AIM

Failure of a primary anterior cruciate ligament (ACL) reconstruction is associated with poor functional outcomes even after revision surgery. The aim of this study is to identify early predictors for failure, so that it may aid in recognition of at-risk patients.

There is mixed evidence in the literature regarding increasing age, ASA and BMI as risk factors for surgical site infection in orthopaedic surgery. To investigate the matter further, we examined 1055 wounds in 1008 patients in the Department of Trauma and Orthopaedic Surgery at University College London Hospital between 2000 and 2006. All patients with a minimum two-night stay were included. Data was collected by four designated research nurses. The age, height, weight and ASA status of each patient was recorded. All wounds were classified using ASEPSIS. This is a quantitative wound scoring method which is a summation of scores calculated from visual wound characteristics and the clinical consequences of infection.

Our results showed a strong linear association between age and ASEPSIS scores. Single variable regression analysis showed a t value of 3.32 and p value of 0.001. A similar linear association was seen between ASA grading and ASEPSIS scores. Single variable regression analysis showed a t value of 2.75 and p value of 0.006. The association between BMI and ASEPSIS scores was markedly different from that seen with age and ASA. The graph was U-shaped with patients with a BMI of 25-30 having the lowest average ASEPSIS scores. Patients with a lower and a higher BMI had higher average ASEPSIS scores. Single variable regression analysis was not significant since the relationship between BMI and ASEPSIS scores is not linear.

In conclusion, there are clearly defined patient groups who are at increased risk of developing a surgical site infection: older patients, patients with a higher ASA, and patients with both a low and high BMI. These patients should be targeted to reduce overall infection rates. This can be achieved by ensuring adequate antibiotic prophylaxis, having a low threshold to treat suspected infection and arranging regular follow-up.

Aim

The aim of our study was to assess lateral tracking of the patella with differing designs of Total Knee Arthroplasty (TKA) and compare to that of the native patella.

Hamstring muscle strain is a common sports related injury. It has been reported in a variety of sports, following acceleration or deceleration while running or jumping. Injury may vary from simple muscle strains to partial or complete rupture of the hamstring origin. Avulsion fracture of the ischial tuberosity has also been described. Simple hamstring muscle strains are treated conservatively. Surgical exploration and repair is currently advocated for partial or complete rupture of the hamstring origin. A few case series exists in literature suggesting the benefits of early intervention.

We report a series of 8 athletes who presented between 2002 and 2006 with complete tear of their hamstring origin. Avulsion of the ischial tuberosity was excluded in these cases. After confirming the diagnosis, early surgical exploration and repair or reattachment was performed. The patients were braced for 8 weeks. This was followed by specialist physiotherapy and a supervised rehabilitation programme over 6 months. All patients were followed up to monitor return to normal activities and sports. The sciatic nerve was scarred to the avulsed tendon in three cases. Neurolysis led to a rapid relief of symptoms. Cases where the hamstring origin had retracted more than 3 cm required a figure 7 incision. There were no major complications including nerve palsies.

An excellent functional outcome was noted by 12 months in all 8 patients. 7 of them returned to their previous level within 6-9 months of injury. One person despite a very good recovery, opted out of sports. No other complications were seen as a result of the surgical procedure. In conclusion, a tear of the origin of hamstring muscles is a significant injury. Early surgical repair and physiotherapy is associated with a good outcome and enables an early return to high level sports.

We aimed to measure cerebral microemboli load during total hip [THA] and knee arthroplasty (TKA) using transcranial Doppler ultrasound (TCD) and to investigate whether cerebral embolic load influences neuropsychiatric outcome. The timing of the microemboli was also related to certain surgical activities to determine if a specific relationship exists and the presence of a patent foramen ovale was investigated.

Patients undergoing primary THA and TKA underwent a battery of ten neuropsychiatric tests pre-operatively and at 6 weeks and 6 months post-operatively. Microembolic load was recorded using TCD onto VHS tape for subsequent analysis. Patent foramen ovale detection was performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre. The timing of specific surgical steps was recorded for each operation and embolic load calculated for that period. All patients were assessed for quality of life and orthopaedic outcome measures.

Aim: To investigate the relationship between patient psychological characteristics, adherence to rehabilitation physiotherapy and outcome at one year following anterior cruciate ligament reconstruction.

