ACL Damage and Deficiency is Associated with More Severe Preoperative Deformity,Lower Range of Motion at the Time of TKA

Background

ACL status varies in the arthritic knee during TKA.

Questions/Purposes

The purpose of this study was to examine clinical features and intraoperative findings associated with stages of ACL degeneration.

Methods

Coronal deformity, ROM, intra-articular degenerative patterns, and ligament releases were assessed for 1656 knees during TKA. Common patterns of deformity and severity of degenerative change were assessed as a function of the severity of ACL deficiency.

Results

Of the 1656 knees assessed, 27% had a normal ACL, 55% exhibited damage, and 18% exhibited complete absence of the ACL. Increased coronal deformity and lower preoperative ROM was associated with ACL deficiency. Increased chondral and meniscal damage and more extensive osteophyte formation were also found. More extensive ligament releases were required in ACL-deficient knees.

Conclusions

The status of the ACL is predictive of the need for increased surgical deformity correction. A better understanding of ACL status is an important consideration during in choosing TKA as opposed to unicompartmental arthroplasty. The status of the ACL should be considered in planning for implant choice in TKA.

     

Anterolateral Ligament of the Knee Shows Variable Anatomy in Pediatric Specimens

Background

Anterior cruciate ligament (ACL) reconstruction failure rates are highest in youth athletes. The role of the anterolateral ligament in rotational knee stability is of increasing interest, and several centers are exploring combined ACL and anterolateral ligament reconstruction for these young patients. Literature on the anterolateral ligament of the knee is sparse in regard to the pediatric population. A single study on specimens younger than age 5 years demonstrated the presence of the anterolateral ligament in only one of eight specimens; therefore, much about the prevalence and anatomy of the anterolateral ligament in pediatric specimens remains unknown.

Questions/purposes

We sought to (1) investigate the presence or absence of the anterolateral ligament in prepubescent anatomic specimens; (2) describe the anatomic relationship of the anterolateral ligament to the lateral collateral ligament; and (3) describe the anatomic relationship between the anterolateral ligament and the physis.

Methods

Fourteen skeletally immature knee specimens (median age, 8 years; range, 7–11 years) were dissected (12 male, two female specimens). The posterolateral structures were identified in all specimens, including the lateral collateral ligament and popliteus tendon. The presence or absence of the anterolateral ligament was documented in each specimen, along with origin, insertion, and dimensions, when applicable. The relationship of the anterolateral ligament origin to the lateral collateral ligament origin was recorded.

Results

The anterolateral ligament was identified in nine of 14 specimens. The tibial attachment point was consistently located in the same region on the proximal tibia, between the fibular head and Gerdy’s tubercle; however, the femoral origin of the anterolateral ligament showed considerable variation with respect to the lateral collateral ligament origin. The median femoral origin of the anterolateral ligament was 10 mm (first interquartile 6 mm, third interquartile 13) distal to the distal femoral physis, whereas its median insertion was 9 mm (first interquartile 5 mm, third interquartile 11 mm) proximal to the proximal tibial physis.

Conclusions

The frequency of the anterolateral ligament in pediatric specimens we observed was much lower than other studies on adult specimens; future studies might further investigate the prevalence, development, and functional role of the anterolateral ligament of the knee.

Clinical Relevance

This study expands our understanding of the anterolateral ligament and provides important anatomic information to surgeons considering anterolateral ligament reconstruction concomitantly with primary or revision ACL reconstruction in pediatric athletes.

     

Extra-articular tenodesis combined with an anterior cruciate ligament reconstruction in acute anterior cruciate ligament tear in elite female football players

Purpose

The growing popularity of elite soccer among female participants has led to increased incidents of anterior cruciate ligament (ACL) ruptures. Many authors underline a positive glide after ACL reconstruction (ACLR), especially in women. In fact, an isolated intra-articular ACLR may be inadequate to control rotational instability after a combined injury of the ACL and the peripheral structures of the knee. Extra-articular procedures are sometimes used in primary cases displaying excessive antero-lateral rotatory instability. The purpose of this case series was to report subjective and objective outcomes after combined ACL and lateral extra-articular tenodesis (LET) with a minimum 4-year follow-up in a selected high-risk population of elite female football players.

