INTRODUCTION

Accurate knowledge of knee joint kinematics following total knee arthroplasty (TKA) is critical for evaluating the functional performance of specific implant designs. Biplane fluoroscopy is currently the most accurate method for measuring 3D knee joint kinematics in vivo during daily activities such as walking. However, the relatively small imaging field of these systems has limited measurement of knee kinematics to only a portion of the gait cycle. We developed a mobile biplane X-ray (MoBiX) fluoroscopy system that enables concurrent tracking and imaging of the knee joint for multiple cycles of overground gait. The primary aim of the present study was to measure 6-degree-of-freedom (6-DOF) knee joint kinematics for one complete cycle of overground walking. A secondary aim was to quantify the position of the knee joint centre of rotation (COR) in the transverse plane during TKA gait.

ACL reconstruction is successful in restoring sagittal stability of the knee but has been less consistent in restoring rotational stability. Increasing coronal graft obliquity improves rotational constraint of the knee in cadaveric biomechanical models. The purpose of this study was to determine whether there is a correlation between coronal graft alignment and tibial rotation during straight line activities.

Seventy-four patients who had undergone ACL reconstruction using a transtibial technique were evaluated. They came from three distinct time periods during which the operating surgeon had deliberately changed the position of the femoral tunnel to progressively achieve a more oblique graft alignment in the coronal plane. Post-operative radiographs were analyzed for the coronal graft orientation and femoral and tibial tunnel positions. Tibial rotation was measured during level walking (n=74) and single-limb landing (n=42) tasks using a motion analysis system. Radiographic measurements of graft and tunnel orientation were correlated with rotational excursion of the knee recorded during these tasks. No correlations were found between knee rotational excursion and either the coronal tibial tunnel angle or the coronal graft angle during level walking. For the single-limb landing task, a significant negative correlation was observed between the coronal angle of the tibial tunnel and rotational excursion (r=−0.3, p=0.05) i.e. increasing tunnel obliquity was associated with decreasing rotational excursion. For the coronal angle of the ACL graft, the correlation was also negative, but was not significant (r=−0.24, p=0.12).

Increases in graft obliquity in the coronal plane were associated with reduced tibial rotational excursions during single limb landing. These findings support the notion that ACL graft orientation may play a role in rotational kinematics of the ACL reconstructed knee, particularly during higher impact activities.

Most people have not returned to their pre-injury level of sports participation 12 months following anterior cruciate ligament (ACL) reconstruction surgery. Twelve months may be too early to assess return to sport outcomes accurately. The purpose of this study was to evaluate the mid-term return to sport outcomes following ACL reconstruction surgery.

A self-report questionnaire was used to collect data from people at 2 to 7 years following ACL reconstruction surgery regarding pre-injury sports participation, post-operative sports participation and subjective knee function. The main inclusion criteria were participation in regular sports activity prior to surgery and the attendance of routine surgical follow up appointments.

A total of 314 people were included at a mean 39.6 ± 13.8 months following ACL reconstruction surgery. At follow up, 45% of people were playing sport at their pre-injury level and 29% were playing competitive sport. Of those playing competitive sport prior to injury, 46% were playing competitive sport at follow up. Ninety three percent of people had attempted sport at some time following their ACL reconstruction surgery. People who had not attempted their pre-injury level of sport by 12 months following surgery were just as likely to have returned to pre-injury level by 39 months after surgery as those who had played sport by 12 months (risk ratio, 95% CI = 1.1, 0.76–1.6).

Less than 50% of people had returned to either their pre-injury level of sport or competitive sport when surveyed at 2 to 7 years following ACL reconstruction surgery. Sporting activity at 12 months was not predictive of participation at 2 to 7 years, suggesting that people who return to sport within 12 months may not maintain their sports participation.

Increased knee flexion is seen as a primary goal in achieving a better functional outcome following TKR. However, the relationship between passive knee flexion and biomechanical outcome remains unclear. The aim of this study was to compare kinematic outcomes in TKR patients and controls during high flexion activities.

A three dimensional motion analysis system and two force platforms were used to collect kinematic and kinetic data from 40 patients who had undergone total knee replacement at least 12 months previously and 40 controls who were matched to the patients for age and gender. Participants completed the following activities six times: standing from a seated position, squatting, and lunging with each leg leading. Peak knee flexion angles and moments were compared between groups using t-tests and the correlations between passive knee flexion and functional knee flexion were calculated using ‘Pearson's r’.

For both squatting and lunging, peak knee flexion in the TKR group was significantly less than in the control group. There was no difference between the two groups for the sit to stand activity as peak flexion for this activity was primarily determined by the chair height.

