Accelerated recovery for unicompartmental knee replacement--a feasibility study

The effect of pregabalin on postoperative pain after anterior cruciate ligament reconstruction: A systematic review of randomized clinical trials

Background

Despite the enormous success of anterior cruciate ligament (ACL) reconstruction, acute neuropathic pain can develop postoperatively and is both distressing and difficult to treat once established. Pregabalin, an anticonvulsant agent that selectively affects the nociceptive process, has been used as a pain relief agent. The purpose of this systematic review of randomized controlled trials (RCTs) was to evaluate the pain control effect of pregabalin versus placebo after ACL reconstruction.

Method

A search of the literature was performed from inception to June 2022, using PubMed, Scopus, Google Scholar, Web of Science, Cochrane and EBSCO. Studies considered for inclusion were RCTs that reported relevant outcomes (postoperative pain scores, cumulative opioid consumption, adverse events) following administration of pregabalin in patients undergoing ACL reconstruction.

Result

Five placebo-controlled RCTs involving 272 participants met the inclusion criteria. 75 mg and 150 mg oral pregabalin was used in included trials. Two studies used a single dose of pregabalin one hour before anesthesia induction. Two studies used pregabalin 1 hour before anesthesia induction and 12 hours after. One study used daily pregabalin 7 days before and 7 days after surgery. Out of five papers, three papers found significantly lower pain intensity and cumulative opioid consumption in pregabalin group compared with placebo group. However, a decrease in pain scores was found in all trials. Pregabalin administration was associated with dizziness and nausea.

Conclusion

The use of pregabalin may be a valuable asset in pain management after ACL reconstruction. However, future studies with larger sample size and longer follow-up period are required.

Early post-operative physiotherapy rehabilitation after primary unilateral unicompartmental knee replacement: a systematic review

BACKGROUND

Unicompartmental Knee Replacement (UKR) is an established treatment for end stage arthritis affecting one compartment of the knee. UKR lends itself to rapid recovery and early discharge. The content, type, timing and dose of early post-operative physiotherapy treatment has yet to be reviewed.

OBJECTIVE

To review the content of early physiotherapy in the first eight weeks following unilateral UKR.

DATA SOURCES

A literature search of Medline, CINAHL, AMED and PubMed and the Physiotherapy Evidence Database (PEDRo) plus citation searching.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) and observational studies reporting a physiotherapy intervention for UKR involving a form of post-operative exercise/education/advice delivered within the first eight weeks of surgery and commencing as an in-patient. Two reviewers independently performed screening, data extraction and risk of bias assessment.

DATA SYNTHESIS

Narrative syntheses were undertaken due to the heterogeneity of the primary outcomes.

RESULTS

Eleven studies were included (n = 1293 participants), three RCTs and eight observational studies. The dose and content of post-operative physiotherapy was highly variable with a move in recent years to rapid recovery and same day discharge with more self-directed rehabilitation. No studies had a low risk of bias.

LIMITATIONS

Small sample sizes and high heterogeneity limit our findings CONCLUSIONS: This review highlights the range of post-operative physiotherapy provision following UKR with a recent move to minimal physiotherapy input. Further research is required to identify those patients who may need additional physiotherapy above that now routinely provided, along with the most effective timing, type, and dosage of the intervention.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42021243238. CONTRIBUTION OF THE PAPER.

Fewer Adverse Events Following Outpatient Compared with Inpatient Unicompartmental Knee Arthroplasty

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is a common procedure for unicompartmental knee arthritis, often resulting in pain relief and improved function. The demand for total knee arthroplasty in the U.S. is projected to grow 85% between 2014 and 2030, and the volume of UKA procedures is growing 3 to 6 times faster than that of total knee arthroplasty. The purpose of the present study was to examine the safety of outpatient and inpatient UKA and to investigate changes over time as outpatient procedures were performed more frequently.

METHODS

Patients who underwent UKA from 2005 to 2018 as part of the National Surgical Quality Improvement Program were identified. Patients were divided into an early cohort (5,555 patients from 2005 to 2015) and late cohort (5,627 patients from 2016 to 2018). Outpatient status was defined as discharge on the day of surgery. Adverse events within 30 days postoperatively were compared, with adjustment for baseline characteristics with use of standard multivariate regression and propensity-score-matching techniques.

RESULTS

Among the 5,555 cases in the early cohort, the rate of surgical-site infection was lower for inpatient (0.84%) compared with outpatient UKA (1.69%; adjusted relative risk [RR] for inpatient, 0.5; 95% confidence interval [CI], 0.2 to 1.0; p = 0.045); no other significant differences were identified. Among the 5,627 cases in the late cohort, inpatient UKA had higher rates of any complication (2.53% compared with 0.95% for outpatient UKA; adjusted RR for inpatient, 2.5; 95% CI, 1.4 to 4.3; p = 0.001) and readmission (1.81% compared with 0.88% for outpatient UKA; adjusted RR for inpatient, 2.0; 95% CI, 1.1 to 3.5; p = 0.023). In the propensity-score-matched comparison for the late cohort, inpatient UKA had a higher rate of any complication (RR for inpatient, 2.0; 95% CI, 1.0 to 4.0; p = 0.049) and return to the operating room (RR for inpatient, 4.3; 95% CI, 1.4 to 12.6; p = 0.009). Although the rate of readmission was almost twice as high among inpatients (1.67% compared with 0.84% for outpatients; RR for inpatient, 2.0; 95% CI, 1.0 to 4.1; p = 0.059), this difference did not reach significance with the sample size studied. There was a significant reduction in the overall rate of complications over time (3.44% in the early cohort compared with 2.11% in the late cohort; adjusted RR for late cohort, 0.7; 95% CI, 0.5 to 0.8; p = 0.001), with a more than fourfold reduction among outpatients (3.95% in the early cohort compared with 0.95% in the late cohort; adjusted RR for late cohort, 0.3; 95% CI, 0.1 to 0.5; p < 0.001).

CONCLUSIONS

Outpatient UKA was associated with a lower risk of complications compared with inpatient UKA when contemporary data are examined. We identified a dramatic reduction in complications across the early and late cohorts, suggesting an improvement in quality over time, with the largest improvements seen among outpatients. This shift may represent changes in patient selection or improvements in perioperative protocols.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Introduction of day case hip and knee replacement programme at an inpatient ward is safe and may expedite shortening of hospital stays of traditional arthroplasties

PURPOSE

We investigated the safety of primary hip and knee replacements with same day discharge (SDD) and their effect on length of stay (LOS) of traditional inpatient arthroplasties at our elective orthopaedic ward.

METHODS

200 patients underwent elective, unilateral primary day case total hip (THA, n = 94), total knee (TKA, n = 60) and unicondylar knee replacements (UKA, n = 46). SDD rates, reasons for failure to discharge, readmission, complication and satisfaction rates were recorded at 6-week follow up. Changes in LOS of inpatient arthroplasties (n = 6518) and rate of patients discharged with only one night stay treated at the same ward were tracked from 1 year prior to introduction of day case arthroplasty (DCA) program to the end of observation period.

