INTRODUCTION

The benefits of combining enhanced recovery after surgery (ERAS) interventions with an outpatient THA/TKA program are uncertain. The primary objective was to compare adverse event rate and secondly to compare pain management, functional recovery, PROMs and patients' satisfaction.

Mechanical alignment (MA) techniques for total knee arthroplasty (TKA) may introduce significant anatomic modifications, as it is known that few patients have neutral femoral, tibial or overall lower limb mechanical axes.

A total of 1000 knee CT-Scans were analyzed from a database of patients undergoing TKA. MA tibial and femoral bone resections were simulated. Femoral rotation was aligned with either the trans-epicondylar axis (TEA) or with 3° of external rotation to the posterior condyles (PC). Medial-lateral (DML) and flexion-extension (DFE) gap differences were calculated.

Extension space ML imbalances (3mm) occurred in 25% of varus and 54% of valgus knees and significant imbalances (5mm) were present in up to 8% of varus and 19% of valgus knees. For the flexion space DML, higher imbalance rates were created by the TEA technique (p < 0 .001). In valgus knees, TEA resulted in a DML in flexion of 5 mm in 42%, compared to 7% for PC. In varus knees both techniques performed better. When all the differences between DML and DFE are considered together, using TEA there were 18% of valgus knees and 49% of varus knees with < 3 mm imbalances throughout, and using PC 32% of valgus knees and 64% of varus knees.

Significant anatomic modifications with related ML or FE gap imbalances are created using MA for TKA. Using MA techniques, PC creates less imbalances than TEA. Some of these imbalances may not be correctable by the surgeon and may explain post-operative TKA instability. Current imaging technology could predict preoperatively these intrinsic imitations of MA. Other alignment techniques that better reproduce knee anatomies should be explored.

Assessing patients' functional outcomes following total hip arthroplasty with traditional scoring systems is limited by their ceiling effects. The Forgotten Joint Score (FJS) has been suggested as a more discriminating option. The actual score in the FJS which constitutes a “forgotten joint”, however, has not been defined. The emerging concept of joint perception led to the development of the Patient's Joint Perception question (PJP) to assess the patient's opinion of their prosthetic joint.

Two hundred fifty-seven THAs were assessed at a mean of 68 months follow-up (range 57–79). Outcomes included the WOMAC, FJS and the PJP. Correlation of the scores as well as the ceiling effects were analysed

The mean FJS was 88.5 (range 27.1–100). PJP was correlated with the FJS and WOMAC (Spearman's rho: −0.510 and 0.465 respectively). Fifty-two percent of the patients felt their hip as a natural joint (FJS CI 95% 93.3–96), 24.1% as an artificial joint with no restriction (FJS CI 95% 83.1–90.5), and 23.3% as an artificial joint with minor restrictions (FJS CI 95% 73.8–82.2). Only 0.8% had major restrictions and none reported a non-functional joint. The ceiling effect was high with both the WOMAC and FJS, with 27.2% and 31.9%. In addition, 28.6% of the patients had a WOMAC >10 and 23.4% a FJS of < 9 0 while reporting having a natural hip. Furthermore, 21.5% with a perfect WOMAC or 21.9% with a perfect FJS, reported having an artificial joint with or without limitation.

A forgotten hip perception corresponds to a FJS >93. In 20–30% of the cases, the WOMAC and FJS failed to identify the forgotten joint, or reached the maximum score when the patients did not feel their hip was natural. The PJP is a simple and reliable tool that enables identification of patients that feel their hip is natural.

For many years, achieving a neutral coronal Hip-Knee-Ankle angle (HKA) measured on radiographs has been considered a factor of success for total knee arthroplasty (TKA). Lower limb HKA is influenced by the acquisition conditions, and static HKA (sHKA) may not be representative of the dynamic loading that occurs during gait. The primary aim of the study was to see if the sHKA is predictive of the dynamic HKA (dHKA). A secondary aim was to document to what degree the dHKA changes throughout gait.

We analysed the 3-D knee kinematics during gait of a cohort of 90 healthy individuals (165 knees) with the KneeKG™ system. dHKA was calculated and compared with sHKA values. Knees were considered “Stable” if the dHKA remained positive or negative – i.e. in valgus or varus – for greater than 95% of the corresponding phase and “Changer” otherwise. Patient characteristics of the Stable and Changer knees were compared to find contributing factors.

