High tibial osteotomy versus unicompartmental knee arthroplasty for Kellgren-Lawrence grade 3-4 knee osteoarthritis in younger patients: comparable improvements in patient-reported outcomes, adjusted for osteoarthritis grade and sex.

PURPOSE: Previous studies comparing high tibial osteotomy (HTO) with unicompartmental knee arthroplasty (UKA) have seldom accounted for differing patient characteristics between both groups. This study compared patient-reported outcomes (PROs) of HTO and UKA patients, adjusted for preoperative PROs, osteoarthritis grade and sex. METHODS: A retrospective study was performed analysing prospectively collected PROs, namely the Oxford Knee Score (OKS) and pain/satisfaction scores, collected preoperatively and at 6 months, 12 months and 24 months postoperatively. Consecutive medial opening-wedge HTOs and medial UKAs from 2016-2019, with a preoperative Kellgren-Lawrence grade ≥ 3, aged 50-60 years, were included. Linear mixed model analyses, with the OKS over time as the primary outcome, were used. RESULTS: We included 84 HTO patients (mean age 55.0 ± 3.0, 79% male, mean BMI 27.8 ± 3.4, 75% Kellgren-Lawrence grade 3) and 130 UKA patients (mean age 55.7 ± 2.8, 47% male, mean BMI 28.7 ± 4.0, 36% Kellgren-Lawrence grade 3). Response rates were ≥ 87% at all time points. Corrected for preoperative PROs, Kellgren-Lawrence grade and sex, the HTO group had a 2.5 (95% CI 1.0-4.0) points lower OKS over time than the UKA group (p = 0.001). The Numeric Rating Scale scores (NRS; 0-10) for pain at rest and during activity were higher (p < 0.01) in the HTO group. The EQ-5D-descriptive system (p < 0.01), NRS satisfaction (p < 0.01), anchor function and pain scores (p < 0.01) were lower over time in the HTO group. CONCLUSION: UKA patients had better OKS scores, pain and satisfaction scores over time than HTO patients. However, the observed differences were below their established minimal clinically important differences. Therefore, from the patients' perspective, HTO did not appear to be inferior to UKA under the indications outlined in this study. Level of evidence Level IV.

Opening- and closing-wedge high tibial osteotomy are comparable and early full weight bearing is safe with angular stable plate fixation: a meta-analysis.

PURPOSE: The purpose of this study was to establish the gold standard for surgical technique, fixation, and rehabilitation for HTO in patients with unicompartmental knee osteoarthritis. METHODS: Medline, Embase, and SPORTDiscus databases were searched up to April 2022. Included were (1) randomized controlled trials (RCTs) comparing opening-wedge HTO (owHTO) and closing-wedge HTO (cwHTO), (2) biomechanical studies and prospective patient studies comparing biomechanical and clinical results for plate fixators, and (3) RCTs comparing an early versus delayed full-weight-bearing (FWB) protocol. RESULTS: The pooled results for the surgical technique showed no significant differences between owHTO and cwHTO for most PROMs on pain, activity, and risk for conversion to TKA. The cwHTO group showed a slightly better improvement in KOOS/WOMAC pain scores (4.51; 95% CI 1.18-7.85), and a significantly lower change in posterior tibial slope (p = 0.03). The pooled results for the fixation method showed the highest force at maximum failure for the Activmotion (Newclip Technics, France), Aescula (B. Braun Korea, Korea), 2nd generation Puddu (Arthrex Inc., USA), and TomoFix plate (Depuy Synthes, Switzerland). The pooled results for the rehabilitation protocol showed no significant differences between the early full-weight-bearing (FWB) group and the delayed FWB group for functional scores, complication rates, and delayed unions. CONCLUSION: Both owHTO and cwHTO reduced pain and improved knee function. Locking plate fixation should be used for owHTO. An early FWB protocol has proven to be safe in patients with small corrections, no hinge fractures, and non-smokers. LEVEL OF EVIDENCE: Level II.

Subchondral bone changes after joint distraction treatment for end stage knee osteoarthritis.

