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Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_4 | Pages 72 - 72
1 Mar 2021
Kok A den Dunnen S Lamberts K Kerkhoffs G Tuijthof G
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Surgical microfracture is considered a first line treatment for talar osteochondral defects. Pain reduction, functional improvement and patient satisfaction are described to be 61–86% in both primary and secondary osteochondral defects. However, limited research is available whether improvement of the surgical technique is possible. We do know that the current rigid awls and drills limit the access to all locations in human joints and increase the risk of heat necrosis of bone. Application of a flexible water jet instrument to drill the microfracture holes can improve the reachability of the defect without inducing thermal damage. The aim of this study is to determine whether water jet drilling is a safe alternative compared to conventional microfracture awls by studying potential side effects and perioperative complications, as well as the quality of cartilage repair tissue in a caprine model. 6 mm diameter talar chondral defects were created bilaterally in 6 goats (12 samples). One defect in each goat was treated with microfracture holes created with conventional awls. The contralateral defect was treated with holes created with 5 second water jet bursts at a pressure of 50 MPa. The pressure was generated with a custom-made setup using an air compressor connected to a 300 litre accumulator that powered an air driven high-pressure pump (P160 Resato, Roden, The Netherlands, www.resato.com). Postoperative complications were recorded. After 24 weeks, analyses were performed using the ICRS macroscopic score and the modified O'Driscoll histological score. Wilcoxon ranked sum tests were used to assess significant differences between the two instrument groups using each goat as its own control (p ≤ 0.05). One postoperative complication was signs of a prolonged wound healing with swelling and reluctance to weight bearing starting two days after surgery on the water jet side. Antibiotics were administered which resolved the symptoms. The median total ICRS score for the tali treated with water jets was 9,5 (range: 6–12) and 9 (range 2–11) for Observer 1 and 2 respectively; and for the tali treated conventionally this was 9,5 (range 5–11) and 9 range (2–10). The median total Modified O'Driscoll score for the tali treated with water jets was 15 (range: 7–17) and 13 (range: 3–20) for Observer 1 and 2 respectively; and for the tali treated conventionally was 13 (range: 11–21) and 15 (range: 9–20). No differences were found in complication rate or repair tissue quality between the two techniques. The results suggest that water jet drilling can be a safe alternative for conventional microfracture treatment. Future research and development will include the design of an arthroscopic prototype of the water jet drill. The focus will be on stability in nozzle positioning and minimized sterile saline consumption to further the decrease the risk of soft tissue damage.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_9 | Pages 81 - 81
1 May 2017
Bonnin M de Kok A Verstraete M Van Hoof T Van der Straten C Victor J
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Background

The goal of this study was (1) to investigate the relationships between the bony contours of the knee and the popliteus tendon before and after TKA and (2) to analyse the influence of implant sizing. Our hypothesis was that an apparently well-sized prosthesis, will modify the position or the tracking of popliteus tendon.

Methods

4 fresh frozen cadavers were selected. The popliteus tendon was injected with contrast dye and a CT-scan was performed from full extension to full flexion with increments of 20°. Afterwards a total knee arthroplasty (TKA) was performed. Each cadaver received either a normal-sized, oversized, undersized or mobile bearing prosthesis. After TKA the limb was scanned again using the same protocol as before. 3D-reconstructions were created using Materialise Mimics software. These 3D-models were then imported into custom made Matlab software to measure and compare the deviation of the popliteus tendon before and after TKA.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_1 | Pages 98 - 98
1 Jan 2017
Bonnin M Saffarini M de KoK A Verstraete M Van Hoof T Van der Straten C Victor J
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To determine the mechanisms and extents of popliteus impingements before and after TKA and to investigate the influence of implant sizing. The hypotheses were that (i) popliteus impingements after TKA may occur at both the tibia and the femur and (ii) even with an apparently well-sized prosthesis, popliteal tracking during knee flexion is modified compared to the preoperative situation.

The location of the popliteus in three cadaver knees was measured using computed tomography (CT), before and after implantation of plastic TKA replicas, by injecting the tendon with radiopaque liquid. The pre- and post-operative positions of the popliteus were compared from full extension to deep flexion using normosized, oversized and undersized implants (one size increments).

At the tibia, TKA caused the popliteus to translate posteriorly, mostly in full extension: 4.1mm for normosized implants, and 15.8mm with oversized implants, but no translations were observed when using undersized implants. At the femur, TKA caused the popliteus to translate laterally at deeper flexion angles, peaking between 80º-120º: 2.0 mm for normosized implants and 2.6 mm with oversized implants. Three-dimensional analysis revealed prosthetic overhang at the postero-superior corner of normosized and oversized femoral components (respectively, up to 2.9 mm and 6.6 mm).

