Biomedical subjects

Jin Hwan Ahn

Publications and source records attributed to Jin Hwan Ahn.

At least 19 recordsLinked to original sources

PubMed2006

Removal of a femoral interference screw that migrated posteriorly, using a posterior trans-septal portal: a case report.

Few cases have been reported in which the femoral interference screw has migrated into the posterior compartment after an ACL reconstruction. It usually requires removal, because it leads usually to mechanical symptom. However, the arthroscopic removal of a screw is a technically demanding procedure, especially in the case of the femoral interference screw that has migrated into the femoral notch (posterior compartment), an intact integrated ACL graft or one that is encapsulated around the screw. We present a case in which a displaced femoral interference screw migrated within the posterior compartment 11 years postoperatively, after the graft had been incorporated at the femoral site. Although it is often technically challenging, through the use of a posterior trans-septal portal, we can successfully remove a displaced femoral interference screw even in the most difficult locations in the posterior compartment.

Adult↗

PubMed2006

Anterior cruciate ligament double-bundle reconstruction with hamstring tendon autografts.

The anterior cruciate ligament (ACL) surgical technique via a 5-strand hamstring tendon autograft is designed with a conventional single-bundle reconstruction that has shown favorable results and an additional posterolateral (PL) bundle reconstruction. The conventional single-tunnel technique is performed for the tibial tunnel, and the double-tunnel technique is performed for the femoral tunnel. The anteromedial (AM) femoral tunnel is prepared with 1 mm of the posterior femoral cortex being left over the top at the 11- to 1-o'clock position. The PL femoral tunnel is prepared with the outside-in technique by use of a 4.5-mm cannulated reamer. The AM bundle is fixed with a rigid fixation system on the femoral side, and the PL bundle is fixed to tie with the miniplate from the outside femur. A double-bundle reconstruction with 5-strand hamstring autografts, in conjunction with a conventional AM bundle and an additional PL bundle, seems to be a very effective method for the treatment of ACL instabilities. Although the long-term clinical outcome of the procedure is yet to be determined, complications including graft impingement, limitation in range of motion, and residual instability have not been observed to date in the first 38 patients who have undergone our technique.

Anterior Cruciate Ligament↗

PubMed2006

Second-look arthroscopic findings of 208 patients after ACL reconstruction.

The aim of this study is to report the arthroscopic subjective findings of reconstructed anterior cruciate ligament (ACL) with good clinical outcome. Graft used for reconstruction was either patella bone-tendon-bone (PBTB) autograft or hamstring tendon [quadrupled semitendinous and gracilis tendon (QSGT)] autograft. From March 1997 to September 2003, among 716 ACL reconstructions 209 knees (208 patients) were available for second-look arthroscopy at a mean 21.2-month (range, 14-70 months) postoperative period. The second-look arthroscopy focused on the evaluation of (1) continuity of the reconstructed ACL graft, (2) subjective graft tension using a probe, (3) the extent of synovial coverage, (4) the prevalence of cyclops or cyclops-like lesion, and (5) bony change after notchplasty. Patellar tendon autograft was used in 80 knees, hamstring tendon autograft in 129 knees. Just prior to second-look arthroscopy two objective clinical evaluations, KT-2000 arthrometer and Lysholm knee score, were performed to verify good clinical outcomes. A comparison between the hamstring tendon group and the patella tendon group, hamstring group showed slightly better results in Lysholm knee scores and KT-2000 arthrometer but there were no statistically significant differences (p>0.05). Undetected partial graft tear was seen in 21 knees (10%). With regard to graft tension, a total of 181 grafts (87%) showed normal tension and 28 (13%) showed slight lax tension. The overall synovial coverage was poor in nine (4%) knees. The synovial coverage was slightly better in the hamstring tendon group. A total of 45 knees (21.5%) showed cyclops-like lesion in variable sizes and locations. Reformation of the notch was seen in 85 knees (40%). In conclusion, the findings of second-look arthroscopy of reconstructed ACL in good clinical outcome patients showed approximately 10% partial graft tear, 5% poor synovial coverage, 20% cyclops-like lesion, and 40% some notch reformation.