Methods

Between January 2007 and December 2010, 16 elite Italian female football players were included in the study. All patients underwent the same surgical technique: anatomical ACLR with autogenous semitendinosus and gracilis tendons. After the intra-articular reconstruction was performed, an additional extra-articular MacIntosh modified Coker–Arnold procedure was carried out. Patients were assessed pre- and post-operatively with the subjective and objective International Knee Documentation Committee (IKDC) evaluation form, Tegner activity scale (TAS) and Lysholm score. Joint laxity was assessed with KT-1000 by measuring the side-to-side (S/S) differences in displacement at manual maximum (mm) testing.

Results

At a mean follow-up of 72.6?±?8.1 months, two independent examiners reviewed all players. All of the patients had a fully recovered range of motion. Lachman test was negative in all patients (100 %). The evaluation of joint laxity and clinical evaluation showed a statistically significant improvement. No patients experienced complication or a re-rupture.

Discussion

The rationale of combining extra-articular procedures with ACLR is to restrict the internal rotation of the reconstructed knee, taking advantage of its long lever arm and thus providing more stability in the rotational axis and preventing the ACL graft from undergoing further excessive strain.

Conclusions

The combination of an LET with ACLR in elite female football players demonstrated excellent results in terms of subjective scales, post-operative residual laxity and re-rupture rate with no complication, and a complete return to sport activity.

     

Macroscopic evaluation of the anterior cruciate ligament in osteoarthritic patients undergoing total knee arthroplasty

Background

Sacrifice of the anterior cruciate ligament (ACL) is currently common practice during total knee arthroplasty (TKA). However, patients who receive an ACL-retaining TKA maintain more normal knee kinematic patterns than those without an ACL. Additionally, satisfactory survival and function more than 20 years after bicruciate-retaining TKA has recently been reported. The purpose of this study was to compare the percentage of knees with a visually intact ACL prior to TKA surgery with previously reported values.

Methods

A total of 247 knees (216 consecutive patients) that underwent TKA were retrospectively evaluated. The preoperative diagnosis for all patients was primary OA. The macroscopic appearance of the ACL at the time of surgery was retrospectively assessed using routinely recorded digital photographs and classified as normal, moderately damaged (fissured), or completely ruptured. Both normal and moderately damaged ACLs were defined as intact.

Results

Ninety-four percent (233/247) of the knees had an intact ACL (normal or moderately damaged). This value is higher than that found in previous reports.

Conclusions

Our results show more candidates for bicruciate ligament-retaining TKA surgery than reported previously. This suggests that improved techniques for bicruciate-retaining TKA would be clinically useful and could benefit a large number of patients.

     

Combined posterolateral corner and acute anterior cruciate ligament injuries in an adolescent cohort: a magnetic resonance imaging analysis

Purpose

Failure of a reconstructed anterior cruciate ligament (ACL) has significant morbidity in the paediatric and adolescent patient population. Untreated concomitant posterolateral corner (PLC) injury is an identified cause of failed ACL reconstruction; however, the injury pattern has yet to be defined for the paediatric population.

Methods

Magnetic resonance imaging (MRI) studies of the knee performed between 1 January 2009 and 1 January 2013 were retrospectively reviewed. Imaging reports indicating an intra-substance injury of the ACL were reviewed, and all associated injured structures were recorded. Injury patterns were categorised by age, gender, physis status and associated injuries. Logistic regression and chi-square analyses compared ACL disruptions with and without concomitant PLC injuries.

Results

One hundred and twenty-eight patients (74 boys and 54 girls, average age 15.27 years) sustained an ACL disruption. Concomitant injury to the PLC was seen in 13.3 % of injuries. Associated PLC injuries were significantly associated with lateral meniscus injury and Segond fractures. Lateral meniscus injury was predictive of PLC injury (p?=?0.05) upon logistic regression analysis.

Conclusion

Concomitant PLC injuries were found in 13.3 % of all ACL disruptions on MRI analysis. Lateral meniscus injuries associated with an ACL disruption were predictive of concomitant PLC injury. Combined injury of the ACL and lateral meniscus should prompt close scrutiny to PLC structures.

     

Prospective analysis using a patient-based health-related scale shows lower functional scores after posterior cruciate ligament reconstructions as compared with anterior cruciate ligament reconstructions of the knee

Purpose

This study evaluated the treatment outcome of posterior cruciate ligament (PCL) reconstruction using the Medical Outcome Study 36-item Short-Form Health Survey (SF-36), a patient-based quality of life (QOL) questionnaire comparing it with anterior cruciate ligament (ACL) reconstruction.

