Aims. The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process. Methods. This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered unanimous. Results. Of 41 questions and statements on patellar instability, none achieved unanimous consensus, 19 achieved strong consensus, 15 achieved consensus, and seven did not achieve consensus. Conclusion. Most statements reached some degree of consensus, without any achieving unanimous consensus. There was no consensus on the use of anchors in MPFL reconstruction, and the order of fixation of the graft (patella first versus femur first). There was also no consensus on the indications for trochleoplasty or its effect on the viability of the cartilage after elevation of the osteochondral flap. There was also no consensus on postoperative immobilization or weightbearing, or whether paediatric patients should avoid an early return to sport. Cite this article: Bone Joint J 2023;105-B(12):1265–1270

Aims. The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach. Methods. A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered to be unanimous. Results. Of 27 questions and statements on patellar instability, three achieved unanimous consensus, 14 achieved strong consensus, five achieved consensus, and five did not achieve consensus. Conclusion. The statements that reached unanimous consensus were that an assessment of physeal status is critical for paediatric patients with patellar instability. There was also unanimous consensus on early mobilization and resistance training following nonoperative management once there is no apprehension. The statements that did not achieve consensus were on the importance of immobilization of the knee, the use of orthobiologics in nonoperative management, the indications for MPFC repair, and whether a vastus medialis oblique advancement should be performed. Cite this article: Bone Joint J 2023;105-B(12):1259–1264

Introduction. Genu valgum is a common presentation in paediatric patients with congenital limb deformities. The aim of this study is to assess the outcome of guided growth surgery in paediatric patients referred via our physiotherapy pathway with isolated genu valgum and associated patellar instability. Materials & Methods. Patients were identified from our prospective patellar instability database. Inclusion criteria was acquired or congenital genu valgum associated with patellar instability in skeletally immature patients. The mechanical lateral-distal femoral angle was assessed on long leg alignment radiographs (mLDFA <85 degrees). Surgical treatment was the placement of a guided growth plate (PediPlate, OrthoPediatrics, USA) on the medial distal femoral physis (hemi-epiphysiodesis). KOOS-child scores were collected pre-operatively and post-operatively (minimum at 6 months). Results. Eleven patients (seven female) with mean age of 12(range 5–15) were identified. Five patients had congenital talipes equinovarus(CTEV), one fibular hemimelia, one di-George syndrome, one septic growth arrest and three had idiopathic genu valgum. Pre- and post-operative KOOS-child scores showed overall improvement: 58(range 36–68) to 88(65–99) and knee symptoms subscores: 64(43–71) to 96(68–100) p<0.01, t-test. Mean follow-up was 10 months (range 3–23). No subsequent dislocations/subluxations occurred during follow-up. Conclusions. Guided growth surgery is an effective way of treating symptomatic patellar instability in skeletally immature patients with genu valgum in the absence of other structural pathology. It was most common in our cohort in patients with unilateral CTEV. We would recommend to screen syndromic and congenital limb deformity patients for patellar instability symptoms in the presence of genu valgum

Recurrent patellar instability is a common problem and there are multiple demographic and pathoanatomic risk factors that predispose patients to dislocating their patella. The most common of these is trochlear dysplasia. In cases of severe trochlear dysplasia associated with patellar instability, a sulcus deepening trochleoplasty combined with a medial patellofemoral ligament reconstruction (MPFLR) may be indicated. Unaddressed trochlear pathology has been associated with failure and poor post-operative outcomes after stabilization. The purpose of this study is to report the clinical outcome of patients having undergone a trochleoplasty and MPFLR for recurrent lateral patellofemoral instability in the setting of high-grade trochlear dysplasia at a mean of 2 years follow-up. A prospectively collected database was used to identify 46 patients (14 bilateral) who underwent a combined primary MPFLR and trochleoplasty for recurrent patellar instability with high-grade trochlear dysplasia between August 2013 and July 2021. A single surgeon performed a thin flap trochleoplasty using a lateral para-patellar approach with lateral retinaculum lengthening in all 60 cases. A tibial tubercle osteotomy (TTO) was performed concomitantly in seven knees (11.7%) and the MPFLR was performed with a gracilis tendon autograft in 22%, an allograft tendon in 27% and a quadriceps tendon autograft in 57% of cases. Patients were assessed post-operatively at three weeks and three, six, 12 and 24 months. The primary outcome was the Banff Patellar Instability Instrument 2.0 (BPII 2.0) and secondary outcomes were incidence of recurrent instability, complications and reoperations. The mean age was 22.2 years (range, 13 to 45), 76.7% of patients were female, the mean BMI was 25.03 and the prevalence of a positive Beighton score (>4/9) was 40%. The mean follow-up was 24.3 (range, 6 to 67.7) months and only one patient was lost to follow-up before one year post-operatively. The BPII 2.0 improved significantly from a mean of 27.3 pre-operatively to 61.1 at six months (p < 0 .01) and further slight improvement to a mean of 62.1 at 12 months and 65.6 at 24 months post-operatively. Only one patient (1.6%) experienced a single event of subluxation without frank dislocation at nine months. There were three reoperations (5%): one for removal of the TTO screws and prominent chondral nail, one for second-look arthroscopy for persistent J-sign and one for mechanical symptoms associated with overgrowth of a lateral condyle cartilage repair with a bioscaffold. There were no other complications. In this patient cohort, combined MPFLR and trochleoplasty for recurrent patellar instability with severe trochlear dysplasia led to significant improvement of patient reported outcome scores and no recurrence of patellar dislocation at a mean of 2 years. Furthermore, in this series the procedure demonstrated a low rate (5%) of complications and reoperations

Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis. Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis. This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients. Cite this article: Bone Joint J 2017;99-B:159–70

The purpose of this study was to evaluate the reasons for patellar instability in modular rotating hinge TKR, with regards to design of the prosthesis offering unlimited rotation, component positioning and the role of compromised soft tissues. We reviewed six patients with rotating hinge TKR operated over the past 3½ years for either ligamentous instability, bone loss or both. The problem of patellar instability was identified in all patients. Five patients had realignment of extensor mechanism for patellar maltracking, while the remaining one patient with patellar instability was asymptomatic. Post-realignment the HSS scores revealed good results in 3 knees, fair in 2 and poor in 1 patient. All patients had a well aligned knee with satisfactory component positioning. The unlimited rotation offered by the modular rotating hinge TKR because of the absence of a rotational stop causes excessive demands on the soft tissue and is a reason for patellar instability in patients with compromised medial soft tissue integrity. The high incidence of patellar instability compromises the results of TKR and is a cause of concern and this implant should be reserved for patients with severe ligamentous instability and bone loss not amenable to ligament balancing

Hypermobility is an acknowledged risk factor for patellar instability. In this case control study the influence of hypermobility on clinical outcome following medial patellofemoral ligament (MPFL) reconstruction for patellar instability was studied. A total of 25 patients with hypermobility as determined by the Beighton criteria were assessed and compared with a control group of 50 patients who were matched for age, gender, indication for surgery and degree of trochlear dysplasia. The patients with hypermobility had a Beighton Score of ≥ 6; the control patients had a score of < 4. All patients underwent MPFL reconstruction performed using semitendinosus autograft and a standardised arthroscopically controlled technique. The mean age of the patients was 25 years (17 to 49) and the mean follow-up was 15 months (6 to 30). Patients with hypermobility had a significant improvement in function following surgery, with reasonable rates of satisfaction, perceived improvement, willingness to repeat and likelihood of recommendation. Functional improvements were significantly less than in control patients (p < 0.01). Joint hypermobility is not a contraindication to MPFL reconstruction although caution is recommended in managing the expectations of patients with hypermobility before consideration of surgery

Introduction. Current problem – Multiple surgical interventions for patellar instability and no defined criteria for use of medial patellofemoral ligament (MPFL) reconstruction. Aims. Investigate the functional outcomes of MPFL reconstructions that had been performed following selection for treatment based on a defined patellar instability algorithm. Methods. Study design – prospective case series. Treatment number – 19 knees in 17 patients. Intervention – medial patellofemoral ligament reconstruction using free gracillis tendon graft. Inclusion critieria – Recurrent patellar dislocation with a trochlear groove - tibial tubercle (TG-TT) offset of 20mm or less, and trochlear dysplasia and patellar alta classed as normal, mild or moderate. Primary outcome measure – Kujala patellofemoral questionnaire, assessed preoperatively and postoperatively at 6 weeks and 3, 6, 9, 12, 18, 24 months and at final follow up. Secondary outcome measures – Fulkerson patellofemoral scores, return to work, return to preoperative sport and complications. Results. Median follow up time was 24 months (range 12 – 36 months). Kujala scores improved from 58 to 96 (p < 0.05) and Fulkerson scores improved from 56 to 95 (p < 0.05) pre- and postoperatively respectively. The median return to work was 8 weeks and return to preoperative sport was 12 weeks. There was one complication of post-operative stiffness, which settled with intensive physiotherapy. There were no instances of repeat dislocation or patellar fracture. There were no cases needing further surgery. Conclusions. MPFL reconstruction, when performed following selection using our defined treatment algorithm is safe and effective for the treatment of patellar instability. Longer follow up is required to see long term outcomes

Purpose Of The Study: Description of a new operative technique of trochleoplasty for patellar instability and its short-term results. Method: we report a new technique of trochleoplasty for Trochlear dysplasia, using Mitek anchor sutures. The purpose of the procedure is to remove the anterior femoral boss associated with Femoral Trochlear dysplasia and make the floor of the trochlea level with the anterior femoral cortex. The operation entails undermining of the trochlear and lateral condylar articular cartilage to a new corrected level where it is held with the use of No 2 Ethibond Mitek anchor sutures. These anchors are placed in the subchondral bone, suture needle passed through the articular cartilage and the sutures tied over it. Approximately 4 -5 anchor sutures are placed to hold the trochlear cartilage down to the new corrected level. This procedure can be combined with proximal and distal patellar realignment. So far, using this technique, we have operated on six patients with trochlear dysplasia and chronic patellar instability. The patients include 4 females and 2 male with an average age of 33 yrs (range 29 – 40). Average follow up is 16 months (range 8 – 24 months). There has not been any recurrence of patellar instability in the operated patients. Conclusion: Short-term follow up of a new operative technique of troachleoplasty for patellar instability shows promising results

Statement of purpose. To determine whether the Q-angle, measured in a defined and reproducible manner, correlates with the TT-TG distance in patients with patellar instability. Methods and results. The Q-angle represents the angle between the vector of action of the quadriceps and patellar tendon. The normal angle is 14. +/−. 3° in males and 17. +/−. 3° in females. An increased Q-angle is associated with an increased risk of patellar instability, although there is disagreement on its reliability and validity. It can be affected by the anatomical points used to record the measurement, the position of the limb and whether the quadriceps are relaxed or contracted. TT-TG is ascertained by axial CT scanning, with a value exceeding 20mm associated with patellar instability. Q-angles were measured in patients presenting to the patella clinic who had previously undergone Lyon protocol CT scanning for patellar instability. Patients were positioned supine with both feet in neutral rotation taped to a specially designed wooden board (the same position used for CT scanning). The anatomical landmarks were the anterior superior iliac spine, the centre of the patella and the centre of the tibial tuberosity. Both knees were measured with the quadriceps relaxed (relaxed Q-angle) and contracted (contracted Q-angle). Thirty-four knees were measured, 24 pathological and 10 non-pathological. Pearson moment correlation demonstrated a significant correlation between relaxed Q-angle and TT-TG in all knees (R=-0.377; p=0.028). In pathological knees, contracted Q-angle also demonstrated a significant correlation with TT-TG but to a lesser extent than relaxed Q-angle (R=-0.428; p=0.037, R=-0.578; p=0.003 respectively). Linear regression analysis demonstrated relaxed Q-angle as a significant predictor of TT-TG distance in pathological knees. Contracted Q-angle was not significant. Conclusion. The relaxed Q-angle, when measured as above, reliably correlates with and is a significant predictor of TT-TG distance in patients with symptomatic patellar instability

The management of osteoarthritis of the knee associated with patellar instability secondary to external tibial torsion > 45° is challenging. Patellofemoral biomechanics in these patients cannot be achieved by intra-articular correction using standard techniques of total knee replacement. We reviewed seven patients (eight knees) with recurrent patellar dislocation and one with bilateral irreducible lateral dislocation who had undergone simultaneous total knee replacement and internal tibial derotational osteotomy. All had osteoarthritis and severe external tibial torsion. The mean follow-up was for 47.2 months (24 to 120). The mean objective and functional Knee Society scores improved significantly (p = 0.0001) from 29.7 and 41.5 pre-operatively to 71.4 and 73.5 post-operatively, respectively. In all patients the osteotomies healed and patellar stability was restored. Excessive external tibial torsion should be identified and corrected in patients with osteoarthritis and patellar instability. Simultaneous internal rotation osteotomy of the tibia and total knee replacement is a technically demanding but effective treatment for such patients

Aim: To systematically review the present evidence-base, assessing the clinical and radiological outcomes following trochleoplasty for trochlear dysplasia. Methods: An electronic literature search was performed using the AMED, British Nursing Index, CINAHL, Cochrane, EMBASE, ovid Medline, Physiotherapy Evidence Database, PsycINFO, Pubmed and Zetoc databases from their inception to August 2007. Reference lists of identified papers and a hand search of specialist knee journals was also undertaken. All English language, human subject clinical studies, detailing the clinical and/or radiological outcomes of patellar instability patients following a trochleoplasty were included. Two independent reviewers appraised each paper using the CASP tool. Results: Six papers comprising of 117 trochleoplasty procedures on 99 patients were reviewed. Clinically and radiologically, trochleoplasty was shown to be a safe and effective procedure to correct patellar instability in trochlear dysplasia patients. However, the CASP tool identified that the evidence-base reviewed presented with a number of methodological limitations. These included: limited use of inferential statistics; not applying reliable outcome measurements; poor description of patient recruitment; and evaluating small samples. Conclusion: Although trochleoplasty may be an effective procedure to correct patellar instability in trochlear dysplasia patients, further study is recommended to assess longer-term outcomes using well-designed studies

Aims. The purpose of this study was to explore the correlation between femoral torsion and morphology of the distal femoral condyle in patients with trochlear dysplasia and lateral patellar instability. Methods. A total of 90 patients (64 female, 26 male; mean age 22.1 years (SD 7.2)) with lateral patellar dislocation and trochlear dysplasia who were awaiting surgical treatment between January 2015 and June 2019 were retrospectively analyzed. All patients underwent CT scans of the lower limb to assess the femoral torsion and morphology of the distal femur. The femoral torsion at various levels was assessed using the a) femoral anteversion angle (FAA), b) proximal and distal anteversion angle, c) angle of the proximal femoral axis-anatomical epicondylar axis (PFA-AEA), and d) angle of the AEA–posterior condylar line (AEA-PCL). Representative measurements of distal condylar length were taken and parameters using the ratios of the bianterior condyle, biposterior condyle, bicondyle, anterolateral condyle, and anteromedial condyle were calculated and correlated with reference to the AEA, using the Pearson Correlation coefficient. Results. The femoral torsion had a strong correlation with distal condylar morphology. The FAA was significantly correlated with the ratio of the bianterior condyle (r = 0.355; p = 0.009), the AEA-PCL angle (r = 0.340; p = 0.001) and the ratio of the anterolateral condyle and lateral condyle (ALC-LC) (r = 0.309; p = 0.014). The PFA-AEA angle was also significantly correlated with the ratio of the bianterior condyle (r = 0.319; p = 0.008), the AEA-PCL angle (r = 0.231; p = 0.031), and the ratio of ALC-LC (r = 0.261; p = 0.034). In addition, the bianterior condyle ratio showed a significant correlation with the biposterior condyle ratio (r = -0.324; p = 0.027) and the AEA-PCL angle (r = 0.342; p = 0.021). Conclusion. Increased femoral torsion correlated with a prominent anterolateral condyle and a shorter posterolateral condyle compared with the medial condyle. The deformities of the anterior and posterior condyles are combined deformities rather than being isolated and individual deformities in patients with trochlear dysplasia and patella instability. Cite this article: Bone Joint J 2020;102-B(7):868–873