Methods: 75 consecutive patients undergoing ACL reconstruction by a single experienced surgeon received a pre-operative psychological assessment comprising of five questionnaires; Athletic Identity Measurement Scale (AIMS), Recovery Locus of Control Scale (RLCS), Self-Motivation Inventory (SMI), Hospital Anxiety and Depression Scale (HADS), and Short Form Social Support Questionnaire (SSQ6). Four functional questionnaires were completed pre-operatively by the patient; Subjective Knee Evaluation Form (IKDC 2000), Tegner Activity Scale (TAS), Lysholm Score (LS), and Lower Extremity Functional Score (LEFS). LEFS is a simple, sensitive subjective assessment tool which is sensitive to change. Final outcome was assessed by repeating the functional questionnaires at 1-year post-operatively following rehabilitation. Rehabilitation adherence was measured using the Sport Injury Rehabilitation Adherence Scale (SIRAS) and physiotherapy appointment attendance.

Results: The data were analysed using regression analysis (n=57). Self motivation score (R2= 0.142), a higher athletic identity (R2= 0.067), good social support (R2=0.170) and an internal locus of control or high self efficacy (R2=0.111) were all found to be positive predictors of final outcome. Poor self motivation and an external locus of control are associated with less successful final outcome.

Discussion and Conclusion: Self motivation and self efficacy are positive predictors of final outcome after ACL reconstruction. These aspects may be reinforced during rehabilitation. Patients with an external locus of control and poor self-motivation can be identified and their pre- and post-operative management may be adapted to achieve optimal outcome.

Introduction: In recent years, there has been a significant advancement in our understanding of femoro-acetabular impingement and associated labral and chondral pathology. Surgeons worldwide have demonstrated the successful treatment of these lesions via arthroscopic and open techniques. The aim of this study is to validate a simple and reproducible classification system for acetabular chondral lesions.

Methods: In our classification system, the acetabulum is first divided into 6 zones as described by Ilizalithurri VM et al [Arthroscopy 24(5) 534–539]. The cartilage is then graded as 0 to 4 as follows: Grade 0 – normal articular cartilage lesions; Grade 1 softening or wave sign; Grade 2 – cleavage lesion; Grade 3 – delamination and Grade 4 -exposed bone. The site of the lesion is further typed as A, B or C based on whether the lesion is 1/3 distance from acetabular rim to cotyloid fossa, 1/3 to 2/3 distance from acetabular rim to cotyloid fossa and > 2/3 distance from acetabular rim to cotyloid fossa.

For validating the classification system, six surgeons reviewed 14 hip arthroscopy video clips. All surgeons were provided with written explanation of our classification system. Each surgeon then individually graded the cartilage lesion. A single observer then compared results for observer variability using kappa statistics.

Results: We observed a high inter-observer reliability of the classification system with a kappa coefficient of 0.89 (range 0.78 to 0.91) and high intra-observer reliability with a kappa coefficient of 0.91 (range 0.89 to 0.96).

Discussion: In conclusion we have developed a simple reproducible classification system for acetabular cartilage lesions.

Introduction: The purpose of this study was to assess the efficacy and complications associated with revision hip arthroplasty undertaken in patients under the age group of 55 years.

Methods: A review of our institutions revision hip database showed that 430 revision hip arthroplasties undertaken over the past 9 years had a minimum follow up of 2 years. Of this 84 (56 female, 38 male) patients were under 55 years of age (range 2 to 8 years). The index procedures were preformed at an average age of 46 years (range 15 years to 54 years). The single major etiology of failure was aseptic loosening (74%), followed by infection (8%) and recurrent dislocation (7%). In majority of cases uncemented implants were used at revision surgery (91% femoral stem, 100% acetabular cups). Bone grafts were necessary in 39% of cases.

Results: There was 1% incidence of DVT requiring treatment and 1% incidence of deep infection requiring a further revision hip surgery. There were no cases of dislocation in this series. At final follow up satisfactory progress was noted in all cases with a significant improvement in Harris hip score (p < 0.05).

Discussion: In conclusion, revision of hip arthroplasty in patients below 55 years is associated with improvement in function and patient satisfaction. They perform better than older cohorts but not as good as primary THRs. The complication profile is comparable in the two groups.

