Massimiliano Marcucci

Relationship between Tibial Baseplate Design and Rotational Alignment Landmarks in Primary Total Knee Arthroplasty

This study evaluated the influence of modern tibial baseplate designs when using the anterior tibial cortex as a primary rotational landmark for the tibial baseplate in TKA. Eighty patients undergoing TKA were randomized in two groups. Group 1 included 25 females and 15 males receiving a posterior-stabilized (PS) symmetric tibial baseplate while Group 2 included 24 females and 16 males receiving a PS anatomical tibial component. Identical surgical technique, including the use of the surgical transepicondylar femoral axis (sTEA) and the anterior tibial cortex (“Curve-on-Curve”) as rotational alignment landmarks, was used. All patients underwent CT evaluation performed with the knee in full extension. Three observers independently measured the rotational alignment of the tibial component in relation to the sTEA. The rotational alignment of the symmetric baseplate showed an average external rotation of 1.3° (minimum 5°, maximum −1°): 91% of the knees showed 0 ± 3° with respect to the surgical sTEA, being internally rotated in 20%. The rotational alignment of the anatomical baseplate showed an average external rotation of 4.1° (minimum 0.4°, maximum 8.9°): only 47.5% of the knees showed 0 ± 3°, being externally rotated in 100%. The difference between the two groups was statistically significant. This study confirms the reliability of the “Curve-on-Curve” technique as an adequate rotational alignment anatomical landmark in TKA: the use of an asymmetric tibial baseplate might lead to external rotation of the tibial component when this technique is intraoperatively chosen.

Primary posterior stabilized total knee arthroplasty: analysis of different instrumentation

BackgroundIntercondylar femoral bone removal during posterior stabilized (PS) total knee arthroplasty (TKA) makes many cruciate substituting implant designs less appealing than cruciate retaining implants. Bone stock conservation is considered fundamental in the prevision of future revision surgeries. The purpose of this study was to compare the quantity of intercondylar bone removable during PS housing preparation using three contemporary PS TKA instrumentations.MethodWe compared different box cutting jigs which were utilized for the PS housing of three popular PS knee prostheses. The bone removal area from every PS box cutting jig was three-dimensionally measured.ResultsIndependently from the implant size, the cutting jig for a specific PS TKA always resected significantly less bone than the others: this difference was statistically significant, especially for small- to medium-sized total knee femoral components.ConclusionThis study does not establish a clinical relevance of removing more or less bone at primary TKA, but suggests that if a PS design is indicated, it is preferable to select a model which possibly resects less distal femoral bone.

Rotational alignment of the tibial component in total knee arthroplasty

Many surgical techniques, correlated to different anatomical landmarks, have been proposed to allow a satisfactory rotational alignment of the tibial component in primary total knee arthroplasty (TKA). Unfortunately, an accurate landmark has not yet been established although many computer models using CT reconstructions and standard radiologic studies have been performed. In this review article, the authors propose a new anatomical rotational reference for a correct positioning of the tibial component during primary TKA; the authors compared the results of their studies with the current literature on rotational alignment references and previously proposed surgical techniques. The authors also analyzed the correlation between classic and newer tibial baseplate designs and different tibial rotational landmarks.

The influence of the crutch setup on stability and weight-bearing parameters in post total hip replacement surgery patients during quiet standing

Abstract Purpose: The purpose of this study is to evaluate the influence of the crutch setup on standing, in post total hip replacement (THR) surgery patients. Materials and methods: Thirty patients after THR were randomly assigned to walking with the elbow flexed (EF) or elbow straight (ES) crutch setup. Subjects were asked to stand on a force platform in a comfortable position with the crutch positioned on the unaffected side, facing forward for 10 seconds. Centre of pressure total path and maximal excursion were evaluated in both medio-lateral and anterior–posterior planes. Difference in the asymmetry of left/right acromial height, measured with and without the crutch, was calculated (ACdiff). Percentage of body weight borne by the crutch (Fcr), symmetry (SIload) between operated and healthy limbs loading during the trial, together with shoulder forces and moments were measured. Results: No significant differences between the two groups (p > .05) were found for stability parameters. ACdiff, Fcr and shoulder load increased significantly (p < .05) in EF group compared to ES group. In addition leg loading symmetry was significantly reduced in the EF group. Conclusions: The present study showed that the ES setup reduced the force borne by the crutch, the load on the shoulder joint and it minimized postural and loading asymmetries when compared to EF setup. Conversely, postural stability was not influenced by the crutch setup. Implications for Rehabilitation Static posture and weight-bearing parameters are influenced by crutch setup during quiet standing. Crutch setup does not influence postural stability. Adjusting the crutch according to the elbow straight setup reduces the force borne by the crutch and the asymmetry in lower limbs loading. Forces and moments at the shoulder joint were reduced for the elbow straight setup group.