Squat: control 124, TKR 91 (p<0.001) Lunge - op. forward: control 100, TKR 81 (p<0.001) Lunge - op. trail: control 106, TKR 84 (p<0.001) Sit to stand: control 87, TKR 85 (p=0.5)

Although there were significant correlations between functional and passive knee flexion in the TKR group for the squatting and lunging activities, the patients used only approximately 70 to 75% of their available flexion during these activities. As anticipated, there was only a weak correlation between passive and functional flexion for the sit to stand activity.

Percentage of passive flexion used: squat: 77%, lunge - op. forward: 68%, lunge - op. trail: 70% Sit to stand: 71%, Correlations: squat: 0.50, lunge - op. forward: 0.57, lunge - op. trail: 0.50, Sit to stand: 0.27

Normal sagittal knee kinematics during high flexion activities was not restored following TKR. Patients did not or were unable to use their available range of flexion to achieve a normal kinematic pattern. The cause of this important functional deficit remains to be established but may be amenable to targeted rehabilitation.

High tibial osteotomy (HTO) is an established treatment for medial compartment osteoarthritis of the knee; the aim being to achieve a somewhat valgus coronal alignment, thereby unloading the affected medial compartment. This study investigated knee kinematics and kinetics before and after HTO and compared them with matched control data.

A three dimensional motion analysis system and two force platforms were used to collect kinematic and kinetic data from eight patients with medial compartment knee osteoarthritis during walking preoperatively and 12 months following HTO (opening wedge). Nine control participants of similar age and the same sex were tested using the same protocol. Sagittal and coronal knee angles and moments were measured on both the operated and non-operated knees and compared between the two time points and between HTO participants and controls. In addition, preoperative and postoperative radiographic coronal plane alignments were compared in the HTO participants.

The point at which the mechanical axis passed through the knee joint was corrected from a preoperative mean of 10% tibial width from the medial tibial margin to 56% postoperatively. Stride length and walking speed both improved to essentially normal levels (1.57 m and 1.5 m/s) ostoperatively. In the coronal plane the mean peak adduction angle during stance reduced from 14.3° to 5.2° (control: 6.8°). Mean maximum adduction moments were similarly reduced to levels less than in control participants, in keeping with the aim of the surgical procedure: peak adduction moment 1: pre 3.8, post 2.7, control 3.6 peak adduction moment 2: pre 2.5, post 1.7 and control 2.6.

In the sagittal plane, both mean maximum flexion and extension during stance increased postoperatively—extension to greater than in control participants and flexion to almost control levels. The maximum external knee flexor moment during stance also increased to near normal postoperatively.

High tibial osteotomy appears to achieve the intended biomechanical effects in the coronal plane (reduced loading of the medial compartment during stance). At the same time there were improvements in sagittal plane kinematics and kinetics which may reflect a reduction in pain. The net effect was to reduce quadriceps demand.

It has been suggested that excessive tibial rotation during pivoting tasks is not controlled by single bundle ACL reconstruction (ACLR). This may be partly explained by graft orientation in the coronal plane. The purpose of this study was to assess tibial rotation after ACLR with an obliquely placed hamstring graft.

18 patients were evaluated. All patients had undergone a primary ACLR for an isolated ACL injury within 6 months of injury. All had a 4 strand graft, either semi-tendinosus alone (ST) or semitendinosus and gracilis (STGR) – 9 in each group, each with 2 females and 7 males. Follow-up was at least 2 years postoperatively and all patients had made a good functional recovery and returned to their pre-injury sporting activities. Evaluation consisted of IKDC 2000, instrumented laxity testing, and 3D motion analysis to record tibial rotation when subjects descended stairs and pivoted 90 degrees on landing using a similar protocol to one which has previously been reported.

All patients had made an excellent recovery (mean IKDC score 100 for both groups) and there were no significant differences between the ST and STGR subjects for any of the background variables including anterior knee laxity. There were no differences in the maximal tibial rotational angle between the operated (mean: 20°, range: 10°– 27°) and non operated limb (mean: 21°, range: 6°– 42°). There was no significant difference between the graft types (ST: 20°, STGR: 21°). Females had greater tibial rotation on both the operated and non-operated sides compared to males.

Contrary to previous reports, we found restoration of normal tibial rotation during the pivoting task after a single bundle ACLR. The lack of difference between the ST and STGR groups suggests that this restoration of normal tibial rotation is due to static rather than dynamic restraints. We suggest that it probably reflects the more horizontal graft orientation in the coronal plane for patients in the current study compared to that reported in previous studies.

