Introduction

While manual total knee arthroplasty (MTKA) procedures have demonstrated excellent clinical success, occasionally intraoperative damage to soft tissues can occur. Robotic-arm assisted technology is designed to constrain a sawblade in a haptic zone to help ensure that only the desired bone cuts are made. The objective of this cadaver study was to quantify the extent of soft tissue damage sustained during TKA through a robotic-arm assisted (RATKA) haptically guided approach and conventional MTKA approach.

I never considered this to be a significant problem if it is noticed. (back to that later)

Aaron Rosenberg's report seems to have agreed, but at the last members meeting of the Knee Society, Boston, September 2009, others had experience that contradicted my view.

With their experience, ultimately the results were very substantially compromised. This video and presentation show you how to avoid a bad result, actually obtain a perfect result, if you or your student assistant, resident or fellow, bags the MCL.

There are three important points. (1) One needs to recognise the occurrence. (2) The setting is usually varus and so direct end-to-end repair cannot be depended upon. (3) Use of a semitendinosis tenodesis, together with an imperfect, distracted direct repair works perfectly well!

(1) Recognition: The setting is usually varus, but I have had one case in which the chief resident, working with the fellow succeeded in getting the MCL in a valgus knee! In this usually tight varus setting the key feature is that at some point in the case, before component placement, one notices that the exposure is all of a sudden better! Now, the guilty resident or just a passive assisting resident/fellow will usually disagree. The extension space is not so obviously lax, but the flexion space is. Secondly, you do not feel an intact ligament in flexion. And, to prove it I have had to do a little more exposure of the superficial MCL to show the tear. There are at least three mechanisms. Most common is a saw cut. Next is possibly injury with the scalpel or cutting cautery during exposure, and last is damage essentially pre-operatively by a very sharp medial osteophyte which has thoroughly abraded the ligament.

Laxity in full flexion is not necessarily obvious as the posterior capsular integrity helps hide the instability. Again, the really intact ligament is well felt, and in the situation of laceration, the tibia pulls forward more on the medial side, the medial flexion space opens, and what was usually a tight exposure gets suddenly better.

(2) When varus is the setting, I have found it impossible or at least uncomfortable to depend upon direct repair. When the soft tissues are needing to be released or simply undergoing more stress than usual and a lot more than on the lateral side, I see it as unwise to expect or depend upon only a medial repair to hold.

(3) The semitendinosis tenodesis has worked essentially perfectly in every one of my cases. These patients have had no post-operative instability and they have had better than average to extremely good ROM.

A presumably key point is not to alter the patient's post-operative regimen! And, to avoid some passive alteration of PT, I advise specifically that the surgeon or those in his/her team do not mention the occurrence to the patient, the family or the PT! I put the whole story in the op-note, and weeks later I will specifically tell the patient what the staple in place is all about.

I never considered this to be a significant problem if it is noticed. (back to that later)

Aaron Rosenberg's report seems to have agreed, but at the last members' meeting of the Knee Society, Boston, September 2009, others had experience that contradicted my view.

With some experience, ultimately the results were very substantially compromised. This video and presentation show you how to avoid a bad result, actually obtain a perfect result, if you or your student assistant, resident or fellow, bags the MCL.

There are three important points. (1) One needs to recognise the occurrence. (2) The setting is usually varus and so direct end-to-end repair cannot be depended upon. (3) Use of a semitendinosis tenodesis, together with an imperfect, distracted direct repair works perfectly well! (1)

Recognition: The setting is usually varus, but I have had one case in which the chief resident, working with the fellow succeeded in getting the MCL in a valgus knee! In this usually tight varus setting the key feature is that at some point in the case, before component placement, one notices that the exposure is all of a sudden better! Now, the guilty resident or just a passive assisting resident/fellow will usually disagree. The extension space is not so obviously lax, but the flexion space is. Secondly, you do not feel an intact ligament in flexion. And, to prove it I have had to do a little more exposure of the superficial MCL to show the tear. There are at least three mechanisms. Most common is a saw cut. Next is possibly injury with the scalpel or cutting cautery during exposure, and last is damage essentially pre-op by a very sharp medial osteophyte which has thoroughly abraded the ligament.

Laxity in full flexion is not necessarily obvious as the posterior capsular integrity helps hide the instability. Again, the really intact ligament is well felt, and in the situation of laceration, the tibia pulls forward more on the medial side, the medial flexion space opens, and what was usually a tight exposure gets suddenly better.

