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

We performed an advancement and medial transfer of the tibial tuberosity based on Fulkerson's principle to treat intractable anterior knee pain associated with patellofemoral maltracking diagnosed by dynamic MRI. Between January 1998 and July 2000 twenty-two patients had 28 knees operated for anterior knee pain. There were 4 men and 18 women with a mean age of 28 years (range 18-41). Indications for surgery were [a] failure to improve after six months of physiotherapy and [b] patellofemoral maltracking evident in dynamic MRI. Mean follow-up was for 37 months (23 – 42). Knee instability score modified by Fulkerson was employed for objective and subjective assessment. Objectively 22 (79%) knees achieved good to excellent results. Four knees (14%) had fair, and two (7%) had poor results. Excellent and very good results were seen in 20 knees. These patients were a younger age group (mean age 21 years) and had minimal degeneration (grade I-II) of the patellofemoral joints. Two patients achieved good results. One of them had moderate (grade III) and one minimal (II) arthritis. Three knees with fair results had advanced (grade IV or V) and one had moderate (grade III) arthritis. Out of two patients who had a poor result, one had advanced degeneration (grade V) that later required a patellofemoral joint resurfacing. The other was a 24 year old woman with grade II changes. She was treated by the pain therapy team. Anterior displacement of the tuberosity in the presented study was kept to 5 mm to avoid the possible complications of wound break down. The overall length and depth of the osteotomy was also reduced to minimise risk of fracture and commence early mobilisation. Based on our results there is a strong case of justification for Anteromedialisation of tibial tuberosity using a smaller length of osteotomy and lesser degree of anteriorisation in carefully selected patients with Patellofemoral arthralgia associated with maltracking patella

We assessed patellofemoral joint function by combining the measurement of maximal isometric extensor torque at the knee with clinical and radiological measurements in order to calculate the patellofemoral contact force. Eighteen volunteers established the normal ranges of results and the reliability of the system. Of the 39 patients with a variety of knee problems, 29 had anterior knee pain, and all had a subsequent arthroscopy. Patients with anterior knee pain and lesions in the patellar cartilage had significantly reduced isometric contact forces, but those with normal patellofemoral cartilage had normal contact forces. Our method may be useful in providing an objective assessment of anterior knee pain and a quantitative means of monitoring its treatment

Introduction: Poor proprioception and imbalance between quadriceps and hamstrings have been suggested as causes for anterior knee pain. The aim of our study was to compare the proprioception of patients with anterior knee pain to a normal population and to compare the activity of quadriceps and hamstrings using electromyography (EMG) in the 2 groups. Methods: Patients and controls between the ages 11–25 yrs were recruited into the study. The proprioception (stability index) of the patients and controls was tested using the Biodex stability system. This computerised system tests the ability of a person to balance his/her own body on a platform that moves in various directions. Surface EMG was recorded from the quadriceps and hamstrings during this test. EMG was also recorded as the patients and controls stepped onto a 20cm step. EMG activity was normalised to levels elicited during maximal isometric contractions. Results: 18 patients and 27 controls were recruited. We found no significant difference between the groups in the EMG intensity of vastus lateralis relative to biceps femoris, or vastus medialis relative to vastus lateralis, during the balance test or during the step up task (Mann Whitney U test all p> 0.05). We did not find any difference in the proprioceptive abilities of the two groups. Conclusion: We found no significant difference between the groups in the intensity of muscle contraction of the hamstrings relative to the quadriceps, i.e. no evidence for an imbalance in the patients. However the temporal relation between the two needs further investigation