Adolescent↗

PubMed2006

Arthroscopic assisted reduction and internal fixation of lateral femoral epiphyseal injury in adolescent soccer player: a report of one case.

Ligament injuries are more common than fractures in adolescents. We operated on an adolescent soccer player, who had a lateral femoral epiphyseal injury using arthroscopic-assisted reduction and percutaneous internal fixation. During second-look arthroscopy 2 years after the first operation, there was articular cartilage congruity, without any visible step-off. The axial alignment did not reveal any residual valgus deformity.

Adolescent↗

PubMed2006

Arthroscopic loose-body removal in posterior compartment of the knee joint: a technical note.

The arthroscopic removal of loose bodies in the knee joints is a relatively common procedure. Quite often intra-articular loose bodies tend to localize at the posterior compartment due to gravity effect. However, it is often technically demanding to find and remove loose bodies located at the posterior compartment of the knee joint arthroscopically. We present the technical aspects of arthroscopic removal of the loose bodies located in the posterior compartment of the knee joint. Loose bodies at posterior compartment were subdivided into six regions in posterior knee compartment with preoperative MRI and arthroscopic findings. Each section needs slight different application of arthroscopic techniques for removal. We retrospectively studied 52 knees in 50 patients who underwent arthroscopic loose-body removal in posterior compartment, in 28 knees, additional posterior trans-septal portal was needed for removal of loose bodies. With the help of trans-septal portal, we have successfully removed the loose bodies even from the most difficult locations in posterior compartment.

Arthroscopy↗

PubMed2006

The modified outside-in suture: vertical repair of the anterior horn of the meniscus after decompression of a large meniscal cyst.

This article describes a modified suture technique designed for the vertical repair of the anterior horn of the meniscus after arthroscopic decompression of a large meniscal cyst. This procedure comprises of three steps: first, the meniscus was pierced vertically using a suture hook and a No. 0 PDS suture. Second, both ends of the No. 0 PDS on the femoral and tibial surfaces of the meniscus were pulled to the outside of the joint capsule using a spinal needle preloaded with suture material. Finally, a skin incision was made adjacent to the suture materials, and both ends were tied. We recommend this technique not only for the vertical repair of the anterior horn of the meniscus after decompression of large meniscal cyst, but also to repair a longitudinal tear of the meniscus.

Arthroscopy↗

PubMed2006

Measurement and comparison of the difference in normal medial and lateral knee joint opening.

This paper reports the amount of medial and lateral knee joint opening in the general population. Knee joint lateral and medial opening at 20 degrees knee flexion was quantified on manual varus and valgus stress test, respectively, with custom made device. One hundred men and women between the ages of 20-60 years were evaluated for their joint openings. Patients with previous knee surgeries or chronic knee pains were excluded from the study. Measurements were done twice by two different orthopedic surgeons who were blinded from each other. The mean age of the study group was 39 years (range 20-60 years) and 43 years for women (range 20-60 years) and 34 years for men (range 20-60). The mean lateral and medial knee joint space opening was 7.0 degrees (range 3-9 degrees ) and 4.1 degrees (range 2-7 degrees ), respectively, in the overall population; in the male population, it was 6.7 degrees (range 3-9 degrees ) and 3.9 degrees (range 2-7 degrees ), respectively, and in the female population, it was 7.2 degrees (range 3-9 degrees ) and 4.3 degrees (range 3-7 degrees ), respectively. Conversion to displacement in millimetres, the overall mean lateral and medial joint displacement was 9.3 mm (range 5.1-13.6 mm) and 4.8 mm (range 3.5-10.7 mm), respectively; for males, it was 9.1 (range 5.1-11.9 mm) and 4.6 mm (range 3.5-7.9 mm), respectively, for females, it was 9.8 mm (range 7.2-13.6 mm) and 4.9 mm (range 3.7-10.7 mm), respectively. The prevalence of the overall population that exceeds 6 mm or more lateral joint space opening was 91% (male 90% and female 92%) and medial joint space was 8% (male 4% and female 12%). Statistically, significant differences were seen between medial and lateral opening in male, female and the overall population (p<0.001). The female population exhibited wider opening in both medial and lateral joint opening than the male population (p<0.05). The interexaminer reliability showed no significant difference (p>0.05). More than 91% of the Korean population showed wide lateral joint space opening in the bilateral knee. However, none complained of functional instability or symptoms except for non-pathologic laxity detected by the physician. We strongly recommend bilateral comparison of the knee that has wide lateral joint opening.

