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Bone & Joint Open
Vol. 5, Issue 10 | Pages 851 - 857
10 Oct 2024
Mouchantaf M Parisi M Secci G Biegun M Chelli M Schippers P Boileau P

Aims. Optimal glenoid positioning in reverse shoulder arthroplasty (RSA) is crucial to provide impingement-free range of motion (ROM). Lateralization and inclination correction are not yet systematically used. Using planning software, we simulated the most used glenoid implant positions. The primary goal was to determine the configuration that delivers the best theoretical impingement-free ROM. Methods. With the use of a 3D planning software (Blueprint) for RSA, 41 shoulders in 41 consecutive patients (17 males and 24 females; means age 73 years (SD 7)) undergoing RSA were planned. For the same anteroposterior positioning and retroversion of the glenoid implant, four different glenoid baseplate configurations were used on each shoulder to compare ROM: 1) no correction of the RSA angle and no lateralization (C-L-); 2) correction of the RSA angle with medialization by inferior reaming (C+M+); 3) correction of the RSA angle without lateralization by superior compensation (C+L-); and 4) correction of the RSA angle and additional lateralization (C+L+). The same humeral inlay implant and positioning were used on the humeral side for the four different glenoid configurations with a 3 mm symmetric 135° inclined polyethylene liner. Results. The configuration with lateralization and correction of the RSA angle (C+L+) led to better ROM in flexion, extension, adduction, and external rotation (p ≤ 0.001). Only internal rotation was not significantly different between groups (p = 0.388). The configuration where correction of the inclination was done by medialization (C+M+) led to the worst ROM in adduction, extension, abduction, flexion, and external rotation of the shoulder. Conclusion. Our software study shows that, when using a 135° inlay reversed humeral implant, correcting glenoid inclination (RSA angle 0°) and lateralizing the glenoid component by using an angled bony or metallic augment of 8 to 10 mm provides optimal impingement-free ROM. Cite this article: Bone Jt Open 2024;5(10):851–857


Bone & Joint Open
Vol. 5, Issue 10 | Pages 818 - 824
2 Oct 2024
Moroder P Herbst E Pawelke J Lappen S Schulz E

Aims

The liner design is a key determinant of the constraint of a reverse total shoulder arthroplasty (rTSA). The aim of this study was to compare the degree of constraint of rTSA liners between different implant systems.

Methods

An implant company’s independent 3D shoulder arthroplasty planning software (mediCAD 3D shoulder v. 7.0, module v. 2.1.84.173.43) was used to determine the jump height of standard and constrained liners of different sizes (radius of curvature) of all available companies. The obtained parameters were used to calculate the stability ratio (degree of constraint) and angle of coverage (degree of glenosphere coverage by liner) of the different systems. Measurements were independently performed by two raters, and intraclass correlation coefficients were calculated to perform a reliability analysis. Additionally, measurements were compared with parameters provided by the companies themselves, when available, to ensure validity of the software-derived measurements.


Bone & Joint Open
Vol. 5, Issue 9 | Pages 776 - 784
19 Sep 2024
Gao J Chai N Wang T Han Z Chen J Lin G Wu Y Bi L

Aims

In order to release the contracture band completely without damaging normal tissues (such as the sciatic nerve) in the surgical treatment of gluteal muscle contracture (GMC), we tried to display the relationship between normal tissue and contracture bands by magnetic resonance neurography (MRN) images, and to predesign a minimally invasive surgery based on the MRN images in advance.

Methods

A total of 30 patients (60 hips) were included in this study. MRN scans of the pelvis were performed before surgery. The contracture band shape and external rotation angle (ERA) of the proximal femur were also analyzed. Then, the minimally invasive GMC releasing surgery was performed based on the images and measurements, and during the operation, incision lengths, surgery duration, intraoperative bleeding, and complications were recorded; the time of the first postoperative off-bed activity was also recorded. Furthermore, the patients’ clinical functions were evaluated by means of Hip Outcome Score (HOS) and Ye et al’s objective assessments, respectively.