RESULTS

166 patients (83%) had SDD while 34 (17%) needed overnight stay. Main reasons for failure to discharge were lack of confidence (4%) fainting due to single vasovagal episode (3.5%), urine retention (3%) and late resolution of spinal anaesthesia (3%). 5 patients (3%) had readmission within 6 weeks, including 1 (0.6%) with a partial and treated pulmonary embolism. 163 patients were satisfied with SDD (98%). After launching the DCA program, average LOS of inpatients was reduced from 2.3 days to 1.8 days and rate of discharge with only 1-night stay increased from 12% to around 60%.

CONCLUSION

Introduction of routine SDD hip and knee arthroplasty programme at an elective orthopaedic centre is safe and also may confer wider benefits leading to shorter inpatient hospital stays.

Effects of knee extension exercise starting within 4 h after total knee arthroplasty

PURPOSE

To determine the beneficial effects of knee extension exercise applied from 4 h after TKA.

METHODS

Patients undergoing TKA for osteoarthritis were assigned to early rehabilitation (n = 41) and control rehabilitation (n = 39) groups. Rehabilitation of knee extension exercise was started within 4 h postoperative in the early group and 2 days after surgery in the control group. Joint range of motion and pain were assessed before surgery and at 3 days to 12 months after surgery. Muscle strength and gait parameters were assessed before and 3 weeks after surgery.

RESULTS

Extension range of motion was significantly increased in the early group than the control at 3 days, 3 weeks and 6 months after surgery. In gait parameters, peak knee flexion and extension angles during stance phase were significantly improved in the early group than the control group at 3 weeks after surgery. Flexion range of motion was increased in the early group than the control at 12 months after surgery.

CONCLUSION

Starting knee extension exercise within 4 h after TKA reduced the early loss of extension range of motion and improved gait pattern and seemed to contribute to be better functional outcome one year after surgery.

Mobilization after joint arthroplasty surgery: who benefits from standing within 12 hours?

BACKGROUND

Early mobilization following joint arthroplasty surgery has been shown to be beneficial for patients, but it is unclear whether it is associated with a shorter length of stay (LOS) for both hip and knee arthroplasty (KA) patients.

METHODS

We undertook a retrospective observational study, reviewing the case notes of 386 patients admitted to an enhanced recovery programme for total hip (THA) or total/unicompartmental KA. We evaluated the influence of early mobilization on LOS, adjusting for possible confounders, stratifying by surgery type.

RESULTS

THA patients first mobilized within 12 h of returning to the acute orthopaedic ward following surgery had a significantly shorter mean LOS (mean = 3.6, standard deviation = 1.1) than THA patients who first mobilized 12 or more hours (mean = 4.1, standard deviation = 1.2), P = 0.004. There was no statistical significant difference in the mean LOS between the KA patients mobilized earlier or later.

CONCLUSION

Early mobilization as part of an enhanced recovery programme was associated with decreased LOS for patients having THA; however, this was not the case for KA patients.

Implementing early mobilisation after knee or hip arthroplasty to reduce length of stay: a quality improvement study with embedded qualitative component

BACKGROUND

Models of care for managing total knee or hip arthroplasty (TKA, THA) incorporating early mobilisation are associated with shorter acute length-of-stay (LOS). Few studies have examined the effect of implementing early mobilisation in isolation, however. This study aimed to determine if an accelerated mobilisation protocol implemented in isolation is associated with a reduced LOS without undermining care.

METHOD

A Before-After (quasi-experimental) study was used. Standard practice pre-implementation of the new protocol was physiotherapist-led mobilisation once per day commencing on post-operative Day 1 (Before phase). The new protocol (After phase) aimed to mobilise patients four times by end of Day 2 including an attempt to commence on Day 0; physiotherapy weekend coverage was necessarily increased. Poisson regression modelling was used to determine associations between study period and LOS. Additional outcomes to 12 weeks post-surgery were monitored to identify unintended consequences of the new protocol. Time to first mobilisation (hours) and proportion mobilising Day 0 were monitored to assess protocol compliance. An embedded qualitative component captured staff perspectives of the new protocol.

RESULTS

Five hundred twenty consecutive patients (n = 278, Before; n = 242, After) were included. The new protocol was associated with no change in unadjusted LOS, a small reduction in adjusted LOS (8.1%, p = 0.046), a reduction in time to first mobilisation (28.5 (10.8) vs 22.6 (8.1) hrs, p < 0.001), and an increase in the proportion mobilising Day 0 (0 vs 7%, p < 0.001). Greater improvements were curtailed by an unexpected decrease in physiotherapy staffing (After phase). There were no significant changes to the rates of complications or readmissions, joint-specific pain and function scores or health-related quality of life to 12 weeks post-surgery. Qualitative findings of 11 multidisciplinary team members highlighted the importance of morning surgery, staffing, and well-defined roles.

CONCLUSION

Small reductions in LOS are possible utilising an early mobilisation protocol in isolation after TKA or THA although staff burden is increased likely undermining both sustainability and the magnitude of the change. Simultaneous incorporation of other changes within the pathway would likely secure larger reductions in LOS.

Analgesia effect of premixed nitrous oxide/oxygen during the rehabilitation after total knee arthroplasty: a study protocol for a randomized controlled trial

Background

The morbidity of knee arthritis is increasing among aged people and total knee arthroplasty has been its mainstream treatment to date. Postoperative rehabilitation is an important part of the procedure. However, the intense pain during the functional exercise involved has always been a challenge for both patients and health care professionals. The aim of this study is to test the analgesic effect of a mixture of nitrous oxide/oxygeb (1:1) inhalation for patients who are doing functional exercise 1 month after total knee arthroplasty.

Methods/design

This double-blind, randomized, placebo-controlled study will be implemented in the Rehabilitation Department in the General Hospital of Ningxia Medical University. Patients aged between 50 and 75 years who underwent a primary unilateral total knee arthroplasty are eligible for inclusion. The key exclusion criteria include: epilepsy, pulmonary embolism, intestinal obstruction, aerothorax. The treatment group (A) will receive a pre-prepared nitrous oxide/oxygen mixture plus conventional treatment (no analgesics), and the control group (B) will receive oxygen plus conventional treatment (no analgesics). Patients, physicians, therapists, and data collectors are all blind to the experiment. Assessments will be taken immediately after functional exercise begins (T0), 5 min (T1) after functional exercise begins, and 5 min after functional exercise has finished (T2). Patients will be randomly allocated between a treatment group (A) and a control group (B) in a ratio of 1:1. Primary outcome, including pain severity in the procedure, will be taken for each group. Secondary outcomes include blood pressure, heart rate, oxygen saturation, side effects, knee joint range of motion, Knee Society Score (KSS), rescue analgesia need, and satisfaction from both therapists and patients.

Discussion

This study will focus on exploring a fast and efficient analgesic for patients who are doing functional exercise after total knee arthroplasty. Our previous studies suggested that the prefixed nitrous oxide/oxygen mixture was an efficacious analgesic for the management of burn-dressing pain and breakthrough cancer pain. The results of this study should provide a more in-depth insight into the effects of this analgesic method. If this treatment proves successful, it could be implemented widely for patients doing functional exercise in the rehabilitation department.

