跖趾关节内侧副韧带重建术治疗外翻

目的 探讨跖趾关节内侧副韧带重建加跖趾关节成形术治疗外翻疗效.方法 采用改良跖趾关节成形术治疗外翻23例(38足),并对趾畸形的矫正程度、疼痛症状的改善及行走功能的恢复等进行充分评估.结果 本组患者外翻角(HAV)及第一、二跖骨间夹角(IMA)术前、后比较,差异有统计学意义(P<0.05).术后随访(13.6±2.3)个月,疗效优28足,良8足,可1足,差1足,总优良率达94.7%.结论 跖趾关节内侧副韧带重建加跖趾关节成形术能够治疗多种中、重度外翻及合并趾跖关节炎患者,能有效改善足部外形及症状,恢复行走功能,并发症少.     

跖骨近端短缩跖趾关节复位术治疗跖痛症合并重度跖趾关节脱位临床疗效分析

目的探讨跖骨近端短缩跖趾关节复位术治疗跖痛症合并重度跖趾关节脱位的临床疗效。方法采用跖骨近端截骨短缩、跖趾关节复位术治疗的跖痛症合并重度跖趾关节脱位65例,共83个跖趾关节,其中第2跖趾关节68个,第3跖趾关节15个。患足均于手术前后拍摄负重正侧位X线片,测量相关指标,并采用ACFAS、VAS评分对手术前后进行临床评估。结果截骨后跖骨平均短缩长度为5.94 mm。术后跖趾骨夹角、跖骨切线角、跖趾关节间隙及跖趾关节活动度等指标较术前均有改善,差异有统计学意义(P<0.05)。ACFAS评分术前为(44.06±7.54)分,术后为(90.43±3.88)分;VAS评分术前为(8.14±0.97)分,术后为(1.14±0.73)分;各评分术后均较术前明显改善,差异有统计学意义(P<0.05)。结论跖骨近端短缩跖趾关节复位术治疗跖痛症合并重度跖趾关节脱位临床疗效确切。     

足底第2～5跖板损伤治疗的研究进展

跖板(跖盘,plantar plate)位于足跖趾关节底,作为梯形状的纤维软骨板参与跖趾关节构成,对维持跖趾关节稳定有着重要意义[1]。虽有学者将第1跖趾关节处的跖板以及相关组织的过伸性损伤称为人工草坪趾(turf toe)[2]。但跖板损伤引起的足底疼痛、肿胀往往被笼统地称为"跖痛症"。临床医师对其认识不足或漏诊可导致跖趾关节持续性疼痛以及后期关节畸形。近年来国内文献对于跖板,尤其是第2～5跖     

Swanson人工跖趾关节置换术治疗晚期跖骨头骨软骨病

背景：第二跖骨头骨软骨病的基本病理改变是跖骨头关节软骨和髓软骨内骨化障碍。对中晚期患者,大部分学者主张早期手术干预。而目前采用的手术方法多种多样,且各有利弊。目的：观察Swanson人工跖趾关节置换术治疗晚期跖骨头骨软骨病的疗效。方法：2007年5月至2011年3月,利用Swanson人工跖趾关节置换治疗且有完整随访资料的晚期跖骨头骨软骨病患者19例（36足）,男7例（14足）,女12例（22足）;年龄43-76岁,平均57．8岁。单侧2例,双侧17例;病变于第二跖趾关节16例,第三跖趾关节3例;合并躅外翻畸形13例,趾间神经瘤2例。负重位X线片参照Smillie分期：Ⅲ期1例,Ⅳ期11例,Ⅴ期7例。测量并记录术前、术后跖趾关节背伸、跖屈角度。结果：随访时间最长5年,最短14个月,平均3．6年。术后患者跖趾关节处疼痛消失,活动自如,术前跖趾关节活动度：背伸10．6°±2．87°,跖屈18．3°±1．96°;术后：背伸32．9°±1．67°,跖屈36．7°±1．17°,术后与术前关节活动度比较,差异有统计学意义（P〈0．05）。根据美国足踝外科协会Maryland跖趾关节百分评分法对本组患者进行评定,优为90～100分,26足,占72．2％;良为80-89分,8足,占22．2％;可为70-79分,2足,占5．6％。优良率为94．4％。结论：对于年龄较大且处于Smillie分期晚期的跖骨头骨软骨病患者,Swanson人工跖趾关节置换术是一个较好的治疗方法。     

