Aims. The aim of this study was to compare the incidence of anterior knee pain after antegrade tibial nailing using suprapatellar and infrapatellar surgical approaches. Patients and Methods. A total of 95 patients with a tibial fracture requiring an intramedullary nail were randomized to treatment using a supra- or infrapatellar approach. Anterior knee pain was assessed at four and six months, and one year postoperatively, using the Aberdeen Weightbearing Test – Knee (AWT-K) score and a visual analogue scale (VAS) score for pain. The AWT-K is an objective patient-reported outcome measure that uses weight transmitted through the knee when kneeling as a surrogate for anterior knee pain. Results. A total of 53 patients were randomized to a suprapatellar approach and 42 to an infrapatellar approach. AWT-K results showed a greater mean proportion of weight transmitted through the injured leg compared with the uninjured leg when kneeling in the suprapatellar group compared with the infrapatellar group at all timepoints at all follow-up visits. This reached significance at four months for all timepoints except 30 seconds. It also reached significance at six months at 0 seconds, and for one year at 60 seconds. Conclusion. The suprapatellar surgical approach for antegrade tibial nailing is associated with less anterior knee pain postoperatively compared with the infrapatellar approach. Cite this article: Bone Joint J 2019;101-B:1138–1143

Objectives. To assess the effectiveness of a modified tibial tubercle osteotomy as a treatment for arthroscopically diagnosed chondromalacia patellae. Methods. A total of 47 consecutive patients (51 knees) with arthroscopically proven chondromalacia, who had failed conservative management, underwent a modified Fulkerson tibial tubercle osteotomy. The mean age was 34.4 years (19.6 to 52.2). Pre-operatively, none of the patients exhibited signs of patellar maltracking or instability in association with their anterior knee pain. The minimum follow-up for the study was five years (mean 72.6 months (62 to 118)), with only one patient lost to follow-up. Results. A total of 50 knees were reviewed. At final follow-up, the Kujala knee score improved from 39.2 (12 to 63) pre-operatively to 57.7 (16 to 89) post-operatively (p < 0.001). The visual analogue pain score improved from 7.8 (4 to 10) pre-operatively to 5.0 (0 to 10) post-operatively. Overall patient satisfaction with good or excellent results was 72%. Patients with the lowest pre-operative Kujala score benefitted the most. Older patients benefited less than younger ones. The outcome was independent of the grade of chondromalacia. Six patients required screw removal. There were no major complications. Conclusions. We conclude that this modification of the Fulkerson procedure is a safe and useful operation to treat anterior knee pain in well aligned patellofemoral joints due to chondromalacia patellae in adults, when conservative measures have failed

Our purpose was to evaluate the incidence of anterior knee pain after ACL reconstruction and the associated affecting factors. The study assessed 50 ACL reconstructed knees: 29 males and 21 females. The age at surgery was from 14 to 39 years old, with 23.7 years old on the average. The ACL injury was unilateral in all cases, and the normal side was defined as the control. We treated chronic ACL-deficient knees by reconstruction of the ligament through a limited arthrotomy using one-third of the patellar tendon (BTB) with the Kennedy LAD as a graft. Anterior knee pain was classified into 4 group: absent, trace-mild, moderate, and severe. We evaluated the height of the patella, knee extension strength, anterior laxity, leg rotation, Lysholm score, and loss of extension. Anterior laxity and leg rotation were measured by a three-dimensional analyzer. Ten of the fifty knees (20%) had anterior knee pain. Knee extension strength (reconstructed side/control side) was 71.1% in the cases with anterior knee pain and 84.2% in the cases without anterior knee pain. A significant difference was found between these values. Regarding leg rotation, 4 knees showed normal leg rotation (physiological screw home movement) in the cases with anterior knee pain, compared to 31 knees in the cases without anterior knee pain. There was a significant difference in the incidence of anterior knee pain between the cases with normal leg rotation and the cases without. Other factors failed to show any significant correlation. In this study, knee extension strength and leg rotation had a correlation with anterior knee pain

