Autologous bone grafting in combination with autologous chondrocyte implantation yields favourable outcomes in the treatment of osteochondral defects of the knee: A systematic literature review.

PURPOSE: This study addresses the gap in the current literature by evaluating the combined treatment of autologous bone grafting and autologous chondrocyte implantation (ABCI) for osteochondral defects of the knee. It aims to evaluate clinical outcomes against methodological quality and to summarize histological results and surgical techniques. METHODS: A thorough search was conducted across Pubmed, Cochrane and Embase databases. Studies reporting clinical outcomes of ABCI for osteochondral defects of the knee were included. Patient-reported outcome measures (PROMs), failure rates, methodological quality and potential conflicts of interest were evaluated. Histological results and surgical techniques were summarized. RESULTS: Eighteen studies with 344 analyzed patients met the eligibility criteria for inclusion. All studies showed a significant improvement (p < 0.05) across different PROMs (subjective International Knee Documentation Committee score, Cincinnati Knee Rating System, Visual Analogue Scale, Lysholm Score, Tegner Activity Scale, Knee injury and Osteoarthritis Outcome Score and Knee Society Score) compared to the preoperative status. Failure rates ranged from 0% to 17.6%, with a mean follow-up of 73.2 months (range: 9.0-143.6 months). Methodological quality was low to medium, including only one comparative study. Six studies reviewed reported a potential conflict of interest. The histological assessment showed effective bonding between autologous chondrocytes and bone graft. A large degree of variability was observed in the operative technique used. CONCLUSION: The current literature suggests that ABCI yields good clinical outcomes at mid- to long-term follow-up with favourable histological results for osteochondral defects of the knee. However, future research should focus on high-quality comparative studies to better guide treatment choices. Introducing ABCI as the standard abbreviation may enhance clarity in future research. LEVEL OF EVIDENCE: Level IV.

In idiopathic scoliosis distances of spinal cord to thoracic pedicle are within 2 mm in a large region of the thoracic apex.

Despite a 15% misplacement rate of screws in idiopathic scoliosis surgery, little is known about the relationship between pedicles and nerve structures in the entire thoracic curve. This study aimed to explore the spinal cord's proximity to the pedicle wall at each thoracic vertebra in the entire thoracic curve, while considering different anatomical changes. Spinal cord to medial pedicle distances were measured on magnetic resonance imaging in 73 patients who underwent posterior spinal fusion with pedicle screw instrumentation. Associations with different variables were examined. A total of 51 patients (69.9%) showed a distance within 2 mm at the apex vertebra on the concave side, more than 50% had a distance within 2 mm in the next thoracic vertebra level above and below, and more than 25% two levels above and below. Weak correlations were found between proximity of the spinal cord at the apex vertebra and vertebra's level and Cobb angle on the concave side (r = - 0.310, P = 0.008, r = 0.380, P = 0.001, respectively). These results emphasize the importance of thorough assessment when placing thoracic pedicle screws in idiopathic scoliosis patients. Further research is warranted to develop surgical strategies aimed at preventing potentially neurological complications resulting from screw misplacement.

Comparison of the early postoperative outcomes of cementless and cemented medial unicompartmental knee arthroplasty.

Aims: The primary objective of this registry-based study was to compare patient-reported outcomes of cementless and cemented medial unicompartmental knee arthroplasty (UKA) during the first postoperative year. The secondary objective was to assess one- and three-year implant survival of both fixation techniques. Methods: We analyzed 10,862 cementless and 7,917 cemented UKA cases enrolled in the Dutch Arthroplasty Registry, operated between 2017 and 2021. Pre- to postoperative change in outcomes at six and 12 months' follow-up were compared using mixed model analyses. Kaplan-Meier and Cox regression models were applied to quantify differences in implant survival. Adjustments were made for patient-specific variables and annual hospital volume. Results: Change from baseline in the Oxford Knee Score (OKS) and activity-related pain was comparable between groups. Adjustment for covariates demonstrated a minimally greater decrease in rest-related pain in the cemented group (ß = -0.09 (95% confidence interval (CI) -0.16 to -0.01)). Cementless fixation was associated with a higher probability of achieving an excellent OKS outcome (> 41 points) (adjusted odds ratio 1.2 (95% CI 1.1 to 1.3)). The likelihood of one-year implant survival was greater for cemented implants (adjusted hazard ratio (HR) 1.35 (95% CI 1.01 to 1.71)), with higher revision rates for periprosthetic fractures of cementless implants. During two to three years' follow-up, the likelihood of implant survival was non-significantly greater for cementless UKA (adjusted HR 0.64 (95% CI 0.40 to 1.04)), primarily due to increased revision rates for tibial loosening of cemented implants. Conclusion: Cementless and cemented medial UKA led to comparable improvement in physical function and pain reduction during the initial postoperative year, albeit with a greater likelihood of achieving excellent OKS outcomes after cementless UKA. Anticipated differences in early physical function and pain should not be a decisive factor in the choice of fixation technique. However, surgeons should consider the differences in short- and long-term implant survival when deciding which implant to use.