The dHKA absolute variation during gait was 10.9±5.3° [2 .4° – 28.3°] for the whole cohort. The variation was greater for the varus knees (10.3±4.8° [2.4° – 26.3°]), than for the valgus knees (12.8±6.1° [2.9° – 28.3°], p=0.008). We found a low to moderate correlation (r = 0.266 to 0.553, p < 0 .001) between sHKA and the dHKA values for varus knees and no correlation valgus knees. Twenty two percent (36/165) of the knees demonstrated a switch in the dHKA (Changer). Proportion of Changer knees was 15% for varus sHKA versus 39% for valgus sHKA (p < 0.001).

Lower limb radiographic measures of coronal alignment have limited value for predicting dynamic measures of alignment during gait.

Mechanical alignment (MA) techniques for total knee arthroplasty (TKA) introduces significant anatomic modifications and secondary ligament imbalances. A restricted kinematic alignment (rKA) protocol was proposed to minimise these issues and improve TKA clinical results.

A total of 1000 knee CT-Scans were analyzed from a database of patients undergoing TKA. rKA tibial and femoral bone resections were simulated. rKA is defined by the following criteria: Independent tibial and femoral cuts within ± 5° of the bone neutral mechanical axis and, a resulting HKA within ± 3° of neutral. Medial-lateral (ΔML) and flexion-extension (ΔFE) gap differences were calculated and compared with MA results. With the MA technique, femoral rotation was aligned with either the trans-epicondylar axis (TEA) or with 3° of external rotation to the posterior condyles (PC).

Extension space ML imbalances (>/=3mm) occurred in 33% of TKA with MA technique versus 8% of the knees with rKA (p /=5mm) were present in up to 11% of MA knees versus 1% rKA (p < 0 .001). Using the MA technique, for the flexion space ΔML, higher imbalance rates were created by the TEA technique (p < 0 .001). rKA again performed better than both MA techniques using TEA of 3 degrees PC techniques (p < 0 .001). When all the differences between ΔML and ΔFE are considered together: using TEA there were 40.8% of the knees with < 3 mm imbalances throughout, using PC this was 55.3% and using rKA it was 91.5% of the knees (p < 0 .001).

Significantly less anatomic modifications with related ML or FE gap imbalances are created using rKA versus MA for TKA. Using rKA may help the surgeon to balance a TKA, whilst keeping the alignment within a safe range.

Background

Achieving a neutral static Hip-Knee-Ankle angle (sHKA) measured on radiographs has been considered a factor of success for total knee arthroplasty (TKA). However, recent studies have shown that sHKA seems to have no effect on TKA survivorship. sHKA is not representative of the dynamic loading occurring during gait, unlike the dynamic HKA (dHKA).

INTRODUCTION

In recent years, there has been a shift toward outpatient and short-stay protocols for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). We developed a peri-operative THA and TKA short stay protocol following the Enhance Recovery After Surgery principles (ERAS), aiming at both optimizing patients’ outcomes and reducing the hospital length of stay. The objective of this study was to evaluate the implementation of our ERAS short-stay protocol. We hypothesized that our ERAS THA and TKA short-stay protocol would result in a lower complication rate, shorter hospital length of stay and reduced direct health care costs compared to our standard procedure.

Background

Mechanical alignment (MA) techniques for total knee arthroplasty (TKA) introduce significant anatomic modifications and secondary ligament imbalances. A restricted kinematic alignment (rKA) protocol was proposed to minimize these issues and improve TKA clinical results.

Background

Assessing patients’ functional outcomes following total knee arthroplasty (TKA) with traditional scoring systems is limited by their ceiling effects. The Forgotten Joint Score (FJS) has been suggested as a more discriminating option. The actual score in the FJS which constitutes a “forgotten joint,” however, has not been defined. The emerging concept of joint perception led to the development of the Patient's Joint Perception question (PJP) to assess the patient's opinion of their prosthetic joint.

INTRODUCTION

Mechanical alignment in TKA introduces significant anatomic modifications for many individuals, which may result in unequal medial-lateral or flexion-extension bone resections. The objective of this study was to calculate bone resection thicknesses and resulting gap sizes, simulating a measured resection mechanical alignment technique for TKA.