Bone & Joint Research
Vol. 13, Issue 9 | Pages 485 - 496
13 Sep 2024
Postolka B Taylor WR Fucentese SF List R Schütz P

Aims. This study aimed to analyze kinematics and kinetics of the tibiofemoral joint in healthy subjects with valgus, neutral, and varus limb alignment throughout multiple gait activities using dynamic videofluoroscopy. Methods. Five subjects with valgus, 12 with neutral, and ten with varus limb alignment were assessed during multiple complete cycles of level walking, downhill walking, and stair descent using a combination of dynamic videofluoroscopy, ground reaction force plates, and optical motion capture. Following 2D/3D registration, tibiofemoral kinematics and kinetics were compared between the three limb alignment groups. Results. No significant differences for the rotational or translational patterns between the different limb alignment groups were found for level walking, downhill walking, or stair descent. Neutral and varus aligned subjects showed a mean centre of rotation located on the medial condyle for the loaded stance phase of all three gait activities. Valgus alignment, however, resulted in a centrally located centre of rotation for level and downhill walking, but a more medial centre of rotation during stair descent. Knee adduction/abduction moments were significantly influenced by limb alignment, with an increasing knee adduction moment from valgus through neutral to varus. Conclusion. Limb alignment was not reflected in the condylar kinematics, but did significantly affect the knee adduction moment. Variations in frontal plane limb alignment seem not to be a main modulator of condylar kinematics. The presented data provide insights into the influence of anatomical parameters on tibiofemoral kinematics and kinetics towards enhancing clinical decision-making and surgical restoration of natural knee joint motion and loading. Cite this article: Bone Joint Res 2024;13(9):485–496


The Bone & Joint Journal
Vol. 106-B, Issue 9 | Pages 970 - 977
1 Sep 2024
De Rus Aznar I Ávila Lafuente JL Hachem A Díaz Heredia J Kany J Elhassan B Ruiz Ibán MÁ

Rotator cuff pathology is the main cause of shoulder pain and dysfunction in older adults. When a rotator cuff tear involves the subscapularis tendon, the symptoms are usually more severe and the prognosis after surgery must be guarded. Isolated subscapularis tears represent 18% of all rotator cuff tears and arthroscopic repair is a good alternative primary treatment. However, when the tendon is deemed irreparable, tendon transfers are the only option for younger or high-functioning patients. The aim of this review is to describe the indications, biomechanical principles, and outcomes which have been reported for tendon transfers, which are available for the treatment of irreparable subscapularis tears.

The best tendon to be transferred remains controversial. Pectoralis major transfer was described more than 30 years ago to treat patients with failed surgery for instability of the shoulder. It has subsequently been used extensively to manage irreparable subscapularis tendon tears in many clinical settings. Although pectoralis major reproduces the position and orientation of the subscapularis in the coronal plane, its position in the axial plane – anterior to the rib cage – is clearly different and does not allow it to function as an ideal transfer. Consistent relief of pain and moderate recovery of strength and function have been reported following the use of this transfer. In an attempt to improve on these results, latissimus dorsi tendon transfer was proposed as an alternative and the technique has evolved from an open to an arthroscopic procedure. Satisfactory relief of pain and improvements in functional shoulder scores have recently been reported following its use. Both pectoralis minor and upper trapezius transfers have also been used in these patients, but the outcomes that have been reported do not support their widespread use.

Cite this article: Bone Joint J 2024;106-B(9):970–977.


The Bone & Joint Journal
Vol. 106-B, Issue 9 | Pages 942 - 948
1 Sep 2024
Kingery MT Kadiyala ML Walls R Ganta A Konda SR Egol KA

Aims

This study evaluated the effect of treating clinician speciality on management of zone 2 fifth metatarsal fractures.

Methods

This was a retrospective cohort study of patients with acute zone 2 fifth metatarsal fractures who presented to a single large, urban, academic medical centre between December 2012 and April 2022. Zone 2 was the region of the fifth metatarsal base bordered by the fourth and fifth metatarsal articulation on the oblique radiograph. The proportion of patients allowed to bear weight as tolerated immediately after injury was compared between patients treated by orthopaedic surgeons and podiatrists. The effects of unrestricted weightbearing and foot and/or ankle immobilization on clinical healing were assessed. A total of 487 patients with zone 2 fractures were included (mean age 53.5 years (SD 16.9), mean BMI 27.2 kg/m2 (SD 6.0)) with a mean follow-up duration of 2.57 years (SD 2.64).