Aims. It is not clear whether anterior knee pain and osteoarthritis (OA) of the patellofemoral joint (PFJ) are contraindications to medial unicompartmental knee arthroplasty (UKA). Our aim was to investigate the long-term outcome of a consecutive series of patients, some of whom had anterior knee pain and PFJ OA managed with UKA. Patients and Methods. We assessed the ten-year functional outcomes and 15-year implant survival of 805 knees (677 patients) following medial mobile-bearing UKA. The intra-operative status of the PFJ was documented and, with the exception of bone loss with grooving to the lateral side, neither the clinical or radiological state of the PFJ nor the presence of anterior knee pain were considered a contraindication. The impact of radiographic findings and anterior knee pain was studied in a subgroup of 100 knees (91 patients). Results. There was no relationship between functional outcomes, at a mean of ten years, or 15-year implant survival, and pre-operative anterior knee pain, or the presence or degree of cartilage loss documented intra-operatively at the medial patella or trochlea, or radiographic evidence of OA in the medial side of the PFJ. In 6% of cases there was full thickness cartilage loss on the lateral side of the patella. In these cases, the overall ten-year function and 15-year survival was similar to those without cartilage loss; however they had slightly more difficulty with descending stairs. Radiographic signs of OA seen in the lateral part of the PFJ were not associated with a definite compromise in functional outcome or implant survival. Conclusion. Severe damage to the lateral side of the PFJ with bone loss and grooving remains a contraindication to mobile-bearing UKA. Less severe damage to the lateral side of the PFJ and damage to the medial side, however severe, does not compromise the overall function or survival, so should not be considered to be a contraindication. However, if a patient does have full thickness cartilage loss on the lateral side of the PFJ they may have a slight compromise in their ability to descend stairs. Pre-operative anterior knee pain also does not compromise the functional outcome or survival and should not be considered to be a contraindication. Cite this article: Bone Joint J 2017;99-B:632–9

Introduction. Up to 15 % of patients report anterior knee pain (AKP) after a total knee arthroplasty (TKA). The correlation of radiographic patellar measurements and post-operative AKP remains controversial. The purpose of this study was to determine whether any radiographic measurements can predict anterior knee pain after TKA. Methods. We performed a retrospective analysis of data on 343 patients who underwent a primary unilateral TKA between 2009–2012 at a single institution. Post-operative radiographs were evaluated with standing anteroposterior, lateral, and merchant views. Radiographic assessment was performed to assess posterior offset, Insall Salvati ratio, Blackburne, PP angle, Patella thickness, Congruence angle, Patella tilt, and patella displacement. Clinical function was assessed by the Kujala anterior knee pain scale at a minimum of 5 years. Patients were asked if they currently had anterior knee pain post-operatively by responding “yes” or “no.” There were 264 females and 79 males; the mean age at surgery was 64.2 ± 9.7 (range, 42–92 years) years; the mean BMI 31±5.8 kg/m. 2. (range, 18.8–49 kg/m. 2. ). Results. Of the 343 patients, 46 patients (13.4%) patients suffered persistent AKP at a minimum 5 years follow-up. Radiographic measurements were performed. Although we had large variations in congruence angle, patellar tilt and patellar displacement, these variations had no correlation with anterior knee pain (p=0.885). We were not able to detect statistical significance among clinical outcome Kujala score and patient reported AKP (p=0.713) at minimum 5 year follow-up. Discussion. Persistent anterior knee pain is troubling to patients and surgeons. Clinicians often get concerned when they see variability in these radiographic findings. Our findings suggest that variations in radiographic parameters do not predict anterior knee pain following total knee replacement surgery. For figures, tables, or references, please contact authors directly

There is a recognised incidence of anterior knee pain following Anterior Cruciate Ligament (ACL) reconstruction using a patella tendon autograft. This study examined two group of patients both pre ACL ligament reconstruction and post ACL reconstruction using patella tendon grafts to define if anterior knee pain is a result of patella tendon harvest or a primary consequence of an ACL injury. The two groups of patients were best matched for age, sex and physical activity. The pre-operative group of twenty-five patients had a confirmed ACL rupture and exhibited symptoms of instability requiring an ACL reconstruction. The operative group of twenty-five patients were a minimum of a year post operation. The graft was harvested by an open procedure and the graft bone blocks were secured with interference screws. The patients’ anterior knee pain score was assessed using the Shelbourne scoring system that evaluates knee function in relation to anterior knee pain using five parameters. The maximum score is 100. The scores were compared using the unpaired student test. There was no significant age difference between the two groups, preoperative group age 32. 2 years (range 22 to 46) and postoperative age 34. 8years (range 19 to 48). The mean anterior knee pain score for the preoperative group was 71. 6 (49 to 100), the postoperative group was 77. 7 (45 to 100), this was not significantly different. We found no significant difference in knee function due to anterior knee pain between the two groups. Studies have shown significant anterior knee pain following hamstring reconstruction (Spicer). This study shows anterior knee pain in the ACL deficient knee is present prior to surgery. We conclude that patella tendon autografts produce no significant incidence of anterior knee pain post surgery