A well-sized tibial component modifies popliteal tracking, while an undersized tibial component maintains more physiologic patterns. Oversizing shifts the popliteus considerably throughout the full arc of motion. This study suggests that both femoro- and tibio-popliteus impingements could play a role in residual pain and stiffness after TKA.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 47 - 47
1 May 2016
Bonnin M De Kok A Verstraete M Van Hoof T Van Der Straeten C Victor J
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Goals of the study

(1) to investigate the relationships between the bony contours of the knee and the Popliteus Tendon (PT) in the healthy knee and after implantation of a TKA and (2) to analyze the influence of implant sizing.

Hypothesis

With an apparently well-sized TKA, the position of the PT during knee flexion is modified compared with the preoperative situation.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLI | Pages 105 - 105
1 Sep 2012
Pinczewski L Gordon D Sri-Ram K Kok A Linklater J Salmon L
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Bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been shown to be associated with femoral tunnel widening and cyst formation.

To compare a poly-L-lactide–hydroxyapatite screw (PLLA-HA) with a titanium screw with respect to clinical and radiological outcomes over a 5 year period.

40 patients were equally randomized into 2 groups (PLLA-HA vs titanium) and ACLR performed with a 4 strand hamstring graft with femoral tunnel drilling via the anteromedial portal. Evaluation at 2 and 5 years was performed using the International Knee Documentation Committee assessment (IKDC), Lysholm knee score, KT 1000 arthrometer, single-legged hop test. Magnetic resonance imaging was used to evaluate tunnel and screw volume, ossification around the screws, graft integration and cyst formation.

There was no difference in any clinical outcome measure at 2 or 5 years between the 2 groups. At 2 years, the PLLA-HA femoral tunnel was significantly smaller than the titanium screw tunnel (p=0.015) and at 5 years, there was no difference. At 2 years the femoral PLLA-HA screw was a mean 76% of its original volume and by 5 years, 36%. At 2 years the tibial PLLA-HA screw mean volume was 68% of its original volume and by 5 years, 46%. At 5 years, 88% of femoral tunnels and 56% of tibial tunnels demonstrated a significant ossification response. There was no increase in cyst formation in the PLLA-HA group and no screw breakages.

The PLLA-HA screw provides adequate aperture fixation in ACLR with excellent functional outcomes. It was not associated with femoral tunnel widening or increased cyst formation when compared with the titanium screw. The resorbtion characteristics appear favourable and the hydroxyapatite component of the screw may stimulate osteoconduction, contributing to these results. The PLLA-HA screw is a good alternative to a titanium screw in ACLR, which may aid revision procedures and allow for imaging without artifact.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLI | Pages 104 - 104
1 Sep 2012
Roe J Hui C Ferguson D Kok A Salmon L Pinczewski L
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Anterior cruciate ligament (ACL) injuries are being seen with increasing frequency in children. Treatment of the ACL deficient knee in skeletally immature patients is controversial.

To determine the outcome of anatomic transphyseal ACL reconstruction in tanner stage 1 and 2 patients with open growth plates at a minimum of 2 years after surgery.

Between 2007–2008, 16 prepubescent skeletally immature patients underwent anatomic transphyseal ACL reconstruction using soft tissue grafts. All patients were tanner stage 1 and 2 and all had open growth plates. Outcomes were assessed at a minimum of 2 years after surgery and included: limb alignment, limb length, instrumented testing with KT-1000 and International Knee Documentation Committee (IKDC) score.

Mean age at the time of surgery was 12 years (8–14). Graft choices included: living-related donor hamstring tendon allograft (n=14), hamstring tendon autograft (n=1) and fresh frozen allograft (n=1). Mean IKDC subjective score was 96 (84–100). Sixty-two percent of patients had <3mm side-to-side difference on instrumented KT-1000 testing and 88% had a negative pivot shift. At 2 years after surgery, all patients had returned to strenuous activities and normal or nearly normal overall IKDC score was documented in 94% of patients. There were no cases of limb malalignment or growth arrest.

We present a large series of anatomic transphyseal ACL reconstruction in tanner stage 1 and 2 patients with open growth plates at a minimum of 2 years following surgery. Excellent clinical outcomes were obtained with high levels of return to desired activities. Importantly, no growth disturbances were seen in this series of patients.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLI | Pages 126 - 126
1 Sep 2012
Pinczewski L Leys T Kok A Linklater J Salmon L
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This prospective longitudinal study compares the results of isolated endoscopic ACL reconstruction utilizing 4-strand hamstring tendon (HT) or patellar tendon (PT) autograft over a 15-year period with respect to re-injury, clinical outcomes and the development of osteoarthritis.