The Bone & Joint Journal
Vol. 106-B, Issue 9 | Pages 1008 - 1014
1 Sep 2024
Prijs J Rawat J ten Duis K Assink N Harbers JS Doornberg JN Jadav B Jaarsma RL IJpma FFA

Aims

Paediatric triplane fractures and adult trimalleolar ankle fractures both arise from a supination external rotation injury. By relating the experience of adult to paediatric fractures, clarification has been sought on the sequence of injury, ligament involvement, and fracture pattern of triplane fractures. This study explores the similarities between triplane and trimalleolar fractures for each stage of the Lauge-Hansen classification, with the aim of aiding reduction and fixation techniques.

Methods

Imaging data of 83 paediatric patients with triplane fractures and 100 adult patients with trimalleolar fractures were collected, and their fracture morphology was compared using fracture maps. Visual fracture maps were assessed, classified, and compared with each other, to establish the progression of injury according to the Lauge-Hansen classification.


The Bone & Joint Journal
Vol. 106-B, Issue 9 | Pages 898 - 906
1 Sep 2024
Kayani B Wazir MUK Mancino F Plastow R Haddad FS

Aims

The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system.

Methods

This study included 30 CO THAs versus 30 RO THAs performed by a single surgeon. Intraoperative photographs of the osseous acetabulum and periacetabular soft-tissues were obtained prior to implantation of the acetabular component, which were used to develop the proposed classification system. Interobserver and intraobserver variabilities of the proposed classification system were assessed.


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_16 | Pages 77 - 77
19 Aug 2024
Fu H Singh G H C Lam J Yan CH Cheung A Chan PK Chiu KY
Full Access

Hip precautions following total hip arthroplasty (THA) limits flexion, adduction and internal rotation, yet these precautions cause unnecessary psychological stress. This study aims to assess bony and implant impingement using virtual models from actual patient's bony morphology and spinopelvic parameters to deduce whether hip precautions are necessary with precise implant positioning in the Asian population. Individualized sitting and standing sacral slope data of robotic THAs performed at two tertiary referral centers in Hong Kong was inputted into the simulation system based on patients’ pre-operative sitting and standing lumbar spine X-rays. Three-dimensional dynamic models were reconstructed using the Stryker Mako THA 4.0 software to assess bony and implant impingement both anteriorly and posteriorly, with default cup placement at 40° inclination and 20° anteversion. Femoral anteversion followed individual patient's native version. A 36mm hip ball was chosen for all cups equal or above 48mm and 32mm for those below. Anterior impingement was assessed by hip flexion and posterior impingement was assessed by hip extension. 113 patients were included. At neutral rotation and adduction, no patients had anterior implant impingement at hip flexion of 100°. 1.7% had impingement at 110°, 3.5% had impingement at 120°, 9.7% had impingement at 130°. With 20° of internal rotation and adduction, 0.8% had anterior implant impingement at hip flexion of 90°, 7.1% had impingement at 100° and 18.5% had impingement at 110°. With the hip externally rotated by 20°, 0.8% of patients had posterior implant impingement, and 8.8% bony impingement at 0° extension. With enabling technology allowing accurate component positioning, hip precautions without limiting forward flexion in neutral position is safe given precise implant positioning and adequate osteophyte removal. Patients should only be cautioned about combined internal rotation, adduction with flexion


Bone & Joint Open
Vol. 5, Issue 8 | Pages 671 - 680
14 Aug 2024
Fontalis A Zhao B Putzeys P Mancino F Zhang S Vanspauwen T Glod F Plastow R Mazomenos E Haddad FS

Aims

Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement.

Methods

This international, multicentre prospective cohort study across two centres encompassed 157 adults undergoing primary robotic arm-assisted THA. Impingement during specific flexion and extension stances was identified using the virtual range of motion (ROM) tool of the robotic software. The primary AI model, the Light Gradient-Boosting Machine (LGBM), used tabular data to predict impingement presence, direction (flexion or extension), and type. A secondary model integrating tabular data with plain anteroposterior pelvis radiographs was evaluated to assess for any potential enhancement in prediction accuracy.