OBJECTIVE: Increased subchondral cortical bone plate thickness and trabecular bone density are characteristic of knee osteoarthritis (OA). Knee joint distraction (KJD) is a joint-preserving knee OA treatment where the joint is temporarily unloaded. It has previously shown clinical improvement and cartilage regeneration, indicating reversal of OA-related changes. The purpose of this research was to explore 3D subchondral bone changes after KJD treatment using CT imaging. DESIGN: Twenty patients were treated with KJD and included to undergo knee CT imaging before, one, and two years after treatment. Tibia and femur segmentation and registration to canonical surfaces were performed semi-automatically. Cortical bone thickness and trabecular bone density were determined using an automated algorithm. Statistical parametric mapping (SPM) with two-tailed F-tests was used to analyze whole-joint changes. RESULTS: Data was available of 16 patients. Subchondral cortical bone plate thickness and trabecular bone density were higher in the weight-bearing region of the most affected compartment (MAC; mostly medial). Especially the MAC showed a decrease in thickness and density in the first year after treatment, which was sustained towards the second year. CONCLUSIONS: KJD treatment results in bone changes that include thinning of the subchondral cortical bone plate and decrease of subchondral trabecular bone density in the first two years after treatment, potentially indicating a partial normalization of subchondral bone.

Medial closing wedge high tibial osteotomy for valgus tibial deformities: good clinical results and survival with a mean 4.5 years of follow-up in 113 patients.

PURPOSE: A varus-producing medial closing wedge high tibial osteotomy (MCWHTO) is an uncommon procedure. The aim of this retrospective study was to assess the survivorship and prevalence of post-operative subjective knee laxity and satisfaction in a large cohort of patients with a MCWHTO performed without a MCL-reefing procedure. METHODS: All patients (n = 176) who underwent a MCWHTO in our clinic between 2008 and 2016 were approached to participate. After review of patient charts, questionnaires were sent to willingly patients. Primary outcome was the survivorship of the MCWHTO; secondary outcome was patient-reported instability and satisfaction. RESULTS: One-hundred and thirteen patients participated in the study. The 5-year survival rate of the MCWHTO was almost 80%. A total of 77% of the patients was satisfied with the treatment. With regard to post-operative subjective knee laxity, 26% of the patients experienced instability of the knee post-operation. Instability was significantly correlated with the KOOS domains, the Lysholm score, the IKDC knee function score and the Physical and Mental Health Domains of the SF-36. CONCLUSION: Medial closing wedge high tibial osteotomy provides good results regarding survivorship and patient satisfaction for patients with a valgus deformity which is located in the proximal tibia. Clinically relevant is that in the surgical technique without MCL-reefplasty instability is significantly correlated with worse patient-reported outcome measures. The addition of a MCL reefing procedure will improve outcome in selected patients. LEVEL OF EVIDENCE: III.

Medial collateral ligament laxity in valgus knee deformity before and after medial closing wedge high tibial osteotomy measured with instrumented laxity measurements and patient reported outcome.

INTRODUCTION: Medial closing wedge high tibial osteotomy (CWHTO) for valgus deformity correction was first described by Coventry whom performed an additional reefing of the medial collateral ligament (MCL) to prevent instability postoperative. In our clinic the additional reefing procedure has never been performed and instability has not been reported routinely by patients. Using instrumented laxity testing, pre- and postoperative valgus and varus knee laxity can be measured objectively. We hypothesize that absence of changes in laxity testing and subjective knee stability scores support that no additional reefing procedure is necessary. MATERIALS AND METHODS: In a prospective cohort study 11 consecutive patients indicated for medial CWHTO were subjected to pre- and postoperative stress X-rays in 30° and 70° of flexion and opening of the joint line was measured in degrees on the radiographs. Patient reported outcome scores were documented with the KOOS, Lysholm, SF36, Oxford Knee Score and a VAS instability scoring tool. RESULTS: All patients (7 females) completed the study, mean age was 46 years. Mean preoperative Hip Knee Ankle angle 6.4° valgus was corrected to mean postoperative alignment 0.1° valgus. A significant difference was measured between mean pre- and postoperative 30° valgus laxity (2.8° vs 5.3°, P = 0.005), 30° varus laxity (6.7° vs 3.2°, P = 0.005) and 70° valgus laxity (2.0° vs 4.8°, P = 0.008). Postoperative patient-reported knee instability as measured with the Lysholm questionnaire was significantly improved compared to preoperative instability (P = 0.006). VAS instability improved, but didn't reach significance (8.0 preoperative and 5.5 postoperative (P = 0.127). Other outcome measures showed improvement as well. No correlations between radiological findings and outcome scores were found. CONCLUSION: A significant increase in postoperative valgus laxity in 30° and 70° of flexion deems reconsidering addition of MCL reefingplasty to the medial CWHTO although patient reported outcome on subjective stability scores fails to report increase of instability in this study population. Instrumented laxity measurements of medial CWHTO patients treated with additional medial reefingplasty should be performed to prove the value of this procedure.