Purpose: The study was designed to evaluate the biomechanical and neurohistological properties of the infrapatellar fat especially concerning its potential role in the anterior knee pain syndrome. Methods: Isokinetic knee extension from 120 of flexion to full extension was simulated on 10 human knee cadaver specimens (6 male, 4 female, average age at death 44 years). Joint kinematics was evaluated by ultrasound sensors (CMS 100TM, Zebris, Isny, Germany), and retro-patellar contact pressure was measured using a thin-film resistive ink pressure system (K-ScanTM 4000, Tekscan, Boston). The infrapatellar tissue pressure was analyzed using a closed sensor cell. The patellar contact pressure was measured before and after resection of the infrapatellar fat pad. The distribution of nerve fibres in the infrapatellar fat pad was assed immunohistologically in a second part of the study. Results: Infrapatellar tissue pressure significantly increased during knee extension < 20 and flexion > 100 ranging from 343 (223) mbar at O- to 60 (64) mbar at 60 of flexion. Total resection of the infrapatellar fat pad resulted in a significant decrease in tibial external rotation of 3° in full knee extension (p=0.011), combined with a significant medial translation of the patella between 29 and 69° knee flexion (p=0.017 to 0.028). Retropatellar contact pressure was significantly (p< 0.05) reduced at all flexion angles, at 120° knee flexion more than in full knee extension. Studying all the detectable nerves present in 50 fields (x200 objective) we found an average of 6.4 substance-P- (25%) of a total of 24.7 nerve fibres in the infrapatellar fat pad. There was a significantly (p< 0.01) higher number of substance-P-fibers (24.4 (28%) of 105.7) in the superficial synovial tissue. The number of S-100-fibers was significantly (p< 0.05) higher in the central and lateral part of the fat pad. Conclusions: Based on these results, we conclude that resection of the infrapatellar fat pad could potentially reduce clinical symptoms in the anterior knee pain syndrome, and that, contrary to commonly believed, the infrapatellar fat pad may have a biomechanical function and play a role in the anterior knee pain syndrome

Postoperative anterior knee pain was evaluated in a consecutive series of 138 knees in 108 patients with rheumatoid arthritis treated by total knee replacement with Mark I Insall-Burstein prostheses. No knee had primary patellar resurfacing, and in the 119 knees followed up for a mean of 63.9 months, none had secondary resurfacing. Anterior knee pain was absent in 87 knees (73%), mild in 16 (13.5%) and moderate or severe in 16 (13.5%). The height of the patella above the prosthetic joint line was the only variable which was directly related to the incidence of anterior knee pain. The sensitivity and specificity of patellar height measurements for identifying patients with or without pain were derived. From these data, a selective policy of resurfacing the patella in those at risk was adopted. Choosing a patellar height of 15 mm or less, patellar resurfacing could be avoided in 80% of patients likely to have no pain, and the patella could be resurfaced in 65% of those likely to have anterior knee pain

Introduction. A comprehensive met-analysis of anterior knee pain post intramedullary nailing of the tibia was performed by Katsoulis et al in 2006. The principle findings were that 47.4% of patients had anterior knee pain at 2 years post tibial nailing. Worse results were found following a patella tendon splitting approach when compared with a medial para-patellar tendon approach. These conclusions were drawn from 20 studies including 1460 patients. Currently both approaches to the proximal tibia for nailing are used at JCMH Blanchardstown. A retrospective study was performed to compare the results of tendon splitting and tendon sparing approaches to tibial nails and to compare the results of JCMH with those stated in literature. Method. Patients who underwent tibial nailing in 2007 and 2008 were identified using the hospital coding system. Those patients who were treated under the care of Mr Kenny had a medial para-tendinous approach and those treated the care of Mr O'Flanagan and Mr Keogh had a tendon splitting approach. Apart from the approach the nailing technique using the Trigen Knee Nail and the post operative physiotherapy protocol were identical. Follow up included questions regarding knee pain and return to previous function. Specifically: Knee pain that affects daily life, Knee pain on kneeling, Knee pain on ascending or descending stairs, Return to work and Return to sports or active hobbies. Results. 61 patients were treated with intra-medullary nailing between 2007 and 2008 43 were available for follow for the purposes of this study (70 %). 25 had nails inserted via a tendon splitting approach and 18 via a tendon sparing approach. Only 5% of patients had knee pain that affected daily life, 16 % had pain on kneeling, 90% of patients who were previously at work returned to work and 75% of patients who were previously engaged in sports were able to return to these activities. Discussion. These results are significantly better than the figures stated in literature in terms of knee pain, return to work and sports. There was no significant difference between the 2 approaches to the tibia again in contradiction of available literature