Introduction: The radiographic evaluation of the antero-lateral femoral head is an essential tool for the assessment of cam type of femoroacetabular impingement. Computerised tomography (CT), magnetic resonance imaging and frog lateral plain radiograph views have all been suggested as imaging options for this type of lesion. The alpha angle is accepted as a reliable indicator of cam type of impingement and this may also be used as an assessment tool for successful operative correction of the cam lesion. The aim of our study was to analyse the reliability of The frog lateral view plain radiographs to analyse the alpha angle in cam femoroacetabular impingement.

Patients and Methods: Thirty two patients who presented with femoroacetabular impingement were studied. Interobserver reliability for assessment of alpha angles on frog lateral radiographic view was analysed using intraclass correlation coefficient. The alpha angles measured on frog lateral views using digital templating tools were compared to those measured on CT scans.

Results: A high interobserver reliability was noted for the assessment of alpha angles on frog lateral views with a correlation coefficient of 0.83. The average alpha angles measured on frog lateral views was 58.71 degrees (range 32 to 83.3). The average alpha angle measured on CT was 65.11 degrees (range 30 to 102). However, a poor correlation (Spearman r of 0.2) was noted between the measurements using the two systems.

Conclusions: Frog lateral plain radiographs are not reliable predictors of alpha angle. Various factors may be responsible for this such as the projection of the radiographs, patient positioning and quality of images. CT imaging may be necessary for accurate measurement of the alpha angle.

Background: Total hip replacement (THR) is one of the commonest operations in orthopaedic practice.

Literature review showed that 20–70% of patients who underwent THR needed 1–3 units of blood. Although safer than ever, allogeneic transfusion is still associated with risks for the recipient. There has been unsettled search for ways to reduce such blood loss and transfusion.

Tranexamic acid has been popularised as an effective way to reduce blood loss and subsequent blood transfusion.

Objectives: To investigate the value of Tranexamic acid in reducing blood loss and blood transfusion after THR and other clinical outcomes such as deep venous thrombosis (DVT), pulmonary embolism (PE), ischaemic heart diseases and mortality.

Patients and Methods: A systematic review and meta-analysis of published randomised and quasi-randomised trials which used tranexamic acid to reduce blood loss in hip arthroplasty was conducted. The data was evaluated using the generic evaluation tool designed by the Cochrane Bone, Joint and Muscle Trauma Group.

Results:

Blood loss

Seven studies (250 patients) were eligible for this outcome. Using Tranexamic acid reduced blood loss by an average of 155 ml (P-value < 0.00001, 95% CI (87–224), Heterogeneity I2 69 %.)

Blood transfusion

Nine studies (463 patients) were eligible for this outcome. Tranexamic acid led to a reduction in the proportion of patients requiring blood transfusion (Odds Ratio of 0.35, P- value < 0.00001, 95% CI (0.22–0.55), Heterogeneity I2 25 %.)

Other outcomes

There were no significant differences in the length of stay, DVT, PE, mortality, wound haematoma or infections between the study groups.

Conclusion: The use of Tranexamic acid in THR results in significant reduction of blood loss and blood transfusion.

Introduction: The presence of low levels of vitamin D in osteoarthritic patients has been reported as a substantial problem. We are not aware of any previous studies that have assessed the function of osteoarthritic patients undergoing joint replacement who are vitamin D deficient. This may be an important factor infiuencing preoperative function and postoperative outcome. The aim of this study was to investigate whether low vitamin D levels are associated with functional deterioration in patients with osteoarthritis of the hip undergoing total hip arthroplasty.

Methods: We measured plasma 25-hydroxyvitamin D3 (25(OH)D3) levels in 62 consecutive Caucasian patients undergoing total hip arthroplasty for osteoarthritis. The patients were divided into two groups based on whether they were vitamin D sufficient or deficient. The groups were matched for age, gender and ASA grade.

Results: The prevalence of vitamin D deficiency in our cohort of patients was comparable to recent population-based studies performed in the UK. Patients with vitamin D deficiency had lower preoperative Harris hip scores (Mann-Whitney test, p = 0.018) and were significantly less likely to attain an excellent outcome from total hip arthroplasty (Chi-square test, p = 0.038). Vitamin D levels were found to positively correlate with both preoperative and postoperative Harris hip scores.

Discussion: Our results warrant further study of vitamin D deficiency in patients undergoing joint replacement as it is a risk factor for suboptimal outcome which is relatively simple and cheap to correct.