Knee joint distraction compared with total knee arthroplasty: a randomised controlled trial.

AIMS: Knee joint distraction (KJD) is a relatively new, knee-joint preserving procedure with the goal of delaying total knee arthroplasty (TKA) in young and middle-aged patients. We present a randomised controlled trial comparing the two. PATIENTS AND METHODS: The 60 patients ≤ 65 years with end-stage knee osteoarthritis were randomised to either KJD (n = 20) or TKA (n = 40). Outcomes were assessed at baseline, three, six, nine, and 12 months. In the KJD group, the joint space width (JSW) was radiologically assessed, representing a surrogate marker of cartilage thickness. RESULTS: In total 56 patients completed their allocated treatment (TKA = 36, KJD = 20). All patient reported outcome measures improved significantly over one year (p < 0.02) in both groups. At one year, the TKA group showed a greater improvement in only one of the 16 patient-related outcome measures assessed (p = 0.034). Outcome Measures in Rheumatology-Osteoarthritis Research Society International clinical response was 83% after TKA and 80% after KJD. A total of 12 patients (60%) in the KJD group sustained pin track infections. In the KJD group both mean minimum (0.9 mm, standard deviation (sd) 1.1) and mean JSW (1.2 mm, sd 1.1) increased significantly (p = 0.004 and p = 0.0003). CONCLUSION: In relatively young patients with end-stage knee osteoarthritis, KJD did not demonstrate inferiority of outcomes at one year when compared with TKA. However, there is a high incidence of pin track infection associated with KJD. Cite this article: Bone Joint J 2017;99-B:51-8.

Knee joint distraction compared with high tibial osteotomy: a randomized controlled trial.

PURPOSE: Both, knee joint distraction as a relatively new approach and valgus-producing opening-wedge high tibial osteotomy (HTO), are knee-preserving treatments for knee osteoarthritis (OA). The efficacy of knee joint distraction compared to HTO has not been reported. METHODS: Sixty-nine patients with medial knee joint OA with a varus axis deviation of <10° were randomized to either knee joint distraction (n = 23) or HTO (n = 46). Questionnaires were assessed at baseline and 3, 6, and 12 months. Joint space width (JSW) as a surrogate measure for cartilage thickness was determined on standardized semi-flexed radiographs at baseline and 1-year follow-up. RESULTS: All patient-reported outcome measures (PROMS) improved significantly over 1 year (at 1 year p < 0.02) in both groups. At 1 year, the HTO group showed slightly greater improvement in 4 of the 16 PROMS (p < 0.05). The minimum medial compartment JSW increased 0.8 ± 1.0 mm in the knee joint distraction group (p = 0.001) and 0.4 ± 0.5 mm in the HTO group (p < 0.001), with minimum JSW improvement in favour of knee joint distraction (p = 0.05). The lateral compartment showed a small increase in the knee joint distraction group and a small decrease in the HTO group, leading to a significant increase in mean JSW for knee joint distraction only (p < 0.02). CONCLUSION: Cartilaginous repair activity, as indicated by JSW, and clinical outcome improvement occurred with both, knee joint distraction and HTO. These findings suggest that knee joint distraction may be an alternative therapy for medial compartmental OA with a limited mechanical leg malalignment. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.

Distal femoral valgus osteotomy: bone healing time in single plane and biplanar technique.