A presumably key point is not to alter the patient's post-operative regimen! And, to avoid some passive alteration of PT, I advise specifically that the surgeon or those in his/her team do not mention the occurrence to the patient, the family or the PT! I put the whole story in the op-note, and weeks later I will specifically tell the patient what the staple in place is all about.

Knee arthroscopy is typically approached from the anterior, posteromedial and posterolateral portals. Access to the posterior compartments through these portals can cause iatrogenic cartilage damage and create difficulties in viewing the structures of the posterior compartments. The purpose of this study was to assess the feasibility of needle arthroscopy using direct posterior portals as both working and visualising portals. For workability, the needle scope was inserted advanced from anterior between the cruciate ligament bundle and the lateral wall of the medial femoral condyle until the posterior compartments were visualised. For visualisation, direct postero-lateral and -medial portals were established. The technique was performed in 9 knees by two experienced researchers. Workability and instrumentation of the posteromedial compartment and meniscus was achieved in 56%. The posterior horns could not be visualised in four specimens as the straight lens could not provide a more medial field of view. Visualisation from the direct medial posterior portal allowed a clear view of the medial meniscus, femoral condyle and posterior cruciate ligament in all specimens. Workability and instrumentation of the posterolateral compartment was not possible with the needle scope. Direct posterior approaches for the posteromedial compartment access are challenging with the current needle scope options and could only be achieved in over 50%. The postero-lateral compartment was not accessible. An angled lens or a flexible Needle scope would be better suited for developing this technique further

Introduction. Robot systems have been successfully introduced to improve the accuracy and reduce severe iatrogenic soft tissue damage in knee arthroplasty. Unfortunately to perform complete a complete bone cut, the cutting tool has to slightly pass the edge of the bone. In the posterior zones were retractor protection is impossible this will lead to contact between the cutting tool and the soft tissue envelope. Therefore, complete soft tissue preservation cannot be guaranteed with the current commercial systems. Methods. This study presents an alternative robotic controlled cutting technique to perform the bone resections during TKA by milling a slot with a long slender high-speed milling tool. The system is composed by a long milling tool driven by a high-speed motor and a protector covering the end of the cutter. The protector is rigidly connected to the motor by the support structure next to the mill, which moves behind the mill in the slot created by the cutter. The protector at the end of the cutter has four functions: providing mechanical support for the mill, preventing soft tissue to come into contact with the cutter, sensing the edge of the bone to accurately follow the shape of the bone and releasing the attached soft tissue. The edge of the bone is sensed by force feedback and with the help of a probing motion the adaptive algorithm enables the protector to follow the edge of the bone closely by compensating for small segmentation and registration errors. A pilot test to evaluate the concept was performed on three fresh frozen knees. The flatness of the resection, the iatrogenic soft tissue damage, the cutting time and the efficiency of the bone contour following algorithm was measured. Results. An Rq flatness of 0.10±0.03 mm and the Rt flatness of 0.52±0.08 was obtained. The MASTI score for soft tissue damage was 34.11±1.0 resulting in two A scores and one B score. The active contour following algorithm was capable of predicting the physical location of the bone three times more accurate compared to the initial surface based registration (1.51±0.31 mm to 0.44±0.29 mm). The cutting time was 106±7 s. Discussion. The mean flatness was about three times better compared to the oscillating saw and in line with other active robots using a mill. In contrast to other orthopaedic robotic systems with a rotating cutter, this technique enables performing each resection in TKA in one movement. Therefore the new approach was significantly faster compared to other active robotic systems using a mill. Because of the active shielding of the cutter, only very little superficial soft tissue was observed. Furthermore, the adaptive bone contour approach opens the possibility for imageless active robotic knee arthroplasty. Conclusion. The promising results of this pilot study demonstrate the potential of the novel soft tissue protecting cutter by combining the accuracy of a cylindrical mill with an active soft tissue protection while reducing the cutting time