A prospective study was done to assess the outcome of MPFL reconstruction for patellar instability using quadriceps graft. MPFL reconstruction was done using superficial strip of quadriceps by an anteromedial incision and attached close to medial epicondyle of femur. There were 15 knees in thirteen patients with a mean age of 23.4 years. All patients had MPFL reconstruction and 5 had tibial tuberosity transfers. With a mean follow-up of 39.4 (12–57) months, the mean pre-op Kujala scores improved from 47.8 to 87.2. The mean Lysholm scores improved from 54.2 to 86.8. None of the patients had patella re-dislocations. MPFL reconstruction with quadriceps graft appears to be effective producing good results in patients with patellar instability

Background. Patellar instability is a complex, multi-factorial disorder. Radiological assessment is regarded as an important part of the management of this population. The purpose of this study was to determine the intra- and inter-rater reliability of common radiological measurements used to evaluate patellar instability. Methods. One hundred and fifty x-rays from 51 individuals were reviewed by five reviewers: two orthopaedic trainees, a radiological trainee, a consultant radiologist and an orthopaedic physiotherapist. Radiological measurements assessed included patellar shape, sulcus angle, congruence angle, lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), lateral displacement measurement (LDM), boss height, and patellar height ratios (Caton-Deschamps, Blackburne-Peel, Insall-Salvati). All assessors were provided with a summary document outlining the method of assessing each measurement. Bland-Altman analyses were adopted to assess intra- and inter-rater reliability. Results. The results indicated generally low measurement error on intra-rater reliability assessment, particularly for LPD (within-subject variance 0.7mm to 3.7mm), LDM (0.7mm to 3.5mm) and boss height (0.4mm to 1.6mm) for all assessors. There was greater measurement error for the calculation of sulcus angle (0.7° to 10.6°), congruence angle (0.8° to 18.4°) and LPA (0.8° to 16.5°). Whilst the inter-rater reliability between assessors indicated a low mean difference for assessments of patellar height measurements (0.0° to 0.6°), there was greater variability for LPA (0.1° to 3.6°), LPD (0.2mm to 4.6mm) and LDM (0.1mm to 4.0mm), with wide 95% limits of agreement for all measurements indicated poor precision. Conclusions. Many of the standard measurements used to assess the patellofemoral joint on plain radiographs have poor precision. Intra-rater reliability may be related to experience but it seems likely that to achieve good inter-rater reliability, specific training may be required to calibrate observers. More formal training in the technique of radiological measurement for those who were inexperienced might have improved the inter-rater reliability

Recurrent patellar instability is common in young and active patients. Medial patellofemoral ligament (MPFL) reconstruction with a single bundle hamstring graft is one method of surgical treatment for this problem. This is a retrospective case series of patients who underwent MPFL reconstruction by a single specialist knee surgeon between January 2009 and July 2014. Data was collected prospectively for the purpose of service evaluation. Recorded data included gender, age, length of rehabilitation, complications, Knee Injury and Outcome Score (KOOS) and International Knee Documentation Score (IKDC). Data is expressed as mean (range). 108 knees (103 patients) were identified (56 female, 52 male) with a mean age of 24.5 years (12–58). Mean length of rehabilitation was 3.2 months (0–11 months). Three patients required further revision surgery for recurrent instability. KOOS and IKDC scores improved from 44 (4–86) and 38 (2–81), respectively before surgery, to 77 (49–100) and 69 (37–95) after rehabilitation. MPFL reconstruction with a single bundle hamstring graft produces a marked improvement in knee function with a low recurrence of instability

Minor degrees of malalignment of the patella and anatomical abnormalities including a flattened sulcus angle and an increased ratio between patellar tendon length and patellar length (PT:P) have been suggested as predisposing factors in the causation of chondromalacia patellae, as well as patellar instability. In order to confirm or refute this hypothesis a prospective study has been performed comparing the congruence and sulcus angles and the PT:P ratio in a group of 35 patients with chondromalacia confirmed by arthroscopy and a group of 33 patients with instability, with those of a group of 50 knees in normal volunteers. While there was a statistically significant correlation between an increased sulcus and congruence angle and a high-riding patella in patients with instability, no correlation could be identified in patients with idiopathic chondromalacia

Purpose: Patellar instability raises serious clinical and therapeutic problems in children. We present our results with the “soft baguette” technique used since 1974. Material and methods: Sixty-four patients (50 girls and 14 boys) (85 knees) treated between 1974 and 2000 were reviewed. Mean follow-up was 140 months (14–234). For eight knees, section of the lateral wing of the patella was associated. The five types of patellar instability, from permanent dislocation to potential instability, were represented. Results: At last follow-up, 84% of our patients were satisfied with significant improvement in pain, instability and patellar track. We had minor complications in 23.5% of the knees (haematoma, effusions) and eleven recurrences (9.5%) at mid- or long-term which were considered failures. There were no cases of epiphysiodesis. A neoTTA developed in eight cases, proving the efficacy of realignment of the medialised patellar ligament. Following changes in the mechanical axis of these knees revealed a clear trend towards increased valgus. Discussion: The soft baguette technique has fulfilled expectations: stabilisation of the extensor system without injuring the growth cartilage, and trochlear remodelling for the younger patients. The trend towards increased valgus raises a problem. Because of this risk, if the initial valgum is greater than 5° we emphasise the theoretical importance of temporary medial epiphysiodesis associated with the soft baguette to control this potential source of recurrence and therapeutic failure

AIMS. The aim of this study was to assess the knee function after MPFL reconstruction with single hamstring autograft. METHODS-RESULTS. In this case series 68 patients (69 knees) were treated in total. Clinical and radiological evidence of patellar instability and MPFL rupture or deficiency was documented prior to surgery. The MPFL was reconstructed with semitendinosus autograft. The free end of the graft was rerouted through the most distal part of the medial intermuscular septum proximally to the adductor tubercle, to the superomedial border of the patella, where it was fixed, whereas its distal insertion to the tibia was preserved. Knee function was assessed preoperatively and postoperatively with the use of Kujala, Tegner, Lysholm and International Knee Documentation Committee (IKDC) scores. There were 46 male and 22 female patients with an average age of 25.8 years (median age 23) ranging from 11 to 54 years. The mean follow-up was 19.6 months (range 6-54 months). Ten of the patients had findings of femoral trochlear dysplasia. All knee functional scores significantly improved postoperatively. Kujala score improved from 56 to 84, Tegner score improved from 2 to 6, IKDC score improved from 48 to 75 and Lysholm score improved from 53 to 80. One of the patients required revision of the MPFL reconstruction following traumatic redislocation of the patella. CONCLUSIONS. Rerouting of the semitendinosus tendon for the reconstruction of the MPFL is an effective method for the treatment of patellofemoral instability with very good to excellent functional results

The aim of the study was to assess the knee function after MPFL reconstruction with single hamstring autograft. In this case series 86 patients (87 knees) were treated in total, from July 2002 till December 2008. Clinical and radiological evidence of patellar instability and MPFL rupture or deficiency were documented prior to surgery. The MPFL was reconstructed with semitendinosus autograft. The tibial insertion of the graft was retained whereas its free end was rerouted through the most distal part of the medial intermuscular septum, to the supero-medial border of the patella, where it was fixed. Knee function was assessed preoperatively and postoperatively with the use of Kujala, Tegner, Lysholm and International Knee Documentation Committee (IKDC) scores. There were 60 male and 26 female patients with an average age of 29.73 years (median age 28) and range 16–54 years. The mean follow-up was 22.4 months (range 6–78 months). All knee functional scores significantly improved postoperatively. Kujala score improved from 61.3 to 84.8, Tegner score improved from 3 to 5.3, IKDC score improved from 52.4 to 73.8 and Lysholm score improved from 58 to 76.5. The comparison was made between the preoperative and the postoperative values at two years after surgery or at the last follow up, if it was shorter than two years. All scores showed significant improvement after the third postoperative month. One of the patients required revision of the MPFL reconstruction following traumatic redislocation of the patella. Rerouting of the semitendinosus tendon for the reconstruction of the MPFL is an effective method for the treatment of patellofemoral instability. Significant functional improvement is achieved between the third and sixth postoperative months

Background: The medial patellofemoral ligament (MPFL) is the primary stabilizer of the patellofemoral joint. Its reconstruction has been recommended in adults over the past decade after recurrent patellar instability. The purpose of this study was to assess outcomes after MPFL reconstruction in children and adolescent and to prospectively evaluate reconstruction by computed tomography (CT scans) before and after surgery. Materials and Methods: Thirteen consecutive patients (5 boys and 8 girls)(13 knees) underwent a double bundle MPFL reconstruction with hamstring tendon autograft (gracilis:6, semitendinosus: 7) for patellar instability. A bone femoral fixation with interference screw in a tunnel was associated with patellar fixation according to Fithian in mature knees, and a soft tissue procedure was performed in skeletally immature knees. In 5 knees the MPFL reconstruction was isolated while it was associated with medialization and distalization of the tibial tubercle in 8 knees. The mean age at time of surgery was 14.4 years (range, 9.6– 16.5). Patients were evaluated preoperatively and postoperatively by physical, radiological and CT Scans examination and subjectively with the IKDC and Kujala questionnaires. During CT scans with knee fully extended and the quadriceps contracted or relaxed, the patellar tilt angle was assessed. In cases where tibial tubercle was mobilized, the tibial tubercle-trochlear groove (TT-TG) distance was measured pre and postoperatively. Results: No recurrent episodes of dislocation or sub-luxation were reported after 10.5 months (range, 3–23) follow-up after surgery. Mean Kujala score was of 90.2 (range, 84–99) at latest follow-up. For all patients the moving patellar apprehension test was positive before and negative after surgery. A firm end point to lateral patellar translation was noticed in all patients at latest follow-up. Objective assessment with CT noted that the patellar tilt on relaxed quadriceps was significantly improved from 28° preoperatively (range, 16–41) to 16° at follow-up (range, 7–32). The patellar tilt on contracted quadriceps was significantly improved from 35° preoperatively (range, 21–52) to 24.6° at follow-up (range, 11–48). In the specific subgroup, the TT-TG distance decreased preoperatively from 15.4 mm (range, 12–19) to 9 mm postoperatively (range, 2.9–14.8). Conclusion: MPFL reconstruction in children and adolescent is an effective procedure. The patellar tilt was efficiently improved by MPFL reconstruction and these results were correlated with Kujala score. Mid and long term results are still to be evaluated

Purpose of study: To evaluate the clinical outcome of operative intervention for chronic patellar instability for patients treated by a single paediatric orthopaedic surgeon over a 74-month period. Method: There were 11 patients (16 knees) with a mean age at operation of 11.9 years (5 to 17 years). Patients were treated with combined proximal and distal patellar realignment. Mean follow-up was 44.6 months (11–86 months). All patients were assessed post-operatively with satisfaction scores, the Trillat grading system and the Activity Scale for Kids (ASK). They were also questioned specifically for patellofemoral symptoms and examined for signs of mal-tracking. Results: Subjective patient rating of all procedures revealed 10 (62.5%) responses of excellent or very good, 4 (25%) good, 1 (6.25%) fair and 1 poor (6.25%). Formal Trillat grading revealed 9 (56.3%) excellent, 6 (37.5%) good, 1 (6.2%) fair and no poor outcomes. The mean ASK score was 82% (39–100%). All except one patient felt that they would choose to undergo the surgery again. There was one complication of a superficial wound infection. Conclusions: These results show improvement in symptoms and function as judged by Trillat grading and a majority of patients satisfied with the results of the procedure. We feel that the advantage of appropriate surgical intervention at a young age is not only the improvement in symptoms, but also that successful realignment of patellar tracking may reduce subsequent degenerative problems associated with chronic instability and allow better rehabilitation of the dynamic stabilisers of the patellofemoral joint

Lateralisation of the tuberosity tibia causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking patella (LTP), resulting in anterior knee pain, or objective patellar instability (OPI), resulting in recurrent luxations. For a precise preoperative diagnosis the tuberositas tibia (TT) trochlear groove (TG) distance was measured on a CT scan. A distance of more than 15 mm was considered to be pathological. In a prospective study, the clinical results of a subtle, CT-guided medial tuberosity transfer for LTP and OPI were evaluated. 30 Consecutive patients with LTP and 30 patients with OPI and an increased TT TG were included. Outcomes were documented at 3, 12 and 24 months follow-up using the Lysholm scale, the Kujala score, and a visual analogue pain score. Postoperatively all but one patient reported good improvement in stability (no persistent subluxations or luxations). All patients had a marked improvement in pain and functional scores at follow up. Complications seem to be related to the peroperative technique. CT-guided TT transfer appears to be satisfactory and safe method for treating patients with an increased TT TG leading to either LTP or OPI

Medial instability of the patella is most often an iatrogenic condition following surgery for patellofemoral pain or instability. Most often the instability is associated with a previous extensive lateral retinacular release for anterior knee pain without instability.

The symptoms usually involve pain and a sense of medial subluxation at unpredictable times. The clinical diagnosis is based on increased medial laxity of the patella and apprehension with medial translation. A positive gravity subluxation test is often present.

If symptomatic treatment, bracing, and other conservative measures fail, surgery may be helpful. Repair of the vastus lateralis tendon near the proximal patella is usually necessary. The lateral retinaculum should also be reconstituted. At times this can be done with direct repair of the retinacular edges. More frequently the scar tissue filling the defect must be imbricated.

Medial retinacular release has also been reported to be a successful intervention.

A simple procedure of using a Smillie knife to release the lateral patellar retinaculum and the capsule in the unstable patella syndrome is described. The syndrome includes recurrent dislocation, recurrent subluxation and acute dislocation of the patella. Arthroscopy, to exclude any other pathology such as chondromalacia patellae, is performed before proceeding to closed lateral release. The results of this procedure are as good as those after more major surgical procedures. In a small percentage of patients a second operation such as tibial tubercle transfer or patellectomy may be necessary, especially in patients with an underlying congenital abnormality; but in many patients this type of major surgery has proved unnecessary.

Introduction: Patello-femoral instability (PFI) and pain may be caused by anatomical abnormality. Many radiographic measurements have been used to describe the shape and position of the patella and femoral trochlea. Some are difficult to apply when dysplasia is present.

This paper describes a simple new MRI measurement of the axial patellar tendon angle (APTA), and compares this angle in patients with and without patello-femoral instability.

Method: Axial MRI images of the knee of 20 patients with PFI and 20 normal knees (isolated acute ACL rupture) were used for measurement. The angle between the patellar tendon and the posterior femoral condylar line was assessed at three levels from the proximal tendon to its insertion.

Results: In normal knees, the APTA is 11 degrees of lateral tilt at all levels from the proximal tendon to its distal insertion. In PFI knees, the APTA is 32 degrees at the proximal tendon, 27 degrees at the joint line and 22 degrees at the distal insertion. The difference is significant (p< 0.001) at all levels.

Discussion: Measurement of the APTA is reproducible and is easier than many other indices of patello-femoral anatomy. In PFI, the APTA is increased by 21 degrees at the proximal tendon and by 11 degrees at its distal insertion.

In PFI, the patella is commonly tilted laterally. This is matched by the orientation of the patellar tendon. The increased tilt of the tendon is only partially corrected at its distal insertion with an abnormal angle of tibial attachment. When performing distal realignment procedures, angular correction as well as displacement may be appropriate.

Introduction: Patello-femoral instability (PFI) and pain may be caused by anatomical abnormality. Many radiographic measurements have been used to describe the shape and position of the patella and femoral trochlea.