To assess the prevalence of anterior knee pain more than 5 years after closed intramedullary nailing of the tibia and evaluate the long-term socioeconomic impact of this complication in terms of knee function and employment. A retrospective, cohort study of 298 consecutive tibial intramedullary nailings in 295 patients. Minimum follow-up was 5 years and patients were assessed using a questionnaire and the Lysholm knee score. 26 patients are known to have died, 22 patients, greater than 60 years at the tune of their injury, were excluded, Thus, 251 knees in 248 patients were available for review. The mean age at follow-up was 40. 8 years. The male to female ratio was SA:1 and mean follow-up was 7. 9 years. Anterior knee sensory disturbance was reported by 58% of patients. This interfered with activities of daily living (ADLs) in 29%, work in 25% and sport in 37%. Anterior knee pain was reported by 47% of patients. This interfered with ADLs in 37%, work in 36% and sport in 57%, Anterior knee pain was present all the time in 4%, often in 12%, sometimes in 27%, rarely in 21% and never in 37%, Pain on kneeling was rated on a visual analogue scale as 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 4 1 % knees as excellent, 19% as good, 26% as fair and 14% as poor. 86% of patients have been able to return to work, 9% are currently unemployed and 5% disabled. The presence of anterior knee pain was felt by the patient to prevent return to previous work in 10%. Anterior knee pain persists in 47% of patients after intramedullary nailing of the tibia- There is some decrease in symptoms with time and the majority of patients are able to return to work and activities of daily living. However, anterior knee pain causes significant disability in a small number and all patients should be warned of this problem prior to surgery

PURPOSES. 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

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging. Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique. On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking. Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging. Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique. On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking. Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release

Out of a total of 623 patients who, over a ten-year period, underwent primary total knee replacement (TKR) without patellar resurfacing, 20 underwent secondary resurfacing for chronic anterior knee pain. They were evaluated pre- and postoperatively using the clinical and radiological American Knee Society score. The mean follow-up was 36.1 months (12 to 104). The mean knee score improved from 46.7 to 62.2 points and the mean functional score from 44.7 to 52.2 points. Only 44.4% of the patients, however, reported some improvement; the remainder reported no change or deterioration. The radiographic alignment of the TKR did not influence the outcome of secondary resurfacing of the patella. Complications were noted in six of the 20 patients including fracture and instability of the patella and loss of movement. Anterior knee pain after TKR remains difficult to manage. Secondary resurfacing of the patella is not advocated in all patients since it may increase patient dissatisfaction and hasten revision

Anterior knee pain after total knee arthroplasty (TKA) occurs in 5% to 30% of patients whether or not the patella has been resurfaced. We retrospectively reviewed our patients, none of whom underwent patellar resurfacing. Only 2% had anterior knee pain, none requiring revision surgery. Our follow-up was between two and five years. We paid particular attention to removing osteophytes and conducting a thorough peripatellar synovectomy and a circumpatellar cautery denervation. Our results compare favourably to those in the literature, whether or not the patellae were resurfaced. We conclude that patellar resurfacing in TKA is unnecessary when careful attention is paid to the peripatellar tissues

Introduction and Aims: Many authors believe that patellar resurfacing decreases the incidence of anterior knee pain. We analysed the result of 150 of our own patients. Method: Over the past four years we performed 150 total knee arthroplasties. None of the patellae were resurfaced, osteophytes were carefully removed, the patellae debrided, a thorough peri-patellar synovectomy and circumpatellar cautery denervation performed. All patients were examined by a consultant and a registrar to determine the site of any pain complaint. If there was any controversy a third surgeon was consulted. Results: No patient had pain severe enough to warrant revision surgery. Only two patients had anterior knee pain, and in neither was it marked. Conclusion: We do not know whether our favourable results are attributable to the patellar management, or due to the prosthesis used. We concede that a prospective randomised trial is necessary to determine this, but with such a low incidence of patellar complications we feel this is not ethically justified