保留足趾的跖趾关节复合组织游离移植修复手关节缺损效果观察

目的观察保留足趾的跖趾关节复合组织游离移植修复手关节缺损的效果。方法将濮阳市红十字医院收治的48例手关节缺损患者随机分为2组,各24例。观察组行保留足趾的跖趾关节复合组织游离移植术,对照组行足趾复合组织游离移植术。随访16个月,评价2组患者的手部功能及并发症发生情况。结果末次随访观察组患者手部功能的主观和客观评分均高于对照组,差异有统计学意义(P0.05)。2组并发症发生率差异无统计学意义(P0.05)。结论保留足趾的跖趾关节复合组织游离移植修复手关节缺损,可显著改善患者手部功能,且对足趾外观无明显影响。     

第1 跖趾关节融合术治疗中重度足拇外翻合并第1 跖趾关节炎

目的探讨第1跖趾关节融合术治疗中重度足拇外翻合并第1跖趾关节炎的临床疗效。方法2016年6月至2018年9月北京中医药大学第三附属医院采用第1跖趾关节融合术治疗中重度足拇外翻合并第1跖趾关节炎患者26例。手术前后于足负重位X线片上测量足拇外翻角(HVA)和第1、2跖骨间角(IMA),采用疼痛视觉模拟评分(VAS)评价足拇趾疼痛情况,采用美国矫形外科足踝协会(AOFAS)足趾、跖趾关节、趾间关节功能评分评价足拇趾功能。术后随访观察切口和截骨端愈合、足拇趾功能恢复、畸形矫正、并发症发生及足拇外翻复发情况。结果所有患者平均随访时间(14.53±2.45)个月(12~18个月)。所有病例中有1足切口乙级愈合,其余切口均为甲级愈合;末次随访时截骨端均愈合,未出现内固定物失效、转移性跖痛及足拇外翻复发。末次随访时,平均AOFAS足趾、跖趾关节、趾间关节功能评分从术前(54.38±5.72)分增高至(82.74±1.68)分,平均HVA、IMA及足拇趾VAS评分较术前明显降低。结论第1跖趾关节融合术治疗中重度足拇外翻合并第1跖趾关节炎畸形矫正效果好,可缓解足拇趾疼痛,足拇趾功能恢复良好,且足拇外翻复发率低、安全性高。     

跖骨头软骨面下弧形截骨改善第二跖趾关节屈曲方向的临床研究

目的 探讨带跖趾关节的第二趾移植再造拇手指过程中,利用跖骨头软骨面下选择性截骨来改善跖趾关节屈曲方向的手术方法和临床疗效. 方法 对21例21指带跖趾关节的第二趾移植再造拇、手指病例,术中在第二跖骨头底部关节囊近侧做截骨口,距跖趾关节面5.0 mm处进入跖骨,弧形截除松质骨,使跖趾关节可以屈曲到90°为止,纵贯或交叉克氏针固定关节,再按常规的再造方法重建动力、神经及血液循环. 结果 本组所有再造指均成活.随访时间6～24个月,其中6例得到长期随访(12 ～ 24个月).再造指的掌指关节被动活动范围65°～85°,平均75°.主动活动范围45°～80°,平均65°.X线片复查显示骨质愈合良好,无关节退性行变表现. 结论 在带跖趾关节的第二趾移植再造拇、手指过程中,采用跖骨头软骨面下选择性截骨的方法能明显增加再造掌指关节主、被动屈伸活动度,是提高再造指掌指关节活动度的较佳方法.     

第1跖趾关节融合结合Weil截骨或关节成形术治疗重度拇外翻

目的探讨第1跖趾关节融合结合Weil截骨或关节成形术治疗重度拇外翻的临床疗效。方法对12例重度拇外翻畸形患者(14足)采用第1跖趾关节融合结合Weil截骨或关节成形术治疗。结果患者均获得随访,时间6~44个月。术后患足外形均得到良好改善,13足拇外翻疼痛及跖痛消失,第2~5跖骨头下顽固性角化症、硬性胼底消失;1足出现第5跖骨外侧转移性跖痛,经垫前足减压垫缓解。术后患者跖趾关节有不同程度僵硬,经主、被动关节锻炼后,足趾活动度均有改善,未影响日常活动,患者步态及穿鞋要求均获得明显改善。末次随访时,患足AOFAS评分85.48分±2.97分,VAS评分2.41分±0.47分,HVA 14.93°±5.35°,IMA 9.68°±1.87°,各项指标均较术前明显改善(P0.01)。结论采用第1跖趾关节融合结合Weil截骨或关节成形术治疗重度拇外翻畸形,能明显改善前足外形,缓解前足行走疼痛,改善肢体功能,提高患者生活质量。     