This paper describes a simple new MRI measurement of the axial patellar tendon angle (APTA), and compares this angle in patients with and without patello-femoral instability.

Method: Axial MRI images of the knee of 20 patients with PFI and 20 normal knees (isolated acute ACL rupture) were used for measurement. The angle between the patellar tendon and the posterior femoral condylar line was assessed at three levels from the proximal tendon to its insertion.

Results: In normal knees, the APTA is 11 degrees of lateral tilt at all levels from the proximal tendon to its distal insertion. In PFI knees, the APTA is 33 degrees at the proximal tendon, 28 degrees at the joint line and 22 degrees at the distal insertion. The difference is significant (p< 0.001) at all levels.

Discussion: Measurement of the APTA is reproducible and is easier than many other indices of patello-femoral anatomy. In PFI, the APTA is increased by 21 degrees at the proximal tendon and by 11 degrees at its distal insertion.

In PFI, the patella is commonly tilted laterally. This is matched by the orientation of the patellar tendon. The increased tilt of the tendon is only partially normalized at its distal insertion with an abnormal angle of tibial attachment. When performing distal realignment procedures, angular correction as well as displacement may be appropriate.

Patello-femoral instability (PFI) and pain may be caused by anatomical abnormality. Many radiographic measurements have been used to describe the shape and position of the patella and femoral trochlea.

This paper describes a simple new MRI measurement of the axial patellar tendon angle (APTA), and compares this angle in patients with and without patello-femoral instability.

Method: Axial MRI images of the knee of 20 patients with PFI and 20 normal knees (isolated acute ACL rupture) were used for measurement. The angle between the patellar tendon and the posterior femoral condylar line was assessed at three levels from the proximal tendon to its insertion.

Results: In normal knees, the APTA is 11 degrees of lateral tilt at all levels from the proximal tendon to its distal insertion. In PFI knees, the APTA is 33 degrees at the proximal tendon, 28 degrees at the joint line and 22 degrees at the distal insertion. The difference is significant (p< 0.001) at all levels.

Discussion: Measurement of the APTA is reproducible and is easier than many other indices of patello-femoral anatomy. In PFI, the APTA is increased by 21 degrees at the proximal tendon and by 11 degrees at its distal insertion.

In PFI, the patella is commonly tilted laterally. This is matched by the orientation of the patellar tendon. The increased tilt of the tendon is only partially normalized at its distal insertion with an abnormal angle of tibial attachment. When performing distal realignment procedures, angular correction as well as displacement may be appropriate.

The isolated arthroscopic lateral release has been already presented in the literature as an effective alternative for surgical treatment of different degrees of patellofemoral instability. This paper is to evaluate the long term results of this procedure in patients with recurrent dislocation of the patella (RDP).

Material of this study is a group of patients who underwent isolated arthroscopic lateral release for RDP with a minimum 10 years follow-up. All the patients included presented 1) clear clinical history of RDP 2) positive apprehension test 3) patella able to be dislocated under anesthesia. Were excluded from this study patients who presented 1) generalised ligamentous laxity 2) habitual dislocations of the patella 3) avulsion fracture of the patella 4) marked malalignment 5) age over 40 years. 42 patients met these criteria and 27 (28 knees) were available for follow-up. There were 13 females and 14 males with an average age of 20, 1 years and an average follow-up of 13, 4 years.

All the patients were evaluated for patellar stability and functional outcomes with both Miller and Bartlett and Crosby and Insall scores. According to the evaluation scores above mentioned 16 knees (57%) were rated as excellent /good results.

The isolated lateral release can be considered as the first approach for the treatment of RDP. The outcomes are adversely affected by long term-follow-up, however, it does not compromise any further treatment.

We report on a case of bilateral medial patellar dislocation, studied with hip/knee/ankle TC for evaluation of torsional defects and treated four times with distal derotative femoral osteotomy and cuneiform subtractive osteotomy of the lateral part of the femoral trochlea.

The patient, a woman 18 years of age at the beginning of treatment, presented with femoral neck anteversion of 30° dx and 25° sx referred to the plane passing posteriorly to the distal femoral condyles; the trochlear angle was 140° dx and 144° sx with medial inclination of trochlea due to medial hypoplasia. The patellae were facing medially, and clinically the patient had suffered medial dislocation of the patella several times.

The treatment lasted 4 years: the femoral derotation of 10° was executed by Orthofix monoassial external fixator; the lateral bone wedge removed from the trochlea was about 10 mm and we used reabsorbable nails for fixation.

Current values are 17° of femoral neck anteversion bilaterally, and the trochlear angle is 151° dx and 150° sx. The patient, now 26 years old, has not had any more dislocations and her knees have complete mobility with no pain.

The good result demonstrates the importance of femoral neck anteversion in the genesis of knee disorders. In this case the absence of specific abnormalities of the extensor mechanism (valgus knee, lateralisation of tibial apophyisis) probably caused the hypoplasia of the medial part of the trochlea and the resulting, rare medial patellar dislocation.

We present 10–15 year follow-up of 33 patients who underwent Elmslie-Trillat osteotomy for severe patellar subluxation or dislocation. In the literature it has been reported that tibial tubercle osteotomy predisposes to subsequent patella-femoral arthritis, however it has never been documented if pre existent knee chondral damage has any role in this development. In our group all patients had pre-op knee arthroscopy performed and extant of chondral damage was documented. We pre-formed an evaluation by long-term follow-up to determined weather pre-op chondral damage was the cause of subsequent osteoarthritis of patella-femoral joint.

All patients were invited to attend outpatient clinic for clinical examination and knee radiographs and assessed by an independent research surgeon. Mean age at follow-up was 43 years and average follow-up was 10.5 years (range 10–15 years). 90% follow-up was achieved. Knee function was assessed by clinical scores (Lysholm knee score, American Knee Score, Oxford Knee score, Tegner and Insall knee scores) and three radiographs (AP, Lateral and Merchant views) were performed.

Four patients had developed significant arthritis and underwent joint arthroplasty. Majority of patients reported good results with no further dislocation. However we noticed that extant of pre-op chondral damage was a significant factor in subsequent development of patella-femoral arthritis. We will present our data which is unique as no previous such long-term results have been reported for tibial tubercle transfers followed-up for more than 10 years and have pre-op arthroscopic documented chondral damage.

Background

Recurrent patellar dislocation in combination with cartilage injures are difficult injuries to treat with confounding pathways of treatment. The aim of this study is to compare the clinical and functional outcomes of patients operated for patellofemoral instability with and without cartilage defects.

Abnormal patella height has been found to be one of the main reasons for abnormal contact between patella and trochlear groove leading to patellar instability in children. Many methods have been described to diagnose patellar instability but most of them are justified only in adults. The reason being incomplete ossification in the paediatric population. These methods have been divided into direct and indirect methods. We analysed the MRI scan of knee of 57 children between 12–14 years of age with no previous diagnosis of patellar instability. Patients with a diagnosis of patellar instability, previous surgery on the knee or trauma and poor MRI scan were excluded from the study. We used Insall -Salvati Index (ISI), Caton-Deschamp Index (CDI) and Patella-Trochlear Index (PTI) and compared the results. We found that 40% of measurements by CDI and 41% by ISI showed patella alta in patients with normal patella height. 10% of patients in PTI readings had value suggestive of abnormal patella height. We concluded that PTI is a more reliable index to be used in children as it uses the length of articular surface and does not rely on bony landmarks. Studies done show PTI is a more reliable and accurate method of measuring patella height

Aims. The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective. Methods. The OBC and the patellotrochlear index were used as part of the Oswestry Patellotrochlear Algorithm (OPTA) to guide the surgical treatment of patients with patellar instability. Patients were assigned to one of four treatment groups: medial patellofemoral ligament reconstruction (MPFLr); MPFLr + tibial tubercle distalization (TTD); trochleoplasty; or trochleoplasty + TTD. A prospective analysis of a longitudinal patellofemoral database was performed. Between 2012 and 2018, 202 patients (233 knees) with a mean age of 24.2 years (SD 8.1), with recurrent patellar instability were treated by two fellowship-trained consultant sports/knee surgeons at The Robert Jones and Agnes Hunt Orthopaedic Hospital. Clinical efficacy of each treatment group was assessed by Kujala, International Knee Documentation Committee (IKDC), and EuroQol five-dimension questionnaire (EQ-5D) scores at baseline, and up to 60 months postoperatively. Their safety was assessed by complication rate and requirement for further surgery. The pattern of clinical outcome over time was analyzed using mixed regression modelling. Results. In all, 135 knees (mean age 24.9 years (SD 9.4)) were treated using a MPFLr. Ten knees (7.4%) required additional surgery. A total of 50 knees (mean age 24.4 years (SD 6.3)) were treated using MPFLr + TTD. Ten (20%) required additional surgery. A total of 20 knees (mean age 19.5 years (SD 3.0)) were treated using trochleoplasty + TTD. Three patients (15%) required additional surgery. In each treatment group, there was a significant improvement in Kujala, IKDC, and EQ-5D at one year postoperatively (p < 0.001) with a recognized level of overall complication rate. Conclusion. The OBC is a valid assessment tool to grade patients with trochlear dysplasia and, when used as part of the OPTA, helps to determine treatments that are safe and effective. This fulfils the requirements for its application in mainstream clinical practice. Cite this article: Bone Joint J 2021;103-B(10):1586–1594

Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability. Cite this article: Bone Jt Open 2022;3(3):268–274

Abstract. Introduction. The Syn-VAR RCT is the first of its kind comparing hamstrings autograft v synthetic neoligament for MPFL reconstruction. Our aim is to evaluate short and long term patient related outcomes measures (PROMs) following synthetic / autologous MPFL reconstruction in a heterogenous cohort of patients with recurrent patellar instability. Method. 20 patients meeting inclusion criteria were recruited and randomised. Standardised surgery was performed by a single surgeon in Altnagelvin Hospital with data collected over 3 years from 2016. Kujala score was the primary outcome measure with data captured preoperatively and 12 weeks/2 years postoperatively. Secondary outcomes included four other validated scores and complications including Norwich Patellar Instability, Lysholm, IKDC and Banff. Results. 20 patients with an average age of 19 included 9 females and 11 males. At 12 weeks and 2 years Kujala improvement in the hamstring group was 18 and 32 (both p<0.05) compared to the synthetic group where the increase was 2 and 20 (p<0.05). All secondary score improvements at 2 years were significant (p<0.05) with no difference in any score at all time intervals when comparing both groups (p<0.05). Discussion. Our RCT validates the non-inferiority of synthetic MPFL reconstruction as a treatment for restoring patellar stability in a small heterogenous group with positive long term data and minimal morbidity. With no hamstring harvesting offering a reduction in theatre time with this offers a safe, efficient and viable alternative with reduced morbidity

The February 2023 Children’s orthopaedics Roundup. 360. looks at: Trends in management of paediatric distal radius buckle fractures; Pelvic osteotomy in patients with previous sacral-alar-iliac fixation; Sacral-alar-iliac fixation in patients with previous pelvic osteotomy; Idiopathic toe walking: an update on natural history, diagnosis, and treatment; A prediction model for treatment decisions in distal radial physeal injuries: a multicentre retrospective study; Angular deformities after percutaneous epiphysiodesis for leg length discrepancy; MRI assessment of anterior coverage is predictive of future radiological coverage; Predictive scoring for recurrent patellar instability after a first-time patellar dislocation

The February 2024 Knee Roundup. 360. looks at: Do patients with hypoallergenic total knee arthroplasty implants for metal allergy do worse? An analysis of healthcare utilizations and patient-reported outcome measures; Defining a successful total knee arthroplasty; Incidence, microbiological studies, and factors associated with periprosthetic joint infection after total knee arthroplasty; A modified Delphi consensus statement on patellar instability; Cause for concern? Significant cement coverage in retrieved metaphyseal cones after revision total knee arthroplasty; Prevalence of post-traumatic osteoarthritis after anterior cruciate ligament injury remains high despite advances in surgical techniques; Cost-effectiveness of arthroscopic partial meniscectomy versus physical therapy for traumatic meniscal tears in patients aged under 45 years

Evaluating musculoskeletal conditions of the lower limb and understanding the pathophysiology of complex bone kinematics is challenging. Static images do not take into account the dynamic component of relative bone motion and muscle activation. Fluoroscopy and dynamic MRI have important limitations. Dynamic CT (4D-CT) is an emerging alternative that combines high spatial and temporal resolution, with an increased availability in clinical practice. 4D-CT allows simultaneous visualization of bone morphology and joint kinematics. This unique combination makes it an ideal tool to evaluate functional disorders of the musculoskeletal system. In the lower limb, 4D-CT has been used to diagnose femoroacetabular impingement, patellofemoral, ankle and subtalar joint instability, or reduced range of motion. 4D-CT has also been used to demonstrate the effect of surgery, mainly on patellar instability. 4D-CT will need further research and validation before it can be widely used in clinical practice. We believe, however, it is here to stay, and will become a reference in the diagnosis of lower limb conditions and the evaluation of treatment options. Cite this article: Bone Joint J 2021;103-B(5):822–827

Introduction. The most challenging aspect in rotational deformity correction is translating the pre-operative plan to an accurate intra-operative correction. Landmarks away from the osteotomy site are typically employed at pre-operative planning and this can render inadequate correction. Our proposed technique of pre-operative planning using CT scan and leg length radiographs can translate to accurate intra-operative correction. Materials and Methods. A circle was superimposed at osteotomy site with its centre serving as the centre of correction of rotation. Medio-lateral distance at osteotomy site measured and used as diameter of the circle. Circumference of the circle was calculated by multiplying diameter with Pi and used in the below formula to obtain accurate de-rotation distance;. Derotation distance = (Circumference/360) × correction value for desired ante-version. The exact site of osteotomy was measured in theatre under C-arm and exposed. Derotation distance was marked on the surface of bone as point A and point B with a flexible ruler. Osteotomy performed with saw and derotation was done till point A and point B were co-linear. Derotation distance obtained using this technique is specific for the site of chosen osteotomy and implies a specific degree of correction for every millimeter derotated. Distal femur was the chosen site of osteotomy if there was associated patellar instability and proximal femur if there was no patellar instability. Results. We have used the above technique to successfully correct rotational malalignment of femur and tibia in three patients thus far. The foot progression angle improved in all patients following surgery. One patient had post-operative CT scan of the hips which showed accurate reduction of ante-version. Conclusions. Our new technique of rotational deformity correction is simple and reproducible using commonly available tools as CT scan and leg length radiographs. This technique effectively translates the pre-operative plan to accurate intra-operative correction of rotational deformity

Aims. The Bereiter trochleoplasty has been used in our unit for 12 years to manage recurrent patellar instability in patients with severe trochlea dysplasia. The aim of this study was to document the outcome of a large consecutive cohort of patients who have undergone this operation. Patients and Methods. Between June 2002 and August 2013, 214 consecutive trochleoplasties were carried out in 185 patients. There were 133 women and 52 men with a mean age of 21.3 years (14 to 38). All patients were offered yearly clinical and radiological follow-up. They completed the following patient reported outcome scores (PROMs): International Knee Documentation Committee subjective scale, the Kujala score, the Western Ontario and McMaster Universities Arthritis Index score and the short-form (SF)-12. . Results. Outcomes were available for 199 trochleoplasties in 173 patients giving a 93% follow-up rate at a mean of 4.43 years (1 to 12). There were no infections or deep vein thromboses. In total, 16 patients reported further patella dislocation, giving an 8.3% rate of recurrence. There were 27 re-operations, giving a rate of re-operation of 14%. Overall, 88% were satisfied with the operation and 90% felt that their symptoms had been improved. . Conclusion. All PROMs improved significantly post-operatively except for the mental component score of the SF-12. Trochleoplasty performed using a flexible osteochondral flap is an effective treatment for recurrent patellar instability in patients with severe trochlea dysplasia and gives good results in the medium term. Cite this article: Bone Joint J 2017;99-B:344–50