Recent literature has demonstrated that conventional arthroscopic techniques do not adequately visualise areas of predilection of pathology of the long head of biceps (LHB) tendon and are associated with a 30–50% rate of missed diagnoses. The aim of this study was to evaluate the safety, effectiveness and ease of performing biceps tenoscopy as a novel strategy for reducing the rate of missed diagnoses. Five forequarter amputation cadaver specimens were studied. The pressure in the anterior compartment was measured before and after surgical evaluation. Diagnostic glenohumeral arthroscopy was performed and the biceps tendon was tagged to mark the maximum length visualised by pulling the tendon into the joint. Biceps tenoscopy was performed using 3 different techniques (1. Flexible video-endoscopy, 2. Standard arthroscopy via Neviaser portal. 3. Standard arthroscope via antero-superior portal with retrograde instrumentation). Each was assessed for safety, ease of the procedure and whether the full length of the extra-articular part of the LHB tendon could be visualised. The t-test was used to compare the length of the LHB tendon visualised at standard glenohumeral arthroscopy vs that visualised at biceps tenoscopy. An open dissection was performed after the arthroscopic procedures to evaluate for an iatrogenic injury to local structures. Biceps tenoscopy allowed visualisation to the musculotendinous junction in all cases. The mean length of the tendon visualised was therefore significantly greater at biceps tenoscopy (104 mm) than at standard glenohumeral arthroscopy (33 mm) (mean difference 71 mm, p<0.0001). Biceps tenoscopy was safe with regards to compartment syndrome and there was no difference between pre- and post-operative pressure measurements (mean difference 0 mmHg, p=1). No iatrogenic injuries were identified at open dissection. Biceps tenoscopy allows excellent visualisation of the entire length of the LHB tendon and therefore has the potential to reduce the rate of missed diagnoses. This study did not demonstrate any risk of iatrogenic injury to important local structures or any risk of compartment syndrome. Clinical evaluation is required to further validate this technique

Closed reduction and percutaneous pinning has become the most common technique for the treatment of Type III displaced supracondylar humerus fractures in children. The purpose of this study was to evaluate whether the loss of reduction in lateral K wiring is non-inferior to crossed K wiring in this procedure. A prospective randomised non-inferiority trial was conducted. Patients aged three to seven presenting to the Emergency Department with a diagnosis of Type III supracondylar humerus fracture were eligible for inclusion in the study. Consenting patients were block randomised into one of two groups based on wire configuration (lateral or crossed K wires). Surgical technique and post-operative management were standardised between the two groups. The primary outcome was loss of reduction, measured by the change in Baumann's angle immediately post –operation compared to that at the time of K wire removal at three weeks. Secondary outcome data collected included Flynn's elbow score, the humero-capitellar angle, and evidence of iatrogenic ulnar nerve injury. Data was analysed using a t-test for independent means. A total of 52 patients were enrolled at baseline with 23 allocated to the lateral pinning group (44%) and 29 to the cross pinning group (56%). Six patients (5 crossed, 1 lateral) received a third wire and one patient (crossed) did not return for x-rays at pin removal and were therefore excluded from analysis. A total of 45 patients were subsequently analysed (22 lateral and 23 crossed). The mean change in Baumann's angle was 1.05 degrees, 95% CI [-0.29, 2.38] for the lateral group and 0.13 degrees, 95% CI [-1.30, 1.56] for the crossed group. There was no significant difference between the groups in change in Baumann's Angle at the time of pin removal (p = 0.18). Two patients in the crossed group developed post-operative iatrogenic ulnar nerve injuries, while none were reported in the lateral group. Preliminary analysis shows that loss of reduction in Baumann's angle with lateral K wires is not inferior to crossed K wires in the management of Type III supracondylar humerus fractures in children. The results of this study suggest that orthopaedic surgeons who currently use crossed K wires could consider switching to lateral K wires in order to reduce the risk of iatrogenic ulnar nerve injuries without significantly compromising reduction