Preservation of prearthritic coronal knee phenotype and prearthritic coronal alignment yielded improved Kujala scores following ligament-guided medial unicompartmental knee arthroplasty.

PURPOSE: There is a lack of literature evaluating outcomes of the ligament-guided approach in medial unicompartmental knee arthroplasty (UKA). An improved comprehension of the distribution of coronal plane alignment of the knee (CPAK) phenotypes and sagittal tibial wear patterns and their associations with patient-reported outcome measures (PROMs) and implant survivorship could provide insights into its further application in daily practice. METHODS: A registry was reviewed for patients with a minimal 2-year follow-up who underwent robotic-assisted, ligament-guided, medial UKA between 2008 and 2016. Survivorship and postoperative PROMs were collected. CPAK phenotypes and sagittal tibial wear patterns were determined. Survivorship, Knee Injury and Osteoarthritis Outcome Score (KOOS), Kujala and patient satisfaction were compared between phenotypes and sagittal tibial wear patterns. RESULTS: A total of 618 knees were included at a mean follow-up of 4.1 [2.0-9.6] years. Four-year conversion to the TKA survival rate was 98.9% [98.4%-99.3%] and 94.3% [93.3%-95.3%] for all-cause revision. Patients with preservation of the CPAK phenotype (84.5 ± 14.9, 81.8 ± 15.5, p = 0.033) and restoration of prearthritic coronal alignment (84.1 ± 14.9, 81.7 ± 15.9, p = 0.045) had a significantly higher Kujala score. No other significant differences in survivorship or PROMs were observed between phenotypes or sagittal tibial wear patterns. Additionally, no difference in survival rates was observed between preserved or altered phenotypes. CONCLUSION: This study demonstrated that preservation of CPAK phenotype and preservation of prearthritic coronal alignment yielded a significantly higher Kujala score. No other significant differences in PROMs or implant survivorship were observed, suggesting that robotic-assisted, ligament-guided medial UKA provides equal outcomes for all observed phenotypes and sagittal tibial wear patterns in medial compartment OA as long as preoperative CPAK phenotype is preserved postoperatively. LEVEL OF EVIDENCE: Level III.

Restoration or relative overcorrection of pre-arthritic coronal alignment leads to improved results following medial unicompartmental knee arthroplasty.

PURPOSE: A pre-arthritic alignment strategy for medial unicompartmental knee arthroplasty (UKA) aims to restore a patient's native lower limb alignment which may translate into improved outcomes. This study aimed to assess whether patients with pre-arthritically aligned knees versus patients with non-pre-arthritically aligned knees demonstrated improved mid-term outcomes and survivorship following medial UKA. The hypothesis was that pre-arthritic alignment in medial UKA would lead to better postoperative outcomes. METHODS: A retrospective study of 537 robotic-assisted fixed-bearing medial UKA was conducted. During this procedure, the surgical goal was to restore pre-arthritic alignment guided by re-tensioning of the medial collateral ligament (MCL). For study purposes, coronal alignment was retrospectively evaluated using the mechanical hip-knee-ankle angle (mHKA). Pre-arthritic alignment was estimated through the arithmetic hip-knee-ankle (aHKA) algorithm. Knees were grouped according to the difference between postoperative mHKA and estimated pre-arthritic alignment (i.e., mHKA - aHKA) as Group 1 (pre-arthritically aligned: mHKA restored within 2.0° of the aHKA), Group 2 (mHKA > 2.0° overcorrected relative to the aHKA), or Group 3 (mHKA > 2.0° undercorrected relative to the aHKA). Outcomes included the Knee Injury and Osteoarthritic Outcome Score for Joint Replacement (KOOS, JR), Kujala, proportions of knees achieving the patient acceptable symptom state (PASS) for these scores, and survivorship. PASS thresholds for KOOS, JR and Kujala were determined using a receiver operating characteristic curve method. RESULTS: A total of 369 knees were categorized as Group 1, 107 as Group 2, and 61 as Group 3. At 4.4 ± 1.6 years follow-up, mean KOOS, JR was comparable among groups, while Kujala was significantly worse in Group 3. The proportion of knees achieving the PASS for Kujala (76.5 points) was lower in Group 3 (n = 32; 59%) compared to Group 1 (n = 260; 74%) (p = 0.02). 5-year survivorship was higher in Group 1 and Group 2 (99% and 100%, respectively) compared to Group 3 (91%) (p = 0.04). CONCLUSION: Pre-arthritically aligned knees and knees with relative overcorrection from their pre-arthritic alignment following medial UKA demonstrated improved mid-term outcomes and survivorship compared to knees with relative under correction from their pre-arthritic alignment. These results encourage restoring or relatively overcorrecting pre-arthritic alignment to optimize outcomes following medial UKA, and caution against under correction from the pre-arthritic alignment. LEVEL OF EVIDENCE: IV, case series.