Abstract. Background. The primary objective of the study is to determine the function outcome and survivorship of patellofemoral replacement. The secondary aim is to find the determinants of successful/poor outcome. Methods. This retrospective study involved 45 patients who underwent AVON patellofemoral replacement between January 2015 to December 2020 with the minimal follow-up off for 12 months. The functional outcome was measured using Oxford Knee score (OKS), EuroQol five dimension (EQ-5D). IWANO and Kellgren-Lawrence classification was used to analyse radiographs. To identify determinants of outcome, the following subgroups the presence or absence of normal alignment, tibiofemoral arthritis, trochlear dysplasia and previous surgery. Complications and revision rates were also recorded. Results. The mean follow-up period was 41.7 +/− 8.3 months with no patients lost in follow-up. Patellofemoral replacement significantly improved the Oxford Knee score (OKS), EuroQol five dimension (EQ-5D) (p<0.001). Four out of 45(8.9%) patients underwent revision surgery. Patients with normal alignment preoperatively did worse than those with abnormal alignment with patellar instability. Patients with grade two tibiofemoral arthritis, history of previous surgery did significantly worse with poorer functional outcome. Conclusion. Patellofemoral arthroplasty is reliable treatment option which improves patient function and quality of life with good survivorship in isolated patellofemoral arthritis in mid-term follow-up

Introduction. Patellofemoral instability is one of the most common presentations to a children's orthopaedic clinic. Recurrent patellar dislocations and instability episodes are painful, disabling and increase the risk of irreversible chondral damage. The medial patellofemoral ligament is the primary static stabiliser to prevent lateral dislocation of the patella and is almost always torn or attenuated in these cases. Reconstruction of this ligament is commonly performed using autologous hamstring tendon however there has been some interest recently in use of quadriceps tendon as a graft. Children with patellar instability also present unique challenges due to the small size of the patella and the presence of open growth plates which may require adaptations to the common techniques. Methods. Patients undergoing medial patellofemoral ligament reconstruction using quadriceps tendon autograft were identified using electronic theatre records. Prospectively collected clinical records and imaging findings were reviewed and underlying pathology, additional procedures at time of MPFL reconstruction, current function and need for further revision surgery determined. Results. Between January 2019 and August 2023, 50 MPFL reconstructions were performed in 37 children using partial thickness quadriceps autograft. Patient age at time of surgery ranged from 5 to 17 years (median age 13 years). The technique was utilised for a variety of indications including recurrent traumatic and habitual patellofemoral instability, fixed dislocations, and revision MPFL reconstruction. Conclusion. Partial thickness quadriceps tendon autograft can be used safely to primarily reconstruct the medial patellofemoral ligament in paediatric population, including those children with open growth plates. It also has utility in revision cases following previous failed hamstring MPFL reconstruction. We have noted that the younger the child, the more distal to the physis lies the femoral point of isometricity, rendering this a safe and reproducible treatment in this age group. Use of this technique has increased in our unit as we have observed that patients seem to be satisfied with their clinical and functional outcomes with a low incidence of short- and medium-term complications

An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients. In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score. Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation. If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella

Objective patellar instability has been correlated with dysplasia of the femoral trochlea. This in vitro study tested the hypothesis that trochleoplasty would increase patellar stability and normalise the kinematics of a knee with a dysplastic trochlea. Six fresh-frozen knees were loaded via the heads of the quadriceps. The patella was displaced 10 mm laterally and the displacing force was measured from 0° to 90° of flexion. Patellar tracking was measured from 0° to 130° of knee flexion using magnetic sensors. These tests were repeated after raising the central anterior trochlea to simulate dysplasia, and repeated again after performing a trochleoplasty on each specimen. The simulated dysplasia significantly reduced stability from that of the normal knee (p < 0.001). Trochleoplasty significantly increased the stability (p < 0.001), so that it did not then differ significantly from the normal knee (p = 0.244). There were small but statistically significant changes in patellar tracking (p< 0.001). This study has provided objective biomechanical data to support the use of trochleoplasty in the treatment of patellar instability associated with femoral trochlear dysplasia

Purpose: The purpose of this work was to analyse functional results in patients with objective patellar instability who underwent surgery between 1988 and 1999. Material and methods: One hundred eighty knees, 140 patients, were included in this series. Minimum follow-up was two years, and the mean follow-up was five years (range 24 – 152 months). The IKDC 99 subjective knee chart was used for postoperative assessment. This chart has ten items for sports activities and functional status of the knee for everyday activities. Eighty-three percent of the patients (118 patients) responded to the questionnaire. Results: Clinical assessment was available for 98 patients (63%) and phone interview data for 29 (20%). Subjectively, 111 (94.87%) patients were very satisfied, five (4.27%) were satisfied, and one was dissatisfied. We assessed results by pain level (37.6% mild or weather-related pain), residual oedema, sensation of blockage (15.8%), instability, daily activities (68% with difficulty in the kneeling position), sports activity and level. Discussion: Certain authors (Insall) question the pertinence of operating objective patellar instability because of the risk of secondary femoropatellar degeneration. For us, surgical treatment is indicated when there has been at least one dislocation associated with morphological anomalies. We have not observed any cases of femoroatellar degeneration among our patients who were operated on more than ten years ago. The patients’ own subjective assessment shows that surgical treatment with medialisation and/or lowering of the tibial tuberosity has been effective with a very excellent rate of satisfaction. The quality of the results is directly related to correct treatment of the lesions (for patients without recurrent dislocation) and systematic analysis of the different factors contributing to patellar instability (trochlear dyplasia, patellar height, quadriceps dyplasia, length of the patellar tendon). Our rate of revision appears to be low but was directly related to the young age of this population and is close to or above the revision rates observed in series with follow-ups greater than two years. Conclusion: Surgery for objective patellar instability gives good mid- and long-term results. The subjective IKDC score allows precise self-evaluation. We have not been able to find any correlation between subjective results and objective results

The August 2015 Children’s orthopaedics Roundup. 360 . looks at: Learning the Pavlik; MRI and patellar instability; Cerebral palsy and hip dysplasia; ‘Pick your poison’: elastic nailing under the spotlight; Club feet and surgery; Donor site morbidity in vascularised fibular grafting; Cartilage biochemistry with hip dysplasia; SUFE and hip decompression: a good option?

Purpose: Even with modern ancillary and good surgical experience, rotational implant positioning is sometimes sub-optimal, leading to poor results. Except for obvious cases with patellar instability, the symptoms are often vague and non-contributive to the diagnosis of failure. This is why implant malpositioning and particularly malrotational postioning remain an underestimated cause of failure after primary total knee arthroplasty (TKA). We report our experience with TKA revision for rotational malpositioning. Method: We retrospectively assessed the results of TKA revisions in 22 knees for malrotational positioning. In all cases, malrotational implant positioning was confirmed by CT-scan according to Berger’s protocol. Results: Mean age was 66 years (47–74) at the time of the primary TKA. After the index procedure, all patients presented early anterior knee pain with patellar instability (tilt and subluxation in ten cases, and permanent patellar dislocation in two cases). Malrotational positioning predominated on the tibial component with mean 23° internal rotation. Mean cumulative malrotation (tibial plus femur) was 22° internal rotation. All but four patients underwent femoral and tibial component revision. In two cases, only the tibial component was revised, and in two other cases, isolated transposition of the anterior tibial tuberosity was carried out. One was a failure, and finally underwent a successful full revision. At a mean follow-up of 30 months (12–60), we noted significant functional outcome improvement. One patient, who underwent a patellectomy previously at the index TKA procedure, had persistant anterior knee pain. No patient presented patellar instability. Conclusion: The diagnosis of implant malrotational positioning is sometimes difficult. The most common errors are tibial component positioning. In case of suspicion of malrotational positioning, protocolized CT-scan allows quick and simple diagnosis. If the malrotation is confirmed, TKA revision should be performed upon patient disability and severity of the symptoms. It is important not to delay the surgery, particularly in cases of patellofemoral dislocation because of the risks of developing soft tissue contractures resulting in a more difficult revision procedure

Background: No studies exist about the long-term correlation of patellofemoral osteoarthrosis to poor outcome after traditional realignment surgery for chronic patellofemoral instability. The objective of this study was to evaluate the recurrent instability and symptomatic osteoarthrosis over a long follow-up period. Methods: Fifty-two patients underwent distal realignment surgery for chronic patellar instability, 28 with Roux-Goldthwait procedure and 24 with Krogius procedure. A follow-up evaluation was performed at a mean 12 years (range, 8 to 22 years) after surgery, in which 39 of 52 patients participated. Recurrent instability and osteoarthrotic characteristics were evaluated by plain radiographs and magnetic resonance images obtained at follow-up. The original hospital data were reviewed to assess patients’ background. Subjective symptoms were assessed with patellofemoral scores. Results: Of the 39 controlled patients, 10 had chronic patellar instability, including 4 patients who underwent reoperation during follow-up. The mean patient age at follow-up was 33 years (range, 26 to 43). Patellofemoral full-thickness cartilage lesions were found on MRI in 29 (75%) of patients and all of the patients had mild lesions. A joint space narrowing was present in 6 cases in plain radiographs indicating severe patellofemoral osteoarthrosis. Only 48% of the patients reported satisfaction with the patellar stability and anterior knee symptoms and the unsatisfactory result was associated with patellofemoral osteoarthrosis (P=0.05). The mean Kujala score was 83 (range 52–100) points. The surgical technique employed did not affect the overall outcome. Conclusion: The long-term outcome of traditional realignment surgery for chronic patellofemoral instability seemed to be strongly associated with patellofemoral osteoarthrosis. Despite the relatively rare occurrence of recurrent instability, less than half of patients achieved a satisfactory result. Patellofemoral osteoarthrosis seems to be the long-term consequence in patients treated with traditional surgical procedures for patellar instability. In future studies focusing on patellar stability, preventive methods against the development of patellofemoral osteoarthrosis should be emphasized

Malreduction of the syndesmosis is a poor prognosticator following ankle fracture and has been documented in as many as 52% of patients following fracture fixation. The current standard for assessment of reduction of the syndesmosis is bilateral computed tomography (CT) scan of the ankle. Multiple radiographic parameters are utilized to define malreduction, however, there has been limited investigation into the accuracy of these measurements to differentiate malreduction from inherent anatomical asymmetry. The purpose of this study was to identify the prevalence of positive malreduction standards within the syndesmosis of native, uninjured ankles. Bilateral lower extremity CT scans including ankles were screened. Studies were excluded if the patient was skeletally immature, had pathology below the knee or if they had congenital neuromuscular syndromes. The resulting cohort consisted of 207 patients. The indication for bilateral CT scan was femoral acetabular impingement in 110 patients (53%), rotation assessment following arthroplasty in 32 patients (15%), rotation assessment following femoral fracture in 30 patients (14%), rotational assessment for patellar instability in 30 patients (14%) and five miscellaneous indications (2%). Fifty patients were reviewed by three observers independently and to determine inter-observer reliability. A single observer repeated the measurements within the same cohort four weeks later to evaluate intra-observer reliability. Three observers then measured the anterior syndesmotic distance, posterior syndesmotic distance, central syndesmotic distance, fibular rotation and sagittal fibular translation at 1cm from the distal tibial articular surface. Overall side to side variability between the left and right ankle were assessed. Previously studied malreduction standards were evaluated. These included: anterior to posterior syndesmotic distance > 2mm, central syndesmotic difference > 1.5mm, average syndesmotic distance > 2mm, fibular rotational difference > 10o and sagittal translational difference > 2mm. The inter- and intra-observer reliability was good to excellent for anterior, posterior and central syndesmotic distance, and fibular rotation measurements. Sagittal fibular translation had an ICC of 0.583, and thus was only of fair reliability. Side to side comparison revealed statistically significant difference in only anterior syndesmotic difference (p=0.038). A difference of anterior to posterior syndesmotic distance of greater than 2mm was observed in 43 patients (20.2%). Thirty eight patients (17.8%) had a central syndesmotic difference of greater than 1.5mm. A fibular rotational difference of greater than 10o was observed in 49 patients (23%). The average difference between the anterior and posterior syndesmosis was greater than 2mm in 17 patients (8.2%). Nine patients (4.2%) had sagittal translation of greater than 2mm. Eighty one patients (39%) demonstrated at least one parameter beyond previously set standards for malreduction. Only one parameters was anomalous in 54 patients (26%), 18 patients (8%) had two positive parameters, while eight patients (4%) had three. One patient was asymmetrical in all measured parameters. In this study there was no statistically significant asymmetry between ankles. However, 39% of native syndesmoses would be classified as malreduced on CT scan using previously studied malreduction limits. Current radiographic parameters are not sufficient to differentiate mild inherent anatomical asymmetry from malreduction of the syndesmosis

Patellofemoral complications are common after total knee replacement (TKR). Leaving the patellar unsurfaced after TKR may lead to complications such as anterior knee pain, and re-operation to surface it. Complications after patellar resurfacing include patellar fracture, aseptic loosening, patellar instability, polyethylene wear, patellar clunk and osteonecrosis. Historically, patellar complications account for one of the larger proportions of causes of failure in TKR, however, with contemporary implant designs, complication rates have decreased. Most remaining failures relate to patellofemoral tracking. Understanding the causes of patellofemoral maltracking is essential to prevent these complications as well as manage them when they occur. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):84–6

Purpose: Patellar instability is a common clinical problem affecting a young, active population. A large number of procedures have been described to treat patellar instability. We present the clinical results in a case series of 25 medial patellofemoral ligament reconstructions in 21 patients with up to 30 months follow-up (mean 7.3 months). Methods: Reconstruction was performed using either the gracilis tendon (6 cases) or semitendinosus tendon (19 cases) autograft. At follow-up the Tegner activity scores, objective knee function, complications and reoperations were assessed. Results: No patella re-dislocations were observed. Five patients (20%) required a manipulation under anaesthetic but subsequently regained a satisfactory range of motion. Two patients (8%) had post operative complications. One patient developed a post operative infection which required a washout and one patient developed a neuroma related to the hamstring harvest site which was excised. Both subsequently returned to work with a full range of motion. No patients sustained a patellar fracture. Conclusions: Medial patellofemoral reconstruction with both gracilis and semitendinosus tendon graft using a longitudinal tunnel technique provided good postoperative patellar stability restoring the primary soft tissue restraint to pathological lateral patellar displacement. Level of evidence: Level IV, therapeutic case series

Patellar instability is a common clinical problem affecting a young, active population. A large number of procedures have been described to treat patellar instability. We present the clinical results in a case series of 25 medial patellofemoral ligament reconstructions in 21 patients with up to 30 months follow-up (mean 7.3 months). Reconstruction was performed using either the gracilis tendon (6 cases) or semitendinosus tendon (19 cases) autograft. At follow-up the Tegner activity scores, objective knee function, complications and reoperations were assessed. No patella re-dislocations were observed. Five patients (20%) required a manipulation under anaesthetic but subsequently regained a satisfactory range of motion. Two patients (8%) had post operative complications. One patient developed a post operative infection which required a washout and one patient developed a neuroma related to the hamstring harvest site which was excised. Both subsequently returned to work with a full range of motion. Medial patellofemoral reconstruction with both gracilis and semitendinosus tendon graft provided good postoperative patellar stability restoring the primary soft tissue restraint to pathological lateral patellar displacement