Does crutch length influence gait parameters after total hip replacement surgery

After total hip replacement surgery, crutches are often prescribed to enable patients to walk independently. Purpose of this study was to evaluate possible crutch length influence on gait performance and symmetry, including spatiotemporal and kinetics parameters. Thirty patients were randomly assigned to elbow flexed (EF) or elbow extended (EE) crutch setup. Subjects were asked to walk on the laboratory path, instrumented with motion tracking system and force platforms. Spatiotemporal gait parameters and ground reaction force (GRF) parameters for both limbs and crutch support were evaluated. In addition, limb symmetry was evaluated for both gait and force parameters using the symmetry index. Variability was quantified for base of support width, stride time and length as the coefficient of variation. Results showed that cadence and walking speed were not significantly different, but stride length significantly decreased and base of support width increased for the EF group when compared to the EE group. Operated limb GRF parameters were significantly decreased for the EF group, while crutch force parameters decreased for the EE group. Furthermore, the EF group showed greater stride length variability and asymmetry of force and spatiotemporal parameters than EE group did. The results of the present study showed that EF and EE setups did not assist patients equally during walking, with EE setup allowing more load bearing on the operated side, reducing load on the crutch and asymmetries in gait parameters when compared to the EF setup. This may help clinicians in rationalizing crutch setup for patients after total hip replacement surgery.

Posterior-stabilized total knee arthroplasty: a matched pair analysis of a classic and its evolutional design

Background Total knee arthroplasty (TKA) designs continue to be modified to optimize patients outcome. This study was designed to compare clinical and radiological results of classic worldwide used TKA posterior-stabilized (PS) design to those of its recent evolution. Methods A consecutive group of 100 patients undergoing TKA using a classic cemented fixed-bearing PS TKA system was matched by age, gender, body max index to 100 patients having the newer cemented fixed-bearing PS design, both by the same manufacturer. Patients were assessed preoperatively, at 12 months and at 24 months minimum follow-up (range, 24-46) in a standard prospective fashion. The outcome assessments used were the Oxford Knee Score, the Knee Society Score, range of motion, and a satisfaction survey. A 2-sample t test comparing the 2 groups was performed. Results No patients were lost at follow-up. At 2-year follow-up, differences in clinical and radiological Knee Society Score (P = .09), Oxford Score (P = .08), and overall satisfaction rate did not reach statistical significance. Implant group 2 showed a statistically significant decrease in postoperative anterior knee pain (P = .006). At final follow-up, 16% of group 1 knees achieved > 130° flexion compared with 37% in group 2 (P = .0009). There were 2 revisions for any reason in group 1 and none in group 2. Conclusions Design modifications applied to the newer TKA system allowed greater flexion and lower patellofemoral complications but did not appear to achieve better overall clinical scores.

Shoulder joint loadings in post total hip replacement surgery patients during assisted walking: The influence of the crutch setup

A crutch is prescribed to permit the patient to walk safely and independently immediately after total hip replacement (THR) surgery. Purpose of this study is to evaluate the influence of the crutch setup on upper limbs biomechanics, including shoulder joint kinematics and kinetics parameters that will be evaluated to detect possible differences related to the crutch length. Thirty patients were randomly assigned to elbow flexed (EF) or elbow extended (EE) forearm crutch setup. Subjects were asked to walk on the laboratory path, instrumented with motion tracking system and force platforms. Spatiotemporal gait parameters, crutch ground reaction force (GRF) and crutch displacement (measured as the relative distance between the crutch position on the floor and the shoulder joint center), were evaluated. A three-dimensional (3D) biomechanical model was implemented to determine shoulder joint kinematics and kinetics during crutch walking. Results showed that the stride length significantly decreased, and base of support width increased for the EF group when compared to the EE group. Crutch forces and distance to the body significantly decreased in the EE group. Furthermore, shoulder joint moments in all planes of motion, vertical and lateral forces were significantly reduced in the EE group. The present study showed that crutch setup influenced performance and upper limb loading during walking, with EE setup allowing a more stable walking and reducing stress on the shoulder joint when compared to the EF setup. Results may help therapists in rationalizing crutch length adjustments for patients after THR surgery.