Majority of competitive soccer players return to soccer following hip arthroscopy for femoroacetabular impingement: female and older aged players are less likely to return to soccer.

PURPOSE: To determine return to soccer rates and soccer performance in a large cohort of competitive soccer players after hip arthroscopic surgery for the treatment of femoroacetabular impingement (FAI) and to identify possible risk factors associated with not returning to soccer. METHODS: An institutional hip preservation registry was retrospectively reviewed for patients identified as competitive soccer players who underwent primary hip arthroscopy for FAI performed between 2010 and 2017. Patient demographics and injury characteristics as well as clinical and radiographic findings were recorded. All patients were contacted for return to soccer information using a soccer-specific return to play questionnaire. Multivariable logistic regression analysis was used to identify potential risk factors for not returning to soccer. RESULTS: Eighty-seven competitive soccer players (119 hips) were included. 32 players (37%) underwent simultaneous or staged bilateral hip arthroscopy. The mean age at surgery was 21.6 ± 7.0 years. Overall, 65 players (74.7%) returned to soccer, of which 43 players (49% of all included players) returned to pre-injury level of play or better. Most common reasons for not returning to soccer were pain or discomfort (50%) followed by fear of re-injury (31.8%). The mean time to return to soccer was 33.1 ± 26.3 weeks. Among 22 players who did not return to soccer, 14 (63.6%) reported satisfaction from surgery. Multivariable logistic regression analysis revealed female players (odds ratio [OR] = 0.27; confidence interval [CI] = 0.083 to 0.872; p = 0.029) and older aged players (OR = 0.895; 95% CI = 0.832 to 0.963; p = 0.003) were less likely to return to soccer. Bilateral surgery was not found to be a risk factor. CONCLUSION: Hip arthroscopic treatment for FAI in symptomatic competitive soccer players allowed three-quarters of them to return to soccer. Despite not returning to soccer, two-thirds of players who did not return to soccer were satisfied with their outcome. Female and older aged players were less likely to return to soccer. These data can better guide clinicians and soccer players with realistic expectations related to the arthroscopic management of symptomatic FAI. LEVEL OF EVIDENCE: III.

Robotic-assisted medial unicompartmental knee arthroplasty restores estimated pre-arthritic coronal limb alignment: A retrospective cohort study.

BACKGROUND: Robotic-assisted medial unicompartmental knee arthroplasty (UKA) aims to restore pre-arthritic (constitutional) limb alignment, by re-tensioning of the medial collateral ligament (MCL). This study aimed to determine whether pre-arthritic coronal alignment was restored following robotic-assisted medial UKA in patients with medial compartment osteoarthritis. METHOD: A retrospective study was undertaken, including 102 patients with a unilateral robotic-assisted medial UKA and a contralateral unaffected knee. Both the validated arithmetic hip-knee-ankle angle (aHKA) and alignment of the contralateral unaffected knee were used to estimate pre-arthritic alignment. The aHKA is a radiographic method to estimate the pre-arthritic mechanical hip-knee-ankle angle (mHKA). To verify restoration of pre-arthritic alignment, postoperative mHKA was compared to the aHKA. Additionally, postoperative mHKA, joint line congruence (JLCA), and knee joint line obliquity (KJLO) angles were compared between the operative and contralateral unaffected knee. Equivalence between postoperative and pre-arthritic alignment was assessed through the two-one-sided t-test (TOST), using equivalence margins of ±2.0°. RESULTS: Postoperative mHKA was equivalent to the aHKA (mean difference -0.38°, 90% CI -0.69 to -0.07;p < .001), with 93 knees (91%) restored within 3.0° of their aHKA. Postoperative mHKA, JLCA and KJLO were equivalent between the operative and contralateral unaffected knees, with mean differences of -0.65°, -0.65°, and -0.40°, respectively; all p < .001. CONCLUSIONS: Postoperative and pre-arthritic coronal alignment were equivalent following robotic-assisted medial UKA, with 91% of knees restored within 3.0° of their pre-arthritic mechanical axis. These results demonstrate that both mechanical alignment and joint line congruence are restored by MCL re-tensioning in patients undergoing robotic-assisted medial UKA for medial compartment osteoarthritis.

Comparable incidence of periprosthetic tibial fractures in cementless and cemented unicompartmental knee arthroplasty: a systematic review and meta-analysis.

