Robotic arm-assisted versus conventional unicompartmental knee arthroplasty: Exploratory secondary analysis of a randomised controlled trial

Objectives

This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group.

Methods

A total of 139 patients were recruited from a single centre. Patients were randomised to receive either a manual UKA implanted with the aid of traditional surgical jigs, or a UKA implanted with the aid of a tactile guided robotic arm-assisted system. Outcome measures included the American Knee Society Score (AKSS), Oxford Knee Score (OKS), Forgotten Joint Score, Hospital Anxiety Depression Scale, University of California at Los Angeles (UCLA) activity scale, Short Form-12, Pain Catastrophising Scale, somatic disease (Primary Care Evaluation of Mental Disorders Score), Pain visual analogue scale, analgesic use, patient satisfaction, complications relating to surgery, 90-day pain diaries and the requirement for revision surgery.

Results

From the first post-operative day through to week 8 post-operatively, the median pain scores for the robotic arm-assisted group were 55.4% lower than those observed in the manual surgery group (p = 0.040).

At three months post-operatively, the robotic arm-assisted group had better AKSS (robotic median 164, interquartile range (IQR) 131 to 178, manual median 143, IQR 132 to 166), although no difference was noted with the OKS.

At one year post-operatively, the observed differences with the AKSS had narrowed from a median of 21 points to a median of seven points (p = 0.106) (robotic median 171, IQR 153 to 179; manual median 164, IQR 144 to 182). No difference was observed with the OKS, and almost half of each group reached the ceiling limit of the score (OKS > 43). A greater proportion of patients receiving robotic arm-assisted surgery improved their UCLA activity score.

Binary logistic regression modelling for dichotomised outcome scores predicted the key factors associated with achieving excellent outcome on the AKSS: a pre-operative activity level > 5 on the UCLA activity score and use of robotic-arm surgery. For the same regression modelling, factors associated with a poor outcome were manual surgery and pre-operative depression.

Conclusion

Robotic arm-assisted surgery results in improved early pain scores and early function scores in some patient-reported outcomes measures, but no difference was observed at one year post-operatively. Although improved results favoured the robotic arm-assisted group in active patients (i.e. UCLA ⩾ 5), these do not withstand adjustment for multiple comparisons.

Cite this article: M. J. G. Blyth, I. Anthony, P. Rowe, M. S. Banger, A. MacLean, B. Jones. Robotic arm-assisted versus conventional unicompartmental knee arthroplasty: Exploratory secondary analysis of a randomised controlled trial. Bone Joint Res 2017;6:631–639. DOI: 10.1302/2046-3758.611.BJR-2017-0060.R1.

Robotic-Arm-Assisted vs Conventional Unicompartmental Knee Arthroplasty. The 2-Year Clinical Outcomes of a Randomized Controlled Trial

BACKGROUND

Unicompartmental knee arthroplasty (UKA) for treatment of medial compartment osteoarthritis has potential benefits over total knee arthroplasty but UKA has a higher revision rate. Robotic-assisted UKA is increasingly common and offers more accurate implant positioning and limb alignment, lower early postoperative pain but evidence of functional outcome is lacking. The aim was to assess the clinical outcomes of a single-centre, prospective, randomised controlled trial, comparing robotic-arm-assisted UKA with conventional surgery.

METHODS

A total of 139 participants were recruited and underwent robotic-arm-assisted (fixed bearing) or conventional (mobile bearing) UKA. Fifty-eight patients in the robotic-arm-assisted group and 54 in the manual group at 2 years. The main outcome measures were the Oxford Knee Score, American Knee Society Score and revision rate.

RESULTS

At 2 years, there were no significant differences for any of the outcome measures. Sub-group analysis (n = 35) of participants with a preoperative University of California Los Angeles Activity Scale >5 (more active) was performed. In this sub-group, the median Oxford Knee Score at 2 years was 46 (IQR 42.0-48.0) for robotic-arm-assisted and 41 (IQR 38.5-44.0) for the manual group (P = .036). The median American Knee Society Score was 193.5 (IQR 184.0-198.0) for the robotic-arm-assisted group and 174.0 (IQR 166.0-188.5) for the manual group (P = .017). Survivorship was 100% in robotic-arm-assisted group and 96.3% in the manual group.

CONCLUSION

Overall, participants achieved an outcome equivalent to the most widely implanted UKA in the United Kingdom. Sub-group analysis suggests that more active patients may benefit from robotic-arm- assisted surgery. Long term follow-up is required to evaluate differences in survivorship.

Anterior cruciate ligament repair with internal brace augmentation: A systematic review

BACKGROUND

Primary repair of anterior cruciate ligament (ACL) ruptures has re-emerged as a treatment option for proximal tears, with internal brace augmentation often utilised. The aim of this study is to provide an overview of the current evidence presenting outcomes of ACL repair with internal bracing to assess the safety and efficacy of this technique.