Methods

Patients who underwent reconstruction at our center for PCL (n?=?24) or ACL (n?=?197) injury were studied. The patients were evaluated using SF-36, visual analogue scale (VAS) for knee pain, Lysholm scale, posterior or anterior tibial translation and range of motion (ROM) before surgery until 24 months after surgery. Results were compared.

Results

In the ACL group, all evaluation methods showed significant improvement after surgery. In the PCL group, however, improvement was observed in only three of eight subscales of the SF-36, Lysholm score and posterior tibial translation after surgery. In intergroup comparison, the PCL group showed inferior performance in three subscales of the SF-36, Lysholm score and ROM for flexion compared with the ACL group.

Conclusions

The surgical outcome of PCL reconstruction was inferior to that of ACL reconstruction both in patient-based and conventional doctor-based assessments. An improved surgical technique for PCL is required.

     

Long-term outcome of anterior cruciate ligament tear without reconstruction: a longitudinal prospective study

Purpose

To analyse subjective and objective long-term outcomes of patients with anterior cruciate ligament (ACL)-deficient knees and limited demands regarding sportive activities. This subgroup of patients might be well-treated without ligament reconstruction.

Methods

We included 303 patients with unilateral tears of the ACL and conservative treatment into a prospective study. Mean age at injury was 33.8 (min. 18, max. 66) years. Follow-up was 27.1 (min. 21.3, max. 31.5) years. Follow-up examinations were conducted 12 and 27 years after injury. At the last follow-up we analysed 50 patients completely. To evaluate clinical and radiological outcomes we used the Lysholm score, Tegner activity scale, visual analogue scale for pain (VAS-pain), KOOS and Sherman score.

Results

Subjective outcome (Lysholm score and VAS-pain scale) improved between the 12th and 27th year after anterior cruciate ligament tear. At the same time activity level (Tegner activity scale) decreased. Also, arthritis (Sherman score) worsened over time. Twenty-seven years after injury, 90 % of the patients rated their ACL-deficient knee as normal or almost normal; 10 % of the patients rated it as abnormal. The findings of this study show that there is a subgroup of patients with ACL tears who are well treated with physiotherapy alone, not reconstructing the ligament. Also, other authors found this correlation between activity level reduction and better subjective outcome.

Conclusions

Conservative treatment of an ACL tear is a good treatment option for patients with limited demands regarding activity. Patient age, sportive activities and foremost subjective instability symptoms in daily life should be considered when deciding for or against ACL reconstruction.

     

Hamstring tendon autograft versus fresh-frozen tibialis posterior allograft in primary arthroscopic anterior cruciate ligament reconstruction: a retrospective cohort study with three to six years follow-up

Introduction

Selection of various grafts for anterior cruciate ligament (ACL) reconstructions have been employed in order to improve on stability and function of the knee. This study aimed to compare stability and function of the knee after ACL arthroscopic reconstruction by single-loop tibialis posterior (TP) allograft and four-strand hamstring tendon (HT) autograft.

Materials and methods

The retrospective cohort study included 104 patients in the TP group matched with 118 patients in the HT group in terms of demographic characteristics, associated meniscus injury, subjective and objective knee characteristics. All patients were followed up for at least three years with regards to mentioned criteria and time of return to former activities.

Results

The mean (range) age of TP (88 males and 16 females) and HT (99 males and 19 females) groups was 34.4 (19–48) and 36.9 (20–51) years, respectively. Median (range) follow-up durations were 55 (37–71) and 56 (36–72) months, respectively. No significant differences were observed post-operatively, regarding subjective and objective evaluations. Additionally, time duration for return to former activity was similar in both groups. Post-operative paresthesia and numbness of medial aspect of the calf were observed for two months in eight patients of the HT group which persisted to the final visit in one case. No similar symptom was seen in the TP group.

Conclusion

In arthroscopic ACL reconstruction, fresh frozen doubled TP allograft compared to HT autograft was equally effective in restoring function and stability of knee, permitting return to former activities.

Level of evidence

Retrospective comparative, Level III

     

Mechanisms and situations of anterior cruciate ligament injuries in professional male soccer players: a YouTube-based video analysis

Background

Soccer is considered the most popular sport in the world concerning both audience and athlete participation, and the incidence of ACL injury in this sport is high. The understanding of injury situations and mechanisms could be useful as substratum for preventive actions.