PURPOSE: (I) To determine the incidence of periprosthetic tibial fractures in cemented and cementless unicompartmental knee arthroplasty (UKA) and (II) to summarize the existing evidence on characteristics and risk factors of periprosthetic fractures in UKA. METHODS: Pubmed, Cochrane and Embase databases were comprehensively searched. Any clinical, laboratory or case report study describing information on proportion, characteristics or risk factors of periprosthetic tibial fractures in UKA was included. Proportion meta-analysis was performed to estimate the incidence of fractures only using data from clinical studies. Information on characteristics and risk factors was evaluated and summarized. RESULTS: A total of 81 studies were considered to be eligible for inclusion. Based on 41 clinical studies, incidences of fractures were 1.24% (95%CI 0.64-2.41) for cementless and 1.58% (95%CI 1.06-2.36) for cemented UKAs (9451 UKAs). The majority of fractures in the current literature occurred during surgery or presented within 3 months postoperatively (91 of 127; 72%) and were non-traumatic (95 of 113; 84%). Six different fracture types were observed in 21 available radiographs. Laboratory studies revealed that an excessive interference fit (press fit), excessive tibial bone resection, a sagittal cut too deep posteriorly and low bone mineral density (BMD) reduce the force required for a periprosthetic tibial fracture to occur. Clinical studies showed that periprosthetic tibial fractures were associated with increased body mass index and postoperative alignment angles, advanced age, decreased BMD, female gender, and a very overhanging medial tibial condyle. CONCLUSION: Comparable low incidences of periprosthetic tibial fractures in cementless and cemented UKA can be achieved. However, surgeons should be aware that an excessive interference fit in cementless UKAs in combination with an impaction technique may introduce an additional risk, and could therefore be less forgiving to surgical errors and patients who are at higher risk of periprosthetic tibial fractures. LEVEL OF EVIDENCE: V.

Patient-Reported Outcomes and Factors Associated with Achieving the Minimal Clinically Important Difference After ACL Reconstruction: Results at a Mean 7.7-Year Follow-up.

BACKGROUND: Analyzing outcomes and the minimal clinically important difference (MCID) after anterior cruciate ligament reconstruction (ACLR) is of increased interest in the orthopaedic literature. The purposes of this study were to report outcomes after ACLR at medium to long-term follow-up, identify the threshold preoperative outcome values that would be predictive of achieving the MCID postoperatively, and analyze outcome maintenance at medium to long-term follow-up after ACLR. METHODS: Active athletes who underwent ACLR were identified in an institutional ACL registry. Patient-reported outcome measures (PROMs) were administered preoperatively and at the 2-year and >5-year postoperative follow-up; measures included the International Knee Documentation Committee (IKDC) form, the 12-item Short Form Health Survey (SF-12) Physical Component Summary (PCS) and Mental Component Summary (MCS), and Lysholm scale. We calculated the MCID from baseline to each of the 2 follow-up periods (2-year and mean 7.7-year). Logistic regression was performed to investigate factors associated with achievement of the MCID. RESULTS: A total of 142 patients (mean follow-up, 7.7 years [range, 6.6 to 9.1 years]) underwent ACLR. The mean age and body mass index at the time of surgery were 27.2 ± 13.0 years and 23.2 ± 3.0 kg/m2, respectively. Final postoperative outcome scores improved significantly from baseline for the IKDC (50.9 ± 14.7 to 87.9 ± 11.2), SF-12 PCS (41.6 ± 8.9 to 55.6 ± 3.2), and Lysholm scale (62.2 ± 17.6 to 90.5 ± 10.3) (p < 0.0001), while the SF-12 MCS did not improve significantly (54.2 ± 8.0 to 54.4 ± 6.0) (p = 0.763). Between 2- and >5-year follow-up, the SF-12 PCS showed significant improvement (54.6 ± 4.5 to 55.6 ± 3.2; p = 0.036), while no change was noted in the IKDC (87.6 ± 11.1 to 87.9 ± 11.2), SF-12 MCS (55.5 ± 5.3 to 54.4 ± 6.0), and Lysholm scale (89.8 ± 10.6 to 90.5 ± 10.3) (p ≥ 0.09). At the time of final follow-up, the MCID was achieved by 94.7% of patients for the IKDC, 80.8% for the Lysholm, 79.0% for the SF-12 PCS, and 28.2% for the SF-12 MCS. At 2-year follow-up, 95.3% of patients were either "very" or "somewhat" satisfied with their surgery, compared with 88.6% at the time of final follow-up. CONCLUSIONS: We found a high level of maintained function following ACLR. The IKDC, SF-12 PCS, and Lysholm scores improved significantly after ACLR at the time of final follow-up and were not significantly different between follow-up periods. Approximately 95% and 89% of patients reported being satisfied with the outcome of surgery at the 2-year and final follow-up, respectively. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Risk of revision for medial unicompartmental knee arthroplasty according to fixation and bearing type : short- to mid-term results from the Dutch Arthroplasty Register.