The mechanical alignment (MA) for Total Knee Arthroplasty (TKA) with neutral alignment goal has had good overall long-term outcomes. In spite of improvements in implant designs and surgical tools aiming for better accuracy and reproducibility of surgical technique, functional outcomes of MA TKA have remained insufficient. Therefore, alternative, more anatomicaloptions restoring part (adjusted MA (aMA) and adjusted kinematic alignment (aKA) techniques) or the entire constitutional frontal deformity (unicompartment knee arthroplasty (UKA) and kinematic alignment (KA) techniques) have been developed, with promising results. The kinematic alignment for TKA is a new and attractive surgical technique enabling a patient specific treatment. The growing evidence of the kinematic alignment mid-term effectiveness, safety and potential short falls are discussed in this paper. The current review describes the rationale and the evidence behind different surgical options for knee replacement, including current concepts in alignment in TKA. We also introduce two new classification systems for “implant alignments options” (Figure 1) and “osteoarthritic knees” (Figure 2) that would help surgeons to select the best surgical option for each patient. This would also be valuable for comparison between techniques in future research.

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The mechanical alignment (MA) for Total Knee Arthroplasty (TKA) with neutral alignment goal has had good overall long-term outcomes. In spite of improvements in implant designs and surgical tools aiming for better accuracy and reproducibility of surgical technique, functional outcomes of MA TKA have remained insufficient. Therefore, alternative, more anatomical options restoring part (adjusted MA (aMA) and adjusted kinematic alignment (aKA) techniques) or the entire constitutional frontal deformity (unicompartment knee arthroplasty (UKA) and kinematic alignment (KA) techniques) have been developed, with promising results. The kinematic alignment for TKA is a new and attractive surgical technique enabling a patient specific treatment. The growing evidence of the kinematic alignment mid-term effectiveness, safety and potential short falls are discussed in this paper. The current review describes the rationale and the evidence behind different surgical options for knee replacement, including current concepts in alignment in TKA. We also introduce two new classification systems for “implant alignments options” and “osteoarthritic knees” that would help surgeons to select the best surgical option for each patient. This would also be valuable for comparison between techniques in future research.

Management of pseudotumours associated with MoM THA can be difficult and complications are frequent. The functional outcome of patients after revision surgery may be suboptimal. The objective of this study was to assess our experience with revisions of failed MoM THA due to pseudotumours.

78 hips were diagnosed with pseudotumours in 70 patients following metal-on-metal hip replacements. Of these, 68 MoM THA were revised in 62 patients. Pre operative symptoms, radiographic analysis, metal ion levels, MRI results, intra-operative findings, WOMAC scores, the satisfaction level and the complication rate were recorded.

Five patients had a resurfacing arthroplasty as their primary implants while the remaining 63 hips in 57 patients had MoM THA of different brands. The average time between the primary and revision surgery was 69 months (range 15–120). The average age at revision was 59 years (43–87). The mean follow-up was 24 months (range 2–73). 36 patients had minimal one year follow-up. Most lesions consisted of cystic changes and solid lesions were observed in 19 patients. In 57 hips, the pseudotumours were located posteriorly or postero-laterally around the greater trochanter. Intra operatively, muscle necrosis was observed in 15(22%) patients. Most THA cases demonstrated wear and corrosion at the head neck junction of the femoral implants. Thirty-five patients (44.9%) had greater than 50 degrees of cup abduction, including 10 patients (12.8%) with an abduction angle greater than 60 degrees. The average pre operative and postoperative Co ion levels were 27.46 ug/L (range 0.36–145.6) and 2.46 (range 0.4–12.48), respectively. Post revision, a total of 10 hips (14.7%) sustained a dislocation, with seven (10.3%) of them experiencing recurrent dislocations. In 8/10 hips, the femoral head size was 36mm or greater. Revision for dislocation occurred in seven(10.3%) patients. Three(4.4%) deep and one(1.47%) superficial infections occurred and deep infections were re-operated. One(1.47%) fracture of the greater trochanter and one (1.47%) psoas tendinitis did not need revision. Therefore, a total of 10 patients (14.7%) were reoperated. 6 revisions for instability were performed in the first 34 patients, while 1 were done in the last 34 patients. At one year post revision surgery, the mean WOMAC score was 19.68 (range 0–48). In comparison, the mean WOMAC score of the same patients one year after their primary surgery was 8.1 (0–63). Patient satisfaction level of patients one year post revision surgery was 7.61 (range 5–10) compared to 4.15 (range 0–7) pre-revision one.