Purpose

To conduct a video analysis evaluating the situations and mechanisms of ACL injury in a homogeneous population of professional male soccer players, through a search entirely performed on the YouTube.com Web site focusing on the most recent years.

Methods

A video analysis was conducted obtaining videos of ACL injury in professional male soccer players from the Web site YouTube. Details regarding injured players, events and situations were obtained. The mechanism of injury was defined on the basis of the action, duel type, contact or non-contact injury, and on the hip, knee and foot position.

Results

Thirty-four videos were analyzed, mostly from the 2014–2015 season. Injuries occurred mostly in the first 9 min of the match (26%), in the penalty area (32%) or near the side-lines (44%), and in non-rainy conditions (97%). Non-contact injuries occurred in 44% of cases, while indirect injuries occurred in 65%, mostly during pressing, dribbling or tackling. The most recurrent mechanism was with an abducted and flexed hip, with knee at first degrees of flexion and under valgus stress.

Conclusions

Through a YouTube-based video analysis, it was possible to delineate recurrent temporal, spatial and mechanical characteristics of ACL injury in male professional soccer players.

Level of evidence

Level IV, case series.

     

Quantitative correlation of mechanoreceptors in tibial remnant of ruptured human anterior cruciate ligament with duration of injury and its significance: an immunohistochemistry-based observational study

Background

Proprioception is a specialized sensory modality encompassing the movement of the joint and its position in space. Reconstruction of the anterior cruciate ligament (ACL) does not always yield expected outcome, suggesting that successful reconstruction depends on not only the ultimate strength of the graft but also recovery of proprioception. Treatment delay is a significant concern in developing countries, e.g., in Asia. Thus, presence of mechanoreceptors is one of the factors having paramount importance for successful outcome. We conducted this study to identify mechanoreceptors via immunohistochemical staining and correlate their presence with duration of injury.

Materials and methods

A total of 38 injured native ACL stumps were harvested from patients undergoing ACL reconstruction and stained with neurofilament protein stain to detect functional mechanoreceptors.

Results

Of the specimens, 44.7% stained positive for monoclonal antibody. No association was found between duration of injury and presence of mechanoreceptors (p = 0.897). No correlation was seen between age and side.

Conclusions

No correlation was found between duration of injury and presence of viable mechanoreceptors, hence it is beneficial to preserve the native ACL stump irrespective of the time interval between injury and surgery.

Level of Evidence

III.

     

Verletzungen des vorderen Kreuzbandes und posturale Kontrolle

Background

Quantification of postural stability deficits after anterior cruciate ligament (ACL) rupture requires a complex measurement process, the so-called computerized dynamic posturography (CDP). It would be desirable if the decrease in postural stability caused by ACL rupture could be estimated by simpler functional scores. The aim of this study was therefore to review the currently available standard knee scores for the suitability to assess postural stability.

Patients and methods

In this study 58 patients with isolated unilateral ACL rupture were examined using CDP. The questionnaires used were Tegner, WOMAC, ADL-KOS, KOS-Sport, KSS and Lysholm scores. The values obtained were compared and correlated with the results of the CDP. In addition, a subgroup analysis of copers and non-copers was performed.

Results

There was no significant correlation with the postural stability deficit for any of the scores examined in this study. Only the subjectively perceived instability correlated appreciably with the CDP with r=0.423.

Conclusions

All currently used scores for the investigation of patients with ACL rupture cannot give any information about the ability of postural balance. If patients complain about an increased subjective feeling of instability a close observation of postural stability using CDP is inevitable.

     

Effects on proprioception by Kinesio taping of the knee after anterior cruciate ligament rupture

Introduction

The use of Kinesio tape (KT) to improve proprioception is a matter of considerable debate. In comparison, the rupture of the anterior cruciate ligament is a sufficiently well-investigated injury with a proven compromise of proprioception. The objective of the present study was to assess a supportive effect on proprioception after KT application, taking the anterior cruciate ligament (ACL) rupture as an example.

Materials and methods

Forty-eight patients who had suffered an ACL rupture, confirmed clinically and by magnetic resonance imaging, and who were treated conservatively or were awaiting surgery were included in this study. In all patients, a gait analysis was performed on the affected leg before and after KT application. In addition, the IKDC score, the Lysholm score, stability using the Rolimeter, and the angle reproduction test were determined.