AIMS: Uncemented mobile bearing designs in medial unicompartmental knee arthroplasty (UKA) have seen an increase over the last decade. However, there are a lack of large-scale studies comparing survivorship of these specific designs to commonly used cemented mobile and fixed bearing designs. The aim of this study was to evaluate the survivorship of these designs. METHODS: A total of 21,610 medial UKAs from 2007 to 2018 were selected from the Dutch Arthroplasty Register. Multivariate Cox regression analyses were used to compare uncemented mobile bearings with cemented mobile and fixed bearings. Adjustments were made for patient and surgical factors, with their interactions being considered. Reasons and type of revision in the first two years after surgery were assessed. RESULTS: In hospitals performing less than 100 cases per year, cemented mobile bearings reported comparable adjusted risks of revision as uncemented mobile bearings. However, in hospitals performing more than 100 cases per year, the adjusted risk of revision was higher for cemented mobile bearings compared to uncemented mobile bearings (hazard ratio 1.78 (95% confidence interval 1.34 to 2.35)). The adjusted risk of revision between cemented fixed bearing and uncemented mobile bearing was comparable, independent of annual hospital volume. In addition, 12.3% of uncemented mobile bearing, 20.3% of cemented mobile bearing, and 41.5% of uncemented fixed bearing revisions were for tibial component loosening. The figures for instability were 23.6%, 14.5% and 11.7%, respectively, and for periprosthetic fractures were 10.0%, 2.8%, and 3.5%. Bearing exchange was the type of revision in 40% of uncemented mobile bearing, 24.3% of cemented mobile bearing, and 5.3% cemented fixed bearing revisions. CONCLUSION: The findings of this study demonstrated improved survival with use of uncemented compared to cemented mobile bearings in medial UKA, only in those hospitals performing more than 100 cases per year. Cemented fixed bearings reported comparable survival results as uncemented mobile bearings, regardless of the annual hospital volume. The high rates of instability, periprosthetic fractures, and bearing exchange in uncemented mobile bearings emphasize the need for further research. Cite this article: Bone Joint J 2021;103-B(7):1261-1269.

Defining Minimal Clinically Important Difference After Open Hip Abductor Repair.

BACKGROUND: Open repair for gluteus medius and minimus tears is a common surgical treatment for patients with lateral hip pain associated with abductor tears; however, clinically meaningful outcomes have not been described after open surgical treatment. PURPOSE: To define the minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) in patients undergoing open gluteus medius or minimus repair, and to identify preoperative patient characteristics predictive of achieving MCID postoperatively. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective review of prospectively collected data from a consecutive series of patients undergoing open abductor repair between July 2010 and April 2019 was conducted. Perioperative patient data collected included patient characteristics and preoperative and postoperative modified Harris Hip Score (mHHS) and International Hip Outcome Tool (iHOT-33) score. Paired t tests were utilized to compare preoperative and postoperative PROMs and MCID was calculated for both PROMs. Multivariate logistical regression analysis was used to assess the association between preoperative variables and the likelihood for achieving MCID. RESULTS: A total of 47 patients were included in the study. The majority of patients were female (78.7%), with an average age of 63 ± 10.7 years. The average follow-up for both the mHHS and the iHOT-33 surveys was 37.8 ± 27.9 months (range, 10-102 months). Patients demonstrated statistically significant improvements on the mHHS and iHOT-33 postoperatively (P < .001 for both). The MCIDs of mHHS and iHOT-33 were calculated to be 9.9 and 14.3, respectively. Overall, 82.9% of patients achieved MCID for mHHS and 84.1% of patients achieved MCID for iHOT-33 postoperatively. Multivariate logistical analysis demonstrated younger patients were less likely to achieve MCID for both outcome measures. Four patients (8.5%) suffered postoperative complications after open repair. CONCLUSION: This study defined MCID for mHHS and iHOT-33 for patients undergoing open repair of hip abductor tears, with a large percentage of patients (>80%) achieving meaningful outcomes for both outcome measures. There was a low complication rate. Younger patients were less likely to achieve MCID compared with older patients.

Achievement of the minimal clinically important difference following open proximal hamstring repair.

There is a paucity of literature on patient-reported outcome measures (PROMs) following proximal hamstring repair beyond return to play, patient satisfaction and pain improvement. The minimal clinically important difference (MCID) defines the minimum degree of quantifiable improvement that a patient can perceive, but the MCID and predictors of this measure have not been defined for this patient population. This study aimed to define the MCID and determine the efficacy of open proximal hamstring repair through achievement of MCID and identify characteristics predictive of achieving MCID. A retrospective cohort review of an institutional hip registry was conducted, analyzing the modified Harris Hip Score (mHHS) and International Hip Outcome Tool (iHOT-33). MCID was calculated using a distribution-based method. Demographic and clinical variables predictive of achieving MCID were analyzed using univariable and multivariate logistic regression analyses. Thirty-nine patients who underwent open proximal hamstring repair were included. The mean patient age was 48.5 ± 12.4 years, with a mean follow-up of 37.1 ± 28 months. The MCID was determined for each PROM (mHHS-11.8; iHOT-33-12.6). A high percentage of patients achieved MCID for both PROMs (mHHS-85.7%; iHOT-33-91.4%). Univariate logistical regression demonstrated increased age (P = 0.163), increased body mass index (BMI; P = 0.072), requirement for inpatient admission (P = 0.088) and pre-operative iHOT-33 (P = 0.104) trended towards clinically significant predictors of not achieving MCID. A high percentage of patients achieved MCID while age, BMI, inpatient admission and pre-operative iHOT-33 appear to influence the achievement of clinically significant outcome in patients undergoing open proximal hamstring repair.

