Comparing Outcomes of Tumor Prosthesis Revision and Locking Plate Fixation in Supracondylar Femoral Periprosthetic Fractures.

BACKGROUND: Periprosthetic fractures around a total knee replacement (TKR) can be complex and difficult to manage, requiring the surgical expertise of the trauma and arthroplasty surgeon. There are a number of treatment modalities available, each with their own merits and limitations. As data on tumor prosthesis revision in periprosthetic fractures is sparse, this study aims to evaluate the results of revision using a tumor prosthesis and compare them with those of fixation using a locking plate in periprosthetic fractures after TKR. METHODS: This is a retrospective study of 15 patients who underwent either tumor prosthesis revision (n = 7) or locking plate fixation (n = 8) for supracondylar femoral periprosthetic fractures in our hospital from 2009 and 2014. The mean follow-up time for these patients was 44 months. This study's main outcome measures were pain relief, return to premorbid ambulatory function, and complications. RESULTS: The revision and fixation groups saw five versus three patients achieve pain relief (71.4% vs. 37.5%, p = 0.315), and two versus four patients return to their premorbid ambulatory function (28.6% vs. 50%, p = 0.608) at the follow-up, respectively. The mean time to weight-bearing in the revision group and fixation group was 2.9 days and 18.9 weeks, respectively (p = 0.001). There were eight complications seen in the revision group with none requiring reoperation; there were five complications seen in the fixation group, and two required reoperation. CONCLUSIONS: The results of revision TKR using a tumor prosthesis were comparable to those of fixation using a locking plate in periprosthetic fractures after TKR. Tumor prosthesis revision may be considered as a viable alternative to locking plate fixation when indicated.

Alignment Analyses in the Varus Osteoarthritic Knee Using Computer Navigation.

Osteoarthritic (OA) knees with severe extension varus deformity seem to have correspondingly more severe flexion varus, especially beyond a certain tibiofemoral angle. Clinical measurement of flexion varus and fixed flexion deformity (FFD), which had been difficult to perform because of the spatial alignment of the knee in flexion, was recently made possible with computer navigation. We conducted a study to evaluate the relationship of extension and flexion varus in OA knees and to determine whether severity of FFD in the sagittal plane correlates with severity of coronal plane varus deformity. The study included 317 consecutive cases of computer-navigated total knee arthroplasty performed on OA knees with varus deformities. Three sets of values were extracted from the navigation data: varus angle at maximal knee extension, 90° knee flexion, and maximal knee extension. Correlation analyses were performed for extension and flexion varus, FFD, and coronal plane deformity. OA knees with extension varus of more than 10° had an incremental likelihood of more severe flexion varus. When the extension varus angle exceeded 20°, probability became almost certainty. There was no correlation between FFD and coronal plane varus deformity.

Functional discharge readiness and mobility following total knee arthroplasty for osteoarthritis: a comparison of analgesic techniques.

OBJECTIVE: To determine if functional discharge readiness and mobility following total knee arthroplasty (TKA) for osteoarthritis is delayed after femoral nerve block (FNB) with or without patient-controlled analgesia (PCA) opioid compared with PCA opioid alone. METHODS: We analyzed secondary outcomes from a randomized controlled trial with 200 patients undergoing unilateral TKA. Experimental group 1 received single-injection FNB with intravenous PCA opioid, experimental group 2 received continuous FNB, and the control group received PCA opioid alone. FNB was administered using bupivacaine. Patients followed a structured TKA pathway. Discharge readiness outcomes included achievement of 90° knee flexion, independent walking, and stair climbing, and were assessed daily before discharge or day 6, whichever came first. Mobility outcomes included the Timed Up and Go (TUG) test, the 6-Minute Walk Distance (6MWD), and self-reported physical function, and were assessed at weeks 2 and 12. TUG was also assessed on days 3 to 6, postoperation. RESULTS: Both FNB groups (77%) were more likely to achieve 90° knee flexion compared with the control group (59%); odds ratio (OR) 2.3, 95% confidence interval (95% CI) 1.1, 4.8 for single-injection FNB, and OR 2.3, 95% CI 1.1, 4.9 for continuous FNB. There were no significant differences in independent walking and stair-climbing ability before discharge, TUG, 6MWD, or self-reported physical function, between the FNB groups compared with the control group. CONCLUSION: After TKA, FNB (single-injection with PCA opioid or continuous) does not delay achievement of 90° knee flexion or other measures of functional discharge readiness and mobility compared with PCA opioid alone.

Patients with knee osteoarthritis demonstrate improved gait pattern and reduced pain following a non-invasive biomechanical therapy: a prospective multi-centre study on Singaporean population.

