Abstract

Conventional proximal tibial osteotomy is a widely successful joint-preserving treatment for osteoarthritis; however, conventional procedures do not adequately control the posterior tibial slope (PTS). Alterations to PTS can affect knee instability, ligament tensioning, knee kinematics, muscle and joint contact forces as well as range of motion.

This study primarily aimed to provide a comprehensive investigation of the variables influencing PTS during high tibial osteotomy using a 3D surgical simulation approach. Secondly, it aimed to provide a simple means of implementing the findings in future 3D pre-operative planning and /or clinically.

The influence of two key variables: the gap opening angle and the hinge axis orientation on PTS was investigated using three independent approaches: (1) 3D computational simulation using CAD software to perform virtual osteotomy surgery and simulate the post-operative outcome. (2) Derivation of a closed-form mathematical solution using a generalised vector rotation approach (3) Clinical assessment of synthetically generated x-rays of osteoarthritis patients (n=28; REC reference: 17/HRA/0033, RD&E NHS, UK) for comparison against the theoretical/computational approaches.

The results from the computational and analytical assessments agreed precisely. For three different opening angles (6°, 9° and 12°) and 7 different hinge axis orientations (from −30° to 30°), the results obtained were identical. A simple analytical solution for the change in PTS, ΔP_s, based on the hinge axis angle, α, and the osteotomy opening angle, θ, was derived:

ΔP_s=sin^-1(sin α sin θ)

The clinical assessment demonstrated that the absolute values of PTS, and changes resulting from various osteotomies, matched the results from the two relative prediction methods.

This study has demonstrated that PTS is impacted by the hinge axis angle and the extent of the osteotomy opening angle and provided computational evidence and analytical formula for general use.

High tibial osteotomy (HTO) is an effective surgical treatment for isolated medial compartment knee osteoarthritis; however, widespread adoption is limited due to difficulty in achieving the planned correction, and patient dissatisfaction due to soft tissue irritation. A new HTO system – Tailored Osteotomy Knee Alignment (TOKA®, 3D Metal Printing Ltd, Bath, UK) could potentially address these barriers having a custom titanium plate and titanium surgical guides featuring a unique mechanism for precise osteotomy opening as well as saw cutting and drilling guides. The aim of this study was to assess the accuracy of this novel HTO system using cadaveric specimens; a preclinical testing stage ahead of first-in-human surgery according to the ‘IDEAL-D’ framework for device innovation.

Local ethics committee approval was obtained. The novel opening wedge HTO procedure was performed on eight cadaver leg specimens. Whole lower limb CT scans pre- and post-operatively provided geometrical assessment quantifying the discrepancy between pre-planned and post-operative measurements for key variables: the gap opening angle and the patient specific surgical instrumentation positioning and rotation - assessed using the implanted plate.

The average discrepancy between the pre-operative plan and the post-operative osteotomy correction angle was: 0.0 ± 0.2°. The R2 value for the regression correlation was 0.95.

The average error in implant positioning was −0.4 ± 4.3 mm, −2.6 ± 3.4 mm and 3.1 ± 1.7° vertically, horizontally, and rotationally respectively.

This novel HTO surgery has greater accuracy and smaller variability in correction angle achieved compared to that reported for conventional or other patient specific methods with published data available. This system could potentially improve the accuracy and reliability of osteotomy correction angles achieved surgically.

Abstract

Abstract

The radiographic or bony landmark techniques are the two most common methods to determine Medial patellofemoral ligament (MPFL) femoral tunnel placement. Their intra/inter-observer reliability is widely debated. The palpation technique relies on identifying the medial epicondyle (ME) and adductor Tubercle (AT). The central longitudinal artery and associated vessels (CLV) are consistently seen in the surgical dissection during MPFL reconstruction. The aim of this study was to investigate the anatomic relationship of CLV to ME-AT and thereby use CLV as an important vascular landmark during MPFL reconstruction.

A retrospective review of MRI scans in skeletally mature patients presenting to a tertiary referral knee clinic was undertaken. Group-N consisted of any presentation without patellofemoral instability or malalignment (PFI). Group-P with PFI. MRI's were reviewed and measured by two Consultant Radiologists for the CLV-ME-AT anatomy and relationship.

Following exclusions 50 patients were identified in each group. The CLV passed anterior to the AT and ME in all patients. ME morphology did not differ greatly between the groups except in the tubercle height, where there was a statically but not clinically significant difference (larger in the non-PFI group, 2.95mm vs 2.52mm, p=0.002). The CLV to ME Tip distance was consistent between the groups (Group PFI group 3.8mm & ‘normal’ non-PFI Group 3.9mm).

The CLV-ME-AT relationship remained consistent despite patients presenting pathology. The CLV consistently courses anterior to ME and AT. The CLV could be used as a vascular landmark assisting femoral tunnel placement during MPFL reconstruction.

Abstract

Abstract

Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability.

Cite this article: Bone Jt Open 2022;3(3):268–274.