Characteristics of Soccer Players Undergoing Primary Hip Arthroscopy for Femoroacetabular Impingement: A Sex- and Competitive Level-Specific Analysis.

BACKGROUND: Radiographic features of femoroacetabular impingement (FAI) are prevalent in kicking athletes, especially soccer players. However, there remains a paucity of data on the characteristics of symptomatic soccer players with an established diagnosis of FAI. PURPOSE: To report on patient demographics, injury, and clinical and radiographic characteristics in a large cohort of soccer players who underwent primary hip arthroscopy for FAI and to perform a sex- and competition level-specific analysis of these data. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: An institutional hip preservation registry containing 3318 consecutive primary hip arthroscopies for FAI performed between March 2010 and January 2016 was retrospectively reviewed for patients identified as soccer players. Patient demographics, injury characteristics, and clinical and radiographic findings were recorded, and sex- and competition level-specific differences were analyzed. RESULTS: A total of 421 hips (336 soccer players) were identified, including 257 (61.0%) men and 164 (39.0%) women. Of these, 105 (24.9%) were reported as highly competitive, 194 (46.1%) as competitive, 75 (17.8%) as recreational, and 47 (11.2%) did not report a level. The majority of the 336 soccer players (231 hips; 55%) reported chronic hip pain lasting >6 months with no acute injury at the initial visit. Alpha angle, coronal center-edge angle, and femoral version on computed tomography scan measured 64.5°± 12°, 32.3°± 9°, and 13.7°± 10° (mean ± SD), respectively. There were 230 (55%) hips with a type 2 anterior inferior iliac spine (AIIS), 78 (18.5%) with a type 1 AIIS, and 19 (4.5%) with a type 3 AIIS. When compared with male athletes, female athletes had more hip internal rotation on physical examination (14.9° vs 8°; P < .001), lower alpha angles (57.5° vs 68.5°; P < .001), and lower-grade AIIS morphology (P = .003). Acute injury as the reason for hip symptoms was most likely in the highly competitive group (P < .001). CONCLUSION: Female soccer players were more likely to have less severe clinical and radiographic findings than were male soccer players. Acute injury as the cause of hip symptoms was more common in highly competitive players. CLINICAL RELEVANCE: Focusing on soccer players with an established FAI diagnosis, the findings of this study suggest that there are sex- and competition level-based differences in the presentation, physical examination, and imaging characteristics among the players. These findings can better guide clinicians in the diagnostic evaluation of symptomatic soccer players with FAI and in tailoring treatment recommendations to specific cohorts.

What is the impact of patellofemoral joint degeneration and malalignment on patient-reported outcomes after lateral unicompartmental knee arthroplasty?

AIMS: It remains controversial whether patellofemoral joint pathology is a contraindication to lateral unicompartmental knee arthroplasty (UKA). This study aimed to evaluate the effect of preoperative radiological degenerative changes and alignment on patient-reported outcome scores (PROMs) after lateral UKA. Secondarily, the influence of lateral UKA on the alignment of the patellofemoral joint was studied. METHODS: A consecutive series of patients who underwent robotic arm-assisted fixed-bearing lateral UKA with at least two-year follow-up were retrospectively reviewed. Radiological evaluation was conducted to obtain a Kellgren Lawrence (KL) grade, an Altman score, and alignment measurements for each knee. Postoperative PROMs were assessed using the Kujala (Anterior Knee Pain Scale) score, Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS JR), and satisfaction levels. RESULTS: A total of 140 knees (130 patients) were identified for analysis. At mean 4.1 years (2.0 to 8.5) follow-up, good to excellent Kujala scores were reported. The presence of mild to moderate preoperative patellofemoral joint osteoarthritis had no impact on these scores (KL grade 0 vs 1 to 3, p = 0.203; grade 0 to 1 vs 2 to 3, p = 0.674). Comparable scores were reported by patients with osteoarthritis (Altman score of ≥ 2) evident on either the medial or lateral patellofemoral joint facet (medial, p = 0.600 and lateral, p = 0.950). Patients with abnormal patellar congruence and tilt angles (≥ 17° and ≥ 14°, respectively) reported good to excellent Kujala scores. Furthermore, lateral UKA resulted in improvements to patellofemoral alignment. CONCLUSION: This is the first study demonstrating that mild to moderate preoperative radiological degenerative changes and malalignment of the patellofemoral joint are not associated with poor patient-reported outcomes at mid-term follow-up after lateral fixed-bearing UKA. Our data suggest that this may be explained by realignment of the patella and thereby redistribution of loads across the patellofemoral joint. Cite this article: Bone Joint J 2020;102-B(6):727-735.

A Comprehensive Evaluation of Lateral Unicompartmental Knee Arthroplasty Short to Mid-Term Survivorship, and the Effect of Patient and Implant Characteristics: An Analysis of Data From the Dutch Arthroplasty Register.