Introduction: Blood transfusion is not uncommon in patients following joint replacement surgery. However, allogeneic transfusion is associated with potential risks ranging from immune mediated allergic reactions to transmission of blood-borne organisms. Furthermore its use has a significant economical impact on healthcare services.

Methods: A retrospective audit of the case notes and haematological records of 196 patients who underwent primary total hip (THR), resurfacing hip (BHR) or total knee replacement (TKR) was carried out. Patients were routinely cross-matched for 2 units of blood if their pre-operative haemoglobin (Hb) levels were < 12g/dL in our cohort. Patient details including age, sex, BMI, comorbidities, and ASA grade were also collected. Surgical parameters such as operation time, tourniquet time (for TKR procedures) and trigger haemoglobin levels (Hb) with timing of transfusion were noted. Statistical analysis was undertaken to identify risk factors for transfusion.

Results: Forty-seven (24%) patients were transfused in our cohort. 78.7% of these patients were appropriately transfused with a trigger Hb of < 8g/dL. Patients transfused with a trigger Hb of > 8g/dL were no different with respect to demographics, procedure type and comorbidities. The average postoperative time interval to transfusion was 2.1 days. Five patients required an intra-operative transfusion. The mean pre-operative Hb levels in transfused and non transfused patients were 12.4 g/dL and 13.5 g/dL respectively. The mean number of units transfused was 2.31. A total of 109 units of blood were used: of these 70 units were cross-matched pre-operatively.

Univariate analysis established a significant relationship between the need for postoperative transfusion and preoperative Hb levels (p< 0.0001), length of surgery (p=0.01), age (p=0.03), history of respiratory disease (p=0.028) and hypertension (p=0.01). There was no significant relationship with respect to ASA grade and procedure type. Multivariate logistic regression analysis revealed pre-operative Hb (p< 0.0001) and age (p=0.015) as the strongest predictors of the need for post-operative transfusion. There is a strong correlation between length of surgery and time interval to transfusion (p=0.037).

Conclusion: Utilisation rates of blood products after primary hip and knee arthroplasty procedures exceed that of what is available from pre-operative cross-matching. In our institution more than 20% of patients may have been transfused inappropriately based upon local guidelines. The decision to cross-match blood pre-operatively for elective arthroplasty procedures should be re-evaluated in light of both patient age and pre-operative Hb levels. Postoperative monitoring of Hb levels should be undertaken early in patients with a prolonged duration of surgery.

Introduction: Third generation fixation systems allow for the retightening of cables, and are associated with high rates of trochanteric union. This is a prospective study undertaken to evaluate the outcome of the first 40 patients treated with a third generation cable plate and trochanteric hook system.

Methods: 36 patients treated by two revision hip arthroplasty surgeons using a third generation cable plate system were enrolled and followed up. These included 28 females and 12 males with an average age of 64 (range: 48–91). Large hooks were used in 30 with an average of 4.8 cables (range: 4–9). The need to retighten cables intra-operatively was noted. Clinical and radiographic follow-up was undertaken at 2 years.

Results: A third generation fixation system was used for 16 peri-prosthetic fractures, 6 trochanteric non unions, 5 structural femoral allografts, 6 complex revisions and for trochanteric advancement in 3 cases. The first cable tightened was loose by the end of the procedure in the majority of cases and had to be retightened. There were no cases of fretting or cable breakage. Two further tro-chanteric non unions needed re-fixation and bone grafting in a further procedure

Discussion and Conclusion: Third generation cable system allow for re-tightening, as the cable is not damaged by the crimping mechanism. This facility appears critical as some retightening is invariably required in the process of applying this type of device. There were only 2 re-operations for trochanteric non unions, but the overall outcomes were otherwise excellent, with no fretting or cable breakage. Modern cable systems afford improved, more flexible trochanteric fixation possibilities.

Introduction: Up to 2% of total knee arthroplasties (TKA) are still complicated by infection. This leads to dissatisfied patients with poor function, and has far-reaching social and economic consequences. The challenge in these cases is the eradication of infection, the restoration of full function and the prevention of recurrence. We report the outcome of prosthesis sparing early aggressive debridement in the acutely infected TKA.