METHODS

All studies reporting outcomes of arthroscopic primary repair of proximal ACL tears, augmented with internal bracing from 2014-2021 were included. Primary outcome was failure rate and secondary outcomes were subjective patient reported outcome measures (PROMs) and objective assessment of anteroposterior knee laxity.

RESULTS

Nine studies were included, consisting of 347 patients, mean age 32.5 years, mean minimum follow up 2 years. There were 36 failures (10.4%, CI 7.4% - 14.1%). PROMs reporting was variable across studies. KOOS, Lysholm and IKDC scores were most frequently used with mean scores > 87%. The mean Tegner and Marx scores at follow-up were 6.1 and 7.8 respectively. The mean side to side difference measured for anteroposterior knee laxity was 1.2mm.

CONCLUSIONS

This systematic review with meta-analysis shows that ACL repair with internal bracing is a safe technique for treatment of proximal ruptures, with a failure rate of 10.4%. Subjective scores and clinical laxity testing also revealed satisfactory results. This suggests that ACL repair with internal bracing should be considered as an alternative to ACL reconstruction for acute proximal tears, with the potential benefits of retained native tissue and proprioception, as well as negating the need for graft harvest.

Robotic arm-assisted bi-unicompartmental knee arthroplasty maintains natural knee joint anatomy compared with total knee arthroplasty: a prospective randomized controlled trial

AIMS

The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery.

METHODS

An analysis of 38 patients who underwent TKA and 32 who underwent bi-UKA was performed as a secondary study from a prospective, single-centre, randomized controlled trial. CT imaging was used to measure coronal, sagittal, and axial alignment of the knee preoperatively and at three months postoperatively to determine changes in anatomy that had occurred as a result of the surgery. The hip-knee-ankle angle (HKAA) was also measured to identify any differences between the two groups.

RESULTS

The pre- to postoperative changes in joint anatomy were significantly less in patients undergoing bi-UKA in all three planes in both the femur and tibia, except for femoral sagittal component orientation in which there was no difference. Overall, for the six parameters of alignment (three femoral and three tibial), 47% of bi-UKAs and 24% TKAs had a change of < 2° (p = 0.045). The change in HKAA towards neutral in varus and valgus knees was significantly less in patients undergoing bi-UKA compared with those undergoing TKA (p < 0.001). Alignment was neutral in those undergoing TKA (mean 179.5° (SD 3.2°)) while those undergoing bi-UKA had mild residual varus or valgus alignment (mean 177.8° (SD 3.4°)) (p < 0.001).

CONCLUSION

Robotic-assisted, cruciate-sparing bi-UKA maintains the natural anatomy of the knee in the coronal, sagittal, and axial planes better, and may therefore preserve normal joint kinematics, compared with a mechanically aligned TKA. This includes preservation of coronal joint line obliquity. HKAA alignment was corrected towards neutral significantly less in patients undergoing bi-UKA, which may represent restoration of the pre-disease constitutional alignment (p < 0.001). Cite this article: Bone Joint J 2020;102-B(11):1511-1518.

Early outcomes after robotic arm-assisted bi-unicompartmental knee arthroplasty compared with total knee arthroplasty: a prospective, randomized controlled trial

AIMS

The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively.

METHODS

A per protocol analysis of 76 patients, 43 of whom underwent TKA and 34 of whom underwent bi-UKA, was performed from a prospective, single-centre, randomized controlled trial. Diaries kept by the patients recorded pain, function, and the use of analgesics daily throughout the first week and weekly between the second and sixth weeks. Patient-reported outcome measures (PROMs) were compared preoperatively, and at three months and one year postoperatively. Data were also compared longitudinally and a subgroup analysis was conducted, stratified by preoperative PROM status.

RESULTS

Both operations were shown to offer comparable outcomes, with no significant differences between the groups across all timepoints and outcome measures. Both groups also had similarly low rates of complications. Subgroup analysis for preoperative psychological state, activity levels, and BMI showed no difference in outcomes between the two groups.

CONCLUSION

Robotic arm-assisted, cruciate-sparing bi-UKA offered similar early clinical outcomes and rates of complications to a mechanically aligned TKA, both in the immediate postoperative period and up to one year following surgery. Further work is required to identify which patients with osteoarthritis of the knee will derive benefit from a cruciate-sparing bi-UKA. Cite this article: Bone Joint J 2021;103-B(10):1561-1570.

Are there functional biomechanical differences in robotic arm-assisted bi-unicompartmental knee arthroplasty compared with conventional total knee arthroplasty? A prospective, randomized controlled trial

AIMS

The aim of this study was to compare any differences in the primary outcome (biphasic flexion knee moment during gait) of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) at one year post-surgery.

METHODS

A total of 76 patients (34 bi-UKA and 42 TKA patients) were analyzed in a prospective, single-centre, randomized controlled trial. Flat ground shod gait analysis was performed preoperatively and one year postoperatively. Knee flexion moment was calculated from motion capture markers and force plates. The same setup determined proprioception outcomes during a joint position sense test and one-leg standing. Surgery allocation, surgeon, and secondary outcomes were analyzed for prediction of the primary outcome from a binary regression model.