BACKGROUND: The rarity of lateral unicompartmental knee arthroplasty (UKA) results in a lack of large cohort studies and understanding. The aim of this study is to comprehensively evaluate survivorship of lateral UKA with registry data and compare this to medial UKA. METHODS: Lateral (n = 537) and medial UKAs (n = 19,295) in 2007-2017 were selected from the Dutch Arthroplasty Register. Survival analyses were performed with revision for any reason as primary endpoint. Adjustments were made for patient and implant characteristics. Stratified analyses according to patient and implant characteristics were performed. Reasons and type of revision were grouped according to laterality and bearing design. RESULTS: The 5-year revision rate was 12.9% for lateral UKA and 9.3% for medial UKA. Multivariable regression analyses showed no significant increased risk for revision for lateral UKA (hazard ratio 0.87, 95% confidence interval 0.66-1.15). Stratified analyses showed that the effect of patient characteristics on revision was comparable between lateral and medial UKA; however, the use of mobile-bearing design for lateral UKA was associated with increased revision rate. Progression of osteoarthritis was the main reason for revision on both sides accompanied by tibia component loosening for medial UKA. Reasons and type of revision varied depending on bearing design. CONCLUSION: Similar survivorship of lateral and medial UKA was reported. Specifically, there is a notable risk for revision when using mobile-bearing designs for lateral UKA. Failure modes and type of revision depends on laterality and bearing design. These findings emphasize that surgical challenges related to anatomy and kinematics of the lateral and medial knee compartment need to be considered.

Postoperative outcomes of total knee arthroplasty compared to unicompartmental knee arthroplasty: A matched comparison.

BACKGROUND: The purpose of this study was to evaluate early postoperative outcomes in patients following UKA (unicompartmental knee arthroplasty) compared to a matched cohort of TKA (total knee arthroplasty) patients. METHODS: Patients who met radiographic criteria for a medial UKA who underwent either a TKA or UKA at a single institution were matched based on age, gender, and BMI. RESULTS: One hundredy and fifty UKA in 138 patients and 150 TKA in 148 patients were included in this retrospective analysis. Mean age was 62.6 ±â€¯9 years and 65.2 ±â€¯9 years in the UKA and TKA groups respectively (p = .01). Patients who underwent UKA had significantly less pain at two and six weeks postoperatively compared to TKA patients with mean Numeric Pain Rating Scale (NPRS) scores of 3.7 ±â€¯1.1 vs. 7.8 ±â€¯1.2, p < .001 and 2.6 ±â€¯1.3 vs. 4.6 ±â€¯1.6, p < .001 respectively. Knee Society Scores (KSS) were higher in the UKA group at six weeks and two years postoperative (86.5 ±â€¯2.8 vs. 81.4 ±â€¯3.6, p < .001 and 89.5 ±â€¯2.4 vs. 84.5 ±â€¯3.3, p < .001 respectively). Return to work was faster in the UKA group (mean 20.6 ±â€¯7.89 vs. 38.6 ±â€¯6.23 days, p < .001). The UKA group also had higher mean Forgotten Joint Scores of 90.5 ±â€¯3.6 vs. 79.5 ±â€¯9.5 (p < .001). CONCLUSIONS: Patients with primarily medial compartment OA who underwent UKA had less postoperative pain, earlier return to work, and higher KSS compared to a matched group who underwent TKA.

Mid-term survivorship and patient-reported outcomes of robotic-arm assisted partial knee arthroplasty.

AIMS: Limited evidence is available on mid-term outcomes of robotic-arm assisted (RA) partial knee arthroplasty (PKA). Therefore, the purpose of this study was to evaluate mid-term survivorship, modes of failure, and patient-reported outcomes of RA PKA. METHODS: A retrospective review of patients who underwent RA PKA between June 2007 and August 2016 was performed. Patients received a fixed-bearing medial or lateral unicompartmental knee arthroplasty (UKA), patellofemoral arthroplasty (PFA), or bicompartmental knee arthroplasty (BiKA; PFA plus medial UKA). All patients completed a questionnaire regarding revision surgery, reoperations, and level of satisfaction. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were assessed using the KOOS for Joint Replacement Junior survey. RESULTS: Mean follow-up was 4.7 years (2.0 to 10.8). Five-year survivorship of medial UKA (n = 802), lateral UKA (n = 171), and PFA/BiKA (n = 35/10) was 97.8%, 97.7%, and 93.3%, respectively. Component loosening and progression of osteoarthritis (OA) were the most common reasons for revision. Mean KOOS scores after medial UKA, lateral UKA, and PFA/BiKA were 84.3 (SD 15.9), 85.6 (SD 14.3), and 78.2 (SD 14.2), respectively. The vast majority of the patients reported high satisfaction levels after RA PKA. Subgroup analyses suggested tibial component design, body mass index (BMI), and age affects RA PKA outcomes. Five-year survivorship was 98.4% (95% confidence interval (CI) 97.2 to 99.5) for onlay medial UKA (n = 742) and 99.1% (95% CI 97.9 to 100) for onlay medial UKA in patients with a BMI < 30 kg/m2 (n = 479). CONCLUSION: This large single-surgeon study showed high mid-term survivorship, satisfaction levels, and functional outcomes in RA UKA using metal-backed tibial onlay components. In addition, favourable results were reported in RA PFA and BiKA. Cite this article: Bone Joint J 2020;102-B(1):108-116.