Methods: We studied 29 consecutive patients referred with acutely infected TKA (18 primaries, 11 revisions) which occurred within 6 weeks of the index operation or of haematogenous spread. Microbiology confirmed bacterial colonization in all cases with 20 early postoperative infections and 9 cases of acute haematogenous spread. All patients underwent aggressive open debridement, a thorough synovectomy and a change of insert. Antibiotics were continued until inflammatory markers and the plasma albumin concentration returned to within normal limits.

Results: Three patients required multiple washouts. 8 patients needed a two stage revision. 21 patients returned to their expected functional level without removal of the implants and with no radiographic evidence of prosthetic failure. At a minimum 2 years follow-up, we had a 72% infection control rate. The outcome was significantly better in patients treated in the first 120 hours after presentation.

Discussion and Conclusion: Our data suggests that there is a role for early aggressive open debridement in acute infections after TKA with an excellent chance of prosthesis salvage.

Introduction: Rupture of the anterior cruciate ligament (ACL) is a serious injury associated with symptomatic instability of the knee. There is an increasing trend for confirmation of diagnosis with magnetic resonance imaging (MRI) before proceeding to reconstruction. The overall sensitivity and specificity of diagnosis using this modality is more than 95%. It is however observer-dependent. We have developed a simple 4 point recognition card to increase the pick-up rate of this injury for professionals without specific radiological training such as orthopaedic trainees. The aim of this study was to determine how much improvement could be achieved using this card and whether any change was sustained.

Methods: 20 participants (orthopaedic trainees surgeons and medical students) were shown 20 MRI scans of the knee (10 with complete ACL ruptures and 10 with normal ACLs) and asked which scans were demonstrative of ACL pathology. Each participant was then randomly allocated to either having verbal teaching in the standard fashion about detection of ACL injuries [Group 1] or given written cards detailing a 4 point recognition plan for recognising ACL injuries on MRI [Group 2]. A repeat test of MRI scans was performed on each participant immediately after the teaching session and at 3 weeks.

Results: The mean time taken to teach Group A was 14 mins and Group B was 11 mins (p < 0.05). The mean number of correct diagnoses was 2.7/10 in Group A and 3.1/10 in Group B pre-intervention (p > 0.05). Immediately following intervention, there were 6.1 correct diagnoses in Group A and 8.2 in Group B (p < 0.05). At 3 weeks, there were 3.4 correct diagnoses in Group A and 7.9 in Group B (p < 0.05). The difference in number of correct diagnoses at 3 weeks compared to immediately following intervention was significant in Group A (p < 0.05), but not in Group B (p > 0.05).

Conclusions: The results support the use of the 4 point recognition card as to tool for increasing the pick-up of ACL injuries on MRI. It offers advantages over standard teaching Methods: since it takes less time to teach and the necessary information is retained to a greater degree than with traditional teaching methods.

Introduction: The bearing surface of total hip arthroplasty (THA) is a key factor in implant survivorship. Ceramic bearings have enhanced wear properties though are prone to fracture and thus Oxinium has been developed as an alternative. The aim of our study was to compare the its wear properties against cobalt-chrome which is currently the most widely used femoral head bearing surface in THA.

Methods: We prospectively randomized 270 consecutive patients undergoing THA at one institution into three groups: Groups I, II and III. Group I received a cobalt-chrome femoral head and cross-linked poly-ethylene (XLPE) liner; Group II received an oxinium femoral head and ultrahigh molecular weight polyeth-ylene (UHMWPE) liner; Group III received an oxinium femoral head and cross-linked polyethylene liner. 32 mm heads were used in all the cases. Patients were longitidunally followed up with clinical evaluation and standardised radiographs of the pelvis and hip. Using DICOMeasure software, we calculated the linear and volumetric wear rate for each group to determine if a difference existed.

Results: The demographics and comorbid conditions were similar between the groups. The survivorship of all components was 100% in all groups at 2 years. No patients were lost to follow-up. After the first 6 months of creep, the rate of linear wear over 2 years was 0.16mm for Group I, 0.10mm for Group II, and 0.06mm for Group III. ANOVA testing demonstrates statistical significance between the groups (P < 0.05).

Discussion and Conclusion: Our results demonstrate that the wear rate using 32mm Oxinium heads is significantly lower than that for cobalt-chrome heads and this effect is dramatically enhanced when used in combination with highly cross linked polyethylene.

We investigated the hypothesis that autologous bone marrow stromal cells (BMSC) sprayed on the surface of acetabular cups would improve bone formation and bone implant contact.