Bone & Joint 360
Vol. 13, Issue 4 | Pages 37 - 40
2 Aug 2024

The August 2024 Children’s orthopaedics Roundup360 looks at: Antibiotic prophylaxis and infection rates in paediatric supracondylar humerus fractures; Clinical consensus recommendations for the non-surgical treatment of children with Perthes’ disease in the UK; Health-related quality of life in idiopathic toe walkers: a multicentre prospective cross-sectional study; Children with spinal dysraphism: a systematic review of reported outcomes; No delay in age of crawling, standing, or walking with Pavlik harness treatment: a prospective cohort study; No value found with routine early postoperative radiographs after implant removal in paediatric patients; What do we know about the natural history of spastic hip dysplasia and pain in total-involvement cerebral palsy?; Evaluating the efficacy and safety of preoperative gallows traction for hip open reduction in infants


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_13 | Pages 10 - 10
17 Jun 2024
Malhotra K Patel S Cullen N Welck M
Full Access

Background. The cavovarus foot is a complex 3-dimensional deformity. Although a multitude of techniques are described for its surgical management, few of these are evidence based or guided by classification systems. Surgical management involves realignment of the hindfoot and soft tissue balancing, followed by forefoot balancing. Our aim was to classify the pattern of residual forefoot deformities once the hindfoot is corrected, to guide forefoot correction. Methods. We included 20 cavovarus feet from adult patients with Charcot-Marie-Tooth who underwent weightbearing CT (mean age 43.4 years, 14 males). Patients included had flexible deformities, with no previous surgery. Previous work established majority of rotational deformity in cavovarus feet occurs at the talonavicular joint, which is often reduced during surgery. Using specialised software (Bonelogic 2.1, Disior) a 3-dimensional, virtual model was created. Using data from normal feet as a guide, the talonavicular joint of the cavovarus feet was digitally reduced to a ‘normal’ position. Models of the corrected position were exported and geometrically analysed using Blender 3.6 to identify anatomical trends. Results. We identified 3 types of cavovarus forefoot morphotypes. Type 1 was seen in 13 cases (65%) and was defined as a foot where only the first metatarsal was relatively plantarflexed to the rest of the foot, with no significant residual adduction after talonavicular correction. Type 2 was seen in 4 cases (20%) and was defined as a foot where the second and first metatarsals were progressively plantarflexed, with no significant adduction. Type 3 was seen in 3 cases (15%) and was defined as a foot where the metatarsals were still adducted after talonavicular de-rotation. Conclusion. We classify 3 forefoot morphotypes in cavovarus feet. It is important to recognise and anticipate the residual forefoot deformities after hindfoot correction as different treatment strategies may be required for different morphotypes to achieve balanced correction


The Bone & Joint Journal
Vol. 106-B, Issue 5 Supple B | Pages 32 - 39
1 May 2024
Briem T Stephan A Stadelmann VA Fischer MA Pfirrmann CWA Rüdiger HA Leunig M

Aims

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI).

Methods

This single-centre study focused on a cohort of 24 patients with cam- or pincer-type FAI, full-thickness femoral or acetabular chondral lesions, or osteochondral lesions ≥ 2 cm2, who underwent surgical hip dislocation for FAI correction in combination with AMIC between March 2009 and February 2016. Baseline data were retrospectively obtained from patient files. Mid-term outcomes were prospectively collected at a follow-up in 2020: cartilage repair tissue quality was evaluated by MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported outcome measures (PROMs) included the Oxford Hip Score (OHS) and Core Outcome Measure Index (COMI). Clinical examination included range of motion, impingement tests, and pain.


The Bone & Joint Journal
Vol. 106-B, Issue 5 Supple B | Pages 40 - 46
1 May 2024
Massè A Giachino M Audisio A Donis A Giai Via R Secco DC Limone B Turchetto L Aprato A

Aims

Ganz’s studies made it possible to address joint deformities on both the femoral and acetabular side brought about by Perthes’ disease. Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency, along with periacetabular osteotomy (PAO), which may enhance coverage and containment. The purpose of this study is to show the clinical and morphological outcomes of the technique and the use of an implemented planning approach.