Hip arthroscopy rates continue to increase. As a result, there is growing interest in capsular management techniques. Without careful preservation and surgical techniques, failure of the repair result in capsular deficiency, contributing to iatrogenic instability and persistent post-operative pain. In this setting, capsular reconstruction may be indicated, however there is a paucity of objective evidence comparing surgical techniques to identify the optimal method. Therefore, the objective of this study was to evaluate the biomechanical effect of capsulectomy and two different capsular reconstruction techniques (iliotibial band [ITB] autograft and Achilles tendon allograft) on hip joint kinematics in both rotation and abduction/adduction. Eight paired fresh-frozen hemi-pelvises were dissected of all overlying soft tissue, with the exception of the hip joint capsule. The femur was potted and attached to a load cell connected to a joint-motion simulator, while the pelvis was secured to a custom-designed fixture allowing adjustment of the flexion-extension arc. Optotrak markers were rigidly attached to the femur and pelvis to track motion of the femoral head with respect to the acetabulum. Pairs were divided into ITB or Achilles capsular reconstruction. After specimen preparation, three conditions were tested: (1) intact, (2) after capsulectomy, and (3) capsular reconstruction (ITB or Achilles). All conditions were tested in 0°, 45°, and 90° of flexion. Internal rotation (IR) and external rotation (ER) as well abduction (ABD) and adduction (ADD) moments of 3 N·m were applied to the femur via the load cell at each position. Rotational range of motion and joint kinematics were recorded. When a rotational force was applied the total magnitude of internal/external rotation was significantly affected by the condition of the capsule, independent of the type of reconstruction that was performed (p=0.001). The internal/external rotation increased significantly by approximately 8° following the capsulectomy (p<0.001) and this was not resolved by either of the reconstructions; there remained a significant difference between the intact and reconstruction conditions (p=0.035). The total anterior/posterior translation was significantly affected by the condition of the capsule (p=0.034). There was a significant increase from 6.7 (6.0) mm when the capsule was intact to 9.0 (6.7) mm following the capsulectomy (p=0.002). Both of the reconstructions (8.6 [5.6] mm) reduced the anterior/posterior translation closer to the intact state. There was no difference between the two reconstructions. When an abduction/adduction force was applied there was a significant increase in the medial-lateral translation between the intact and capsulectomy states (p=0.047). Across all three flexion angles the integrity of the native hip capsule played a significant role in rotational stability, where capsulectomy significantly increased rotational ROM. Hip capsule reconstruction did not restore rotational stability and also increased rotational ROM compared to the intact state a statistically significant amount. However, hip capsule reconstruction restored coronal and sagittal plane stability to approach that of the native hip. There was no difference in stability between ITB and Achilles reconstructions across all testing conditions

Controversy remains regarding the optimal treatment for iatrogenic injury to the medial collateral ligament (MCL) during primary total knee arthroplasty (TKA). Some authors have recommended converting to a prosthesis that provides varus/valgus constraint while others have recommended primary repair. In this study we report the results of a 45 patients who sustained intra-operative MCL injuries during primary TKA that were treated with primary repair. Of 3922 consecutive primary TKA there were 48 (1.2%) intra-operative MCL lacerations or avulsions. One patient was lost and one died before 24-month follow-up. All but one patient underwent primary repair with placement of components without varus/valgus constraint. This left 45 knees with a mean follow up of 89 months (range, 24 – 214 months). The mean HSS knee scores increased from 47 to 85 points (p<0.001). No patients had subjective complaints of instability. No patients had excessive varus/valgus laxity when tested in full extension and 30 degrees of flexion. The range of motion at the time of final follow-up averaged 110 degrees (range, 85 – 130 degrees). Five knees required treatment for stiffness with 4 knees undergoing manipulation under anesthesia and 1 knee undergoing open lysis of adhesions with polyethylene articular surface exchange. Two knees underwent revision for aseptic loosening of the tibial component. In the three knees that underwent open revision, the MCL was noted to be in continuity and without laxity. Primary repair with 6 weeks of post-operative hinged bracing after iatrogenic injury to the MCL during primary TKA was successful at preventing instability although stiffness was seen in approximately 10% of patients. The increased morbidity associated with implantation of a semi-constrained or constrained implant may be unwarranted in this situation

Introduction. Treatment for distal third shaft fractures of humerus is very challenging. They are commonly treated with plating. Plating has complications of iatrogenic radial nerve palsy. We report our case series of distal third fractures of humerus treated with retrograde Halder Humeral Nail. Materials/Methods. Since 1994 to 2010 we have 576 fractures of humerus treated with retrograde Halder Humeral nail. Of these 45 fractures were distal third of humerus. Average age of patients at the time of surgery was 30.4 years (Range 15–82 years, Median 33 years). Of 45 patients 26 were females and 19 males. Three out of 45 had non union at the time of presentation. All patients were followed until clinical and radiological signs of union. One patient was lost to follow-up. Results. Average time to fracture healing was 13.9 weeks (Range 9–36 weeks). There were two cases of non union, one healed at 9 months with 2. nd. surgery. There was one reported case of infection. Seven patients had nail removal electively. All the patients achieved full range of elbow and shoulder movement. No reported cases of iatrogenic radial nerve palsy. Conclusion. Our results of distal third fractures of humerus treated with retrograde Halder Humeral Nail are excellent. It avoids big exposure as needed in plating and complication of iatrogenic radial nerve palsy