Adult↗

PubMed2006

Arthroscopic all-inside lateral meniscus suture using posterolateral portal.

A new arthroscopic all-inside suture for lateral meniscus posterior horn tear using a single posterolateral portal is described. A lateral meniscus posterior horn peripheral longitudinal tear is often seen with anterior cruciate ligament injury or discoid lateral meniscus tear. Conventional repair methods, such as arthroscopic inside-out, outside-in, or all-inside sutures, can be cumbersome and technically demanding. Our all-inside suture using the posterolateral portal allows thorough visualization of the posterolateral structures, excellent coaptation of torn meniscus, strong knot tightening, and avoidance of inadvertent cartilage injury. The arthroscope is inserted through the anteromedial portal and reaches the posterolateral compartment by a transcondylar approach. A suture hook is introduced into the posterolateral portal without a cannula, penetrates posterior peripheral rim, crosses the tear, and passes through mobile torn fragment. A large amount of No. 0 PDS is passed, so that it curls up inside the joint. After the suture hook is removed, a suture retriever is inserted through the posterolateral portal to pull out 2 ends of the PDS at the same time. The retrieved suture ends are passed through a knot pusher and a 5.5-mm cannula is introduced over the retrieved suture materials for the SMC knot to be tied. A longitudinal tear of lateral meniscus posterior horn is repaired with 2 to 3 sutures.

Adult↗

PubMed2006

Arthroscopic femoral tensioning and posterior cruciate ligament reconstruction in chronic posterior cruciate ligament injury.

For the new arthroscopic femoral tensioning and posterior cruciate ligament (PCL) reconstruction in chronic PCL injury, we make a transtibial tunnel, using the posterior trans-septal portal, while preserving the remnant bundle of the original PCL and meniscofemoral ligament. Also, to preserve the remnant femoral fibers of the PCL and provide femoral tensioning, we manipulate the suture hook with No.1 PDS by hand so that the sharp tip penetrates the remnants of the PCL near the femoral attachment site. After pulling the sutures previously placed at the remnant PCL fibers, the notchplasty osteotome is advanced to the femoral footprint of the PCL to a depth of 1 to 2 mm from the shallow to the deep direction. Then the remnant PCL fibers are detached from the medial femoral condyle, which the authors call the artificial femoral "peel-off" tear. We drill the femoral tunnel using the outside-in technique in the anatomic place of PCL footprint, which is located 1 to 2 mm from the edge of the articular cartilage. This procedure significantly contributes to the posterior stability and proprioception of the knee joint, the remnant femoral fibers and meniscofemoral fibers are preserved to be healed with a graft and subsequently form an integrated structure.

Achilles Tendon↗

PubMed2006

Biomechanical testing of hybrid hamstring graft tibial fixation in anterior cruciate ligament reconstruction.

Hamstring tendon using quadrupled semitendinosus and gracilis autografts is a well-established technique for ACL reconstruction. However, several methods have been used for tibial fixation of the tendon graft. The purpose of this study was to compare the biomechanical characteristics of quadrupled hamstring graft tibial fixation using three different fixation methods. Nine matched pairs (18 specimens) of cadaver tibias were divided into three groups of six specimens. The first group was fixed with only a tapered 30-mm bioabsorbable screw (BIS), the second group was fixed first with a BIS and then the remaining tendon portion was additionally fixed with a titanium cortical screw and spike washer, and the third group was fixed with only a cortical screw and spike washer. A custom-made probe hook was mounted on a load cell (Interface, MFG, Scottsdale, AZ) to measure the ACL tension before and after the final tibial fixation. Group 2 displayed greater mean maximum load at failure than both groups 1 and 3 (p<0.05). The stiffness of the graft nearly doubled in group 2 compared to groups 1 and 3 (p<0.05). All specimens failed by slippage and pullout. Biomechanical testing with cadavers showed that a BIS and additional cortical screw and spike washer fixation to the distal hamstring tendon resulted in higher load at failure and stiffness compared to either BIS or cortical screw and spike washer fixation alone.