Abstract

Background

The meniscal deficient knee often exists in the setting of associated pathology including instability, malalignment and chondral injury. Meniscal allograft transplantation (MAT) is established to be a reliable option in restoring function and treating symptoms. The aim of this study was to establish the role of MAT as part of a staged approach to treatment of the previously menisectomised knee.

Aim

This study aims to elucidate the effects of radiofrequency chondroplasty (RFC), a surgical technique for the treatment of damaged articular cartilage, at a microscopic scale. Here we report about two aspects of the study – a morphological analysis of the treated surface using nonlinear microscopy and Raman spectroscopy, and an investigation into changes in permeability to large and small molecules. Cartilage samples were obtained from

Patients with recurrent patella instability, who have an abnormal patellofemoral alignment (patella height or tibial tubercle-trochlear groove (TTTG) distance), benefit from tibial tubercle transfer along with medial patellofemoral ligament (MPFL) reconstruction. Between July 2008 and April 2013, 18 patients (21 knees) with recurrent patellar instability underwent combined MPFL reconstruction and tibial tubercle transfer. All patients had abnormal patellofemoral alignment in addition to MPFL insufficiency. 15 patients (16 knees) with a mean age of 24 years (16–41) had a mean follow up of 26 months (6–55). We assessed the outcome using KOOS, KUJALA, activity level and patient satisfaction scores. All patients had a stable patella. There was a significant improvement in outcome scores in 12 out of 15 patients. At final follow up KOOS score had improved from 68.25(44 to 93.9) to 77.05(48.8 to 96.4) and KUJALA score had improved from 63.3(41–88) to 78.06 (45 to 99). 9 patients showed excellent results and achieved at least a pre-injury level of activity. 4 of these had activity level better then preoperative level. 6 patients had a lower activity level than pre-injury (1 – ongoing physiotherapy, 1 – because of lack of confidence, and 4 – Life style modification). 14 patients were satisfied and happy to recommend this procedure. There were 3 postop complications, with 2 cases of stiffness and 1 case of non-union of the tibial tuberosity. Our prospective study has shown that restoration of tibial tubercle-trochlear groove index, Patella height and Medial Patellofemoral Ligament reconstruction yields good results in carefully selected patients.

Introduction

Anatomical reconstruction of the Anterior Cruciate Ligament (ACL) reconstruction has been shown to improve patient outcome. The posterior border of the anterior horn of the lateral meniscus (AHLM) is an easily identifiable landmark on MRI and arthroscopy, which could help plan tibial tunnel position in the sagittal plane and provide anatomical graft position intra-operatively.

The resection of distal femur and proximal tibia during TKR is 90° to mechanical axis but in a normal knee, the joint line is 3°varus. We measured various angles on long-leg alignment radiographs. The mean age was 58.7 years. The mean HKA axis was 4.3°± 0.5°, mPTA was 3.8°±0.5°, mLDFA was 3.6±0.5° and aLDFA was 8.6°±0.5°. The mean HKA & MPTA were approximately 4°varus, mLDFA 4° valgus & aLDFA 8°valgus. The alignment of the knee to its mechanical axis during TKR is therefore not anatomic. This raises a question whether the knee should be aligned to its kinematic axis instead of mechanical axis.

Kinematic alignment has increased in popularity over the last few years in an attempt to improve clinical outcomes following total knee arthroplasty (TKA).

In our unit kinematic alignment has been used with patient-specific cutting guides as part of on-going clinical trials. We performed a retrospective analysis on all the TKA which had been planned to be implanted outside of the mechanical axis (0° ± 3°) based on pre-operative MRI scans and looked at their radiographic and clinical outcomes.

We identified 21 knees which had been implanted as ‘planned outliers’. All had clinical and radiographic follow up to a mean 11.6 months post op. All had a standard long leg alignment radiograph performed at 6 weeks post op to confirm alignment.

All patients had a good improvement in their Oxford Knee Scores with mean improvement from 23 pre-op to 42 at 1 year. Of our patients none had a poor clinical outcome due to the alignment of their TKA, 1 patient had a poor outcome because of a quadriceps rupture which occurred 4 months post-op. There were no post-operative radiographic abnormalities.

In our unit kinematic alignment outside of the mechanical axis is not associated with an increased rate of short term complications.

Chondral damage within the knee commonly occurs during sport following direct trauma or following degeneration through overuse. Radio frequency energy chondroplasty (RFC) can be used as an alternative to mechanical chondroplasty in the arthroscopic treatment of chondral lesions. Current literature supports the theoretical advantage of RFC and purports to in vitro improvements in cartilage structure and function following RFC. We conducted a retrospective study of patients undergoing RFC for isolated chondral lesions in the knee and assessed the short term clinical benefits.

Retrospective analysis was completed of operative notes and arthroscopic images of all patients who underwent arthroscopic chondroplasty at the royal Devon and Exeter Hospital between January 2009 and June 2012. Inclusion criteria included 1 to 2 defined chondral lesions, less than 2cm2, of Outerbridge grade II-IV, treated via arthroscopic RFC. Exclusion criteria included diffuse articular cartilage damage, additional pathologies affecting the knee or subsequent further injuries or invasive procedures to the knee. Data was collected via a subjective and objective questionnaire assessing patient outcome.