改良跖趾关节屈曲方向的第二足趾移植再造拇手指

目的　介绍改良跖趾关节屈曲方向的第二足趾移植再造拇手指的方法。　方法　在第二足趾移植时将跖骨头截断 ,并沿矢状面由背侧向跖侧旋转 90°后再行游离移植拇手指再造术共 8例 ,使再造的掌指关节具有类似原掌指关节的活动范围。　结果　 8例均一期成活 ,术后经 12～ 3 6个月的随访 ,外形、感觉及运动功能均获满意恢复 ,其中 ,两点分辨觉在 6～ 10mm之间 ,再造掌指关节伸直位到掌侧被动活动范围最大 80° ,最小 65° ,平均 75° ,主动活动范围最大 70° ,最小 45° ,平均 60° ,X线照片复查 ,骨质愈合良好 ,关节无退行性变表现。　结论　改良跖趾关节屈曲方向的第二足趾移植再造拇手指 ,是一种值得应用的治疗方法。     

背侧入路联合Weil截骨术治疗第2跖趾关节跖板损伤

目的:评价背侧入路联合Weil截骨治疗第2跖趾关节跖板损伤的临床疗效。方法:自2012年6月至2013年12月,采用背侧入路联合Weil截骨治疗第2跖趾关节跖板损伤患者5例8足,平均年龄52岁。术前症状为第2跖趾关节不稳定伴跖痛症。所有患者得到随访,时间6～12个月。采用AOFAS评分及VAS评分评价疗效。结果:术后所有患者第2跖趾关节恢复稳定及跖痛缓解。所有患者VAS评分低于术前,AOFAS评分高于术前。结论:应用背侧入路联合Weil截骨治疗第2跖趾关节跖板损伤可有效缓解跖底疼痛,稳定跖趾关节,降低术后半脱位率及术后关节僵硬发生率低。     

The effects of severe femoral bone loss on the flexion extension joint space in revision total knee arthroplasty: a cadaveric analysis and clinical consequences

Five revision total knee arthroplasties (TKAs) involving severe femoral bone loss were performed in 1994. Each had sufficiently severe femoral bone loss in which collateral ligament origins and posterior capsular attachments were violated. A paradoxical phenomenon was observed in each case. Unlike primary TKAs, in which larger distal femoral bone resection leads to laxity of the knee joint in extension, these cases with severe distal femoral bone loss, after initial component selection, developed the opposite situation, a flexion contracture. It was hypothesized that femoral bone loss involving collateral ligament origins would permit distraction of the tibia below the femur with the knee held in flexion, but when the knee was brought to full extension, intact posterior structures would maintain a normal tibial position. To investigate this hypothesis, six fresh-frozen cadaveric lower limbs were tested in full extension and 45 degrees and 90 degrees of flexion after release of the femoral attachments of the collateral ligaments and the posterior capsule from the femur. Joint space changes were measured via a motion tracking device. Results showed that with loss of collateral attachments, 17.2+/-8.9 mm of joint space is created in 90 degrees of flexion, whereas the joint space in full extension is conserved (1.5+/-1.7 mm). With additional loss of the posterior capsule, the joint space at 90 degrees of flexion increased to 26.2+/-6.1 mm, with minimal changes in the extension gap (3.4+/-0.8 mm). Distal femoral bone loss was associated with an increase in the flexion gap compared to the extension gap.     

The medial crosssover toe: a cadaveric dissection

The development of a medial crossover second toe (second toe crossing over the first toe) is not a rare clinical condition. It often occurs in the setting of hallux valgus, although not exclusively so. The resulting displacement of the second toe can cause pain in shoes, with surgical correction being problematic. The pathologic anatomy of this condition has not been fully described. In an effort to better understand it, dissection of a cadaveric specimen with a full crossover toe is presented. The dissection revealed findings not previously documented. They include medial displacement of the flexor tendons and plantar plate along with deformity of the plate itself. These changes are in addition to contracture of the medial collateral ligaments and the previously described rupture of the lateral collateral ligaments. Both the plantar plate and the collateral ligaments, the two major static soft tissue stabilizers of the lesser MP joint, were found to be significantly involved. Pull on the flexor tendons only accentuated the malalignment of the toe. Clinical Significance: The extensive soft tissue changes explain the difficulty in achieving a successful long term correction of a full medial crossover toe with a soft tissue procedure. With attenuation of the plantar plate and medial displacement of the flexor tendons, there is an imbalance of muscle forces across the MP joint. This muscle imbalance would not be corrected by release of the medial collateral ligament, dorsal capsular release or extensor tendon lengthening. Reconstruction of the collateral ligament is at risk for incomplete correction since it is unlikely to resolve deformity in the plate if already present.     

