Abstract. High tibial osteotomy (HTO) is a well-recognised procedure to address medial compartment osteoarthritis (OA). There remains dispute on the impact of pre-operative patient factors on patient related outcome measures (PROMS). Does BMI and age affect > 2 year and > 5 year oxford knee scores (OKS) and Knee injury and osteoarthritis outcome scores (KOOS). A retrospective review of a prospectively collected database was performed. Timeframe was 26/6/2014 and 25/8/2022. BMI and age were recorded. OKS and KOOS were collected at > 2 years and > 5 years. There were 81 procedures included, of these 50 had OKS and KOOS scores at > 2 years and 35 at > 5 years. Median BMI was 28.5kg/m. 2. , range was 18.6–40.8kg/m. 2. Spearman's rank for >2 year OKS was p(df)=−0.210 p=0.157, > 5 year OKS p(df)=−0.215 p=0.230. For > 2 year and > 5 year KOOS subscales there were no statistically significant associations on Spearman's rank. For age, median age was 52.5, range 26–71 years old. OKS at >2 year p(df)=0.068 p=0.664, OKS >5 years p(df)=0.065 p= 0.709. For >2 year and > 5 year KOOS subscales there were no statistically significant associations on Spearman's rank. There were no adverse outcome in patients up-to the age of 71. There were no statistically significant Spearman's rank correlations between PROMS and OKS/KOOS scores. This supports recent KOG consensus statement highlighting physiological age importance vs chronological age. Of note there were more negative associations in the BMI group compared with age

Aims. The primary aim of the study was to perform an analysis to identify the cost per quality-adjusted life-year (QALY) of robot-assisted unicompartmental knee arthroplasty (rUKA) relative to manual total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) for patients with isolated medial compartment osteoarthritis (OA) of the knee. Secondary aims were to assess how case volume and length of hospital stay influenced the relative cost per QALY. Patients and Methods. A Markov decision analysis was performed, using known parameters for costs, outcomes, implant survival, and mortality, to assess the cost-effectiveness of rUKA relative to manual TKA and UKA for patients with isolated medial compartment OA of the knee with a mean age of 65 years. The influence of case volume and shorter hospital stay were assessed. Results. Using a model with an annual case volume of 100 patients, the cost per QALY of rUKA was £1395 and £1170 relative to TKA and UKA, respectively. The cost per QALY was influenced by case volume: a low-volume centre performing ten cases per year would achieve a cost per QALY of £7170 and £8604 relative to TKA and UKA. For a high-volume centre performing 200 rUKAs per year with a mean two-day length of stay, the cost per QALY would be £648; if performed as day-cases, the cost would be reduced to £364 relative to TKA. For a high-volume centre performing 200 rUKAs per year with a shorter length of stay of one day relative to manual UKA, the cost per QALY would be £574. Conclusion . rUKA is a cost-effective alternative to manual TKA and UKA for patients with isolated medial compartment OA of the knee. The cost per QALY of rUKA decreased with reducing length of hospital stay and with increasing case volume, compared with TKA and UKA. Cite this article: Bone Joint J 2019;101-B:1063–1070