Trial registration

ChiCTR-INR-17012891. Registered on 6 October 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3472-7) contains supplementary material, which is available to authorized users.

Impact of early mobilization on length of stay after primary total knee arthroplasty

Background

Decreasing length of stay (LOS) following primary total knee arthroplasty (TKA) has been an important focus by all the stakeholders involved in the delivery of care. LOS is dictated by both the patient and hospital-related factors. The purpose of this study was to determine if early mobilization on post-operative day 0 (POD 0) following primary TKA has an effect on hospital LOS and discharge to home vs. rehabilitation facilities.

Methods

An analysis was performed of consecutive primary TKAs performed at a single institution over one year. Patients were assigned to two groups: POD 0 or POD 1, based on their day of mobilization. Patients were mobilized following surgery based on time of arrival to the orthopaedic floor and availability of physical therapy (PT) resources. The two groups were compared for LOS and discharge disposition using univariate analysis. A total of 408 consecutive TKAs were evaluated and from this group, a total of 143 patients who were mobilized on POD 0 were then matched to 143 patients mobilized on POD 1. There were no significant differences in age, sex, American Society of Anesthesiologists score, or body mass index (BMI) between POD 0 and POD 1 groups.

Results

There was a significant difference in LOS between POD 0 and POD 1 groups, 2.44 vs. 2.80 days (P=0.002). There were also differences in discharge to home vs. rehabilitation, 70.63% of the POD 0 cohort were discharged home compared to 58.74% in POD 1 (P=0.035).

Conclusions

There was a significant reduction in LOS and there were differences in discharge disposition between patients who mobilized on POD 0 vs. POD 1, with more patients mobilized on POD 0 discharged home. Hospitals should work with their total joint arthroplasty programs to mobilize close to 100% of the patients undergoing primary TKA on POD 0 in order to decrease LOS and healthcare expenditure.

Effect of local infiltration analgesia, peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in unicompartmental knee arthroplasty

Background

The aim of the study was to analyze the effect of local infiltration analgesia (LIA), peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in primary unicompartmental knee arthroplasty (UKA).

Methods

Between January 2016 until August 2016, 134 patients underwent primary UKA and were subdivided into four groups according to their concomitant pain and anesthetic procedure with catheter-based techniques of femoral and sciatic nerve block (group GA&FNB, n = 38) or epidural catheter (group SP&EPI, n = 20) in combination with general anesthesia or spinal anesthesia, respectively, and LIA combined with general anesthesia (group GA&LIA, n = 46) or spinal anesthesia (group SP&LIA, n = 30). Outcome parameters focused on the evaluation of pain (NRS scores), mobilization, muscle strength and range of motion up to 7 days postoperatively. The cumulative consumption of (rescue) pain medication was analyzed.

Results

The LIA groups revealed significantly lower (about 50%) mean NRS scores (at rest) compared to the catheter-based groups at the day of surgery. In the early postoperative period, the dose of hydromorphone as rescue pain medication was significantly lower (up to 68%) in patients with SP&EPI compared to all other groups. No significant differences could be detected with regard to grade of mobilization, muscle strength and range of motion. However, there seemed to be a trend towards improved mobilization and muscle strength with general anesthesia and LIA, whereof general anesthesia generally tended to ameliorate mobilization.

Conclusions

Except for a significant lower NRS score at rest in the LIA groups at day of surgery, pain relief was comparable in all groups without clinically relevant differences, while the use of opioids was significantly lower in patients with SP&EPI. A clear clinically relevant benefit for LIA in UKA cannot be stated. However, LIA offers a safe and effective treatment option comparable to the well-established conventional procedures.

The role of elastomeric pumps in postoperative analgesia in orthopaedics and factors affecting their flow rate

Elastomeric pumps are mechanical devices composed of an elastomeric balloon reservoir into which the drug to be infused is stored, a protective casing (used by some manufacturers), a flow controller and a wound catheter. In orthopaedics they are used to provide continuous local infiltration analgesia. In this way patients rely less on other routes of analgesia and thus avoid their systemic side effects. Studies have shown good response to analgesia with these pumps for the first 24 hours but their benefit is not as clear at 48 and 72 hours. There are numerous factors that affect the flow rate of elastomeric pumps. Some are inherent to all elastomeric pumps such as: the pressure exerted by the elastomeric balloon, catheter size, the vertical height of the pump in relation to the wound, viscosity and partial filling. There are also other factors which vary according to the manufacturer such as: the optimal temperature to obtain the desired flow rate as this directly affects viscosity, the dialysate that the analgesic drug is mixed with (ie normal saline or 5% dextrose), and the storage conditions of the fluid to be infused. It is thus essential to follow the clinical guidelines provided by the manufacturer in order to obtain the desired flow rate.

Early rehabilitation after elective total knee arthroplasty

BACKGROUND AND AIM OF THE WORK

Outcomes after TKA surgery are supposed to be related to the intensity and type of post-operative rehabilitation. Aim of this paper is to describe our early rehabilitation protocol following TKA with mini-invasive surgery in the immediate post-operative period and analyze functional recovery and changes in pain scores in these patients.

METHODS

in this observational study, data were collected on 215 total knee arthroplasty patients referred to Orthopedics and Traumatology inpatient ward from July 2012 to January 2014, treated with the same early start rehabilitation protocol. We recorded times to reach functional goals (sitting, standing and assisted ambulation) and pain after the treatment.

RESULTS

length of hospital stay in TKA was 4.6±1.8 days, with a rehabilitation treatment lenght of 3.3±1.3 days. The mean time needed to achieve the sitting position was 2.3±0.7 days, to reach the standing position was 2.6±1.0 days to reach the walking functional goal was 2.9±1.0 days.  Pain NRS scores remained below 4 in the first and second post-operative day and below 3 from the third post-operative day.

CONCLUSION

Our study confirms that rehabilitation started as soon as 24 hours after surgery with mini-invasive approach, enables early verticalization of patients and early recovery of walking with a good control of pain.

Outpatient and Inpatient Unicompartmental Knee Arthroplasty Procedures Have Similar Short-Term Complication Profiles

BACKGROUND

Advances in surgical techniques and anesthesia have made performing unicompartmental knee arthroplasty (UKA) in the outpatient setting a possibility. The touted benefits of outpatient surgery include higher patient satisfaction and reduced costs. However, detailed information on the perioperative outcomes of outpatient compared with inpatient UKA in a large, national patient population in the United States has never been reported. The present study compares perioperative complications between outpatient and inpatient UKAs in the National Surgical Quality Improvement Program database.

METHODS

Patients who underwent UKA were identified in the 2005-2015 National Surgical Quality Improvement Program database. Outpatient procedures were defined as those with length of hospital stay = 0 days, whereas inpatient procedures were defined as those with length of hospital stay = 1-4 days. Patients' characteristics and comorbidities were compared between the two groups. Propensity score matched comparisons were performed for 30-day perioperative complications and readmissions between the two cohorts.

