the popliteal bifurcation (mean difference, 6.8 mm; P = .019), the anterior tibial vein (mean difference, 9.7 mm; P<.001), and the anterior tibial artery (mean difference, 10.9 mm; P<.001), with the distances larger in the experimental group. There was 1 tibial artery injury in the control group. The groups did not differ significantly with regard to distances to the common peroneal nerve and the tibial nerve (P>.05). During bicortical screw placement in the proximal-medial tibial metaphysis, aiming toward the fibula significantly reduces the risk for vascular injury, as evidenced by there being no injuries, increased distances, and increased margin of safety from vascular structures.

Anterior Cruciate Ligament↗
PubMed2005

A biomechanical comparison of arthroscopic sliding and sliding-locking knots.

PURPOSE: To evaluate biomechanical characteristics of 3 arthroscopic sliding and sliding-locking knots and the square knot, the gold standard used in open surgery. TYPE OF STUDY: Biomechanical investigation. METHODS: Four different knot types (Weston, square, Duncan loop, and Nicky's) were tested in 5 configurations in a closed-loop system on a materials testing device. Three of the 5 knots were backed up with 3 reverse half-hitches and alternating posts and all sliding and sliding-locking knots were tied using an arthroscopic technique. Twelve knots of each configuration were tested for loop security with a 7-N preload, and for knot security with load to failure at a strain rate of 1.25 mm/second and cyclic loading of a 30-N force for 50 cycles. RESULTS: No knots subjected to the 7-N preload failed or slipped and all had similar elongation (0.1 +/- 0.1 mm) except Nicky's knot (0.3 +/- 0.2 mm). There was no significant difference in load at failure for the square knot (178 +/- 14 N), the Weston knot backed with 3 half-hitches (168 +/- 14 N), the Duncan loop (160 +/- 20 N), or Nicky's knot (148 +/- 13 N). Most knots with 3 half-hitches failed with rupture at the knot. Under cyclic loading, no knots failed and none elongated greater than an average of 0.3 mm. CONCLUSIONS: All knot configurations maintained high loop security. All sliding and sliding-locking knots backed with 3 half-hitches had load at failure comparable to the square knot. With cyclic load testing, all knots tested elongated minimally. Additionally, this study confirms that all knots, even the sliding-locking Weston knot, are best backed up with 3 half-hitches alternating posts and directions of the throws. CLINICAL RELEVANCE: Sliding and sliding-locking knots are becoming increasingly popular among arthroscopic shoulder surgeons. This study provides a biomechanical basis for the clinical use of these arthroscopic knots and compares them with the gold standard, the open square knot.

Arthroscopy↗
PubMed2005

Arthroscopic labral repair and capsular shift of the glenohumeral joint: technical pearls for a multiple pleated plication through a single working portal.

The arthroscopic treatment of shoulder instability is becoming increasingly popular with recent clinical studies showing similar success rates comparable to open procedures. These improved success rates are likely due to a better understanding of the pathoanatomy of shoulder instability and addressing all injured structures including labral tears and capsular injury and stretching. I present a new arthroscopic technique for shoulder stabilization that makes use of already known techniques by sequentially repairing the labral tear and performing a capsular shift through multiple, separate pleated plications through a single working portal. This technique allows for an anatomic labral repair with a capsular shift as large as desired by performing as many additional tucks of capsule for plication as needed, comparable to open techniques with less surrounding tissue trauma. This technique is actually easier than more traditional arthroscopic methods, and the multiple pleats may provide a load-sharing effect dispersed through each pleat, which may decrease the risk of load failure.

Arthroscopy↗
PubMed2005

Clinical outcomes after isolated arthroscopic single-bundle posterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the clinical outcomes after arthroscopic single-bundle posterior cruciate ligament (PCL) reconstruction in patients with isolated grade III PCL injuries. TYPE OF STUDY: Retrospective review. METHODS: Twenty-one patients who underwent an isolated arthroscopic single-bundle PCL reconstruction for the treatment of a grade III PCL injury between 1989 and 1998 were included in the study. There were 15 male and 6 female patients with an average age of 38 years (range, 20 to 62 years). The length of follow-up was 5.9 years (range, 2.6 to 11 years), and the average time from injury to surgery was 4.5 years (median, 1.3 years; range, 2 weeks to 25 years). All patients completed a subjective evaluation and 14 patients returned for a physical examination and radiographs. One patient underwent an acute reconstruction (<3 weeks), 4 had a subacute (<3 months), and 16 underwent a chronic (>3 months) reconstruction. The anterolateral bundle of the PCL was reconstructed using an Achilles tendon allograft passed through femoral and tibial bone tunnels. RESULTS: The overall average Activities of Daily Living Scale (ADLS), Sports Activities Scale (SAS), and SF-36 scores were 79.3, 71.6, and 98 points, respectively. There was a significant difference identified when the ADLS (91.3 v 75.6) and the SAS (90.4 v 65.8) scores of the subacute/acute group were compared with those of the chronic reconstruction group. Using the International Knee Documentation Committee (IKDC) subjective assessment, 57% of the patients had normal/near normal knee function, and 62% had a normal/near normal activity level. The average extension and flexion losses were 1 degrees and 5 degrees , respectively. Instrumented laxity examination revealed that 62% had less than a 3-mm and 31% had a 3- to 5-mm side-to-side difference in corrected posterior displacement. Radiographs at follow-up showed that 75% had normal/near normal findings according to IKDC guidelines. CONCLUSIONS: The clinical outcomes after arthroscopic single-bundle PCL reconstruction in this study produced a satisfactory return of function and improvement in symptoms. All patients in this study had improved laxity of at least 1 grade. When compared with chronic reconstructions, acute reconstructions had statistically significant better ADLS and SAS scores. LEVEL OF EVIDENCE: IV, case series.

