Henrik Behrend

Association of psychological status and patient-reported physical outcome measures in joint arthroplasty: a lack of divergent validity.

BackgroundPatient-reported outcome measures have become a well-recognised part of outcome assessment in orthopaedic surgery. These questionnaires claim to measure joint-specific dimensions like pain, function in activities of daily living, joint awareness or stiffness. Interference of the patient’s psychological status with these orthopaedic questionnaires however may make accurate interpretation difficult.MethodsWe recruited 356 patients after unilateral, primary THA or TKA and performed a postal survey including the Brief Symptom Inventory (psychological distress measure), the Catastrophising Scale (from the Coping Strategies Questionnaire), the WOMAC score (Western Ontario and McMaster Universities Osteoarthritis Index) and the Forgotten Joint Score – 12 (FJS-12). Associations between the different questionnaires were determined calculating Pearson correlation coefficients. Two multiple linear regression models were used to investigate the impact of socio-demographic variables, clinical variables and of the psychological scales (BSI and Catastrophising Scale) separately for the WOMAC score and the FJS-12.ResultsWOMAC-Total score showed strong correlation to Catastrophising (r = 0.79), BSI-Somatisation (r = 0.63) and BSI-GSI (r = 0.54). The FJS-12 demonstrated modest to strong correlation with Catastrophising (r = −0.60), BSI-Somatisation (r = −0.49) and the BSI-GSI (Global Severity Index) (r = −0.44). BSI-GSI and Catastrophising explained 54.3% of variance in a multivariate regression model for the WOMAC score. The same two scales explained 30.0% of variance for the FJS-12.ConclusionsThere is a strong relationship between psychological status and orthopaedic outcome. The scale names of orthopaedic outcome measures suggest to measure specific dimensions like pain, stiffness, function or joint awareness. In fact they largely include patient’s psychological status indicating poor divergent validity.

WOMAC, EQ-5D and Knee Society Score Thresholds for Treatment Success After Total Knee Arthroplasty

Our study aimed at developing clinical thresholds (cut-off scores) for the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, EQ-5D and Knee Society Score for discriminating between patients with and without treatment success following total knee arthroplasty (TKA). We performed a retrospective analysis of 1055 patients 2 months after TKA and 765 patients 1 year after TKA. We considered treatment successful if the patient reported high levels of satisfaction and pain relief, functional increase, and a willingness to undergo the same procedure again. Based on this criterion we identified cut-off scores that will facilitate interpretation of the WOMAC, the EQ-5D and the KSS in TKA patients.

Joint awareness after ACL reconstruction: patient-reported outcomes measured with the Forgotten Joint Score-12

PurposeTo measure joint awareness in patients who have undergone anterior cruciate ligament (ACL) reconstruction and to investigate medium- and long-term results of the procedure.MethodsAll patients who had undergone ACL reconstruction with the same arthroscopic surgical technique at our institution between 2011 and 2014 (medium-term follow-up group (Group I)) or between 2000 and 2005 (long-term follow-up group (Group II)) were considered for inclusion in the study. A group of healthy controls were recruited to obtain reference values for the FJS-12 (Forgotten Joint Score-12). Propensity score matching was applied to improve comparability of patients and healthy controls in terms of sex and age.ResultsFifty-eight patients of the Group I (mean follow-up 31.5 (SD13.4) months, range 12–54), 57 patients of the Group II (mean follow-up 139 (SD15.2) months, range 120–179), and the healthy control samples (100 individuals) were analysed. Significantly lower FJS-12 was found in both groups (Group I: 71.6 and Group II: 70.1), compared to the two matched control groups (88.1 and 90.0).ConclusionsThe concept of joint awareness was successfully applied to evaluate medium- and long-term results of ACL reconstruction. The clinical relevance of this study is that it extends the construct of joint awareness as a patient-reported outcome parameter to ACL reconstruction surgery.Level of evidenceLevel III.

