Another clinical examination and MRI check at 6 weekswere performed to verify ligament continuity. Progres-sive rehabilitation of the knee was then started. Eightmonths after the initial trauma a clinical examination(objective IKDC), stress radiography with TELOS de-vice (side-to-side differences between the injured and theintact knees) and an MRI were performed to assess thefunctional status and anatomical aspect of the ligaments.At one year a subjective functional assessment of theACL (subjective IKDC) was performed after interview-ing the patient.Results: 20 patients (i.e. 83%) showed full healing ofthe ACL: normal clinical examination (objective IKDC:17 patients stage A, 3 patients stage B), fully-restoredACL anatomy on distance MRIs, normal functional as-sessment (subjective IKDC ranging from 90 to 100,mean 97; TELOS side-to-side differences ranging from 0to 3mm, mean 2mm). The four failures include an ACLreplaced by heterogenous scarring tissue (objectiveIKDC stage B), a case of non healing and 2 early rupturerecurrences (one at 3 months and the other at 6 months:objective IKDC stage C); the last three cases were re-vised with ACL reconstruction.Conclusion: In cases of full ACL rupture with no dis-placement of ligament fibers a splint-based conservativetreatment enabled anatomical and functional restoration.Such patients can now be pre-selected using diffusion-weighted MRI sequences applied to the knee.

Paper 78: Range of Motion and Quadriceps MusclePower After the Early Surgical Treatment of AcuteCombined ACL and Grade III MCL Injuries: A Pro-spective Randomized Study of 47 Patients JYRKI HALI-NEN, MD, FINLAND, PRESENTING AUTHOR

JAN LINDAHL, FINLAND

EERO HIRVENSALO, FINLAND

ABSTRACTBackground: Early operative treatment of combinedACL and MCL injuries have led to frequent motioncomplications and slow quadriceps muscle power gains.The purpose of this study is to evaluate the effect of earlyoperative or nonoperative treatments of the concomitantMCL injury on knee range of motion and quadricepsmuscle strength in combined ACL/MCL injuries. Wealso wanted to determine the ability of the rehabilitationprogram to restore normal knee motion after early oper-ative intervention.Methods: Forty-seven consecutive patients with com-bined ACL and grade III MCL injuries were randomizedinto two groups. MCL was treated operatively in group I(N 23) and non-operatively in group II (N 24). In both

groups ACL was treated with early reconstruction. Se-quential range of motion, one leg hop test, and isokineticmuscle power measurements were performed.Results: All patients achieved full knee extension. Theamount of flexion deficit was higher in the operatively-treated group at any time interval, but the difference wasstatistically significant only at 6 wk (100? versus 112?,P� 0.009), 12 wk (119? versus 128?, P� 0.043), and at36 wk (130? versus 136?, P� 0.011) after the operation.At 52 wk (132? versus 137?) and 104 wk (134? versus137?) follow-up there was no statistical difference.Quadriceps muscle power deficit at 52 wk was 30.7% inthe operative group and 20.5% in the non-operativegroup (P�0.015), and at 104 wk 14.4% and 9.7% (P�0.2, ns).Conclusions: Early operative treatment of combinedACL-MCL injuries is possible without increased long-term mobilization complications. The rehabilitation pe-riod is long and aggressive physiotherapy is recom-mended. However, nonoperative treatment of MCLallows faster restoration of flexion and quadriceps mus-cle power. At 52 wk follow-up the muscle power wasbetter in the non-operative group. At 104 wk follow-up,there was no statistical difference in the muscle power orin the range of motion of the knee. These results favornon-operative treatment of MCL in combined ACL andMCL injuries.Level of Evidence: Therapeutic Level IKey Words: Rehabilitation; Anterior cruciate ligament(ACL); Medial collateral ligament (MCL); RandomizedControlled Trial, Multiligament injury.

Paper 79: Semitendinosus Tendon Regeneration afterACL Reconstruction: A Morphological and Func-tional Study RIEKO KURAMOCHI, PH.D, JAPAN, PRESENTING

AUTHOR

YUMI NOMURA, MS, JAPAN

AKIKO SANADA, MS, JAPAN

AKIE NISHINO, JAPAN

SO KURIBAYASHI, MD, JAPAN

TORU FUKUBAYASHI, MD, JAPAN

ABSTRACTIntroduction: The semitendinosus (ST) tendon is com-monly used as an autogenous graft for anterior cruciateligament (ACL) reconstruction. Several post-operativestudies reported that the ST tendon regenerates with asimilar histological structure. However, shortening andatrophy of the ST was confirmed more than one yearafter surgery. Moreover, athletes who perform in deepknee flexion, such as dance, judo, and gymnastics com-plained of decreased performance ability due to ST mus-

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cle atrophy. However, the mechanism of muscle atrophyand decreased knee flexion torque has not been reportedand the process of ST tendon regeneration after operationis unclear. Thus, the purpose of our study is to examinethe regeneration process of the ST tendon longitudinallyas well as evaluate the ST muscle function after surgery.Methods: Twenty-nine patients (13 males, 16 females,mean age � SD: 22.3 � 3.8 years) who had obtainedisolated unilateral ACL rupture participated voluntarilyin the present study. All patients were either recreationalor competitive athletes belonging to a high school, col-lege or recreational league team. Arthroscopically as-sisted reconstruction with an autogenous quadrupled ip-silateral ST tendon was performed by the sameorthopaedic surgeon. The same rehabilitation programwas used for each patient. At the time of evaluation(Average: 22.4 months post-operation, Range: 12 to 43months), all patients had returned to their previous sportactivities without any pain or restriction.