RESULTS

This study included 568 outpatient and 5312 inpatient UKA cases. After propensity matching to control potential confounding factors, statistical analysis revealed no significant difference in any perioperative complications or any postdischarge complications between the outpatient and inpatient cohorts. Notably, the rate of 30-day readmissions between the two cohorts was not statistically different.

CONCLUSION

Based on the perioperative outcome measures assessed in this study, outpatient UKA can be appropriately considered in carefully selected patients based on the lack of differences in rates of 30-day perioperative complications and readmissions between the outpatient and matched inpatient groups.

Outpatient surgery for unicompartmental knee arthroplasty is effective and safe

PURPOSE

There has been increasing interest in accelerated programs for knee arthroplasty. We examined the efficacy and safety of an outpatient surgery (OS) pathway in patients undergoing unicompartmental knee arthroplasty (UKA).

METHODS

This case-controlled study evaluates patients operated for UKA in an OS pathway (n = 20) compared to rapid recovery (RR), the current standard (n = 20). We investigated whether patients could be discharged on the day of surgery, resulting in comparable or better outcome by means of adverse events (AEs) in terms of pain (numerical rating scale, NRS), incidences of postoperative nausea and vomiting (PONV) and opiate use (<48 h postoperatively), complication and readmission rates (<3 months postoperatively). Patient-reported outcome measures (PROMS) were obtained preoperatively and 3 months postoperatively.

RESULTS

Postoperative pain (NRS > 5) was the most common reason for prolonged hospital stay in the OS pathway. Eighty-five per cent of the patients were discharged on the day of surgery, whereas 95 % of the patients were discharged on postoperative day 3 in the RR pathway. Overall, median pain scores in both pathways did not exceed a NRS score of 5, without significant differences (RR vs. OS) in the number of patients with PONV (4 vs. 2) and opiate use (11 vs. 9) <48 h postoperatively. At 3 months postoperatively, no significant differences were found for AEs and PROMS between both pathways.

CONCLUSION

The results of this study illustrates that an OS pathway for UKA is effective and safe with acceptable clinical outcome. Well-established and adequate standardized protocols, inclusion and exclusion criteria and a change in mindset for both the patient and the multidisciplinary team are the key factors for the implementation of an OS pathway.

LEVEL OF EVIDENCE

Case-control study, Level III.

Cost Comparison of Outpatient Versus Inpatient Unicompartmental Knee Arthroplasty

Background:

Outpatient unicompartmental knee arthroplasty (UKA) has been shown to be safe and feasible when compared with inpatient surgery; however, no studies have evaluated the cost-effectiveness and cost-benefit of performing outpatient versus inpatient UKA.

Hypothesis:

Significant cost savings can be achieved by transitioning UKAs from an inpatient to an outpatient procedure in an outpatient surgical facility, with no appreciable difference in complication or readmission rates.

Study Design:

Economic and decision analysis; Level of evidence, 3.

Methods:

A retrospective chart review of 25 consecutive medial UKAs was performed. A total of 10 inpatient UKAs with a mean length of stay of 1.6 days (range, 1-4 days) and 12 outpatient UKAs were included in the final analysis. A simple difference in costs incurred, reimbursements, and percentage difference between inpatient and outpatient surgery in an outpatient surgical facility was calculated. Charges were subdivided into surgical facility fees, inpatient room charges, operating room supply fees, and other fees. Secondary outcome measures included reason for greater than 1 day stay for the inpatient UKAs, complications, readmissions, and the type of regional anesthesia utilized.

Results:

The outpatient UKA charges were a mean $20,500 less per patient than the inpatient average charge of $46,845. The primary cost savings were attributed to the outpatient surgical facility fee, which averaged $3800 per patient, while the inpatient facility charge was 350% more expensive at $13,200 per patient (approximately $9500 savings). On the inpatient side, the average reimbursement was 55% of charges, or $25,550. For outpatient procedures, the average reimbursement was 47%, or $12,370. There was no difference between the inpatient and outpatient groups in terms of complications or readmissions.

Conclusion:

This work demonstrated that significant cost savings of roughly 50% can be achieved with an outpatient UKA protocol done at an outpatient surgical facility. Not only is it feasible and economically attractive to perform outpatient UKA, but it can reduce inpatient bed occupancy and resource allocation for a busy hospital.

Does obesity influence early outcome of fixed-bearing unicompartmental knee arthroplasty?

Obesity is a known major contributing risk factor for knee osteoarthritis (OA). It is also believed that obese unicompartmental knee arthroplasty (UKA) patients tend to have poorer outcome and possible early failure. The purpose of this study is to investigate the early outcome of obese UKA patients in a single institution. Patients who underwent fixed bearing medial UKA in between year 2005 and 2010 were included in this study. They were divided into four groups based on Body Mass Index (BMI): 25 kg/m² (Control); 25-29.9 kg/m² (Overweight); 30-34.9 kg/m² (Obese); >35 kg/m² (Severely Obese). Functional outcome was assessed using Knee Society Score (KSS), Oxford Knee Score (OKS) and Short-form 36 (SF-36). One-way ANOVA with Bonferroni post-hoc test was used to compare the four groups for quantitative variables. There were 673 patients in this study, no significant difference between the four BMI groups for gender and side of operated knee ( p > 0.05). The functional outcome of all four groups at 2 years were comparable (all p > 0.05). At a mean follow up of 5.4 (range 2.5, 8.5) years, 9 revision surgeries (1.3%) were identified. The mean duration from initial surgery to revision surgery was 49 months (Range 6, 90). Patients' pre-operative BMI did not influence the early outcome of UKA patients. However, patients with higher BMI had relatively lower functional score prior to the surgery and tended to be younger. This did not translate to early failure and the functional improvement was similar among all four groups.

Day of surgery discharge after unicompartmental knee arthroplasty: an effective perioperative pathway

Day of surgery (DOS) discharge after unicompartmental knee arthroplasty (UKA) allows for safe, efficient care of the appropriately selected patient. Refinement of our perioperative pathway over the last decade has allowed for successful DOS discharge of 160 consecutive patients. The cohort averaged 65 years and American Society of Anesthesiology class was 1-3 (mean, 1.8). Perioperative pain control included a preoperative single shot femoral nerve block. Mean recovery room time was 121 (SD = 37) minutes. No patient required overnight admission for uncontrolled pain or nausea. Significant improvements in Knee Society Clinical Rating System (KSCRS) scores and high patient satisfaction were observed. This study details critical components of our simple perioperative pathway that can be utilized to safely perform UKA with discharge on the DOS.

Management of Periprosthetic Fracture in Unicompartmental Knee Arthroplasty Patients: A Case Series

Unicompartmental knee arthroplasty (UKA) has been one of the treatment modality specifically for unicompartmental osteoarthritis of the knee. The advantages of UKA are faster recovery period, shorter length of hospital stay, reduced morbidity, and good functional outcome. However, one of the complications in UKA is periprosthetic fracture where most papers suggested a surgical intervention such as revision to total knee replacement. In our six years of experience with UKA surgery from 2005 to 2010, we encountered six periprosthetic fractures out of 966 knees that were operated on among 901 patients. Five patients were treated conservatively by casting and were advised not to bear weight on the affected side. One patient was revised to total knee replacement immediately. Each patient underwent a series of scoring system such as Knee Society Clinical Rating and Oxford Questionnaire to evaluate the outcome of treatment. The results were variable with only one patient showing reasonable improvement by conservative management alone. Another three patients did not show significant functional improvements despite the fractures healing. One patient developed non-union and had to undergo internal fixation to correct the deformity. The patient who underwent a revision to total knee replacement showed significant improvement. We conclude that surgical intervention produced better outcome. Revision to total knee replacement was the preferred treatment.