Absorbable Implants↗

PubMed2005

Arthroscopic transtibial posterior cruciate ligament reconstruction with preservation of posterior cruciate ligament fibers: clinical results of minimum 2-year follow-up.

BACKGROUND: The transtibial technique for posterior cruciate ligament reconstructions can potentially lead to poor clinical outcomes due to the "killer turn" effect. HYPOTHESIS: Preserving the original posterior cruciate ligament fibers in the reconstruction will contribute significantly to the posterior stability of the knee joint, healing of the graft, and prevention of graft failure. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Sixty-one patients (45 men and 16 women; mean age, 30.4 years) underwent transtibial posterior cruciate ligament reconstruction with preservation of the cruciate ligament fibers; they were reviewed at a mean period of 40.8 months. All patients were assessed with the Lysholm knee score, International Knee Documentation Committee subjective and objective evaluations, and KT-2000 arthrometry. Follow-up magnetic resonance imaging was performed in 40 patients; images were assessed for graft continuity, thickness, and signal intensity. Second-look arthroscopy was performed in 42 patients. RESULTS: The mean Lysholm score improved from 65.8 to 92.9. The final International Knee Documentation Committee subjective evaluation rated all patients as normal or nearly normal, and the objective evaluation showed normal or nearly normal in 59 patients (97%) and abnormal in 2 patients (3%). The mean side-to-side difference on the KT-2000 arthrometer was 2.79 mm. All patients showed well-preserved graft continuity on magnetic resonance images. Mean graft thickness was 9.9 mm in the sagittal plane and 12.3 mm in the coronal oblique plane. Images for all patients revealed homogeneously low signal intensity in the distal portion of the graft, with complete healing of the graft and original posterior cruciate ligament fibers as one ligament. Graft loosening or graft tear by the killer turn effect was not detected in any patients. Second-look arthroscopy revealed complete healing and graft integration, with the original posterior cruciate ligament fibers in all patients. CONCLUSION: In transtibial posterior cruciate ligament reconstructions, poor outcomes from the killer turn effect may be reduced by preserving the original posterior cruciate ligament fibers.

Achilles Tendon↗

PubMed2005

Posterior cruciate ligament reconstruction: double-loop hamstring tendon autograft versus Achilles tendon allograft--clinical results of a minimum 2-year follow-up.

PURPOSE: The purpose of this study was to compare clinical results of arthroscopic posterior cruciate ligament (PCL) reconstructions using double-loop hamstring tendon autograft and Achilles tendon allograft while preserving the original PCL remnant. TYPE OF STUDY: Case-control study of results of treatment. METHODS: From September 1997 to December 2000, 36 patients who received only PCL reconstruction were reviewed retrospectively. Of these, 18 patients received autogenous double-loop hamstring tendon reconstruction (group I) and 18 received Achilles tendon allograft reconstruction (group II). The same PCL reconstruction procedure was performed in both groups. At final follow-up at a minimum of 2 years, patients were evaluated by 4 measures: the International Knee Documentation Committee (IKDC) evaluation, Lysholm knee scores, the posterior draw test, and Telos stress radiography. RESULTS: Between the 2 groups, preoperative demographic factors (age, gender, activity level, and mean duration to surgery) showed no statistically significant difference (P > .05). According to IKDC evaluation of group I, 16 of the 18 knees rated normal or nearly normal, whereas 2 fell into the abnormal category. By the same criteria, 14 of the 18 knees in group II were normal to nearly normal, 3 were abnormal, and 1 was severely abnormal. IKDC scores showed no statistical difference between the 2 groups (P = .98). Postoperative mean Lysholm knee scores were 90 points (range, 78-100) for group I and 85 (range, 70-95) for group II; improvements of 22 and 17 points, respectively. According to the Lysholm knee scores, group I showed slightly better results than did group II, with a statistical significance of P < .01. Telos stress radiography showed the mean difference in posterior translation between the injured and uninjured knees to be 2.2 mm (range, 0 to 7.0 mm) for group I and 2.9 mm (range, 1.0 to 7.0 mm) for group II. The Telos stress test showed no statistical difference between the 2 groups (P = .14). CONCLUSIONS: The clinical outcome was the same for both groups. Despite its comparatively short length and small diameter, the double-loop hamstring tendon autograft was as good as Achilles tendon allograft in PCL reconstruction. LEVEL OF EVIDENCE: Level III, case-control study.