Summary. This study shows a significant reduction in knee adduction moment in patients with medial compartment osteoarthritis, in both the symptomatic and asymptomatic knees. Long-term follow-up studies are required to confirm the effect of treating the asymptomatic side on disease progression. Background. The knee is the commonest joint to be affected by osteoarthritis, with the medial compartment commonly affected. Knee osteoarthritis is commonly bilateral, yet symptoms may initially present unilaterally. Higher knee adduction moment has been associated with the development and progression of medial compartment knee osteoarthritis. The aim of this study was to assess the effect of lateral wedge insoles on the asymptomatic knee of patients with unilateral symptoms of medial compartment knee osteoarthritis. Methods. Twenty patients were assessed using a 3D optoelectronic tracking system, with 16 infrared camera, passive markers and four force platforms. Three different insoles were tested; a standard control shoe, the Boston lateral wedge insole (inclined at 5° throughout the full length of the insole) and the Salford insole (inclined at 5° throughout the full length of the insole, with medial arch support). A minimum of 5 trials per each insole were used. Kinetic and kinematic data were collected and processed using Qualysis Track Manager ® and Visual 3D™. Results. There was a significant reduction in knee adduction moment for both the Salford and Boston insoles as compared to the control shoe. This was 9.5–14.2% for the asymptomatic side, and 5.8–10.7% for the symptomatic side for the Salford and Boston insoles respectively. Although the reduction was larger on the asymptomatic side, this was not statistically significant. Patients reported significant reduction in pain with both Salford and Boston insoles as compared to the control shoe, and found the Salford insole to be the most comfortable. Stride length and walking speed was significantly higher with the Salford insole. Conclusions. This study confirms the effect of lateral wedge insoles on reducing knee adduction moment in patients with medial compartment osteoarthritis, in both the symptomatic and asymptomatic knees. Long-term follow-up studies are required to confirm the effect of treating the asymptomatic side on disease progression

A majority of patients present with varus alignment and predominantly medial compartment disease. The secret of success in osteoarthritis (OA) treatment is patient selection and patient specific treatment. Different wear patterns have been described and that knowledge should be utilised in modern knee surgery. In case of isolated anteromedial OA, unicompartmental knee arthroplasty (UKA) should be one of the therapeutic options available to the knee surgeon. The discussion not to offer a UKA to patients is based on the fear of the surgeon not being able to identify the right patient and not being able to perform the surgery accurately. The common modes of failure for UKA, which are dislocation or overcorrection leading to disease progression, can be avoided with a fixed bearing implant. Wear can probably be avoided with newer polyethylenes and avoidance of overstuffing in flexion of the knee. Revision for unexplained pain and unknown causes should disappear once surgeons understand persistent pain after surgery much better than they do today. The choice in favor of UKA is a choice of function over survivorship, a choice for reduced comorbidity and lower mortality. Many of the common problems in TKA are not an issue in UKA. Component overhang, decreased posterior offset, changed joint line height, gap mismatch, flexion gap instability, lift off and paradoxical motion hardly exist in UKA if the replacement is performed according to resurfacing principles with respect for the native knee anatomy. New technologies like navigation, PSI and robotics will help with alignment and component positioning. Surgeon education and training should allow over time UKA to be performed by all of us

Introduction: We present preliminary short term results of medial opening wedge high tibial osteotomy with hemicallotasis using a monolateral external fixator, combined with microfracturing, in younger active patients with established Grade IV medial compartment osteoarthritis. Methods: Prospectively collected data was analysed for 28 consecutive knees in 27 patients undergoing this procedure. Mean age was 47 years (range 28 to 64), follow up was 23 months (range 7 to 61). Results: Mean Lysholm scores improved from 63.6 before surgery (range 42 to 85) to 81.6 at latest follow-up (range 46.5–100) (p< 0.001). Similarly, the mean Tegner activity scale improved from 1.7 (range 1 – 4) to 3.3 (range 1 – 6) (p< 0.001). Average IKDC score at last follow-up was 68 (range 35.6 – 100). Mean pain score (visual analogue scale 0 to 10) improved from 5.5 pre-operatively (range 1 – 9), to 3.5 at latest follow-up (range 0 – 8) (p< 0.001). All but 4 patients reported improved pain scores. Superficial pin site infection occurred in 6 patients (21.4%) and settled with oral antiobiotics in all cases. One patient had persistent patellofemoral (PF) pain. Discussion: The use of hemicallotasis for high tibial osteotomy (HTO) in association with extensive microfracturing of the medial compartment provides a viable, minimally invasive method for management of the young active patient with medial compartment osteoarthritis, without the risk of serious complications. In the short term even with advanced full thickness cartilage damage, this provides effective pain relief, helps put off more major arthroplasty alternatives and improves activity levels