Mobility of the Ankle Joint: Recording of Rotatory Movements in the Talocrural Joint in vitro with and without the Lateral Collateral Ligaments of the Ankle

A method for graphic recording of rotatory movements in osteoligamentous ankle preparations is described. By this method it is possible to record characteristic mobility patterns in two planes at the same time. The ankle is affected by a known torque, so that the individual mobility patterns are reproducible with unchanged condition of the ligaments. Six amputated legs were investigated in the sagittal and horizontal planes and another six in the sagittal and frontal planes. Mobility patterns were recorded with intact ligaments and after successive cutting of the lateral collateral ligaments of the ankle in the anteroposterior direction. In the sagittal plane increased dorsiflexion was observed after total cutting of the lateral ligaments, while plantar flexion remained unchanged. In the horizontal plane the internal rotation of the talus increased in step with increasing injury to the ligament, particularly when the ankle was plantar flexed. When all collateral ligaments had been cut, an increase in external rotation occurred, especially in dorsiflexion. In the frontal plane the talar tilt increased gradually with increasing injury to the ligaments. Talar tilt was at a maximum in the neutral position of the ankle or in plantar flexion. After total severing of the collateral ligaments, however, talar tilt was most marked in dorsiflexion of the ankle.     

Effects of joint load on the stiffness and laxity of ligament-deficient knees. An in vitro study of the anterior cruciate and medial collateral ligaments

We measured the effects of serial section of the medial collateral ligament and anterior cruciate ligament and of the anterior cruciate ligament and medial collateral ligament on anterior-posterior force-versus-displacement and tibial torque-versus-rotation response curves for seven fresh frozen cadaver knees at zero and 20 degrees of flexion before and after application of as much as 925 newtons of compressive load on the tibiofemoral joint. Section of the anterior cruciate ligament always increased anterior laxity in an unloaded specimen; joint load reduced this increase by a greater amount at zero degrees than at 20 degrees of flexion. Joint load was more effective in limiting anterior laxity in anterior cruciate-deficient specimens at low levels of applied anterior force; at higher levels of applied force, the effects of joint congruency were overcome and ligament restraints came into play. Section of the medial collateral ligament increased anterior laxity in an unloaded knee only for specimens in which the anterior cruciate ligament had been previously sectioned; joint load eliminated this increase at full extension but did not do so at 20 degrees of flexion. The medial collateral ligament was the more important of the two ligaments in controlling torsional laxity. Secondary section of either ligament (the other ligament having been sectioned first) produced a greater increase in laxity than did primary section of that ligament in an intact knee. Increases in torsional laxity due to primary section of either ligament were unaffected by the application of joint load. Joint load reduced increases in laxity that were due to secondary section of the medial collateral ligament.     

膝关节侧副韧带解剖特点与膝关节置换股骨假体旋转定位轴线的关系

目的分析股骨远端内、外侧侧副韧带起点及股骨内、外上髁轴线在全膝关节置换术(totalknee arthroplasty,TKA)中与股骨假体旋转角度的关系。方法对20只正常尸体膝关节标本进行解剖,经外上髁尖分别向内侧侧副韧带深、浅层起点钻孔,行MRI检查,测量矢状位像钻孔部位与内、外后髁几何圆心之间的距离及轴位像股骨髁后髁角(posteriorcondylarangle,PCA)和股骨髁扭转角(condylartwistangle,CTA)。结果内、外侧侧副韧带分浅、深两层,屈曲位深层紧张。PCA及CTA分别为4.50±1.26°及7.10±0.30°,二者差异有统计学意义(P<0.05),且均大于国外的相关报道。矢状位上,内侧后髁关节面圆弧半径为19.38±2.13mm,外侧为19.54±2.13mm,二者差异无统计学意义(P>0.05)。内侧侧副韧带股骨侧深层起点距股骨后髁几何圆心距离(d1)为4.22±0.20mm,较内上髁尖距后髁圆心的距离(d2)7.36±0.13mm小,且差异有统计学意义(P<0.05)。结论内、外后髁关节面的固定旋转轴心恰好通过内、外侧侧副韧带股骨侧深层起点,可以看作膝关节的屈曲固定轴,通过松解不同层面的侧副韧带,可以在TKA中针对性地松解软组织及调整伸屈间隙的平衡,从而矫正各种膝内、外翻及屈曲挛缩畸形。股骨内、外侧侧副韧带深层止点可作为TKA中股骨假体旋转定位的参考标志。     