Isometric knee flexion torque was measured using adynamometer (Biodex System III, Biodex Medical Sys-tems, NY, USA). Patients were seated in a prone positionwith 0 degrees of hip flexion and the lower body tightlysecured to the seat. Two trials of isometric knee flexionwith maximum voluntary effort were performed for threeseconds at 45, 90 and 105 degrees representing shallowand deep angles of knee flexion, respectively. For each ofthe ACL reconstructed and the contralateral knee, themean torque value of the two trials was calculated andexpressed as a percentage relative to the patient’s bodyweight (%BW).

Magnetic resonance imaging (MRI) scans were usedto calculate the muscle volume of the ST, cross-sectional area (CSA) of the ST tendon, length of theST tendon, and to confirm the presence of the regen-erated ST tendon after harvesting for ACL reconstruc-tion. The patients were in a supine position with theknee in full extension. MRI scans were obtained witha 0.5-T scanner (FLEXART, TOSHIBA Medical Sys-tems, Tokyo, Japan). T1-weighted spin-echo, transaxial se-quences were performed over the thigh perpendicular to thefemoral shaft. The images were taken from the ischialtuberosity to 50 mm below the knee joint space. Toobtain the muscle volume of the ST, the anatomical CSAof the ST from each image was calculated using ScionImage (Scion Corporation, MD, USA). Muscle volumewas determined by summing the anatomical CSA of eachimage times 12 mm which is the slice thickness plus theinterslice gap. The CSA of the ST tendon was alsomeasured using Scion Image (Scion, USA). Tendonlength of the ST was defined as the length from the joint

line of the knee to the distal musculotendinous junctionof the ST.

As an index of recovery, each value of knee flexiontorque, muscle volume, tendon length and tendon CSA inthe ACL reconstructed limb was expressed as a percent-age relative to that in the contralateral limb (% contralat-eral). A paired t-test was used to test for side-to-sidedifferences. Pearson product-moment correlation coeffi-cient was used to examine the relationship between thevalues for every measured. One-way ANOVA and Fish-er’s LSD post-hoc test was used to test for differencebetween degrees of the tendon regeneration to asses theknee flexion torque and muscle volume. The thresholdfor statistical significance was set at p�0.05 for all tests.Results: In 27 of the 29 patients, the regeneration of theST tendon-like structure was confirmed. In the remainingtwo patients, a tendon-like structure was not identified.There was no significant correlation between time sincesurgery and % contralateral value of each of knee flexiontorque at 45, 90, 105 degrees, muscle volume, tendonlength and CSA of ST tendon.

The isometric knee flexion torque of the ACL recon-structed limb was significantly lower at each of 45 (133.3 �28.8 vs. 120.2 � 26.9 Nm), 90 (82.1 � 20.9 vs. 57.5 � 21.0Nm) and 105 (65.9 � 21.2 vs. 44.3 � 16.8 Nm) degrees ascompared to that of the contralateral limb. The percentageof the isometric knee flexion torque of the ACL recon-structed limb to that of the contralateral was apparentlylower at 90 and 105 degrees ( 71.5 � 25.0 %, 69.4 � 29.1%) than at 45 degrees ( 91.4 � 17.2 %).

The volume of the ST in the ACL reconstructed limb(120.1 � 55.6 cm3) was significantly smaller as com-pared to the contralateral limb (164.7 � 65.3 cm3). Thus,atrophy of the ST in the reconstructed limb was con-firmed.The tendon length of the ST in the reconstructedlimb (28.8 � 3.1 cm) was significantly longer than thatin the contralateral limb (24.8 � 3.1 cm). Thus longertendon length of the ST was due to a proximal shift of thedistal musculotendinous junction in the ACL recon-structed limb. Furthermore, there was significant corre-lation between % contralateral value of muscle volumeand that of tendon length (r��0.70, r2��0.48).