Results

Thirty-nine men and nine women who had had an ACL rupture for at least 3 weeks were included in the study. Significant improvements were achieved on the affected knee joint for the gait analysis parameters touchdown and unrolling, cadence, stability and stance phase as well as an extension of the hip joint. The Lysholm score improved from 79.3 to 85.8 (p?<?0.001) and the IKDC score from 60.2 to 71.3 points (p?<?0.001). Significant improvements were achieved in the Rolimeter and angle reproduction test.

Conclusions

The use of KT has a positive effect on proprioception in patients with an anterior cruciate ligament rupture. Therefore, the application may improve gait pattern as well as the subjective function of the affected knee joint.

     

Patient and Surgeon Expectations Prior to Anterior Cruciate Ligament Reconstruction

Background

When discussing potential treatment with patients choosing to undergo surgery for disruption of the anterior cruciate ligament (ACL) and their families, surgeons spend considerable time discussing expectations of the short- and long-term health of the knee. Most of the research examining patient expectations in orthopedic surgery has focused largely on arthroplasty.

Questions/Purposes

The purpose of this study was to quantitatively assess the differences between the patient’s and the surgeon’s expectations before primary anterior cruciate ligament reconstruction (ACLR).

Methods

In this case series, we prospectively enrolled 93 patients scheduled for primary ACLR between 2011 and 2014. Expectations were measured using the Hospital for Special Surgery 23-item Knee Expectations Survey; scores were calculated for each subject.

Results

In all but six categories, patients had expectations that either aligned with their surgeons’ or were lower. The largest discordance between surgeon and patient expectations in which the patient had lower expectations was employment; 75% of patients had similar expectations to the surgeon when asked if the knee would be “back to the way it was before the problem started,” less than 1% had higher expectations, and 17% had lower expectations.

Conclusion

In general, patient expectations align well with surgeon expectations. Patients who are older, have a lower activity level, and who have selected allograft over autograft for ACLR could also be at risk for greater discordance. Understanding these differences, and their predictors, will help guide physicians when they are counseling patients about ACLR and also help them interact with patients after surgery as they assess outcomes.

     

Effect of high and low-supportive footwear on female tri-planar knee moments during single limb landing

Background

Higher landing-related external knee joint moments at later stages of female pubertal development likely contribute to a higher incidence of non-contact anterior cruciate ligament (ACL) injury. Athletic footwear may provide a potential strategy to alter higher knee moments.

Methods

Thirty-one late/post-pubertal girls (Tanner stage IV-V, menarche and growth spurt attained) performed a single limb drop lateral jump in three footwear conditions (barefoot, low support shoes and high support shoes), in which peak knee abduction moment (KAbM), flexion moment (KFM) and internal rotation moments (KIRM) were measured. Repeated measures ANOVA and ANCOVA were used to test for a main effect of footwear with and without foot posture index (FPI) as a covariate (p?<?0.05) with post-hoc test carried out via Fisher’s Least Significant Difference (LSD).

Results

A main effect of footwear condition was observed for peak KFM (p <?0.05), but not KAbM or KIRM, in both unadjusted and adjusted models. Post-hoc analysis demonstrated that both high- and low-support shoes increased peak KFM compared with barefoot (p?<?0.001).

Conclusion

Our findings indicate commercially available high- and low-supportive footwear increase peak KFM, but do not effect KAbM or KIRM while landing among late/post-pubertal girls. This suggests that these styles of footwear are inadequate at reducing higher knee moments in an at-risk cohort.

     

Does the hyperextension maneuver prevent knee extension loss after arthroscopic anterior cruciate ligament reconstruction?

Background

Disruption of the anterior cruciate ligament (ACL) is one of the most frequent musculoskeletal injuries affecting physically active men and women. In the United States, an estimated 200,000 ACL reconstructions are performed annually. One of the most common complications of ACL reconstruction is loss of extension. The purpose of this study was to assess the effects of the hyperextension maneuver on preventing knee extension loss after arthroscopic ACL reconstruction.