Limits of movement in the human knee. Effect of sectioning the posterior cruciate ligament and posterolateral structures

We applied specific forces and moments to the knees of fifteen whole lower limbs of cadavera and measured, with a six degrees-of-freedom electrogoniometer, the position of the tibia at which the ligaments and the geometry of the joint limited motion. The limits were determined for anterior and posterior tibial translation, internal and external rotation, and varus and valgus angulation from zero to 90 degrees of flexion. The limits were measured in the intact knee and then the changes that occurred with removal of the posterior cruciate ligament, the lateral collateral ligament, the popliteus tendon at its femoral attachment, and the arcuate complex were measured. The cutting order was varied, allowing us to determine the changes in the limits that occurred when each structure was cut alone and the amount of motion of the joint that was required for each structure to become taut and to limit additional motion when the other supporting structures had been removed. Removal of only the posterior cruciate ligament increased the limit for posterior tibial translation, with no change in the limits for tibial rotation or varus and valgus angulation. The additional posterior translation was least at full extension and increased progressively, reaching 11.4 millimeters at 90 degrees of flexion. The progressive increase in posterior translation with flexion was apparently due to slackening of the posterior portion of the capsule, as the translation nearly doubled when the posterolateral structures subsequently were removed. Removal of only the posterolateral extra-articular restraints increased the amount of external rotation and varus angulation. The average increase in external rotation depended on the angle of flexion; it was greatest at 30 degrees of flexion and decreased with additional flexion. At 90 degrees of flexion, the intact posterior cruciate ligament limited the increase in external rotation to only 5.3 degrees, less than one-half of the 13.0-degree increase that occurred at 30 degrees of flexion. Subsequent removal of the posterior cruciate ligament markedly increased external rotation at 90 degrees of flexion, resulting in a total increase of 20.9 degrees. The limit for varus angulation was normal as long as the lateral collateral ligament was intact. When the lateral collateral ligament was cut, the limit increased 4.5 degrees (approximately 4.5 millimeters of additional joint opening) when the knee was partially flexed (to 15 degrees).(ABSTRACT TRUNCATED AT 400 WORDS)     

膝关节内翻屈曲畸形全膝关节置换的软组织平衡

目的探索对膝关节内翻屈曲畸形患者施行的全膝关节置换（total knee arthroplasty,TKA）软组织平衡技术。方法2001年1月～2005年12月,对实施的86例104膝骨性关节炎（osteoarthritis,OA）行TKA的膝内翻屈曲畸形患者进行回顾性研究,对术中的软组织平衡问题进行讨论。其中男19例23膝,女67例81膝;年龄57岁～78岁,平均66岁。行单侧TKA术68例,双侧18例。均为初次行TKA的OA患者。术前内翻角为6～34°,平均12.3°;其中软组织性内翻占总内翻角的56.7%,骨性内翻占43.3%。术前膝关节屈曲挛缩畸形10°以下21膝,10～19°45膝,20～29°22膝,30°以上16膝,平均18.9°。结果患者术前膝关节平均屈曲挛缩18.9°,术中除4例残留5°屈曲挛缩外,其余患者术中膝关节均能达到完全伸直。术后随访6～72个月,平均37个月,6例残留5～10°屈曲挛缩,余膝关节可达到完全伸直。术前内翻角6～34°,平均12.3°;术后测量股胫角170.3～175.6°,平均174.7°,其中2例残留内翻角〉3°。术中、术后发生并发症6例,其中内侧副韧带股骨起点损伤2例;髌骨弹响2例;脑栓塞及腔隙性脑梗塞各1例,经内科治疗后未遗留神经症状。均无皮肤坏死、切口感染及深部感染发生。结论软组织平衡是矫正膝关节内翻屈曲挛缩畸形的主要手段,良好合理的软组织平衡可使高度畸形的膝关节在TKA术后获得明显的功能恢复和畸形矫正。     

Effects of ligamentous injury on ankle and subtalar joints: a kinematic study.