Objective:. To observe the incidence of intra-operative vascular injuries during anterior cervical decompression and fusion (ACDF). Secondly, management and monitoring of the outcome post vascular injury during ACDF. Methods:. This a prospective study. A review of all spinal patients' records was performed from June 2006 to April 2011. A comprehensive literature review was also utilized. Inclusion criteria – all patients had ACDF post trauma. All non-traumatic cases were excluded. Results:. The study consisted of 55 patients; 15 were females and 40 were males. The age distribution was 23–65 years. Two patients were excluded due to non-traumatic causes. Of the remaining 53 patients, four sustained intra-operative vascular injuries during ACDF surgery. All 4 patients had corpectomies, and one case was an iatrogenic injury. The commonly injured vessel during the ACDF surgery was the left vertebral artery. Haemostatic control was achieved via tamponade and haemostatic agents. The left common carotid was iatrogenically injured in one case and was treated by microvascular repair. Three patients were treated with antiplatelet therapy for three months duration. The patient with an iatrogenic injury was treated with anticoagulation therapy for three months duration. All computerized tomographic angiograms at three months follow up illustrated patent vessels. Conclusion:. There is an increased incidence of intra operative vascular injuries during ACDF associated with corpectomies. It is essential to be aware of the low incidence of intra operative arterial injury during ACDF and to have a management approach, such as tamponade or microvascular repair. Anticoagulation and antiplatelet therapy is effective in decreasing the complications of vascular injuries post ACDF

Aim. Treatment for distal third shaft fractures of humerus is very challenging especially if its comminuted and bone is osteopenic. They are commonly treated with plating. Plating has complications of iatrogenic radial nerve palsy. We report our case series of distal third fractures of humerus treated with retrograde Halder Humeral Nail. Materials and methods. Since 1994 to 2010 we have 576 fractures of humerus treated with retrograde Halder Humeral nail. Of these 45 were distal third extra articular fractures of humerus. Average age of patients at the time of surgery was 30.4 years (Range 15–82 years, Median 33 years). Of 45 patients 26 were females and 19 males.3 out of 45 had non union at the time of presentation. The nail was locked distally with one or two screws and proximally with a screw and tripwire. The entry point of the nail was roof of olecranon fossa (contrary to standard retrograde nails where it is an inch above olecranon fossa) This design of nail allows it be used for even very distal fractures. All patients were followed till clinical and radiological signs of union. 1 patient was lost to follow up. Results. Average time to fracture healing was 13.9 weeks (Range 9–36 weeks). There were 2 cases of non union, one healed at 9 months with 2. nd. surgery. The other non union was asymptomatic and did not agree for further surgery. There was one reported case of infection.7 patients had nail removal electively on request. All the patients achieved full range of elbow and shoulder movement. No reported cases of iatrogenic radial nerve palsy. Conclusion. Our results of distal third fractures of humerus treated with retrograde Halder Humeral Nail are excellent. It avoids big exposure as needed in plating and complication of iatrogenic radial nerve palsy

Controversy remains regarding the optimal treatment for iatrogenic injury to the medial collateral ligament (MCL) during primary total knee arthroplasty (TKA). Some authors have recommended converting to a prosthesis that provides varus/valgus constraint while others have recommended primary repair. In this study, we report the results of 45 patients who sustained intra-operative MCL injuries during primary TKA that were treated with primary repair. Of 3922 consecutive primary TKA there were 48 (1.2%) intra-operative MCL lacerations or avulsions. One patient was lost and one died before 24 months follow up. All but one patient underwent primary repair with placement of components without varus/valgus constraint. This left 45 knees with a mean follow up of 89 months (range, 24 to 214 months). The mean HSS knee scores increased from 47 to 85 points (p<0.001). No patients had subjective complaints of instability. No patients had excessive varus/valgus laxity when tested in full extension and 30 degrees of flexion. The range of motion at the time of final follow-up averaged 110 degrees (range, 85 to 130 degrees). Five knees required treatment for stiffness with 4 knees undergoing manipulation under anaesthesia and 1 knee undergoing open lysis of adhesions with polyethylene articular surface exchange. Two knees underwent revision for aseptic loosening of the tibial component. In the three knees that underwent open revision, the MCL was noted to be in continuity and without laxity. Primary repair with 6 weeks of post-operative hinged bracing after iatrogenic injury to the MCL during primary TKA was successful at preventing instability although stiffness was seen in approximately 10% of patients. The increased morbidity associated with implantation of a semi-constrained or constrained implant may be unwarranted in this situation