Materials and methods

In this prospective randomized clinical trial study, 100 adult patients with a documented complete ACL tear were randomized to two groups. All patients underwent arthroscopic ACL reconstruction with quadrupled semitendinosus and gracilis autograft by the senior author based on the same technique and instruments. However, the hyperextension maneuver was only performed in 50 patients during autograft fixation on the tibial side (case group). The postoperative rehabilitation protocol was similar for both groups. The knee range of motion and extension limit was evaluated at 2, 6, 12, and 24 weeks and at 1 year postoperatively.

Results

One hundred patients (88 male and 12 female) aged from 17?36 years (average 26.9 years) were included in our study. The two groups were similar regarding age, sex, and dominant side involvement (P >0.4).The difference between the two groups was significant only at 2 weeks (P <0.02). After 2 weeks, although the rate of limited extension was higher in the control group, no significant difference was seen between the groups.

Conclusion

Although the hyperextension technique during graft fixation on the tibial side may induce better range of motion in the first 2 weeks after ACL reconstruction surgery, this effect is not significant after 2 weeks.

Level of evidence

Therapeutic level II.

     

Patient-based decision for resuming activity after ACL reconstruction: a single-centre experience

Purpose

The purpose of the study was to report the functional outcome following anterior cruciate ligament (ACL) reconstruction in patients who decide when to resume work and normal sporting activity post-operatively. The hypothesis tested was that patient-based decision to return to work and sport was possible without compromising functional outcome and increased the rate of repeat rupture in comparison with the existing literature.

Methods

This was a monocentric, retrospective study. Seventy-two patients requiring primary ACL reconstruction were included. All patients were followed up for a mean period of 4.3 years. Return to work and to sporting activity was allowed based on patient’s decision. No restriction was suggested by the physician. Delays to return to work and sports and occurrence of graft failure were documented.

Results

Sixty-six patients (92 %) returned to any sporting activity. The mean delay was 4.1 months for running, 6.1 months for pivoting sports, and 6.6 months for contact sports. Return to competitive sport was possible in 82 % of patients after a mean delay of 7.1 months. Return to work was possible for 96 % of patients after a mean delay of 2.3 months. Index Tegner score normalized in 71 % of patients. Four repeat ruptures (6 %) were observed, all of them following a significant knee injury.

Conclusions

Patient-based decision to return to work and sport was possible without compromising functional outcome. The post-operative restrictions implemented by orthopaedic surgeons following ACL reconstructions may be relaxed and more patient based.

     

High Interspecimen Variability in Engagement of the Anterolateral Ligament: An In Vitro Cadaveric Study

Background

Anterolateral ligament (ALL) reconstruction as an adjunct to anterior cruciate ligament (ACL) reconstruction remains a subject of clinical debate. This uncertainty may be driven in part by a lack of knowledge regarding where, within the range of knee motion, the ALL begins to carry force (engages).

Questions/purposes

(1) Does the ALL engage in the ACL-intact knee; and (2) where within the range of anterior tibial translation occurring in the ACL-sectioned knee does the ALL engage?

Methods

A robotic manipulator was used to measure anterior tibial translation, ACL forces, and ALL forces in 10 fresh-frozen cadaveric knees (10 donors; mean age, 41 ± 16 years; range, 20-64 years; eight male) in response to applied multiplanar torques. The engagement point of the ALL was defined as the anterior tibial translation at which the ALL began to carry at least 15% of the force carried by the native ACL; a threshold of 15% minimized the sensitivity of the engagement point of the ALL. This engagement point was compared with the maximum anterior tibial translation permitted in the ACL-intact condition using a paired Wilcoxon signed-rank test (p < 0.05). Normality of each outcome measure was confirmed using Kolmogorov-Smirnov tests (p < 0.05).

Results

The ALL engaged in five and four of 10 ACL-intact knees in response to multiplanar torques at 15° and 30° of flexion, respectively. Among the nine of 10 knees in which the ALL engaged with the ACL sectioned, the ACL-intact motion limit, and ALL engagement point, respectively, averaged 1.5 ± 1.1 mm and 5.4 ± 4.1 mm at 15° of flexion and 2.0 ± 1.3 mm and 5.7 ± 2.7 mm at 30° of flexion. Thus, the ALL engaged 3.8 ± 3.1 mm (95% confidence interval [CI], 1.4-6.3 mm; p = 0.027) and 3.7 ± 2.4 mm (95% CI, 2.1-5.3 mm; p = 0.008) beyond the maximum anterior tibial translation of the ACL-intact knee at 15° and 30° of flexion, respectively.