Total hip replacements were implanted in 11 sheep, randomly assigned to receive either acetabular implants sprayed with autologous BMSCs suspended in fibrin (study group) or fibrin only (control group). Sheep were sacrificed after six months and the acetabulum with the implant was retrieved and prepared for undcalcified histology. Implant bone contact in both groups was compared, by microscopically noting the presence or absence of new bone or fibrous tissue along the implant at 35 consecutive points (every 1000 μm). The observers undertaking the histological analysis were blinded.

Significantly increased bone implant contact was noted in the BMSC treated group 30.71% ± 2.95 compared to the control group 5.14% ± 1.67 (p = 0.014). The mean thickness of fibrous tissue in contact with the implant was greater at the periphery 887.21mm ± 158.89 and the dome 902.45mm ± 80.67 of the implant in the control group compared to the BMSC treated group (327.49mm ± 20.38 at the periphery and 739.1 mm ±173.72 at the centre). Conversely direct bone contact with the implant surface was significantly greater around the cups with stem cells.

BMSC sprayed on surface of implants improves bone implant contact. Spraying acetabular cups using stem cells could be used in humans where acetabular bone contact is compromised such as in revision procedures.

Our aim was to ascertain the opinion of Orthopaedic Consultants, General Practitioners, and Patients on the proposed primary care based follow up of joint replacements.

An email questionnaire was sent Orthopaedic Consultants registered with the BOA. Responders had to answer simple questions regarding follow up practices after hip and knee arthroplasty and safe alternatives to the existing system. General practitioners in London were sent a different questionnaire to assess their familiarity with follow up of arthroplasty patients and their competence in identifying complications. Finally, arthroplasty patients were directly questioned on their preference for follow up.

Eigthy-one Orthopaedic Consultants who undertake lower limb arthroplasty responded, 89.06% advocated follow up and review of radiographs by the surgeon. The Arthroplasty Practitioner, the Radiologist and the Physiotherapist were deemed suitable for follow up of patients by 50%, 14.06% and 4.69 % respectively. All responders unanimously disagreed with initial follow up by General Practitioners (0%). However, after a 12 month review, 30.15% thought primary arthroplasty patients could be discharged to the care of their General Practitioner and 11.11% were happy to discharge revision arthroplasty patients. Of the 52 General Practitioners who returned our questionnaire, only 37% were confident of interpreting symptoms related to prosthetic loosening or infection and 98% did not feel competent identifying radiological changes after arthroplasty. 94% of the General Practitioners did not think that they would be happy to follow up arthroplasty patients even if they were offered further training. The reasons for this were lack of specialty skills, work-load concerns, funding issues and surgeons’ duty of care towards the patient. All of the 104 patients who were questioned preferred to be followed up by the arthroplasty team.

In conclusion, Orthopaedic Surgeons, General Practitioners and patients prefer a hospital based dedicated Orthopaedic team for the post operative follow-up of arthroplasty patients.

Background: Cam-type femoroacetabular impingement (FAI) is becoming more recognized. Cartilage lesions of the acetabulum and labral tears are frequently encountered. The goal of this study was to accurately describe and communicate these injuries and thus providing a standard for reporting injury, management, and outcome.

Methods: We evaluated acetabular cartilage lesions and labral tears found during hip arthroscopy in 52 patients with radiological signs of cam-type FAI. They were graded according to the morphology and extent of the lesion. The labral tears were described according to the classification by Lage.

Results: Eleven patients (21.2%) had normal cartilage, 14 (26.9%) had a grade 1, 17 (32.7%) a grade 2, 6 (11.5%) a grade 3, and 4 (7.7%) a grade 4 lesion. Labral tears were found in 31 patients (59.6%). There was a high correlation between age and the presence and extent of acetabular cartilage and labral lesions (r=0.70; p< 0.0001 and r=0.45; p< 0.001 respectively). There was also a high correlation between the extent of the acetabular cartilage lesion and the presence of labral lesions (r=0.62; p< 0.0001).

Conclusion: In our study there was a high prevalence of associated injuries (86.5%) in cam-type FAI. Despite the recognized consequences of associated lesions on treatment and outcome, no classification system includes this aspect of FAI. Based on our findings, we developed a system to grade acetabular cartilage lesions according to their morphology and extent. This should provide the surgeon with a standardized tool to better describe the full extent of the injury and treat it accordingly.