Introduction: We present preliminary short term results of medial opening wedge high tibial osteotomy with hemicallotasis using a monolateral external fixator, combined with microfracturing, in younger active patients with established Grade IV medial compartment osteoarthritis. Methods: Prospectively collected data was analysed for 28 consecutive knees in 27 patients undergoing this procedure. Mean age was 47 years (range 28 to 64); follow up was 23 months (range 7 to 61). Results: Mean Lysholm scores improved from 63.6 before surgery (range 42 to 85) to 81.6 at latest follow-up (range 46.5–100) (p< 0.001). Similarly, the mean Tegner activity scale improved from 1.7 (range 1–4) to 3.3 (range 1–6) (p< 0.001). Average IKDC score at last follow-up was 68 (range 35.6–100). Mean pain score (visual analogue scale 0 to 10) improved from 5.5 pre-operatively (range 1–9), to 3.5 at latest follow-up (range 0–8) (p< 0.001). All but 4 patients reported improved pain scores, one of whom had patellofemoral pain. Superficial pin site infection occurred in 6 patients (21.4%) and settled with oral antibiotics in all cases. Discussion: The use of hemicallotasis for high tibial osteotomy in association with extensive microfracturing of medial compartment provides a viable, minimally invasive method for management of the young active patient with medial compartment osteoarthritis, without the risk of serious complications. In the short term even with advanced full thickness damage, this provides effective pain relief, helps put off more major arthroplasty alternatives and allows patients an improved activity level. The external fixator provides a very stable functional stabilization, superior to other available methods of internal fixation

For medial compartment disease UKR has many advantages over TKR. They give better function, faster recovery, lower morbidity and mortality but have a higher revision rate. Matched studies from the England and Wales National Joint Registry showed they are 60% more likely to achieve excellent outcomes (OKS>41) and 30% more likely to have excellent satisfaction. UKR patients were discharged 1.4 days earlier, had 35% less readmissions and 50% less major complications such as DVT/PE, infection, CVA and MI. The death rate was significantly lower: The hazard ratios being 0.2x at 30 days, 0.5x at 90 days and 0.85x at 8 years. However at 8 years the revision rate was 2x higher and the reoperation rate was 1.4x. If 100 patients receiving TKR had UKR instead, the result would be around one fewer death and three more reoperations in the first 4 years. If patients were aware of this most would select a UKR. The main reason why UKR have a high revision rate in registries is that most surgeons do small numbers and restrict their use to patients with very early disease, who often do badly. In the NJR 8% of knees are UKR and surgeons do on average 5 per year. Surgeons doing more than 20% of knees as UKR have a much lower re-operation rate which is similar to that of TKR. The Mobile bearing UKR can safely be used in up to 50% allowing many patients to have the advantages of UKR and a low re-operation rate

The role of unicompartmental knee arthroplasty (UKA) in spontaneous osteonecrosis of the knee (SONK) remains controversial, even though SONK usually involves only medial compartment of the knee joint. We aimed to compare the survival rate and clinical outcomes of UKA in SONK and medial compartment osteoarthritis (MOA) via a meta-analysis of previous studies. MEDLINE database in PubMed, the Embase database, and the Cochrane Library were searched up to January 2018 with keywords related to SONK and UKA. Studies were selected with predetermined inclusion criteria: (1) medial UKA as the primary procedure, (2) reporting implant survival or clinical outcomes of osteonecrosis and osteoarthritis, and (3) follow-up period greater than 1 year. Quality assessment was performed using the risk of bias assessment tool for non-randomised studies (RoBANs). A random effects model was used to estimate the pooled relative risk (RR) and standardised mean difference. The incidence of UKA revision for any reason was significantly higher in SONK than in MOA group (pooled RR = 1.83, p = 0.009). However, the risk of revision due to aseptic loosening and all- cause re-operation was not significantly different between the groups. Moreover, when stratified by the study quality, high quality studies showed similar risk of overall revision in SONK and MOA (p = 0.71). Subgroup analysis revealed worse survival of SONK, mainly related to high failure after uncemented UKA. Clinical outcomes after UKA were similar between SONK and MOA (p = 0.66). Cemented UKA has similar survival and clinical outcomes in SONK and MOA. Prospective studies designed specifically to compare the UKA outcomes in SONK and MOA are necessary