Using 10 normal fresh cadaveric legs, kinematic effects of ligamentous injuries around the ankle joint were studied while the ankle joint moved from maximum plantar flexion to maximum dorsiflexion in saggittal plane. A series of anteroposterior and lateral sequential roentgenograms was taken both in the normal and subsequently created injured condition, to evaluate instant center of rotation and horizontal rotation pattern in the hindfoot complex. Although the pattern of instant center of rotation of the ankle joint varied among normal condition, the majority fell in a prescribed area. The deviation of instant centers from those in uninjured condition was most evident in lateral ligament injury. The average horizontal rotation between the tibia and calcaneus was 8 degrees in the uninjured condition; 6 degrees in the subtalar joint and 2 degrees in the ankle joint. In both medial and lateral injuries, more rotation in the subtalar joint was noted in plantar flexion phase. In the ankle joint, the degree of excessive rotation in plantar flexion range was greater in lateral injury than medial injury, but that in dorsiflexion range was greater in medial injury. It appeared that while every component of collateral ligaments around the ankle was important in controlling rotation in plantar flexion range, the posterior portion of the deltoid ligament is most important in the forsiflexion range.     

The proximal interphalangeal joint in Dupuytren's disease

A precise excision of the diseased fascia corrects proximal interphalangeal joint deformity in many instances. When excision of the fascia results in a contracture of greater than 30 degrees that has not been corrected to this level by gentle manipulation, then a systematic release of the causative structures is occasionally indicated, paying particular attention to the check rein ligaments of the palmar plate and adherence of shortened collateral and accessory collateral ligaments. Postoperative physical therapy and splinting are necessary, particularly in those cases in which a joint release has been performed. These authors advise against a routine joint release. Ultimately, the failure to regain flexion may be a greater disability than the original loss of extension.     

The relationship between passive ankle plantar flexion joint torque and gastrocnemius muscle and achilles tendon stiffness: implications for flexibility

STUDY DESIGN: Experimental laboratory study. OBJECTIVES: We tested the hypothesis that the muscle fibers and the connective tendinous structures, combined in series, provide the resistance to passive joint movement at the ankle. We also determined the relative association between passive joint torque and each of these 2 elements. BACKGROUND: The reason for individual variation in joint flexibility or tightness is not clearly understood, but the influence of musculotendinous stiffness has been inferred. METHODS AND MEASURES: Each of the subjects (6 women and 6 men) was seated with the right knee extended and right ankle positioned at a 30 degrees , 20 degrees , 10 degrees , 0 degrees , -10 degrees , -20 degrees , and -30 degrees (0, neutral position, positive values reflecting plantar flexion) angle while passive plantar flexion torque was measured. The distal muscle-tendon junction of the medial gastrocnemius was visualized by ultrasonography, and its positional change was defined as muscle belly length change. The whole muscle-tendon unit length change was estimated from joint angle changes, from which Achilles tendon length change was estimated. RESULTS: Both the muscle belly and tendon were significantly elongated as the ankle was dorsiflexed (at 0 degrees the mean +/- SD muscle belly elongation was 10.3% +/- 1.8 %, and the tendon elongation was 2.8% +/- 1.2 %, of the initial length at 30 degrees of ankle plantar flexion), from which stiffness indices were determined both for muscle belly and tendon. The passive torque at 0 degrees , -10 degrees , -20 degrees , and -30 degrees was significantly correlated with the stiffness indices of the Achilles tendon (at 0 degrees , r2 = 0.70 and 0.62 for overall and specific stiffness, respectively; P<.05). A tendon stiffness index, separately obtained from tendon lengthening during maximal isometric contraction, was also correlated with passive ankle plantar flexion torque at 0 degrees , -10 degrees , -20 degrees , and -30 degrees (at 0 degrees , r2 = 0.76; P<.05). The specific stiffness index of the muscle belly was correlated (r2 = 0.47, P<.05) with the passive ankle plantar flexion torque at 0 degrees , but its overall stiffness index was not (r2 = 0.32, P>.05). CONCLUSION: Results suggest that extensibility of the muscle-tendon unit of the Achilles tendon for the most part is related to passive ankle plantar flexion joint torque.