Joint Mechanics After Total Knee Arthroplasty While Descending Stairs

BACKGROUND Modern knee designs do not fully restore the anatomy and kinematics of the natural knee. This study evaluates the kinematic and kinetic changes of well-functioning patients with total knee arthroplasty (TKA) in comparison to a healthy age-matched control group while descending stairs and level walking. The aim was to have a baseline for further investigations of TKA patients with problems. METHODS Fifteen patients satisfied with TKA (8♀/7♂; 66.8 ± 7.4 years; body mass index (BMI) 25.9 ± 2.8 kg/m2; 2.1 ± 1.3 years postop, LCS Complete) and 17 healthy control subjects (7♀/10♂; 66.6 ± 6.8 years; BMI 25.0 ± 2.2 kg/m2) participated in the study. Kinematic (upper and lower body) and kinetic (lower body) data were collected during stair descending (step height 17 cm) and level walking, using an 8-camera Vicon system and 2 force plates. Parameters were compared using a Student t test. RESULTS Patients after TKA showed significantly lower frontal knee moments and a more externally rotated hip during stance for both level walking and stair descent. There were 31% more significantly different parameters during level walking than during stair descent. CONCLUSION The analysis of stair descending in addition to level walking for satisfied patients does not add additional information for the understanding of the kinematic and kinetic changes after TKA. It seems more important to include the kinematics and kinetics of the hip and ankle joint in all 3-dimensional planes.

Complete rupture of the popliteal artery complicating high tibial osteotomy.

We present two cases of high tibial osteotomies performed at our institution. Both cases were complicated with the immediate postoperative occurrence of an ischaemic syndrome of the lower leg. Urgent diagnostics revealed a complete rupture of the popliteal artery that required re-operation and a vascular repair. Although neurovascular complications during high tibial osteotomies are rare the awareness of this potentially catastrophic complication should be present when performing this common procedure. All precautions to minimize the harm to the neurovascular bundle should be put into practice. A summary of the surgical precautions is presented and discussed in this paper.

Improvement of primary stability in ACL reconstruction by mesh augmentation of an established method of free tendon graft fixation. A biomechanical study on a porcine model

PURPOSE The aim of the present study was to compare primary stability in ACL reconstruction and ultimate load to failure of a mesh augmented hamstring tendon graft fixed with two cross pins to established hamstrings and bone-patellar-tendon-bone (BTB) graft fixation methods. METHODS Forty fresh porcine femora were divided into four groups: (A): BTB graft fixed with two RigidFix® pins, (B): hamstring tendon graft fixed with a Milagro® interference screw, (C): hamstring tendon graft fixed with two RigidFix® pins, and (D): hamstring tendon graft augmented with Ultrapro® mesh fixed with two RigidFix® pins. Each graft underwent cyclic loading in tension and load to failure. Elastic and plastic displacements were measured by 3-dimensional digital image correlation. Groups were compared by one-way ANOVA and Tukey-Kramer post-hoc tests. RESULTS After 1000 cycles, the mean plastic displacement was lowest in the BTB graft (p < 0.001). Plastic displacement was significantly lower in the mesh augmented group compared to the plain hamstring graft and the Milagro screw group (p < 0.05). Load to failure was highest in the mesh-augmented group; significant to the hamstring tendon (p = 0.023). CONCLUSION Although the BTB-graft represented the most stable construct against plastic displacement in our study, mesh augmentation of free tendon grafts significantly increased primary stability and reduced plastic displacement of femoral cross pin fixation. This new augmentation device may better protect the hamstrings graft from secondary elongation during postoperative rehabilitation. CLINICAL RELEVANCE Mesh augmentation seems to be an effective technique to stabilise free hamstring tendon autografts during postoperative rehabilitation with significant reduction of graft slippage.

Whole Body Gait Function during Stair Ascending and Level Walking in Patients Following Total Knee Arthroplasty

The ability to climb stairs is a highly demanding task for the musculoskeletal system, and gait adaptations after total knee arthroplasty (TKA) might be more pronounced during stair climbing than during level walking. The purpose of this study was to compare full body kinematics and kinetics between patients with good functioning TKA and a healthy control group during stair ascending and level walking. Eighteen patients after TKA (67.8 ± 8.1 yrs) and 20 age-matched healthy controls (66.1 ± 6.4 yrs) participated in this study. Full body kinematic and kinetic data was collected during stair ascending and level walking. Patients after TKA showed differences in sagittal plane knee moments during both stair ascending and level walking compared to the controls. The hip of the patients was more externally rotated in both conditions (p<0.001), although there were no differences in the passive range of motion (p=0.630). The trunk angles only showed a few deviations between patients and controls. Differences between patients and controls were found more often during level walking than during stair ascending. The study shows that considering adjacent joints gives more additional information for treatment recommendations than the additional analysis of the trunk when comparing patients after TKA to healthy seniors. To reduce the higher knee flexion moment during stair ascending in patients, we recommend the strengthening of the calf muscles. It seems that stair ascending does not provide additional information to guide actual treatment recommendations compared to level walking alone.