Introduction: The aim of this study was to determine the outcome of Tomofix plate fixation, in joint retaining surgery, for Medial compartment Osteoarthritis of the knee in young patients. Methods: We report on 33 patients (36 knees) who underwent High tibial osteotomy for unicompartmental osteoarthritis of the knee. The mean age was 39.5 (30–49). There were 20 males and 13 female. All the patients had Medial opening-wedge type Osteotomy using the Tomofix device. The mean duration of follow-up was 48 months (44–60 months). The patients were assessed on the basis of pre and post-operative oxford knee score, knee range of motion, radiological evidence of healing of the osteotomy site and alignment of the knee. Results: There were no nonunions at the osteotomy site and the medial open-wedge filled-in without any need for bone graft or its substitutes. The mean preoperative oxford knee score was 48 (S.D 4.7 Range 38–54). This improved to a mean score of 22 (S.D 5.9 Range 17–31) after 1 year follow-up. The improvement was significant (pvalue= 0.07). The preoperative average knee flexion was 103.1 (S.D 25.2 Range 10–125) which improved after 1 year follow up to 112 (S.D 15.9 Range 0–140). The mean preoperative Femorotibial angle was 10 degrees varus (range 9–15). The mean postoperative Femorotibial angle was 8 deg valgus (range 6–12). Radiologically, there was no loss of correction during our follow-up. One patient had post-operative DVT. Conclusion: Our study shows that Tomofix plate fixation in High Tibial osteotomy gives immediate stability, good deformity correction and allows early rehabilitation. The osteotomy gap does not require bone grafting and the correction is maintained. The Short term functional results are encouraging. Longer-term follow-up is however needed to establish its effectiveness in deferring joint replacement surgery in young patients

The aim of this study was to examine the functional outcome at ten years following lateral closing wedge high tibial osteotomy for medial compartment osteoarthritis of the knee and to define pre-operative predictors of survival and determinants of functional outcome. . 164 consecutive patients underwent high tibial osteotomy between 2000 and 2002. A total of 100 patients (100 knees) met the inclusion criteria and 95 were available for review at ten years. Data were collected prospectively and included patient demographics, surgical details, long leg alignment radiographs, Western Ontario and McMaster Universities osteoarthritis index (WOMAC) and Knee Society scores (KSS) pre-operatively and at five and ten years follow-up. At ten years, 21 patients had been revised at a mean of five years. Overall Kaplan–Meier survival was 87% (95% confidence interval (CI) 81 to 94) and 79% (95% CI 71 to 87) at five and ten years, respectively. When compared with unrevised patients, those who had been revised had significantly lower mean pre-operative WOMAC Scores (47 (21 to 85) vs 65 (32 to 99), p < 0.001), higher mean age (54 yrs (42 to 61) vs 49 yrs (26 to 66), p = 0.006) and a higher mean BMI (30.2; 25 to 39 vs 27.9; 21 to 36, p = 0.005). Each were found to be risk factors for revision, with hazard ratios of 10.7 (95% CI 4 to 28.6; pre-operative WOMAC < 45), 6.5 (95% CI 2.4 to 17.7; age > 55) and 3.0 (95%CI 1.2 to 7.6; BMI > 30). Survival of patients with pre-operative WOMAC > 45, age < 55 and BMI < 30 was 97% at five and ten years. WOMAC and KSS in surviving patients improved significantly between pre-operative (mean 61; 32 to 99) and five (mean 88; 35 to 100, p = 0.001) and ten years (mean 84; 38 to 100, p = 0.001). Older patients had better functional outcomes overall, despite their higher revision rate. This study has shown that improved survival is associated with age < 55 years, pre-operative WOMAC scores > 45 and, a BMI < 30. In patients over 55 years of age with adequate pre-operative functional scores, survival can be good and functional outcomes can be significantly better than their younger counterparts. We recommend the routine use of pre-operative functional outcome scores to guide decision-making when considering suitability for high tibial osteotomy. Cite this article: Bone Joint J 2014;96-B:1491–7

