Surgical Injury Of Important Periarticular Muscle Groups In Tha Via Different Minimally Invasive Approaches

Total hip arthroplasty(THA)is one of the most mature joint surgery,a variety of approaches have their own advantages and disadvantages,and this study analyzed surgical trauma of periarticular muscles and postoperative recovery,especially the hip abductor muscles in minimally invasive anterolateral and posterolateral approaches,which were the most commonly used.Through muscle morphological imaging analysis,hip biomechanical analysis,fresh cadaveric experiment analysis and hip function measurement analysis,as previously reported,the minimally invasive posterolateral approach has definite damage to the external rotation muscle group,especially the internal obturator muscle.However,the injury to the hip abductor muscles in the two approaches presented a different result compared with the previous reports.The results showed that the injury was more obvious via the minimally invasive posterolateral approach than the minimally invasive anterolateral approach in terms of muscle volume atrophy and fatty infiltration,and the minimally invasive posterolateral approach also had a significant effect on the hip abduction function.In addition,finite element biomechanical analysis and fresh cadaver experiment confirmed the importance of tendon attachment integrity for the maintenance of the muscle morphology and joint function.PART Ⅰ SURGICAL INJURY OF IMPORTANT PERIARTICULAR MUSCLE GROUPS VIA DIFFERENT MINIMALLY INVASIVE APPROACHES-----IMAGEOLOGY ANALYSISCHAPTER Ⅰ SURGICAL INJURY AND REPAIR OF HIP EXTERNAL ROTATORS IN THA VIA POSTERIOR APPROACH: A THREE DIMENSIONAL MRI-EVIDENT QUANTITATIVE PROSPECTIVE STUDYBackgroud: THA is one of the most successful orthopaedic surgeries since the 20 th century and has gradually become the main treatment for the end-stage diseases in orthopedics.As one of the classical THA(THA)approaches,the posterior approach is widely used.However,the surgical injury of the hip external rotators through the posterior approach can not be neglected and there is a lack of in-depth quantitative researches on the surgical-related injury to the hip external rotators.Purpose: The purpose of this study is to quantificationally analyse the surgical injury of hip external rotators after posterior THA and explore the effect of the muscle repair on the muscle recovery using the MRI three-dimensional reconstruction technique.Methods: 65 patients were eligible to receive a unilateral cementless THA via the posterior approach.During operation,the piriformis tendon was reattached but it was not applicable for the internal obturator muscle.We performed three-dimensional MRI reconstruction of bilateral piriformisand internal obturator muscle preoperatively,6,12 and 52 weeks postoperatively.Muscle volume atrophy and fat infiltration degree were used as the indicators of the muscle injury.Results: Bilateral piriformis and internal obturator muscle were homogeneous preoperatively.Compared with the contralateral side,the volume atrophy and fat-muscle ratio of the piriformis on the operated side increased inconspicuously by 1.64%,0.26%(p=0.062,p=0.071)at 6 weeks and 1.33%,0.20%(p=0.057,p=0.058)at 12 weeks,while 7.28%,2.09%and 15.71%,5.14% for the internal obturator muscle(p<0.01).Up to 52 weeks,the pirformis also showed significant muscle atrophy as well as fatty infiltration(increased by 7.79%,4.21% p<0.01),and 24.18%,11.91%for the internal obturator muscle(p<0.01).Conclusion: The THA via posterior approach significantly harms the hip external rotators.The effective repair could be conducive to the early postoperative recovery of the hip external rotators.CHAPTER Ⅱ COMPARISON OF MORPHOLOGICAL CHANGES OF GLUTEUS MEDIUS AND ABDUCTOR STRENGTH AFTER THA VIA MIS POSTERIOR AND MDL APPROACHESBackground: THA is becoming increasingly mature and minimally invasive,causing less and less damage to the periarticular soft tissues,thus significantly improving the postoperative quality of life of the patients.The functional status of hip abductor muscle group,especially the gluteus medius muscle,directly determines whether the postoperative gait and daily activities of patients are abnormal,which is closely related to the expectation of the patients.It is a general belief among orthopedists that the muscle damage of the hip abductors after THA is theoretically minimal via posterior approach.However,there are little data scientifically supporting the purported advantage.Prupose: The purpose of this study was to quantificationally assess the injury to the gluteus medius(GMED)after THA via the minimally invasive(MIS)posterior and the modified direct lateral(m DL)approaches using the advanced imageology technique.Additionally,the effect of the intraoperative in-situ repair technique on postoperative muscle recovery was to investigate.Methods: 64 consecutive patients enrolled prospectively were randomly assigned to the MIS posterior and the m DL approach group.Three-dimensional MRI reconstruction of bilateral GMED was included in the analysis.Data were collected preoperatively,6,12 and 52 weeks postoperatively.Muscle volume atrophy and fat