Absorbable Implants↗

PubMed2005

Arthroscopically assisted reduction and percutaneous fixation of dorsal perilunate dislocations and fracture-dislocations.

Perilunate injuries are severe disruptions of the wrist joint that produce variable patterns of injury to the carpal anatomy. Most surgeons advocate an open reduction followed by ligament repair or internal fixation. We tried to reduce and fix the carpal bones under arthroscopic control to minimize surgical trauma and to preserve blood supply. While viewing the articular surface with the arthroscope, the disrupted proximal carpal row was anatomically reduced using Kirschner wires as joysticks, and fixed percutaneously without any repair of the capsuloligamentous tears. Three patients with dorsal perilunate dislocations or fracture-dislocations were treated by this technique. All the patients achieved accurate reduction and stable fixation, and showed successful healing of the carpal fractures with proper alignment after 10 to 12 weeks of immobilization. At 16 to 22 months follow-up, all patients showed normal radiographic findings with no evidence of instability or arthritis. The arthroscopic treatment of acute dorsal perilunate injuries is technically feasible in achieving anatomic reduction and stable fixation. Our preliminary clinical results were encouraging, but the long-term results need to be observed.

Accidental Falls↗

PubMed2004

Clinical outcome of arthroscopic reduction and suture for displaced acute and chronic tibial spine fractures.

This paper reports the clinical outcome of the arthroscopic reduction and pull-out suture technique in acute and chronic displaced tibial spine anterior cruciate ligament (ACL) avulsion fractures. Between April 1997 and December 2000, 14 patients received an arthroscopic reduction and pull-out suturing of displaced tibial spine fractures (ACL avulsion fractures of tibia). Of 14 cases, ten were acute fractures and four were chronic nonunion fractures, in which all patients showed extension limitation. The mean follow-up period was 51 months (ranging from 30 to 80 months). At final follow-up, review of range of motion, Lachman test, anterior drawer test, KT-2000 arthrometer, Lysholm knee score, and Hospital for Special Surgery (HSS) score were evaluated. Compared to conventional pull-out suturing, several key modifications to surgical techniques were used. In all 14 patients, radiological bony union was detected at mean 12.3 weeks (range, 8-16 weeks) after surgery. All patients were able to return to their preinjury activity and sports level. At final follow-up, full range of motion was achieved in all patients. Anterior draw test, Lachman test, and KT-2000 (less than 3 mm side-to-side) were all negative in 13 patients. One female patient, who was 6 years old at the time of surgery, complained of no subjective instability, but showed Lachman grade I, and 5 mm side-to-side difference in KT-2000. She also revealed 10 degrees difference of genu recurvatum deformity. Two children (including the previously-mentioned 6-year-old female patient) showed leg-length discrepancy of 1 cm-the affected legs being longer-at final follow-up. The mean Lysholm knee scores were 95.6 (range, 92-100) and HSS knee scores were 96.4 (range, 91-100). Arthroscopic reduction with modified pull-out suturing technique in displaced tibial spine ACL avulsion fractures showed excellent union rate for both acute and chronic cases, without instability or extension limitations at minimum two-year follow-up.

Acute Disease↗

PubMed2004

All-inside suture technique using two posteromedial portals in a medial meniscus posterior horn tear.

Up to two thirds of patients with anterior cruciate ligament rupture have a combined medial meniscus posterior horn tear. Researchers have proven the importance of repairing this tear to enhance stability after anterior cruciate ligament reconstruction. However, repairing the meniscal tear can be sometimes cumbersome and difficult or even impossible in certain circumstances, especially in places such as the posterior horn of the medial meniscus. We devised a simple and easy method of all-inside suturing of medial meniscus posterior horn tears using a 2-posteromedial portal system. Furthermore, with a modification of our technique, a clinician can not only suture single but also double longitudinal medial meniscus posterior horn tears.