Several attempts have been made to treat medial compartment OA of the knee with mobile spacers. All have met with dismal failure. This presentation explores the history of attempts to treat OA in the younger knee with mobile spacers and explains why they were all doomed to fail. Sources of information for this presentation include the published peer reviewed literature, publically available documents, and an insiders view of some of the failed attempts to solve the problem of medial compartment OA with mobile spacers. All attempts to treat medial compartment OA of the knee with mobile spacers have failed. The unispacer has been a failure with a 60% revision rate at three years. The ABS intercushion had a 100% revision rate at one year and in many cases caused permanent damage to the host knees. The Salucartilage spacer was implanted in one patient only and failed within 48 hours. Mobile spacers do not work, are never likely to work, and are not indicated for the treatment of medial compartment osteoarthritis of the knee

This observational study was undertaken to explore the relationship of the foot posture of patients with Medial Compartment Osteoarthritis of the knee (MCOA), patients with hip osteoarthritis (OA) and a healthy control group, using the Foot Posture Index (FPI). Goniometric measurement of talocrural dorsiflexion was also included. The relationship of foot posture to MCOA and hip osteoarthritis OA has not been explored although in other medical fields, such as neurology and sports medicine, the relationship between foot posture, lower limb pain and function has been acknowledged. In view of the current high incidence of lower limb OA, any investigation of associations that may lead to improved assessment and conservative management is worthy of consideration. Currently, systematic examination of the foot is not undertaken in routine clinical assessment of patients with lower limb OA and, if this were to be introduced, there would be difficulty in selecting suitable clinical outcome measures. The recent development of the Foot Posture Index (FPI) has addressed the need for a diagnostic clinical tool that measures foot posture in multiple planes and anatomical segments. Sixty participants took part: twenty patients with radiographic and clinical evidence of MCOA grade IV, twenty patients with radiographic and clinical evidence of stage IV OA hip, and twenty age-matched healthy volunteers as a control group. A one way Analysis of variance (ANOVA) was performed to investigate any differences between the 3 groups for foot posture using FPI scores and talocrural dorsiflexion measurements. This showed that there were significant differences between the groups (p< 0.001). Patients with MCOA had a high positive FPI score (indicating a pronated foot), patients with hip OA had a low negative FPI score (indicating a supinated foot). The healthy controls had a normal score distributed over a wider range than the other two groups. In addition, the results of the Pearsons test indicate that the FPI correlated positively with talocrural dorsiflexion (r = 0.55, p< .001). Differences in foot characteristics may be influenced by specific treatment modalities such as gait reducation, orthotic provision, specific lower limb strengthening and stretching exercises. Foot assessment might therefore be a useful adjunct to conservative management of both MCOA and hip osteoarthritis

The outcome of arthroscopic medial release of 255 knees in 173 patients for varying grades of osteoarthritis involving the medial compartment is reported. All operations were performed by a single surgeon between January 2001 and May 2003. The Knee Society score for pain and the patient’s subjective satisfaction were used for the outcome evaluation. Overall, satisfactory outcome was reported for 197 knees (77.3%) and the mean Knee Society score for pain improved from 17.6 (95% confidence interval, 16.7 to 18.5), pre-operatively to 39.4 (95% confidence interval, 37.9 to 41.1) (p < 0.001). There were minor manageable complications of persistent effusion in 16 knees and prolonged wound discomfort in 11. In total, 15 of the 21 knees with poor results were converted to total knee replacements and two other patients (three knees) were offered this option after a mean period of 16 months.