We present the ten- to 15-year follow-up of 31 patients (34 knees), who underwent an Elmslie-Trillat tibial tubercle osteotomy for chronic, severe patellar instability, unresponsive to non-operative treatment. The mean age of the patients at the time of surgery was 31 years (18 to 46) and they were reviewed post-operatively, at four years (2 to 8) and then at 12 years (10 to 15). All patients had pre-operative knee radiographs and Cox and Insall knee scores. Superolateral portal arthroscopy was performed per-operatively to document chondral damage and after the osteotomy to assess the stability of the patellofemoral joint. A total of 28 knees (82%) had a varying degree of damage to the articular surface. At final follow-up 25 patients (28 knees) were available for review and underwent clinical examination, radiographs of the knee, and Cox and Insall scoring. Six patients who had no arthroscopic chondral abnormality showed no or only early signs of osteoarthritis on final radiographs; while 12 patients with lower grade chondral damage (grade 1 to 2) showed early to moderate signs of osteoarthritis and six out of ten knees with higher grade chondral damage (grade 3 to 4) showed marked evidence of osteoarthritis; four of these had undergone a knee replacement. In the 22 patients (24 knees) with complete follow-up, 19 knees (79.2%) were reported to have a good or excellent outcome at four years, while 15 knees (62.5%) were reported to have the same at long-term follow-up. The functional and radiological results show that the extent of pre-operatively sustained chondral damage is directly related to the subsequent development of patellofemoral osteoarthritis. Cite this article: Bone Joint J 2013;95-B:478–85

Trochlear dysplasia is an important anatomical abnormality in symptomatic patellar instability. Our study assessed the mismatch between the bony and cartilaginous morphology in patients with a dysplastic trochlea compared with a control group. MRI scans of 25 knees in 23 patients with trochlear dysplasia and in 11 patients in a randomly selected control group were reviewed retrospectively in order to assess the morphology of the cartilaginous and bony trochlea. Inter- and intra-observer error was assessed. In the dysplastic group there were 15 women and eight men with a mean age of 20.4 years (14 to 30). The mean bony sulcus angle was 167.9° (141° to 203°), whereas the mean cartilaginous sulcus angle was 186.5° (152° to 214°; p < 0.001). In 74 of 75 axial images (98.7%) the cartilaginous contour was different from the osseous contour on subjective assessment, the cartilage exacerbated the abnormality. Our study shows that the morphology of the cartilaginous trochlea differs markedly from that of the underlying bony trochlea in patients with trochlear dysplasia. MRI is necessary in order to demonstrate the pathology and to facilitate surgical planning

Purpose of the study: Despite a survival rate to the order of 90–95% at ten years, implant malposition and particularly malrotation can cause an underestimation of failure after total knee arthroplasty (TKA). We report our experience with revision TKA for isolated malrotation. Material and methods: Twelve patients underwent revision for isolated maltrotation of an implant. This series of three men and nine women, mean age 66 years, range 47–74 years at primary surgery, were reviewed retrospectively. During the follow-up, all patients complained of early onset anterior knee pain, which was generally noted severe, associated with moderate patellar instability in four cases, noted severe in 7 others and extreme in one (permanent patellar dislocation). Half of the patients also exhibited hyperlaxity was invalidating instability. Range of motion was generally preserved (2/5/100). In all cases, the rotational problems were confirmed on the computed tomography which revealed predominant tibial malrotation, measured at 23 mean internal rotation and a cumulative malrotation (femur+tibia) of 22 internal rotation. Results: All patients except two required revision of both femoral and tibial implants. In one case, the tibial piece was alone changed and in another, isolated translation of the anterior tibial tuberosity was performed. For eight of eleven cases, the revision implants had a stem and femoral inserts were used to control the bone stock loss induced by the corrective cuts in six cases and requiring more or less extensive ligament balance procedures in six. At mean follow-up (30 months, range 12–60), there was a very significant improvement in the functional results; only one patients with a history of patellectomy complained of persistent anterior pain. None of the patients complained of patellar instability. Discussion: Excessive cumulative internal rotation of the implants induces increased stress on the patella, causing early anterior pain, then subluxation and finally dislocation beyond −15 to −20° internal rotation. These position errors are concentrated on the tibia were care must be taken to respect the anatomic landmarks (bicondylar axis, anterior tibial tuberosity) to avoid early failure. In the event of major rotational disorders, revision may be required with procedures to correct the ligament balance

Aims: We studied by means of a magnetic resonance imaging (MRI) protocol, the junction area between supratrochlear (ST) surface and the femoral trochlear groove (FT). The variations of this junction area are they correlated with the patientñs functional signs and with the patellar cartilage injuries?Method: We practised on 87 patients (64 patellar instability, 23 patellar pains) and 25 witnesses, an MRI: DESS and MPR sequences. The trochlear bump was studied in the sagittal plan according to the aspect of the junction area and in measuring itñs height. Results: The junction area was dismembered in 4 types according to its slope with the ST surface: ÒßatÒ, ÒroundÒ, ÒobliqueÒ and ÒsquareÒ. No atÒ typeÒßwas found in cases of FT dysplasia. The ÒobliqueÒ and ÒsquareÒ types were more frequent in cases of important projection of the FT (p< 0.0001). These two types were more frequently associated with the patellar cartilage injuries (p< 0.08). The trochlear projection was maximum (p< 0.0001) in FT dysplasia with spur, with a maximum effect in this case on patellar instability (p< 0.01) and also on patellar pain (p< 0.05). Conclusion: The junction area between the ST surface and the FT groove was dismembered in 4 types. A þrst ßat type without trochlear bump, and 3 types deþning a trochlear Òstep of stairÒ, round, square and oblique in order of growing gravity. The latter two were more common when patellar cartilage injuries existed

Patellofemoral problems are probably the most common type of knee complaint in adolescents and adults. Our aim is to evaluate the mid- and long-term functional outcome, as well as to detect factors affecting it in patients who underwent a modified Elmslie-Trillat procedure. Forty-two patients (49 procedures) were included in this study. Nine were male and the 33 female, with a mean age of 31,3 years (range: 19 to 56). The reason for operation was patellar instability (recurrent subluxation or dislocation) in 13 cases (26,5%), anterior knee pain with malalignment of the extensor mechanism in 17 cases (34,7%) and a combination of both in the remaining 19 cases (38,8%). Patients were followed for a minimum of 18 months and an average of 38,6 months (range: 18 to 130 months). The functional outcome according to Cox’s criteria was excellent in 14 cases (28,6%), good in 20 cases (40,8%), fair in 9 cases (18,4%) and poor in the remaining 6 cases (12,2%). Patients scored an average of 3,57 (range: 2–8) in their Tegner Activity Scale, while their score in Activities of Daily Living Scale of the Knee Outcome Survey ranged from 43 to 98 (average: 75,8). Result analysis revealed that the functional outcome was better in the subgroup that had the procedure due to patellar instability. Furthermore, the outcome was significantly better in the absence of grade 3 or 4 chondral changes in the patellofemoral joint at the time of operation (t-test: p=0,0362). Elmslie-Trillat procedure satisfactorily restores patellofemoral stability and offers a very good functional outcome, especially in the absence of significant chondral changes in the patellofemoral joint at the time of operation

To stabilise the dislocating patella, one can increase the medial vectors, decrease the lateral vectors, or combine these options. Oblique strengthening of vastus medialis increases the medial vectors. This muscle is an active secondary constraint for stabilising the patella. Strengthening this muscle is the cornerstone of treatment of patellar instability, but it is often unsuccessful if the medial patello-femoral ligament is deficient. The medial patellofemoral ligament is the primary passive constraint to lateral dislocation of the patella. Reconstruction of this ligament, which tenses in extension, stabilises the patella in most cases, without the danger of secondary late-stage patellofemoral degeneration. However, in high-riding patellae, effective ligament reconstruction may cause an extensor lag. An elevation of more than 3 mm affects the contact pressures by disturbing the unique relationship between patella and trochlea. Because it can lead to late stage patellofemoral degeneration, trochleaplasty is rarely indicated. Tibial tubercle transfer decreases the lateral vectors and is indicated in cases of severe patella alta, a markedly increased Q-angle and lateral patellar tilt. The tubercle can be transferred distally or medially or internally rotated. The procedure changes the patellofemoral relationship, increasing the load in the medial tibio-femoral compartment and giving rise to the possibility of late-stage degeneration in both the patellofemoral and the tibiofemoral joints. It should not be undertaken lightly and the amount of shift should be conservative. The lateral retinaculum, which becomes lax in extension in right in flexion, provides about 10% of patellar stability to lateral dislocation. Because most patellae dislocate in early flexion, lateral retinacular release is seldom indicated except in the rare cases where the patella dislocates in late flexion. In severe cases of patellar instability, it might be necessary to combine reconstruction of the medial patello-femoral ligament with tibial tubercle transfer and even with lateral retinacular release

Purpose of the study: There remains some debate on the proper treatment of congenital dislocation of the patella in children and adolescents. Ligament-periosteum transfer (green-stick method) is a technique adapted for pediatric patients which realigns the distal extensor system. Material and methods: Between 1979 and 2000, 36 children (51 knees) were treated with this method described by Grammont. Section of the lateral wing and medial capsulomyoplasty were associated in all procedures. Other complementary procedures used as needed included lengthening of the quadriceps, trochleoplasty, and quadriceps release. Mean age at surgery was 11 years (range 5–15 years). All patients were reviewed at bone maturity with a mean follow-up of 7.5 years for functional (IKC criteria) and radiographic assessment. A computed tomography and/or magnetic resonance imaging was obtained preoperatively and at last follow-up to assess TAGT, patellar height, trochlear angle, femoral anteversion, external tibial torsion, and knee rotation. Tibial slope was specifically studied to assess the possible epiphysiodesis effect. Results: Two groups of patients were distinguished: congenital dislocation of the patella (persistent or usual) and objective patellar instability. Functional outcome was good in 74% and 87% of the knees. There were eight cases of recurrent dislocation: five knees were operated on with good outcome. The trochlear angle was improved in both groups, more significantly in the congenital dislocation group. There was one case of an inverted tibial slope (−2°) and two cases of cancelled slope. Discussion: Our functional results are in agreement with earlier reports (Grammont, Bensahel, Langeskiold) but comparison is hindered by the heterogeneous nature of the different cohorts. Radiographically, we observed that trochlear remodeling, a sign of good stability, is better if the operation is performed early (before the age of ten years). On the contrary, in adolescents with major patellar instability, complementary trocheloplasty should be performed in addition to the recentering procedure. We observed that a small tibial slope became smaller in eleven knees in comparison with the nonoperated knee and in comparison with the preoperative slope for the bilateral cases. There appears to be a discrete epiphysiodesis effect but with no functional consequence. Conclusion: We propose a classification of congenital dislocation of the patella in children. The ligament-periosteum transfer technique, associated with other procedures as needed, enables stabilizing the extensor system and a normal trochlear angle if surgery is performed at a young age. Remodeling of the tibial tubercle may result from transient disruption of the vascular supply

Medial patellofemoral ligament (MPFL) reconstruction is used to treat patellar instability and recurrent patellar dislocation. Anatomical studies have found the MPFL to be a double-bundle structure. We carried out a meta-analysis of studies reporting outcomes of patellofemoral reconstruction using hamstring tendon autograft in a double-bundle configuration and patellar fixation via mediolateral patellar tunnels. A literature search was undertaken with no language restriction in various databases from their year of inception to July 2012. The primary outcome examined was the post-operative Kujala score. We identified 320 MPFL reconstructions in nine relevant articles. The combined mean post-operative Kujala score was 92.02 (standard error (. se. ) 1.4, p = 0.001) using a fixed effects model and 89.45 (. se. 37.9, p = 0.02) using random effect modelling. The reported rate of complications with MPFL reconstruction was 12.5% (40 of 320) with stiffness of the knee being the most common. High-quality evidence in assessing double-bundle MPFL reconstruction is lacking. The current literature consists of a mixture of prospective and retrospective case series. High-quality randomised trials evaluating this procedure are still awaited. Cite this article: Bone Joint J 2013;95-B:900–5

Introduction and Aims: Dysplasia of the femoral sulcus is one component that may be present in patients presenting with patellar instability. Rarely the dysplasia is so severe that a dome rather than groove is present. Dejour has reported an operation that deepens the groove, unlike the Albee which elevates it. This study reports the development of a modification of the Dejour trochleoplasty reporting the clinical and radiological results. Method: A consecutive case series of the first 15 patients (17 knees) who underwent a trochleoplasty with a minimum one-year follow-up. There were 11 females and four males with an age range from 15 to 47 years old. Nine patients had had previous operations. The pre-operative length of symptoms ranged from one to 30 years. The patellar instability was managed operatively using the Dejour protocol measuring the patellar height, boss height, tibial tubercle-trochlear groove distance and patellar tilt angle. The Kujala score was used for functional assessment and a subjective assessment was also made. CT scans as well as plain films were used for radiological assessment. The operative technique changed in the light of experience from metallic to absorbable screws as the former abraded the patella. Results: The boss height was reduced from an average of 7.5mm to 1mm (normal 0mm). Tracking became normal in 11 knees and had a slight J-shape in six. Seven knees had a mild residual apprehension. Five patients were very satisfied, eight were satisfied, and two were disappointed. The Kujala score improved from an average of 48 to 73 out of 100. Three patients returned to full sports. Eight patients required further operations apart from the removal of metallic screws in 10 knees. Five of these were arthrolysis for stiffness at about six weeks post-operatively. As a result, patients were placed on a continuous passive motion machine for three to four days to avoid this. One patient went on to have autologous chondrocyte implantation for a defect on the lateral femoral condyle involving the tibial surface. This was after a new injury following a return to sports and not in the area affected by the trochleoplasty. Conclusion: Trochleoplasty for severe dysplasia of the femoral sulcus is a developing procedure. It requires careful attention to detail. For a rare condition the results have been gratifying with an acceptable level of complications. It is not recommended that this procedure be performed by general orthopaedic surgeons

Introduction: Trochlear dysplasia is an important anatomical factor in symptomatic patellar instability. The impression at surgery is that the dysplasia is predominantly an abnormality of the proximal trochlea. There is a mismatch between the bony and cartilaginous trochlear anatomy in normal knees. This study assessed the mismatch in dysplastic trochleas. Methods: The MRI scans of 25 knees in 23 patients with patellar instability and trochlear dysplasia were reviewed retrospectively. Axial fat saturation images where used to assess cartilaginous and bony trochlear morphology. The following parameters were measured in the three most proximal images of each trochlea:. Cartilaginous and bony sulcus angles. Cartilage thickness in the sulcus and on both condyles. Morphology of the bony and cartilaginous surface contour (flat, convex or concave). Horizontal distance of the bony and cartilaginous sulcus measured from the lateral epicondyle. Inter and intra observer error was recorded. Results: There were 15 females and 8 males with an average age of 20.4 years (14 30). The average bony sulcus angle (SA) was 166.9 degrees (141 – 203) whereas the average cartilaginous SA was 184.8 degrees (152 – 222). In 74 of 75 axial images (98.6%) the cartilaginous SA was greater than the bony SA by an average of 17.6 degrees (3 45). The average cartilage thickness in the centre of the trochlea was 3.5 mm (1.4 – 5.2), and the thickness on the lateral and medial condyles were 2.2mm (1.8 3.5) and 1.9mm (0.6 3.3) respectively. In 74 of 75 axial images (98.6%) the cartilaginous contour was different to the osseous contour on subjective assessment. In 58 of 75 images (77.3%) the cartilaginous contour changed the bony morphology from concave to flat or convex, or from flat to convex. In 17 (22.6%) it reduced the concavity. The average horizontal distance of the bony sulcus from the lateral epicondyle was 33.7mm (24 42) and that of the cartilaginous sulcus 31.8mm (23 39). Conclusion: This study demonstrates that the cartilaginous trochlear morphology differs markedly from that of the underlying bony trochlea in patients with trochlear dysplasia. Although the bony trochlea was dysplastic, the cartilage morphology worsened this abnormal shape. Since cartilage is poorly represented on routine radiography and computed tomography, MRI is necessary to demonstrate both the bony and cartilaginous morphology to facilitate surgical planning