With the success of the medial parapatellar approach (MPA) to total knee arthroplasty (TKA), current research is aimed at reducing iatrogenic microneurovascular and soft tissues damage to the knee. In an effort to avoid disruption to the medial structures of the knee, we propose a novel quadriceps-sparing, subvastus lateralis approach (SLA) to TKA. The aim of the present study is to compare if a SLA can provide adequate exposure of the internal compartment of the knee while reducing soft tissue damage, compared to the MPA. Less disruption of these tissues could translate to better patient outcomes, such as reduced post-operative pain, increased range of motion, reduced instances of patellar maltracking or necrosis, and a shorter recovery time. To determine if adequate exposure could be achieved, the length of the skin incision and perimeter of surgical exposure was compared amongst 22 paired fresh-frozen cadaveric lower limbs (five females/six males) which underwent TKA using the SLA or MPA approach. Additionally, subjective observations which included the percent of visibility of the femoral condyles and tibial plateau, as well as the patellar tracking, were noted in order to qualify adequate exposure. All procedures were conducted by the same surgeon. Subsequently, to determine the extent of soft tissue damage associated with the approaches, an observational assessment of the dynamic and static structures of the knee was performed, in addition to an examination of the microneurovascular structures involved. Dynamic and static structures were assessed by measuring the extent of muscular and ligamentus damage during gross dissection of the internal compartment of the knee. Microneurovascular involvement was evaluated through a microscopic histological examination of the tissue harvested adjacent to the capsular incision. Comparison of the mean exposure perimeter and length of incision was not significantly different between the SLA and the MPA (p>0.05). In fact, on average, the SLA facilitated a 5 mm larger exposure perimeter to the internal compartment, with an 8 mm smaller incision, compared to the MPA, additional investigation is required to assert the clinical implications of these findings. Preliminary analysis of the total visibility of the femoral condyles were comparable between the SLA and MPA, though the tibial plateau visibility appears slightly reduced in the SLA. Analyses of differences in soft tissue damage are in progress. Adequate exposure to the internal compartment of the knee can be achieved using an incision of similar length when the SLA to TKA is performed, compared to the standard MPA. Future studies should evaluate the versatility of the SLA through an examination of specimens with a known degree of knee deformity (valgus or varus)

Surgical management of cam-type femoroacetabular impingement (FAI) aims to preserve the native hip, restore joint function, and delay the onset of osteoarthritis. However, it is unclear how surgery affects joint mechanics and hip joint stability. The aim was to examine the contributions of each surgical stage (i.e., intact cam hip, capsulotomy, cam resection, capsular repair) towards hip joint centre of rotation and microinstability. Twelve fresh, frozen cadaveric hips (n = 12 males, age = 44 ± 9 years, BMI = 23 ± 3 kg/m2) were skeletonized to the capsule and included in this study. All hips indicated cam morphology on CT data (axial α = 63 ± 6°, radial α = 74 ± 4°) and were mounted onto a six-DOF industrial robot (TX90, Stäubli). The robot positioned each hip in four sagittal angles: 1) Extension, 2) Neutral 0°, 3) Flexion 30°, and 4) Flexion 90°, and performed internal and external hip rotations until a 5-Nm torque was reached in each direction, while recording the hip joint centre's neutral path of translation. After the (i) intact hip was tested, each hip underwent a series of surgical stages and was retested after each stage: (ii) T-capsulotomy (incised lateral iliofemoral capsular ligament), (iii) cam resection (removed morphology), and (iv) capsular repair (sutured portal incisions). Eccentricity of the hip joint centre was quantified by the microinstability index (MI = difference in rotational foci / femoral head radius). Repeated measures ANOVA and post-hoc paired t-tests compared the within-subject differences in hip joint centre and microinstability index, between the testing stages (CI = 95%, SPSS v.24, IBM). At the Extension and Neutral positions, the hip joint centre rotated concentrically after each surgical stage. At Flexion 30°, the hip joint centre shifted inferolaterally during external rotation after capsulotomy (p = 0.009), while at Flexion 90°, the hip joint centre further shifted inferolaterally during external rotation (p = 0.005) and slightly medially during internal rotation after cam resection, compared to the intact stages. Consequently, microinstability increased after the capsulotomy at Flexion 30° (MI = +0.05, p = 0.003) and substantially after cam resection at Flexion 90° (MI = +0.07, p = 0.007). Capsular repair was able to slightly restrain the rotational centre and decrease microinstability at the Flexion 30° and 90° positions (MI = −0.03 and −0.04, respectively). Hip microinstability occurred at higher amplitudes of flexion, with the cam resection providing more intracapsular volume and further lateralizing the hip joint during external rotation. Removing the cam deformity and impingement with the chondrolabral junction also medialized the hip during internal rotation, which can restore more favourable joint loading mechanics and stability. These findings support the pathomechanics of cam FAI and suggest that iatrogenic microinstability may be due to excessive motions, prior to post-operative restoration of static (capsular) and dynamic (muscle) stability. In efforts to limit microinstability, proper nonsurgical management and rehabilitation are essential, while activities that involve larger amplitudes of hip flexion and external rotation should be avoided immediately after surgery