Varus deformity can be localized in the tibia, in the femur or in both. If varus deformity is localized within the femur, it is mandatory to correct it in the femur. This report presents the technique and results of a consecutive case series of lateral uniplanar and biplanar closed-wedge valgus osteotomy of the distal femur for the treatment of varus deformity of the knee. Retrospectively, fifteen patients (sixteen knees) were identified. Indications for surgery varied from unloading an osteoarthritic medial compartment to reduction to symmetrical varus leg alignment. Pre- and post-operative X-rays, including a full leg radiograph, were assessed as well as bone healing time at follow-up intervals. Clinical outcome was assessed using different questionnaires. There were nine male and six female patients with a median age at surgery of 45 (±14) years. The mLDFA changed from 95.9° (±2.7°) preoperatively to 89.3° (±2.9°) post-operatively. Preoperative planning and the use of angle stable implants resulted in accurate corrections according to preoperative aims in all but one patient. At follow-up (mean, 40 months), the mean VAS score was 2.5 (±2.4) and the WOMAC score averaged 80 (±20). The mean bone healing time of biplanar osteotomies (4 ± 3 months) was shorter than in the uniplanar osteotomies (6 ± 3 months). Distal lateral closed-wedge valgus osteotomy of the femur for the treatment of femoral varus deformities resulted in clinical improvement and accurate corrections in patients with different aims for correction. A biplanar osteotomy technique shortens bone healing time.

Six weeks of continuous joint distraction appears sufficient for clinical benefit and cartilaginous tissue repair in the treatment of knee osteoarthritis.

BACKGROUND: Knee joint distraction (KJD) is a surgical joint-preserving treatment in which the knee joint is temporarily distracted by an external frame. It is associated with joint tissue repair and clinical improvement. Initially, patients were submitted to an eight-week distraction period, and currently patients are submitted to a six-week distraction period. This study evaluates whether a shorter distraction period influences the outcome. METHODS: Both groups consisted of 20 patients. Clinical outcome was assessed by WOMAC questionnaires and VAS-pain. Cartilaginous tissue repair was assessed by radiographic joint space width (JSW) and MRI-observed cartilage thickness. RESULTS: Baseline data between both groups were comparable. Both groups showed an increase in total WOMAC score; 24±4 in the six-week group and 32±5 in the eight-week group (both p<0.001). Mean JSW increased 0.9±0.3mm in the six-week group and 1.1±0.3mm in the eight-week group (p=0.729 between groups). The increase in mean cartilage thickness on MRI was 0.6±0.2mm in the eight-week group and 0.4±0.1mm in the six-week group (p=0.277). CONCLUSIONS: A shorter distraction period does not influence short-term clinical and structural outcomes statistically significantly, although effect sizes tend to be smaller in six week KJD as compared to eight week KJD.

Periosteal vascularization of the distal femur in relation to distal femoral osteotomies: a cadaveric study.

BACKGROUND: The purpose of this study was to investigate periosteal vessels location as intra-operative landmarks in distal femoral osteotomies and focused on the branching pattern of the vascular supply of the medial and lateral femoral condyle, its constancy, and the relationship to the height of distal femoral osteotomies. Anastomoses of relevant vessels were studied to analyze the risk of vascular insufficiency after transection of landmark vessels. METHODS: A human cadaver dissection study on the vascular supply of the medial and lateral side of the distal femur was conducted. Surgical dissection was performed in eight knees in total. Distances between the vascular supply and bony landmarks were calculated. Relation of the vascular structures to the transverse bone cuts of distal femoral osteotomies was described, as well as anastomoses of relevant vessels. RESULTS: On the medial side of the distal femur the periosteum was primarily supplied by the descending genicular artery (DGA) in 87.5 % of the specimens. In the absence of the DGA, the superior medial genicular artery was the supplier. Vascularization took place through two constant branches, the upper transverse artery (UTA) and the central longitudinal artery. The UTA originated at a mean distance of 6.9 cm (range 5.9-7.9 cm) above the knee joint line. On the lateral side of the distal femur the superior lateral genicular artery was the main vessel. In all dissected knees it gave off the lateral transverse artery (LTA). The LTA originated at a mean distance of 6.9 cm (range 5.8-7.6 cm) above the knee joint line. Anastomoses between the UTA, LTA and the longitudinal arch of the femoral shaft were found that could prevent vascular insufficiencies after transection of the UTA and LTA. CONCLUSIONS: The vascular supply of the medial and lateral aspects of the femoral condyle is highly constant. Both the UTA, on the medial side, and the LTA, on the lateral side, can serve as a landmark for orthopedic surgeons in determining the height of the osteotomy cuts in distal femoral osteotomies. Transection of these landmark vessels during the osteotomy will not result in vascular insufficiency because of a collateral supply.