In recent years, the use of computed tomography (CT) has made it possible to obtain without distortion images of axial sections of the patella with the knee in the first 15°–20° of flexion. We performed CT examinations on 27 patients aged between 11 and 17 years. We considered patients who had anterior knee pain with or without a feeling of patellar instability. CT examinations were performed with the knee flexed to 15° with and without quadriceps contraction. The tomograms obtained were analysed considering: (1) the congruence angle (CA), (2) the patellar tilt angle (PTA), (3) the sulcus angle (SA) and (4) trochlear depth (TD). We performed CT examinations on a control group of 20 patients aged between 11 to 17 years. Statistical analysis was performed by using the analysis of variation (ANOVA) test or the Student’s t-test on paired or unpaired data. The difference between control knees and symptomatic knees was significant for all of the CT variables (unpaired t-test). Malalignment detected with the quadriceps relaxed was typed according to the classification of Schutzer et al. as follows: type I – lateralised patella, 13 knees (24.1%); type II – lateralised and tilted patella, 24 knees (44.4%); and type III – tilted patella, 12 knees (22.2%). In 26 knees (48.2%), CT examination with quadriceps in contraction gave the same findings as CT examination with the quadriceps relaxed, i.e. type and severity of malalignment were identical. In the remaining 28 knees (51.8%), CT examination with the quadriceps in contraction gave different results from the CT examination with the quadriceps relaxed. The greater sensitivity and specificity of CT as compared with conventional radiographic methods in the diagnosis of patellofemoral malalignment have been demonstrated. Our results show that there is a relationship between clinical findings and CT data. CT assessment with the quadriceps relaxed permitted us to divide the knees into three types of patellofemoral malalignment. To our knowledge, not many studies have been performed with the quadriceps contracted. In the present study, in 48.2% of knees there were no differences between CT assessment with the quadriceps relaxed and with the quadriceps contracted in either type or severity of malalignment. In contrast, in the remaining 51.8% of symptomatic knees we found differences. Before planning an operation in patients with anterior knee pain with or without patellar instability, CT assessment both with the quadriceps relaxed and contracted permits a reliable documentation of malalignment, permitting the surgeon to select the optimal treatment

The June 2024 Children’s orthopaedics Roundup³⁶⁰ looks at: Proximal femoral unicameral bone cysts: is ESIN the answer?; Hybrid-mesh casts in the conservative management of paediatric supracondylar humeral fractures: a randomized controlled trial; Rate and risk factors for contralateral slippage in adolescents treated for slipped capital femoral epiphysis; CRP predicts the need to escalate care after initial debridement for musculoskeletal infection; Genu valgum in paediatric patients presenting with patellofemoral instability; Nusinersen therapy changed the natural course of spinal muscular atrophy type 1: what about spine and hip?; The necessity of ulnar nerve exploration and translocation in open reduction of medial humeral epicondyle fractures in children.

Aims

Tibial tubercle osteotomy (TTO) facilitates surgical exposure and protects the extensor mechanism during revision total knee arthroplasty (rTKA). The purpose of this study was to determine the rates of bony union, complications, and reoperations following TTO during rTKA, to assess the functional outcomes of rTKA with TTO at two years’ minimum follow-up, and to identify the risk factors of failure.

Introduction. Epidemiologic studies indicate that isolated patellofemoral (PF) arthritis affects nearly 10% of the population over 40 years of age, with a predilection for females. A small percentage of patients with PF arthritis may require surgical intervention. Surgical options include non-arthroplasty procedures (arthroscopic debridement, tibial tubercle unloading procedures, cartilage restoration, and patellectomy), and patellofemoral or total knee arthroplasty (PFA or TKA). Historically, non-arthroplasty surgical treatment has provided inconsistent results, with short-term success rates of 60–70%, especially in patients with advanced arthritis. Although TKA provides reproducible results in patients with isolated PF arthritis, it may be undesirable for those interested in a more conservative, kinematic-preserving approach, particularly in younger patients, who may account for nearly 50% of patients undergoing surgery for PF arthritis. Due to these limitations, patellofemoral arthroplasty (PFA) has become utilised more frequently over the past two decades. Indications for PFA. The ideal candidate for PFA has isolated, non-inflammatory PF arthritis resulting in “anterior” pain and functional limitations. Pain should be retro- and/or peri-patellar and exacerbated by descending stairs/hills, sitting with the knee flexed, kneeling and standing from a seated position. There should be less pain when walking on level ground. Symptoms should be reproducible during physical examination with squatting and patellar inhibition testing. An abnormal Q-angle or J-sign indicate significant maltracking and/or dysplasia, particularly with a previous history of patellar dislocations. The presence of these findings may necessitate concomitant realignment surgery with PFA. Often, patients with PF arthritis will have significant quadriceps weakness, which should be treated with preoperative physical therapy to prevent prolonged postoperative pain and functional limitations. Tibiofemoral joint pain suggests additional pathology, which may not be amenable to PFA alone. Conclusion. PFA is effective for the treatment of arthritis localised to the PF compartment. Outcomes can be optimised with proper patient selection, meticulous surgical technique, and selection of an onlay-style implant that can be positioned perpendicular to the AP axis of the femur. Minimizing the risk of patellar instability by using onlay-design PFAs has enhanced mid- and long-term results, and leaves progressive tibiofemoral arthritis as the primary failure mechanism beyond 10–15 years

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

Clinical management of patellofemoral (PF) instability is a challenge, particularly considering the wide range of contributing variables that must be taken into consideration when determining optimal treatment. An important outcome measure to consider in this patient population is disease-specific quality of life (QOL). The purpose of this study was to factor analyse and reduce the total number of items in the Banff Patellar Instability Instrument (BPII). Subsequent to the factor analysis, the new, item-reduced BPII 2.0 was tested for validity, reliability and responsiveness. Disease-specific QOL was measured in patients with a confirmed diagnosis of PF instability (n = 223) at the initial consultation with the original BPII. Data from these BPII scores was used to employ a principal component analysis (PCA) to factor analyse and reduce the total number of items in the original BPII, to create the new BPII 2.0. The BPII 2.0 underwent content validation (Cronbach's Alpha, patient interviews and reading-level); construct validation (ANOVA comparing the initial consultation, 6, 12 and 24 month post-operative, Eta squared); convergent validation (Pearson r correlation to the original BPII); responsiveness testing (Eta squared, anchor-based distribution testing); and reliability testing (intra-class correlation coefficient (ICC) 2,k). The original BPII was successfully reduced from 32 to 23 items. The new BPII 2.0 demonstrated excellent Cronbach's Alpha values: initial consult = 0.91; 6-months = 0.96; 12-months = 0.97; and 24-months post-operative = 0.76. Grade-level reading assessment for all items in the BPII 2.0 was below grade twelve. The ANOVA determined the BPII 2.0 was able to discriminate between the initial consultation, 6, 12 and 24 months post-operative assessments, with significant differences between each time-point (p < 0.05). Eta squared was 0.40, demonstrating a medium to large effect size. Convergent validity was established with the BPII 2.0 significantly correlated to the original BPII (initial consult = 0.82, 6-month = 0.90, 12-month = 0.90, and 24-month = 0.94). Anchor-based responsiveness was established with a significant correlation between the 7-point scale of patient-perceived improvement and 24-month post-operative BPII 2.0 scores. Strong reliability was established with an ICC (2,k) = .97. The BPII has undergone a critical step in its psychometric and clinimetric evolution: structural validation. With the work completed in this study, the BPII and BPII 2.0 have completed assessment of seven of the nine Consensus-based Standards for the selection of health Measurement INstruments (COSMIN) properties including: 1) Internal consistency; 2) Reliability; 3) Standard error of measurement; 4) Content validation; 5) Structural validity; 6) Criterion validity; and, 7) Responsiveness testing. Completion of these assessments and the introduction of a structurally valid and shorter questionnaire, the BPII 2.0, provides a definitive level of credibility to this disease-specific outcome measure

Aims

This study aims to identify the top unanswered research priorities in the field of knee surgery using consensus-based methodology.

Objective. The aim of this study was to evaluate the shape of patella relative to the femoral epicondylar axis and to find sex differences. Materials and methods. Computed tomography (CT) images of 100 knees with tibiofemoral osteoarthritis in 100 patients were prospectively collected. All patients were diagnosed as varus-type osteoarthritis with no destructive patellar deformity. Fifty patients were male and 50 female. The average male age was 70.8±14.6 (mean ± SD) years and the average female age was 73.3±6.7 years. Forty nine knees were right and 51 knees were left. The average height of males was 162.6±7.4 cm and that of females 149.6±5.7 cm. Males were significantly taller than females. The CT scan was performed with 2mm-interval slices in the vertical plane to the long axis of femoral shaft. Every CT image was examined to determine the maximum distance between the medial and lateral femoral epicondyle (inter-epicondylar distance, IED) along the epicondylar axis. The maximum patellar width and thickness were also measured at the image which had these maximum distances, while patellar cartilage thickness in anteroposterior diameter was not measured in this study. For evaluating the patellar size, each measured value was divided by IED and calculated each ratio. The ratio of patellar width to patellar thickness was also calculated. All parameters were compared between males and females. Statistical software Statview ver.5.0 (SAS Institute Inc.) was used for all analyses with significance being set at the 5% level. Results. Measured values are presented on Table 1. The average IED, patellar width and patellar thickness of males were all significantly larger than those of females. As shown in Table 2, by contrast, each ratio to IED was almost the same between the sexes and there were no significant differences. The ratio of patellar width to patellar thickness was 46.7±2.6% in males and 46.6±2.9% in females. Discussion. Although some studies have assessed the actual measurement values of patella, no prior study, to our knowledge, has morphologically evaluated the patella relative to the femur. This is the first study to investigate the configuration and location of patella relative to femoral epicondylar axis. Our results showed the configuration of patella relative to the femoral epicondylar axis was the same between sexes. The patellar width is approximately 56% and TGD is approximately 39% of IED. The most common complications after the surgery are related to patellofemoral problems. The ideal thickness of the resurfaced patella has not been clearly investigated. Patellar disabilities are associated with both decreased and increased patellar thickness— a thin patella could lead to anteroposterior patellar instability and a thick patella could increase the risk of stiffness of the knee and patellar subluxation. Therefore, it is desirable to restore the original patellar thickness during surgery. The results of current study showed that the ratio of patellar width to the patellar thickness was about 47%, which is useful to determine the thickness of patella during surgeries for severely damaged knees or revision surgeries

The aim of this study was to evaluate the functional and clinical outcome following medial patello-femoral ligament reconstruction using autogenous hamstring tendon grafts for patellar instability. Over a 4 year period the senior author operated on 35 patients for lateral instability of the patella. The predominant initiating event was a sporting injury. Each patient had either failed conservative management including physiotherapy, or failed surgical management including tibial tuberosity transfer. Post-operatively, all patients were allowed full flexion and extension. Sporting activity was restricted until 4-6 months post-operatively. Patients were evaluated clinically and functionally. The Fulkerson score was utilised pre- and post-operatively. The minimum follow-up was 6 months, the mean follow-up was 20 months. There were 18 males and 17 females. The mean age was 24.6 years. The mean pre-operative Fulkerson score was 59.3 (range 6-100). The mean post-operative Fulkerson score was 83.6 (range 25-100), the mean improvement was 24.3. 24 patients returned to sporting activities. The main complications were one patient with a patella fracture that was stabilised with internal fixation, one patient requiring exploration and reinforcing the ligament which had attenuated. Both patients finally had a good clinical outcome. Our study has shown that symptomatic lateral instability of the patella can be effectively treated with a medial patello-femoral ligament reconstruction and result in overall good clinical and functional outcome. We would recommend this technique

We examined an39 patients (45 knees) who had undergone Elmslie-Trillat procedure for recurrent or habitual dislocation of the patella with a follow-up of more than ten years. The mean age at the time of surgery was 18.4 years; the mean follow-up was 161 months (120 to 238). Using Fulkerson’s functional knee score, 41 knees (91%) had an excellent or good result at a mean follow-up of 45 months, and this was maintained in 29 (64%) at the final review. The main cause of deterioration in the clinical results was the onset or worsening of patellofemoral joint pain, not patellar instability

Introduction. As intra-operative fluoroscopic identification of the isometric MPFL attachment to the femur can be imprecise and laborious in a surgical setting, we used clinical criteria to identify the isometric point and then studied post-operative radiographs to find out whether it was achieved and compared it with functional outcome. Materials and Methods. Sixteen patients underwent 17 MPFL reconstructions using autologous semi-tendinosis tendon graft. Clinical judgement was used to identify the optimal point for femoral attachment of the MPFL without fluoroscopy control. Post-operative radiographs at 2 weeks were analysed to confirm whether an isometric point for the reconstructed MPFL was achieved by dividing the distal femur into 4 quadrants by 2 lines on the lateral radiograph. Telephonic interview was conducted to assess functional scores using the Kujala score at a mean follow-up of 13 months. Results. In only 4 of the 17 cases, the femoral point of attachment lay in the radiographically isometric (antero-proximal) quadrant. In 8 of 17 knees, the point of MPFL attachment lay in the antero-distal quadrant. However, there was an improvement in the functional score in 14 of 16 patients, with none reporting recurrence of patellar instability. The position of the reconstructed MPFL did not correlate with functional score. Conclusion. Over-reliance on a clinical method alone for identification of the optimal point for MPFL attachment without an intra-operative radiograph leads to radiographically non-isometric positioning in a majority of cases. In the clinical setting, however, this does not correlate with adverse functional outcome, although intra-operative fluoroscopy may improve the anatomical isometry, and we therefore suggest the use of a qualitative clinical method to achieve optimal

We treated 13 patients who had a fixed valgus deformity of the knee with a semiconstrained total knee arthroplasty combined with advancement of the lateral collateral ligament by means of a lateral femoral condylar sliding osteotomy. At follow-up of between one and 6.5 years all patients were assessed using the Knee Society score. The mean knee score improved from 32 to 88 and the functional score from 45 to 73. The mean tibiofemoral angle was corrected from 191° to 180°. There was no postoperative tibiofemoral or patellar instability and, in most knees, distal transposition of the lateral femoral condyle achieved satisfactory stable alignment

Since 1987, autologous chondrocyte implantation (ACI) has been performed in Gothenburg, Sweden in more than 1600 patients. Out of the first 442 patients operated with ACI, 153 (35%) had patella lesions and 91 (21%) had trochlea lesions. Forty two patients (9.5%) had kissing lesions of the patellofemoral joint. The aim of the study was to evaluate the current clinical status of operated patients. Lysholm and Tegner-Wallgren self-assessment questionnaires were used. The patients were requested to compare their current status to previous states and to report whether they would do the operation again. Concomitant realignment procedures of the patellofemoral joint were also recorded and preoperative scores were also assessed from the medical files. Patients were divided into groups according to the location of lesion. All the groups showed a significant improvement compared with the preoperative assessment. Over 90% of the treated patients were satisfied with the ACI and would have undergone the procedure again. It seems that correcting the coexisting background factors with realignment, stabilizing or unloading procedures is improving the results over time. Despite the initial controversy about the results and indication for ACI in patellofemoral lesions, it is clear that ACI provides a satisfactory result even for the difficult cases with concomitant patellar instability. Our study reveals preservation of the good results and of high level of patients’ activities, even 10 to 20 years after the implantation