Controversy remains regarding the optimal treatment for iatrogenic injury to the medial collateral ligament (MCL) during primary total knee arthroplasty (TKA). Some authors have recommended converting to a prosthesis that provides varus/valgus constraint while others have recommended primary repair. In this study we report the results of a 45 patients who sustained intraoperative MCL injuries during primary TKA that were treated with primary repair. Of 3922 consecutive primary TKA there were 48 (1.2%) intraoperative MCL lacerations or avulsions. One patient was lost and one died before 24 months follow up. All but one patient underwent primary repair with placement of components without varus/valgus constraint. This left 45 knees with a mean follow up of 89 months (range, 24–200). The mean HSS knee scores increased from 46.8 to 84.8 points (p<0.001). No patients had subjective complaints of instability. No patients had excessive varus/valgus laxity when tested in full extension and 30 degrees of flexion. The range of motion at the time of final follow-up averaged 110 degrees (range, 85 degrees to 130 degrees). Five knees required treatment for stiffness with 4 knees undergoing manipulation under anesthesia and 1 knee undergoing open lysis of adhesions with polyethylene articular surface exchange. Two knees underwent revision for aseptic loosening of the tibial component. In the three knees that underwent open revision, the MCL was noted to be in continuity and without laxity. Primary repair with 6 weeks of postoperative hinged bracing after iatrogenic injury to the MCL during primary TKA was successful at preventing instability although stiffness was seen in approximately 10% of patients. The increased morbidity associated with implantation of a semiconstrained or constrained implant may be unwarranted in this situation

Introduction. Studies have shown that dissatisfaction following TKA may stem from poor component placement and iatrogenic factors related to variability in surgical execution. A CT-based robotic assisted system (RA) allows surgeons to dynamically balance the joint prior to bone resection. This study aimed to determine if this system could improve TKA planning, reduce soft tissue releases, minimize bone resection, and accurately predict component size in varus knee. Method. Four hundred and seventy four cases with varus deformity undergoing primary RATKA were enrolled in this prospective, single center and surgeon study. Patient demographics and intraoperative surgical details were collected. Initial and final 3-dimensional alignment, component position, bone resection depths, use of soft tissue releases, knee balancing gaps, and component size were collected intraoperatively. WOMAC and KOOS Jr. scores were collected 6 months, and 1 year postoperatively. Descriptive statistics were applied to determine the changes in these parameters between initial and final values. Results. Native deformity ranged from 1 to 19 degrees of varus. 86% of patients in this study did not require a soft tissue release regardless of their level of coronal or sagittal deformity. Complex deformities who required a soft tissue release were corrected on average to 3 degrees varus while cases without releases were corrected to 2 degrees varus on average with the overall goal as traditional mechanical alignment. All surgeons achieved their planned sizes on the tibia and femur more than 98% of the time within one size, and 100% of the time within two sizes. Flexion and extension gaps during knee balancing were within 2mm (mean 1mm) for all knees. At latest follow-up, radiographic evidence suggested well-seated and well-fixed components. Radiographs also indicated the patella components were tracking well within the trochlear groove. No revision and re-operation were reported. Mean WOMAC total score was improved from 23.8±8.0 pre-op to 8.9±7.9 1-year post-op (p<0.01). Mean KOOS Jr. score was improved from 46.8±11.6 pre-op to 77.9±14.8 1-year post-op (p<0.01). Discussion and Conclusions. New tools may allow for enhanced execution and predictable balance for TKA, which may improve patient outcomes. In this study, preoperative planning via CT scan allowed surgeons to assess bony deformities and subtly adjust component position to reduce soft tissue trauma. While this study has several limitations, RATKA for varus knees should continue to be investigated. For any figures or tables, please contact authors directly