Anterior knee pain is a frequent complaint of dissatisfied total knee arthroplasty patients. We hypothesize that the need to use the extensor mechanism to stabilise the knee during activity is a cause of anterior knee pain. Studies have shown that TKA patients often walk with a “quadriceps avoidance” gait, which may explain the phenomenon of anterior knee pain. Most TKA prostheses are designed to allow AP motion. This feature in knee implant design is to prevent the “kinematic conflict” that was predicted with the crossed four-bar-link model of knee motion, which holds that progressive posterior contact of the femur on the tibia (rollback) with flexion was obligatory for knee range of motion. It has been stated that preventing this motion overly “constrained” the knee and could lead to loosening and wear. Paradoxical motion has been seen with video fluoroscopy in knees after TKA. This motion is an anterior translation of the femur on the tibia early in knee flexion and is called paradoxical because it occurs opposite to the expected rollback. In fact, paradoxical motion is a consequence of the “unconstrained” articulation of the femoral component on the tibial component. During gait, just after heel strike as the foot is assuming a flat position on the floor, there is a significant vector of force from posterior to anterior. This vector has been calculated as 33% of body weight for walking at normal speed and could lead to a significant displacement of the femur forward on the tibia. It is countered by 1) the slope of the proximal tibia; 2) the articulation of the femur in the concavity of the tibial (with the firmly attached meniscus that deepens the concavity) on the medial side; and 3) the body mass vector combined with that of the contracting quadriceps. If a total knee prosthesis allows the femur to move forward, the posterior-to-anterior force just after heel strike acts to move the femur forward on the tibia (paradoxical motion). The patient, in an attempt to stabilise the knee, uses increased quadriceps contraction to prevent the forward motion of the femur. The forces required are significant and are not only found in the patella-femoral articulation but all through the retinaculum that covers the anterior part of the femur. As the extensor mechanism tires, patients begin using a quadriceps avoidance gait to adapt to the weakening extensor, and after a period of activity, the stress on the retinaculum leads to pain. AP stability can be improved through implant design by preventing AP motion through conformity of the femoral and tibial components. We have used a medially conforming ball-in-socket prosthesis as a revision component for patients with anterior knee pain, and have achieved resolution of the pain. Patients demonstrate a “posterior sag” at approximately 20 degrees of flexion (the degree of flexion that has the maximum posterior-to-anterior force during gait). When treated with a brace appropriate for stabilisation of the knee after PCL reconstruction, patients experienced a marked decrease in symptoms and this predicts a good result from revision surgery

Excessive foot pronation has been considered to be related to anterior knee pain. We undertook a prospective study to test the hypothesis that exertional anterior knee pain is related to the static and dynamic parameters of foot pronation. Two weeks before beginning basic training lasting for 14 weeks, 473 infantry recruits were enrolled into the study and underwent two-dimensional measurement of their subtalar joint displacement angle during walking on a treadmill. Of the 405 soldiers who finished the training 61 (15%) developed exertional anterior knee pain. No consistent association was found between the incidence of anterior knee pain and any of the parameters of foot pronation. While a statistically significant association was found between anterior knee pain and pronation velocity (left foot, p = 0.05; right foot, p = 0.007), the relationship was contradictory for the right and left foot. Our study does not support the hypothesis that anterior knee pain is related to excessive foot pronation