RESULTS

Both interventions were shown to be effective treatment options, with no significant differences shown between interventions for the primary outcome of this study (18/35 (51.4%) biphasic TKA patients vs 20/31 (64.5%) biphasic bi-UKA patients; p = 0.558). All outcomes were compared to an age-matched, healthy cohort that outperformed both groups, indicating residual deficits exists following surgery. Logistic regression analysis of primary outcome with secondary outcomes indicated that the most significant predictor of postoperative biphasic knee moments was preoperative knee moment profile and trochlear degradation (Outerbridge) (R² = 0.381; p = 0.002, p = 0.046). A separate regression of alignment against primary outcome indicated significant bi-UKA femoral and tibial axial alignment (R² = 0.352; p = 0.029), and TKA femoral sagittal alignment (R² = 0.252; p = 0.016). The bi-UKA group showed a significant increased ability in the proprioceptive joint position test, but no difference was found in more dynamic testing of proprioception.

CONCLUSION

Robotic arm-assisted bi-UKA demonstrated equivalence to TKA in achieving a biphasic gait pattern after surgery for osteoarthritis of the knee. Both treatments are successful at improving gait, but both leave the patients with a functional limitation that is not present in healthy age-matched controls. Cite this article: Bone Joint J 2022;103-B(4):433-443.

Evaluating the diagnostic pathway for acute ACL injuries in trauma centres: a systematic review

Objective

This review sought to evaluate the literature on the initial assessment and diagnostic pathway for patients with a suspected Anterior Cruciate Ligament (ACL) tear.

Methods

MEDLINE, EMBASE, and CINAHL were systematically searched for eligible studies, PRISMA guidelines were followed. Studies were included if they used at least one assessment method to assess for ACL injury and participants were assessed at an acute trauma centre within 6-weeks of injury. Article quality was evaluated using the QUADAS-2 checklist.

Results

A total of 353 studies were assessed for eligibility, 347 were excluded for the following reasons: injuries were not assessed in an acute trauma setting, injuries were not acute, participants had previous ACL injuries or chronic joint deformities affecting the knee, participants were under 18, or participants included animals or cadavers. A total of six studies were included in the review. Common assessment methods included: laxity tests, joint effusion, inability to continue activity, and a history of a ‘pop’ and ‘giving way’ at the time of injury. Diagnostic accuracy varied greatly between the assessment method and the assessing clinician. Gold standard diagnostics were MRI and arthroscopy. A weighted meta-mean calculated the time to reach diagnosis to be 68.60 days [CI 23.94, 113.24]. The mean number of appointments to reach diagnosis varied from 2–5. Delay to surgery or surgical consultation ranged from 61 to 328 days.

Conclusion

Clinicians in the Emergency Department are not proficient in performing the assessment methods that are used for diagnosis in acute ACL injury. Reliance on specialist assessments or radiological methods inevitably increases the time to reach a diagnosis, which has repercussions on management options. There is an ever-growing demand to improve diagnostic accuracy and efficiency; further exploration into quantitative measures of instability would aid the assessment of peripheral joint assessment.

Deficits in muscle strength are not seen following recovery from augmented primary repair of anterior cruciate ligament tears

OBJECTIVES

Anterior cruciate ligament (ACL) repair for proximal tears, where the ligament is re-attached and augmented with suture tape, can negate the need for graft harvest, thereby maintaining native anatomy. Autograft harvest has been associated with persistent deficits in lower limb muscle strength after recovery from ACL reconstruction. The aim of this study is to compare lower limb muscle strength following ACL repair and reconstruction.

METHODS

Nineteen ACL repair patients augmented with suture tape and nineteen ipsilateral semitendinosus-gracilis autograft ACL reconstruction patients (both mean 4 years postoperatively) were recruited, along with twenty healthy volunteers. Patient-reported outcome measures (PROMs) were obtained using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm, and Tegner scores. Maximal isometric quadriceps and hamstring strength at 90° knee flexion were measured using a fixed Myometer after a warm-up and three maximal-effort contractions.

RESULTS

Mean hamstring strength of the reconstructed legs was lower than that of healthy volunteers by 0.29 Nm/kg. The hamstring strength ratio of the operated side to the uninjured side was greater in the repair (95% ​± ​13) than in the reconstruction (81% ​± ​18) group. There were no statistically significant differences between sides for quadriceps peak torque or for hamstrings in the volunteer or repair group. PROMs scores for the reconstruction group were significantly lower than volunteers across all domains and lower than repair for KOOS activities of daily living and Lysholm scores.

CONCLUSION

Hamstring weakness seen following ACL reconstruction is not evident following ACL repair with suture tape augmentation. Strength asymmetry could contribute to re-injury risk and influence functional performance, while altered loads affect knee biomechanics and may lead to osteoarthritis progression. The absence of these deficits in the repair group demonstrates a potential benefit of this technique when used in appropriate patients.

LEVEL OF EVIDENCE

II.