The purpose of this study was to evaluate the influence of trochlear design in total knee replacement with and without patellar resurfacing. Methods and Results: In 1992 a trial was set up, including all patients undergoing primary PFC (Johnson & Johnson) total knee replacement. Patients were randomised to either patellar resurfacing or retention. The patients were assessed using the American Knee Society rating, a clinical anterior knee pain score and BOA patient satisfaction score. Assessment was performed without knowing whether the patella had been resurfaced. In July 1998 we began using the PFC Sigma. This incorporates a deeper trochlear groove with a 5° valgus angle. We compared the results for the two types of prosthesis. In the PFC group there were 474 knees in 390 patients. Follow-up was from 2 to 9 years (mean 5.5 years). The overall prevalence of anterior knee pain) was 25.1% (58 knees) and 5.3% (13 knees) in the non-resurfaced group (n=231) versus the resurfaced group (n=243) respectively. Anterior knee pain became apparent in all cases within 18 months. In the PFC sigma group there were 67 knees in 62 patients. Follow-up was from 18 months to 3 years (mean 2 years). The incidence of anterior knee pain was 0 in the resurfaced group (n=30) versus 37.8% (14 knees) in the non-resurfaced group (n=37). Knee scores were lower in the non-resurfaced groups for each prosthesis. Conclusion: The prevalence of anterior knee pain was significantly higher in knees with non-resurfacing of the patella. The asymmetrical, deeper femoral groove improves anterior knee pain with the resurfaced patella but may contribute to it if not resurfaced. We recommend patellar resurfacing in all cases where technically possible

Aims: To report the outcome of secondary patellar resurfacing in patients with chronic anterior knee pain following primary total knee replacement. Methods: A total of twenty patients identified over a 10-year period from 623 patients managed without patellar replacement during primary knee arthroplasty were included and evaluated pre and postoperatively using the American Knee Society (AKS) score, as well as by radiological analysis. Results: The mean follow up was 36.1 months (range 12–104 months). The mean knee score improved from 46.7 to 62.2 points while the mean functional score increased from 44.7 to 52.2 points. Only 44.5% of the patients reported some improvement whereas the remaining reported no change or deterioration. Postoperative radiographic alignment of the primary knee arthroplasty did not influence outcome of secondary patellar resurfacing. Complications were noted in 6 of the 20 patients including patella fracture, patella instability and loss of a range of movement. Conclusions: Anterior knee pain following knee arthroplasty remains a difficult condition to manage and secondary resurfacing of the patella is clearly not to be advocated in all patients since it may well increase patient dissatisfaction and hasten revision

Many authors believe that patellar resurfacing decreases the incidence of anterior knee pain. We analysed the results of 98 of our own patients (103 knees). Over the past two years, we performed total knee arthroplasty on 23 men (one bilateral) and 75 women (four bilateral). None of the patellae were replaced, but we carefully removed osteophytes, debrided the patella, and performed a thorough peripatellar synovectomy and circumpatellar cautery denervation. All patients on our database were telephoned, and those who reported pain were examined independently by a consultant and a registrar. If there was any controversy about the site of the pain, a third surgeon saw the patient. No patient had pain severe enough to warrant revision surgery. Only two (2%) had anterior knee pain, and in neither of them was it marked. We do not know whether our favourable results are attributable to the peripatellar synovectomy and/or circumpatellar cautery denervation. While we concede that a control study of patients who have undergone patellar resurfacing might be necessary before a firm conclusion can be drawn, we question whether, with such a low incidence of patellar problems, this is ethically justifiable

Idiopathic anterior knee pain (AKP) is common in adolescents and young adults. Most believe that the origin of the problem lies in the patello-femoral joint. Hamstring tightness has also been attributed as an important cause. The aim of our study was to compare biometric parameters in patients with idiopathic AKP and controls. We also wanted to assess whether there was a difference in the relative electromyographic (EMG) onset times of the medial and lateral hamstrings. We prospectively recruited patients with idiopathic anterior knee pain in the age group 11 to 25. Patients, but not the control population, had AP, lateral and skyline radiographs taken to rule out other pathology. We had 34 patients (60 knees) with a minimum one year follow up. There was no difference in the symptoms of patients who attended physiotherapy as compared to those who did not. Patients with knee pain had significantly more hip external rotation (63 deg) as compared to the control (47 deg) group (p=0.001). Patients also had significantly more hamstring tightness (p=0.04). Surface EMG was recorded (17 patients and controls each) from the medial and lateral hamstrings during 3 repetitions of a maximal voluntary isometric contraction exercise with the knee at 45° of flexion. The lateral hamstrings contracted 48.7 m.sec earlier than the medial hamstrings in patients as compared to controls. AKP is a multifactorial and self-limiting disorder. Earlier contraction of the lateral hamstrings may cause tibial external rotation and contribute to the symptoms. Our data suggests that physiotherapy did not significantly alter the course of the condition. We believe that increased hip external rotation may contribute to the symptoms by increasing medial facet stress