infiltration degree wereused as the indicators of the muscle injury.Results: Interestingly,in terms of the morphological changes of GMED,the MIS posterior approach showed a more significant degeneration caused by the surgical trauma compared with the m DL approach in both muscle volume atrophy and fatty infiltration from 6 to 52 weeks postoperatively.Bilateral GMED muscle in both groups were homogeneous preoperatively.Compared with the contralateral side,the volume atrophy and fat-muscle ratio of the piriformis on the operated side in the MIS posterior group increased by 16.89%,5.22%(p<0.01)and 7.27%,7.26%(p<0.01)in the m DL group at 6 weeks.At 12 weeks,the volume atrophy and fat-muscle ratio of the piriformis on the operated side in the MIS posterior group increased by 14.05%,7.21%(p<0.01)and 1.91%,5.01%(p=0.098 p<0.01)in the m DL group.Up to 52 weeks,the volume atrophy and fat-muscle ratio of the piriformis on the operated side in the MIS posterior group increased by 1.97%,0.34%(p=0.241 p=0.411)and0.15%,0.03%(p=0.877 p=0.915)in the m DL group.Conclusion: The injury of hip abductors after THA via posterior approach can not be neglected.And,the planned detachment of partial GMED tendon combined with the reconstruction in situ could also achieve the satisfactory muscle recovery.PART Ⅱ 3D FINITE ELEMENT SIMULATION ANALYSIS OF HIP ABDUCTORS IN THA VIA MDL APPROACHBackground: In recent years,3d finite element simulation analysis(FEA)technique has been widely used in medical domain,especially in orthopaedics,stomatology and vascular surgery.In the field of orthopaedics,the finite element simulation analysis has been extensively applied in the evaluation of the stress and strain state in implants,bone or the contact area.Through the analysis of the maximum stress and strain position and the ultimate fatigue strength,the prosthesis design could be optimized continuously to avoid the stress occlusion to the greatest extent,which achieves the personalized biomechanical matching.However,there are few studies using this technique to analyze the musculoskeletal injuries in THA via different surgical approaches.Due to the shortage of fresh cadaver specimens,the application of the finite element analysis in the musculoskeletal injuries becomes more and more important.Purpose: Simulate the detachment of the patial GMED tendon insertion and the in-situ repair in the m DL approach.Reconstruct the important muscle groups as well as ligaments around the hip and load the stress to realize the biomechanical analysis of the hip abductor muscles and the bone structure under different working conditions,which provides the reference and theoretical support for the better protection of the important periarticular soft tissue structures in THA.Methods: CT data of both lower limbs were imported into Mimics21.0 in DICOM format for 3d reconstruction of pelvis,bilateral GMED,and bilateral femur.The reconstructed model was imported into Geomagic Studio 13.0 in STL format for model optimization and surface reduction,which saved as an IGES file.The IGES file was imported into the Hypermesh 14.0 for meshing and the establishment of other important muscle ligaments.Finally,BDF format files exported from the Hypermesh were imported into Patran/Nastran for finite element analysis and stress cloud mapping.Results: The validation of the 3d finite element model is effective and conforms to the physiological and anatomical structure.The femoral head can move freely relative to the acetabulum,and different local stress and strain conditions can be obtained from 3d perspectives.Each component can be individually analyzed for its overall or local stress state,in which the tensile stress and compressive stress can be displayed separately.According to the stress cloud diagram analysis under different working conditions,it can be seen that the contraction force of the GMED muscle on the affected side in one leg standing was significantly reduced when the insertion point of the GMED muscle was not sutured.The stress at the insertion point of the ilium and the femoral greater trochanter was increased.The maximum stress position of the acetabulum and the femoral head was shifted,and the absolute stress value was reduced.When walking slowly,the stress concentration appeared in the 5th lumbar vertebra and knee joint.In addition,the stress value in anterolateral part of the femoral shaft decreased while the posterior medial stress increased.In the in-situ repair condition,the stress and strain values of each part were similar to the normal working conditions.Under the condition of different degrees of fat infiltration,with the increase of the fat-muscle ratio,the stress of each part was similar to that of the GMED tendon detachment without suture,but there was no obvious concentration of stress at the GMED attachmentpoint.Conclusion: Hip abductor muscles group is an important structure to maintain the stability of pelvis,especially plays a vital role in the process of one-leg standing and walking.The in-situ repair technique could well restore the physiological structure of abductor muscles,so as to ensure the better biomechanical status,stronger activity performance and