Supracondylar femur osteotomies around the knee: patient selection, planning, operative techniques, stability of fixation, and bone healing.

BACKGROUND: Similar to the re-appreciation of high tibial osteotomy (HTO), supracondylar distal femur varus osteotomy (SCO) for lateral compartment osteoarthritis (OA) of the knee has gained renewed interest as new knowledge has become available on the influence of malalignment on the development, progression and symptoms of OA. Furthermore, the less than optimal results of knee replacements (TKR) in younger patients have also led to renewed interest in joint-preserving treatment options. PURPOSE: Varus SCO has not had the same success or widespread use as valgus HTO. The goal in SCO is similar to HTO, to shift the load from the diseased to the healthy compartment, in order to reduce pain, improve function and delay placement of a TKR. Valgus OA however occurs much less frequently than varus OA and varus SCO is considered a technically more demanding procedure. In the past the surgical techniques for SCO were mainly dependent on difficult-to-use implants making the procedure more complex. Complication rates related to the failure of fixation up to 16% have been reported. DISUSSION: The new biplane osteotomy technique fixated with a locking compression plate is very stable; bone healing potential is optimal using this technique and takes 6-8 weeks. Full weight bearing before full bone healing is possible without loss of correction. CONCLUSION: In this article, patient selection, planning, surgical techniques, stability of fixation, and bone healing are discussed. Varus supracondylar osteotomy is a viable treatment option for a well-defined patient group suffering from valgus malalignment and lateral compartment osteoarthritis, and in addition may be considered in ligamentous imbalance and lateral patellofemoral maltracking.

[Supracondylar femur osteotomies around the knee. Patient selection, planning, operative techniques, stability of fixation, and bone healing]. / Suprakondyläre Femurosteotomien in Kniegelenknähe. Patientenauswahl, Planung, Operationstechniken, Fixationsstabilität und Knochenheilung.

BACKGROUND: Similar to the reappreciation of high tibial osteotomy (HTO), supracondylar distal femur varus osteotomy (SCO) for lateral compartment osteoarthritis (OA) of the knee has gained renewed interest as new knowledge has become available on the influence of malalignment on the development, progression and symptoms of OA. Furthermore, the less than optimal results of total knee replacement (TKR) in younger patients have also led to renewed interest in joint-preserving treatment options. PURPOSE: Varus SCO has not had the same success or widespread use as valgus HTO. The goal in SCO is similar to HTO, to shift the load from the diseased to the healthy ompartment, in order to reduce pain, improve function and delay placement of a TKR. Valgus OA however occurs much less frequently than varus OA and varus SCO is considered a technically more demanding procedure. In the past the surgical techniques for SCO were mainly dependent on difficult-to-use implants making the procedure more complex. Complication rates related to the failure of fixation up to 16 % have been reported. DISUSSION: The new biplane osteotomy technique fixated with a locking compression plate is very stable; bone healing potential is optimal using this technique and takes 6-8 weeks. Full weight bearing before full bone healing is possible without loss of correction. CONCLUSION: In this article patient selection, planning, surgical techniques, stability of fixation and bone healing for SCO are discussed. In the past the surgical techniques for SCO were mainly dependent on difficult to use implants making the procedure more complex. Complication rates related to the failure of fixation of up to 16 % have been reported.

The safety and feasibility of a less invasive distal femur closing wedge osteotomy technique: a cadaveric dissection study of the medial aspect of the distal femur.