BASK presentations: progress to journal publication

Scientific conferences, such as the British Association for Surgery of the Knee (BASK) annual meeting, provide an important channel for the exchange of information between researchers. However, the ultimate means of disseminating research information is publication in a relevant peer-reviewed journal. The goal of this study was to follow up published abstracts in the Journal of Bone and Joint Surgery, British Volume supplement from the annual BASK conference and determine how many presented abstracts progressed to article publication in a peer-reviewed journal. Combined Google Scholar and PubMed searches of 602 BASK abstract titles over a 10-year period were performed, and the resulting articles were reviewed to confirm that they were directly associated with the corresponding abstracts. Two hundred (33.2%) abstracts presented at BASK conferences over a 10-year period were found in online or print format. This amount is comparable with other similar conferences' publication rates. Only one-third of abstracts presented at the BASK conference were converted to journal publication as full articles. This may be due to multiple rejections, lack of time, relocation of the authors, or a reluctance to publish negative findings. Alternatively, changes in an abstract's title for publication prevents online search engines from identifying the final article and may explain some disparity. Furthermore, presented abstracts may not survive the strict peer-review process required for journal publication. Because these findings from BASK mirror other specialty meetings, clinicians should accept the results of orthopedic meeting proceedings with some level of caution.

Intra-articular local anaesthetic on the day after surgery improves pain and patient satisfaction after Unicompartmental Knee Replacement: a randomised controlled trial

Intra-operative local anaesthetic infiltration provides good early pain relief after Unicompartmental Knee Replacement (UKR). However, appreciable pain may occur on the day after surgery. The purpose of this double-blinded, prospective randomised controlled trial was to evaluate the effectiveness of a bolus of local intra-articular anaesthetic given early on the day after surgery. Forty-four patients were randomised to receive an intra-articular injection, via an epidural catheter inserted at operation, of either 20 ml 0.5% plain bupivacaine or 20 ml normal saline. All patients received a femoral nerve block with 20 ml prilocaine 1% and local anaesthetic infiltration by the surgeon. Patients injected with bupivacaine had significantly less (p<0.001) pain than control patients immediately (mean pain score 1.82 v 6.1) and 6 hours (2.5 v 5.7) after injection. Patient satisfaction was also significantly greater (p<0.001) in the local anaesthetic group. We conclude that a bolus dose of intra-articular bupivacaine early on the day after surgery dramatically improves pain control after UKR and improves patient satisfaction.

Outpatient unicompartment knee arthroplasty with indwelling femoral nerve catheter

Contemporary multimodal anesthesia regimens allow the performance of unicompartment knee arthroplasty (UKA) on an outpatient basis. Our initial pilot experience is presented using a continuous femoral nerve block as an adjunct for 24 patients classified as American Society of Anesthesiology class 1 (14 men, 10 women; median age, 56 years; range, 46-72 years). After minimally invasive UKA, patients documented their pain and oral medication use while at home for the first 5 days. Adverse events, medication adverse effects, and the amount of infused ropivacaine were recorded. Median pain scores for the first 3 days were 1, 2, and 2 (at rest) and 4, 5, and 3 (during physical therapy). Eighteen patients (75%) required less than 4 mg oral hydromorphone/d. Of the 18, 10 (42%) did not require supplemental oral opioids. The median catheter use was 3 days. Our results suggest that with careful patient selection and adequate teaching, continuous femoral nerve blocks may be used as part of a multimodal pain regimen to assist the delivery of outpatient UKA with high patient satisfaction.

Intraarticular vs. extraarticular ropivacaine infusion following high-dose local infiltration analgesia after total knee arthroplasty: a randomized double-blind study

BACKGROUND AND PURPOSE

Ropivacaine infusion following high-volume local infiltration analgesia has been shown to be effective after total knee arthroplasty, but the optimum site of administration of ropivacaine has not been evaluated. We compared the effects of intraarticular and extraarticular adminstration of the local anesthetic for postoperative supplementation of high-volume local infiltration analgesia.

PATIENTS AND METHODS

In this double-blind study, 36 rheumatic patients aged 51-78 years with physical status ASA 2-3 who were scheduled for total knee arthroplasty were randomized into 2 groups. All patients received wound infiltration at the end of surgery with 300 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine (total volume 156 mL). A tunneled catheter was randomly placed either extraarticularly or intraarticularly. Continuous infusion of ropivacain (0.5%, 2 mL/h) was started immediately and was maintained during the next 48 h. Pain intensity at rest, on movement, and with mobilization was estimated by the patients and the physiotherapist; rescue morphine consumption was recorded.

RESULTS

As estimated by the patients, ropivacaine administered intraarticularly did not improve analgesia relative to extraarticular infusion, but improved the first mobilization. The incidence of high intensity of pain (VAS 7-10) was less in the group with intraarticular infusion. Analgesic requirements were similar in the 2 groups (47 mg and 49 mg morphine). No complications of postoperative wound healing were seen and there were no toxic side effects.

INTERPRETATION

Continuous infusion of ropivacaine intraarticulary did not improve postoperative analgesia at rest relative to extraarticular administration, but it appeared to reduce the incidence of high pain intensity during first exercises, and could therefore be expected to improve mobilization up to 24 h after total knee arthroplasty.

Benefits of starting rehabilitation within 24 hours of primary total knee arthroplasty: randomized clinical trial

Objective: To compare the benefits of initiating rehabilitation treatment within 24 hours versus 48–72 hours after total knee arthroplasty for osteoarthritis.

Design: Experimental study with clinical trial design.

Subjects: Patients undergoing primary total knee arthroplasty for osteoarthritis were randomly assigned to experimental (n = 153) and control (n = 153) groups.

Interventions: Rehabilitation was started within 24 hours post surgery in the experimental group and between 48 hours and 72 hours post surgery in the controls.

Main measures: Measurement variables included joint range of motion, muscle strength, pain, autonomy, gait and balance.

Results: In comparison with the controls, the experimental group showed significantly shorter hospital stay (by (mean ± standard deviation) 2.09 ± 1.45 days; P < 0.001), fewer rehabilitation sessions until medical discharge (by 4.95 ± 2.34; P < 0.001), lesser pain (by 2.36 ± 2.47 points; P < 0.027), greater joint range of motion in flexion (by 16.29 ± 11.39 degrees; P < 0.012) and extension (by 2.12 ± 3.19; P < 0.035), improved strength in quadriceps (by 0.98 ± 0.54; P < 0.042) and hamstring muscles (by 1.05 ± 0.72; P < 0.041), and higher scores for gait (P < 0.047) and balance (P < 0.045).