Purpose. Total knee arthroplasty (TKA) is the preferred treatment for those with end stage osteoarthritis (OA) and severe functional limitations. With the demographic transition in society, TKA is being offered to a younger patient population. Younger patients are generally more active requiring an increased range of motion, and place greater physiological demands on the prosthesis than typical older patients. The mobile bearing (MB) total knee prosthesis has theoretically been designed to meet these demands. We conducted a meta-analysis and systematic review of randomized controlled trials comparing outcomes of MB and fixed bearing (FB) TKA. Method. After testing for publication bias and heterogeneity, the data were aggregated by fixed effects modelling. Our searches identified 14 studies for reporting our primary outcome of Knee Society Scores (KSS). We also pooled data for post-operative range of motion (ROM) and Hospital for Special Surgery scores (HSS). Results. The standard difference in mean outcome scores for KSS and HSS demonstrated no difference between groups (p = 0.902, and p = 0.426 respectively). Similarly, the pooled data for ROM showed no difference between groups (p = 0.265). Conclusion. The results of our systematic review and meta-analysis of the literature indicate that there are no significant differences between MB and FB TKA in the outcome measures of KSS, ROM or HSS at final follow up. Only 3 of 12 studies found any benefit of MB knees in terms of patient reported pain. There were no differences found between FB and MB regarding patellar instability or stair climbing ability. Implant longevity remains the only outcome measure in which MB implants may provide an advantage

Purpose. To assess the midterm functional results after Medial Patellofemoral Ligament (MPFL) reconstruction with single semitendinosis autograft in patients with patellofemoral instability. Methods - Results. Forty six knees (45 patients) with patellofemoral instability were treated with surgical stabilisation of the patella with a single semitendinosis autograft and followed up for a minimum of 24 months. The average follow-up was 33.5 months (range 24-54 months). Clinical evidence of patellar instability and radiological (MRI) evidence of MPFL rupture or deficiency was documented prior to surgery. The average post injury interval was 22.3 months. Ipsilateral joint co-morbidities included previous lateral release or distal realignment (n=10), patellofemoral joint (PFJ) dysplasia (n=14) and concurrent ACL, PCL and/or MCL rupture (n=6). Knee function was assessed preoperatively and postoperatively with the use of Kujala, Tegner, Lysholm and International Knee Documentation Committee (IKDC) scores. There were 34 male and 11 female patients with a mean age of 32.5 years (range 17 - 60 years). All measured knee function scores improved postoperatively. Kujala score improved from 58 to 77 (95%CI +/− 9.71). Tegner score improved from 3 to 5 (95%CI+/− 0.65). IKDC score improved from 51 to 75 (95%CI +/− 5.27) and Lysholm score improved from 59 to 79 (95%CI +/− 6.5). Conclusions. MPFL reconstruction with semitendinosis autograft is an effective treatment at a minimum of 24 months (midterm) follow-up in patients with patellofemoral instability even in the presence of heterogeneous knee co-morbidities such as PFJ dysplasia, previous lateral release and failed realignment surgery

Introduction. There are numerous surgical techniques for medial patellofemoral ligament (MPFL) reconstruction. Problems with certain techniques include patellar fracture and re-rupture. Aim. To investigate the functional outcomes of MPFL reconstructions performed using a free gracillis tendon graft, oblique medial patella tunnel and interference screw femoral fixation. Patients were selected for MPFL reconstruction if they had recurrent patellar dislocations, and with the use of clinical and radiographic evaluation. Methods. A prospective case series of 31 consecutive knees in 28 patients underwent reconstruction of the MPFL using a free gracillis tendon graft, oblique medial patella tunnel and interference screw femoral fixation. Our primary outcome measure was the Kujala patellofemoral questionnaire. This was assessed preoperatively and postoperatively at 6 weeks and 3, 6, 9, 12, 18, 24 months and at final follow up. Secondary outcome measures included Fulkerson patellofemoral scores at the same time intervals, return to work, return to preoperative sport and complications. Results. The median follow up time was 25 months (range 12 – 44 months). Kujala scores improved from 58 to 93 (p < 0.002) and Fulkerson scores improved from 58 to 95 (p < 0.002) pre- and postoperatively respectively. The median return to work was 8 weeks and return to preoperative sport was 11 weeks. There were 2 revisions as a result of trauma. There were no instances of patellar fracture in this case series. Conclusions. MPFL reconstruction using a free gracillis tendon graft, oblique medial patella tunnel and interference screw femoral fixation appears to be an effective surgical intervention for patellar instability. This technique also reduces the risk of patellar fracture, a common shortcoming with many other techniques

Introduction. Malrotation of the femoral component is a cause of patellofemoral maltracking after total knee arthroplasty. We have developed a balanced gap technique in posterior stabilized total knee arthroplasty using an original instrument. Patellar instability is associated with an increased the tibial tubercle and the center of the groove (TT-TG) distance > 20 mm, and TT-TG is regarded as one index of a factor influencing congruity. To assess the influence on a patellofemoral joint by a modified gap technique, the purpose of this study is to compare the TT-TG distance before surgery and after total knee arthroplasty. Material and Methods. We explored the 30 knees, 25 patients (4 male and 21 female), who underwent total knee arthroplasties (NexGen LPS-Flex, fixed surface, Zimmer; Warsaw, USA) for osteoarthritis or rheumatoid arthritis. All procedures were performed through a medial parapatellar approach and a balanced gap technique used a developed versatile tensor device. We compared the preoperative and postoperative CT at a knee flexion angle of 30 degrees. To assess the force vector of the extensor mechanism, TT-TG distance and the proximal-distal distance between the entrance of the tracheal groove and the tibial tubercle (ET-TT distance) were measured in CT. The relation of both distances (TT-TG index) that divided TT-TG in ET-TT was calculated, because the TT-TG distance was affected by the individual knee size. Three dimensional Q-angle (θ) was also calculated using TT-TG distance and ET-TT distance, sinθ = TT-TG distance/ET-TT distance. (Figure 1). Results. The mean TT-TG distance of the pre-operation and post-operation was 14.6 ± 4.9 mm and 12.4 ± 3.9 mm, respectively. The mean ET-TT distance of the pre-operation and post-operation was 68.5 ± 7.3 mm and 71.8 ± 7.5 mm, respectively. The mean TT-TG index of the pre-operation and post-operation was 0.22 ± 0.07 and 0.17 ± 0.05, respectively. The mean θ was 12.1 ± 3.96 degrees and 9.84 ± 2.98 degrees, respectively. There were statistically differences of between pre-operation and post-operation. Discussion. TT-TG distance, TT-TG index and the three dimensional Q angle decreased after total knee arthroplasty using the modified gap technique. These results indicated that patellofemoral joint was realigned and stabilized, and the force vector of the extensor mechanism was decreased by the modified gap technique

Trochlear dysplasia is an important anatomical abnormality in symptomatic patellar instability. Our study assessed the mismatch between the bone and cartilaginous morphology in patients with a dysplastic trochlea compared with a control group. MRI scans of 25 knees in 23 patients with trochlear dysplasia and in 11 patients in a randomly selected control group were reviewed retrospectively, in order to assess the morphology of the cartilaginous and bony trochlea. Inter- and intra-observer error was assessed. In the dysplastic group there were 15 women and 8 men with a mean age of 20.4 years (14 to 30). The mean bony sulcus angle was 167.9. 0. (141. 0. to 203. 0. ), whereas the mean cartilaginous sulcus angle was 186.5. 0. (152. 0. to 214. 0. ; p < 0.001). In 74 of 75 axial images (98.7%) the cartilaginous contour was different from the osseous contour on subjective assessment; the cartilage exacerbated the abnormality. Our study shows that the morphology of the cartilaginous trochlea differs markedly from that of the underlying bony trochlea in patients with trochlear dysplasia. MRI is necessary in order to demonstrate the pathology and to facilitate surgical planning

The aim of this study was to evaluate the functional and clinical outcome following medial patello-femoral ligament reconstruction using autogenous hamstring tendon grafts for patellar instability. Over a 4 year period the senior author operated on 35 patients for lateral instability of the patella. The predominant initiating event was a sporting injury. Patients were evaluated clinically and functionally. The Fulkerson score was utilised pre and post operatively. The minimum follow up was 6 months, the mean follow up was 20 months. There were 18 males and 17 females. The mean age was 24.6 years. The mean pre-operative Fulkerson score was 59.3(range 6–100). The mean post operative Fulkerson score was 83.6(range 25–100), the mean improvement was 24.3. 24 patients returned to sporting activities. The main complications was one patient with a patella fracture that was stabilised with internal fixation, one patient requiring exploration and reinforcing the ligament which had attenuated. Both patients finally had a good clinical outcome. Our study has shown that symptomatic lateral instability of the patella can be effectively treated with a medial patello-femoral ligament reconstruction and result in overall good clinical and functional outcome. We would recommend this technique

Aims

The aim of this study was to evaluate medium-term outcomes and complications of the S-ROM NOILES Rotating Hinge Knee System (DePuy, USA) in revision total knee arthroplasty (rTKA) at a tertiary unit.

Aims: The purpose of the study was to assess the mid-term knee functional results after Medial Patellofemoral Ligament (MPFL) reconstruction with single semitendinosus autograft in patients with patellofemoral instability. Methods and Results: Knee function was assessed in 45 patients (46 knees) who underwent MPFL reconstruction with semitendinosus autograft. The tibial insertion of the semitendinosus was preserved whereas the free end, after stripping of the tendon from the musculo-tendinus junction was rerouted through the most distal part of the medial intermuscular septum proximally to the adductor tubercle, to the superomedial border of the patella, where it was fixed. Clinical and radiological evidence of patellar instability and MPFL rupture or deficiency was documented prior to surgery. Knee function was assessed preoperatively and postoperatively with the use of Kujala, Tegner, Lysholm and International Knee Documentation Committee (IKDC) scores. There were 34 male and 11 female patients with an average age of 32.5 years, ranging from 17 to 60 years. The minimum follow up was 2 years with an average of 33.5 months (range 24–54 months). Fourteen patients (30%) presented a degree of patellofemoral dysplasia. All knee functional scores significantly improved postoperatively. Kujala score improved from 57.7 to 77.1, Tegner score improved from 3.06 to 5.26, IKDC score improved from 51.2 to 75.44 and Lysholm score improved from 58.7 to 79.3. One of the patients required revision of the MPFL reconstruction due to traumatic redislocation of the patella. Conclusions: At a midterm follow-up, reconstruction of the MPFL with rerouting of the semitendinosus tendon is an effective method with improved function in all patients. Maximum improvement was achieved within the first six postoperative months. Heterogeneity of our population may have affected some of our results

Purpose of Study. To identify the degree of morphological change achievable following the Bereiter trochleoplasty and to establish whether these results are comparable with functional outcomes. Methods. Seventeen consecutive patients (19 knees) with patellar instability secondary to trochlear dysplasia underwent trochleoplasty, of which 12 knees (12 patients) were radiologically evaluated pre- and post surgery using axial CT and MRI imaging. Their mean age at time of surgery was 28.1 years (15 to 44). The mean follow-up was 2.2 years (0.5 to 5). The following four radiological outcomes were used: trochlear depth (TD), transverse patellar shift (TPS), lateral patellar inclination angle (LPIA) and sulcus angle (SA). All knees were assessed post-operatively using MRI. The axial CT images were reformatted which allowed for direct comparison with MRI. Each knee was radiologically evaluated twice by a senior musculoskeletal radiology consultant to increase data accuracy and assess for intra-observer reliability using the intraclass correlation coefficient (ICC). Functional outcomes consisted of the KOOS, Lysholm, Kujala and Tegner scores. Results. The ICC for all four radiological outcomes revealed high intra-observer reliability (0.89-0.92) suitable for clinical application. The results clearly show an increase in TD and TSP with median differences of 4mm (0.5-5) and 5.5mm (1.75-10) respectively. Decreases in SA and LPIA were observed with median differences of 14° (12.75-23) and 10.5° (7-21.75) respectively. These morphological changes resulted in improved patellar stability as exemplified by no re-dislocations and excellent functional outcomes: KOOS score 89.59 (81.97 to 93.36), Lysholm 97.5 (91.75 to 100), Kujala 93 (88.75-96.5) and Tegner Activity Scale increased from level 1 to 4 (p = 0.0002). Conclusion. This evaluation has shown the Bereiter trochleoplasty improves the radiological appearance of trochlear dysplasia close to normal in the proximal trochlea leading to improved patellofemoral congruency and excellent functional outcomes

Eighty-three Guepar valgus-hinge prostheses and 30 prostheses with collinear femoral and the tibial components were inserted in 97 patients at Vancouver General Hospital between March 1975 and May 1978. One hundred and nine arthroplasties were reviewed between January 1979 and April 1980, after an average follow-up of 19 months. It was found that the amount of bone resected made arthrodesis difficult, that there was a very high incidence of patellar instability and that the disintegration of the Silastic bumper created a severe chemical synovitis. The results were excellent in 32, good in 23, fair in 8, and poor in 30. Patellar subluxation occurred in 28 per cent of the valgus prostheses, and in 10 per cent with the straight prostheses; it did not occur with the straight prostheses in rheumatoid joints. The chemical synovitis led to failure with devastating complications necessitating further operations in some knees

To share our results following Medial Patellofemoral ligament (MPFL) reconstruction for patellar instability problems using ipsilateral semitendinosus graft anchored to the patella and the medial femoral condyle using biotenodesis screws. Study design and methods: 35 patients were assessed with a mean follow up of 18 months. All patients had preoperative true lateral knee x-ray, MRI or CT scan to look at trochlear dysplasia and the sulcus tuberosity distance. They all under went MPFL reconstruction using ipsilateral semitendinosus tendon. Two patients had sulcus tuberosity distance greater than 20 mm and they under went a tibial tubercle transfer in addition. Two patients had trochlear dysplasia and hence a trochlearplasty was also done. In skeletally mature patients the hamstrings tendon were anchored to the medial side of the patella in a 5×15mm blind tunnel using biotenodesis screw. This significantly reduces the risk of having patella fracture. All patients were treated by the same surgeon and assessments were performed by a different surgeon based on kujala scores and tegner scores. Results: Symptom relief was noted in all patients with in 3 months. No patient had patella dislocation or fracture after this procedure. They all had full range of movements and their kujala scores and tegner scores were good to excellent. Conclusion: MPFL reconstruction using hamstrings tendon anchored to the medial side of the patella and femur using biotenodesis screw gave a good result clinically and is associated with fewer complications including patellar fractures

Treatment of patellar instability in adolescents is controversial. Some investigators have advocated early repair of the medial structures, whereas others have treated this injury nonoperatively. The medial patellofemoral ligament, is a primary restrictor and stabilizer of the patella, and has acquired a significant role in the treatment of instability in children and adolescents. The authors present a prospective study of 39 consecutive patients (45 knees), without physeal closure, who underwent plasty of the medial patellofemoral ligament for the treatment of symptomatic patellofemoral instability with autologous Gracilis tendon, according to Chassaing’s technique. There were 26 female and 13 male patients with an average age of 15, 9 years. Mean follow-up was 44 months (6–65). All patients presented with clinical evident patellar tilt. This population presented a TA-GT within a normal range (12+/− 5 mm), but presented in 80% of cases a trochlear dysplasia. Clinical functional results were evaluated using the Kujala scale. Arthroscopic evaluation was systematically performed searching for intra articular injuries or patellar tilt. Early rehabilitation protocols were used in all cases. At the last follow up evaluation, 90% of the patients presented good or very good results. Kujala Score was 84, 5 +/−9,7 after surgery compared with 54,9+/−11,8 before surgery (p< 0,0001). There were 3 minor complications: 2 hematomas and 1 superficial infection that resolved without complications. Four patients kept complaining of residual anterior knee pain as result of patellar chondropathy that was diagnosed intra operatively. Three patients complained of graft donor site pain. One patient presented with a patellar dislocation three years after the surgery, and two patients still present clinical instability two years after the procedure. There was no stiffness in the knee in any patient. The technique presented in this study has allowed very good clinical results, with few complications, using a small incision to reconstruct in an isometric fashion, this important patellar stabilizer