Aim: In order to monitor the developments in anterior cruciate ligament (ACL) reconstruction and clinical outcome, a national clinical database for knee ligament surgery (Danish ACL Registry) was established in 2005. This study presents data for 2 years national production of ACL reconstructions from the Danish ACL registry.

Methods: All clinics performing ACL reconstructions in Denmark reports to the database. The database is divided into surgeon data and patient data. The surgeon reports anamnestic, objective knee laxity and operative data including graft and implant choices. At one year control, complications, reoperations and objective knee laxity are recorded. The patient registers the KOOS knee score and Tegner function score preoperatively and at 1, 5 and 10 years follow-up. A specific set of indicators that define good diagnostic procedures and clinical outcome have been specified.

Results: During the first 24months, more than 5000 knee-ligament reconstructions were registered. 84 % were primary ACL recontruction, 7,7 % were ACL revisions 8,4 %were multiligament reconstructions. 90 % of all departments reported to the database. 71 % of primary ACL reconstruction used hamstring tendon grafts and 21 % used patella tendon graft. Meniscus injuries were treated in 35 % of all patients. 17 % had significant cartilage lesions. Follow-up KOOS scores demonstrated specific differences between primary ACL, revision ACL and multiligament reconstructions.

Conclusion: This study presents epidiomiology and follow-up data a national ACL reconstruction registry. These data will become new international reference materials for outcome measures before and after ACL surgery. The database will enable future monitoring of developments in ACL reconstruction techniques and outcome.

There are many procedures described to address recurrent patellar instability. This study evaluated the clinical and radiological outcome of a cohort of patients who had been treated using an algorithm based on plain radiography and CT findings to select the appropriate surgical procedure.

64 knees in 49 consecutive skeletally mature patients were treated by one surgeon over 4.8 years. They underwent either tibial tuberosity transfer and lateral release (TTT/LR) or lateral release alone (LR) based on their patellar height and tibial tuberosity trochlear groove (TTTG) distance. Of the knees that were reviewed, 33 underwent TTT/LR and 13 LR. 46 knees in 35 patients were evaluated clinically (42 in 32) or by phone (4 in 3) at a minimum of 1 year. Evaluation included the Kujala and IKDC (subjective and objective) scores and 31 knees underwent repeat radiological examination.

There had been one or more further episodes of instability in 6/46 knees (13%). Only one knee had more than one further episode of instability. The rate of further instability was 8% in the LR group and 15% in the TTT/LR group. The mean overall subjective IKDC score was 80 (LR: 85, TTT/LR: 79). The mean overall objective IKDC scores were 79% A and 21% B (LR: 67% A, 33% B; TTT/LR: 83% A, 17% B). The mean overall Kujala score was 88 (LR:86, TTT/LR: 88). Three patients developed a clinically significant haemarthrosis (LR: 2, TTT/LR: 1), one of whom required an arthroscopic washout. The mean postoperative TTTG distance in the TTT/LR group was 8.5mm compared to the mean preoperative value of 16.2mm (p < 0001). However, there was also a mean reduction in the TTTG distance in the non operated knees of 2.6mm, suggesting a clinically relevant measurement error for this variable.

The algorithm resulted in satisfactory outcomes for most patients. However, changes have subsequently been made in an attempt to further improve outcomes. These include using medial patellar glide to assess the requirement for a lateral release, measuring the TTTG distance with the knee extended, lowering the threshold for distal TTT, raising the threshold for medial TTT, and adding medial patellofemoral ligament reconstruction to the surgical options.

Introduction: Some authors have suggested that the results of ACL reconstruction in females using hamstring tendon (HS) autograft are inferior to those using patellar tendon (PT) autograft. The purpose of this study was to compare our results of ACL reconstruction in females using both graft types.

Material and methods: 80 females who had undergone primary ACL reconstruction using either HS (n=48) or PT (n=32) were evaluated at mean 3.7 year follow-up (2.4 – 5.7). The same surgeon carried out all the reconstructions, using Endobutton femoral fixation and interference screw tibial fixation, and the same rapid rehabilitation protocol was followed by all patients. Independent assessment included IKDC 2000, SF-36, and Cincinnati Sports Activity Score (CSAS) and measurements of anterior knee pain (AKP), kneeling pain and anterior knee laxity (KT-1000).

Results: One patient in the PT group sustained a traumatic graft rupture. For the remaining patients there were no significant differences between the two graft types in terms of objective IKDC 2000 or KT-1000. In terms of subjective IKDC the HS group scored significantly higher (PT: 85 pts., HS: 90pts, p< 0.05), as well as for the CSAS (PT:72.8 vs. HS: 82.1, p< 0.01) and for the SF-36 on the Physical Functioning (PT:90 vs. HS:95, p< 0.01) and General Health subscales (PT:79 vs. HS 86, p< 0.05). Although there was no significant difference in AKP between the two groups, there was a significantly greater mean kneeling pain in the PT group (PT:4.1 vs. HS: 2.5, p=0.001).