Conclusion: Initiation of rehabilitation within 24 hours after total knee arthroplasty reduces the mean hospital stay and number of sessions required to achieve autonomy and normal gait and balance.

The effect of local anaesthetic wound infiltration on chronic pain after lower limb joint replacement: a protocol for a double-blind randomised controlled trial

BACKGROUND

For the majority of patients with osteoarthritis (OA), joint replacement is a successful intervention for relieving chronic joint pain. However, between 10-30% of patients continue to experience chronic pain after joint replacement. Evidence suggests that a risk factor for chronic pain after joint replacement is the severity of acute post-operative pain. The aim of this randomised controlled trial (RCT) is to determine if intra-operative local anaesthetic wound infiltration additional to a standard anaesthesia regimen can reduce the severity of joint pain at 12-months after total knee replacement (TKR) and total hip replacement (THR) for OA.

METHODS

300 TKR patients and 300 THR patients are being recruited into this single-centre double-blind RCT. Participants are recruited before surgery and randomised to either the standard care group or the intervention group. Participants and outcome assessors are blind to treatment allocation throughout the study. The intervention consists of an intra-operative local anaesthetic wound infiltration, consisting of 60 mls of 0.25% bupivacaine with 1 in 200,000 adrenaline. Participants are assessed on the first 5 days post-operative, and then at 3-months, 6-months and 12-months. The primary outcome is the WOMAC Pain Scale, a validated measure of joint pain at 12-months. Secondary outcomes include pain severity during the in-patient stay, post-operative nausea and vomiting, satisfaction with pain relief, length of hospital stay, joint pain and disability, pain sensitivity, complications and cost-effectiveness. A nested qualitative study within the RCT will examine the acceptability and feasibility of the intervention for both patients and healthcare professionals.

DISCUSSION

Large-scale RCTs assessing the effectiveness of a surgical intervention are uncommon, particularly in orthopaedics. The results from this trial will inform evidence-based recommendations for both short-term and long-term pain management after lower limb joint replacement. If a local anaesthetic wound infiltration is found to be an effective and cost-effective intervention, implementation into clinical practice could improve long-term pain outcomes for patients undergoing lower limb joint replacement.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN96095682.

Initial experience with the oxford unicompartmental knee arthroplasty

Our initial experience with mobile bearing medial compartment unicompartmental arthroplasty (UKA) is presented to highlight lessons that have been learned to avoid short-term failures. Consecutive cases of the Oxford medial UKA performed between February 2001 and April 2006 were reviewed to derive those cases that were revised to total knee arthroplasty (TKA). There were 545 patients available with mean age and body mass index of 65.0 and 30.1, respectively. At final follow-up, 32 patients were revised for lateral compartment arthritis, aseptic component loosening, persisting medial or anterior pain and dislocated meniscal bearing. Revisions were performed with primary unconstrained TKA implants with no stems or wedges required. Our results seem to reflect those seen in registries confirming an earlier higher revision rate and highlight the technical issues of overstuffing the compartment, inadequate cementation technique, and strict adherence to patient selection.

Similar clinical outcome after unicompartmental knee arthroplasty using a conventional or accelerated care program: a randomized, controlled study of 40 patients

BACKGROUND AND PURPOSE Over the last 5 years, there has been increasing interest in reducing length of hospitalization (LOS) through accelerated programs. We examined the clinical outcome of patients undergoing a unicompartmental knee replacement (UKR) in an accelerated care program (A group) compared to a conventional care program (C group).

METHODS

40 patients randomized into 2 groups were included (A group: 17 patients; C group: 23 patients). Nausea, micturition problems, lower limb dysfunction, pain (VAS), opiate consumption, Knee Society score (KSS), day of discharge, rehospitalization within 3 months, contact with a general physician or nurse, and level of satisfaction were registered. Patients in the A group attended an information meeting. An intraarticular infiltration with Marcaine and adrenaline was used peroperatively. Patients in the C group had an epidural pump for 2 or 3 days. Patients in the A program were treated with NSAID and paracetamol postoperatively. Opiates were used in both groups in the case of breakthrough pain. The patients were considered ready for discharge when they were able to climb stairs to the second floor within 5 min.

RESULTS

The median length of stay was 1 (1-3) day in the A group and 6 (4-7) days in the C group. The median pain score (VAS) at day 0 was 1 (0-3) in the A group and 5 (0-8) in the C group (p < 0.001). 11/23 of the patients in the C group had weakness of the lower limbs on day 1 due to the epidural; all patients in the A group were exercising on the day of the operation. Micturition problems necessitating intermediate catherization were more frequent in patients in the C program (19/23) than in patients in the A programme (3/17) (p = 0.001). There were no statistically significant differences between the two groups concerning nausea, average pain on days 1 and 2, use of opioids (during the first week postoperatively), KSS, contact with primary sector, level of satisfaction, or level of confidence.

INTERPRETATION

We achieved a reduction in LOS of 5 days without affecting the clinical outcome.

Is recovery faster for mobile-bearing unicompartmental than total knee arthroplasty?

How does unicompartmental compare with total knee arthroplasty in durability, incidence of complications and manipulations, recovery, postoperative function, and return to sport and work? We matched 103 patients (115 knees) treated with a mobile-bearing unicompartmental device through July 2005 to a selected group of 103 patients (115 knees) treated with cruciate retaining total knee arthroplasty for bilaterality, age, gender and body mass index. Patients who underwent a unicompartmental surgery had better range of motion at discharge and shorter hospital stay than those who had a total knee arthroplasty (77 degrees versus 67 degrees and 1.4 versus 2.2 days). At 6 weeks, Knee Society functional scores and range of motion were higher for unicompartmental than total knees (63 versus 55 and 115 degrees versus 110 degrees). Patient-perceived Oxford scores were similar between groups (unicompartmental 5.4 versus total 4.1). Average times to return to work and sport were similar for both groups. Minimally invasive unicompartmental knee arthroplasty demonstrated better early ROM, shorter hospital stays, and improved functional scores. No advantage was seen in terms of return to work, return to sport, or Oxford scores. The data suggest minimally invasive unicompartmental arthroplasty using a rapid recovery protocol allows patients a faster return to a more functional level than total knee arthroplasty.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the guidelines online for a complete description of level of evidence.

Reduced hospital stay, morphine consumption, and pain intensity with local infiltration analgesia after unicompartmental knee arthroplasty

BACKGROUND AND PURPOSE

The degree of postoperative pain is usually moderate to severe following knee arthroplasty. We investigated the efficacy of local administration of analgesics into the operating area, both intraoperatively and postoperatively.

METHODS

40 patients undergoing unicompartmental knee arthroplasty (UKA) were randomized into 2 groups in a double-blind study (ClinicalTrials.gov identifier: NCT00653926). In group A (active), 200 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine (total volume 106 mL) were infiltrated intraoperatively into the soft tissue, while in group P (placebo), no injections were given. 21 hours postoperatively, 150 mg ropivacain, 30 mg ketorolac, and 0.1 mg epinephrine were injected intraarticularly via a catheter in group A, whereas patients in group P were injected with the same volume of saline (22 mL).