Based on these observations arthroscopic medial release is an effective treatment for osteoarthritis of the medial compartment of the knee joint and can be expected to reduce the pain in the majority of patients for at least four years post-operatively.

Introduction: The treatment of isolated medial compartment osteoarthritis (OA) in the young or physically active patient is a challenging problem for the orthopaedic surgeon. The rationale for high tibial osteotomy (HTO) in medial compartment OA with varus deformity is to correct varus malalignment and to redistribute load to the non-diseased lateral compartment of the knee. Here we present our early to mid-term clinical and radiological findings. Methods: Between October 2005 and April 2007 9 patients underwent HTO and TSF application. Pre-operative OA grade was recorded using the Ahlbäck classification. Radiographs were used to calculate the pre and post operative measurements for the tibiofemoral angle, the mechanical axis deviation and the tibial slope. Correction planning was carried out using the Spatialframe software package. All operations were performed by a single experienced consultant orthopaedic surgeon specialising in Ilizarov and limb reconstruction surgery. Pre and post-operative Oxford knee scores were collected for each patient. Results: Median follow-up was 19 months (range 15–35). Median age at operation was 49 years (range 37–59). On preoperative radiographic examination eight knees were Ahlbäck grade 1 and one knee was Ahlbäck grade 2. The median time spent in the frame was 18 weeks (range 12–37). The median total angle of correction according to correction program given was 14 degrees (range 10–22) and the median duration of correction was 18 days (range 14–36) with 6 patients requiring an additional correction program. 2 patients subsequently underwent matrix induced autologous chondrocyte implant (MACI) for osteochondral defects. In the primary OA group we found an improvement in mean Oxford knee score after HTO from 28.3 to 37.8/48 post-operatively. 1 patient was non-compliant with the correction and required a total knee replacement (TKR) for continued pain at 36 weeks post frame removal. 1 patient required fibular osteotomy during their correction. 6 (67%) of the 9 patients had a documented pin site infection. The median Otterburn grade was 3 (range 0–4). There were no cases of chronic bone infection. Conclusions: High tibial osteotomy performed with the Taylor spatial frame presents a viable treatment option in active patients with early medial compartment OA. With TKR as an end point the survival rate of HTO for treatment of OA was 88.9% at a median of 19 months follow-up. Our results also indicate successful use of the technique in combination with MACI

There exists a variety of options for a medial compartment knee with osteoarthritis, specifically a unicompartmental knee, high tibial osteotomy, and total knee arthroplasty. This surgeon prefers a rotating platform posterior stabilised total knee to the unicompartmental knee. Unicompartmental knee arthroplasty (UKA) in younger patients is being performed with increasing frequency. While UKA is a powerful marketing tool because of its minimally invasive nature and quality of knee function that is superior to the total knee arthroplasty (TKA), it has tremendous drawbacks. These include: the selection criteria is very specific and the number of patients that fit in that category is small, there is a steep learning curve for the surgeon to perfect the technique, higher failure due to wear and loss of fixation, and unexplained pain. Based on level 1 and 2 evidence available it is not justified to do more UKAs at present when the results of a TKA are so successful.

High tibial osteotomy (HTO) is a common procedure for treating medial compartment knee arthritis. The main goal is to reduce knee pain by transferring weight-bearing loads to the relatively unaffected lateral compartment and thus delaying the need of total knee replacement (TKR) by slowing or stopping destruction of medial compartment.

Between 2002 and 2010, 34 HTO's were carried out in 32 patients (Mean age 44.2). Results were reviewed in 23 patients with an average follow-up of 10.2 years (range 6–14 years). Oxford knee score (OKS) assessment was carried out on those patients. Of the remaining 11 patients, one was excluded, 2 were lost to follow-up, and 2 had died. Five cases had TKR at an average 8.8 years since having HTO.

OKS results revealed nine cases (39.1percnt;) scored (40–48) which indicate satisfactory joint function and don't require treatment. Three cases (13percnt;) scored (30–39) indicating mild to moderate arthritis. Six cases (26.1percnt;), scored (20–29) indicating moderate to severe arthritis. Five cases (21.8percnt;) scored (0–19) indicating severe arthritis.