Anterior knee pain (AKP) is the commonest complication of total knee arthroplasty (TKA). This study aims to assess whether sagittal femoral component position is an independent predictor of AKP after cruciate retaining single radius TKA without primary patellofemoral resurfacing. From a prospective cohort of 297 consecutive TKAs, 73 (25%) patients reported AKP and 89 (30%) reported no pain at 10 years. Patients were assessed pre-operatively and at 1, 5 and 10 years using the short form 12 and Oxford Knee Score (OKS). Variables assessed included demographic data, indication, reoperation, patella resurfacing, and radiographic criteria. Patients with AKP (mean age 67.0 (38–82), 48 (66%) female) had mean Visual Analogue Scale (VAS) Pain scores of 34.3 (range 5–100). VAS scores were 0 in patients with no pain (mean age 66.5 (41–82), 60 (67%) female). Femoral component flexion (FCF), anterior femoral offset ratio, and medial proximal tibial angle all differed significantly between patients with AKP and no pain (p<0.001), p=0.007, p=0.009, respectively). All PROMs were worse in the AKP group at 10 years (p<0.05). OKSs were worse from 1 year (p<0.05). Multivariate analysis confirmed FCF and Insall ratio <0.8 as independent predictors of AKP (R. 2. = 0.263). Extension of ≥0.5° predicted AKP with 87% sensitivity. AKP affects 25% of patients following single radius cruciate retaining TKA, resulting in inferior patient-reported outcome measures at 10 years. Sagittal plane positioning and alignment of the femoral component are important determinants of long-term AKP with femoral component extension being a major risk factor

Introduction. Anterior knee pain (AKP) is a recognized cause of patient's dissatisfaction after total knee arthroplasty. Potential implant/technique related contributors to AKP are patellofemoral maltracking, trochlear geometry, femoral malrotation, patellar tilt and overstuffing. The primary aim of this prospective, matched pair study was to assess the safety, efficacy and performance of an anatomic patella and its effect on AKP in in a matched pair analysis. Material and Methods. Between July 2012 and May 2013, 55 consecutive posterior stabilized cemented Attune TKAs (Depuy) were matched to the PFC Sigma group based on age, gender, and body mass index (BMI). All surgeries were performed via medial parapatellar approach with patellar resurfacing. Clinical and radiographic analysis was performed prospectively with minimum 6 month follow-up. Radiographic measurements included overall limb alignment, anterior offset, posterior offset, joint line, patellar thickness, patellar tilt and patellar displacement by two independent observers. Results. The mean functional outcomes were similar in both groups. AKP incidence between Attune and PFC was statistically insignificant (3.6% and 3.8%). Radiographic analysis revealed no mal-alignment, or osteolysis. No complications such as infection, patellar fracture, subluxation or dislocations were observed. Discussion. Attune knee design demonstrates excellent short-term safety and efficacy. At minimum 6-month follow-up, anatomical patella with shows less AKP than single radius patella design. Longer follow-up is required to assess functional outcome this design

The aim was to compare anterior knee pain (AKP) felt before, and after hamstrings (HS, n = 65) and bone-patellar tendon- bone [B-PT-B, n = 94] ACL reconstructions. The same questionnaire (modified from Shelbourne et al 1997) was answered by patients before, and at least 12 months after surgery. Questions covered five main categories of pain ie. during prolonged sitting, stair climbing, kneeling, sport or vigorous activity, and ADL. There was no statistical difference in the two groups in overall AKP scores before surgery. After surgery, there were improvements in this overall score in both groups, but the improvement was statistically greater in the HS group (p = 0.02). Analysis of the five different pain categories showed no significant difference in the improvements in sitting, sport or ADL. In both climbing stairs (p = 0.009), and kneeling (p = 0.02) there were significantly greater improvements in the HS group. The majority of patients had AKP before surgery. Surgery improved pain levels in both HS and B-PT-B groups, but there was statistically significant greater improvements in overall AKP scores, and the scores for climbing stairs and kneeling in the HS group