Purpose: A relationship between vastus medialis oblique (VMO) strength and anterior pain and disability has been suggested. A biomechanical protocol was used to access the deficiency of the quadriceps muscles in patients with anterior knee pain. Methods and Results: A biomechanical evaluation was conducted on 54 patients with anterior knee pain (34 females and 20 males). All patient x-rays were normal through interpretation by a blinded radiologist. A Kistler force plate, a VICON motion analysis system and surface electromyography were used to quantify biomechanical function during isometric, walking and squatting exercises. For 42 of the 54 (78%) subjects, during isometric and walking exercises we observed that activation of the VMO, rectus femoris (RF) and vastus lateralis (VL) muscles of the symptomatic leg was not significantly different from those of the asymptomatic leg (p< 0.01). However, for 31 patients (57%) during the eccentric phase of the squat exercises, the symptomatic leg presented with high activation of VL compared to VMO and RF (p< 0.01). During the concentric phase, 45 patients (83%) presented with higher activation of the VL compared to the VMO. Conclusion: VMO activity during squatting for the symptomatic patient with anterior knee pain leg differs fundamentally during walking and isometric exercise compared to squatting tasks. Moreover, the relative contribution of the VL compared to the VMO during the eccentric phase of the squat exercises was different to those recorded during the concentric phase. Therefore, we suggest that maximal isometric and or isokinetic exercises are not sufficient to access the quadriceps function in relation to anterior knee pain. A thorough biomechanical assessment, including functional testing to reproduce the patient’s pain and locate the nature of the symptoms is suggested

Aim: To assess the prevalence of anterior knee pain after intramedullary nailing of the tibia and its socioeconomic impact. Methods: A retrospective, study of 251 consecutive tibial intramedullary nailings in 248 patients, aged less than 60 years at the time of injury. The minimum follow-up period was five years and the patients were assessed using a questionnaire and the Lysholm knee score. Results: The mean follow-up was 7.9 years. Anterior knee sensory disturbance was reported by 58% of patients. Anterior knee pain (AKP) was reported by 47%. This interfered with activities of daily living in 37%, work in 36% and sport in 57%. Pain on kneeling was mild in 54%, moderate in 34% and severe 12%. AKP improved with time in 73% patients and became worse in 4%. The Lysholm score rated 41% knees as excellent, 19% as good, 26% as fair and 14% as poor. Eighty-six percent of the patients returned to work. The presence of anterior knee pain prevented return to previous work in 10%. The type of work performed before and after injury respectively were; sedentary 26%/29%, walking-based 20%/27%, manual 38%/37%, heavy manual 16%/7%. Conclusions: Anterior knee pain persisted in 47% of patients after intramedullary nailing of the tibia. There was some decrease in symptoms with time and the majority of patients were able to return to work. However, anterior knee pain caused a significant disability in a small number and all patients should be warned of this problem before this type of surgery

Aims: Anterior knee pain is a common complaint of mixed aetiology, and in many cases no demonstrable cause is identified. For patients with persistant anterior knee pain, tibial tubercle transfer (TTT) can be a surgical option. The aim of this study is to assess the effectiveness of TTT for chronic anterior knee pain resistant to conservative treatment. Method: All patients with arthroscopically proven Chondromalacia patellae (CMP) without clinical evidence of patella instability, who have failed to respond to conservative treatment such as physiotherapy were included in the trial. They underwent TTT with a modified Fulkerson technique and then routine post-operative care with a cricket pad splint for 2–4 weeks. Pre and post-operative scores were obtained using a Kujala patello-femoral score, a visual analogue score for pain and a patient satisfaction score. The Outerbridge grading was used to score the severity of CMP at arthroscopy. Results: There were 50 TTT’s followed up (7 staged bilaterals) with a mean follow up of 32.4 months (5–88 months). There were significant improvement in the pre-operative and post-operative Kujala (p> 0.001) and visual analogue pain scores (p> 0.001). Of the 50 TTT’s 70% had an excellent or good result and 30% a fair or poor result. Moreover 76% claimed that they would have the same operation again for their condition. There was no significant correlation between Outerbridge grading and post-operative outcome. Complications include late anterior knee pain (10 cases), superficial wound infection (1 case), non-union of osteotomy (1 case) and tuberosity fracture (1 case). Conclusion: Anteromedial tibial tubercle transfer is a reliable and effective treatment for peristant anterior knee pain