Methods

From September 2015 to December 2021, 13 FHROs were performed on 11 patients for Perthes’ disease in two centres. Of these, 11 hips had an associated PAO. A specific CT- and MRI-based protocol for virtual simulation of the corrections was developed. Outcomes were assessed with radiological parameters (sphericity index, extrusion index, integrity of the Shenton’s line, lateral centre-edge angle (LCEA), Tönnis angle), and clinical parameters (range of motion, visual analogue scale (VAS) for pain, Merle d'Aubigné-Postel score, modified Harris Hip Score (mHHS), and EuroQol five-dimension five-level health questionnaire (EQ-5D-5L)). Early and late complications were reported.


The Bone & Joint Journal
Vol. 106-B, Issue 4 | Pages 352 - 358
1 Apr 2024
Wilson JM Trousdale RT Bedard NA Lewallen DG Berry DJ Abdel MP

Aims

Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct.

Methods

We identified 64 patients (65 hips) who had a single-design cemented DM cup cemented into an uncemented acetabular shell during revision THA between 2018 and 2020 at our institution. Cups were cemented into either uncemented cups designed for liner cementing (n = 48; 74%) or retained (n = 17; 26%) acetabular components. Median outer head diameter was 42 mm. Mean age was 69 years (SD 11), mean BMI was 32 kg/m2 (SD 8), and 52% (n = 34) were female. Survival was assessed using Kaplan-Meier methods. Mean follow-up was two years (SD 0.97).


The Bone & Joint Journal
Vol. 106-B, Issue 3 Supple A | Pages 59 - 66
1 Mar 2024
Karunaseelan KJ Nasser R Jeffers JRT Cobb JP

Aims

Surgical approaches that claim to be minimally invasive, such as the direct anterior approach (DAA), are reported to have a clinical advantage, but are technically challenging and may create more injury to the soft-tissues during joint exposure. Our aim was to quantify the effect of soft-tissue releases on the joint torque and femoral mobility during joint exposure for hip resurfacing performed via the DAA.

Methods

Nine fresh-frozen hip joints from five pelvis to mid-tibia cadaveric specimens were approached using the DAA. A custom fixture consisting of a six-axis force/torque sensor and motion sensor was attached to tibial diaphysis to measure manually applied torques and joint angles by the surgeon. Following dislocation, the torques generated to visualize the acetabulum and proximal femur were assessed after sequential release of the joint capsule and short external rotators.


The Bone & Joint Journal
Vol. 106-B, Issue 3 Supple A | Pages 17 - 23
1 Mar 2024
LaValva SM LeBrun DG Canoles HG Ren R Padgett DE Su EP

Aims

Professional dancers represent a unique patient population in the setting of hip arthroplasty, given the high degree of hip strength and mobility required by their profession. We sought to determine the clinical outcomes and ability to return to professional dance after total hip arthroplasty (THA) or hip resurfacing arthroplasty (HRA).

Methods

Active professional dancers who underwent primary THA or HRA at a single institution with minimum one-year follow-up were included in the study. Primary outcomes included the rate of return to professional dance, three patient-reported outcome measures (PROMs) (modified Harris Hip Score (mHHS), Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), and Lower Extremity Activity Scale (LEAS)), and postoperative complications.


The Bone & Joint Journal
Vol. 106-B, Issue 2 | Pages 128 - 135
1 Feb 2024
Jenkinson MRJ Cheung TCC Witt J Hutt JRB

Aims

The aim of this study is to evaluate whether acetabular retroversion (AR) represents a structural anatomical abnormality of the pelvis or is a functional phenomenon of pelvic positioning in the sagittal plane, and to what extent the changes that result from patient-specific functional position affect the extent of AR.

Methods

A comparative radiological study of 19 patients (38 hips) with AR were compared with a control group of 30 asymptomatic patients (60 hips). CT scans were corrected for rotation in the axial and coronal planes, and the sagittal plane was then aligned to the anterior pelvic plane. External rotation of the hemipelvis was assessed using the superior iliac wing and inferior iliac wing angles as well as quadrilateral plate angles, and correlated with cranial and central acetabular version. Sagittal anatomical parameters were also measured and correlated to version measurements. In 12 AR patients (24 hips), the axial measurements were repeated after matching sagittal pelvic rotation with standing and supine anteroposterior radiographs.