Controversy: Should All Patients Undergoing TJA Receive Pre- and Postoperative Ultrasound Screening for Detection of DVT?

Venous thromboembolism represents a frequent complication following total joint arthroplasty (TJA). Many international guidelines for deep venous thrombosis (DVT) prophylaxis do not recommend a preoperative lower limb duplex ultrasound before total hip and knee arthroplasty. This study is aimed at determining whether a preoperative Doppler ultrasonographic screening is cost-effective as a DVT and pulmonary embolism prevention device. A series of 2,678 consecutive patients undergoing TJA received preoperative assessment for DVT by bilateral lower limbs color Doppler ultrasonography. The study group included 1,697 females (63.3 %) and 981 males (36.7 %): all patients were included regardless of absence of previous vascular symptoms. Assessment included examination of bilateral common femoral, superficial femoral, popliteal, anterior tibial and posterior tibial veins. Preoperative ultrasound screening highlighted the presence of DVTs in 120 patients (4.5 %). Those patients were withdrawn from the operative schedule and began DVT treatment with personalized doses of LMWH (low molecular weight heparin). Patients underwent TJA procedure once the preoperative Doppler ultrasonography revealed absence of DVT (minimum 3 months; maximum 6 months). This study discovered a preoperative asymptomatic DVT in a consistent number of patients just before undergoing TJA: without screening they were at risk of developing possible life-threatening perioperative pathologies. Therefore we consider it prudent to perform a preoperative Doppler ultrasonography to detect any pre-existing DVT, especially in patients who are considered to be at high risk.

Unassisted quiet standing and walking after crutch usage in patients with total hip replacements: Does crutch length matter?

BACKGROUND Crutch use is prescribed early in the rehabilitation process following total hip replacement (THR) surgery to improve safety and promote return to active living. RESEARCH QUESTION Purpose of this study was to understand mid-term effects of crutch length setup on quiet standing and walking two months post-op when crutch use was no longer required. METHODS Thirty patients were evaluated 2 months post-surgery when they had been walking without crutch for a month. The patients had previously been assigned randomly to elbow flexed (EF) or elbow extended (EE) crutch set-ups and evaluated 3 days post-surgery. Quiet standing stability was assessed with participants standing in a comfortable position with each foot on separated force platforms, facing forward for 10 s. In addition, participants walked on the laboratory path, instrumented with motion tracking system and force platforms. For the quiet standing trial, centre of pressure measure, acromial height and lower limbs load bearing symmetry were evaluated. For the walking trial, spatiotemporal and ground reaction force (GRF) parameters were evaluated together with side symmetry indices. RESULTS Results showed no significant differences in any standing trial variables between groups. For walking, GRF parameters and symmetry indices were similar for both groups. However, increased base of support width, reduced self-selected walking speed and stride length were found for the EF group. SIGNIFICANCE This study showed that crutch set-up influenced gait after patients started to walk unassisted. Patients that previously used crutch adjusted according to the EE setup, demonstrated a more efficient gait with higher self-selected speed and longer and narrower stride. Clinicians may use these results for a proper crutch height adjustment, which improves walking and, in turn, functional recovery in post THR patients.

Correcting varus and valgus knee in total knee arthroplasty (TKA)

Abstract Correction of severe varus and valgus deformity in TKA requires a clear understanding of the location, orientation and biomechanical functions of the soft-tissue structures that provide stability to the knee. Correct ligament balancing in TKA allows for satisfactory knee proprioception, restores proper load transfer and theoretically improves implant survivorship. This chapter describes a stepwise approach to correcting varus and valgus deformity in TKA. When the deformity is fixed and not reducible, correction is more difficult to achieve. Significant varus or valgus malalignment on the coronal plane is very often associated with sagittal plane and torsional deformities: these deformities should be globally addressed in order to avoid a residual degree of deformity.