Conclusions

In this in vitro, cadaveric study, the ALL engaged in up to half of the ACL-intact knees. In the ACL-sectioned knees, the ALL engaged beyond the ACL-intact limit of anterior subluxation on average in response to multiplanar torques, albeit with variability that likely reflects interspecimen heterogeneity in ALL anatomy.

Clinical Relevance

The findings suggest that surgical variables such as the joint position and tension at which lateral extraarticular grafts and tenodeses are fixed might be able to be tuned to control where within the range of knee motion the graft tissue is engaged to restrain joint motion on a patient-specific basis.

     

Segond’s fracture: a biomechanical cadaveric study using navigation

Background

Segond’s fracture is a well-recognised radiological sign of an anterior cruciate ligament (ACL) tear. While previous studies evaluated the role of the anterolateral ligament (ALL) and complex injuries on rotational stability of the knee, there are no studies on the biomechanical effect of Segond’s fracture in an ACL deficient knee. The aim of this study was to evaluate the effect of a Segond’s fracture on knee rotation stability as evaluated by a navigation system in an ACL deficient knee.

Materials and methods

Three different conditions were tested on seven knee specimens: intact knee, ACL deficient knee and ACL deficient knee with Segond’s fracture. Static and dynamic measurements of anterior tibial translation (ATT) and axial tibial rotation (ATR) were recorded by the navigation system (2.2 OrthoPilot ACL navigation system B. Braun Aesculap, Tuttlingen, Germany).

Results

Static measurements at 30° showed that the mean ATT at 30° of knee flexion was 5.1 ± 2.7 mm in the ACL intact condition, 14.3 ± 3.1 mm after ACL cut (P = 0.005), and 15.2 ± 3.6 mm after Segond’s fracture (P = 0.08). The mean ATR at 30° of knee flexion was 20.7° ± 4.8° in the ACL intact condition, 26.9° ± 4.1° in the ACL deficient knee (P > 0.05) and 30.9° ± 3.8° after Segond’s fracture (P = 0.005). Dynamic measurements during the pivot-shift showed that the mean ATT was 7.2 ± 2.7 mm in the intact knee, 9.1 ± 3.3 mm in the ACL deficient knee(P = 0.04) and 9.7 ± 4.3 mm in the ACL deficient knee with Segond’s fracture (P = 0.07). The mean ATR was 9.6° ± 1.8° in the intact knee, 12.3° ± 2.3° in the ACL deficient knee (P > 0.05) and 19.1° ± 3.1° in the ACL deficient knee with Segond’s lesion (P = 0.016).

Conclusion

An isolated lesion of the ACL only affects ATT during static and dynamic measurements, while the addition of Segond’s fracture has a significant effect on ATR in both static and dynamic execution of the pivot-shift test, as evaluated with the aid of navigation.

     

Patellaformen

Background

Patella height is discussed as a possible factor in the development of osteoarthritis of the knee.

Methods

PubMed literature search

Results

Contradictory results are found in the literature.

Conclusion

According to the literature, there is currently no evidence that abnormal patella height can induce osteoarthritis of the knee.

     

Effects of Abduction Pillows on Rotator Cuff Repair: A Biomechanical Analysis

Background

After rotator cuff repair, some surgeons use abduction pillows to unload or protect the repair construct, while others do not.

Question/Purpose

The aim of this study was to determine which type of sling—one with a small or large abduction pillow or one without a pillow—places the repaired rotator cuff in the best position to reduce tension on the supraspinatus.

Methods

An X-ray study was performed on asymptomatic subjects to determine what position the shoulder is placed in when wearing a sling with or without an abduction pillow. Positions were then reproduced in human cadaveric shoulders using a custom-made testing jig, and tension on the repaired supraspinatus was measured.

Results

X-rays showed that abduction of the glenohumeral joint with a sling was only 4°, with a sling with a small pillow was 13°, and with a sling with a large abduction pillow was 25°. Placing the cadaveric shoulders in the position of a sling with a small abduction pillow caused a reduction in tension on the supraspinatus of 27% anteriorly and 55% posteriorly compared to placing the shoulder in the position of a sling without an abduction pillow; a large abduction pillow caused a further reduction in tension, of 42% anteriorly and 56% posteriorly.

Conclusion

These findings show that abduction pillows reduce tension on the repaired supraspinatus tendon.