The Influence of Preoperative Radiographic Patellofemoral Degenerative Changes and Malalignment on Patellofemoral-Specific Outcome Scores Following Fixed-Bearing Medial Unicompartmental Knee Arthroplasty.

BACKGROUND: There is controversy as to whether the presence of degenerative changes and malalignment of the patellofemoral joint is a contraindication to medial unicompartmental knee arthroplasty. Therefore, the aim of the present study was to examine the influence of preoperative radiographic patellofemoral joint osteoarthritis and alignment on intermediate-term knee and patellofemoral joint-specific patient-reported outcomes following fixed-bearing medial unicompartmental knee arthroplasty. METHODS: We performed a retrospective review of the records on a consecutive series of patients who had undergone robotic arm-assisted fixed-bearing onlay medial unicompartmental knee arthroplasty and had a minimum duration of follow-up of 2 years. All records were collected from a single surgeon's arthroplasty registry. Patients with severe bone loss or grooving of the lateral patellar facet were excluded. Radiographic assessment was performed with use of the Kellgren-Lawrence and Altman classification systems as well as with patellofemoral joint alignment measurements. The latest follow-up consisted of a patient-reported questionnaire, including the Kujala (Anterior Knee Pain Scale) score, the Knee Injury and Osteoarthritis Outcome Score (KOOS), Junior (JR), and satisfaction levels. RESULTS: A total of 536 patients (639 knees) were included. After a mean duration of follow-up (and standard deviation) of 4.3 ± 1.6 years (range, 2.0 to 9.2 years), good-to-excellent Kujala scores were reported independent of the presence of patellofemoral joint osteoarthritis preoperatively (Kellgren-Lawrence grade 0 compared with ≥1, p = 0.82; grade ≤1 compared with ≥2, p = 0.84). Similar findings were found when osteoarthritis was present in either the medial or lateral side of the patellofemoral joint as defined by an Altman score of ≥2 (medial, p = 0.81; lateral, p = 0.90). KOOS scores and satisfaction also were not affected by degenerative patellofemoral joint changes. Furthermore, neither the patellar tilt angle nor the congruence angle influenced patient-reported outcomes. CONCLUSIONS: Preoperative radiographic mild to moderate patellofemoral joint degeneration (Kellgren-Lawrence grades 1 through 3) and/or malalignment did not compromise intermediate-term knee and patellofemoral joint-specific patient-reported outcomes in patients managed with fixed-bearing medial unicompartmental knee arthroplasty. On the basis of the results of the present study, we believe that neither mild to moderate patellofemoral degeneration nor abnormal patellar tilt or congruence should be considered a contraindication to fixed-bearing medial unicompartmental knee arthroplasty. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Bearing design influences short- to mid-term survivorship, but not functional outcomes following lateral unicompartmental knee arthroplasty: a systematic review.

PURPOSE: To determine survivorship and functional outcomes of fixed and mobile-bearing designs in lateral unicompartmental knee arthroplasties (UKA). METHODS: Medline, EMBASE and Cochrane databases were searched. Annual revision rate and functional outcomes were assessed for both fixed and mobile-bearing designs. RESULTS: A total of 28 studies, of which 19 fixed-bearing and 9 mobile-bearing, representing 2265 lateral UKAs were included for survivorship and functional outcome analyses. The mean follow-up of fixed and mobile-bearing studies was 7.5 and 3.9 years, respectively. Annual revision rate of fixed-bearing designs was 0.94 (95% CI 0.66-1.33) compared to 2.16 (95% CI 1.54-3.04) for mobile-bearing. A subgroup analysis of the domed shaped mobile-bearing design noted an annual revision rate of 1.81 (95% CI 0.98-3.34). Good-to-excellent functional outcomes were observed following fixed and mobile-bearing lateral UKAs; no significant differences were found. CONCLUSION: Mobile-bearing lateral UKAs have a higher rate of revision compared to fixed-bearing lateral UKAs with regard to short- to mid-term survivorship; however, the clinical outcomes are similar. Despite the introduction of the domed shaped mobile-bearing design, findings of this study suggest fixed-bearing implant design is preferable in the setting of isolated lateral osteoarthritis (OA). This systematic review was based on low to moderate evidence, therefore, future registry data are needed to confirm these findings. However, this study included a large number of patients, and could provide information regarding risk of revision and functional outcomes of mobile and fixed-bearing type lateral UKA. LEVEL OF EVIDENCE: IV.