Achilles Tendon↗
PubMed2005

Posterolateral corner reconstruction of the knee: surgical technique utilizing a bifid Achilles tendon allograft and a double femoral tunnel.

Reconstruction of the posterolateral corner of the knee has received increased attention in the recent literature. Basic science studies have helped us determine the 3 critical structures of the posterolateral corner: the lateral collateral ligament (LCL), the popliteus tendon, and the popliteofibular ligament. We have developed an anatomic posterolateral corner reconstruction that most closely resembles these 3 key structures and is based on the work of previous authors. Our technique is performed using a single Achilles allograft. The bone plug is secured in a femoral tunnel at the anatomic attachment of the popliteus tendon with an interference screw. The Achilles tendon is then split approximately 1 to 2 cm distal to the bone plug into 2 segments: (1) the popliteofibular ligament portion that is passed through a fibular tunnel starting at the anatomic attachment of popliteofibular ligament and fixed with a biointerference screw and (2) the static portion of the popliteus tendon securing this through a tibial tunnel passed from posterior to anterior right at the musculotendinous junction of the popliteus. The anterior limb of the Achilles tendon exiting the fibula is then brought back around, secured to the fibular attachment of the LCL with a suture anchor, and is then passed through a separate femoral tunnel placed at the anatomic attachment of the LCL.

Achilles Tendon↗
PubMed2005

Percutaneous correction (humeroplasty) of humeral head defects (Hill-Sachs) associated with anterior shoulder instability: a cadaveric study.

PURPOSE: The goal of our study was to determine whether a bone tamp could be used to correct a Hill-Sachs lesion by a unique technique that we developed termed "humeroplasty." TYPE OF STUDY: In vitro cadaveric study. METHODS: We created reproducible Hill-Sachs lesions in 14 cadaveric humerii, which we then reduced with a curved bone tamp using our proposed technique. Paired t tests, with the significance set at P < .05, were then used to compare the prereduction and postreduction depths, widths, lengths, and volumes of the lesions. RESULTS: The average prereduction defect measurements were 8.9 mm deep, 16.3 mm wide, 24.1 mm long, and 1,755 mm3 in volume. The average postreduction defect measurements were 1.6 mm deep, 6.2 mm wide, 10.4 mm long, and 50.3 mm3 in volume. A statistically significant improvement (P < .001) was seen in all parameters. CONCLUSIONS: Our technique was able to consistently and significantly restore all measured parameters of the Hill-Sachs lesions using a curved bone tamp. This reduction to a "small" defect may reduce the higher rate of recurrence normally found with the surgical treatment of shoulder instability when "large" Hill-Sachs lesions are present. CLINICAL RELEVANCE: Humeroplasty potentially might reduce the higher rate of recurrence observed when the surgical treatment of shoulder instability involves the presence of large Hill-Sachs lesions.

Adult↗
PubMed2005

Treatment of acute and chronic anterior cruciate ligament-posterior cruciate ligament-lateral side knee injuries.

Knee dislocations are rare but devastating injuries. The ACL-PCL-lateral side injury combination is representative of the challenges these injuries present. Early management is focused on vascular integrity. When possible, acute repair and reconstruction within 3 weeks from injury is preferred. Chronically deficient knees generally will require lateral side reconstruction rather than repair and may require limb realignment. Addressing all injured structures is imperative to afford the best chance at a reasonable outcome. Good results with surgery are possible, but some degree of persistent disability is to be expected.

Anterior Cruciate Ligament↗
PubMed2005

Biomechanical analysis of a combined double-bundle posterior cruciate ligament and posterolateral corner reconstruction.

BACKGROUND: Failure to address both components of a combined posterior cruciate ligament and posterolateral corner injury has been implicated as a reason for abnormal biomechanics and inferior clinical results. HYPOTHESIS: Combined double-bundle posterior cruciate ligament and posterolateral corner reconstruction restores the kinematics and in situ forces of the intact knee ligaments. STUDY DESIGN: Controlled laboratory study. METHODS: Ten fresh-frozen human cadaveric knees were tested using a robotic testing system through sequential cutting and reconstructing of the posterior cruciate ligament and posterolateral corner. The knees were subjected to a 134-N posterior tibial load and a 5-N.m external tibial torque at multiple flexion angles. The double-bundle posterior cruciate ligament reconstruction was performed using Achilles and semitendinosus tendons. The posterolateral corner reconstruction consisted of reattaching the popliteus tendon to its femoral origin and reconstructing the popliteofibular ligament with a gracilis tendon. RESULTS: Under the posterior load, the combined reconstruction reduced posterior translation to within 1.2 +/- 1.5 mm of the intact knee. The in situ forces in the posterior cruciate ligament grafts were significantly less than those in the native posterior cruciate ligament at all angles except full extension. Conversely, the forces in the posterolateral corner grafts were significantly higher than those in the native structures at all angles. Under the external torque with the combined reconstruction, external rotation as well as in situ forces in the posterior cruciate ligament and posterolateral corner grafts were not different from the intact knee. CONCLUSIONS: A combined posterior cruciate ligament and posterolateral corner reconstruction can restore intact knee kinematics at time zero. In situ forces in the intact posterior cruciate ligament and posterolateral corner were not reproduced by the reconstruction; however, the posterolateral corner reconstruction reduced the loads experienced by the posterior cruciate ligament grafts. CLINICAL RELEVANCE: By addressing both structures of this combined injury, this technique restores native kinematics under the applied loads at fixed flexion angles and demonstrates load sharing among the grafts creating a potentially protective effect against early failure of the posterior cruciate ligament grafts but with increased force in the posterolateral corner construct.

Adult↗