Arthroscopes↗

PubMed2004

Modified inside-out technique for meniscal repair.

A modified technique of the inside-out suture for arthroscopic repair of meniscus is described. Although the conventional inside-out technique is a fine modality of a meniscal repair, it is difficult to perform vertical suture and to attain good coaptation and strong fixation. We introduce a modified inside-out suture, which uses a suture hook, a zone-specific cannula, and a specially designed looped needle for an efficient meniscal repair. The modified inside-out suture technique provides vertically oriented suture, excellent tissue coaptation, and firm fixation. We recommend this technique as an excellent method for repairing a tear in most parts of the meniscus, especially the posteromedial corner.

Arthroscopy↗

PubMed2004

Arthroscopic partial meniscectomy of a medial meniscus bucket-handle tear using the posteromedial portal.

Arthroscopic resection of irreparable bucket-handle tears of the medial meniscus is a commonly performed procedure. Adequate visualization of the posterior horn of the medial meniscus can be a challenging task with the conventional use of the anterior portal. An attempt to resect the posterior horn in a blind fashion may result in iatrogenic damage of the articular cartilage in the posterior compartment, over-resection of a remnant meniscus, or an insufficient resection of the torn fragment. We describe the use of the posteromedial portal for an accurate visualization and resection of the posterior attachment of a bucket-handle tear for arthroscopic partial meniscectomy, as well as detection of other injuries that may be involved in the posteromedial compartment, while avoiding injury to other intra-articular structures during the arthroscopic procedure. We found that the use of the posteromedial portal is a safe and efficient method in removing a bucket-handle tear of the medial meniscus in one piece.

Arthroscopy↗

PubMed2004

Arthroscopic all-inside suture repair of medial meniscus lesion in anterior cruciate ligament--deficient knees: results of second-look arthroscopies in 39 cases.

PURPOSE: To evaluate by second-look arthroscopy the clinical results of arthroscopic all-inside sutures with hook using 2 posteromedial portals for medial meniscus posterior horn (MMPH) tears in patients who underwent concurrent anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Case series. METHODS: From May 1997 to June 2001, 78 knees underwent surgery for MMPH tears with arthroscopic all-inside sutures with hook and concurrent ACL reconstruction. Among them, 39 patients were evaluated with follow-up second-look arthroscopy. All MMPH tears were repaired by arthroscopic all-inside suture technique using 2 posteromedial portals. The second-look arthroscopy was performed, on average, 19 months (range, 6 to 40 months) after the ACL reconstruction and meniscal repair. They were divided into complete healing, incomplete healing, and failure groups. Tear size, type, and location were analyzed. We determined clinical criteria for success in meniscal status as (1) not positive for 4 clinical objective parameters--joint line pain and tenderness, locking or catching, recurrent effusions, and McMurray test; and (2) complete healing of all-inside sutured meniscus during second-look arthroscopy. RESULTS: Among 39 knees assessed by second-look arthroscopy, 32 (82.1%) knees showed complete healing and 6 (15.4%) showed incomplete healing without any positive findings of the clinical symptoms. Furthermore, all cases in the incompletely healed group had complete healing of the posterior horn, which was sutured by an all-inside suture; the incomplete healing was observed between the junction areas of all-inside to inside-out sutures, which was mainly at the posteromedial corner. The success rate was 97.4% (38 of 39 patients) overall for all-inside suture healing. The 1 patient (2.6%) with clinical failure had a retear of the repaired site. The average knee scores improved and all showed less than 2-mm side-to-side difference on KT-2000 testing. CONCLUSIONS: Arthroscopic all-inside vertical suture using a suture hook resulted in a high rate of healing even in large and complex vertical tears. This suturing can be one of the optimal treatments for MMPH tears greater than 1 cm during concurrent ACL reconstruction. LEVEL OF EVIDENCE: Level IV, Therapeutic Study, Cases Series (no, or historical, control group).

Adolescent↗