The complication rate after revision of pseudotumours is high. Most re revisions occurred secondary to instability despite the use of larger femoral heads. The functional outcome at one year post revision seems to be lower than that seen after primary THA but similar to other revisions in the literature. Experience in the management of these patients may reduce the complication rate.

Modifying Knee anatomy during mechanical Total Knee Arthroplasty (TKA) may impact ligament balance, patellar tracking and quadriceps function. Although well fixed, patients may report high levels (20%) of dissatisfaction. One theory is that putting the knee in neutral mechanical alignment may be responsible for these unsatisfactory results. Kinematic TKA has gained interest in recent years; it aims to resurface the knee joint and preservation of natural femoral flexion axis about which the tibia and patella articulate, recreating the native knee without the need for soft tissue relaease. That's being said, it remains the question of whether all patients are suitable for kinematic alignment. Some patients' anatomy may be inherently biomechanically inferior and recreating native anatomy in these patients may result in early implant failure. The senior author (PAV) has been performing Kinematic TKA since 2011, and has developed an algorithm in order to better predict which patient may benefit from this technique.

Lower limb CT scans from 4884 consecutive patients scheduled for TKA arthroplasty were analysed. These exams were performed for patient-specific instrumentation production (My Knee®, Medacta, Switzerland). Multiple anatomical landmarks used to create accurate CT-based preoperative planning and determine the mechanical axis of bone for the femur and tibia and overall Hip-knee-Ankle (HKA). We wanted to test the safe range for kinematic TKA for the planned distal resection of the femur and tibia. Safe range algorithm was defined as the combination of the following criteria: – Independent tibial and femoral cuts within ± 5° of the bone neutral mechanical axis and HKA within ± 3°. The purpose of this study is to verify the applicability of the proposed safe range algorithm on a large sample of individual scheduled for TKA.

The preoperative tibial mechanical angle average 2.9 degrees in varus, femoral mechanical angle averaged 2.7 degrees in valgus and overall HKA averaged of 0.1 in varus. There were 2475 (51%) knees out of 4884, with femur and tibia mechanical axis within ±5° and HKA within ±3° without need for bony corrections. After applying the algorithm, a total of 4062 cases (83%) were successfully been evaluated using the proposed protocol to reach a safe range of HKA ±3° with minimal correction. The remaining 822 cases (17%) could not be managed by the proposed algorithm because of their unusual anatomies and were dealt with individually.

In this study, we tested a proposed algorithm to perform kinematic alignment TKA avoiding preservation/restoration of some extreme anatomies that might not be suitable for TKA long-term survivorship. A total of 4062 cases (83%) were successfully eligible for our proposed safe range algorithm for kinematic TKA. In conclusion, kinematically aligned TKA may be a promising option to improve normal knee function restoration and patient satisfaction. Until we have valuable data confirming the compatibility of all patients' pre arthritic anatomies with TKA long-term survivorship, we believe that kinematically alignment should be performed within some limits. Further studies with Radiostereometry or longer follow up might help determine if all patients' anatomies are suitable for Kinematic TKA.

Large bearing surfaces are appealing in total hip arthroplasty (THA) as they may help create a greater range of impingement free motion and reduce the risk of dislocation. However, attempts to achieve this with a metal bearing surface have been blighted by adverse reactions to metal debris. Ceramic bearings have a good long-term track record in more conventional head sizes, and manufacturing techniques now permit the use of larger ceramic bearing surfaces using monoblock uncemented acetabular components. In this study, we are reviewing the early results of the Maxera® acetabular component (Zimmer, Indiana) at our institution.

All data was collected prospectively. Maxera® acetabular component is a Titanium (Ti) shell with plasma sprayed Ti for the osteointegrative surface. Delta ceramic liner is inserted & locked into the cup shell by the manufacturer (non-modular). With the Maxera cup system, the bearing diameter is dictated by the acetabular component size. Acetabular components (AC) of 46 and 48 mm have a bearing diameter (BD) of 36 mm, AC of 50 and 52 mm: have a 40 mm BD, AC of 54 and 56 mm: have a BD of 44 mm and AC of 58–64: have a 48mm BD. Delta ceramic femoral head size of 44 and 48 mm have a modular Ti sleeve between the head and femoral stem trunnion. Femoral head sizes of 36 and 40 mm have no Ti sleeve. All THA had an uncemented femoral stem. Implants were inserted with a posterior approach. Patients were reviewed at 6 weeks, 6 months and then annually with radiographs. Clinical function was evaluated using WOMAC and UCLA scores along with joint perception questionnaires.