We report a rare case of an intracortical chondroma in the region of the medial femoral condyle of the femur extending into the femoral sulcus and the patellofemoral joint.A sixteen year old Asian boy presented with repeated episodes of right sided anterior knee pain and giving way over a three year period. The patient had been treated previously for multiple bony swellings at another hospital and a diagnosis of multiple enchondromatosis had been made. Examination revealed that the patellofemoral compression test was positive with fullness over the medial eminence of the femur in the region of the trochlear groove.Pre-operative X-rays and MRI scan showed the presence of an intracortical lesion over the medial femoral condyle extending into the femoral sulcus. The lesion demonstrated intermediate signal intensity on T1 and high intensity on T2 weighted images with variable low signal intensity foci due to the presence of a calcified matrix. The patient underwent arthroscopic examination. An intra-articular lesion (2cmx 3cm.) was identified and excised through a mini-arthrotomy. The lesion was entirely intra-articular arising from the medial femoral condyle proximal to the femoral sulcus, extending partially into the supra-patellar pouch. Histopathological examination confirmed the presence of a low grade cartilaginous neoplasm best diagnosed as an atypical chondroma. At a two year follow up appointment the patient was found to be asymptomatic with no evidence of radiological recurrence. Although there have been several reports of periosteal chondromas developing around the knee the majority deal with soft tissue chondromas in para-articular locations or intra-cortical tumours in extra-articular regions. Our tumour is unique due to its intra-articular and intracortical location. A detailed review of the literature of this rare tumour is presented with a pictorial presentation of the case including arthroscopic radiological and histopathological findings

Purpose. Anterior knee pain has been relieved by resection of the infrapatellar plica (IPP). The question is: How? The hypothesis is: the IPP acts as an intra-articular ligament, a mechanical link between the forces of knee motion, the fat pad (FP) and the distal femur, holding the FP captive through the arc of motion. Release of the IPP severs this link, allowing the highly innervated FP to move freely. This may allow any underlying pathologic process to heal. Method. Anatomic dissection: In 12 knees, the extensor apparatus was released from the femur and retracted distally allowing relationships to be examined. Cadaver studies: Lateral fluoroscopy was used as well as direct arthroscopic visualization to control implantation of tantalum beads or radiographic contrast material in the FP and IPP. The knee was taken through the arc of motion repeatedly. The femoral attachment of the IPP was then released and knee motion repeated. Traction on the extensor apparatus simulated active motion. In-Vivo Study: The IRB approved study of 12 volunteers undergoing planned knee arthroscopy under local anesthesia. Contrast was placed in the FP and IPP under lateral fluoroscopic control. Passive, then active motion then a quads-set manoeuvre was performed. The IPP was resected and knee motion again recorded. Results. Knees without IPP (4) demonstrated FPs that were lobular, with lateral bodies, and a central process. The fibrous synovial layer of the capsule bypassed the FP inserting on the superior aspect of the menisci. Knees with an IPP (8) showed a FP that was covered by fibrous synovium. The fibrous elements of the capsule coalesced on either side of the patellar in folds that merged with the alar folds. These fibrous elements ramified over and through the FP and were continuous with the upper portion of the IPP medially and laterally. Inferiorly the lower portion of the IPP merged with fibrous synovium that attached to the superior aspect of the menisci and the inter-meniscal ligament. The cadaver studies demonstrated that the IPP elongated with FP distortion as the knee approached full extension and flexion, and that the IPP was lax through mid arc. Release of the IPP at the femur eliminated almost all of the distortion through the full arc. The In-Vivo study replicated the cadaver observations for passive and active motion. The quads set manoeuvre caused further distortion of the FP with the patella moving one cm proximally. Release of the IPP eliminated FP distortion. Conclusion. The IPP seems to act as a true ligamentum mucosum. By virtue of its central femoral attachment if captures the FP against the end of the femur, loosely in mid arc, but with distortion of the FP and stretch of the IPP approaching full flexion and extension. This has been demonstrated in both cadavers and in in-vivo for the first time. Any pathologic process affecting the highly innervated FP will likely be improved by removal of the capture effect of the IPP