Bone & Joint Research
Vol. 12, Issue 12 | Pages 712 - 721
4 Dec 2023
Dantas P Gonçalves SR Grenho A Mascarenhas V Martins J Tavares da Silva M Gonçalves SB Guimarães Consciência J

Aims

Research on hip biomechanics has analyzed femoroacetabular contact pressures and forces in distinct hip conditions, with different procedures, and used diverse loading and testing conditions. The aim of this scoping review was to identify and summarize the available evidence in the literature for hip contact pressures and force in cadaver and in vivo studies, and how joint loading, labral status, and femoral and acetabular morphology can affect these biomechanical parameters.

Methods

We used the PRISMA extension for scoping reviews for this literature search in three databases. After screening, 16 studies were included for the final analysis.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_16 | Pages 35 - 35
17 Nov 2023
Timme B Biant L McNicholas M Tawy G
Full Access

Abstract. Objectives. Little is known about the impact of cartilage defects on knee joint biomechanics. This investigation aimed to determine the gait characteristics of patients with symptomatic articular cartilage lesions of the knee. Methods. Gait analyses were performed at the Regional North-West Joint Preservation Centre. Anthropometric measurements were obtained, then 16 retroreflective markers representing the Plug-in-Gait biomechanical model were placed on pre-defined anatomical landmarks. Participants walked for two minutes at a self-selected speed on a treadmill on a level surface, then for 2 minutes downhill. A 15-camera motion-capture system recorded the data. Knee kinematics were exported into Matlab to calculate the average kinematics and spatiotemporal parameters per patient across 20 gait cycles. Depending on the normality of the data, paired t-tests or Wilcoxon ranked tests were performed to compare both knees (α = 0.05). Results. 20 patients participated; one of whom has bilateral cartilage defects. All 20 data sets were analysed for level walking; 18 were analysed for downhill walking. On a level surface, patients walked at an average speed of 3.1±0.8km/h with a cadence of 65.5±15.3 steps/minute. Patients also exhibited equal step lengths (0.470±0.072m vs 0.471±0.070m: p=0.806). Downhill, the average walking speed was 2.85±0.5km/h with a cadence of 78.8±23.1 steps/minute and step lengths were comparable (0.416±0.09m vs 0.420±0.079m: p=0.498). During level walking, maximum flexion achieved during swing did not differ between knees (54.3±8.6° vs 55.5±11.0°:p=0.549). Neither did maximal extension achieved at heel strike (3.1±5.7° vs 5.4±4.7°:p=0.135). On average, both knees remained in adduction throughout the gait cycle, with the degree of adduction greater in flexion in the operative knee. However, differences in maximal adduction were not significant (22.4±12.4° vs 18.7±11.0°:p=0.307). Maximal internal-external rotation patterns were comparable in stance (0.9±7.7° vs 3.5±9.8°: p=0.322) and swing (7.7±10.9° vs 9.8±8.3°:p=0.384). During downhill walking, maximum flexion also did not differ between operative and contralateral knees (55.38±10.6° vs 55.12±11.5°:p=0.862), nor did maximum extension at heel strike (1.32±6.5° vs 2.73±4.5°:p=0.292). No significant difference was found between maximum adduction of both knees (15.87±11.0° vs 16.78±12.0°:p=0.767). In stance, differences in maximum internal-external rotation between knees were not significant (5.39±10.7° vs 6.10±11.8°:p=0.836), nor were they significant in swing (7.69±13.3° vs 7.54±8.81°:p=0.963). Conclusions. Knee kinematics during level and downhill walking were symmetrical in patients with a cartilage defect of the knee, but an increased adduction during flexion in the operative knee may lead to pathological loading across the medial compartment of the knee during high flexion activities. Future work will investigate this further and compare the data to a healthy young population. We will also objectively assess the functional outcome of this joint preservation surgery to monitor its success. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project