Five hundred components have been implanted in 442 patients (250 women, 192 men) with a mean age of 55, (min 17, max 80) and a mean BMI of 26.9 (min 17.8, max 51). The mean acetabular size was 54 (min 46, max 64), leading to a mean femoral head size of 44. At a minimum of two years follow-up (mean 3.8 years): 5 patients have been revised, 4 secondary to undetected intraoperative fracture of the femur and only one due to early displacement of a Maxera® cup (0.2%). Five patients reported a mild squeaking; two reported clicking and one patient presented with a symptomatic heterotopic ossification. The WOMAC score improved significantly post-operatively, (57.4 compared to 4.4 post-operatively, p<0.001). The mean post-operative UCLA score was 6.9. Sixty percent (60.6%) of patients rated their joint perception as either “natural” or “artificial without limitation”. two patients (0.4%) suffered a dislocation after high velocity trauma without recurrence after closed reduction. No ceramic component fracture was recorded.

This prospective study shows that this monoblock acetabular component provides an easy implantation with minimal complications. The ceramic bearing surface provides good clinical function and joint perception. Bearing surfaces of this design may provide an alternative to large head metal on metal (MoM) implants without the side effects of metal debris/ions.

Purpose

The purpose of the study was to determine the rate of conversion from RSA to THR in a number of Canadian centers performing resurfacings

Purpose: Even with modern ancillary and good surgical experience, rotational implant positioning is sometimes sub-optimal, leading to poor results. Except for obvious cases with patellar instability, the symptoms are often vague and non-contributive to the diagnosis of failure. This is why implant malpositioning and particularly malrotational postioning remain an underestimated cause of failure after primary total knee arthroplasty (TKA). We report our experience with TKA revision for rotational malpositioning.

Method: We retrospectively assessed the results of TKA revisions in 22 knees for malrotational positioning. In all cases, malrotational implant positioning was confirmed by CT-scan according to Berger’s protocol.

Results: Mean age was 66 years (47–74) at the time of the primary TKA. After the index procedure, all patients presented early anterior knee pain with patellar instability (tilt and subluxation in ten cases, and permanent patellar dislocation in two cases). Malrotational positioning predominated on the tibial component with mean 23° internal rotation. Mean cumulative malrotation (tibial plus femur) was 22° internal rotation. All but four patients underwent femoral and tibial component revision. In two cases, only the tibial component was revised, and in two other cases, isolated transposition of the anterior tibial tuberosity was carried out. One was a failure, and finally underwent a successful full revision. At a mean follow-up of 30 months (12–60), we noted significant functional outcome improvement. One patient, who underwent a patellectomy previously at the index TKA procedure, had persistant anterior knee pain. No patient presented patellar instability.

Conclusion: The diagnosis of implant malrotational positioning is sometimes difficult. The most common errors are tibial component positioning. In case of suspicion of malrotational positioning, protocolized CT-scan allows quick and simple diagnosis. If the malrotation is confirmed, TKA revision should be performed upon patient disability and severity of the symptoms. It is important not to delay the surgery, particularly in cases of patellofemoral dislocation because of the risks of developing soft tissue contractures resulting in a more difficult revision procedure.

Purpose: Massive cavitary and segmental bone defects of the medial wall in revision arthroplasty are usually managed with large auto and/or allograft in association with a cemented or a cementless cup. To obtain a satisfactory hip center reconstruction with such a procedure can be sometimes challenging and the complications rate can be high. One other option is the use of a cup with a medial expansion (“protrusio cup”) to treat the medial bone defect.

Method: We carried out a retrospective study including 21 consecutive acetabular revisions arthroplasties using a cementless Converge Protrusio™ cup (Zimmer, Warsaw, IN, USA). Clinical outcomes were assessed by Harris Hip Score (HHS), WOMAC index and SF-12. Hip centre was assessed on anteroposterior (AP) view and the reconstruction was considered as satisfying when its location was located from − 10 to + 10 mm proximally (y axis) and/or medially (x axis) in comparison with ideal theoretical hip center location. Cup migration and modification of abduction angle were considered as significant when there were respectively > 4mm and to > 4° in comparison with the immediate postoperative AP view.