higher quality of life.PART Ⅲ SURGICAL INJURY OF IMPORTANT PERIARTICULAR MUSCLE GROUPS VIA DIFFERENT MINIMALLY INVASIVE APPROACHES -----FRESH FROZEN CADAVERIC EXPERIMENTBackground: THA is performed through a variety of MIS approaches,with different types of injuries to the hip periarticular muscles.At present,the quantitative evaluation methods of muscle injury mainly include imaging reconstruction technique and fresh cadaveric experiment.In the previous work,our research group has completed the imaging quantitative evaluation of muscle injury and published relevant articles.The fresh frozen cadaveric experiment is the most visualized way,and it highlights its research value under the current shortage of cadaver sources.Purpose: The fresh frozen cadaveric experiment was conducted to compare the damage degree of the important periarticular muscle groups via the m DL approach and the minimally invasive posterolateral approach in total hip arthroplasty,which was an necessary supplement for the early imaging analysis.Methods: The bilateral hip joints of each cadaver were randomly assigned to the m DL approach group and the minimally invasive posterolateral approach group.The same type and size prostheses were implanted.All the m DL THA were performed by one experienced surgeon and the minimally invasive posterolateral THA was performed by another experienced surgeon.Firstly,the maximum width diameter and length diameter of the GMED muscle were measured,and the product of the twowas taken as the surface area of the GMED muscle.The average width and length diameter of the injured muscle cut or torn during the operation were measured,and the product was taken as the surface area of the injured muscle.The surface area of the injured muscle divided by the overall surface area of the muscle as a percentage of the muscle damage.Then the width diameter of the tendon tear caused by the breaking or pulling of the GMED was measured directly.The percentage of the injured GMED tendon percentage was calculated.Results: The mean maximum diameter of the GMED muscle in the three cadavers was 148.25 mm,and the mean maximum width diameter was139.11 mm.The mean maximum diameter of the GMED tendon adhesion on the femoral greater trochanteric was 24.16 mm,and the mean maximum width diameter was 51.43 mm.The mean surface area of the GMED muscle was 20623.06mm2,and the mean surface area of the GMED tendon was1242.55mm2.In the minimally invasive posterolateral approach,the mean maximum length diameter of the blunt injury part of the GMED muscle was 71.63mm;the average maximum width diameter was 37.82mm;the average surface area of the injured muscle was 2709.05mm2;and the average percentage of muscle injury was 13.14%.The m DL approach has a mean maximum length diameter 36.47 mm,a mean maximum width diameter 31.75 mm,an average surface area 1157.92mm2,and an average percentage of muscle injury 5.61%(p<0.05).In the minimally invasive posterolateral approach,the maximum length diameter of the blunt injury part of the GMED tendon were 24.16mm;the average maximum width diameter was 22.51mm;the average surface area of the injured tendon was543.89mm2;and the average percentage of tendon injury was 43.77%.The m DL approach to the GMED tendon dissection has an average maximum length diameter 24.16 mm,an average maximum width diameter of18.76 mm,an average surface area of damaged tendon 453.24mm2,and an average percentage of tendon injury 36.48%(p<0.05).Conclusion: The results of the fresh frozen cadaveric experiment were consistent with the previous imaging quantitative analysis results.The minimally invasive posterolateral approach not only had a clear injury to the hip external rotators,but also had a larger percentage of the blunt traction injury to the hip abductor than the m DL approach.This further confirms the role of the m DL approach in protecting the important periarticular muscle groups and the potential muscle injury via the minimally invasive posterolateral THA.PART Ⅳ SURGICAL INJURY OF IMPORTANT PERIARTICULAR MUSCLE GROUPS VIA DIFFERENT MINIMALLY INVASIVE APPROACHES -----CLINICAL ASSESSMENTCHAPTERⅠ THE EFFECT OF THE MIS POSTERIOR APPROACH IN THA ON THE HIP EXTERNAL ROTATION FUNCTIONALITYBackground: The damage of hip external rotators via posterior approach in THA has been confirmed by numerous literatures.In our previous research,the extent of the muscles injury has been also quantificationally evaluated by the imageology reconstruction technique and the fresh frozen cadaveric experiment.The morphological changes of external rotation muscles could directly affect the postoperative external rotation functionality,which is closely related to the quality of life of the patients.Purpose: On the basis of imageology evaluation and the fresh frozen cadaveric experiment,the impact on the postoperative external rotation functionality via the MIS posterior THA has been further studied.Meanwhile,the relationship between the functionality and the morphological changes of the muscle group has been explored.Methods: 65 patients(the same cohort)underwent a unilateral cementless THA via the MIS posterior approach.During operation,the piriformis tendon was