Only five patients (14.7percnt;) had TKR (6–14) years after there HTO. The majority of cases had an OKS suggesting satisfactory joint function. Even those with scores suggesting moderate to severe arthritis were able to function normally for more than 6 years.

The successful outcome of HTO can be maintained for more than 6–16 years. We conclude that HTO should be recommended for the treatment of medial compartment arthritis of the knee in young and active patients for symptomatic improvement and maintenance of activity levels.

While no one would argue the necessary role for the medical management of patients with early knee arthritis, significant controversy remains regarding the ideal treatment for a patient with bone-on-bone osteoarthritis who could equally be treated with a high tibial osteotomy, a uni-compartmental total knee, potentially a patello-femoral replacement if dealing with isolated patello-femoral disease or lastly, a complete total knee replacement. While clearly to date there has not been consensus on this issue, a review of the arguments, both pro and con, should be used as a guide to the surgeon in making this clinical judgment.

Patient Satisfaction - Many ardent supporters of uni-compartmental knee replacements espouse one of the principle benefits of the uni knee as much greater patient satisfaction. Unfortunately, what is never taken into account is the pre-selection bias that occurs in this patient population. Patients with the most minimal amount of arthritis and those with the greatest range of motion are pre-selected to undergo a uni-compartmental knee replacement compared to the more advanced arthritic knee with malalignment and more significant preoperative disability that will undergo a total knee replacement. Additionally the sources of data to draw the conclusions must be carefully analyzed. We must avoid using data from small series with unblinded patients performed by surgeons expert in the technique. Instead registry data, with its broad based applicability, is a much more logical source of information. Of significance, when over 27,000 patients were assessed regarding satisfaction following knee surgery; there was no difference in proportions of satisfied patients whether they had a total knee or a uni-compartmental knee.

Implant Longevity - Once again large prospective cohort data in the form of arthroplasty registries strongly favors total knee arthroplasty over uni-compartmental knee arthroplasty. The Swedish Knee Arthroplasty Registry demonstrated higher revision rates with uni's as compared with total knee replacements. In the Australian Joint Replacement Registry the cumulative 13-year percent revision rate for primary total knee replacements is 6.8% and for uni-compartmental knee replacements is 15.5%. Higher failure rates in uni-compartmental knee replacements seen in Australia has correlated to a significant decrease in the number of uni's being performed, which peaked at 15.1% in 2003 and in 2014 has reduced to 4.7%. There is a direct correlation to age, with younger patients having a significantly higher percentage of revision following uni-compartmental knee replacements (25% failure rate at 11 years if less than 55 years old). There is also tremendous variability in the success rate of the uni in the Australian Registry depending on the implant design (5-year cumulative revision rate range 5.0% to 18.9%), which is simply not seen in the total knee replacement population (5-year cumulative revision rate range 1.6% to 7.7%).

While one can perform the philosophical exercise of debating the merits of a total knee versus uni-compartmental knee, the evidence is overwhelming that in the hands of the masses a total knee replacement patient will have equal satisfaction to a uni-compartmental patient, and will enjoy a much lower probability of revision in the short term and in the long term.

Limited literature exists providing comprehensive assessment of complications following opening wedge high tibial osteotomy (OWHTO). We performed a retrospective study of local patients who underwent OWHTO for isolated medial compartment knee osteoarthritis from 1997–2013.

One hundred and fifteen patients met inclusion criteria. Mean follow-up = 8.4years. Mean age = 47 (range 32–62). Mean BMI = 29.1 (range 20.3–40.2). Implants used included Tomofix (72%), Puddu plate (21%) and Orthofix (7%) (no significant differences in age/ sex/ BMI). Wedge defects were filled with autologous graft (30%), Chronos (35%) or left empty (35%).