Conclusions: Both PT and HS primary ACL reconstructions appear to provide comparable good objective results in females, but ACL reconstruction with HS showed significantly better subjective results. This finding seems to be related to less donor site problems compared with PT. Our results indicate that a quadruple hamstring autograft is an adequate alternative to a patellar tendon autograft for ACL reconstruction in female patients.

Introduction and Aims: Some authors have suggested that, in females, the results of ACL reconstruction using hamstring tendon (HS) grafts are inferior to those using patellar tendon (PT) grafts, while others have suggested that HS grafts may be preferable. This study compared the mid-term results of ACL reconstruction in females using both graft types.

Method: Sixty-six females who had undergone primary ACL reconstruction using either HS (n=43) or PT autograft (n=22) were evaluated at a mean 3.7 years follow-up (range 2.6–5.5). All procedures were performed by the same experienced knee surgeon using an arthroscopically assisted, single-incision technique, with Endobutton femoral fixation and interference screw tibial fixation. The same rapid rehabilitation protocol (immediate full extension and weight-bearing; no brace) was used for all patients. Assessment was performed by an independent orthopaedic surgeon and included IKDC 2000, SF-36 and Cincinatti Sports Activity scores and measurements of anterior knee pain (AKP), kneeling pain and anterior knee laxity (KT-1000).

Results: The overall results in both groups were good. One PT patient sustained a traumatic graft rupture. The HS patients had higher Cincinnati Sports Activity Scores (HS: 83 vs. PT: 72, p< 0.05), but there was no difference in IKDC subjective scores (HS: 89.6 vs. PT: 85.7). For the SF-36, the HS group scored significantly higher on Physical Functioning (HS: 95.4 vs. PT: 89.8, p< 0.01) and General Health subscales (HS: 87.5 vs. PT: 78.4, p< 0.05), but there were no differences for the other subscales. Although there was no significant difference in AKP between the two groups (HS: 1.3/10 vs. PT: 1.7), there was a significantly greater mean kneeling pain in the PT group (PT: 4.0/10 vs. HS: 1.3, p< 0.001). There was no difference between the groups in side to side difference in anterior knee laxity at 134N (HS: 1.7mm vs. PT: 1.8mm). Seventy percent HS and 71% PT patients had a difference of < 3mm, with all remaining patients having 3–5mm difference. There was no difference in terms of overall IKDC knee examination grade, but the HS group had a lesser (hyper)extension deficit (HS: 1.0° vs. PT: 1.8°, p< 0.05).

Conclusion: Both PT and HS ACL reconstructions appear to provide satisfactory results in females, but HS grafts are associated with fewer symptoms, a greater return to pre-injury level of activity and higher quality of life scores.

Aim: To determine the short to mid-term outcome differences between patellar tendon (PT) and hamstring (HS) autograft in anterior cruciate ligament (ACL) reconstructions.

Methods: Sixty-five patients undergoing primary ACL reconstruction were randomised to receive either a PT or a quadruple HS autograft. Post operatively patients undertook a standard “accelerated” rehabilitation protocol. Patients were reviewed at four and eight months and then after one, two and three years.

Results: Anterior knee pain was significantly more common in the PT group at eight months, and again at two years, but not at other times. Pain on kneeling was significantly greater in the PT group at four months and this difference persisted at three years. There was a significantly greater incidence of effusion in the PT group at eight months. Extension deficits were significantly greater in the PT group at eight months and this continued unchanged at three years. Active flexion deficits were significantly greater in the hamstring group at one and two years but not at three years.

KT-1000 side to side differences in anterior knee laxity were significantly greater in the HS group from four months through to three years. There were significantly greater peak quadriceps torque deficits in the PT group at four months and at eight months. Sports activity levels were significantly higher in the PT group at four months but this difference had resolved by eight months. Cincinnati scores were significantly higher in the HS group at one year but not thereafter. There was no difference in IKDC ratings between the two groups. Radiographic femoral tunnel widening was significantly more prevalent and greater in the HS but did not correlate with any clinical differences. Radiographic tunnel widening was present at four months and did not change significantly thereafter.

Conclusions: Overall, HS autografts were associated with less morbidity but increased anterior knee laxity and radiographic femoral tunnel widening compared with PT autografts. From a functional point of view, there was no significant difference between the two graft types at three years.