Results: At the last follow up [radiological data: 71.6 months (24–128.3) and clinical data: 72.1 months (24–129.5)], two patients were died and there were no lost of follow up. The mean HHS was 79.4% (52–100), WOMAC 82% (46–100), SF-12 52 (23–71) and 44 (18–65). Bone defect were filled with cancellous bone chips allograft in 16 cases and bulk bone allograft was used in only two cases to manage a large segmental defect of the roof. Bone graft integration was completed in all cases. The mean abduction cup angle was 43.6° (32–60). A satisfying hip centre positioning was obtained in 19 cases on x axis and in 10 cases on y axis, in all the remaining cases, we noted an improved implant positioning. The complications were: recurrent dislocation in one case (successfully revised with a constrained liner), infection in two cases (1 treated conservatively and the other one revised in two times procedure) and Brooker’s type III and IV ectopic ossifications in three cases. A significant cup migration occurred in only one case at nine years but was not revised because of painless. No case required revision for aseptic loosening.

Conclusion: Protusio cups appear as a reliable procedure to manage bone loss in acetabular revision. The revision procedure is widely simplified by reducing the use of the massive allograft and by promoting a satisfying hip center reconstruction to allow an optimal biomechanical joint functioning. Moreover, the cementless fixation in contact with patient acetabular bone makes more easy bone integration.

Purpose of the study: The purpose of this work was to compare the subjective and functional outcomes of patients with a large diameter total hip arthroplasty (LD-THA) or hip resurfacing (HR).

Material and methods: Forty-eight persons were assessed and double blind randomised to receive either LD-THA (n=24) or HR (n=24). The clinical and radiographic assessment and gait analysis were performed preoperatively and at three, six and 12 months postoperatively. Gait analysis was performed once in a third group of healthy adults (n=14) who served as controls.

Results: The two groups were comparable preoperatively regarding demongraphic and functional characteristics. Postoperatively, the two groups with prostheses exhibited very rapid recovery with normalization of test results compared with controls within three to six months. The clinical assessment, the analysis of postural balance, gait analysis and most of the specific tests were not different between the two groups with prostheses.

Conclusion: There was no remarkable difference in subjective or objective assessments between subjects with a LD-THA or HR. This suggests that the only potential advantage of HR is the preservation of femoral bone stock. Long-term HR implant survival will determine the reality of this benefit.

Purpose of the study: A medial incision for implantation of a total knee arthroplasty (TKA) offers an excellent surgical exposure while minimising the length of the skin opening. This incision however implies section of the proximal portion of the infrapatellar branch of the medial saphenous nerve, potentially associated with lateral hypoesthesia and formation of a neuroma (painful scar). We hypothesised that an anterolateral skin incision would produce less hypoesthesia and postoperative discomfort.

Material and methods: We conducted a prospective randomised study to compare the degree of hypoesthesia after a medial or lateral skin incision for the implantation of a TKA. Fifty-knees in 43 patients, mean age 65.9±8.4 years were included; 26 knees for the lateral incision and 24 for the medial. All patients had the same type of implant. Clinical results were assessed with WOMAC, KOOS and SF36. Semme-Weinstein monofilaments were applied to measure sensitivity at 13 characteristic points. Patients were assessed at six weeks and six months. The zone of hypoesthesia was delimited and photographed for measurement with Mesurim Pro9^®. Satisfaction with the surgery and the scar was noted. Data were processed with Statview^®; p< 0.05 was considered significant.

Results: The two groups were comparable preoperatively regarding age, gender, body weight, height, body mass index, body surface area, aetiology, and clinical score. Operative time, blood loss, and number of complications were comparable. The functional outcomes (WOMAC, KOOS, SF36) were comparable at six weeks and six months. Active flexion was significantly greater at six months in the lateral incision group (p=0.03). The zone of hypoesthesia was significantly smaller in the lateral incision group at six weeks (p< 0.01) and at six months (p< 0.01), as were the number of points not perceived on the filament test (p< 0.01 in both cases) while the length of the incision was comparable (p> 0.05). This was associated subjectively, with less loss of sensitivity and less anterior pain reported by the patient at six months.

Discussion: Lateral and medial incisions enable comparable functional outcomes. The lateral incision produces less hypoesthesia and less anterior pain. This improves the immediate postoperative period and facilitates rehabilitation as is shown by the gain in flexion at six months.