Five year survival rate (conversion to arthroplasty) = 80%. Overall complication rate = 31%. 25% of patients suffered 36 complications including minor wound infections (9.6%), major wound infections (3.5%), metalwork irritation necessitating plate removal (7%), non-union requiring revision (4.3%), vascular injury (1.7%), compartment syndrome (0.9%), and other minor complications (4%). No thromboembolic complications were observed.

A higher BMI (mean 34.2) was apparent in those patients suffering complications than those not (mean 26.9). No significant differences existed in complication rates relative to implant type, type of bone graft used or patient age at surgery.

Complications following OWHTO appear higher than previously reported in the literature; serious complications appear rare.

We aimed to analyse complication rates following medial opening-wedge high tibial osteotomy (OWHTO) for knee OA.

A regional retrospective cohort study of all patients who underwent HTO for isolated medial compartment knee OA from 2003–2013.

115 OWHTO were performed. Mean age = 47 (95%CI 46–48). Mean BMI = 29.1 (95%CI 28.1–30.1).

Implants used: 72% (n=83) Tomofix, 21% (n=24) Puddu plate, 7% (n=8) Orthofix Grafts used: 30% (n=35) autologous, 35% (n=40) artificial and 35% (n=40) no graft. 25% (n=29) of patients suffered 36 complications. Complications included minor wound infection 9.6%, major wound infection 3.5%, metalwork irritation necessitating plate removal 7%, non-union requiring revision 4.3%, vascular injury 1.7%, compartment syndrome 0.9%, and other minor complications 4%.

Apparent higher rates of non-union occurred with the Puddu plate (8.3%) relative to Tomofix (3.6%) but was not statistically significant. No other significant differences existed in complication rates relative to implant type, bone graft used, patient age or BMI.

Serious complications following HTO appear rare. The Tomofix has an apparent lower rate of non-union compared to older implants but greater numbers are required to determine significance. There is no significant difference in union rate relative to whether autologous graft, artificial graft or no graft is used.

The aim of this study was to assess the value of plain AP and lateral radiographs in determining ACL condition in medial unicompartmental osteoarthritis.

Background: A functioning ACL has been shown to be important in the success of certain unicompartmental knee replacements. White (2001) has shown MRI to be too sensitive in this age group of patients. Keyes (1992) suggested that stress radiographs were necessary to accurately assess ACL integrity.

Method: One hundred and twenty-six patients undergoing knee arthroplasty for medial osteoarthritis, had their ACL’s graded as Normal, Frayed or Absent intra-operatively. Standard pre-operative AP and lateral standing radiographs were graded by the Ahlback system. On the lateral view, the plateau was divided into 5 zones from anterior to posterior. The zone, in which the point of deepest wear occurred, was recorded.

Results: There was a significant difference between the occurrence of deepest wear in the anterior three zones versus the posterior two zones for ACL normal and absent knees (² = 46.85, P< 0.001). There was a significant difference between the occurrence of normal and absent ACL’s in Ahlback grades ≤3 versus ≥4 (² = 53.8, P< 0.001). There was a moderately strong correlation between both zone of deepest wear on lateral radiograph and Ahlback grade with ACL condition (Spearman’s rho = 0.62 and 0.69 respectively). The Positive Predictive Values for the ACL being normal are 64% for Ahlback grades 3 or less and 67% for Zone of deepest wear in the anterior 3 zones. The Positive Predictive Values for the ACL being intact (but not necessarily normal) are 95% for Ahlback grade 3 or less; 91% for Zone of deepest wear in the anterior 3 zones; and 97% if these criteria are combined.

Combining Ahlback grade ≤3 with wear in the anterior 3 zones also gave a Negative Predictive Value of 92% for the ACL not being normal.

Conclusion: There is a “watershed” in ACL condition between Ahlback grade 3 and 4. Prostheses requiring Normal or Intact ACL’s should only be performed if Ahlback grade is ≤3. Standard radiographs can reliably predict ACL condition with high Positive and Negative predictive values.