Functional knee phenotypes: a call for a more personalised and individualised approach to total knee arthroplasty?

Total knee arthroplasty (TKA) has made major advancements in the past. Landmark steps for improved outcome after TKA were advanced surgical techniques, standardised instrumentation, development of durable material and improved patient care pathways. However, still 20–30% of patients are not pain free or satisfied after TKA [3]. As expert knee surgeons, we need to ask the question why there is still such a considerable percentage of unhappy patients after TKA. Much effort has already been put into this question by many research groups. For a long time, a neutral mechanical alignment appeared to be the solution for each knee [5]. Just recently many authors questioned the necessity of neutral mechanical alignment [6, 7]. Bellemans et al. proposed the concept of constitutional alignment for varus knees [1]. Anatomic alignment and kinematic alignment were introduced or reinvented as systematic alignment methods [4]. However, the major problem here is the systematic approach. A systematic approach is based on the theory of a systematic solution for the problem. However, this approach is too simplified. It does not sufficiently consider anatomical variability of each knee. When you treat every knee the same, there will be happy and unhappy knees as some will be in the envelope of function and some will not. Sadly, systematic alignment considerations are not the holy grail of TKA. Clearly, one of the major misconceptions of TKA nowadays still is that the variability and individuality of each knee are not sufficiently considered in conventional TKA. Neither with regards to alignment nor to morphology, laxity and function. Although there is a focus on personalised medicine in research nowadays, our knowledge about the variability of each knee is still scarce. The godfathers of knee surgery such as Werner Müller taught us that nothing is so constant as the variability of anatomy [2]. He further told us that a profound understanding of the individuality of each knee is crucial for optimal restoration of the injured knee in reconstructive knee surgery [2]. Clearly, this is also true for knee arthroplasty. It is time to make some steps backwards and meticulously analyse the native and degenerative knee alignment and individual morphology. Due to the improved 3D-CT technology as well as available software, it is the right time to do it [7, 8]. This issue of KSSTA contains a number of scientific articles dealing with the question how to improve outcomes * Michael T. Hirschmann Michael.Hirschmann@unibas.ch

Validating the forgotten joint score-12 in patients after ACL reconstruction

BACKGROUND The forgotten joint score-12 (FJS-12), used to measure postoperative joint awareness, has been extensively validated to assess outcomes after arthroplasty, however the new score has never been validated in evaluating anterior cruciate ligament (ACL) reconstruction. The purpose of our study was to validate the FJS-12 versus the knee injury and osteoarthritis outcome score (KOOS) for patients who have undergone ACL reconstruction. METHODS All patients who had undergone ACL reconstruction with the same arthroscopic surgical technique at our institution between 2011 and 2014 (medium-term follow-up group (M-FU)) or between 2000 and 2005 (long-term follow-up group (L-FU)) were considered for inclusion in the study. To analyze unidimensionality of the FJS-12, we calculated Cronbachs alpha, item-total correlations and conducted an exploratory principal component factor analysis. To assess convergent validity, we calculated Spearman correlation coefficients for the FJS-12 and its comparable scales. RESULTS We analyzed 58 patients of the M-FU (mean follow-up 31.5 (SD13.4) months, range 12-54), and 58 patients of the L-FU (mean follow-up 139 (SD15.2) months, range 120-179). The FJS-12 showed high internal consistency (Cronbachs alpha=0.95). Ceiling effects were considerably lower for the FJS-12 (M-FU 12.1%, L-FU 15.5%) compared with the KOOS subscales (M-FU 5.2-37.9%; L-FU 13.8-55.2%) and WOMAC subscales (M-FU 37.9-62.1%; L-FU 44.8-60.3%). CONCLUSIONS The FJS-12 is a valid measurement tool to evaluate outcomes of ACL reconstruction. This study extends the possibilities of measuring joint awareness as a patient-reported outcome parameter from joint arthroplasty to ACL reconstruction.