Purpose: The Genesis II total knee arthroplasty system was introduced in 1996 as the next evolution in TKR design characterized by “built-in” femoral external rotation and improved trochlear design to optimize patellar tracking and femoral/tibial kinematics, as well as a polished tibial base plate and ethylene-oxide sterilized polyethylene to minimize wear. The purpose of this prospective study was to evaluate the long-term (minimum 10 year) clinical and radiographic results and survivorship of this novel TKA implant system. Method: Between 1996 and 1999, 478 Genesis II Primary TKRs were implanted and followed prospectively in 414 patients (mean follow-up 11.25±1.11 years). Diagnosis at index surgery included: 94% osteoarthritis, 5% inflammatory arthritis, 1% other diagnoses. Average age at index TKR was 68 years (range 38 to 93 years). There were 149 posterior cruciate retaining (31%) and 329 cruciate sacrificing (69%) knees implanted. Patella resurfacing was performed on 89% (432) of the cases. Sixty-seven deaths occurred prior to 10 years follow-up. Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Knee Society scores) and radiographs. Kaplan-Meier survival analysis was performed. Results: All health-related outcomes were significantly improved from preoperative with a mean Knee Society Score and WOMAC at last follow-up of 162 and 69, respectively. To date, 16 revision procedures have been performed. Revisions for infection included six two-stage revisions and two cases of irrigation & debridement with polyethylene exchange. In addition, there were three re-operations for stiffness and one for patellar instability. To date, there have been only two revisions for aseptic loosening and/or osteolysis. Excluding revisions for infection, the Kaplan-Meier survivorship analysis of the total knee system was 98.9±0.5% at five years and 98.2±0.6% at 10 years. Conclusion: The Genesis II total knee arthroplasty system, characterized by “built-in” femoral external rotation, improved trochlear design, a polished tibial base plate and ethylene-oxide sterilized polyethylene, has demonstrated excellent clinical & radiographic results and long-term survivorship (98% at 10 years) at our institution

Purpose of the study: TKA on genu valgum raises serious problems for the ligament balance. Excessive release of the lateral retracted ligaments exposes the knee to potential instability in the frontal plane. To resolve this problem and avoid implantation of a constrained TKA, we opted for osteotomy of the lateral condyle removing the insertion of the lateral collateral ligament and the popliteal muscle after release of the fascia lata. The purpose of our study was to evaluate the functional and radiographic outcomes of these patients. Material and methods: This was a retrospective study from 2002 to 2006. All patients with degenerative joint disease of the knee with severe and/or fixed genu valgum were included. These patients were implanted with a navigated posterostabilised Wallaby TKA (Navitrack) associated with osteotomy of the lateral condyle fixed with screws after acquisition of the ligament balance. The diagnosis and surgical history were noted. The preoperative alignement was determined on the full limb x-ray and from navigation data. The following variables were reviewed: polyethylene height, lowering of the lateral condyle, blood loss, operative time. The postoperative alignment was established at least one year after surgery. Intraoperative, postoperative and late complications were noted. The Knee Society function scores were used. Results: Fifteen patients, mean age 70 years were reviewed at mean 35 months. The mean duration of the operative time was 136 min with mean blood loss of 620 ml. The mean PE height was 13 mm. All operated knees were corrected with mean alignment improving from 17.71 to 1.5 valgus postoperatively. The function score improved from 35 preoperatively to 79 at last follow-up. There were no cases of patellar instability or secondary laxity. Two patients developed late reflex dystrophy. The only case of revision concerned one non-union of the lateral condyle (screw removed at four months) but had a function score of 85 at last follow-up. Discussion: Performing an osteotomy of the lateral condyle in complement with the navigated posterostabilised TKA for fixed genu valgum enabled good relaxation and satisfactory functional results so that totally constrained implants can be avoided

Axial radiographs were obtained under valgus and external rotation stress at 45° of knee flexion with and without contraction of the quadriceps muscle in order to assess the dynamics of patellar subluxation or dislocation. The radiography was performed on 82 knees in 61 patients with patellofemoral instability, and on 44 normal knees. The lateral patellofemoral angle and the congruence angle were measured and compared with the conventional Merchant views. Both parameters showed greater differences between symptomatic and normal knees on the stress radiographs obtained without quadriceps contraction. There was a major difference in the lateral patellofemoral angles between the groups, which clearly distinguished symptomatic knees from normal controls. Congruence angles on stress radiography had a significant correlation with the functional scores obtained after a period of conservative treatment and a positive correlation with the frequency of patellar subluxation. When the quadriceps contracted, two patterns of patellar shift were observed. While the patella reduced into the trochlear groove in all normal knees and about 70% of the symptomatic knees, contraction of the quadriceps caused further subluxation of the patella in the remaining symptomatic knees. All the knee joints which showed this displacement failed to respond to conservative treatment and eventually required surgical treatment. Thus, this technique of stress radiography is a simple, cost-effective and useful method of evaluating patellar instability and predicting the prognosis

Aims

Simultaneous bilateral total knee arthroplasty (TKA) has been used due to its financial advantages, overall resource usage, and convenience for the patient. The training model where a trainee performs the first TKA, followed by the trainer surgeon performing the second TKA, is a unique model to our institution. This study aims to analyze the functional and clinical outcomes of bilateral simultaneous TKA when performed by a trainee or a supervising surgeon, and also to assess these outcomes based on which side was done by the trainee or by the surgeon.

Aims: Patellar instability and painful patellar mal-tracking are common challenging conditions faced by a knee surgeon. Our purpose was to describe an arthroscopy assisted method of medial patellofemoral ligament reconstruction to address these conditions present our results using this modified technique. Materials & Method: Between April 2001 and December 2003, 22 knees in 20 consecutive patients underwent arthroscopically assisted MPFL reconstruction using an autologous hamstring tendon. There were 12 female and 8 male patients passed with a mean age of 29.9 years. The knees were assessed using Fulkerson’s and Kujala’s scoring systems and the mean follow-up period was 20.8 months (range 12–35). The technique uses a single hamstring tendon with undisturbed biological distal attachment, where the free end is routed through a longitudinal tunnel in the dorso-medial aspect of the patella and fixed to an isometric point near the medial femoral epicondyle using an interference screw. The position of femoral attachment is the most important factor in achieving an isometric graft. Results: There was a significant increase (p=< 0.0001) in mean Fulkerson score of 35.4 from a pre-operative value of 47.4 to a post-operative value of 82.9. Sixteen patients rated their knees as good or excellent and there was only one complication of complex regional pain syndrome. 11 of 13 patients who were keen on sports returned to their sports at a mean of 3.9 months (range 1–10). Conclusion: We report good results with this technique of medial patello femoral ligament reconstruction and would advocate it as an effective surgical option for patients with recurrent lateral instability as well as those with painful lateral mal-tracking

Background: The medial patellofemoral ligament (MPFL) is the principle medial stabilizer of the patella. It is damaged after traumatic patella dislocation. We describe a reproducible technique for MPFL reconstruction and our preliminary results at 12 months. Material-methods: 25 patients (19 men, 6 women; average age 26.9 years-old) with post-traumatic patellar instability underwent MPFL reconstruction at a mean post-injury interval of 22.3 months. Five patients had evidence of generalized laxity, 3 had trochlear dysplasia and 16 (64%) more than two episodes of dislocation. Arthroscopic assessment revealed associated chondral lesions in 88% and marked lateralization. The reconstruction was performed using ipsilateral semitendinosus tendon. With the distal attachment preserved, the proximal end is passed through the medial intermuscular membrane and secured to the medial border of the patella. Clinical pre- and post-operative assessments included IKDC, Tegner, Lysholm and Kujala scores. ICRS documentation recorded the contribution of articular cartilage damage, whereas Merchant views and MRI scans documented the abnormal radiological parameters and the damaged structures of the medial retinaculum respectively. Results: At a mean follow up period of 12 months (8–18 months) no cases of re-dislocation were recorded. The Tegner and IKDC scores averaged 4.2 and 46.9 pre-injury. Postoperatively they had improved to 7.7 and 86.5. The average postoperative Lyshom- and Kujala scores were 87 and 89 respectively. Re-operation was required in one patient after patellar fracture 8 weeks post reconstruction. Conclusion: Our preliminary results suggest surgical reconstruction of the MPFL provide a favorable early outcome for the treatment of post-traumatic patellofemoral instability and will form the basis for longer follow up in a larger cohort

Total knee arthroplasty (TKA) has produced excellent results, but many surgeons are hesitant to perform TKA in younger patients with isolated patellofemoral arthritis. In properly selected patients, patellofemoral arthroplasty (PFA) is an effective procedure with good long-term results. Contemporary PFA prostheses have eliminated many of the patellar maltracking problems associated with older designs, and short-term results, as described here, are encouraging. Long-term outcome and prospective trials comparing TKA to PFA are needed. Incidence. Isolated patellofemoral arthritis occurs in as many as 11% of men and 24% of women older than age 55 years with symptomatic osteoarthritis (OA) of the knee; Isolated patellofemoral arthritis found in 9.2% of patients older than age 40 years; 7% to 19% of patients experience residual anterior knee pain when TKA is done for isolated patellofemoral arthritis. Imaging. Weight bearing AP radiographs as supine radiographs can underestimate the extent of tibiofemoral arthritis; Midflexion posteroanterior radiographs to rule out posterior condylar wear; Lateral radiographs to identify the presence or absence of patella alta or baja; Axial radiographs identify the presence of trochlear dysplasia, patellar tilt or subluxation, and extent of patellofemoral arthritis; Magnetic resonance imaging and arthroscopic photographs should be reviewed if available. Indications. Osteoarthritis limited to the patellofemoral joint; Symptoms affecting daily activity referable to patellofemoral joint degeneration unresponsive to lengthy nonoperative treatment; Posttraumatic osteoarthritis; Extensive Grade-III chondrosis; Failed extensor unloading surgical procedure; Patellofemoral malalignment/dysplasia-induced degeneration. Contraindications. No attempt at nonoperative care or to rule out other sources of pain; Arthritis of greater than Grade 1 involving tibiofemoral articulation; Systemic inflammatory arthropathy; Osteoarthritis/chondrosis of the patellofemoral joint of Grade 3 or less; Patella baja; Uncorrected patellofemoral instability or malalignment; Uncorrected tibiofemoral mechanical malalignment; Active infection; Evidence of chronic regional pain syndrome or evidence of psychogenic pain; Fixed loss of knee range of motion, minimum 10–110 degrees ROM. Results. Majority of failures related to patellar instability from uncorrected patellar malalignment, soft-tissue imbalance, or component malposition; With improved implant designs tibiofemoral arthritis has become the primary source of failure; Failure from component subsidence or loosening occurring in <1% of knees. Our Series. Retrospective review 34 patients, 40 knees average 30 month follow-up using Natural Knee II Patello-femoral Joint System (Zimmer, Warsaw, IN); Average age 61, ranging from 34–84 years of age; Average subset KOOS scores were 93 for pain, 94 for symptoms, 94 for ADL's, 70 for sports and recreation, 82 for quality of life; Average pre-operative Tegner score 2.6, increasing to 4.7 post-operatively; 38/40 survival over 30 months with the two failures undergoing revision for traumatic injuries; No revisions to TKA; At most recent follow-up no progression of OA to involve tibiofemoral compartments; No evidence of component loosening

Recurrent patellar instability and anterior knee pain is a common problem after patellar dislocation. The medial patellofemoral ligament (MPFL) which contributes 40–80% of the total restraining forces is either attenuated or ruptured in these patients. Various techniques have been described in reconstructing this MPFL using hamstrings tendons. We wish to share our experience in treating these patients using ipsilateral semitendinosus tendon anchored to the medial femoral condyle and medial side of the patella using biotenodesis screws. Study design and methods: 15 patients were assessed with a mean follow up of 12 months. All patients had pre-operative true lateral knee x-ray, MRI or CT scan to look at trochlear dysplasia and the sulcus tuberosity distance. They all under went MPFL reconstruction using ipsilateral semitendinosus tendon. Two patients had sulcus tuberosity distance greater than 20 mm and they under went a tibial tubercle transfer in addition. Two patients had trochlear dysplasia and hence a trochleaplasty was also done. In skeletally mature patients the hamstrings tendon was anchored to the medial side of the patella in a 5x15mm blind tunnel using biotenodesis screw. This significantly reduces the risk of having patella fracture. In. children the graft was sutures to the soft tissues along the medial side of the patella and the medial femoral condyle. All patients were treated by the same surgeon and assessments were performed by a different surgeon based . on Kujala scores and Tegner scores. Results: Symptom relief was noted in all patients with in 3 months. No patient had patella dislocation or fracture after this procedure. They all had full range of movements and their Kujala scores and Tegner scores were good to excellent. Conclusion: MPFL reconstruction using hamstrings tendon anchored to the medial side of the patella and femur using biotenodesis screw gave a good result clinically and is associated with fewer complications including patellar fractures

Certain cases of patello-femoral maltracking can lead to articular surface wear. Though most can be treated non-operatively, where there is increasing wear surgical intervention may be necessary. Patellar tracking is difficult to assess and though several different types of maltracking or loading have been described, each case warrants precise assessment of the wear patterns. Without this knowledge a logical approach to realignment surgery is impossible. 60 consecutive cases (age range 18–50 years) presenting with anterior knee pain were arthroscoped over a 4 year period. These patients all had been selected with either patellar instability or surface wear indicated either clinically, a positive radiograph, bone scan or MRI. All patients were arthroscoped through standard anterolateral and antero-medial portals and also a superolateral and occasionally a supero-medial approach. The areas of articular damage were mapped on diagrams and recorded photographically. Patella views were taken in flexion and extension, and on passively stretching the patella medially and laterally. We found 6 distinct patterns of wear which appear to indicate 6 different maltracking abnormalities. The largest group, 46 patients, consisted of lateral trackers, with 21 patients demonstrating medial facet and lateral femoral condylar wear. Assessment of the articular surface of the patello-femoral groove from inferior portals is highly misleading and superior portals are needed for proper assessment. Medial facet wear can occur in lateral instability or medial compression. Lateral maltracking at engagement or distally are the commonest patterns

There are many procedures described to address recurrent patellar instability. This study evaluated the clinical and radiological outcome of a cohort of patients who had been treated using an algorithm based on plain radiography and CT findings to select the appropriate surgical procedure. 64 knees in 49 consecutive skeletally mature patients were treated by one surgeon over 4.8 years. They underwent either tibial tuberosity transfer and lateral release (TTT/LR) or lateral release alone (LR) based on their patellar height and tibial tuberosity trochlear groove (TTTG) distance. Of the knees that were reviewed, 33 underwent TTT/LR and 13 LR. 46 knees in 35 patients were evaluated clinically (42 in 32) or by phone (4 in 3) at a minimum of 1 year. Evaluation included the Kujala and IKDC (subjective and objective) scores and 31 knees underwent repeat radiological examination. There had been one or more further episodes of instability in 6/46 knees (13%). Only one knee had more than one further episode of instability. The rate of further instability was 8% in the LR group and 15% in the TTT/LR group. The mean overall subjective IKDC score was 80 (LR: 85, TTT/LR: 79). The mean overall objective IKDC scores were 79% A and 21% B (LR: 67% A, 33% B; TTT/LR: 83% A, 17% B). The mean overall Kujala score was 88 (LR:86, TTT/LR: 88). Three patients developed a clinically significant haemarthrosis (LR: 2, TTT/LR: 1), one of whom required an arthroscopic washout. The mean postoperative TTTG distance in the TTT/LR group was 8.5mm compared to the mean preoperative value of 16.2mm (p < 0001). However, there was also a mean reduction in the TTTG distance in the non operated knees of 2.6mm, suggesting a clinically relevant measurement error for this variable. The algorithm resulted in satisfactory outcomes for most patients. However, changes have subsequently been made in an attempt to further improve outcomes. These include using medial patellar glide to assess the requirement for a lateral release, measuring the TTTG distance with the knee extended, lowering the threshold for distal TTT, raising the threshold for medial TTT, and adding medial patellofemoral ligament reconstruction to the surgical options