reattached but it was not applicable for the internalobturator muscle.Bilateral hip external rotation range measurement was conducted on each patient by the same medical practitioner preoperatively,6,12 and 52 weeks postoperatively.Results: The external rotation range of motion(ROM)of the bilateral hip joint was at the same baseline level preoperatively(p=0.066),while it was limited obviously on the operated side at 6 weeks postoperatively(average of 36.75°,p<0.01).At 12 weeks,it got closed to the normal value,but the difference was still significant(average of 40.09°,p<0.01).After 52 weeks of rehabilitation,the external rotation angle completely recovered(average of 42.43°,p=0.482).There was no statistical significance in the hip external rotation range on the contralateral side during the entire follow-up(p>0.05).Conclusion: MIS posterior approach could significantly impair the hip external rotation functionality in the early postoperative period.The recovery of the functionality of hip external rotation is not corresponding to the morphological changes of the external rotators.Functional compensation of the related muscle groups might be another important factor.CHAPTER Ⅱ THE COMPARISON OF THE HIP ABDUCTOR STRENGTH AND THE ABDUCTION FUNCTIONALITY IN THA VIA THE MIS POSTERIOR APPROACH AND THE MDL APPROACHBackground: Different approaches in THA have different effects on the soft tissue around the hip.The previous imageology studies and fresh frozen cadaveric experiment have analyzed the different injury types of the hip abductor muscle group via the m DL approach and the MIS posterior approach,and the blunt injury of the hip abductors and the superior gluteal nerve through the violent traction after MIS posterior THA could not be ignored.And the result of the planned detachment combined with the in-situ repair of the GMED and GMIN tendon might be satisfactory.Purpose: On the basis of imageology evaluation and the fresh frozen cadaveric experiment,the impact on the abductor muscle strength as well as the abduction functionality via the MIS posterior and the m DL approach has been further studied.Meanwhile,the relationship between the whole abduction functionality and the muscular morphological changes as well as the postoperative pain was also to explore.Methods: 64 patients(the same cohort)were randomly assigned to the m DL approach group and the MIS posterior approach group.Bilateral hip abductor muscle strength and the abduction range were measured for each patient at preoperative,6 weeks,12 weeks and 52 weeks postoperatively.The hip abduction range was used to reflect the abduction functionality.And the postoperative pain was evaluated by Vas pain score.Results: Preoperatively,due to pain and disuse,the abductor musclestrength of the affected side was significantly lower than that of the contralateral side in both groups(MIS posterior,35.53% reduced;m DL,35.62% reduced;p<0.01).At 6 weeks postoperatively,neither MIS posterior group nor m DL group presented an obvious amelioration of the muscle strength(MIS posterior,30.06% decreased;m DL,39.60% decreased;p<0.01).The abductor strength increased rapidly from 6 to 12 weeks,but there was still a statistical significance compared to the contralateral side(MIS posterior,14.31% decreased;m DL,17.47% decreased;p<0.01).Eventually,at the 52-week follow-up visit,the abductor strength on the operated side of both approaches reached the normal level(MIS posterior,0.86% decreased,p=0.221;m DL,0.66% decreased;p=0.127).Preoperatively,due to the chronic hip joint disease,the abduction angle on the operated side was less than that of the contralateral side in both groups,including the m DL approach group(33.82 ° 42.54 ° p < 0.01),and the MIS posterior approach group(31.69 ° 42.62 ° p < 0.01).At 6 weeks,the abduction angle in both group were improved,but it was still much smaller than the contralateral side,including the m DL approach group(37.43 °42.50 ° p < 0.01),and the MIS posterior approach group(37.77 ° 42.65 ° p< 0.01).12 weeks postoperatively,the abduction angle in both group were close to the contralateral side,the statistical differences still existed,including the m DL approach group(42.07 ° 42.71 ° p < 0.01),and the the MIS posterior approach group(41.69 ° 42.54 ° p < 0.01).Up to 52 weeks,the abduction angle in both group were returned to the normal level,including the m DL approach group(42.75 ° 42.82 ° p = 0.602),and the the MIS posterior approach group(42.65 ° 42.69 ° p = 0.832).There were no statistic differences between the two surgical approaches in the postoperative pain from 6 to 52 weeks(MIS posterior: 7.15,5.62,1.77,0.69;m DL: 7.36,5.71,1.79,0.68;Min p=0.092).Conclusion: The m DL and the MIS posterior THA both have an impact on the abductor strength as well as the abduction functionality,thus it proved again that the blunt injury to the abductor muscles caused via the posterior approach should not be ignored.Additionally,it is also worth noting that postoperative rehabilitation of abductor muscle strength are conjunct results of multiple factors,especially the pain,rather than determined by the muscle morphorlogical changes or a certain surgical approach alone.