RESULTS

Median hospital stay was shorter in group A than in group P: 1 (1-6) days as opposed to 3 (1-6) days (p < 0.001). Postoperative pain in group A was statistically significantly lower at rest after 6 h and 27 h and on movement after 6, 12, 22, and 27 h. Morphine consumption was statistically significantly lower in group A for the first 48 h, resulting in a lower frequency of nausea, pruritus, and sedation. Postoperatively, there were improved functional scores (Oxford knee score and EQ-5D) in both groups relative to the corresponding preoperative values.

INTERPRETATION

Local injection of analgesics periarticularly at the end of the operation and intraarticularly at 21 h postoperatively provided excellent pain relief and earlier home discharge following UKA. There was a high degree of patient satisfaction in both groups after 6 months (Clinical Trials.gov: NCT 00653926).

Early discharge after hip arthroplasty with home support: experience at a UK District General Hospital

One hundred and thirty-eight consecutive patients undergoing hip arthroplasty and accelerated discharge at our institution over 6 months were reviewed. Our protocol included transfer to a dedicated home support team. No minimal incision techniques or special anaesthetic/analgesic techniques were used. 66% of patients having primary joint replacements went home by the third post operative day and 91% by the fourth day. Re-admission rates were under 1% whilst under the care of the home support team. Patient satisfaction was high. 94% said they would use the service again. This protocol has saved over 1500 bed days per year whilst maintaining standards of care.

[Revision of unicompartmental knee arthroplasty]

Despite the good midterm survivorship reported for unicondylar knee arthroplasty, an increase in revision surgery has to be expected due to increased replacement rates. The reasons for failure as well as distribution are different for unicondylar knee arthroplasty compared to total knee arthroplasty. The main reasons for revision are aseptic loosening and the progression of osteoarthritis. In most cases, unicondylar knee arthroplasty will be revised to total knee arthroplasty. To obtain good revision results, the cause of implant failure has to be analysed carefully. In the case of contained bone defects, the reconstruction can be supported with bone grafting. For those cases with uncontained defects, implants with augmentation and, in some cases, stem extensions are needed. The modularity of the revision implant should cover different intraoperative requirements.

Hands-on robotic unicompartmental knee replacement: a prospective, randomised controlled study of the acrobot system

We performed a prospective, randomised controlled trial of unicompartmental knee arthroplasty comparing the performance of the Acrobot system with conventional surgery. A total of 27 patients (28 knees) awaiting unicompartmental knee arthroplasty were randomly allocated to have the operation performed conventionally or with the assistance of the Acrobot. The primary outcome measurement was the angle of tibiofemoral alignment in the coronal plane, measured by CT. Other secondary parameters were evaluated and are reported. All of the Acrobot group had tibiofemoral alignment in the coronal plane within 2 degrees of the planned position, while only 40% of the conventional group achieved this level of accuracy. While the operations took longer, no adverse effects were noted, and there was a trend towards improvement in performance with increasing accuracy based on the Western Ontario and McMaster Universities Osteoarthritis Index and American Knee Society scores at six weeks and three months. The Acrobot device allows the surgeon to reproduce a pre-operative plan more reliably than is possible using conventional techniques which may have clinical advantages.

Minimally invasive surgery vs conventional exposure using the Miller-Galante unicompartmental knee arthroplasty: a randomized radiostereometric study

Forty-one patients were randomized to a cemented Miller-Galante unicompartmental (Zimmer, Warsaw, Ind) knee arthroplasty inserted with either minimally invasive surgery or with a standard exposure. Clinical data and conventional radiographs were recorded and patients were followed with radiostereometric analysis to measure migration rate of the tibial component. The rehabilitation of patients operated through a small incision was faster, and there was a significant difference in days of hospitalization (P = .03). No statistical significant difference was found between the 2 groups regarding clinical or radiographic data. The Hospital for Special Surgery score was 96 and 92, respectively, for the minimally invasive surgery and conventional group at 2 years. The limb alignment was equal in both groups with a mean femorotibial axis of 182 degrees after surgery. The rate of migration for tibial components was very small, with a maximal total point motion of 0.8 mm for both groups after 2 years follow-up.

Single photon emission computed tomography in planning unicompartmental knee arthroplasty. A prospective study examining the association between scan findings and intraoperative assessment of osteoarthritis

The aim of this study was to determine the relationship between preoperative single photon emission computed tomography (SPECT) scan findings and intraoperative assessments of knee osteoarthritis (OA) in patients undergoing tibiofemoral unicompartmental knee arthroplasty (UKA). Fifty knees in 46 patients undergoing UKA were investigated preoperatively with a SPECT scan to confirm unicompartmental disease. There were 38 men and 12 women in the cohort with an average age of 63 years (range 44-78). The SPECT scan uptake in each compartment of the knee was graded by a single radiologist and these findings were compared with intraoperative assessments of OA (size and grade of lesion), made by two experienced surgeons, blinded to the scan findings. Significant association was demonstrated between scan findings and OA in all compartments of the knee (p<0.05), and this was strongest in the medial compartment and weakest in the patellofemoral compartment and lateral tibial plateau. We conclude that SPECT scan is a useful imaging modality in the planning of medial tibiofemoral UKA to confirm unicompartmental disease. The lower degree of association between scan findings and OA encountered in the patellofemoral compartments and lateral tibial plateau indicates that greater vigilance should be exercised in the intraoperative assessment of these areas.

Efficacy of an accelerated recovery protocol for Oxford unicompartmental knee arthroplasty--a randomised controlled trial

Unicompartmental knee arthroplasty (UKA) is appropriate for one in four patients with osteoarthritic knees. This study was performed to compare the safety, effectiveness and economic viability of a new accelerated protocol with current standard care in a state healthcare system. A single blind RCT design was used. Eligible patients were screened for NSAID tolerance, social circumstances and geographical location before allocation to an accelerated recovery group (A) or standard care group (S). Primary outcome was the Oxford Knee Assessment at 6 months post operation, compared using independent Mann-Whitney U-tests. A simple difference in costs incurred was calculated. The study power was sufficient to avoid type 2 errors. Forty-one patients were included. The average stay for Group A was 1.5 days. Group S averaged 4.3 days. No significant difference in outcomes was found between groups. The new protocol achieved cost savings of 27% and significantly reduced hospital bed occupancy. In addition, patient satisfaction was assessed as greater with the accelerated discharge than with the routine discharge time. The strict inclusion criteria meant that 75% of eligible patients were excluded. However, a large percentage of these were due to the distances patients lived from the hospital.

Accelerated rehabilitation after total knee replacement

This study records the length of hospital stay of 50 total knee arthroplasty patients involved in an accelerated postoperative rehabilitation protocol, and a control group of patients undergoing routine rehabilitation. This protocol involved modifications to normal knee replacement procedure, including infiltration of bupivacaine and adrenaline to the divided tissue layers at the time of surgery, spinal anaesthesia, and mobilisation on the day of surgery. These modifications were combined with an organised multidisciplinary approach anticipating issues that may delay discharge. In addition, patients and hospital staff were encouraged to expect an earlier discharge from the hospital. The mean length of hospital stay after surgery was reduced to 3.6 (S.D. 1.0) days, from a previous departmental average of 10.5 days. The control group inpatient stay was 6.6 (S.D. 2.6) days. Plasma bupivacaine levels were found to be well within safe levels, and pain records indicated that the protocol did not cause increased levels of discomfort. American Knee Society and Oxford knee scores demonstrated good levels of knee function at 6 weeks post surgery. In addition, it was noted that no postoperative blood transfusions were required. This is regarded as a significant further benefit.