Introduction. Soft tissue releases are often required to correct deformity and achieve gap balance in total knee arthroplasty (TKA). However, the process of releasing soft tissues can be subjective and highly variable and is often perceived as an ‘art’ in TKA surgery. Releasing soft tissues also increases the risk of iatrogenic injury and may be detrimental to the mechanically sensitive afferent nerve fibers which participate in the regulation of knee joint stability. Measured resection TKA approaches typically rely on making bone cuts based off of generic alignment strategies and then releasing soft tissue afterwards to balance gaps. Conversely, gap-balancing techniques allow for pre-emptive adjustment of bone resections to achieve knee balance thereby potentially reducing the amount of ligament releases required. No study to our knowledge has compared the rates of soft tissue release in these two techniques, however. The objective of this study was, therefore, to compare the rates of soft tissue releases required to achieve a balanced knee in tibial-first gap-balancing versus femur-first measured-resection techniques in robotic assisted TKA, and to compare with release rates reported in the literature for conventional, measured resection TKA [1]. Methods. The number and type of soft tissue releases were documented and reviewed in 615 robotic-assisted gap-balancing and 76 robotic-assisted measured-resection TKAs as part of a multicenter study. In the robotic-assisted gap balancing group, a robotic tensioner was inserted into the knee after the tibial resection and the soft tissue envelope was characterized throughout flexion under computer-controlled tension (fig-1). Femoral bone resections were then planned using predictive ligament balance gap profiles throughout the range of motion (fig-2), and executed with a miniature robotic cutting-guide. Soft tissue releases were stratified as a function of the coronal deformity relative to the mechanical axis (varus knees: >1° varus; valgus knees: >1°). Rates of releases were compared between the two groups and to the literature data using the Fischer's exact test. Results. The overall rate of soft tissue release was significantly lower in the robotic gap-balancing group, with 31% of knees requiring one or more releases versus 50% (p=0.001) in the robotic measured resection group and 66% (p<0.001) for conventional measured resection (table-1) [1]. When comparing as a function of coronal deformity, the difference in release rates for robotic gap-balancing was significant when compared to the conventional TKA literature data (p<0.0001) for all deformity categories, but only for varus and valgus deformities for robotic measured resection with the numbers available (varus: 33% vs 50%, p=0.010; neutral 11% vs 50%, p=0.088, valgus 27% vs 53%, p=0.048). Discussion. Robotic-assisted tibial-first gap-balancing techniques allow surgeons to plan and adjust femoral resections to achieve a desired gap balance throughout motion, prior to making any femoral resections. Thus, gap balance can be achieved through adjustment of bone resections, which is accurate to 1mm/degree with robotics, rather than through manual releasing soft tissues which is subjective and less precise. These results demonstrated that the overall rate of soft tissue release is reduced when performing TKA with predictive gap-balancing and a robotic tensioning system. For any figures or tables, please contact authors directly

Aim. Fixation of distal radial fractures via the volar approach has become a commonly performed procedure over the past few years. This study is to highlight potential pitfalls with this ‘everyday’ procedure and to perhaps temper over-enthusiasm for plating all wrist fractures. Method and materials. 164 consecutive cases of wrist fracture treated by means of fixed angle volar fixation were looked at. In each case any recorded complication prior to completion of treatment was documented. The complications were divided into major and minor depending on the severity and long-term outcome and overall result. Results. With critical analysis there were 32 major complications: 12 required further surgery; 1 iatrogenic radial artery injury; 1 iatrogenic palmar branch of median nerve injury; 2 complex regional pain syndromes; 16 patients with less than 60 arc of movement. In addition 12 minor complications including hypertrophic scars, suture abscess and intermittent minor discomfort were also recorded. Conclusion. While volar distal radial fixation is well accepted and indeed commonly performed, the procedure is not without complications. We must pay meticulous attention to detail and technique to optimise results

Aims

As an alternative to external fixators, intramedullary lengthening nails (ILNs) can be employed for distraction osteogenesis. While previous studies have demonstrated that typical complications of external devices, such as soft-tissue tethering, and pin site infection can be avoided with ILNs, there is a lack of studies that exclusively investigated tibial distraction osteogenesis with motorized ILNs inserted via an antegrade approach.