The purpose of this study was to test the hypothesis that patella alta leads to a less favourable situation in terms of patellofemoral contact force, contact area and contact pressure than the normal patellar position, and thereby gives rise to anterior knee pain. A dynamic knee simulator system based on the Oxford rig and allowing six degrees of freedom was adapted in order to simulate and record the dynamic loads during a knee squat from 30° to 120° flexion under physiological conditions. Five different configurations were studied, with variable predetermined patellar heights. The patellofemoral contact force increased with increasing knee flexion until contact occurred between the quadriceps tendon and the femoral trochlea, inducing load sharing. Patella alta caused a delay of this contact until deeper flexion. As a consequence, the maximal patellofemoral contact force and contact pressure increased significantly with increasing patellar height (p < 0.01). Patella alta was associated with the highest maximal patellofemoral contact force and contact pressure. When averaged across all flexion angles, a normal patellar position was associated with the lowest contact pressures. Our results indicate that there is a biomechanical reason for anterior knee pain in patients with patella alta

Introduction. Special high-flexion prosthetic designs show a small increase in postoperative flexion compared to standard designs and some papers show increased anterior knee pain with these prosthesis. However, no randomised controlled trails have been published which investigate difference in postoperative complaints of anterior knee pain. To assess difference in passive and active postoperative flexion and anterior knee pain we performed a randomized clinical trial including the two extremes of knee arthroplasty designs, being a high flex posterior stabilized rotating platform prosthesis versus a traditional cruciate retaining fixed bearing prosthesis. We hypothesised that the HF-PS design would allow more flexion, due to increased femoral rollback with less anterior knee pain than the CR design. We specifically assessed the following hypotheses:. Patients have increased flexion after HF-PS TKA compared to CR TKA, both passive and active. Patients show an increased femoral rollback in the HF-PS TKA as compared to the CR TKA. Patients receiving a HF-PS TKA design report reduced anterior knee pain relative to those receiving the CR TKA. Methods. In total 47 patients were randomly allocated to a standard cruciate retaining fixed bearing design (CR) in 23 patients and to a high-flexion posterior stabilized mobile bearing design (HF-PS) in 24 patients. Preoperative and one year postoperative we investigated active and passive maximal flexion. Furthermore, we used the VAS pain score at rest and during exercise and the Feller score to investigate anterior knee pain. A lateral roentgen photograph was used to measure femoral rollback during maximal flexion. Results. The HF-PS did show a significantly higher passive postoperative flexion; 120.8° (SD 10.3°) vs. 112.0° (SD 9.5°) for the CR group (p=0.004). The active postoperative flexion, VAS-pain score and Feller score did not show significant differences between both groups. Sub analysis with the HF-PS group showed a higher VAS-pain for the patients achieving ≥130° of flexion; 30.5 (SD 32.2) vs. 12.2 (SD 12.5) (p=0.16). The rollback was significantly lower in the CR group compared to the HF-PS group; 4.4 (SD 3.0) vs. 8.4 (SD 2.1). Conclusion. The present study showed a significant higher passive flexion in the Posterior Stabilised-High Flexion mobile bearing compared to a Cruciate Retaining fixed bearing prosthesis. However, this difference disappeared when comparing active flexion. The difference in passive flexion was probably related to a significantly lower rollback causing impingement in the CR prosthesis. No difference in anterior knee pain was found between both groups. However, a suggestion is raised that achieving high-flexion might lead to more patellofemoral complaints/anterior knee pain

Achieving deep flexion of knee after total knee arthroplasty (TKA) is particularly desirable in some Asian and Middle Eastern who have daily or religious customs typically use full knee flexion. After TKA, some patients complained about anterior knee pain during deep knee flexion. We evaluated the efficacy of arthroscopic fat pad resection in a series of patients suffering from anterior knee pain associated with high flexion achievement after TKA. The efficacy of fat pad resection via arthroscopy for treating anterior knee pain associated with high flexion angle (average = 133.1°) was evaluated in eight knees of eight patients among 207 knees performed between 1996 and 1999. The mean age of patients was 71.1 years when the primary TKA was performed. All implatants were posterior stabilized type (IB-II, Nexgen PS and LPS). The symptom of anterior knee pain during deep knee flexion developed within one year after TKA in all cases. In addition to pain in eight knees, two patients have crepitation as the knee was flexed and extended and three patients had hydrarthrosis. Impingement and fibrosis of fat pad were confirmed, and fibrous structures were removed by arthroscopy. Before arthroscopy, the symptom obviously subsided after injection of local anesthesia into infrapatellar fat pad. Patellar clunk syndrome is also soft tissue impingement and suprapatellar fibrous nodule becomes entrapped intercondylar notch on the femoral component during knee flexion. On this point, these cases does not cause by patellar clunk syndrome. After fat pad resection, the symptom disappeared, and keeps symptom-free after a mean follow-up of six years five months in all cases. Any complications following fat pad resection, such as patella baja and necrosis, were not experienced. Those cases achieving higher flexion angle tended to experience severe pain and shorter time interval between TKA and arthroscopic surgery, suggesting impingement of the infrapatellar fat pad is closely related to deep flexion after TKA. These results demonstrate that the anterior knee pain due to repetitive infrapatellar fat pad impingement is one of the complications during deep knee flexion after TKA, and the arthroscopic fat pad resection is useful to relief the anterior knee pain. Because of our experience with patients encountering anterior knee pain, we have begun to remove 70 to 80% of the fat pad during the primary TKA procedure since 1999, and until today, none developed anterior knee pain thought to be associated with fat pad impingement, patellar baja nor patellar necrosis. We suggest that fat pad resection is necessary to prevent the anterior knee pain due to fat pad impingement during deep flexion in TKA