Haemoglobin levels following unicompartmental knee arthroplasty: influence of transfusion practice and surgical approach

A retrospective review was undertaken of preoperative and day 3 postoperative haemoglobin (Hb) levels in all unicompartmental knee arthroplasty (UKA) procedures performed by a single surgeon. Sixty-six UKAs were performed using the same prosthesis through an open approach with patella eversion. This group was compared with 212 UKAs performed using a minimally invasive approach without patella eversion, with an implant and instrumentation specifically devised for this approach. Both groups were well matched for patient demographics, surgical and anaesthetic techniques, thromboprophylaxis, and postoperative regimes. All patients received transfusions with pre-donated blood, except the unilateral minimally invasive approach group. An analysis of covariance was undertaken to examine the influence of the surgical approach and whether surgery was unilateral or bilateral, taking into account preoperative Hb levels and units of blood transfused. The average fall in Hb following UKA, adjusted for other variables, was 2.73 g/dl with an open approach compared to 1.82 g/dl with a minimally invasive approach. This difference was significant (p=0.0044). The average postoperative Hb in the minimally invasive group was 12.05 g/dl (range, 8.8 to 15.8 g/dl). Patients undergoing unilateral minimally invasive UKA are unlikely to develop symptomatic anaemia and should not be required to predonate blood or undergo transfusion.

Die mediale Schlittenprothese mit mobilem Polyethylenmeniskus

Medial unicompartmental knee replacement (UKR) has many advantages over total replacement (TKR) including better function and reduced morbidity. However, the long-term failure rates of fixed-bearing UKR are high, especially because of polyethylene wear. The fully congruent mobile bearing of the Oxford UKR exhibits minimal polyethylene wear, failure from this cause does not seem to occur before 10 years. The instrumentation allows precise implantation to restore isometric function of the ligaments. During its 20 years development, the limits of usefulness of the implant have been established and found to include about one in four knees requiring replacement for osteoarthritis. In an independent series, using these criteria, the 15 year survival was 94%. Since 1998, the phase 3 implant has been used with modified instruments through a small incision, avoiding damage to the extensor mechanism. Patients now recover about three times faster than after TKR, and regain much better flexion (mean 135 degrees ). The current evidence supports that the minimally invasive Oxford UKR should be seriously considered as primary treatment for anteromedial compartment osteoarthritis-provided the appropriate surgical expertise is available.

Comparison of a mobile with a fixed tibial bearing unicompartimental knee prosthesis: a prospective randomized trial using a dedicated outcome score

Between February 1996 and December 1997, forty consecutive patients with medial compartment knee arthritis were assigned randomly into two groups. All underwent a unicompartimental knee replacement. The tibial prosthesis in group A (20 knees) had a fixed bearing and in group B (20 knees) a mobile bearing. The average age was 69. Five in group A and 71 in group B. Pre-operatively, and at an average follow-up of 5.7 years, all the knees were assessed using both a dedicated UKR score specifically developed and adopted by the Italian Orthopaedic Unicompartimental Knee Replacement Users Group (GIUM) and the Knee Society Score. During surgery in group B we experienced a medial tibial plateau fracture fixed intra-operatively. One prosthesis in group A required an early revision to a TKR because of a continuous pain without any evident sign of loosening. There were no meniscal dislocations in group B. No statistically significant difference in outcome was observed between the two groups at the latest follow-up.

Is closed-suction drain necessary in unicompartmental knee replacement? A prospective randomised study

In a prospective randomised trial we evaluated the use of a post-operative closed-suction drain in unicompartmental knee replacement (UKR). Seventy-eight patients were divided into two groups: one without a post-operative closed-suction drain (Group A) and one with a drain (Group B). Both groups were matched for age, sex and pre-operative haemoglobin. In group A we observed a lower day one post-operative analgesic requirement, smaller knee circumference 3 days post-operatively and less local wound complications. Drain usage in UKR resulted in no significant advantage in post-operative pain, range of motion and hospital stay. Post-operative drainage does, however, increase the cost of the procedure both in labour and equipment expenditure. No deep infections occurred in either group during the follow-up period. We conclude that avoiding post-operative closed-suction drainage in UKR does not influence the outcome.

Unicompartmental knee arthroplasty: an intermediate report of survivorship after the introduction of a new system with analysis of failures

We describe the outcome of a series of 66 consecutive porous coated low contact stress (LCS) unicompartmental knee arthroplasty (UKA) cases performed in 52 patients for osteoarthritis (OA) by a single surgeon. Both survival, using the endpoint of revision for any cause, and knee function, using the Oxford knee score (OKS) as a validated outcome measure, were established in a retrospective review. At an average postoperative follow-up period of 5.9 years (range 5.1-6.6), there were 8 knees in patients who had died and 58 knees in those who were still living. We established the status of all knees, and prosthesis survival at 5 years was 89.7% (95% confidence interval, 81.6% to 97.7%). Technical errors were responsible for four of six failures and included progression of lateral compartment OA due to overcorrection, a medial tibial stress fracture due to poor pin placement, and a case where cement was required and poor cementing technique lead to early tibial component loosening. In the remaining 52 knees, the average preoperative OKS had improved significantly (p<0.0001) from 37.0 (range, 17-49) to a postoperative score of 20.5 (range, 13-32). We conclude that the functional results following UKA compare favourably to total knee arthropasty (TKA); however, the survivorship of this series does not match that of published reports of TKA. The introduction of a new system of UKA includes the risk of early failures due to surgeon error, even when a surgeon is competent in UKA, warranting careful surveillance during this period.

Unicompartmental knee arthroplasty: new indications, more complications?

Despite mixed results with unicompartmental knee arthroplasty (UKA) in the 1970s, the UKA was established as a reliable procedure in the low-demand, elderly patient. Dependable results up to a decade prompted the idea that UKA may work equally well in the younger patient. Expanded indications for UKA are being evaluated: might higher failure rates and difficult revisions emerge from younger, more active patients?

Minimally invasive unicompartmental knee replacement: rationale and correct indications

In the early 1990s, unicompartmental knee replacements (UKRs) were almost forgotten as an option for the management of unicompartmental arthritis of the knee, and the two principal surgical options became proximal tibial osteotomy and total knee replacement. The recent introduction of minimally invasive techniques has renewed interest in uni-compartmental knee replacement. The proposed advantages of UKR over proximal tibial osteotomy include more predictable relief of pain, quicker recovery, and better long-term results. In appropriate cases, it has advantages over total arthroplasty in providing more physiologic function, better range of movement, easier salvage in case of failure, and quicker recovery because of minimally invasive techniques.