35 patients met the inclusion criteria, 32 were successfully followed up. Male: female ratio was 16:16, with a mean age of 39.5 (range 19–60).

84% (n=27) of patients experienced a significant reduction in pain (mean reduction of 51%, p < 0.001) lasting until the time of study (median of 21 months, range 9 to 31 months). There was no correlation between change in symptoms and site and grade of chondral lesion. Pre-operative instability symptoms did not significantly improve following RFC. Satisfaction with treatment was in direct correlation with pain relief achieved.

Our study appears to support current literature by suggesting short term improvements to pain following the use of RFC on chondral lesions. Greater population size and longer follow-up are required to provide more significant conclusions.

Introduction

Anatomical reconstruction of the Anterior Cruciate Ligament (ACL) reconstruction has been shown to be desirable and improve patient outcome. The posterior border of the anterior horn of the lateral meniscus (AHLM) is an easily identifiable arthroscopic landmark, which could guide anatomic tibial tunnel position in the sagital plane. The aim of the study was to establish the relationship between the posterior border of AHLM and the centre of the ACL foot print to facilitate anatomical tibial tunnel placement.

We sought to validate a method of measuring the range of motion of knees on radiographs as part of a new system of “Virtual Knee Clinics”.

The range of motion of 52 knees in 45 patients were first obtained clinically with goniometers and compared to radiographs of these patients' knees in full active flexion and extension. Four methods of plotting the range of motion on the radiographs were compared.

The intra-class correlation coefficient (ICC) for inter-rater reliability using the goniometer was very high; ICC=0.90 in extension and 0.85 in flexion. The best ICC for radiographic measurement in extension was 0.86 indicating substantial agreement and best ICC in flexion was 0.95 (method 4). ICC for intra-rater reliability was 0.98 for extension and 0.99 for flexion on radiographic measurements.

Measuring range of motion of the knee has never previously been validated in the literature. This study has allowed us to set up a “Virtual Knee Clinic,” combining postal questionnaires and radiographic measurements as a surrogate for knee function. We aim to maintain high quality patient surveillance following knee arthroplasty, reduce our new to follow-up ratios in line with Department of Health guidelines and improve patient satisfaction through reduced travel to hospital outpatients.

The aim of this prospective study was to determine the prevalence of bone marrow oedema (BME) in asymptomatic knees of athletes and to investigate the factors associated with appearance of BME in this group.

A total of 25 asymptomatic athletes who competed at an international, national or county level during their most recent sport season were recruited in this study and had MRI scan of both knees (n=50). MRI scans were reported independently by two experienced musculoskeletal radiologists. Statistical analysis included Cohen's kappa test to identify inter-observer agreement for MRI diagnosis of bone marrow oedema and multiple logistic regression model to identify the factors associated with BME on MRI scan.

There was very good agreement between radiologists for diagnosis of BME (Kappa = 0.896). Seven participants (28%) were found to have BME. Six of the participants had BME in unilateral knees and one participant had BME in bilateral knees. The commonest location of BME was medial femoral condyle (62.5%) The amount of time spent in preseason training (34-38 weeks) was significantly associated with appearance of BME (P=0.048)

BME seems to be common in asymptomatic athletes and one should realize that this finding might not be related to the clinical complaints of the patients. The results of the present study show that there is a training effect associated with BME. Knowing what is a ‘normal’ or ‘abnormal’ scan is important for a competitive athlete, as erroneously diagnosing BME as the underlying cause of athletes' symptoms could lead to decreased playing time or inappropriate therapy.

The Oxford mobile bearing unicompartmental knee replacement (UKR) is a validated, highly successful implant with an excellent ten-year survivorship. From November 2001 to September 2006 three hundred and eighty two patients who had a medial cemented Oxford Unicompartmental knee replacement (Biomet, Bridgend, UK) via a minimally invasive approach were prospectively entered into a database and followed up as per departmental policy in the specialist joint assessment clinic. We have noted a minority of patients have persistent postoperative pain and/or mechanical symptoms resistant to the standard postoperative therapies. We report the outcome of 22 patients who had an arthroscopy for persistent pain and/or mechanical symptoms a median of 15 months (range 4 months – 31 months) following medial unicompartmental knee replacement. The median follow up time following arthroplasty was 38 months (range 16 months – 63 months). Post arthroscopy we divided our study patients into two groups; those who had an improvement in symptoms and those who had none. These groups were then compared, with particular reference to demographics, check radiographs and arthroscopic findings. The results showed that patients with anterior or anteromedial symptoms in whom a medial rim of scar tissue was identified and debrided sixty seven percent had a significantly increased probability of symptomatic improvement (p<0.005). In addition men appeared to significantly improve more that women (p<0.043). When performed this therapeutic intervention many prevent or at least defer the need for early revision to total knee replacement in some cases and we have no complications as a result of the arthroscopic intervention. This observational study provides evidence for a role for arthroscopy in selected patients with pain following unicompartmental knee replacement.