Aims: The purpose of the study was to determine the distribution and speciþcation of nerve þbers in the infrapatellar fat pad especially concerning nociceptive substance-P þbres. Methods: The infrapatellar fat pad was taken as a fresh specimen out of 21 patients (4 male, 17 female, mean age 69 years) during total knee arthroplasty. It was dissected in þve deþned parts, þxed and embedded in parafþn. Immunohistochemical techniques using antibodies against S-100 protein and substance-P were employed to determine and specify the nerve þbres. Results: Studying all the detectable nerves present in 50 þelds (x200 objective) we found an average of 6,4 substance-P- (25%) of a total of 24,7 nerve þbres in the infrapatellar fat pad. There was a significantly (p< 0,01) higher number of substance-P-þbers (24,4 (28%) of 105,7) in the surfacing synovial tissue. The number of S-100-þbers was signiþcantly (p< 0,05) higher in the central and lateral part of the fat pad. Conclusions: The occurance and distribution of nerve þbres in the infrapatellar fat pad suggests a nociceptive function. A neurohistological role in the anterior knee pain syndrome is assumed

The incidence of anterior knee pain following total knee replacement (TKR) is reported to be as high as 49%. The source of the pain is poorly understood but the soft tissues around the patella have been implicated. In theory circumferential electrocautery denervates the patella thereby reducing efferent pain signals. However, there is mixed evidence that this practice translates into improved outcomes. We aimed to investigate the clinical effect of intra-operative circumpatellar electrocautery in patients undergoing TKR using the LCS mobile bearing or Kinemax fixed bearing TKR. A total of 200 patients were randomised to receive either circumpatellar electrocautery (diathermy) or not (control). Patients were assessed by visual analogue scale (VAS) for anterior knee pain and Oxford knee score (OKS) pre-operatively and three months, six months and one year post-operatively. Patients and assessors were blinded. There were 91 patients in the diathermy group and 94 in the control. The mean VAS improvement at one year was 3.9 in both groups (control; -10 to 6, diathermy;. -9 to 8, p < 0.001 in both cases, paired, two-tailed t-test). There was no significant difference in VAS between the groups at any other time. The mean OKS improvement was 17.7 points (0 to 34) in the intervention group and 16.6 (0 to 42) points in the control (p = 0.36). There was no significant difference between the two groups in OKS at any other time. We found no relevant effect of patellar electrocautery on either VAS anterior knee pain or OKS for patients undergoing LCS and Kinemax TKR

Tibial and femoral deformities might cause patellofemoral problems, but they do not have to be modified every time to obtain good results. We have evaluated external tibial rotation characterised by an external tibial deformity in varus, worsening in parallel feet position. In these patients the only surgical treatment is tibial osteotomy, justified by a positive effect on the knee joint mechanics. From 1990 to 2002 we performed 25 derotation tibial osteotomies as an isolated procedure or associated with a closed wedge osteotomy. We reviewed 15 patients (16–28 years old at surgery) with special reference to pain, aesthetic criteria and functional assessments, and we reported possible negative effects of derotation (recurvation and external tibial rotation). In all the patients we found an external rotation higher than standard range and moderate varus. All patients had remission of pain; this was complete in five and partial in six. Ten patients showed an increased tibial rotation and eight of those showed even recurvation without functional sequelae. At 2–12 years of follow-up, our results are satisfactory.

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years’ follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years’ follow-up. Cite this article: Bone Joint J 2014;96-B:473–8

Objectives

Our study aimed to examine if a mobile-bearing total knee replacement (TKR) offered an advantage over fixed-bearing designs with respect to rates of secondary resurfacing of the patella in knees in which it was initially left unresurfaced.