The prevalence of anterior knee pain in the general population is relatively high. Patellar height, and more specific patella alta, is one of the several factors that have been associated with anterior knee pain, but the precise mechanism by which patella alta leads to a less favourable situation in terms of patellofemoral contact force, contact area and contact pressure, is poorly understood. The recent availability of validated dynamic knee simulators and advances in the analysis of contact force and area, give us today the possibility to study the influence of patellar position and patellar height on patellofemoral biomechanical characterisitics. Simulating a knee squat in different configurations with variable predetermined patellar height, reveals a clear association of patella alta with the highest maximal patellofemoral contact force and contact pressure, probably as a consequence of the delay in tendofemoral contact. When averaged across all flexion angles, the normal height of the patella seems to be the most optimal position in terms of contact pressures. This may provide a biomechanical explanation for anterior knee pain in young patients with patella alta and in older patients following total knee prosthesis resulting in an altered patellar position in terms of height

The aim of this study was to assess the outcome of patients who underwent ElmslieTrillat antero-medial tibial tubercle transfer for treatment of persistent symptomatic anterior knee pain due to chondromalacia patellae. We performed a prospective analysis of 23 patients who underwent Elmslie-Trillat antero-medial tibial tubercle transfers over a five year period for chronic anterior knee pain and an arthroscopic diagnosis of chondromalacia patellae. All patients who presented with anterior knee pain underwent an initial period of physiotherapy and all patients whose symptoms persisted following physiotherapy underwent arthroscopic assessment. Patients who continued to experience debilitating symptoms despite this initial treatment and who also had a diagnosis of chondromalacia patellae from arthroscopic assessment were listed for an Elmslie-Trillat tibial tubercle anteromedialisation. Patients who gave a history of instability or dislocation were excluded. The average age of patients undergoing surgery was 34 years (21–48 years) and the average time between arthroscopic diagnosis and surgery was 14 months. All patients who underwent surgery had pre and post operative KuJala patellofemoral scoring. The average pre-operative score was 54 (30–78) and post operative score 76 (46–100). The average post operative assessment was 25 months (6–62 months). Twenty one patients had improved post operative scores with one having a worse score and one score remaining unchanged following surgery. Nineteen patients felt that their symptoms had improved, three felt that there had been no change and one felt that they were worse after surgery. When asked if the improvement in symptoms had been worthwhile nineteen stated that they would undergo surgery again if in the same situation and four stated that they would not. The treatment of symptomatic chondromalacia patellae remains a challenge. Although a more selective approach to individuals with anterior knee pain is widely advocated in the literature this study demonstrates that good results can still be achieved in patients treated empirically with a tibial tubercle anteromedialisation