90 consecutive patients with isolated ACL rupture were reconstructed with a PT autograft and 90 patients received HT autograft, with an identical surgical technique. Patients were assessed at 2, 5, 7, 10 and 15 years. Assessment included the IKDC Knee Ligament Evaluation including radiographic evaluation, KT1000, Lysholm Knee Score, kneeling pain, and clinical outcomes.

Subjects who received the PT graft had significantly worse outcomes compared to those who received the HT graft at 15 years for the variables of radiologically detectable osteoarthritis (p=0.03), motion loss (p=0.01), single leg hop test (p=0.002), participation in strenuous activity (p=0.05), and kneeling pain (p=0.04). There was no significant difference between the HT and PT groups in overall IKDC grade (p=0.31). ACL graft rupture occurred in 16% of HT group and 8% of the PT group (p=0.07). ACL graft rupture was associated with non-ideal tunnel position (odds ratio 5.0) and males (odds ratio 3.2). Contralateral ACL rupture occurred in significantly more PT patients (24%) than HT patients (12%) (p=0.03), and was associated with age < 18 years (odds ratio 4.1) and the patellar tendon graft (odds ratio 2.6). Radiologically detectable osteoarthritis at 15 years was associated with the PT graft (odds ratio 2.3).

Significant differences have developed in the groups at 15 years after surgery which were not seen at earlier reviews. Compared to the HT Group, the PT group had significantly worse outcomes with respect to radiological osteoarthritis, extension loss and functional tests but no significant difference in laxity was identified. There was a high incidence of ACL injury after reconstruction, to both the reconstructed and the contralateral knee.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIX | Pages 52 - 52
1 Jul 2012
Chana R Salmon L Kok A Pinczewski L
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Aim

To evaluate safety and efficacy of performing a total knee arthroplasty (TKA) on patients receiving continuous Warfarin therapy

Methods

We identified 24 consecutive patients receiving long term warfarin therapy who underwent total knee arthroplasty between 2006 and 2008. As a control, we collected the same data from a group of age and sex matched patients not on warfarin. Primary observations were changes in haemoglobin, transfusion rates and complications. Secondary observations were fluctuations in the INR and post operative range of motion (ROM). All procedures were performed by the senior author in a single centre using the same TKA technique.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 580 - 580
1 Nov 2011
Hui C Salmon L Kok A Maeno S Pinczewski L
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Purpose: The management of degenerative arthritis of the knee in the younger, active patient often presents a challenge to the orthopaedic surgeon. Surgical treatment options include: high tibial osteotomy (HTO), uni-compartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The purpose of this study was to examine the long-term survival of closing wedge HTO in a large series of patients 8–19 years after surgery.

Method: The results of 458 consecutive patients undergoing lateral closing wedge HTO for medial compartment osteoarthritis (MCOA) between 1990 and 2001 were reviewed. Between 2008–2009, patients were contacted via telephone and assessment included: incidence of further surgery, Oxford Knee Score, and British Orthopaedic Association (BOA) Patient Satisfaction Scale. Failure was defined as the need for revision HTO or conversion to UKA or TKA. Survival analysis was completed using the Kaplan-Meier method.

Results: We were able to contact 400/458 (87%) patients for follow-up via telephone interview. Five patients (1%) who declined participation were excluded. Fifty-eight patients (13%) were lost to follow-up. Of the 395 patients, 12 (3%) had died of unrelated causes and 124 (31%) required further knee surgery. The remaining 259 (66%) completed the BOA patient satisfaction score and Oxford Knee Score. The probability of survival for HTO at 5, 10 and 15 years was 95%, 79% and 55% respectively. Multivariate regression analysis showed that only age < 50 years (p< 0.001) was associated with significantly longer survival. Mean Oxford Knee Score was 40/48 (range 17–60). Ninety-two percent (239/259 patients) were enthusiastic or satisfied and 90% (234/259 patients) would undergo HTO again at mean 11 years follow-up. Complications included: 5 pulmonary embolisms, 8 deep vein thromboses, 1 non-union, 1 post-operative subarachnoid hemorrhage and 1 transient peroneal nerve palsy.

Conclusion: To our knowledge, we have reported the long-term follow-up of lateral closing wedge HTO in the largest group of patients in the literature. We found that the results of HTO do deteriorate over time but that HTO can be effective for as long as 19 years. In appropriately selected patients and circumstances, HTO gives high patient satisfaction and affords patients unrestricted activity for many years.