PURPOSE: To investigate the feasibility and safety of a less invasive surgical approach to the distal medial aspect of the femur in supracondylar medial closing wedge osteotomy for the treatment of lateral compartment osteoarthritis of the knee. The aim of a less invasive approach is to minimize soft tissue disruption, reduce damage to neurovascular structures and thereby prevent muscle atrophy and optimize bone healing potential. METHODS: A human cadaver dissection study on the vascular and neural structures of the medial side of the distal femur was conducted. Surgical dissection (n = 4), cryomicrotomy and subsequent 3D reconstruction of the anatomy (n = 1), and surgical dissection after performance of a supracondylar osteotomy through a less invasive approach (n = 1) were performed in 6 legs in total. RESULTS: The surgical dissection and 3D reconstruction showed that a branch of the femoral artery, the distal genicular artery, supplies the distal area of the vastus medialis (VM) muscle. This artery has several branching patterns; crucial in the presented less invasive approach is its musculo-articular branch, which has an oblique course through the VM to the superomedial pole of the patella. The femoral nerve and saphenous nerve innervate the VM. These structures are at risk in the traditional subvastus approach, whereas no major damage was observed in the leg in which a less invasive approach was performed. CONCLUSIONS: In this cadaveric dissection study, a less invasive approach to the medial side of the distal femur proved to be feasible and safe. Damage to the VM and its neurovascular structures is minimized as compared to the traditional subvastus approach.

dGEMRIC as a tool for measuring changes in cartilage quality following high tibial osteotomy: a feasibility study.

OBJECTIVE: The high tibial osteotomy (HTO) is an effective strategy for treatment of painful medial compartment knee osteoarthritis. Effects on cartilage quality are largely unknown. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) enables non-invasive assessment of cartilage glycosaminoglycan content. This study aimed to evaluate if dGEMRIC could detect relevant changes in cartilage glycosaminoglycan content following HTO. DESIGN: Ten patients with medial compartment osteoarthritis underwent a dGEMRIC scan prior to HTO, and after bone healing and subsequent hardware removal. A dGEMRIC index (T1Gd) was used for changes in cartilage glycosaminoglycan content, a high T1Gd indicating a high glycosaminoglycan content and vice versa. Radiographic analysis included mechanical axis and tibial slope measurement. clinical scores [knee osteoarthritis outcome scale (KOOS), visual analogue score (VAS) for pain, Knee Society clinical rating system (KSCRS)] before, 3 and 6 months after HTO and after hardware removal were correlated to T1Gd changes. RESULTS: Overall a trend towards a decreased T1Gd, despite HTO, was observed. Before and after HTO, lateral femoral condyle T1Gd was higher than medial femoral condyle (MFC) T1Gd and tibial cartilage T1Gd was higher than that of femoral cartilage (P < 0.001). The MFC had the lowest T1Gd before and after HTO. Clinical scores all improved significantly (P < 0.01), KOOS Symptoms and QOL were moderately related to changes in MFC T1Gd. CONCLUSIONS: dGEMRIC effectively detected differences in cartilage quality within knee compartments before and after HTO, but no changes due to HTO were detected. Hardware removal post-HTO seems essential for adequate T(1)Gd interpretation. T(1)Gd was correlated to improved clinical scores on a subscore level only. Longer follow-up after HTO may reveal lasting changes. ClinicalTrials.gov registration ID: NCT01269944.

Axial and torsional stability of supracondylar femur osteotomies: biomechanical comparison of the stability of five different plate and osteotomy configurations.

PURPOSE: Little is known regarding the biomechanical stability and stiffness of implants and techniques used in supracondylar femur osteotomies (SCO). Therefore, fixation stability and stiffness of implants to bone was investigated under simulated physiological loading conditions using a composite femur model and a 3D motion-analysis system. METHODS: Five osteotomy configurations were investigated: (1) oblique medial closing-wedge fixated with an angle-stable implant; (2) oblique and (3) perpendicular medial closing-wedge, both fixated with an angled blade plate; and lateral opening-wedge fixated with (4) a spacer plate and (5) an angle-stable lateral implant. The motion measured at the osteotomy was used to calculate the stiffness and stability of the constructs. RESULTS: The least amount of motion and highest stiffness was measured in the medial oblique closing-wedge osteotomy fixated with the angled blade plate. The lateral opening-wedge techniques were less stable and had a lower stiffness compared with the medial; the oblique saw cuts were more stable and had a higher stiffness than the perpendicular. CONCLUSION: This experimental study presents baseline data on the differences in the primary stability of bone-implant constructs used in SCO. The data in this study can be used as reference for future testing of SCO techniques. Furthermore, it is recommended that based on the differences found, the early postoperative rehabilitation protocol is tailored to the stability and stiffness of the fixation method used.