BACKGROUND: Previous studies have shown the effect of a unique therapy with a non-invasive biomechanical foot-worn device (AposTherapy) on Caucasian western population suffering from knee osteoarthritis. The purpose of the current study was to evaluate the effect of this therapy on the level of symptoms and gait patterns in a multi-ethnic Singaporean population suffering from knee osteoarthritis. METHODS: Fifty-eight patients with bilateral medial compartment knee osteoarthritis participated in the study. All patients underwent a computerized gait test and completed two self-assessment questionnaires (WOMAC and SF-36). The biomechanical device was calibrated to each patient, and therapy commenced. Changes in gait patterns and self-assessment questionnaires were reassessed after 3 and 6 months of therapy. RESULTS: A significant improvement was seen in all of the gait parameters following 6 months of therapy. Specifically, gait velocity increased by 15.9%, step length increased by 10.3%, stance phase decreased by 5.9% and single limb support phase increased by 2.7%. In addition, pain, stiffness and functional limitation significantly decreased by 68.3%, 66.7% and 75.6%, respectively. SF-36 physical score and mental score also increased significantly following 6 months of therapy (46.1% and 22.4%, respectively) (P < 0.05 for all parameters). CONCLUSIONS: Singaporean population with medial compartment knee osteoarthritis demonstrated improved gait patterns, reported alleviation in symptoms and improved function and quality of life following 6 months of therapy with a unique biomechanical device. TRIAL REGISTRATION: Registration number NCT01562652.

Patient-specific instrumentation for total knee replacement verified by computer navigation: a case report.

Patient-specific instrumentation (PSI) enables better restoration of the mechanical axis in total knee replacement (TKR) than conventional instrumentation (alignment guides) does. We verified the accuracy of the PSI by computer navigation. The PSI jigs were accurate only if they were pinned accurately onto the distal femur and proximal tibia. Any slight malposition of the jigs leads to malalignment of the bone cuts. In the absence of computer navigation, the accuracy of the jig alignments cannot be checked and may result in malalignment.

11th Yahya Cohen Memorial Lecture: An in vivo comparative study of the ability of derived mesenchymal stem cells in the treatment of partial growth arrest.

Few in vivo studies had previously been attempted in reaffirming the in vitro data in current literature. This study evaluated the ability of mesenchymal stem cells (MSCs) isolated from bone marrow, periosteum and fat to treat partial growth arrest in immature New Zealand white (NZW) rabbits. A physeal arrest model in an immature rabbit was created. The bony bridge was excised 3 weeks later, and MSCs from various sources were transferred into the physeal defect of different rabbits. Group I consisted of bone marrow-derived MSCs, Group II: periosteumderived MSCs, Group III: fat-derived MSCs. Contra-lateral tibiae, without undergoing operation, served as self-control. The animals were subsequently sacrificed, with radiological and histological analyses performed. All MSCs demonstrated chondrogenic and osteogenic differentiation potentials in vitro. In correction of varus angulation groups I and II exhibited superior results when compared to group III (P <0.05). The length discrepancies between operated and normal tibiae in groups I, II and III were significantly corrected when compared to the control group (P <0.01). In conclusion, bone marrow and periosteum derived stem cells provided better correction of physeal arrest in rabbits. The source of MSCs itself could influence the success in the treatment of growth arrest.

Comparative study of the ability of mesenchymal stem cells derived from bone marrow, periosteum, and adipose tissue in treatment of partial growth arrest in rabbit.

This study evaluates the ability of MSCs isolated from different origins--bone marrow, periosteum, or fat--to treat partial growth arrest in immature (6-week-old) New Zealand White rabbits. Up to 50% of the medial half of the proximal physis of the tibia was excised in these New Zealand White rabbits. Three weeks later, the bony bridge was excised, and fibrin glue with and without MSCs were transferred into the physeal defect of different rabbits. Contralateral tibias, without undergoing operation, served as self-control. Four groups of rabbits were involved in the study. Each group was injected separately with bone marrow-derived MSCs (group I), periosteum-derived MSCs (group II), fat-derived MSCs (group III), and fibrin glue alone (control, group IV). The rabbits were killed 8 and 16 weeks postoperatively. Clinical, radiological, and histological analyses were subsequently performed. Similar proliferative rates for three MSCs were demonstrated on days 4, 7, and 11 of primary culture. However, MSCs derived from bone-marrow and periosteum appeared to be more homogeneous than that from fat. All MSCs demonstrated chondrogenic and osteogenic differentiation potentials in vitro. The tibias in groups I and II showed significant correction of varus angulation at 16 weeks. However, the varus angulation in group III remained significantly obvious when compared with group I (p < 0.05). The length discrepancies between operated and normal tibiae in groups I, II, and III were significantly corrected compared with control (p < 0.01). In conclusion, bone-marrow and periosteum yielded more homogenous MSCs than fat, providing better correction of physeal arrest in rabbits. The source of MSCs itself could influence the success in the treatment of growth arrest.