The CSA of the ST tendon in the reconstructed limb(0.18 � 0.12 cm2) was significantly grater than that inthe contralateral limb (0.081 � 0.049 cm2). In 20 of the29 patients, the CSA of the ST tendons was greater orequal that of the contralateral limb (Group 1). In the 7patients, the CSA of the ST tendons was smaller than thatof the contralateral limb (Group 2). In the remaining twopatients, tendon-like structure was not identified (Group3). Knee flexion torque at 45 degrees was tended to belower Group 2 than Group 1 (p�0.06), and significantly

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lower Group 3 than Group 1 and Group 2. Group 3 hadsignificantly lower muscle volume than Group 2 withlower volume than Group 1.Discussion: The findings obtained in this study indicatethat changes in knee flexion torque are associated withthe degree of morphological changes in the ST muscle-tendon complex after harvesting its tendon for ACLreconstruction.

By analyzing the torque measurements together withthe morphological results, we propose that the regener-ated tendon-like structure is considered to have the sim-ilar function to the native ST tendon when contributingto knee flexion. As our results of this study, CSA of STtendon in the reconstructed limb is better to be biggerthan in the contralateral limb to avoid the decrease of theknee flexion torque and the muscle volume.

From our previous study, we are concerned that theimportant point for the ST tendon regeneration is tocontrol the excessive tension of ST tendon and at thesame time avoiding the muscle atrophy during the earlymonths after operation. To prevent deficits in knee flex-ion torque after ACL reconstructive surgery, therefore,further studies are needed to investigate the operativetechnique and rehabilitation program enable to regener-ate the ST tendon-like structure while maintaining themorphology of the ST.

Paper 80: Functional Regeneration of the Semitendi-nosus Tendon in ACL Reconstruction with Ham-string Autograft: A New Technique of Inducer Graft-ing TAKASHI SOEJIMA, MD, JAPAN, PRESENTING AUTHOR

HIDETAKA MURAKAMI, MD, JAPAN

TAKASHI INOUE, MD, JAPAN

TOMONOSHIN KANAZAWA, MD, JAPAN

KOJI NOGUCHI, MD, JAPAN

MICHIHIRO KATOUDA, MD, JAPAN

KOUSUKE TABUCHI, M.D., JAPAN

MEGUMI NOYAMA, MD, JAPAN

HIDEKI YASUNAGA, MD, JAPAN

KENSEI NAGATA, MD, JAPAN

ABSTRACTObjective: After ACL reconstruction using the tendonsof the semitendinosus (ST) and/or gracilis (G), therehave been reports that harvested ST tendon has thepotential to regenerate and usually the regenerated STinsert to the popliteal fascia. Furthermore there havebeen reports that the postoperative hamstring muscleperformance such as standing active flexion angle andflexion torque at the deep flexion decrease. Therefore,it’s seemed that one of the reasons for the ST muscleweakness is not anatomical attachment of the regener-

ated ST tendon. The purpose of this study is to report thata new technique for functional regeneration of the STtendon using Inducer grafting.Patients and Methods: Fourteen patients underwentACL reconstruction using autologous hamstring tendons.They were 7males and 7 females with a mean age of 22.7at the time of surgery. The average follow up periodsafter surgery were 7.7 months. MRI was taken at 1, 2, 4,6, 12 months after ACL reconstruction. At second lookarthroscopy we evaluated attachment of the regeneratedST tendon.Surgical Technique: After harvesting the ST tendonPassing-pin was inserted along tendon stripper. Passing-pin went through thigh medial skin and retained a loopthread. Inducer graft inserted in the run of the native STtendon the way of pulling out loop thread in knee exten-sion after the ACL graft fixation. As Inducer graft, the STtendon branch to gastrocnemius fascia was divided to theST tendon. The postoperative rehabilitation was same forACL reconstruction without Inducer grafting.Results: In MRI axial view the regenerated ST tendoncould be identified from superior pole of patella level to pesanserinus in all cases. At second look arthroscopy the re-generated ST tendon could be divided to surround softtissue at the attachment all in three cases. And the regen-erated ST tendon was same in the run of the native STtendon.Discussion and Conclusion: Various attachment of theregenerated ST tendon must have an influence on themoment arm of ST muscle at the flexion. The role ofInducer grafting is seemed that tendon canal after har-vesting the native ST tendon connect to pes anserinusand effect like drainage for hematoma. This study wassuggested the possibility that Inducer grafting couldguide to pes anserinus for the regenerated ST tendon andimprove the regeneration rate of the ST tendon.

Paper 81: Microarchitecture of Patella SOPHIE ABRAS-SART, SWITZERLAND, PRESENTING AUTHOR

DANIEL FRITSCHY, MD, SWITZERLAND

PIERRE HOFFMEYER, PR, SWITZERLAND

ABSTRACTObjectives: The aim of this study is to quantify bonemicro-architecture within the patella. High-resolutionmicro-computed tomography (�CT) imaging have beeninstrumental in providing true quantitative and qualita-tive three-dimensional data on baseline bone morphol-ogy. This technique is interesting for its excellent preci-sion for both density and structure measurements.Materials and Methods: 20 fresh-frozen human cadav-eric patella were analysed. The right side and the left side

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