Axial and torsional stability of an improved single-plane and a new bi-plane osteotomy technique for supracondylar femur osteotomies.

PURPOSE: An important disadvantage of the standard medial closing-wedge distal femur osteotomy for lateral compartment osteoarthritis of the knee is the immediate effects on the extensor mechanism function. Therefore, a novel bi-plane osteotomy technique was developed. The stability and stiffness of this newly developed technique and a modification of the proximal screw configuration were tested in a composite femur model and compared to the standard single-plane technique. Research question was if the new bi-plane technique and/or modified screw configuration would improve the stability and stiffness of the construct. METHODS: In 12 femurs, motion at the osteotomy under axial and torsion loading was measured using a 3D motion analysis system. All were subsequently tested to failure. The data recorded were used to calculate stability and stiffness of the constructs. RESULTS: The stability and stiffness were highest in the bi-plane technique under axial loads, but were lower under torsional loading, compared to the single-plane technique. The screw configuration modification improved axial stability and stiffness, but had no influence on torsional stability. CONCLUSION: In replicate femurs, the new bi-plane technique improved axial stability, but in contrast to what was theorized, decreased torsional stability, compared to the single-plane technique. The addition of a bi-cortical screw proximally improved stability under axial loading, but not torsion. Further clinical testing will have to prove if early full weight bearing using the new bi-plane technique is possible.

Fixation stability of opening- versus closing-wedge high tibial osteotomy: a randomised clinical trial using radiostereometry.

Valgus high tibial osteotomy for osteoarthritis of the medial compartment of the knee can be performed using medial opening- and lateral closing-wedge techniques. The latter have been thought to offer greater initial stability. We measured and compared the stability of opening- and closing-wedge osteotomies fixed by TomoFix plates using radiostereometry in a series of 42 patients in a prospective, randomised clinical trial. There were no differences between the opening- and closing-wedge groups in the time to regain knee function and full weight-bearing. Pain and knee function were significantly improved in both groups without any differences between them. All the osteotomies united within one year. Radiostereometry showed no clinically relevant movement of bone or differences between either group. Medial opening-wedge high tibial osteotomy secured by a TomoFix plate offers equal stability to a lateral closing-wedge technique. Both give excellent initial stability and provide significantly improved knee function and reduction in pain, although the opening-wedge technique was more likely to produce the intended correction.

Osteotomies around the knee: patient selection, stability of fixation and bone healing in high tibial osteotomies.

New developments in osteotomy techniques and methods of fixation have caused a revival of interest of osteotomies around the knee. The current consensus on the indications, patient selection and the factors influencing the outcome after high tibial osteotomy is presented. This paper highlights recent research aimed at joint pressure redistribution, fixation stability and bone healing that has led to improved surgical techniques and a decrease of post-operative time to full weight-bearing.

Comparison of two arthroscopic pump systems based on image quality.

The effectiveness of arthroscopic pump systems has been investigated with either subjective measures or measures that were unrelated to the image quality. The goal of this study is to determine the performance of an automated pump in comparison to a gravity pump based on objective assessment of the quality of the arthroscopic view. Ten arthroscopic operations performed with a gravity pump and ten performed with an automated pump (FMS Duo system) were matched on duration of the surgery and shaver usage, type of operation, and surgical experience. Quality of the view was defined by means of the presence or absence of previously described definitions of disturbances (bleeding, turbidity, air bubbles, and loose fibrous tissue). The percentage of disturbances for all operations was assessed with a time-disturbance analysis of the recorded operations. The Mann-Whitney U test shows a significant difference in favor of the automated pump for the presence of turbidity only (Exact Sig. [2*(1-tailed Sig.)] = 0.015). Otherwise, no differences were determined (Exact Sig. [2*(1-tailed Sig.)] > 0.436). A new objective method is successfully applied to assess efficiency of pump systems based on the quality of the arthroscopic view. Important disturbances (bleeding, air bubbles, and loose fibrous tissue) are not reduced by an automated pump used in combination with a tourniquet. The most frequent disturbance turbidity is reduced by around 50%. It is questionable if this result justifies the use of an automated pump for straightforward arthroscopic knee surgeries using a tourniquet.