Total knee arthroplasty (TKA) disturbs patellar blood flow, an unintended accompaniment to TKA that may be a cause for postoperative anterior knee pain. We compared patellar blood flow before and after medial parapatellar arthrotomy to pre- and postoperative anterior knee pain scores to ascertain whether disrupted patellar blood flow correlates with anterior knee pain following TKA. Blood flow measurements were performed at full extension and at 30°, 60°, 90° and 110° of flexion prior to and after medial arthrotomy in 50 patients (21 male, 29 female; mean age 73.1±8.6 years) undergoing TKA. Anterior knee pain was assessed using the pain intensity numeric rating scale. A significant decrease in blood flow was detected at 60°, 90°, and 110° of flexion (p values: 0.00314,< 0.0001,< 0.0001 respectively). The medial arthrotomy did not have a statistically significant influence on patellar blood flow in the Students’ t-test (margin of significance p& #61603;0.05) Nineteen patients exhibited an average 14% (range 1%–54%) increase in patellar blood perfusion at knee flexions of 90° and 110° after medial arthrotomy (p value: 0.32) Prior to TKA, 16 of the 50 patients (32%) complained of anterior knee pain (average NRS 7.12, range 5–10). At 6-month follow up, 4 of the 16 patients (25%) complained of moderate anterior pain (average NRS 5.7, range 5–6), while 8 of 16 (50%) patients reported discomfort (average NRS 3.5, range 2–4) around the patella. No statistically significant correlation was found between intraoperative findings on patellar blood flow and the presence of anterior knee pain

Whereas thermography has already been used as an assessment of disease activity in some kinds of inflammatory arthritis, it is a new method for objektive pain evaluation in patients with joint prosthesis. To our knowledge, no study has tested the correlation between increase of temperature and anterior knee pain with total knee prosthesis yet. Thirteen patients were included in this study who suffered from anterior knee pain of the retinaculum patellae with total knee prosthesis. The patients were asked to walk 3 km before entering a room which was cooled down to 20 degrees Celsius. A black 1 cm times 4.5 cm square stripe was attached on the diameter of the patella and the patients rested for 20 minutes to cool down before thermographic fotos were taken from 90 degrees, 45 degrees, frontal medial and lateral. The evaluation of temperature difference of each side was performed by marking a 1cm times 2cm square field rectangular around the black stripe and comparing it with a reference point of the same size 3 cm distal of the field. The patients were compared with thirteen others, not suffering from anterior knee pain. Statistical analysis was performed using a t- test and a p value < 0.05 was considered to be significant. The temperature differences between the rectangular field and the reference point increased significantly on the medial (p= 0.00037) or lateral (p= 0.000002) pain side of the knee. The thirteen knees with knee pain had significantly higher temperature differences between medial and lateral temperature differences, than the knees without knee pain. We demonstrate a significant correlation between anterior knee pain and an increase of superficial skin temperature around the retinaculum patellae. To our knowledge, this is the first report of an objective assessment of pain of the retinaculum patellae with total knee prosthesis

Anterior knee pain in adolescents is generally recognised as a common but benign self-limiting condition. Although many operative procedures for its treatment have been proposed, there is little statistical evidence that they are more effective than expectant management. A group of 54 adolescent girls has been followed for two to eight years from presentation with anterior knee pain. Although some pain persisted in the majority, in many the symptoms declined in severity. This study provides a baseline for comparison with the results of operative intervention; it is suggested that surgical treatment is unproven and unnecessary

Introduction. Anterior knee pain is a common presentation of patello-femoral dysfunction and patients with this disorder represent a significant proportion attending a specialist knee clinic. There is an on-going debate as to the cause and best treatment for such patients. Previous studies on patella-femoral morphology have suggested patella maltracking plays an important part in the aetiology but there had been no studies correlating maltracking with articular cartilage change. Methods. We studied 147 consecutive patients (294 knees) aged between 10 and 63 presenting with anterior knee pain. All underwent MRI tracking scan of their knees as part of the routine investigations. We analysed the prevalence of maltracking with respect to gender, laterality and age groups, as well as patello-femoral articular cartilage changes. Results. 52% of patients were found to have maltracking, of which 75% were bilateral. Furthermore, 66% of patients with maltracking had radiological evidence of patellar articular cartilage changes, corresponding to 61% of 294 knees examined. While majority of these occur at lateral facet, a proportion of medial facet changes (16%) is also seen. More significantly, while 25% of knees from patients with maltracking under the age of 20 are found to have changes on the patella cartilage, this increases to 93% by the age of 50 or above, with step-wise increment per decade of age (p<0.01). Conclusion. Our results demonstrate a strong correlation between anterior knee pain symptoms, patella maltracking and changes in patello-femoral joint cartilages of varying severity. This has implications on the management of these patients and would suggest early correction of maltracking is indicated to prevent deterioration in the patello-femoral joint